rev_wrmp
TRANSCRIPT
Dŵr Cymru Welsh Water
Revised Draft Water Resources Management Plan
October 2011
TABLE OF CONTENTS
INTRODUCTION, SUMMARY, AND CONSULTATION PROCESS .......................................................................... 1
CHAPTER 1. WATER RESOURCES MANAGEMENT PLANS ............................................................ 11
1.1 Why we prepare plans .......................................................................................................... 11
1.2 Our approach to the development of this plan ...................................................................... 11
1.3 Our 2008 plan........................................................................................................................ 11
1.4 Other Developments since the 2008 Plan ............................................................................ 12
1.5 Strategic Links ....................................................................................................................... 14
1.6 Compliance with Welsh Government Direction ..................................................................... 15
CHAPTER 2. SUPPLYING WATER IN OUR AREA .............................................................................. 17
2.1 Water resources in our supply area ...................................................................................... 17
2.2 Water Resource Zones - General ......................................................................................... 19
CHAPTER 3. WATER SUPPLY CAPACITY ........................................................................................... 25
3.1 Deployable Output ................................................................................................................ 25
3.2 Resource Developments during 2005-2010 ......................................................................... 27
3.3 Other changes since the 2008 Draft Plan ............................................................................. 27
3.4 Outage ................................................................................................................................... 27
3.5 Levels of Service (LoS) ......................................................................................................... 29
3.6 Operational use of water ....................................................................................................... 31
3.7 Water Transfers..................................................................................................................... 31
3.8 Elan Builth ............................................................................................................................. 32
3.9 Non-Potable Supplies ........................................................................................................... 32
3.10 Other customers .................................................................................................................... 32
3.11 Water Available for Use ........................................................................................................ 32
CHAPTER 4. THE DEMAND FOR WATER ............................................................................................ 34
4.1 Baseline demand .................................................................................................................. 34
4.2 Population forecasts .............................................................................................................. 36
4.3 Property Forecasts ................................................................................................................ 38
4.4 Household Demand .............................................................................................................. 39
4.5 Non Household Demand ....................................................................................................... 40
4.6 Distribution Input ................................................................................................................... 41
4.7 Managing Demand ................................................................................................................ 45
CHAPTER 5. TARGET HEADROOM ...................................................................................................... 53
5.1 Calculating Target Headroom ............................................................................................... 53
5.2 Risk Profile ............................................................................................................................ 54
5.3 Baseline and Final Planning .................................................................................................. 54
5.4 Work carried out since the 2008 Draft Plan .......................................................................... 54
CHAPTER 6. THE HABITATS DIRECTIVE AND THE IMPACT ON WATER ABSTRACTIONS ...... 56
6.1 The Habitats Directive ........................................................................................................... 56
6.2 Review of Consents (and Restoring Sustainable Abstraction programme) .......................... 56
6.3 The impact of Review of Consents upon Resources ............................................................ 65
CHAPTER 7. UNCERTAINTY REGARDING THE EFFECTS OF CLIMATE CHANGE ..................... 67
7.1 How we approach climate change ........................................................................................ 67
7.2 The impact on supply ............................................................................................................ 68
7.3 The Impact on Target Headroom - Supply ............................................................................ 70
7.4 The Impact on Target Headroom – Demand ........................................................................ 74
CHAPTER 8. THE SUPPLY DEMAND BALANCE ................................................................................ 76
8.1 Calculating the Supply Demand Balance .............................................................................. 76
8.2 The projected Supply Demand balance ................................................................................ 76
8.3 Brecon Portis ......................................................................................................................... 78
8.4 Pembrokeshire ...................................................................................................................... 79
8.5 South East Wales Conjunctive Use System (SEWCUS) ...................................................... 81
8.6 North Eyri Ynys Mon ............................................................................................................. 82
CHAPTER 9. OPTION APPRAISAL ........................................................................................................ 83
9.1 Our approach to appraising the options ................................................................................ 83
9.2 Identifying the feasible options .............................................................................................. 84
9.3 Feasible List .......................................................................................................................... 85
9.4 Environmental and Social costing ......................................................................................... 89
9.5 Selecting the preferred option ............................................................................................... 91
9.6 Optimisation model ............................................................................................................... 91
9.7 Preferred Options for Addressing Supply Demand Deficits (Without Incorporating the Full Range of UKCP09 Climate Scenarios in Target Headroom) ............................................................ 92
9.8 Preferred Options for Addressing Supply Demand Deficits, Incorporating the Full Range of UKCP09 Scenarios in Target Headroom .......................................................................................... 97
9.9 Sensitivity ............................................................................................................................ 103
CHAPTER 10. ENVIRONMENTAL APPRAISAL ................................................................................... 107
10.1 Introduction .......................................................................................................................... 107
10.2 Strategic Environmental Assessment ................................................................................. 108
10.3 Habitats Regulations Assessment ...................................................................................... 109
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Introduction, Summary, and Consultation Process
One of our most important responsibilities, as provided for under the Water Industry Act 1991, is to
ensure that we can always meet the reasonable water needs of our customers now and into the
future. And, like all other water companies, we are required periodically to produce a Water
Resources Management Plan which demonstrates how we plan to balance supply and demand over
the following 25 years. Although companies had produced Water Resources Plans on a voluntary
basis for several years previously, the amendments to the 1991 Act which were made by the Water
Act 2003 introduced for the first time a statutory requirement for companies to produce Water
Resources Management Plans (WRMPs).
As part of our preparation for the 2009 regulatory price-setting process, we submitted a Draft Water
Resources Management Plan to the Welsh Government in March 2008. Following a Direction from
the Welsh Government in January 2009, the Plan was published for consultation on 15 January 2009.
However, it did not complete the full statutory process as it was never formally approved by the Welsh
Government, primarily due to fact that, in certain important respects, it was overtaken by events,
notably the need to consider the impact of the Habitats Directive.
This document is therefore a revised draft of our Plan for the period up to 2035, and sets out for
consultation how we intend to achieve the required balance between supply and demand. Our aim is
to do so efficiently so that water bills are no higher than they need to be and the impact on our
environment is minimised. In order to develop the plan, we have projected the future demand for
water from our customers, we have calculated how much will be available from current sources, and,
where there is a shortfall, looked at all the ways of increasing supply and reducing demand so as to
arrive at the best overall package of solutions.
In general, we are currently in a relatively strong position on water resources. Wales has a
comparatively wet climate and we abstract for public water supply just 3% of effective rainfall (which
compares with much higher figures in parts of the South East of England, for example). Demand for
water and the amount of water we abstract has fallen by a quarter over the last 15 years (as a result
of halving of leakage and falling industrial demand for water) and we are forecasting more or less flat
demand for water from our customers over the coming 25 years. This is based on Government and
local authority projections of population and properties, and assumes no major upturn in the demand
for water from heavy industry. All our 24 water resource zones currently have a surplus of supply
over demand in both a normal and a Dry Year.1
However, we do not expect this situation to persist. Much of this document is concerned with the
significant changes in our water resources position that we are expecting in the coming years. We
have to plan and cater for likely and possible changes in the years ahead, and for this Plan those are
greater and more serious than they have been for the last two or more generations.
Specifically, the Plan has been prepared so as to take account of two very significant influences:
the results of the Environment Agency Wales‟ “Review of Consents” exercise which it has
undertaken in the light of the European Habitats Directive. A significant feature of this
process is that it entails the application of a “precautionary principle” under which potential
adverse impact of abstraction is presumed unless evidence is available to the contrary, which
typically is not the case; and
1 A “Dry Year” is defined as a year that is characterised by low rainfall and unconstrained demand. The Dry Years that we have
experienced and which are incorporated in our modelling include 1976, 1984, and, for some zones, 2003.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
an updated assessment of the possible impact of climate change on the water environment in
Wales, as set out in the latest UK Climate Change Projections published in 2009 (“UKCP09”),
which may both reduce the amount of water we have available to supply, and increase
demand from our customers.
Together, these two developments could very significantly reduce or eliminate our water resource
surpluses, in some zones creating deficits that could require significant investment to address. For
example, in our South East Wales Conjunctive Use System zone (“SEWCUS”) which covers much of
South East Wales, the Review of Consents process alone will reduce our Deployable Output by
nearly 20%, the equivalent of what we need to meet the needs of consumers in the whole of Cardiff.
More generally, the resultant tightening of our water resource position means that surpluses that we
currently have cannot be regarded as being available to support long term economic development.
For example, on the basis of the projections set out in this plan water is unlikely to be available to
supply the new Wylfa power station on Anglesey, and new resources would probably be required to
facilitate any further industrial development in Milford Haven.
We want to test our understanding and current thinking with all who have an interest in the water
industry and the environment in Wales. We want our customers and other stakeholders to engage
with us on the challenges we face in maintaining a balance between supply and demand for water
and how we propose to meet them. And if there is one key message we want to get across from this
discussion and consultation it is that Wales does not have an abundance of water for public water
supply and that we all need to value our water resources much more than in the past.
The feedback we receive will not only assist us in shaping the final Plan, but will also influence our
approach to the next draft Water Resource Management Plan, due in 2013.
Structure of draft Plan
This document is structured as follows. Chapter 1 sets out the context within which the revised draft
plan has been prepared, and the processes that have been applied. Chapter 2 provides a summary
of the key features of our region and the water supply industry in general that are particularly relevant
for water resources planning. Chapter 3 then explains the primary measures of water supply
capacity, namely “deployable output” and “water available for use” (including the role of “outage”), and
Chapter 4 describes the main elements of the demand for water in our region together with the basis
on which we have forecast demand out to 2035. Chapter 4 also summarises our approach to the
management of leakage (leakage being one component of the “demand” for water) and the promotion
of water efficiency, both of which will continue to play important roles in our water supply strategy over
the Plan period. Chapter 5 then explains “Target Headroom”, the buffer that we build into our
projections to allow for error and uncertainty for the purposes of determining when there is deemed to
be a supply demand “deficit”.
Chapters 6 and 7 describe two exceptional influences on our water resources position over the Plan
period. These are respectively the notification we have had from the Environment Agency that it has
reviewed some of our licences and wants us to make significant “sustainability reductions” in the light
of the Habitats Directive (reductions that we are assuming will come into effect in 2020), and the latest
projections for climate change. Chapter 8 brings together the projections of demand, Target
Headroom and Deployable Output to present the „supply demand balance‟ for each of our 24 water
resource zones for the period to 2035. We show that, but for the effects of the Habitats Directive
related review of our consents and climate change, we would be projecting no supply demand deficits
over the next 25 years, but when they are taken into account deficits appear in some zones during the
plan period.
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Chapter 9 then sets out how we have approached the evaluation of options for closing these deficits.
These options range from increasing the storage available in our reservoirs to encouraging our
customers to use water more efficiently. It shows how we have evaluated the options to arrive at a
preferred list of viable solutions to the projected deficits. It sets out our initial estimates of the likely
financial and carbon cost of progressing each of these options and the possible impact on customer
bills.
Finally, Chapter 10 summarises the environmental appraisals we have commissioned in connection
with, and to support this Plan. A glossary of terms is included with the supporting Annexes.
Building the Uncertainty Surrounding Climate Change into this Plan
The biggest challenge we faced in preparing this plan was the question of how we should incorporate
the latest climate change scenarios, “UKCP09”,into our projections, and particular the uncertainty
around the central projections. We are the first water company to use UKCP09 scenarios in the
preparation of a water resources management plan, and the Environment Agency‟s guidance on how
they should be incorporated is still under development. Following “best practice” in dealing with the
uncertainty around climate change, we found that the UKCP09 scenarios had a very dramatic effect
on the supply demand position in some parts of our region, notably the large South East Wales
Conjunctive Use System zone that relies extensively on the River Usk and the Wye. From a baseline
position in which the zone would be 75 megalitres per day (Ml/d) in surplus in 2035, the Review of
Consents takes the zone into a small 3 Ml/d deficit and incorporating the median climate change
scenarios in calculations of Deployable Output extends this to 12 Ml/d. Allowing for the full range of
UKCP09 scenarios on uncertainty in Deployable Output in Target Headroom, however, takes the
projected deficit to 104 Ml/d by the end of the Plan period.
Faced with this dramatic effect, we considered three options:
A. plan on the basis of the full range of UKCP09 scenarios and present the options for
addressing supply-demand deficits such as the one for SEWCUS referred to above;
B. use the full range of UKCP09 scenarios, but discount their effect on a sliding scale,
progressively more deeply the further into the future one is projecting. The rationale for this
approach, which is used by several companies and is acknowledged in the Environment
Agency‟s guidance, is that the more distant the uncertainty, the more time and scope there is
available in the meantime to deal with it; or
C. calculate and disclose the effects on Target Headroom of the full range of UKCP09 scenarios,
but plan to address supply-demand deficits that exclude them.
We did not adopt option B because we believe it has the unhelpful characteristic of blurring the
quantification and the management of uncertainty. We do not think that it makes sense to plan
investments for an artificial scenario that acknowledges what it is that you think is going to happen but
only addresses a part of it on the grounds that it is a long way into the future. We prefer to be explicit
as to the magnitude of the risks we face, and to address them using considered judgement.
We have evaluated in general terms what option A would mean for our investment plans. Chapter 9
presents our view of what they would entail, including the prospect of significant investment in
desalination in South East Wales. We have not, however, followed option A in arriving at the final
planning solutions for the purposes of this document, and have applied option C instead. Whilst we in
no way understate the importance and potential impact of climate change on our future water supply
position, given that the application of UKCP09 is a developing area, given that the potential supply
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
demand deficits driven by uncertainty around climate change do not manifest themselves for several
years, and given that we are due to prepare our next draft Plan at the same time as the other water
companies in 2013, we have chosen in this document to confine our projections to the supply demand
deficits that we are most confident we will have to address during the Plan period, and the least cost
way of dealing with them. We do, however, present for information supply demand projections using
the full range of UKCP09 scenarios in Target Headroom, and what would be the preferred means of
addressing deficits under this alternative approach.
In the meantime, we believe that we will be in a position to take a much more definitive view of the
likely magnitude of such deficits and how they can best be addressed when we embark upon the next
water resource management planning exercise in a year or so.
The Timing of Licence Adjustments under the Review of Consents
It is also worth highlighting that we have assumed, for the purposes of this Plan, that the licence
amendments in the South East Wales Conjunctive Use System zone will not be formally put in place
until 2020. Having said that, the sustainability reductions would not put the zone into deficit straight
away - rather, according to current modelling, they would leave a small planning surplus for the time
being. The size of the reductions contemplated is so dramatic that we consider that it would be
prudent to carry out further detailed work on the way that the zone is operated in order to ensure that
it is fully robust to such radical changes.
Our Strategy Summarised
The key elements of our overall strategy can be summarised as follows:
regional leakage is expected to fall from 190.45 Ml/d in 2010-11 to 184.08 Ml/d in 2014-15.
This strategy is in line with the targets agreed with our economic regulator, Ofwat. As part of
the option selection process for addressing supply demand deficits we have considered
options involving more reductions in leakage. However, none have been selected because of
their comparatively high costs;
the promotion of a wide range of water efficiency activities for both our domestic and business
customers. For the period 2010-15 we will continue with our full suite of baseline promotion
activities;
the installation of water meters at all new properties and those households who opt to be
metered under our free meter option scheme. We will continue to meter all new business
customers and carry out selective metering on high water use unmeasured business
premises;
for Pembrokeshire, where the deficit has been driven by the potential impacts of climate
change and the significant impact of sustainability reductions being proposed by the
Environment Agency, we are proposing to reinstate a currently licence-exempt groundwater
source and carry out a network scheme that will enhance the connectivity of the zone. This is
the most economic solution for the zone;
in the Brecon – Portis water resource zone where the Environment Agency wants us to
reduce our abstractions from the River Usk at Brecon, we plan to supplement the available
flow in the river with additional releases from the Usk reservoir, when required; and
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
in the South East Wales Conjunctive Use System zone, where we must address the effects
of the Agency‟s review of our abstractions on the protected habitats in the Wye and the Usk,
plus the effects of climate change on Deployable Output. We plan to reinstate two reservoirs
that we have not used for public water supply for some time, namely Wentwood and Grwyne
Fawr, and to build new treatment works for both sources.
For the Preferred solutions in the three deficit zones, the total capital cost is estimated at £35.7m with
a total operating cost, in the entire planning period, of £9.1m. We estimate that this will add
approximately £5 to our average bills in today‟s prices by the end of the Plan period.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Questions we are asking
We would like comment and feedback on this Revised Draft Water Resources Management Plan so
that we can ensure that the Final Plan takes account of as many stakeholder views as possible. We
will also take account of further advice from our regulators in preparing the Final Plan, which we
expect to publish in Spring 2012.
In developing this plan we have followed a structured process, as described in this document. We
summarise below the findings we have reached and ask specific questions on which we would
welcome feedback.
Q1 Are there any important issues that have not been adequately considered in our
assessments of the future water supply and water demand position?
At the start of this process we have identified the Level of Service we will guarantee our customers
namely:
not more than once in every 20 years, on average, for a hosepipe ban, and
not more than once every 40 years, on average, for Drought Orders/ Permits.
We view the imposition of rota cuts and standpipes as unacceptable.
Q2 Is our target level of service, i.e. the frequency of water restrictions and other drought
powers, acceptable, and does it strike the right balance between the needs of customers and
the environment?
We have described how we calculate the amount of water we can supply and how we forecast the
demand for water, and have concluded that all our water resource zones are projected to be in
surplus for the whole of the 25 year Plan period, unless the projected effects of climate change and
the review of our consents that the Environment Agency has carried out in the light of the Habitats
Directive are taken into account.
We have highlighted that the Environment Agency‟s review of our licences and the resultant
modifications it intends to make to our abstractions for both water resource and fish entrainment
impacts require investment by Welsh Water and would increase the bills paid by our customers.
Under the Habitats Directive, the Environment Agency is obliged to use “best available data” which in
the case of the impacted rivers is sparse. Without this data, the Agency has adopted the most
stringent “precautionary principle”, based on a generic approach.
Q3 Should we undertake further research work into whether it can be demonstrated that there
is “no adverse impact” from our abstractions on sites protected by the Habitats Directive?
We believe that there may be a case for a programme of scientific investigation that would allow us
better to define what each of the features in sites protected under the Habitats Directive need in terms
of river flow. This might reduce the number of sites where a lack of scientific evidence combined with
the default “precautionary principle” has resulted in the Environment Agency seeking reductions in the
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
volumes of water we remove from Habitats Directive sites. This would also give us confidence that the
investment suggested in this plan would be beneficial, and deliver value for money.
Q4 If we are to undertake further research how might this best be done and what would be the
sensible areas to focus on?
Notwithstanding the above, the Environment Agency has the responsibility to decide what
amendments are required to our licences. Our primary role is to identify, as a result of their
conclusions, the options available to us to ensure we continue to provide sufficient water to our
customers in line with the commitments we have given. We have described how we have identified
our preferred options and these have been summarised in chapter 10.
Q5 Are the options we have identified the most appropriate ways of securing future water
supplies? Are they both robust and flexible?
Q6 Are there any alternative options that we should consider and why might these be better
than the ones we have identified?
As set out above, we have chosen not to reflect uncertainty surrounding the full effects of climate
change on Deployable Output in our central projections, but we have evaluated what they would look
like and what impacts they have on the least cost strategy for balancing supply and demand.
Q7 Do you agree with our treatment of climate change uncertainty? If not, what alternative
approach do you advocate?
After identifying the options for meeting supply demand deficits we have also described how we have
undertaken environmental assessments of our Plan.
Q8 Does our environmental assessment, outlined in our Strategic Environment Assessment
and our Habitats Regulations Assessment, identify the most relevant potential impacts of the
proposed options?
Finally we highlight that the financial impact of our preferred options is a total cost of £35.7m in capital
expenditure and a total operating expenditure over the plan period of £9.1m, which would mean a bill
increase of around £5 per household in today‟s prices.
Q9 Do you think our proposals represent good value for money?
Of course, as well as these specific questions we welcome comments on any aspects of our Plan. If
you are within our supply area, please write to the Welsh Government at the following address:
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Olwen Minney,
Water Policy Manager
Water Policy Branch
Welsh Government
Cathays Park
Cardiff CF10 3NQ
Comments may be sent by post or email. It would be helpful if the subject title in your email or letter
includes the words “Representation on Dŵr Cymru Welsh Waters‟ Revised Draft Water Resources
Management Plan”.
We will inform you through our Statement of Response how we plan to take your comments into
account in preparing our Final WRMP.
Future Challenges
There are a number of key areas that will present great challenges for us and the rest of the water
industry over the next 5-10 years. We have summarised these in the following table along with our
intended approach to dealing with these challenges.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Issue Going Forward
Climate Change
We have taken a pragmatic approach to the adoption of the latest UK
climate chamge projections (“UKCP09”) in advance of accepted
industry guidance. By the time we prepare the next draft Plan in 2013,
however, it is likely that the Environment Agency will have set out its
position on how UKCP09 scenarios should be incorporated in water
resource management planning, especially Target Headroom. This
may impact on the deficit position.
Water Framework Directive
In December 2009 the first round of River Basin Management Plans
were published setting out the actions and strategies for rectifying
those water bodies currently failing their objectives. During our current
(2010-2015) investment programme we anticipate that investigations
that are underway into these failures could lead to further modifications
to our operations being required.
We are on the steering group of a key UK water industry research and
development project2 and will therefore contribute to decisions
affecting how we should meet the Directive in our current and future
investment programmes.
Restoring Sustainable
Abstraction Programme
(RSAp)
The Environment Agency‟s Restoring Sustainable Abstraction
Programme is ongoing within Wales and we are aware there are a
number of sites that the EA wishes to investigate further to assess
what impact our operations are having upon the ecological integrity.
We remain concerned regarding further investigations in this area and
encourage the Agency to share this with us and allow us to work
together.
Review of the Plan
In preparing this Revised Draft Plan we have undertaken many detailed studies. However, water
resources planning is a dynamic process and we are committed to reviewing the key elements of the
Plan, almost on a continual basis.
In particular, between now and the Final Plan we will take account of consultee responses and
regulatory and industry developments in preparing our Final Plan. This feedback will also play a
significant role in shaping our preparatory work for the draft Plan we intend to publish in 2013.
We also intend over the next two years to:
review in full our demand forecasts (in particular taking account of the high demands
experienced during the summer of 2010);
2 UKWIR research project reference WR33 on Heavily Modified Water Bodies
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
revise our Economic Level of Leakage assumptions in line with Ofwat requirements for water
company investment programmes for 2015-2020;
review and update the inflow sequences on which we base our deployable outputs;
revise our water resources models and drought triggers to account for changes in legislation
that prescribe the restrictions we can apply during droughts (this may impact on the
Deployable Output of some our water resource zones); and
maintain our supply demand balances in line with industry best practices.
All these elements are likely to change the supply demand balance in some water resource zones
and change the overall aspect of the water resources management plan for our 2015-2020
investment programme.
Finally, we will continue to discuss and review the key elements of the Plan through our close working
relationship with the Environment Agency and other stakeholders. We expect to publish our Final
Plan in Spring 2012.
More generally, it is clear that the next few years will see a considerable amount of further work on
the challenge of meeting water resource objectives in Wales, including in particular the creation of an
improved evidence-based understanding of the impact of our abstractions on the environment. It is
vital that the major strategic decisions that we make are the right ones both for current and future
generations, and to this end we will seek to work yet more closely and openly with our stakeholders,
especially our regulator the Environment Agency, over the medium term.
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Chapter 1. Water Resources Management Plans
The purpose of this chapter is to set out the legal context within which this revised draft Plan has been
prepared and how we have approached the task of putting it together. This includes a description of
how our work has evolved since the previous plan in 2008, and how it links in, at a strategic level, with
Government and regulatory policies and requirements.
1.1 Why we prepare plans
Under the Water Industry Act 1991 all water companies are required to provide customers with a
reliable supply of water for domestic and business purposes. Although companies had produced
Water Resources Plans on a voluntary basis for several years previously, the amendments to the
1991 Act which were made by the Water Act 2003 introduced for the first time a statutory requirement
for companies to produce Water Resources Management Plans.
Under these provisions, we are required to prepare a draft Water Resources Management Plan and
to consult with our customers and with other stakeholders as to its content. We regard this as a
highly important exercise for our business: the security of water supplies is of paramount importance
to our customers, and the way in which we achieve this can have significant implications for the costs
we incur and hence the bills customers pay.
1.2 Our approach to the development of this plan
The planning of long term water supplies is not a discrete task that takes place every few years:
rather, we review on a continual basis our water resource position, the future requirements of our
customers, and how they can best be met at least cost to them and at minimal impact to the
environment. This plan therefore represents a “snapshot” of our most up-to-date thinking. It has
been prepared in accordance with guidance provided by the Environment Agency3 and, notably, takes
into account the effects of the review of consents that the Agency has undertaken in the light of the
Habitats Directive(see chapter 6 for details) and includes a full consideration of the latest projections
of the effects of climate change (see chapter 7).
As set out in chapters 8 and 9, we have identified three Water Resource Zones where we are
expecting a supply-demand deficit during the Planning period. In order to determine how best these
can be addressed we have identified and costed all the possible options for increasing supply and/or
reducing demand, including a full evaluation of their environmental, social and carbon costs.
It is important that we understand the potential environmental and ecological impact of any plans we
put forward. We have therefore undertaken a “Strategic Environmental Assessment” (SEA) and a
“Habitats Regulations Assessment” (HRA) of our preferred options for addressing the deficits. These
are described in more detail in Chapter 10.
1.3 Our 2008 plan
This is not the first water resources plan we have produced. Every 5 years each water company
publishes a Business Plan following a very detailed review of all its future service and expenditure
needs, including those relating to water resources. Our economic regulator, the Water Services
3 Water Resources Planning Guideline (WRPG) (EA, November 2008)
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Regulation Authority, “Ofwat”, uses this information when setting price limits for the following five
years. The last review of price limits was completed in 2009 when Ofwat set price limits for the period
2010-2015.
As part of our preparation for the price-setting process, we submitted a Draft Water Resources
Management Plan to the Welsh Government in March 2008. Following a Direction from the Welsh
Government in January 2009, the Plan was published for consultation on 15 January 2009. The 2008
Draft Plan was also included as part of the Business Plan we submitted to Ofwat later the same year,
although its interim status was recognised given that it was still subject to consultation at the time.
The 2008 Draft Plan did not complete the full statutory process as it was never formally approved by
the Welsh Government. This was primarily due to fact that, in some respects, the Plan was overtaken
by events, in particular the need to consider the impact of the review of our consents that the
Environment Agency has undertaken in the light of the European Habitats Directive.
1.4 Other Developments since the 2008 Plan
As well as the impact of the Habitats Review of Consents, this Plan also takes into account other
significant developments since 2008. These include updated information – e.g. on demand (see
chapter 4), and the projected effects of climate change (see chapter 7) – and feedback on our 2008
Plan from our main stakeholders. Table 1.1 below presents a summary of the main points of
difference between this revised draft plan and our 2008 Plan: detail on each topic will be found in the
relevant chapters of the remainder of this document.
2008 Draft
Plan Revised Plan Reason for Change Chapter
Supply
demand
deficits
Six of our Water
Resources Zones were
previously forecast to be
in deficit and are now
forecast to be in surplus
during the planning
period. Three zones are
now presented as having
forecast supply deficits.
We have revised our demand forecasts and
leakage strategy. We have also reflected
the latest predictions about climate change
impacts (UKCP09) and taken account of
proposed modifications to some abstraction
licence modifications that may be needed to
meet the Habitats Directive.
4,6,7
Strategic
Environmental
Assessment
Fully updated
Different options have been assessed to
reflect changes in predicted supply and
demand in some zones.
Representations received from the
Countryside Council for Wales highlighted
several areas that required amending/
updating.
10
Habitats
Regulations
Assessment
Fully updated
Our Habitats Regulations Assessment now
incorporates the outcomes of the
Environment Agency‟s review of our
consents.
10
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
2008 Draft
Plan Revised Plan Reason for Change Chapter
Different intervention options have been
assessed to reflect changes in predicted
supply and demand in some zones.
Representations received during the last
consultation exercise from the Countryside
Council for Wales, Natural England,
Environment Agency and the Wye & Usk
Foundation highlighted several areas that
required amending/ updating.
Outage Allowances updated
Assumptions have been reviewed against
actual data. Outage review is a continuous
process.
3
Operational
Use & Losses Allowances updated
We have improved our data collection and
reflected the results of a detailed pilot study
of operational use at water treatment works.
3
Climate
Change Use of UKCP09
Updated projections of climate change for
the UK were produced in 2009 and analysed
in preparation for this plan.
7
Sustainability
Reductions Reductions incorporated
From our consultation on the 2008 Draft
Plan one of the main issues highlighted was
the exclusion of the Environment Agency‟s
proposed sustainability reductions because
they had not yet been notified to the
company. This Revised Draft takes full
account of the reductions.
6
Target
Headroom
Updated forecasting
around the demand
components of
Headroom. Full review
of headroom allowance.
The Environment Agency raised concerns
over large Headroom allowances in some
zones. We have fully reviewed our
uncertainty assumptions in these zones,
particularly those regarding climate change
5
Demand Demand forecast fully
revised and updated
Changes in demand forecasts caused by
effects of the current economic recession
and changes in the rebasing of the data
used in the forecasts from 2007-08 to 2008-
09.
4
Costing of
Options
Capital and operating
costs updated in line with
Welsh Water‟s Unit Cost
Database (UCD)
To ensure full consistency with Welsh
Water‟s investment programme, all aspects
of our Resource and Production schemes
have been reviewed and re-costed,
9
Environmental Additional categories To ensure a full assessment of the 9
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
2008 Draft
Plan Revised Plan Reason for Change Chapter
& Social Costs added to assessment environmental and social costs associated
with the implementation of water resource
schemes, we have ensured that all options
now use the same categories for
Environmental and Social costs
Carbon
Costing
Carbon emissions
updated
To ensure consistency with Welsh Water‟s
2010-2015 business plan all our resource
schemes‟ embedded and operational
emissions have been recalculated.
9
Table 1.1 – Updates since 2008 Draft Plan
1.5 Strategic Links
We operate in the broad policy framework that has been set by the Welsh Government. We have
tried to ensure that we have full regard to its key strategies and policies in preparing the plan. We
also work closely with the Environment Agency, and have discussed details of this plan with it,
particularly the effect its proposed changes to our licences because of the Habitats Directive. We
have also consulted with the Countryside Council for Wales and Natural England, particularly
regarding the Strategic Environmental Assessment and Habitats Regulations Assessment so we can
be confident that we have considered all the key environmental issues. We have summarised in Table
1.2 the main strategies and plans that have helped to shape our thinking in developing this document.
Organisation Document Links to this Plan
Welsh
Government
Strategic Policy Position
Statement on Water
(2011 update)
Sets out the Welsh Government‟s vision on how water
resources should be managed in Wales
Welsh
Government
Social and
Environmental
Guidance to Ofwat
Gives the Welsh Ministers‟ guidance to Ofwat on how it
should undertake its duties in relation to the Welsh
Government‟s objectives.
Welsh
Government
One Wales: One Planet
– The Sustainable
Development Scheme
of the Welsh
Government
We need to have due regard to the Welsh
Government‟s sustainable vision for Wales where
“land, freshwater and marine environment is best
managed to provide the services of food, wood, water,
soil, habitats and recreation”.
Welsh
Government
People, Places, Future:
The Wales Spatial Plan
2008 Update
The Spatial Plan aims to safeguard and protect Wales‟
natural and historical assets whilst enhancing their
resilience to climate change.
Welsh
Government
Climate Change
Strategy for Wales
The Welsh Government‟s vision on tackling climate
change in Wales and what it expects from industry.
Welsh
Government
Environment Strategy
for Wales
95% of internationally designated conservation sites to
be in favourable condition by 2010
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Organisation Document Links to this Plan
Welsh
Government
A Low Carbon
Revolution: The Welsh
Government Energy
Policy Statement
This policy statement sets out the Welsh Government‟s
ambitions for low carbon energy in Wales.
Welsh
Government
Planning Policy Wales
(Edition 3)
Sets out the land use planning policies of the Welsh
Government and the key policy objectives for Local
Development Plans in Wales which reflect the
sustainable development agenda.
Environment
Agency Wales
Water for People and
the Environment: Water
Resources Strategy for
Wales
Sets out how the Agency believes water should be
managed in Wales until 2050 and lists actions and
measures water companies should undertake to
achieve its Vision.
Environment
Agency Wales
Water Resources
Strategy for Wales –
First Action Plan
Sets out the required actions for the relevant parties to
deliver the Agency‟s Water Resources Strategy.
Environment
Agency Wales Regional Action Plans
Localised plans containing actions the Agency wants
water users to take to achieve their national strategy
aims.
Environment
Agency
approved by
Welsh Ministers
River Basin
Management Plans
How the Environment Agency will implement the
European Water Framework Directive and the
measures it wishes to implement for water bodies to
achieve “good status/ potential”.
Environment
Agency
Catchment Abstraction
Management Strategies
Sets out water resource availability status across
surface water/ groundwater catchments in England and
Wales. This determines the Agency‟s licensing policy.
Ofwat
Preparing for the future
– Ofwat‟s climate
change policy statement
Sets out Ofwat‟s expectation that companies will plan
for the impacts of climate change upon their supply and
demand balances within the water resource planning
framework.
Local Councils
Regional Development
Plans/ Spatial
Strategies
These set out Councils‟ aspirations for development in
their area.
Table 1.2 – External Strategies and Plans we have considered
1.6 Compliance with Welsh Government Direction
Throughout the preparation of this Plan we have complied fully with the joint Department for the
Environment, Food and Rural Affairs/ Welsh Government Water Resources Management Plan
Direction (2007). The specific Direction items are covered in the following report sections:
the planning period (item no. 2) - Introduction section;
the frequency of customer restrictions (planned and actual) (item no. 3a) – section 3.5;
the option appraisal methodologies (item no. 3b) – Chapter 9;
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
the requirement to undertake carbon accounting (item no. 3c) – section 9.4;
how account has been taken of climate change (item no. 3d) – Chapter 7; and
the estimation of household demand (item no. 3e) – section 4.4.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Chapter 2. Supplying Water in our area
This chapter provides factual background on our water supply area It explains some of the critical
issues we must consider and describes how our assets have been developed and managed to ensure
that we can provide a reliable supply of water to our customers.
2.1 Water resources in our supply area
Welsh Water delivers water supply services to most of Wales and some parts of England, including
most of Herefordshire. In total we supply water to around 3 million people, of which over 40% are
concentrated in the south east of Wales in the Cardiff and Newport area and much of the remainder is
located in the main population centres around the coast. These are in sharp contrast to the sparsely
populated areas of mid-Wales, where population densities are amongst the lowest in the UK.
Wales has a relatively wet climate when compared to other parts of the UK. We estimate that we only
use some 3% of rainfall, on average, for public water supply, which compares to 50% in parts of
South East England. However, the regional picture masks important geographical differences within
our supply area: for example, at up to 3,000mm per annum, rainfall in Snowdonia can be more than
four times the levels recorded in the border areas and Herefordshire, where 700mm per annum is
typical.
The diversity of our water supply systems reflects these regional variations. Most comprise discrete
small-scale local supplies, of which we have a considerable number, with only South East Wales
being served by the sort of large scale multi-source integrated network that is typical in many other
water company areas.
Our main sources of water are our 65 impounding reservoirs. These are linked closely to our five
major river regulation schemes: on the Rivers Wye and Usk in the south east of Wales; the Rivers
Tywi and Cleddau in the south west; and the River Dee in the north.
On average we abstract from the environment around 800 million litres a day (Ml/d) for public water
supply. This normally increases by around 15 - 20% during the summer. During periods of extreme
conditions – long hot summers or sudden thaws following freezing weather – the demands on our
supply systems can increase by over 25%, and in some localised areas by nearly 50%.
Figure 2.1 illustrates this variability and highlights the peaks in demand we experienced during the
warm summer of 2006 and the very cold period just before Christmas 2010.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Figure 2.1 – Variability of water volume put into supply
Underlying these short term variations is a long term steady decline in overall water demand (see
Figure 2.2). This is primarily due to the decline of heavy industry, particularly in South Wales, and the
significant reduction in leakage from our networks over the past fifteen years.
Figure 2.2 – Declining trend in water supplied
750
800
850
900
950
1000
Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar
Average Monthly Company Distribution Input (Ml/d)
2006-07 2007-08 2008-09 2009-10 2010-11
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Against this background, and notwithstanding a general perception that Wales has an abundant
supply of water, our future water supply strategy faces a number of challenges, as set out in the
remainder of this document.
2.2 Water Resource Zones - General
Our water supply area is divided into 24 Water Resource Zones (WRZs). These zones are defined as
the largest area in which all resources can be shared, and hence they represent a group of customers
who receive the same Level of Service. The WRZs essentially define the limits of the areas beyond
which water supply becomes increasingly uneconomic with the current supply infrastructure. The
landscape of our supply area means that each of these WRZs is fairly self-contained, and the scope
to move water between zones is extremely limited.
Figure 2.3 shows our 24 WRZs, of which the largest is the South East Wales Conjunctive Use System
zone (SEWCUS) which covers 40% of our customers, and the second largest is Tywi Gower, which
covers another 20%. By contrast, the 8 smallest zones together cover just 1.5% of our customers.
Table 2.1 below presents further details on each of the 24 WRZs.
Figure 2.3 – Water Resource Zones
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
WRZ No. WRZ name Area (km2)
Population served (‘000)
4 Water delivered (average, Ml/d)
5 Main Source of water
North Wales
8001 North Eyri Ynys Mon 1,336 121 41 Reservoir storage
8012 Clwyd Coastal 152 80 22 Reservoir storage
8014 Alwen Dee 1,142 155 45 Reservoir storage
8020 Bala 391 4 1 Reservoir storage
8021 Tywyn Aberdyfi 68 5 1 River abstraction
8026 Blaenau Ffestiniog 332 6 2 Reservoir storage
8033 Barmouth 85 5 2 Reservoir storage
8034 Lleyn Harlech 648 35 14 Reservoir storage
8035 Dyffryn Conwy 841 90 29 Reservoir storage
8036 South Meirionydd 584 7 Reservoir storage
South West Wales
8201 Tywi Gower 3,524 691 179 Reservoir storage
8202 Mid & South Ceredigion 1,780 62 18 Reservoir storage
8203 North Ceredigion 469 31 9 Reservoir storage
8206 Pembrokeshire 1,699 118 40 Reservoir storage
South East Wales
8101 Ross on Wye 198 19 6 Bulk supply import
8102 Elan Builth 1,229 18 5 Reservoir storage
8103 Hereford 1,258 127 32 River abstraction
8105 Llyswen 353 9 2 River abstraction
8108 Brecon Portis 447 12 4 Groundwater abstraction
8106 Monmouth 104 13 3 River abstraction
8107 Pilleth 366 8 2 Groundwater abstraction
8110 Vowchurch 250 6 2 Groundwater abstraction
8111 Whitbourne 354 15 5 River abstraction
8121 SEWCUS 2,756 1276 361 Reservoir storage
TOTAL 20,366 2915 829
Table 2.1 – Water Resource Zones – Key Facts and Figures
The following sections present further detail on each of our three sub-regions: North Wales, South
West Wales, and South East Wales.
4 Source: Table 10 June Return 2009
5 Based on average water delivered Table 10 June Return 2006 – 2009 with estimated zonal leakage included.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
2.2.1 Water Resource Zones - North Wales
The ten WRZs in North Wales serve half a million people living mainly in Chester and Deeside,
Anglesey, the Bangor and Caernarfon area and the north coastal strip from Llandudno to Prestatyn.
They also supply some large non-potable customers in the area, notably on Deeside.
The WRZs in North Wales vary from very small areas supplied entirely from run-of-river abstractions
to larger zones supplied from a combination of impounding reservoirs, run-of-river abstractions and
groundwater sources. Some parts of North Wales experience a significant influx of tourists during the
summer months, which increases the demand for water. As a consequence, the systems that supply
these areas have to be able to meet these peaks whilst operating at lower levels during the remainder
of the year. Rainfall across North Wales varies from upwards of 3,000mm per annum on the
mountains of Snowdonia to 1,200mm per annum around the coastline of North Wales and Anglesey.
The supply of water in North Wales may be significantly affected in the next few years by the potential
development of a major new power station at Wylfa on Anglesey. When finally confirmed, the power
station will require a substantial volume of water in a zone that is comparatively supply-constrained,
and this will alter the complexion of water resource planning in the area. Although these plans are not
sufficiently crystallised to be taken into account in this Plan, it is likely that they will be a central
feature in the next draft Plan, due in 2013.
2.2.2 Water Resource Zones - South West Wales
The WRZs across South West Wales serve 0.9 million people living mainly in Swansea, Llanelli,
Carmarthen and the coastal towns and villages from Pembroke to Cardigan. We also supply and
support several large non-potable customers in the Pembroke Dock/ Milford Haven area. Much of
South West Wales experiences a significant influx of tourists during the summer months, which
increases the demand for water.
Rainfall across South West Wales varies from a low of 1,047mm per annum at Nevern on the north-
west Pembrokeshire coast to a high of 2,220mm per annum in the uplands of the Rheidol valley in
Ceredigion. Rainfall in the main Tywi catchment averages around 1,600mm per annum.
The WRZs in the region can be divided into two categories; small zones with relatively simple supply
systems in the north west of the area (eg. North Ceredigion and Mid & South Ceredigion) and the
more complex conjunctive use zones in the southern part of the region (eg. Pembrokeshire and Tywi
Gower).
One of the most significant zones in South West Wales – Pembrokeshire – is expected to require
investment to meet a supply-demand deficit during the Plan period. A diagram of the zone is
presented in figure 2.4 below.
Bolton Hill Water Treatment Works is fed from the Eastern and Western Cleddau and supplies water
to the southern half of the zone including Haverfordwest, Pembroke, Milford Haven and Tenby.
Preseli Water Treatment Works, fed from Llys-y-fran Reservoir and the Eastern Cleddau (via
Rosebush Reservoir), supplies the northern, more rural area and can also be used to supply water
into Haverfordwest.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Figure 2.4 – Pembrokeshire
2.2.3 Water Resource Zones - South East Wales
The WRZs across South East Wales serve 1.5 million people living mainly in Cardiff, Newport and the
South Wales valleys. They also serve several large non-potable customers.
Rainfall across South East Wales varies from as little as 700mm per annum in the eastern parts
around Hereford to some 2,200mm per annum in mid-Wales and the uplands of the South Wales
valleys. The main lowland urban areas such as Cardiff receive around 1,200mm per annum, slightly
under the average for Wales.
Within this sub-region, the South East Wales Conjunctive Use System zone (SEWCUS) is our largest
and most complicated WRZ. As set out in chapter 8 significant investment may be required in this
zone during the Plan period.6 A schematic diagram of SEWCUS is presented in Figure 2.5 below.
6 One other small zone in the South East also requires minimal investment, but this is negligible by comparison.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Figure 2.5 – The South East Wales Conjunctive Use System SEWCUS
There are several upland raw water reservoirs in the Brecon Beacons that can feed this zone,
including: Talybont (shown in Figure 2.6 below, capacity 11,668 Mega Litres) which supplies the Usk
Valley communities of Crickhowell and Abergavenny; Pontsticill (capacity 15,753 ML) which supplies
areas of the South Wales Valley; and Beacons/Cantref/Llwynon (total capacity 8,572 ML) which
supply Merthyr Tydfill and the area south towards Cardiff.
The other major sources of raw water are the Rivers Usk and Wye. The former is used to fill
Llandegfedd Reservoir (capacity 23,609 ML) near Cwmbran which in turn feeds Sluvad Water
Treatment Works. It can also feed Sluvad and Court Farm Water Treatment Works directly. The River
Wye is used to supply Court Farm Water Treatment Works. These Water Treatment Works feed the
main urban areas of Newport and Cardiff.
In addition there are a number of smaller reservoirs and Water Treatment Works that can supply
water in this zone.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Figure 2.6 – Talybont Reservoir
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Chapter 3. Water Supply Capacity
The purpose of this chapter is to set out how we calculate the amount of water we can supply in each
WRZ. This is a function of the “Deployable Output” of our water resource assets together with the
allowances and adjustments that are made for the operational losses that are inherent in the
treatment and of water,7 outages, and transfers.
3.1 Deployable Output
Deployable output (DO) is the maximum quantity of water from a source, a group of sources, or from
a bulk supply, that can be sustained during a Dry Year. Output can be constrained by:
abstraction licence conditions;
the capacity of assets (pumping stations, treatment works, mains);
water quality factors; or
environmental needs, for example freshet releases.
We have assessed Deployable Output in accordance with Environment Agency guidelines and best
practice methodologies8 and have specifically carried out in-depth modelling to re-assess Deployable
Output in the 15 of our 24 WRZs where the supply system is complex. In the other 9 WRZs this has
not been necessary, either because the zone is served by a simple, single source, or because
Deployable Output is effectively capped by abstraction licence conditions.
For the modelling of the 15 complex zones we have used our “WRAPSim” software. This tool
examines how well a water supply system would perform in meeting demands under a variety of
historical climatic conditions and seeks to optimise the operation of the system.
A complete re-assessment of Deployable Output for all zones was undertaken during the preparation
for the 2008 Draft Plan. The key activities involved in this were:
an up-to-date review of the operational network and constraints;
a review of our demand modelling, and peak demand in particular: high peak demand during
the summer can limit Deployable Output later in the year;
a complete re-evaluation of the information available on reservoir inflows, including a review
of all available historical data and the identification of the most appropriate source of
information on inflows for use in the planning process;
update of the model data on inflows to 2007 where available;
the development of eight new rainfall-runoff models and improvements to existing ones; and
7 Losses from the distribution system are part of leakage and are included in “demand”, as described in chapter 4 below.
8 Surface Water Yield Assessment (National Rivers Authority, 1995); Reassessment of yield methodology (EA, 1997); A Unified
Methodology for Determination of Deployable Output from Water Sources (UKWIR and EA, 2000).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
a re-assessment of the Emergency Provision requirements.9
The notable feature of this work was the analysis of 2006 demand. Although overall demand for
water in 2006 in Wales was considered to be normal, most WRZs experienced exceptional peak
demands. We have built these unusual demand patterns into our projections going forwards.
We set out the methodologies used in the re-assessment of Deployable Output in our 2007 June
Return to our economic regulator, Ofwat. Comments made by the Environment Agency in November
2007 have been addressed as part of our ongoing dialogue with the Agency and have been reflected
in our technical work as appropriate.10
In addition, since November 2007, we have continued to update the following components:
our assessment of peak demands, and how they relate to normal demand;
reservoir and catchment inflows, following updates of Environment Agency data; and
the baseline models we use to incorporate the actions and triggers defined as “actions” in our
Drought Plan.11
This is in line with our Company policy on Level of Service and is in
accordance with Environment Agency methodology.
We will continue to update and refresh our planning tools to reflect up-to-date experience, notably the
drier than average conditions that characterised the early summers of 2010 and 2011.
3.1.1 Groundwater Sources
A review of groundwater source yields has also been completed in accordance with national best
practice guidelines.12
As a result of the natural landscape and geology of Wales, groundwater
accounts for just 5% of the total water supplied. Most groundwater sources are operated
conjunctively with surface water sources and are used intermittently. However, some small sources
are always in use and provide constant supplies to local areas that cannot be supplied by other
means.
3.1.2 Emergency Storage
An emergency storage allowance has been incorporated into our Deployable Output assessments, in
accordance with Environment Agency methodology. This provides the reserve of water that is
considered necessary in view of the uncertainty regarding the duration and severity of droughts. The
emergency storage allowance adopted has been set at 30 days, which is in the middle of the range
(15-45 days) suggested by the Environment Agency guidance.
3.1.3 Dead Storage
Dead storage is the volume of water in a reservoir that lies below the lowest draw-off point and
therefore cannot be abstracted under normal operating conditions. A review of dead storage
9 As set out in the EA‟s 1997 “Re-assessment of Water Company Yields”.
10 See, in particular, “Deployable Output Values for Draft 2007 Water Resources Management Plan (WRAPSim modelled
zones)”: Entec, November 2007. 11
Final Drought Plan (DCWW, 2009, awaiting Direction to publish from WG). 12
The Methodology for the determination of outputs of groundwater sources (UKWIR, 1995b); A methodology for the determination of Groundwater Sources (UKWIR, 1995); Critical Period Groundwater yield (UKWIR/EA 2001).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
allowances has been undertaken using data collected from bathymetric surveys and the results have
been incorporated in the Deployable Output calculations. Appropriate linkages with the Drought Plan
have been made where it is considered that dead storage may be used in drought conditions.
3.2 Resource Developments during 2005-2010
As part of the re-assessment of Deployable Output, we identified a number of capital schemes which
would improve the security of water supplies and bring about improvements. These schemes include
those originally identified in anticipation of our 2005-2010 investment programme and a number of
additional resource schemes that were implemented during that period. These are detailed in Annex
1.
3.3 Other changes since the 2008 Draft Plan
With three exceptions, there have been no further updates to our assessment of Deployable Output
since the 2008 Draft Plan.
First, we found that the efficiency of the abstraction from Llys-y-Fran reservoir could be improved,
increasing the Dry Year Annual Average Deployable Output from 77 Ml/d to 79.12 Ml/d. Details are
set out in the supporting technical report.13
Second, prompted by the dry summer of 2010, a number of operational measures were taken in the
SEWCUS WRZ to ensure continuity in the provision of services to all our customers. These changes,
mainly relating to network configuration, were incorporated into the SEWCUS WRAPSim model and
the annual average Deployable Output increased from 465 Ml/d to 477 Ml/d as a result. Details are
set out in the supporting technical report.14
Third, following the completion in March 2009 of a scheme in North Eyri Ynys Mon to improve security
of supply, details of the final delivered outputs of the project were incorporated into the WRAPSim
model, which had previously relied on theoretical design information. Annual average Deployable
Output decreased from 52.8 Ml/d to 51.0 Ml/d as a result.15
3.4 Outage
3.4.1 Background
Outage is defined as the temporary loss of Deployable Output due to planned and unplanned events
in a Dry Year (or drought period). An allowance for outage is required in order to recognise that at
any given time some assets will temporarily be out of action for one reason or another. It is important
to estimate outage for each WRZ individually: this is done by taking a pragmatic view of the potential
future reduction in Deployable Output that could be caused by asset failures and/ or operational
problems.
The estimation of outage is based on records of past events which resulted in a loss of Deployable
Output O and an assessment of the risks of unplanned events occurring in the future. We have used
13
“2010 Review of Consents Supply Assessment in Pembrokeshire Water Resources Zones, Final Report” (Entec, Jan 2011).
14 “2010 Review of Consents Supply Assessment in SEWCUS Water Resources Zones, Final Report” (Entec, Jan 2011).
15 “North Eryri Ynys Mon WRAPSIM changes to DO Model”: Welsh Water, October 2010.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
best practice UK Water Industry Research (UKWIR) methodology16
in accordance with the
Environment Agency‟s Guideline, to determine the outages for all of our WRZs.
3.4.2 Our estimation of outage
Since 2005 we have gathered outage data on a monthly basis at Water Treatement Works level,
classified in accordance with the six main categories set out in the UKWIR report. This enables us to
carry out an annual assessment of outages and their causes. The six categories are:
algae – where this may be present in the raw water, affecting quality at source;
planned outage – these are known planned maintenance activities, and are divided into those
that would take place even in a drought situation and those that could be delayed until a non-
drought period;
power failure – this highlights areas where temporary and back-up generation is not adequate
to maintain operation;
source pollution – where, for example, there is a risk that a river could be contaminated due to
a spillage;
system failure – events where equipment has failed; and
turbidity – again, affecting raw water quality.
The methodology we use assesses the probability of events occurring by looking at the duration and
magnitude of observed events; we have modified this by adding information on the frequency with
which these events occur. The monthly data we collect are fed directly into this assessment.17
The
final outage estimate derived from this process is ultimately presented as a reduction in Deployable
Output. We have assessed outage at WRZ level for both annual average and critical period18
scenarios.
In assessing outage, we ensure that there is no double counting of Water Treatement Works losses
or operational use that is accounted for elsewhere. As part of updating our analysis, we found that
some double-counting had previously occurred in relation to turbidity which, as well as being
accounted for in outage, had been identified as a cause of significant higher operational use
associated with increased filter washing caused by greater turbidity. Consequently, our assessment
of outage has been reduced in some WRZs.
3.4.3 Changes since the 2008 Draft Plan
Since publication of the 2008 Draft Plan we have carried out a two-stage review of outage to take
account of new evidence from the monthly data collection exercise.
In Stage 1 we compared the estimates and assumptions on which our outage assessment was based
against actual up-to-date evidence, and made adjustments where significant differences were
observed, taking into account Dry Year influences where appropriate. We also considered allowing
16
“Outage Allowances for Water Resource Planning”: (UKWIR, 1995). 17
“Review of Outage Assumptions for Post Draft Water Resources Management Plan”: November 2008 Entec, 2009. 18
This is the period of peak demand within the Dry Year.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
for events that were considered possible even if there had been no actual occurrence during the
period over which monthly data had been collected.
In Stage 2 we examined our Drinking Water Safety Plans and the risks identified within them relating
to source pollution. Where there is a risk of source pollution that had not been captured using the
actual events database, our outage assessment was amended accordingly.
Our outage calculations have been updated in this Plan for those WRZs that have been subject to
reductions in Deployable Output as a result of implementing the outcomes of the Environment
Agency‟s consent review exercise: outage has also been updated for North Eyri Ynys Mon zone
because this is the other significant WRZ there has been a re-assessment of Deployable Output.19
3.5 Levels of Service (LoS)
A key role in Water Resources Planning is played by the frequency with which a hosepipe ban or a
Drought Order/ Permit would be expected to be required in order to maintain water supplies, the
“Level of Service”.
We believe that it would be wrong for us to plan for a level of service that would guarantee there
would never be any customer restrictions as this would require enormous investment in additional
water resource assets (principally reservoirs) which would be used very infrequently. This would
require much higher levels of customer bills, which we do not consider could be justified, and would
be environmentally unacceptable.
The Company has accordingly set its minimum overall level of service as follows:
not more than once in every 20 years, on average, for a hosepipe ban, and
not more than once every 40 years, on average, for Drought Orders/ Permits.
We view the imposition of rota cuts and standpipes, which represent more severe restrictions on
customer use, as unacceptable. This is for several reasons, notably the risk to public health that rota
cuts and standpipes entail.
In practice the actual current level of service in each of the 24 WRZs varies and is shown in Table 3.1.
To ensure compliance with the Water Resources Management Plan Direction (2007) and as
requested by the Agency in their Statement of Response Advice Report to the Welsh Government on
our 2008 Draft Plan, for each WRZ we have assessed the impact of each resource option upon the
level of service. We have ensured that all intervention options are compliant with our current level of
service and the reported increases in DO reflect this. However, where appropriate, changes to level
of service as a result of the options have also been considered.
It is theoretically possible to increase the Deployable Outputin a zone by lowering the level of service.
Changes to our overall level of service are therefore one of the options when we are considering how
to address supply demand deficits.
19
“R143 NEYM outage update Nov 2010” Entec UK Limited, November 2010.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Water Resource Zone Levels of Service
20 (years)
Hosepipe Ban Drought Order/ Drought Permit
8001, North Eyri Ynys Mon 1 in 24 >1 in 48
8012, Clwyd Coastal 1 in 22 1 in 43
8014, Alwen – Dee 1 in 29 1 in 43
8020, Bala >1 in 84 >1 in 84
8021, Tywyn – Aberdyfi >1 in 48 >1 in 48
8026, Blaenau Ffestiniog 1 in 24 1 in 48
8033, Barmouth 1 in 48 >1 in 48
8034, Lleyn – Harlech 1 in 24 1 in 48
8035, Dyffryn – Conwy 1 in 29 1 in 86
8036, South Meirionnydd >1 in 48 >1 in 48
8101, Ross on Wye >1 in 33 >1 in 33
8102, Elan – Builth >1 in 33 >1 in 33
8103, Hereford Conjunctive Use System >1 in 33 >1 in 33
8105, Llyswen >1 in 33 >1 in 33
8106, Monmouth >1 in 33 >1 in 33
8107, Pilleth >1 in 33 >1 in 33
8108, Brecon – Portis >1 in 33 >1 in 33
8110, Vowchurch >1 in 33 >1 in 33
8111, Whitbourne >1 in 33 >1 in 33
8121, SEWCUS >1 in 33 >1 in 33
8201, Tywi Conjunctive Use System 1 in 36 >1 in 36
8202, Mid & South Ceredigion 1 in 23 >1 in 69
8203, North Ceredigion 1 in 35 1 in 69
8206, Pembrokeshire 1 in 36 >1 in 36
Table 3.1 – Actual Level of Service
20
Note that “> 1 in 33” denotes a better level of service than 1 in 33, not a frequency that is greater than 1 in 33. Also, it should be pointed out that “>1 in 33” refers to those situations where we have records for the last 33 years, during which there have been no restrictions.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
3.6 Operational use of water
Water can be lost during the routine operation of raw water mains and water treatment works. Overall
we estimate some 3% of water is lost in this way.
3.7 Water Transfers
3.7.1 Potable supplies
There is some limited scope to transfer water, both raw and treated, between particular parts of zones
in our area and in the form of bulk supplies between ourselves and neighbouring water companies. A
summary of our transfers is shown in Table 3.2.
Export from Import to Maximum Volume
(Ml/d)
Alwen Dee WRZ Dee Valley Water 0.16
Lleyn Harlech WRZ* Barmouth WRZ 1
Severn Trent Water South Meirionydd WRZ 0.45
South Meirionydd WRZ Severn Trent Water 0.12
Severn Trent Water Ross-on Wye WRZ 9
Hereford WRZ* Whitbourne WRZ 0.33
Hereford WRZ* Ross on Wye WRZ 1
Tywi Gower WRZ SEWCUS WRZ 14.08
*Schemes delivered in AMP4 to increase inter-zonal transfer capability
Table 3.2 – Water Transfers
Further details of three of these transfers are provided below.
Tywi Gower to SEWCUS
Our latest assessment of the maximum level at which water can be transferred from Tywi Gower to
SEWCUS is based on WRAPSim modelling that takes into account changes made to the supply
system following the dry summer of 2010 (as described in section 3.3 above) and confirmation of the
capacity of the network to deliver transfers at a higher level. This is one of the reasons for the change
in Deployable Output for the South East Wales Conjunctive Use System, “SEWCUS”, described in
section 3.3 above.
Alwen Dee to Dee Valley Water
The River Dee is a regulated source that is managed in accordance with the Dee General Directions
which are the responsibility of the Environment Agency, supported by the three major water
companies in the area (Welsh Water, Dee Valley, United Utilities) and British Waterways Board. As
part of this complex arrangement we also export a small amount of water to Dee Valley Water in the
lower part of the Dee system which enables them to supply domestic properties in that area.
Severn Trent Water to South Meirionydd
The landscape of South Meirionydd WRZ and the limited small-scale supplies in the area can make
supplying water a challenge. Hence, it is beneficial to both us and Severn Trent Water (whose supply
boundary is on the border with the South Meirionydd WRZ) to have an “exchange” of water in certain
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
locations. There is an import into the zone from Severn Trent Water of 0.45 Ml/d, and an export from
the zone to Severn Trent Water of 0.12 Ml/d.
3.8 Elan Builth
Since the 2007 June Return we have modified the reporting of Elan Builth WRZ so as to show only
the Welsh Water abstraction allowance (around 5 Ml/d) within this zone and not the significantly
greater proportion exported to Severn Trent Water (up to a maximum of 386.4 Ml/d) from the Elan
reservoirs. This amendment was agreed with the Environment Agency for the 2008 Draft Plan and
removed any discrepancy relating to the reporting of Deployable Output of a Severn Trent source
which is within their, and not our, control.
3.9 Non-Potable Supplies
In addition to supplying domestic and non-domestic customers with potable water, we do in certain
instances and locations supply large industrial users with water that has not been treated to potable
standards but that is suitable for their purposes. There are two zones where these supplies share
water resources assets with potable water supply systems and where the non-potable supplies are
relevant to the calculation of Deployable Output.
Pembrokeshire WRZ
In this WRZ we supply a number of industrial users of water in and around the Milford Haven area,
mostly involved in the oil refinery, natural gas and power generation industries. The water is primarily
used for tank cleaning and cooling purposes. The supply of non-potable water is taken account of
directly within Deployable Output in this zone, as both potable and non-potable supplies are drawn
from the same raw water source. At present the supply of water for industrial purposes equates to
approximately 27 Ml/d.
The South East Wales Conjunctive Use System (SEWCUS) WRZ
We also supply non-potable water to industrial customers in the SEWCUS zone. As in
Pembrokeshire, this water is directly accounted for within Deployable Output as it is primarily supplied
from raw water sources that are also used for domestic supply.
3.10 Other customers
There are a number of other Industrial customers that are supplied with non-potable water through
discrete supply systems. These do not affect the supply demand position in any of our WRZs
because they do not share assets with potable water supply systems and therefore do not affect
Deployable Output. Further details of these supplies are reported to Ofwat and the Environment
Agency on an annual basis.
We also provide a non-potable bulk supply to Albion Water. This water is not accounted for within our
supply demand balance for the Alwen-Dee WRZ because the supply system currently shares no
assets with our potable supply systems (although the non-potable resource could fairly readily be re-
deployed for potable use if necessary in the future).
3.11 Water Available for Use
Water Available for Use is defined as the volume of water available once we have adjusted
Deployable Output for outage, transfers and operational losses, and provides the figure we use for
planning purposes as the amount of water we can expect to be able to supply. It is Water Available
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
for Use that provides the figure that, if exceeded by the sum of Demand and Target Headroom (see
below) signifies that a zone is in deficit.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Chapter 4. The Demand for Water
This section provides a summary description of how we compile forecasts of the demand for water.
We begin by establishing a baseline position and then, by looking at factors such as projections of
population and household occupancy, we calculate how demand for water may change.
Full details of how we have prepared our demand forecasts can be found in our Technical Report,
Demand for Water Resources 2010.21
4.1 Baseline demand
Baseline demand forecasts include our current demand management policies (Section 4.6) but
exclude the effects of any additional demand management measures identified by the option
appraisal (Chapter 9). This approach is in full accordance with the Environment Agency guidance
(2008).
For the purposes of preparing our demand forecasts we chose 2008-09 as the base year, as this was
the latest year for which actual data was available when we embarked on the planning process. In
line with Agency guidance (2008) though, the years 2006-07 and 2007-08 have been retained and
shown in the supporting Water Resource Planning Tables to enable comparison between the 2008
Draft Plan, this Plan and the expected Final Plan.
4.1.1 Base Data – population and properties
Base year population for each WRZ was derived by adding one year‟s growth to 2007 estimates,
verified by reference to data published in 2008 by the Office of National Statistics and the Welsh
Government.
Base year property numbers are as reported in our 2009 June Return to Ofwat, and are derived from
extracts from Welsh Water‟s Customer Accounting System. Using information on customer
addresses, we are able to allocate properties to WRZs, categorised into measured, unmeasured,
households and non-households.
Occupancy rates are based upon a 2003 customer survey, supplemented by an annual zonal review
based upon metered consumption data and additional data obtained from customers as part of meter
option requests. In some areas the number of second homes is high and it is necessary to take this
into account.
To establish base year consumption for each customer type we use data from our Domestic
Consumption Monitor22
. The primary purpose of the Monitor is to enable our Company to determine
unmeasured household Per Capita Consumption. During 2008-09, Welsh Water undertook a review
of its current unmeasured Per Capita Consumption strategy. A revised strategy was developed to
build upon the existing monitoring areas to improve the geographical representation of the Domestic
Consumption Monitor. This will provide more robust estimates of unmeasured Per Capita
Consumption in the 24 WRZs in the future. Work has begun to select additional monitoring areas
21 “Technical Report, Demand Forecasts for Water Resources Plan 2010”: Welsh Water, 2010. 22 Our Domestic Consumption Monitor involves recording the consumption pattern of a fairly large number of homes over an
extended period of time. The aim is to produce a quantitative understanding of water consumption for various household types. The large number of houses and time period of the monitor allow trends and seasonal patterns to be investigated. Our DCM complies with Industry Best Practice.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
following a best practice review23
to bring the total number in the Domestic Consumption Monitor up to
approximately 150. As part of this process, the current areas will also be reviewed to ensure that they
comply with the UK Water Industry Research „best practice‟ guidance and thus remain suitable for
inclusion in the Domestic Consumption Monitor.
4.1.2 Unmeasured Per Capita Consumption (pcc)
For 2008-09, the regional annual average unmeasured Per Capita Consumption was derived from 15-
minute logged data from the Domestic Consumption Monitor with a total population of 66,554 in
unmeasured households. There has been no change to the methodology used to calculate
unmeasured Per Capita Consumption since the Draft Water Resource Management Plan was
published. However, to simplify the data collection and data checking processes and to allow for the
eventual addition of new monitoring areas, both the 15 minute flow data and base data are now input
to and processed in the corporate Leakage Monitoring and Reporting System software which
calculates the unmeasured Per Capita Consumption using the verified data.
Analysis of data from the Monitor produced an unadjusted annual average unmeasured household
Per Capita Consumption value of 154 l/h/d for the base year. After various adjustments, as set out in
on June 2009 Return to Ofwat (notably those made as part of the overall reconciliation of the water
balance) the figure we reported and have used as the basis for our demand forecasts is 160.1 l/h/d.
For each WRZ, unmeasured Per Capita Consumption was calculated by multiplying regional
unmeasured Per Capita Consumption by the ratio of measured Per Capita Consumption for the zone
to regional measured Per Capita Consumption. Measured Per Capita Consumption data from a single
year (2008-09) has been used to estimate ratios for each zone.
23
„Best Practice for Unmeasured Per Capita Consumption Monitors‟ (99/WM/08/25), UKWIR 1999
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
4.1.3 Measured Per Capita Consumption
Total measured water delivered (household and non-household) is constrained to reconcile with the
total volume derived from the income received.
The 2008-09 initial estimate of measured household Per Capita Consumption (as recorded) was
119.4 l/h/d. This was derived by dividing the consumption recorded by over 340,000 meters, adjusted
to reconcile with income, by the population in billed measured households. In the 24 WRZs, values
ranged between 109.6 l/h/d (Elan Builth) and 131.0 l/h/d (Whitbourne).
The average consumption per property in 2008/09 was 200 l/pr/day. This is 10 l/pr/day higher than the
equivalent 2006-07 figure. Consumption at property level is subject to more detailed analysis in which
trends in average consumption by groups of household types are tracked.
The corresponding estimate of measured household Per Capita Consumption for 2008-09, after
adjustments, was 124.2 l/h/d.
4.1.4 Non-Household Per Property Consumption
Non-household consumption is predominately measured, with only 10,000 properties (less than 1% in
terms of volume) remaining unmetered within our supply area. Our Compulsory Metering Policy is that
all non-household premises will be on a metered charge basis and these have been built into the on-
going metering programme. It is estimated that we will transfer around 500 properties per year on to
a metered basis. We derived the unmeasured non-household per property consumption estimate by
examining the consumption records of customers that have been compulsorily metered over the last
nine years. This produced a figure for 2008-09 of 487 l/pr/day.
4.1.5 Normalisation of Base Year
Finally, it was necessary to make adjustments to base year demand estimates to reflect the extent to
which the base year was not “normal”. Using regression techniques to explore the relationship
between consumption and weather (rainfall and temperature) we identified that 2008-09 was
comparatively wet, and adjusted the demand components upwards accordingly.
4.2 Population forecasts
4.2.1. Local Authority Projections
There are two projections of population available to us: one provided by the Welsh Government,
which is based on 2006 population estimates; and one provided by the Office of National Statistics.
These generate different figures for population growth, the first projecting an annual increase of
around 17,000 and the latter forecasting slower growth of 14,600 per annum. In accordance with
Government guidance24
on how to address this discrepancy we have used the Office of National
Statistics figures for total population and the Welsh Government projections to divide overall totals
between WRZs.
4.2.2 Migration
The biggest driver of population growth in Wales is likely to be inward migration. However, this is
expected to be slower in the short to medium term than the levels observed in recent years. Our
24
“Statistics for Wales – Local Authority Population Projections for Wales (2006-based) Summary Report”.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
projections therefore assume a lower level of migration over the next few years, returning to trend
after 2015.
4.2.3 Insets
An inset appointment is made where an existing supplier is replaced by another supplier of water or
sewerage services for customers in a specified area; an inset appointment can only be made for part
of a current supplier‟s area. Two inset appointments have been made in our water supply area, but it
is not possible to forecast the extent to which further inset appointments will be made in our area in
the future. However, from the point of view of water resource management planning, the important
point is that while insets will affect the number of customers we serve they will not affect our demand
forecasts because we will almost certainly still supply the water. We have also assumed that
household and customer demand characteristics will be unaffected by the making of inset
appointments.
4.2.4 Non-household Population
Non-household population (e.g. resident in prisons, university campuses, military bases) is forecast to
rise slowly, directly in line with the increase in the level of non-household properties forecast for the
period.
4.2.5 Population Forecasts
Future estimates of population in metered households are based on forecast numbers of new
properties, optant,25
and selectively metered households, multiplied by projected occupancy rates.
Similarly, average occupancy rates in non-household properties are multiplied by the number of
forecast non-household properties. The remaining population from the overall population forecasts is
allocated to the unmeasured household stock.
25
Customers who have chosen, or opted, to be metered.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Figure 4.1 shows the historical and projected population forecasts for the different customer
categories.
Figure 4.1 – Population Forecasts
4.3 Property Forecasts
4.3.1 Projections
We have based our forecast of the rate of change in the number of household properties within our
area on trends from the last 9 years. We estimate that there will be 9,000 new household
connections in a “normal” year. However, given the current state of the regional economy we are
currently experiencing lower new connection rates, and have reflected this in our near term forecasts.
From 2012-13 we forecast the level of new households built in our region to return to normal levels,
and over the ten years 2015-25 we are forecasting an element of “catch-up”, with new household
connections increasing above the long term normal level for a temporary period.
4.3.2 Government Statistics on Property Numbers
In June 2009, the Welsh Government published household projections for Wales at a National and
Local Authority Level. In addition, a number of Local Authorities have published Local Development
Plans. Our property forecasts for the 2008 Draft Plan for the Herefordshire area were based on
information received from Hereford County Council. Our revised forecasts take account of the latest
revisions to the Regional Spatial Strategies.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
4.3.3 Insets and Non-households
As mentioned earlier there may be a trend to customers in new properties in Wales being served by
inset appointee companies, but we nonetheless include these in our forecasts, because we expect to
have to supply them with water, whether directly or through an intermediary.
The level of non-household properties is forecast to continue to rise slowly throughout the planning
period at a steady rate of 200 properties per year. The already low level of unmeasured non-
households is forecast to continue to fall over the planning period.
4.3.4. Metered/ Unmeasured Split
The proportion of household customers on a metered supply will continue to rise. All new
connections to our network are required to be metered and we continue to see unmeasured
customers opting to have a meter installed at a steady rate. Overall, we estimate that the number of
customers opting to be charged on a measured tariff will continue at 2.5% of the number of
households remaining unmeasured at the start of each year.
Figure 4.2 shows historical and projected household forecasts for the period 2000-01 to 2034-35.
Figure 4.2 - Household property forecasts
4.4 Household Demand
Figure 4.3 shows the historical and projected household demand forecasts for the period 2000-01 to
2034-35, for both the normal and Dry Year forecasts. The shape of this curve reflects the interaction
between the upward pressure on demand caused by population and property growth, and the
downward pressure on demand caused by metering. The margin between Dry Year and normal
demands varies from zone to zone, but averages across our region at approximately 4%.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
„Normal‟ year forecasts of unmeasured and measured household demand were calculated by
multiplying together the forecasts of population and Per Capita Consumption. The zonal Per Capita
Consumption forecasts applied were derived by multiplying the regional forecasts by the zonal
unmeasured and measured Per Capita Consumption ratios (section 4.1).
Figure 4.3 - Household Demand Forecasts
4.5 Non Household Demand
4.5.1 Economic Sectors
We have been monitoring the measured water consumption of 13 sectors of economic activity for
over 12 years, and use this data as the basis for forecasts of future demand, as well as for other
purposes such as the estimation of night use allowances in leakage reporting.26
4.5.2 Non-household Demand
Our forecasts of non-household measured water delivered have been made by extrapolating past
trends. Our analysis of demand by sector has now been in place for over 10 years and provides a
basis for forecasting that we consider to be at least as robust as the approach used previously under
which consumption was defined as a function of future changes in economic conditions.
Longer term forecasts of non-household demand are notoriously difficult to make. In the demand
forecasts prepared for the Plan, we are forecasting that the rate of decline in demand will gradually
slow after 2014-15. There have been some large reductions in non-household demand in recent
26 NB: as a result, the WRP8 tables for the Revised Draft Plan will be completed using the Company‟s own sector headings
rather than those specified by the EA. However, in broad terms the headings are very similar.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
years but we believe that the levels reached towards the end of the planning period are approaching a
long-term minimum.
Figure 4.4 presents our forecasts of non-household demand for both the normal and Dry Year
scenarios.
Figure 4.4 – Non Household Demand Forecast
4.6 Distribution Input
Normal year forecasts of Distribution Input27
were derived by summing the Component forecasts
described in the previous sections and adding forecast total leakage to produce forecasts for each of
the 24 WRZ‟s for each year up to and including 2034-35.
„Dry‟ year and „Critical Period‟ forecasts for the 24 WRZ‟s were derived by applying „peaking‟ factors
to the Normal year forecasts to account for the expected increase in demand in whole „dry‟ years and
during shorter (for example, one week) periods of increased demand (Critical Periods). Our peaking
factors have been derived from analysis of demand data from 2002 to 2007. Since this is currently our
most accurate period of demand data, any attempts to lengthen this record to match the longer
hydrological records (typically from the early 1970‟s) would introduce great uncertainty into the
results.
Analysis undertaken within the demand forecast report also confirmed that 2003-2006 events used at
zonal level were dry year events and have been selected accordingly depending upon the zone. As
agreed with the Agency, this record will be improved as more data becomes available and/ or when a
dry year event occurs which would trigger a re-assessment of demand. For example, during 2010 we
experienced a significant prolonged period of dry weather. Analysis of this data and its impact on
water demand will commence shortly.
27
This is the volume of water, whether expressed on a zonal or company basis, that is delivered into supply, into the distribution
network.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Further results and peaking factors for each zone and the analysis process are discussed in detail in
our demand forecasting report21
.
Figure 4.5 shows the historic and projected distribution input forecasts for the period 1992-93 to 2034-
35 for both the normal and dry year forecasts. Tables 4.1 and 4.2 show the „Dry‟ and „Critical Period‟
forecasts for all 24 WRZ‟s for the years 2014-15, 2024-25, 2034-35. The 2008-09 values are actual
Distribution Input values as reported in our 2009 June Return to Ofwat.
Figure 4.5 Distribution Input Forecasts
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Zone No. Zone 2008-09 (Ml/d)
2014-15 (Ml/d)
2024-25 (Ml/d)
2034-35 (Ml/d)
8001 North Eryri/ Ynys Mon 40.84 37.10 36.11 35.76
8012 Clwyd Coastal 21.68 20.23 20.35 20.78
8014 Alwen/ Dee 44.62 45.29 42.94 42.05
8020 Bala 1.33 1.43 1.42 1.44
8021 Tywyn Aberdyfi 1.26 1.28 1.26 1.27
8026 Blaenau Ffestiniog 1.83 1.76 1.78 1.82
8033 Barmouth 1.62 1.69 1.73 1.80
8034 Lleyn/ Harlech 13.60 12.42 12.27 12.32
8035 Dyffryn Conwy 29.51 29.20 28.93 29.19
8036 South Meirionnydd 2.62 2.40 2.46 2.54
8101 Ross-on-Wye 5.95 6.33 6.49 6.77
8102 Elan/ Builth 4.67 5.05 5.13 5.27
8103 Hereford CU Area 32.53 37.71 38.07 39.70
8105 Llyswen 2.38 2.57 2.73 2.90
8106 Monmouth 3.49 3.77 3.87 4.00
8107 Pilleth 2.52 2.55 2.63 2.73
8108 Brecon/ Portis 3.98 4.79 4.81 4.90
8110 Vowchurch 2.24 2.41 2.48 2.60
8111 Whitbourne 4.77 5.33 5.48 5.71
8121 SEWCUS 361.27 352.33 353.19 363.12
8201 Tywi CU Area 178.76 180.69 180.15 183.99
8202 Mid & South Ceredigion 18.47 17.92 18.25 18.68
8203 North Ceredigion 8.62 9.42 9.71 10.02
8206 Pembrokeshire 40.20 42.09 41.74 41.97
Region 828.75 825.75 823.97 841.33
Table 4.1 Zonal Dry year Distribution Input Forecasts
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Zone No. Zone 2008-09 (Ml/d)
2014-15 (Ml/d)
2024-25 (Ml/d)
2034-35 (Ml/d)
8001 North Eryri/ Ynys Mon 40.84 43.61 42.44 42.04
8012 Clwyd Coastal 21.68 24.36 24.51 25.02
8014 Alwen/ Dee 44.62 56.35 53.43 52.33
8020 Bala 1.33 1.86 1.85 1.87
8021 Tywyn Aberdyfi 1.26 1.92 1.88 1.90
8026 Blaenau Ffestiniog 1.83 2.05 2.06 2.11
8033 Barmouth 1.62 2.89 2.96 3.07
8034 Lleyn/ Harlech 13.60 15.24 15.05 15.11
8035 Dyffryn Conwy 29.51 32.89 32.60 32.88
8036 South Meirionnydd 2.62 2.99 3.06 3.15
8101 Ross-on-Wye 5.95 8.11 8.31 8.67
8102 Elan/ Builth 4.67 6.47 6.58 6.75
8103 Hereford CU Area 32.53 46.23 46.68 48.68
8105 Llyswen 2.38 3.08 3.27 3.48
8106 Monmouth 3.49 4.42 4.53 4.70
8107 Pilleth 2.52 3.13 3.24 3.37
8108 Brecon/ Portis 3.98 5.44 5.47 5.58
8110 Vowchurch 2.24 3.14 3.23 3.39
8111 Whitbourne 4.77 6.25 6.42 6.70
8121 SEWCUS 361.27 401.21 402.19 413.50
8201 Tywi CU Area 178.76 220.01 219.35 224.02
8202 Mid & South Ceredigion 18.47 22.61 23.02 23.57
8203 North Ceredigion 8.62 11.36 11.71 12.08
8206 Pembrokeshire 40.20 55.13 54.67 54.97
Region 828.75 980.76 978.53 998.94
Table 4.2 Zonal Critical Period Distribution Input Forecasts
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
4.7 Managing Demand
Demand management plays a vital part in maintaining the security of water supplies, and can
contribute significantly to ensuring that water is managed in the most sustainable and cost effective
way.
This section describes the ways in which we look to manage demand, including water efficiency
strategy, leakage control, metering and tariff policies. Our baseline strategies for demand
management are built into the demand projections presented above.
4.7.1 Water efficiency
We have a duty to promote the efficient use of water by all our customers. To achieve this, we
provide information to customers about:
the sensible use of water in the home and garden;
how to conduct a self-audit of household consumption;
the availability of cistern and other water-saving devices;
the availability of supply pipe leakage detection/ repair;
how to report a leak; and
how to get further information.
Welsh Water launched its Water Efficiency Strategy in May 2007, building on an established water
efficiency programme and ensuring alignment with the Welsh Government‟s Environment Strategy
(Environmental Outcome number 14).
We believe that there is a need to move public perception away from thinking that Wales will always
have plenty of water and to encourage wiser and more efficient use of water. Our Water Efficiency
Strategy sets out the activities and initiatives that are in place and planned to promote the efficient
use of water. These include the provision of information to customers, as detailed above, and a
comprehensive programme of educational activities. In addition, our strategy fully reflects the
principles behind Ofwat‟s Water Efficiency Initiatives.28
There are 10 good practice headings within
the Register, and these are detailed below:
cistern displacement devices;
household water audits;
commercial water audits;
customer education/awareness;
other water efficiency initiatives;
metering;
water butts/composters/trigger hoses;
28
Water Efficiency Initiatives – Good Practice Register (Ofwat, 2007).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
retrofitting toilets and showerheads;
collaborative R&D (Research and Development); and
supply pipe repair/replacement.
A summary of our activities in each of these areas can be found in Annex 2.
4.7.2 Efficiency Targets
We have been promoting the efficient use of water by our customers for a number of years.
However, 2010 saw the introduction of mandatory targets by Ofwat and a notably more prescriptive
approach to what the promotion of water efficiency should entail.
We can choose to use water efficiency measures within our demand management strategy for a
specific water resource zone as part of our overall planning approach to water resource management
when the analysis indicates that it makes economic sense. If we use water efficiency measures as a
solution to address supply/demand issues then Ofwat monitors our progress in delivering them by
setting a “Sustainable Economic Level of Water Efficiency” target.
We are also obliged, through the newly-introduced Ofwat targets, to deliver a saving of 1.31 Ml/d
across the company in each reporting year. This is to be achieved through defined approaches to
water efficiency and is described as our “Base Service Water Efficiency” target.29
The Base Service
Water Efficiency element of water efficiency is separated into two further categories relating to the
mode of delivery, namely “Hard” and “Soft” option measures.
Delivering “Hard” options”
“Hard” measures relate to the installation or distribution of water-saving equipment. Such equipment
aims to reduce consumption by technological means. Under Ofwat‟s target mechanism hard
measures are permitted to contribute up to 70% of the overall target, which for us equates to around 1
Ml/d of water saved. The reason for this high percentage is that the evidence underpinning
technological measures for reducing water consumption is well-documented, and is regarded as
relatively robust.
To deliver these targets, we aim to deliver cost-beneficial savings across the entire customer base
whilst building on the evidence we compile to demonstrate the effectiveness of water efficiency.
During the first year of the target we have:
provided water-saving welcome packs to customers opting for a water meter;
undertaken a collaborative project with key stakeholders in Wales to understand the links
between water and energy efficiency and social behavioural change where affordability is a
key consideration;
provided water efficiency audits for schools and installed water-saving devices;
29
Ofwat‟s PR09/20 paper (December 2008) sets out its position on water efficiency and has set companies two-part targets;
base service water efficiency (BSWE) and the sustainable economic level of water efficiency (SELWE). The BSWE is the minimum activity Ofwat expects companies to undertake, whilst the SELWE is additional water efficiency activity above the base level.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
provided water efficiency audits and equipment installations in public health care sector
buildings, helping health authorities to manage their water footprint and reduce their costs;
assisted business customers with water audits and made recommendations for managing
water more efficiently, including help with the implementation of hard technological measures;
assisted tertiary education providers in managing their water consumption in places where
there is high demand, such as halls of residence;
collaborated in a UK-wide promotion with a major retailer and energy provider for the
distribution of free water-saving packs to customers;
provided free Hippo bags to all customers on request; and
provided a web-based water butt incentive scheme.
Throughout the remainder of our current 2010-2015 business plan period, we will continue to work to
identify the most effective approaches to water efficiency promotion across our customer base.
Linking “soft” and “hard” option measures
It is widely recognised that technology alone cannot deliver the optimal water efficiency strategy and
that other drivers of consumption such as behaviour, seasonality, culture and affordability influence
the demand for water. We are committed to ensuring that technological measures are supported by
“soft” approaches aimed at influencing individual or corporate use.
Delivering “soft” options
Soft option measures relate to the promotion of water efficiency through education or communication
programmes. Historically this is the approach to water efficiency promotion we have tended to use.
For example, during the recent “spring droughts” of 2010 and 2011 we moved quickly to reinforce the
message for customers to “use water wisely” through press releases, website updates, and so forth.
Within the mandatory targets, soft options can contribute the remaining 30% of the target. The lower
percentage recognises that the evidence of the effect that educational or communication campaigns
have on consumption is somewhat limited.
Overall, our education programme currently contributes around 90% of the 0.3 Ml/d annual reduction
required under the soft component of the mandatory target. We believe that this focus on education
is the most sustainable and cost-beneficial approach to the promotion of water efficiency.
4.7.3 Delivering our Water Efficiency Strategy
We have set up a Water Efficiency Working Group to deliver water efficiency projects: it is normally
held on a monthly basis.
We acknowledge the Ofwat mandatory target approach and, in accordance with the legislative
requirements in Wales, have consulted (in February 2009) with the Welsh Government as to how our
strategy for the promotion of water efficiency in Wales should be aligned with its overall sustainability
objectives.
It is our intention to maintain and to further the approach of promoting water efficiency through
communication and education in line with our current strategy whilst developing and expanding other
activities to ensure the year-on-year target reduction of 1.31 Ml/d continues to be achieved. Where
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
necessary, our strategy will be revised in the future in line with any new guidance issued by the Welsh
Government in relation to its sustainability objectives.
4.7.4 Leakage Strategy
With more than 27,000km of pipelines and more than 1 million customer connections on our network,
leakage is inevitable. It is critical for a water company to know how much water is leaking from its
assets and to have good operational knowledge of where that leakage is occurring.
We have an aged network, with many pipes over 100 years old. Fresh leaks are continually breaking
out; we require sustained leak detection and repair procedure simply to maintain leakage at current
levels. A substantial quantity of leakage is classified as “background leakage”, the aggregation of
losses from all the fittings on the network. These leaks are generally small and difficult to find, and
would usually be expensive to repair given the modest quantity of water saved.
We are committed to meeting our leakage targets and have reduced total leakage from 329 Ml/d in
2001-02 to 190 Ml/d in 2009-10, a reduction of 42% in 8 years. Detection, repair and optimisation of
leakage solutions are an integral part of the Environment Agency‟s Guidelines, primarily as a way of
reducing demand. The Guidelines state that we should:
demonstrate how the company‟s leakage appraisal is built from data on District Meter Area
source leakage and cost information to produce WRZ assessments of the Economic Level of
Leakage30 and thereby an overall leakage strategy at the company level;
detail the company‟s current leakage policies that are built into the baseline demand forecast;
and
not rely on a single assessment of ELL projected across the planning period.
Economic Level of Leakage
The Economic Level of Leakage can be broken down into Short Run Economic Level of Leakage or
Long Run Economic Level of Leakage, depending on which planning horizon is chosen. Short Run
Economic Level of Leakage is the leakage target to be achieved in the short term i.e. 5 years or so,
based on current leakage levels. The Short Run Economic Level of Leakage is updated in each five
yearly Periodic Review of water price limits to account for, for example, efficiency savings in the
previous 5 years. Our Short Run Economic Level of Leakage only includes current active leakage
policy activities and provides baseline leakage levels used in the demand forecasts across the
planning period.
For WRZs identified as being “in surplus”, Short Run Economic Level of Leakage and Long Run
Economic Level of Leakage values are equal. However, for deficit WRZs, the least cost planning
process identifies the least cost scheme(s) to meet the deficit. Such schemes may include further
reductions in leakage to levels below the Short Run Economic Level of Leakage, using more intensive
leakage control techniques or policies. If that occurs, the resulting leakage level in the zone is then
the Long Run Economic Level of Leakage and attainment of this target will require leakage reductions
below the Short Run Economic Level of Leakage either during or following the initial 5 year period.
30 ELL is determined as the point where the incremental benefit of additional leakage control is just offset by the incremental
cost of carrying it out i.e. it is not cost beneficial to undertake further leakage control as the cost of undertaking the work is greater than the equivalent cost of the „lost‟ water (that can be supplied from the other sources).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
In accordance with Ofwat guidance (Ofwat, 2008), the Economic Level of Leakage should now
correctly be referred to as the “Sustainable Economic Level of Leakage” in recognition of the fact
that the methodology should take account of the environmental, social and carbon-related costs and
benefits of leakage control, not just the water company‟s “private” costs and benefits. Since 2007 our
methodology for calculating Economic Level of Leakage has taken full account of these external
costs, and is therefore consistent with “sustainable” Economic Level of Leakage. The Economic
Level of Leakage targets for the whole company and by WRZ are shown in Table 4.2.
Zone 2010-11 (Ml/d)
2011-12 (Ml/d)
2012-13 (Ml/d)
2013-14 (Ml/d)
2014-15 (Ml/d)
Whole Welsh Water supply area
190.45 188.10 186.20 184.77 184.08
North Eryri/ Ynys Mon 8.55 8.16 7.83 7.56 7.37
Clwyd Coastal 4.55 4.37 4.23 4.10 4.02
Alwen/ Dee 7.48 7.57 7.65 7.71 7.76
Bala 0.48 0.48 0.48 0.48 0.48
Tywyn Aberdyfi 0.15 0.14 0.13 0.12 0.11
Blaenau Ffestiniog 0.51 0.59 0.59 0.59 0.59
Barmouth 0.37 0.37 0.37 0.37 0.37
Lleyn/ Harlech 3.64 3.53 3.44 3.36 3.31
Dyffryn Conwy 8.11 7.98 7.86 7.77 7.71
South Meirionnydd 0.75 0.72 0.69 0.67 0.66
Ross-on-Wye 1.55 1.51 1.48 1.46 1.45
Elan/ Builth 1.29 1.31 1.32 1.34 1.35
Hereford CU Area 6.91 7.11 7.29 7.46 7.61
Llyswen 0.59 0.61 0.62 0.64 0.65
Monmouth 1.00 1.03 1.05 1.07 1.09
Pilleth 0.76 0.77 0.77 0.78 0.78
Brecon/ Portis 1.60 1.67 1.74 1.80 1.84
Vowchurch 0.725 0.74 0.75 0.76 0.77
Whitbourne 1.251 1.24 1.23 1.22 1.22
SEWCUS 81.56 79.98 78.68 77.67 77.11
Tywi CU Area 41.07 40.87 40.72 40.62 40.61
Mid & South Ceredigion 4.84 4.71 4.60 4.51 4.46
North Ceredigion 2.28 2.38 2.47 2.55 2.61
Pembrokeshire 10.36 10.28 10.21 10.17 10.14
Table 4.3 - ELL targets by WRZ for AMP 5
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Current Leakage Policy
Our current baseline leakage policy complies with industry best practice. It follows the approach to
leakage optimisation outlined by the Department for Environment, Food and Rural Affairs, Ofwat and
the Environment Agency in 2002,31
supplemented by various reports published by Ofwat as part of
detailed reviews of certain aspects of the optimisation methodology (Ofwat, 2007) as well as its work
on “sustainable” Economic Level of Leakage, as referred to above.
The Tripartite study identified two principal methods of modelling leakage management costs:
the “BABE” approach (based on the use of a theoretical model identifying optimal intervention
frequencies); and
the “MELT” approach, which uses empirical information on leakage savings and costs to
determine directly both the natural rate of rise in leakage32 and the marginal costs of leakage
control.
Both methods are considered valid and during 2007 we switched from the use of the BABE
methodology to the MELT approach, using our Sustainable Achievable Leakage Targets model. The
methodologies embedded within Sustainable Achievable Leakage Targets are in line with industry
best practice. Full details can be found in the supporting report.33
District Meter Area coverage
Our current leakage strategy is implemented across the whole of our distribution network, which is
divided into 916 District Meter Areas. The flows into and out of the District Meter Areas are
permanently monitored, recorded and quality-controlled. In addition, service reservoir seepage and
trunk main losses are monitored, reported and quality-controlled at the WRZ level.
Information systems and databases
The flows into and out of all our District Meter Areas are permanently monitored and recorded, with
raw data transferred on a daily basis to our database system, LIBRA (Leakage Identification,
Balancing, Reporting and Abstraction). The data is then transferred into our bespoke Leakage
Monitoring and Reporting Software. This software is used for quality control, targeting/ranking and
reporting leakage. The system produces reports on a monthly basis, at District Meter Area,
operational area, WRZ and company level.
In addition to flow data, the information contained in daily “activity sheets” and DMA information packs
are now entered into our bespoke Leakage Monitoring and Reporting Software, enabling zone
specific leakage/ cost assessments and benchmarking of efficiency and costs to be carried out.
Pressure Management
31 “Best Practice Principles in the Economic Level of Leakage Calculation”: report commissioned by the Tripartite Group
consisting of Defra, the Environment Agency, and Ofwat. 32 The natural rate of rise (NRR) in leakage may be thought of as the continuing increase in leakage that would occur in the
absence of any leak repairs. It is made up of two components – the breakout of new leaks in the network plus the growth (increase in volume) of existing leaks. Of this total NRR, a proportion will comprise visible (customer-reported) leaks, which will be duly repaired. 33 “Determining the Short Run Economic Level of Leakage for AMP 5”: RPS, 2008.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Background leakage levels can be controlled by managing the pressure in the network. We have
undertaken considerable pressure management activity in recent years, and continue to sustain
savings by maintaining the status quo in areas where pressure is well-managed while working to
identify circumstances where further pressure management opportunities may exist.
New Property Forecasts
Property numbers within our area are projected to grow by an average of 0.65% per year over the
planning period. As a consequence there will be an expansion of the distribution network, which will
mean a corresponding increase in leakage.
Baseline Leakage
The initial Short Run Economic Level of Leakage value we derived from the optimisation process was
184.89 Ml/d. Analysis of zonal level values indicated lower levels, relative to current leakage, in 12 of
the 24 WRZs. We then used these preliminary values in our demand forecast and thereby identified
which WRZs were expected to go into deficit during the plan period.
It is inevitable that the revised leakage targets for 2014-15 will involve higher leakage levels in some
WRZs and lower levels in others, relative to the current position. However, in line with recent
regulatory guidance, for the two deficit WRZs where Sustainable Achievable Leakage Targets
indicated that rising leakage profiles would be appropriate, the Short Run Economic Level of Leakage
values have been constrained at the current zonal levels of leakage (in l/prop/d).
These constraints result in a reduction in the company level value by 0.81 Ml/d, producing a final
Short Run Economic Level of Leakage for 2014-15 of 184.08 Ml/d (including trunk mains and service
reservoir leakage). This value is 1.9 Ml/d higher than the figure calculated for the 2008 Draft Plan
(182.2 Ml/d).34
Future planned leakage reductions
Enhanced leakage reduction is a critical component of our Plan to maintain the supply demand
balance and reduce our CO2 emissions. For deficit WRZs, Sustainable Achievable Leakage Targets
was not used to determine the cost of leakage intervention schemes. This is because Sustainable
Achievable Leakage Targets utilises the current leakage policy costs that are consistent with short run
Economic Level of Leakage and not the costs of adopting more intensive leakage control
technologies that might be cost effective in contributing to deficit reductions.
An alternative methodology was used to derive the private and external costs of three alternative and
successively more intensive leakage control policies. These policies are:
reductions in detected leak run times – this option essentially increases the amount of
leakage detection resource made available;
location, operating and sounding of all fittings - this option targets previously undetected
leakage from all fittings, not just those that are visible without excavation; and
34
Note: out-turn leakage in 2010-11 was 199 Ml/d, higher than our leakage target of 190 Ml/d. This was the result of
exceptional weather conditions, notably the extreme “freeze-thaw” period in December 2010, and is expected to be recovered well in time for our end-AMP5 target of 184 Ml/d in 2014/15.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
installation of permanent correlator noise loggers – this option helps leakage teams
detect leaks quicker and to identify leaks that are not usually detected through conventional
means.
Details on how we assessed whether or not these policies were the best way to address supply
demand deficits are contained in Chapter 9.
4.7.5 Metering
As noted above in section 4.1, we estimate that the average per capita consumption for metered
households in the base year was 124 l/h/d compared with 160 l/h/d for non-metered households.
At present around 31% of our households are metered. Our demand forecasts assume that this
proportion will continue to rise in line with current trends, which would increase meter penetration to
70% by 2035. This is a significant continuing rate of uptake and we will monitor it closely through
annual reviews and our water resource planning process. During our current investment programme
(2010-15) we will be spending around £30 Million on metering (about 50% on installing meters for
new meter optants and 50% on maintenance of the total meter stock – currently around 370,000
household meters).
We have considered the policy option of “metering upon change of occupancy” as a potential means
to address supply demand deficits but this is not demonstrated to be cost-effective when compared
against other options.
4.7.6 Tariffs
Although we believe that some households reduce their consumption at the point when they switch
from the unmeasured to a measured tariff, the evidence suggests that on average measured
household demand in Wales is fairly unresponsive to changes in marginal price signals once a
customer is metered. Several years of optant demand data has shown us that post-switching optant
demand moves in line with other customer demand. In other words, demand appears to be fairly
price inelastic, once a customer is metered. Accordingly, we concentrate our demand management
efforts on seeking to influence behaviours through our water efficiency promotion activities, and at
present we do not regard alternative measured tariff structures as a potent tool to achieve supply
demand objectives. We continue to review evidence as it emerges, however, and retain an open mind
towards the possibility of applying different tariff structures in the future. Meanwhile, to maintain a
strong price signal we continue to ensure the volumetric rate for our metered tariffs is greater than our
actual variable costs.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Chapter 5. Target Headroom
“Headroom” is the difference between supply and demand: “Target Headroom” is one of the most
important features of water resource planning and is defined as the minimum planning margin or
buffer that a water company should allow between supply and demand to cater for specified
uncertainties35
in the overall supply demand balance (UKWIR, 2002).
These uncertainties include political, social, environmental and technical factors outside of a water
company‟s control that could significantly influence components of the supply demand balance.
Examples include changes to legislation, revisions to government political priorities, promotion of
economic development in specific areas, changes in planning methodologies, and so forth.
5.1 Calculating Target Headroom
We have assessed Target Headroom in accordance with the approach recommended by the
Environment Agency Guideline, as set out in “A Re-Evaluation of the Methodology for Assessing
Headroom” (UKWIR, 2002). Target Headroom is calculated by looking at the probability of uncertain
events in a similar way to the analysis of allowances for Outage. While the evaluation of Outage
entails examination of potential disruptions of short duration, the assessment of Target Headroom
involves consideration of events and uncertainties of potentially longer duration.
In line wiith the UKWIR methodology, Target Headroom is analysed in terms of nine supply
components and four demand components, viz:
S1 Vulnerable surface water licences
S2 Vulnerable groundwater licences
S3 Time-limited licences
S4 Bulk imports
S5 Gradual pollution causing a reduction in abstraction
S6 Accuracy of supply-side data
S8 Uncertainty of impact of climate change on source yield
S9 Uncertain output from new resource developments
D1 Accuracy of sub-component data
D2 Demand forecast variation
D3 Uncertainty of impact of climate change on demand
D4 Uncertain outcome from demand management measures
35
Except for those relating to Outages, which are treated as part of Deployable Output, as set out in chapter 3 above.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Of the above categories, the uncertainty surrounding the effects of climate change on supply/demand
forecasting is especially significant in the preparation of this Plan, and is analysed in detail in Chapter
7 below.
5.2 Risk Profile
The Environment Agency Guideline recommends that an appropriate risk profile is applied to the
assessment of Target Headroom, and we have carefully considered how we should approach this for
the purposes of planning. On the one hand it would not be appropriate to allow for all possible
uncertainties in Target Headroom, because this would be overly cautious (and very expensive). On
the other hand, it could be argued that it would not be correct to look only at the probability-weighted
expected value of the uncertainties, i.e the “50 percentile” or “central projection”, because there is an
asymmetry between the value of having too much water and too little water. We have therefore
examined uncertainty from more than one perspective on risk. Further details are set out in chapter
7. After due consideration and analysis, we have chosen to adopt a fixed Risk Profile across the
planning period at the 95% confidence level.
Target Headroom has been calculated for all 24 WRZs at zonal level36
for both the Annual Average
and the Critical Period scenarios.
5.3 Baseline and Final Planning
The calculation of Target Headroom is part of the process of iteration that characterises the planning
process. Initially, “Baseline” Target Headroom Is calculated for each WRZ and applied to the
derivation of the baseline supply demand balance. If a WRZ is identified as having a supply deficit
options are selected to resolve the deficit. Since implementation of these solutions will also bring
uncertainties Target Headroom is then re-calculated and the process repeated until supply demand
balance is achieved. Thus, “Final Planning” Target Headroom is included as part of the Final
Planning supply demand balance, in which the supply deficit is fully resolved.
5.4 Work carried out since the 2008 Draft Plan
Following the 2008 Draft Plan, in preparation for the submission to Ofwat of Welsh Water‟s Final
Business Plan for 2010-2015, we undertook a detailed review of our headroom assessments. The
main areas of this work were:
a full review of the headroom allowances used in the Tywyn Aberdyfi WRZ;
a complete review of climate change uncertainty, including a full audit of our work and the
results of our analysis, a comparison of different methodologies for taking climate change into
account including an assessment of all of the approaches put forward by the Environment
Agency (see chapter 7 below);
a review of inflow uncertainty. This has resulted in a change in one zone, Tywyn Aberdyfi,
where we had allowed for uncertainty of inflows on both the Afon Fathew and the Nant Braich
36
Headroom Analysis (Entec, 2010); 2010 Review of Consents Assessment in SEWCUS Water Resources Zone, Final Report
(Entec, March 2011); 2010 Review of Consents Assessment in Pembrokeshire Water Resources Zone, Final Report (Entec, January 2011); Revised Target Headroom Modelling for NEYM (Entec, December 2010); Revised Target Headroom Modelling for Brecon – Portis Water Resources Zone (Entec, March 2011), NEYM DO summary (Welsh Water, 2010).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
y Rhiw, whereas in fact they operate under an aggregated licence which means that if inflows
are lower in one, abstraction from the other can be increased.;
a complete re-assessment of the headroom uncertainty on demand; and
Final Planning Target Headroom was derived through a process of iteration for the three
zones presented as being in deficit in the Final Business Plan – Tywyn Aberdyfi, South
Meirionnydd and Vowchurch.
Full details of this work can be found in the associated report.37
For this Plan, baseline Target Headroom has been updated for all WRZs to account for the updated
demand forecast and the inclusion of the impacts of the UK climate change forecasts published in
2009 (UKCP09) and the outcomes of the Environment Agency‟s review of our licences. Full details
are set out in the associated reports.38
37 “Further Headroom Analysis – Summary of Headroom Components post dWRMP”: Entec 2008.
38 “2010 Review of Consent Supply Assessments in SEWCUS Water Resources Zone, Final Report” Entec, Jan 2011. “2010
Review of Consent Supply Assessments in Pembrokeshire Water Resources Zone, Final Report”: Entec, Jan 2011. Headroom Analysis (Entec, 2010); 2010 Review of Consents Assessment in SEWCUS Water Resources Zone, Final Report (Entec, March 2011); 2010 Review of Consents Assessment in Pembrokeshire Water Resources Zone, Final Report (Entec, January 2011); Revised Target Headroom Modelling for NEYM (Entec, December 2010); Revised Target Headroom Modelling for Brecon – Portis Water Resources Zone (Entec, March 2011), NEYM DO summary (Welsh Water, 2010).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Chapter 6. The Habitats Directive and the Impact on Water Abstractions
The European Habitats Directive will have a significant influence on our water resource management
plans for the next 25 years. This chapter describes the Directive, how it operates through the Review
of Consents process, and the practical implications that this has for our long term strategy for meeting
our water supply obligations.
6.1 The Habitats Directive
The Directive was brought into Welsh law through regulations39
that
provide for the designation of “European sites” (Natura 2000 sites);
afford protection of “European protected species”;
provide for the adaptation of planning and other controls for the protection of such sites; and
impose a statutory requirement to deliver improvement schemes.
Under the Regulations, “competent authorities” i.e. any Minister, government department, statutory
authority, public body, or person holding public office, have a general duty, in the exercise of any of
their functions, to have regard to the EU Habitats Directive.
As the designated “competent authority” for England and Wales the Environment Agency is required
to ensure that its “permissions” – i.e abstraction licences and discharge consents – and its operations
have no adverse effect on the “integrity” of the Special Areas of Conservation (SAC) and Special
Protection Areas (SPA) that form part of the pan-European network of Natura 2000 sites. As a
competent authority ourselves, we must have regard to the requirements of the Habitats Directive so
far as they may be affected by the exercise of our functions..
6.2 Review of Consents (and Restoring Sustainable Abstraction programme)
The Review of Consents process is the mechanism by which the Environment Agency reviews of all
the existing and proposed permissions it has issued that could impact upon EU designated Natura
2000 sites. The process falls under the umbrella of the Environment Agency‟s Restoring Sustainable
Abstraction programme. This programme was set up by the Environment Agency in 1999 to identify
sites that may be adversely impacted by the effects of abstraction, and is ongoing. It has proved
complex in Wales because of the nature of the environment in which we operate; there are, for
example, over 90 European Special Areas of Conservation and more than 1,000 Sites of Special
Scientific Interest (SSSI).
Sustainability reductions is the term given to amendments made by the Environment Agency to
existing permissions in order that it can be demonstrated that the permission does not have an
adverse impact on a Habitats Directive site.
39 The EEC Directive 92/43/EEC (21st May 1992) on the conservation of natural habitats, wild fauna and flora was incorporated
into the UK regulatory system under the Conservation (Natural Habitats, &c.) Regulations 1994. These regulations came into
force on 30 October 1994 and were subsequently amended in 1997 and (in England only) 2000. They have since been
amended by the Habitats Regulations 2010.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
The abstractions affected are shown on Figures 6.1, 6.2 and 6.3: further detail is presented in Annex
3.
Figure 6.1 - Welsh Water’s abstractions in South East Wales subject to the review of consents
process
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Figure 6.2 - Welsh Water’s abstractions in South West Wales subject to the review of consents process
Figure 6.3 - Welsh Water’s abstractions in North Wales subject to the review of consents process
In general terms Habitats Regulations oblige the Environment Agency to review all of its
environmental permissions, in this case abstraction licences, to ensure that they have no adverse
impact on Special Areas of Conservation. The process is undertaken in four stages:
Stage Assessment
1 This stage identifies all relevant (Environment Agency) permissions that could impact upon
the Special Area of Conservation
2
Permissions are then subject to a generic assessment to determine if a likely significant
impact exists upon the integrity of the designated site, either alone or in combination with
other permissions. If deemed likely, or the Environment Agency are unsure, they move on
to Stage 3.
3
A more detailed assessment of each permission is carried forward from Stage 2 to
determine whether it can be shown to have no adverse effect upon the integrity of the site
in question, either on its own or in combination with other permissions.
4
If at Stage 3 a permission has been assessed as having no adverse affect then it will be
affirmed at Stage 4 and no modifications to it will be required. If, however, a conclusion of
no adverse affect could not be reached, then the permission will be subject to “options
appraisal” to determine the best way to resolve the issues.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
The consents review process for water resources has been ongoing in Wales since 2004. During this
period we have worked closely with the Environment Agency to try and understand the issues at each
site and how they can best be resolved. Stages 3 and 4, as they relate to our abstractions, are
described in greater detail below.
6.2.1 Stage 3
The assessment has been based upon the Resource Assessment Methodology used in the
Environment Agency‟s Catchment Abstraction Management Strategy process. Under this
methodology a generic environmental river flow objective is applied at key sites along the river that
allows for small deviations from the estimated natural flow, taking into account the effects of all the
permissions.
For the rivers under investigation that have been designated as Special Areas of Conservation under
the Habitats Directive, flows are generally only allowed to deviate below natural flows by a maximum
of 10% from Q1 to Q9540
and only 5% thereafter. This process is referred to in the methodology as
the Habitats Directive Environmental River Flow objective.41
This means, for example, that if the
natural flow at Q95 is 10 Ml/d the permitted deviation is only 5% of 10 Ml/d i.e. 0.5 Ml/d and so the
Environmental River Flow objective, i.e. the flow to be preserved at all times, would be 9.5 Ml/d.
Where more localised information on the flow requirements of designated species has been available,
for example on the River Usk Special Area of Conservation, the Habitats Directive Environmental
River Flow has been adjusted accordingly.
This process is illustrated in Figure 6.4, which shows that:
the Environment Agencydetermine the “Benchmark Flow” i.e. the natural flow of the river –
this is the red line on the diagram;
the Environment Agencyand the Countryside Council for Wales determine the Benchmark
Habitats Directive Ecological River Flow objective as the protective flow requirement for
Special Area of Conservation rivers – this is typically 10% below the benchmark flow – the
yellow line;
the Environment Agency then assesses the fully licensed scenario – licences operating at
100% - and this is shown as the dark blue line labelled “Max licensed scenario flows”; and
the dark blue line lies below the yellow line from about the 65%ile of river flow onwards
towards the lower flows. As a consequence, the abstractions from this point would have to be
reduced to move the dark blue line above the yellow line.
The Stage 3 appropriate assessments have focused on two licensing scenarios for each of the
Special Areas of Conservation – a “recent actual” scenario that reflects how we have actually been
operating our abstractions over the past 35 years (1970 – 2005) and a “full licence utilisation”
40 The term Q95 is often used to mean the 95 percentile flow statistic. This is the flow that is equalled or exceeded for 95% of
the time, based on the length of the record used to calculate the statistic. It is typically calculated from daily mean flow values. In hydrology/ water resources it is a well understood and used low flow measure as, on average, only 5% of flows are lower in value. Conversely, Q1 represents a high flow value as 99% of flows are lower in value, or alternatively, only 1% of flows are higher in value. 41 Habitats Directive Ecological River Flow Duration Curve (HD ERF) is the flow regime suggested for Special Areas of Conservation rivers based on the findings of an Environment Agency Research and Development Report “An Appraisal of the Value of the EW System for assessing impacts on HD Interest Features”.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
scenario which represents an extreme worst case scenario under which the maximum licensed
volumes are abstracted all year round.
Figure 6.4 Application of the Review of Consents process
Lake Special Areas of Conservation
As with the riverine Special Areas of Conservation, the Environment Agency has assessed our
operations in relation to Lake Special Areas of Conservation under both “maximum licensed” and
“recent actual” scenarios. The impact upon lake levels of our abstraction under these two scenarios
has been calculated, but unlike in the case of the riverine Special Areas of Conservation, no Habitats
Directive limit of deviation has been set. The assessment has instead focused on the extent to which
there is an increase in the marginal area exposed as a consequence of abstraction drawing down the
levels in the lake.
Where it has been shown that the drawdown rates cause a significant increase in the area of marginal
habitat exposed, which could negatively impact upon the designated species, the conclusion has
been drawn that “no adverse impact” cannot be demonstrated and so the relevant abstraction
licences have progressed to Stage 4.
There are some specific features of the Review of Consents process that are worth noting:
1. The Habitats Directive does not require it to be demonstrated that abstractions are actually
having a detrimental impact for a permission to be curtailed or modified. Rather, it requires a
demonstration that there is no impact for the permission to be unchanged. Thus, if “no
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
impact” cannot be proven, the “precautionary principle” applies,42
and the permission may be
modified.
2. The process focuses upon a hypothetical scenario where all abstraction licences are being
operated at their theoretical maximum, a position which has never been achieved in practice.
3. Review of Consents looks at risk of adverse impact, as well as actual impact.
Table 6.1 presents the results for 20 sites of the Environment Agency‟s Stage 3 assessments as to
whether there is either an actual (current) impact, or a perceived modelled (future) risk were we to
abstract at the maximum licensed rates. As noted above, the simulation of the “maximum abstraction”
scenario is entirely theoretical as we have never needed to abstract 100% of our daily licensed limit at
all the sites along these rivers, and it is very unlikely that we would ever need to in the future. This is
borne out by the results presented in the table, which shows that at all sites, the only impacts from our
abstractions are in the “modelled risk” category. In other words, under the recent actual scenarios no
perceived risk of adverse impact has been identified.
42
Under the precautionary principle, if there are reasonable grounds for suspecting that environmental harm may occur, protection measures should not be delayed pending scientific proof.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Site Name
Adverse
effect on
site integrity
can be
shown
No adverse
effect on
site integrity
cannot be
shown
Impact (I) or a Risk (R) if cannot conclude there is no impact
Impact type: Actual (A) Modelled (M) Or Suspected (S)
Alo
ne
In
Co
mb
inatio
n
Alo
ne
In
Co
mb
inatio
n
Wye at Broomy Hill R M
Wye at Monmouth (Mayhill) R M
Wye at Monmouth (Wye
Transfer) R M
Lugg at Byton R M
Pilleth boreholes R M
Dunfield boreholes R M
Midsummer Meadow well R M
Usk at Llantrisant R M
Usk at Rhadyr (Prioress Mill) R M
Usk at Brecon/Brecon
boreholes R M
Tywi at Manorafan R M
Tywi at Nantgaredig R M
Llyn Brianne reservoir R M
Teifi at Llechryd R M
Eastern Cleddau at Pont
Hywel R M
Eastern Cleddau at
Canaston R M
Western Cleddau at Crowhill R M
Llyn Eiddew Mawr R M
Llyn Morwynion R M
Llwyn Isaf borehole R M
Table 6.1 – Outcome of Stage 3 Assessments
6.2.2 Stage 4
At Stage 4 of the consents review process the Environment Agency then specifies a series of
“Environmental Outcomes” as illustrated in Table 6.2 below.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Environmental
Outcome Objective
Env1 To ensure adequate flow throughout the Special Area of Conservation
Env2 To ensure flow variability (which can be achieved, for example, by removing diurnal
pumping practices)
Env3 To ensure frequency and magnitude of spate flows. The Environment Agency has
assumed that if Env1 is achieved then by default so will Env3
Env4 To prevent entrainment and impingement
Table 6.2 – Specified Environmental Outcomes at Stage 4
There is also an assessment of other potential impacts, such as those that relate to entrainment,
temperature, fish passage, water level and variability of flow, some of which are described later in this section, which go together to produce an overall picture of the potential impacts of our activities upon the Special Areas of Conservation. The outcomes are shown in Table 6.3. In general terms, the major impact upon existing abstraction licences is a reduction in volumes that
can be abstracted during periods of low flow so as to retain a (theoretical) “naturalised flow” within the
river (Environmental Outcome 1).
The impact of Environmental Outcome 2 - The removal of diurnal pumping (taking water at night to
save on pumping costs) - has a small impact upon the volume of water we can take, but mostly
impacts on operating costs.
The prevention of entrainment and impingement has no direct impact on water resources, but does
impact upon the utility of our abstraction assets. This is described further below.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Licence Flow, Env 1 Variability, Env 2 Spate, Env 3 Entrainment, Env 4 Temperature Level Barrier
River Wye at Broomy Hill
River Wye at Monmouth (Wye Transfer)
River Wye at Monmouth (Mayhill)
River Wye at Builth Wells
River Wye at Llyswen
Vowchurch boreholes
Alton Court boreholes
Buckholt spring
Rogerstone Grange borehole
River Lugg at Byton
Pilleth Boreholes
Dunfield Boreholes
Midsummer Meadow
River Usk at Llantrisant
River Usk at Brecon
Brecon Boreholes
River Usk at Rhadyr (Prioress Mill)
River Lugg at Byton
Pilleth Boreholes
Eastern Cleddau at Pont Hywel
Western Cleddau at Crowhill
Eastern Cleddau at Canaston
Afon Teifi at Llechryd
Afon Tywi at Nantgaredig
Afon Tywi at Manorafon
Llyn Brianne
Llyn Cwellyn
Afon Gwyrfai at Nant Mills
Llyn Eiddew Mawr
Llyn Morwynion
Llwyn Isaf borehole
Table 6.3 – Environmental Outcomes
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
6.3 The impact of Review of Consents upon Resources
Following the completion of Stage 4 of the consents review process, we have modelled the
Environment Agency‟s proposed licence amendments to assess the impacts upon Deployable Output.
Overall, the reductions amount to an approximate Deployable Output loss of 116 Ml/d across South
Wales. However, by changing the way we operate our licences in the Pembrokeshire WRZ this
impact is reduced to 92 Ml/d. Across North Wales we are not forecasting any loss of Deployable
Output in the affected WRZs as a result of the Environment Agency‟s proposed licence changes.
6.3.1 The South East Wales Conjunctive Use System (SEWCUS) WRZ
Since 2007, we have worked with the Environment Agency to develop a series of licence amendment
options for the Rivers Wye and Usk to achieve the desired environmental outcomes. This Plan is
based on the latest options set out in the technical notes issued by the Environment Agency in
September 2010 – Wye Option W38243
and Usk Option U588.44
We have prepared a report45
that provides full details of the modelling work we have carried out to
assess the impacts upon Deployable Output of the final outcomes of the Agency‟s review of our
related consents.
Within the SEWCUS WRZ, the baseline Dry Year Deployable Output is 476 Ml/d. Implementation of
the licence amendments reduces our Dry Year Deployable Output to 401 Ml/d, a loss of 75 Ml/d. This
drop in supply capacity is driven by the significant reductions in our Wye and Usk licences, as well as
the increase in releases we have to make from the Elan Valley reservoirs to augment flows in the
Wye so as to enable abstraction at Monmouth to be maintained. As a consequence of these
changes, our overall supply/demand position in SEWCUS is projected to move from a healthy excess
of supply capacity over demand to a much smaller surplus.
Further, it should be noted that we have assumed, for the purposes of this Plan, that the licence
amendments are not formally put in place until 2020, although in fact the sustainability reductions
would not put the zone into deficit straight away, but leave a small planning surplus for the time being
according to current modelling. The size of the reductions is so dramatic that we consider that it
would be prudent to carry out further detailed work on the way that the zone is operated in order to
ensure that it is fully robust to such radical changes. Our over-riding priority is to safeguard the
security of public water supplies, and the complexity of the zone is such that more extensive analysis
is required before we can be fully confident that the major changes envisaged can be accommodated
in all circumstances. In particular, whilst SEWCUS is regarded as one zone for planning purposes, it
is not fully integrated in the sense that not every customer can theoretically be served by each source.
As such, the presence of effective bottlenecks raise the question of whether it should be modelled as
two (or more) inter-connected zones, rather than one. We intend to explore this issue carefully, and if
there is a valid alternative way of analysing the zone we will wish to ensure that what appears to be a
small planning surplus overall does not conceal the fact that there would be local areas that would be
in deficit.
6.3.2 Brecon-Portis WRZ
The impact of the consent review process on Deployable Output in our Brecon-Portis WRZ has been
calculated as a reduction of approximately 2.5 Ml/d.
43
Technical Note: Wye Option W382, EAW, September 2010.
44 Technical Note: Usk Option U588 & U591b, EAW, November 2010.
45 “2010 Review of Consent Supply Assessments in SEWCUS Water Resources Zone, Final Report” Entec, Jan 2011.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
6.3.3 Pembrokeshire WRZ
Since 2008 we have undertaken modelling of our Pembrokeshire WRZ to understand fully the impacts
of the Environment Agency modifications to our abstraction licences on the Eastern and Western
Cleddau Rivers. The Environment Agency has not modelled the impacts themselves but have fully
audited our model and have indicated that they are satisfied with the results.
The current baseline Dry Year Deployable Output for Pembrokeshire is 79.10 Ml/d and 100.50 Ml/d
for the Critical Period. We have prepared a report46
that details our modelling work and the impact of
the consent review process on Deployable Output in Pembrokeshire.
The impact of the Environment Agency‟s proposed changes to licences in Pembrokeshire is a net
reduction in annual average Deployable Output from 79.1 Ml/d to 64.8 Ml/d and in critical period
Deployable Output from 100.5 Ml/d to 81.9 Ml/d. Note that these results are after we have mitigated
the effect of the impacts of the consent review by changing the way we operate the zone: these
changes, which are described in the supporting report, have not hitherto been implemented because,
but for the effects of the consent review process, it would not have made economic sense to do so.
The consequence of the proposed licence amendments at our Pont Hywel intake on the Eastern
Cleddau is that our abstraction would be restricted to less than 1 Ml/d, on average, during the summer
months, compared with the present situation in which we can abstract an average of 10 Ml/d. This
means that Preseli reservoir storage could not be sustained through the summer, which in turn means
that Preseli Water Treatment Works could not be operated at normal levels throughout the summer,
and so the Deployable Output of the Pembrokeshire WRZ would be greatly reduced, albeit that this
would then be partially mitigated by greater use of the Llysyfran to Preseli Water Treatment Works
transfer.
Note that, as for the South East Wales Conjunctive Use System zone, we have assumed that the
proposed abstraction licence reductions are not implemented before 2020. This is because of the
considerable lead time necessary to implement the solutions (see chapter 9 below).
46 “2010 Review of Consent Supply Assessments in Pembrokeshire Water Resources Zone, Final Report”: Entec, Jan 2011.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Chapter 7. Uncertainty Regarding the Effects of Climate Change
Climate change is expected to have a significant impact on both water supply and demand in the
future. Our plan incorporates the latest climate scenarios, UK Climate Projections 2009 (UKCP09),47
and looks at the potential impact of these scenarios on supply and demand. Overall we are projecting
a reduction in Deployable Output in a number of WRZs as a consequence of climate change,
increasing the likelihood of water supply deficits. We also show the dramatic effect that the
incorporation of the full range of UKCP09 projections into Target Headroom has in certain zones.
7.1 How we approach climate change
In June 2009 the United Kingdom Climate Impacts Programme (“UKCIP”) published new climate
change scenarios, known as “UKCP09”, which replaced the UKCIP‟s 2002 projections that we had
used in our 2008 plan.
It is generally accepted that there are major uncertainties in the modelling of climate change,
particularly as regards:
the severity of the changes we might see;
the timescale for changes; and
the probability of any particular scenario occurring.
For the purposes of preparing this Plan, we have used the “medium” climate change scenarios rather
than either the upper or lower scenarios.
Compared with the UKCIP 2002 projections, the main differences that these new scenarios bring to
the planning process are:
1. the variability in seasonal changes in rainfall is much greater than previously projected; and
2. this is particularly pronounced for summer rainfall, which can vary from +20% to -40%. Most
importantly, the probability of both drier winters and wetter winters is considered to be greater,
which may significantly affect water resources.
When we analyse the effects of climate change we make an assessment of the effects on the
availability of water. We have not considered any potential changes to our licences that could be
made in response to climate change.
The treatment of uncertainty involves rigorous analysis and careful judgement. Figure 7.1 shows how
the probability distribution around the effects of Target Headroom on water availability “fans out” as
we move progressively into the future. (The overwhelming bulk of this uncertainty is related to the
effects of climate change, the so-called “S8” component of Target Headroom, with only some 10%
being driven by other components.) This means that the implications for supply demand deficits and
the range of investment and other options that might have to be considered varies enormously
depending on how much risk the company is willing to bear. For example, in the case depicted in
Figure 7.1, which relates to our largest zone, the South East Wales Conjunctive Use System zone
(SEWCUS), if the company is willing to accept a 50% risk that the allowance in Target Headroom will
be inadequate by 2034 (e.g. on the basis that it considers that there is adequate lead time to deal with
shortfalls as at that date as better and less uncertain information becomes available) it would build 44
Ml/d into Target Headroom in this zone. If, on the other hand, it took a more cautious approach and
47 “UK Climate Change Impacts Programme (UKCIP)”: Murphy et al 2009.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
wanted to be 95% sure that sufficient margin had been built into Target Headroom to allow for the
effects of climate change by 2034, it would allow 130 Ml/d, a very dramatic difference.
Figure 7.1 – Target Headroom for SEWCUS at different levels of risk
As described below, having analysed the implications of the UKCP09 climate scenarios in detail, we have treated the uncertainty around them as follows:
we have reflected the UKCP09 50 percentile impacts in our projections of Deployable Output,
as appropriate. This is in line with Environment Agency Guidelines; and
we have quantified the additional effect of the full range of UKCP09 climatic impacts in our
evaluation of Target Headroom, but have not used these sensitivities for the purposes of the
main supply demand assessment and option appraisal in chapters 8 and 9. We have,
however, presented what the outcomes would be if we had used the full range of UKCP09
impact (see below for further discussion).
It is worth noting, in this context, that the choices we have considered revolve around the “central” or
“neutral” projections (50 percentile) and the “cautious” or “pessimistic” scenarios (95 percentile). We
are not concerned with the 5 or 10 percentile projections, which could be termed “optimistic” and
indeed which, as figure 7.1 illustrates, actually imply negative target headroom.
7.2 The impact on supply
Following the publication of UKCP09 climate change scenarios we analysed its impact upon
Deployable Output in 17 of our 24 WRZs.48
The impacts on the North Eyri Ynys Mon, SEWCUS and
Pembrokeshire WRZs were assessed further as part of the work we carried out on these zones
following changes to the baseline models in 2010. The impacts are summarised in Table 7.1 below.
48
“N177i4 Assessment of the Impact of Climate Change on Deployable Output using UKCP09 Scenarios”: Entec March 2010.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
The impact of climate change in the remaining 7 WRZs under the UKCP09 scenarios remains the
same as under the UKWIR06 approach.49
This assumes that water availability is essentially
unaffected because the relevant constraints on Deployable Output are the abstraction licence
conditions. Currently, therefore, the effect of climate change is considered to be zero.
49
As presented in “Effects of Climate Change on River Flows and Groundwater Recharge: Guidelines for Resource Assessment and UKWIR06 scenarios” (UKWIR 2007).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Zone Median (50%ile)
impact on DO from UKCP09 in 2035
Zone Median (50%ile)
impact on DO from UKCP09 in 2035
North Eyri Ynys Mon -18% Hereford 0%
Clwyd Coastal -1% Llyswen 0%
Alwen Dee 0% Monmouth 0%
Bala 0% Pilleth 0%
Tywyn Aberdyfi -1% Brecon Portis 0%
Blaenau Ffestiniog -3% Vowchurch -3%
Barmouth -1% Whitbourne -2%
Lleyn Harlech -1% SEWCUS 0%
Dyffryn Conwy 0% Tywi Gower 0%
South Meirionydd 0% Mid & South Ceredigion50 +3%
Ross On Wye 0% North Ceredigion -6%
Elan Builth 0% Pembrokeshire -16%
Table 7.1 Summary of median impact of UKCP09 climate change scenarios on baseline Deployable Output
The zone where UKCP09 has the biggest negative impact on Deployable Output is North Eyri Ynys
Mon with an 18% reduction in Annual Average Deployable Output, followed by Pembrokeshire with
16%. The impact on the other zones is less than 10%, including 4 zones where climate change is
expected to have no effect, either because Deployable Output is already constrained by licence
conditions or because it is bounded by the availability of storage.
The impact of the scenarios is generally greatest in west Wales, particularly in those zones that rely
on river abstractions where licence conditions may limit what we can abstract at times of low river
flows. This explains, for example, the magnitude of the impacts in Pembrokeshire and Tywyn
Aberdyfi.
7.3 The Impact on Target Headroom - Supply
Although the Environment Agency‟s Water Resources Planning Guideline requires companies to build
the effects of UKCP09 climate change projections into their water resources planning, there is
currently no guidance as to precisely how this should be done. Further, in its latest (April 2011)
update of the Guideline the Environment Agency acknowledges the uncertainty around the question
of how UKCP09 scenarios should be applied to produce robust figures for the “S8” component of
Target Headroom.51
We have therefore used our judgement in deciding how our forecasts and
assumptions should be modified to reflect the UKCP09 scenarios, drawing extensively on the
principles contained in relevant UK Water Industry Research, where appropriate.
50
For this zone, the median UKCP09 scenario has a slight positive impact on DO.
51 In section 8.4 the Guideline states: “We are currently working with the water industry to research suitable methodologies to
enable these new scenarios to be used for water resources management plan assessments. Once these methodologies have been developed we will issue updated guidelines on climate change assessment for water resource planning.”
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
We have examined how the incorporation of the full UKCP09 range of climatic scenarios into Target
Headroom would affect the supply demand position in each zone. The following presents the net
position in 2035 for each of our 24 zones:
on a “preliminary” view, before the effects of the Environment Agency‟s consent review
process and climate change are taken into account;
after allowance is made for the impact of the Environment Agency‟s consent review process,
as described in chapter 6;
incorporating both the effects of the Environment Agency‟s consent review and the 50
percentile (median) UKCP09 scenarios in Deployable Output; and
after allowing both the Environment Agency‟s consent review and the more cautious full range
of UKCP09 scenarios (5 percentile to 95 percentile) projections on Deployable Output and
Target Headroom.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Supply Demand Position in 2035 (Ml/d)
Baseline
(wholly
excluding the
effects of the
Environment
Agency’s
consent
review and
UKCP09)
Including the
Environment
Agency’s
consent
review
Including the
Environment
Agency’s
consent
review and
the effects of
the median
UKCP09
scenario on
Deployable
Output
Including the
Environment
Agency’s
consent
review and
the full range
of UKCP09 in
Target
Headroom
8001, North Eyri Ynys Mon +11.3 +11.3 +2.9 -4.3
8012, Clwyd Coastal +2.5 +2.5 +2.2 +1.7
8014, Alwen – Dee +7.8 +7.8 +7.8 +7.5
8020, Bala +0.1 +0.1 +0.1 +0.1
8021, Tywyn – Aberdyfi +0.1 +0.1 +0.1 +0.1
8026, Blaenau Ffestiniog +0.5 +0.5 +0.5 +0.4
8033, Barmouth 0 0 0 0
8034, Lleyn – Harlech +5.0 +5.0 +5.0 +4.8
8035, Dyffryn – Conwy +3.4 +3.4 +3.4 +3.4
8036, South Meirionnydd 0 0 0 0
8101, Ross on Wye +1.7 +1.7 +1.7 +1.7
8102, Elan – Builth +2.6 +2.6 +2.6 +2.6
8103, Hereford Conjunctive
Use System
+11.5 +11.5 +11.5 +11.5
8105, Llyswen +1.3 +1.3 +1.3 +1.3
8106, Monmouth +1.7 +1.7 +1.7 +1.7
8107, Pilleth +0.9 +0.9 +0.9 +0.9
8108, Brecon – Portis +1.9 -0.7 -0.7 -0.7
8110, Vowchurch +0.9 +0.9 +0.8 +0.8
8111, Whitbourne +1.6 +1.6 +1.5 +1.5
8121, SEWCUS +74.6 -2.7 -12.4 -104.2
8201, Tywi Conjunctive Use
System
+22.1 +22.1 +22.1 +22.1
8202, Mid & South Ceredigion +4.1 +4.1 +4.8 +4.4
8203, North Ceredigion +0.9 +0.9 +0.3 +0.0
8206, Pembrokeshire +5.2 -8.3 -12.7 -18.2
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Table 7.2 – Effect of the Environment Agency’s Review of Consents (RoC) and Climate Change on Supply Demand Deficits in 2035
The following chart illustrates how the position changes for each of the four sets of projections for the
the South East Wales Conjunctive Use System (SEWCUS) zone, where the full range of UKCP09
scenarios has the greatest impact.
Figure 7.2 – Illustration of the effect of UKCP09 climate predictions on the supply demand
balance - SEWCUS
As the chart shows, before the effects of the Agency‟s Review of Consents and UKCP09 are taken
into account, SEWCUS is projected to remain in healthy surplus throughout the Plan period. The
effect of Review of Consents, by itself, is to wipe out the 75 Ml/d surplus shown in the top line for
2034, and to produce a small overall deficit of -3 Ml/d. The incorporation of the median UKCP09
scenario into Deployable Output moves the zone further into deficit, with the 2034 position
deteriorating to a shortfall of 12 Ml/d.
When the full UKCP09 scenarios relating to the impacts of climate change are incorporated in Target
Headroom, however, a massive 104 Ml/d deficit is reached by the end of the Plan period. To put this
further into context, the following table shows how this deficit is made up.
-150
-100
-50
0
50
100
150
2009 2014 2019 2024 2029 2034
Ml/
d
Supply Demand Balance SEWCUS
Baseline (wholly excluding impacts of climate change)RoC (wholly excluding impacts of climate change)RoC (only UKCP09 50%ile directly on Deployable Output)RoC (full range of UKCP09 accounted for within Target Headroom also)
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
SEWCUS in 2034 (Ml/d)
Water available for use 378
Demand 363
Target Headroom 119
Supply demand balance -104
Table 7.3 Primary components of supply demand balance in 2034 - SEWCUS
For the purposes of this Plan we gave careful consideration to whether we should base our strategy
for planning investment and other options for achieving supply demand balance on the basis of
projections that included or excluded the “S8” component of Target Headroom. On the one hand, we
acknowledge that climate change is a major source of uncertainty, especially in relation to its
interaction with the effects of the Agency‟s consents review. On the other hand, we note that this is a
developing area, and that best practice is not yet established: as noted above, the Environment
Agency has acknowledged that there is some uncertainty as to how UKCP09 should be reflected in
methodologies for determining Target Headroom, and plans to issue guidance in time for the 2013
draft WRMPs. There is also a question mark over how relevant an exercise it would be at this stage
to prepare options for meeting a projected 104 Ml/d deficit in SEWCUS, an addition to capacity that is
greater than the total water supplied by some other water undertakers.
On balance, we have taken the pragmatic decision to opt for the latter approach. We consider that
the uncertainty around how the full UKCP09 climatic scenarios should best be incorporated in water
resource management planning, and Target Headroom in particular, is too wide to be relied upon at
the present time for reliable projections of future water resource needs. We are confident that there is
adequate lead time between now and the point at which we would have to commit to a programme of
investment to address a deficit of the magnitude presented in Table 7.3, and will be in a position to
take a more positive and less speculative view when we prepare the next draft Water Resources
Management Plan, due for publication in 2013.
In effect, therefore, for the purposes of the supply demand balances shown in the following section
and the options for addressing supply demand deficits presented in chapter 9, we have incorporated
the median UKCP09 scenarios in our projections of Deployable Output, but have not included an
allowance for the uncertainty around the projections in our calculations of Target Headroom. It should
be noted, however, that we have presented for information the options that we would select if we had
included that allowance, i.e. addressed the full deficits shown in the final column in Table 7.2 above
(see section 9.7 for details).
7.4 The Impact on Target Headroom – Demand
We have, though, included the effect of climate change on demand in Target Headroom. Many of the
components of the demand for water are influenced by weather conditions. For example, garden
watering increases significantly in hot and dry weather. Research by Oxford University for the
Department for Environment, Food and Rural Affairs52
provides the best available estimates of the
impact of climate change on future demands for water, as reflected in the UKCIP02 scenarios. The
study presented indicative predictions, for a variety of scenarios, of the potential impact of climate
change on key components of household and non-household water demands, based upon historical
52 “CCDeW: Climate Change and the Demand for Water”: Defra, 2003.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
analysis of trends. Although we would welcome an industry update to this study to account for the
changes in climate change projections, we consider that it provides a reasonable basis for the
estimation of the effects of climate change on demand for the purposes of this Plan, and have
reflected it in our forecasts of the supply demand balance for each zone, as presented in the following
Chapter.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Chapter 8. The Supply Demand balance
This purpose of this chapter is to present the supply demand position for Wales over the Plan period.
We do so on the basis of the (“central”) approach we have taken to climate change uncertainty, as
described in chapter 7, and also present equivalent results on the basis of the incorporation of the
(more “cautious” or “pessimistic”) full range of UKCP09 scenarios in the “S8” component of Target
Headroom. We have not prepared projections on the basis of an “optimistic” view of the effect of
climate change on Target Headroom.
8.1 Calculating the Supply Demand Balance
The basic question in water resources planning is whether or not the supply of water, or “Water
Available for Use”, is expected to be sufficient to meet the demand for water (defined as Demand plus
Target Headroom), and therefore whether a zone is expected to be in surplus or in deficit (see figure
8.1).
Figure 8.1 – Calculating Supply Demand balance
The supply demand balance is evaluated from two perspectives: the “Annual Average” and “Critical
Period” (periods of peak demand).
8.2 The projected Supply Demand balance
Once the effects of climate change and the Habitats Review of Consents are taken into account in the
way described in chapter 7, deficits at some point in the next 25 years are forecast for three WRZs, as
depicted in the following map.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Figure 8.1 Surplus and deficit zones
The three zones53
that are forecast to fall into deficit at some point over the next 25 years are Brecon
– Portis, Pembrokeshire, and SEWCUS. When the full range of UKCP09 climate change scenarios
are incorporated in the “S8” component of Target Headroom, a fourth zone is projected to be in deficit
over the same period, namely North Eryri Ynys Mon.
53
South Meirionnydd zone (Dry Year scenario) is shown to be marginally in deficit from 2029-30 onwards, to a maximum deficit
value in 2034-35 of 0.08 Ml/d (80 m3/d). Given the marginal nature of this deficit late in the planning period and that significant
revisions to the water resources planning process are to be undertaken over the next 12 months by Welsh Water (e.g. demand forecast update, review and update of inflows) it is not considered necessary or appropriate to subject South Meirionnydd to a full options appraisal at this time to mitigate against this deficit. Naturally, following the WRMP updates over the next 12 months, should South Meirionnydd be in deficit, then a full options appraisal will be completed for the March 2013 Draft Plan.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Table 8.1 below summarises the position for these three zones:
Zone Reduction in
DO (Ml/d) Enters Deficit
Deficit by 2035 (Ml/d)
Primary reason
Brecon-Portis 3 2020 1 Habitats Directive
Pembrokeshire 19 2017 13 Climate Change and Habitats Directive
SEWCUS 85 2028 12
Climate Change and Habitats Directive
Table 8.1 – Supply Demand Deficits
Table 8.2 summarises the position for the four zones that are projected to go into deficit when the full
range of UKCP09 climate change scenarios is incorporated into the S8 component of Target
Headroom.
Zone Reduction in
DO (Ml/d) Enters Deficit
Deficit by 2035 (Ml/d)
Primary reason
Brecon-Portis 3 2020 1 Habitats Directive
Pembrokeshire 19 2015 19 Climate Change and Habitats Directive
SEWCUS 85 2020 104
Climate Change and Habitats Directive
North Eryri Ynys Mon
9 2019 5 Climate Change
Table 8.2 – Supply Demand Deficits with the full range of UKCP09 climate change scenarios
incorporated into the S8 component of Target Headroom
8.3 Brecon Portis
The projected deficit in this zone is driven wholly by the incorporation into our forecasts of the
abstraction licence reductions required by the Environment Agency in the light of the Habitats
Directive. As a result of these changes the volume of water we can abstract from the Brecon
boreholes is reduced under low flow conditions in the River Usk. This means that during dry periods,
when generally we see higher demands, our abstractions would be curtailed and we would be unable
to meet demand.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Figure 8.2 – Brecon / Portis Supply Demand
As noted in chapter 7 above, the supply demand deficit in this zone is unaffected if the full effects of
UKCP09 climate change projections on Target Headroom are taken into account.
8.4 Pembrokeshire
The calculated deficit in this zone is also driven primarily by the incorporation into our forecasts of the
abstraction licence reductions required by the Environment Agency in the light of the Habitats
Directive. As a result of these measures the volume of water we can abstract from our intakes on the
Eastern and Western Cleddau rivers is severely reduced, particularly at Pont Hywel which would be
rendered virtually unusable as a result of the licence changes proposed by the Environment Agency
Wales during periods characterised by low flows and high demand. As a result, we would be unable
to maintain storage levels in Preseli reservoir and could not, therefore, meet the demands placed on
Preseli Water Treatment Works.
We have also modelled the impacts of the UKCP09 climate change projections. As with the Usk and
the Wye, lower rainfall leads to lower river flows which means that the thresholds at which we have to
reduce our abstractions from the Eastern and Western Cleddau rivers are reached sooner and more
frequently thus exacerbating further the reductions in the availability of water. Inflows to our
reservoirs are also reduced and so storage levels are lower.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Figure 8.3 – Pembrokeshire Supply Demand
As noted in chapter 7 above, if the full range of UKCP09 climate change scenarios is taken into
account in Target Headroom, the calculated deficit in this zone increases from 12.7 Ml/d to 18.2 Ml/d
by 2035. This is illustrated in Figure 8.4 below. Section 9.7 below presents broad details of how this
would affect our strategy for achieving supply demand balance in this zone.
Figure 8.4 – Pembrokeshire Supply Demand incorporating the full effects of UKCP09 climate
change scenarios
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8.5 South East Wales Conjunctive Use System (SEWCUS)
The deficit in this zone is primarily calculated on the basis of the Environment Agency‟s review of our
relevant licences, but the effect of UKCP09 climate change scenarios on Deployable Output further
exacerbates the position, and by 2035 there is a projected deficit of some 12 Ml/d.
Figure 8.5 – SEWCUS Supply Demand
As noted in chapter 7 above, if the full range of UKCP09 climate scenarios is taken into account in
Target Headroom, the deficit in this zone increases from 12.4 Ml/d to 104.2 Ml/d by 2035. This is
illustrated in Figure 8.6 below. Section 9.7 below presents broad details of how this would affect our
strategy for achieving supply demand balance in this zone.
Figure 8.6 – SEWCUS Supply Demand incorporating the full effects of UKCP09 scenarios
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
8.6 North Eyri Ynys Mon
Under our preferred approach to the treatment of climate change uncertainty, this zone remains in
surplus throughout the Plan period. However, if the full range of UKCP09 climate scenarios is taken
into account in Target Headroom, the projected surplus of 2.9 Ml/d in 2035 becomes a deficit of 4.3
Ml/d. This is illustrated in Figure 8.7 below. Section 9.7 below presents broad details of how we
would expect to address this.
Figure 8.7 – North Eryri Ynys Mon Supply Demand incorporating the full effects of UKCP09
climate change scenarios
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Chapter 9. Option Appraisal
In Chapter 8 we presented details of the three zones where we are projecting that at some point
during the next 25 years demand will exceed the available water supply and the zone will enter deficit.
This chapter explains how we evaluate the options available to address those deficits. We also
provide in section 9.7 an overview of how we would address the bigger deficits in Pembrokeshire and
South East Wales Conjunctive Use System zones on the basis of more “pessimistic” projections that
take into account the full range of UKCP09 climate scenarios, together with details of the options for
address the deficit that would emerge on this basis in North Eyri Ynys Mon. We have not appraised
the options for meeting supply demand deficits on the basis of an “optimistic” view of the effect of
climate change on Target Headroom.
To maintain our relevant Level of Service, both at a company level and in each of the two WRZs, we
either need to increase supply or reduce demand (or a combination of the two). Without such
intervention these zones may experience a frequency of water restrictions such as hosepipe bans in
excess of what we have established as the minimum level of service.
9.1 Our approach to appraising the options
9.1.1 Overall methodology
Our option appraisal approach follows national best practice and is consistent with the requirements
of the Environment Agency‟s Guideline.
The most important reference document on option appraisal is “The Economics of Balancing Supply
and Demand” (EBSD) (UKWIR/EA 2002). The EBSD report sets out how water companies should
identify, assess and compare alternative options for addressing supply demand deficits. In
accordance with the Environment Agency‟s Guideline we have also used:
Assessment of Benefits for Water Quality and Water Resources Schemes in the PR04
Environment Programme (EA, 2002), commonly referred to as the Benefits Assessment
Guidance (BAG). This methodology provides non-prescriptive guidance on how to assess the
environmental and social costs of options; and
Providing Best Practice Guidance on the Inclusion of Externalities in the Economic Level of
Leakage Calculation (Ofwat, 2007). This report provides guidance on how to assess the
environmental and social costs of leakage reduction schemes.
9.1.2 Environmental Appraisal
Following the adoption of the Environmental Assessment Directive54
in 2004, it is now a statutory
requirement to undertake a Strategic Environmental Assessment of the measures contained within
the Plan. The purpose of such an Assessment is to identify the environmental, economic and social
effects of each option. Our Strategic Environmental Assessment is presented in Chapter 10.
In addition, to ensure that the options we propose have “no adverse effect” upon European
designated Natura 2000 sites, we have also completed a Habitats Regulations Assessment.55
We
54
Directive 2001/42/EC.
55 Schedule 1 of the Conservation (Natural Habitats, &c) Regulations 1994 (as amended) (the „Habitats Regulations‟) requires
that competent authorities assess the potential impacts of land use plans on the Natura 2000 network of European protected sites.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
have elected to undertake this assessment in order to demonstrate that, when implemented, the Final
Plan will not have adverse effects on any designated sites. Full details of the Habitats Regulations
Assessment can be found in Chapter 10.
9.1.3 The unconstrained list of options
For each WRZ where a deficit has been predicted we have prepared an “Unconstrained” list of
options. This represents an exhaustive list of all technically feasible options that could potentially
redress the supply demand balance deficit. The Economics of Balancing Supply and Demand report
sets out the range of options that should be considered and summarises them into four main
categories:
Distribution Management - options which reduce consumption from the point of input into
the network to the customer property (leakage options and mains replacement);
Customer-side Management - options which reduce customers‟ consumption (water
efficiency and tariffs);
Production Management - options which reduce/modify usage from where it is abstracted to
where it enters the network; and
Resource Management - options that vary yield.
We have undertaken a full up-to-date appraisal of options across these four categories. This ensures
that every type of option has been duly considered. The range of sub-options within the above four
categories is described in the report on the Economics of Balancing Supply and Demand56
9.2 Identifying the feasible options
A Multi-Criteria Analysis57
was applied using 10 criteria grouped into the broad categories of
Technical, Potential and Achievability, to refine the unconstrained list into a shorter “Feasible” list of
options.
The Multi-Criteria Analysis was undertaken on every Customer-side, Resource, and Production
Management option to review how each compared against a number of key environmental,
engineering and technical criteria, as specified under the Economics of Balancing Supply and
Demand report approach. Additional environmental categories for the Resource and Production
Management options were added to this analysis to improve our understanding of how each option
could impact the environment. One of these categories is the inclusion of the results of the
assessments the Environment Agency undertook for their Catchment Abstraction Management
Strategy into what water, if any, is available for abstraction across the surface and groundwater
catchments of Wales. Full details of this work are set out in our supporting Engineering Report.
56
“.
57 Multi Criteria Analysis is a common and accepted technique for making a comparative assessment of options, taking account
of several criteria simultaneously. It is mainly used to assess impacts that cannot be readily quantified in monetary terms.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
9.3 Feasible List
9.3.1 Resource and Production Management
From the Multi-Criteria Analysis process described above a total of 19 Resource and Production
Management options across the three zones were assessed as “Feasible” and carried forward for
more detailed analysis. For each we have determined:
Capital expenditure (CAPEX);
Design, planning and construction time (the lead time);
Operational expenditure (OPEX);
Gain in zonal Deployable Output or the savings in demand;
Environmental and social costs and benefits (including carbon impact); and
Average Incremental Social Costs.58
9.3.2 Customer-side and Distribution Management
From the Multi-Criteria Analysis process a total of 18 Customer-side Management options across the
three zones were assessed as Feasible and carried forward. These consisted of five “water
efficiency” options and one “tariff” option. Water savings and costs were calculated for each measure,
the effect of which was then quantified for each zone using relevant figures for the number of
properties and population.
For the water efficiency measures, we have assumed that implementation takes place over a ten year
programme, and that water savings are effective for 10 years, in line with manufacturers‟
recommendations of an average 10 year lifespan for water efficiency products. Therefore, the
measures were designed so that maximum penetration of each measure would be achieved at the
end of the 10-year programme.
In addition we have also included, for the Pembrokeshire and South East Wales Conjunctive Use
System (SEWCUS) WRZs, three Distribution Management (leakage) options. These successively
more intensive leakage control strategies essentially reduce leakage levels below the short run
Economic Level of Leakage, and can be characterised as follows:
1. Reductions in detected leak run times – this option essentially increases the amount of
leakage detection resource available;
2. Location, operation and sounding of all fittings - this option targets previously undetected
leakage from all fittings, not just those that are visible without excavation; and
3. Installation of permanent correlator noise loggers – this option helps leakage teams to
detect leaks quicker and to identify those leaks not usually detected through conventional
means.
These leakage options would ideally, but not necessarily, be implemented in sequence i.e. option 1
followed by 2 then 3, as each option involves progressively intensive actions and manpower. The
58
Average Incremental Social Cost is a measure of the overall financial, environmental and social cost of an option. It is
usually expressed in terms of pence per cubic metre of water (p/ m3).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
costs and savings for each option have been estimated based on the manpower and capital
requirements.
59
Tables 9.160
, 9.2 and 9.3 present the feasible options and their respective total environmental, social
and financial costs, for the three zones. They also show the potential water volume benefit for each
option, enabling Average Incremental Social Costs to be calculated and the cost-effectiveness of
each option to be compared. For example, the raising of the Llys Y Fran dam option for the
Pembrokeshire WRZ has a comparatively high Average Incremental Social Costs value of 606p/m3
and is the most expensive Resource and Production Management option for this zone.
The primary feasible option shown for the Brecon – Portis WRZ is “River regulation from Usk
reservoir”. We have considered water efficiency options, but as a result of the small size of this zone
these would not yield sufficient volumes to meet the deficit. The “River regulation from Usk reservoir”
option has been discussed with and has the approval of the Environment Agency.
The Average Incremental Social Costs values indicate the relative unit costs of each option but the
overall least cost solution depends on the optimal schedule of interventions over time that best
addresses the profile of the supply-demand deficits. Consequently, the most economic plan may not
directly reflect the Average Incremental Social Costs (AISC) ranking.
Option reference and name DO benefit
(Ml/d) AIC (p/m3)
Env and social
cost (p/m3)
AISC
(p/m3)
8206.1, Re-instate Milton source for
industrial 14.0 278 40 318
8206.3, Dam raising of Llys y Fran 14.4 606 26 632
8206.5, Increased groundwater abstraction
at Pendine 12.4 236 42 278
8206.6, Upgrade Middle Mill Water
Treatment Works 9.8 179 49 229
8206.7, Re-instate Parc springs 10.3 221 61 282
8206.9, Desalination Pembrokeshire WRZ 19.1 526 120 646
8206.10, Abstraction from the Afon Taf 19.1 391 67 458
8206.11, Transfer water from Bolton Hill
Water Treatment Works to Preseli Water
Treatment Works
8.9 132 32 164
8206.6 Ef, Tariff Option – Metering 0.01 78,013 - 78,013
8206.1 Ef, Household - Home Visit
Package 0.01 112,177 31,130 143,307
8206.2 Ef, Household - Water Butts 0.04 2951 7 2,958
8206.3 Ef, Non Household Visit Package 17.0 826 176 1,002
59
“
60 Options 8206.1 to 8206.10 also require the employment of option 8206.11 to realise the full potential increase in deployable
output. Therefore, for these options, the Deployable Output Benefit, capital expenditure, operating expenditure (and hence Average Incremental Costs and Average Incremental Social Costs values) contain option 8206.11, although not specifically stated in Table 9.1.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Option reference and name DO benefit
(Ml/d) AIC (p/m3)
Env and social
cost (p/m3)
AISC
(p/m3)
8206.4 Ef, Non Households Audits 33.0 2,567 45 2,612
8206.7 Lk, Leakage Option 1 0.5 1,412 10 1,422
8206.8 Lk, Leakage Option 2 0.8 944 58 1,002
8206.9 Lk, Leakage Option 3 2.7 1,803 114 1,916
Table 9.1 - Feasible options, Pembrokeshire WRZ
Option reference and name DO benefit
(Ml/d) AIC (p/m
3)
Env and social
cost (p/m3)
AISC (p/m3)
8108.4, River regulation from Usk reservoir 1.0 26 33 59
Table 9.2 - Feasible options, Brecon - Portis WRZ
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Option reference and name DO benefit
(Ml/d) AIC (p/m
3)
Env and social
cost (p/m3)
AISC
(p/m3)
8121.1, Increase zonal transfer from Tywi
Gower in combination with Schwyll option 22 426 748 1,174
8121.5b, New abstraction, S.E.Wales
groundwater resource, new Water
Treatment Works
35.3 427 56 482
8121.7, Dam raising at Craig Goch 200 121 4 125
8121.11, Re-instate Grwyne reservoir with
new Water Treatment Works 5.9 319 6 325
8121.12, Utilisation of Grwynne as Usk
compensating reservoir 3.9 9 -26 -17
8121.13, Re-instate Wentwood reservoir
with new Water Treatment Works 7.8 309 27 336
8121.14, Reinstate treatment for Ynys y Fro
and Pant yr Eos reservoirs 10 284 848 1,132
8121.15, Reinstate the Bwllfa Graig Water
Treatment Works 5.5 363 715 1,078
8121.20, Desalination SEWCUS WRZ 10 650 222 872
8121.21, Reinstate Clydach reservoir and
Perthcelyn Water Treatment Works 5 365 2,205 2,570
8121.6 Ef, Tariff Option - Metering 0.3 34,935 - 34,935
8121.1 Ef, Household - Home Visit
Package 22.1 450 165 615
8121.2 Ef, Household - Water Butts 0.04 18 0.04 18
8121.3 Ef, Non Household Visit Package 11.2 335 71 407
8121.4 Ef, Non Households Audits 21.5 799 14 813
8121.7 Lk, Leakage Option 1 3.9 1,270 9 1,278
8121.8 Lk, Leakage Option 2 12.9 852 52 904
8121.9 Lk, Leakage Option 3 20.6 1,587 100 1,687
Table 9.3 - Feasible options, South East Wales Conjunctive Use System (SEWCUS) WRZ
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
9.4 Environmental and Social costing
As noted above, the environmental and social costs of each option are taken into account in deriving
the optimal strategy for addressing supply demand deficits, in accordance with the Environment
Agency‟s guidance.61
We divide environmental and social impacts into those that are water-related
(primarily changes in river flows) and those that are non-water related, such as the effects of
construction works and use of energy.
Full details of the Environmental and Social costing can be found in our supporting Engineering
Report.62
We have also made a separate assessment of carbon emissions. This is a new element of Water
Resources Management Plans.63
In carrying out this analysis we have distinguished between
embedded carbon emissions resulting from construction activities such as the processing of raw
materials, transport, waste removal etc, and operational carbon emissions that arise both directly and
indirectly from our own activities.
The graph below shows an example of the output of this analysis. Full details of the carbon
accounting process can be found in the technical supporting document.64
Figure 9.1 – Carbon Costing in Pembrokeshire
We have also assessed the operational carbon impact of the preferred options on the estimated
Company operational carbon footprint for water services. This is shown in Figure 9.2. Actual (out-
turn) data is shown in blue along with forecasted data (in red), based on our year on year reduction
61
Benefits Assessment Guidance: EA, 2002. 62
“Water Resource Options Assessment, Revised Draft”: Welsh Water, April 2011. 63 The requirement to undertake carbon accounting is set out in the joint Defra / Welsh Government Water Resources
Management Plan Direction 2007. 64 Carbon accounting of the Water Resources Management Plan (Halcrow 2009).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
target of 3% per year. The actual and the forecast data has been „uplifted‟ to represent Dry Year
scenario outputs as the original forecast was based on a „normal‟ year. This was undertaken to allow
direct comparison with, and inclusion of, the preferred options which emerge under the Dry Year
scenario.
The forecast data also takes into account that from 2020-21 onwards our operations will be
significantly influenced by the changes to our existing licences under the Habitats related consents
review. The forecast data has been adjusted accordingly. The implementation of the preferred
options are shown cumulatively on top of the forecast data.
Figure 9.2 Operational carbon impact of the Preferred options over and above the Company
total footprint
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
9.5 Selecting the preferred option
To select the preferred option(s) for each zone we added the financial costs to the environmental and
social costs to arrive at an overall Average Incremental Social Costs estimate. Using a bespoke
mathematical least cost planning model65
we then derived the least cost combination of options that
would meet the deficits under both the Annual Average and Critical Period planning scenarios. This is
explained further in section 9.6 below. Annex 4 provides details of the ranking of options for the three
deficit zones.
9.6 Optimisation model
The optimisation model calculates the supply demand balances, from the individual components, for
each WRZ then evaluates the least cost combination of options, from the range of options and cost
data, which could be implemented to meet the forecast deficits. The model:
determines the Average Incremental Cost & Average Incremental Social Cost for each option;
identifies the least-cost combination/ mix of options that best meets the supply demand deficit
for each WRZ; and
derives the Preferred set of options that meets the supply demand balance deficit, for each
WRZ, at the least long-run marginal cost.
The model has been developed to allow changes in the various components of the supply demand
balance to be rapidly incorporated to take account of, for example, potential climate change scenarios
and sustainability reductions.
The model allows for the identification of options links and dependencies. For example, the model will
only select one option, if programmed to do so, where multiple source options have been identified to
supply one Water Treatment Works, or, where there are transfers from one source to multiple WRZ‟s.
The model also includes a Geographic Information System (“GIS”) interface that allows the options to
be visualised and their relationship, for example, with existing Welsh Water infrastructure and their
proximity to environmentally sensitive areas.
As the Preferred option set will likely form the basis of the Plan submission, the model also produces
the optimisation run results in the required format for Tables WRP2 and WRP3, as required by the
Agency‟s Guideline.
To reiterate, the Average Incremental Social Cost values indicate the relative unit costs of the options
but the least-cost solution depends on the optimal schedule of options over time that best satisfies the
supply-demand deficit profile. Consequently, the most economic plan may not necessarily directly
reflect the Average Incremental Social Costs ranking, as shown in Tables 9.1, 9.2, 9.3 and 9.13,
which show the Average Incremental Social Costs based on the maximum capacity of the options and
not the Utilised capacity of the option (to meet the specific zonal deficit).
65
“Lot 5 – Least Cost Water Resources Planning Model – Functional Description” (Jacobs 2008a), and “Lot 5 – Least Cost
Water Resources Planning Model – User Guide” (Jacobs 2008b).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
9.7 Preferred Options for Addressing Supply Demand Deficits (Without Incorporating the Full Range of UKCP09 Climate Scenarios in Target Headroom)
9.7.1 Pembrokeshire
The options that have been selected on a least cost basis for this zone, which meet the deficits under
both the Annual Average and Critical Period scenarios, are presented in Table 9.4. Further detail of
what these options entail is contained in Table 9.5.
Option No.
and Name
Implementation
date
/Deployable
Output benefit
Capital
Expenditure
(£M)
Annual
Operating
Expenditure
(£M)
Net Present
Value of
Capital
Expenditure
and
Operating
Expenditure
(£M)
Net
Present
Value of
Env and
Social
costs
(£M)
Total
Net
Present
Value
(£M)
8206.1,
Reinstate
Milton
source for
industrial
use &
8206.11,
Transfer
water from
Bolton Hill
Water
Treatment
Works to
Preseli
Water
Treatment
Works
(implement
ed as an
aggregated
solution)
2017
14.0 Ml/d 12.3 0.5 15.1 1.4 16.5
Table 9.4 Preferred solution (on least cost basis) for Pembrokeshire WRZ
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
8206.1, Reinstate Milton
source for industrial use
Milton Borehole, located 3km from Carew, is an emergency source that is
only made operational to supplement the potable supply from Bolton Hill
Water Treatment Works during periods of high demand.
Water would be abstracted and softened in a new 8Ml/d Water Treatment
Works and blended with existing supplies.
The water would be used to deliver water to the industrial supplies in the
area thereby releasing water currently abstracted from the Eastern Cleddau
for distribution in the wider WRZ.
8206.11, Transfer water
from Bolton Hill Water
Treatment Works to
Preseli Water Treatment
Works
Bolton Hill Water Treatment Works near Haverfordwest is currently
supplied with water from the Eastern and Western Cleddau; Preseli Water
Treatment Works is mainly supplied from Preseli Reservoir supplemented
from an abstraction at Llysyfran.
This option involves upsizing and re-commissioning 10km of mains in and
around Haverfordwest to enable water to be transferred between the two
Water Treatment Works, and building a new water pumping station to allow
water to be moved from the south west of the WRZ to the north east.
Table 9.5 – Pembrokeshire Options
Figure 9.3 shows how these options address the deficit over time.
Figure 9.3 - Preferred solution (least cost) for Pembrokeshire WRZ, Utilised Water Available for Use (Annual Average Dry Year)
9.7.2 Brecon – Portis WRZ
The option that has been selected for this zone is Option No. 8108.4 – “River regulation from Usk
reservoir”, details of which are presented in Table 9.6.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Option No. and
Name
Implementation
date/
Deployable
Output benefit
Capital
Expenditur
e (£M)
Annual
Operating
Expenditure
(£M)
Net Present
Value of
Capital
Expenditure
and
Operating
Expenditure
(£M)
Net
Present
Value of
Env and
Social
costs
(£M)
Total
Net
Present
Value
(£M)
8108.4, River
regulation from
Usk reservoir
2020
1.0 Ml/d 0.3 0 0.2 0.4 0.6
Table 9.6 - Preferred solution (on least cost basis) for Brecon - Portis WRZ
This option involves making additional releases from Usk Reservoir in order to augment river flows
and thereby enable abstraction at Brecon to be maintained at required levels.
9.7.3 SEWCUS WRZ
The options that have been selected on a least cost basis for this zone are presented in Table 9.7.
Further detail of what these options entail is contained in Table 9.8.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Option No.
and Name
Imple-
mentation
date/DO
benefit
Capital
Expenditure
(£M)
Annual
Operating
Expenditure
(£M)
Net Present
Value of
Capital
Expenditure
and Opex
(£M)
Net
Present
Value of
Env and
Social
costs
(£M)
Total
Net
Present
Value
(£M)
8121.11,
Reinstate
Grwyne
reservoir
with new
Water
Treatment
Works
2028
5.9 Ml/d 10.2 0.2 6.3 0.1 6.4
8121.13,
Reinstate
Wentwood
reservoir
with new
Water
Treatment
Works
2032
7.8 Ml/d 12.9 0.2 6.4 0.1 6.5
Table 9.7 Preferred solution (on least cost basis) for SEWCUS WRZ
8121.11, Reinstate
Grwyne reservoir with new
Water Treatment Works
Grwyne Reservoir previously supplied water to the Abertillery area, over 40
km to the south. The reservoir is now mothballed.
This option would construct a wholly new Water Treatment Works to treat
the raw water from the reservoir. Potable water mains have recently been
re-laid so no new mains would be required. This option would provide up
to 6 Ml/d.
8121.13, Reinstate
Wentwood reservoir with
new Water Treatment
Works
Wentwood Reservoir, that previously supplied the south east Gwent
distribution zone, has some algal problems. It is now used for recreation
and fishing.
This option would reinstate Wentwood Reservoir and provide improved
treatment facilities. This option would provide up to 8 Ml/d.
Table 9.8 – SEWCUS Options
Figure 9.4 shows how these options address the deficit over time.
9.7.4 Demand Management and Leakage options
As stated in section 9.6, the options are selected on a least cost basis, in parallel with the
environmental appraisal conducted through the Strategic Environmental Assessment and Habitats
Regulations Assessment (section 10.2 and section 10.3). Although many of the demand
management and leakage options have been appraised as potentially contributing positively to the
environment, in conjunction with the least cost modelling process they have not been selected as the
Preferred options as the demand savings of the options are either not sufficient to meet the deficits –
either because the option demand savings are wholly too low to meet the deficits, or, in the case of
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
the water efficiency options, the ramping up (10 year period) and ramping down (10 year period) of
the demand savings cannot meet the deficits across the full planning period (see section 9.3). Where
demand management and leakage options do have sufficient „yields‟ to meet the deficits, then their
implementation is not cost effective.
Figure 9.4 - Preferred solution (least cost) for SEWCUS WRZ, Utilised WAFU (Annual Average
Dry Year)
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
9.8 Preferred Options for Addressing Supply Demand Deficits, Incorporating the Full Range of UKCP09 Scenarios in Target Headroom
Our preferred options for addressing the deficits that arise when the full effects of UKCP09 scenarios
in Target Headroom are taken into account (see Table 8.2 above) are presented below. The options
for Pembrokeshire and North Eyri Ynys Mon meet the deficits under both the Annual Average and
Critical Period scenarios.
9.8.1 Pembrokeshire
For Pembrokeshire the supply demand deficit that we would have had to address on this basis would
have been somewhat greater, rising to 18.2 Ml/d by 2035 instead of 12.7 Ml/d. Our indicative
preferred options for meeting this shortfall are set out in table 9.9, and further details of the schemes
are set out in table 9.10.
Option No. and
Name
Imple-
mentation
date/DO
benefit
Capital
Expenditure
(£M)
Annual
Operating
Expenditure
(£M)
Net Present
Value of
Capital
Expenditure
and Opex
(£M)
Net
Present
Value of
Env and
Social
costs
(£M)
Total
Net
Present
Value
(£M)
8206.3 Ef, Non
Household -
Non Household
Visit Package
2015
17.0 Ml/d 23.2 0.5 19.0 4.1 23.1
8206.10,
Abstraction from
the Afon Taf &
8206.11,
Transfer water
from Bolton Hill
Water
Treatment
Works to Preseli
Water
Treatment
Works
(implemented
as an
aggregated
solution)
2020
19.1 Ml/d 27.0 0.5 22.6 1.9 24.5
Table 9.9 Preferred solution (on least cost basis) for Pembrokeshire WRZ
8206.3 Ef, Non Household
- Non Household Visit
Package
This water efficiency option targets small businesses, advising on the
efficient use of water and providing water efficient devices, such as, low
water use taps. This option would save up to 17 Ml/d.
8206.10, Abstraction from
the Afon Taf
The Afon Taf originates on the western fringe of the Preseli Hills and flows
southwards, before flowing into Carmarthen Bay, south west of
Carmarthen.
This option would abstract water from the lower reaches of the Afon Taf. A
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
new Water Treatment Works and associated pipeline/ network changes would be required. The option yield is 10 Ml/d.
8206.11, Transfer water
from Bolton Hill Water
Treatment Works to
Preseli Water Treatment
Works
Bolton Hill Water Treatment Works near Haverfordwest is currently
supplied with water from the Eastern and Western Cleddau; Preseli Water
Treatment Works is mainly supplied from Preseli Reservoir supplemented
from an abstraction at Llysyfran.
This option involves upsizing and re-commissioning 10km of mains in and
around Haverfordwest to enable water to be transferred between the two
Water Treatment Works, and building a new water pumping station to allow
water to be moved from the south west of the WRZ to the north east.
Table 9.10 – Pembrokeshire Options
9.8.2 Brecon – Portis WRZ
As explained in section 8.3 above, DO in this zone is considered to be constrained by licence
conditions, so the use of the full range of UKCP09 scenarios in Target Headroom has no incremental
impact. The preferred option is therefore the same as shown in Table 9.6 above.
9.8.3 SEWCUS WRZ
For SEWCUS the supply demand deficit that we would have to address would have been
considerably greater as a result of the use of the full range of UKCP09 scenarios in Target Headroom,
rising to 104.2 Ml/d by 2035 instead of just 12.4 Ml/d. Our indicative preferred options for meeting this
shortfall are set out in table 9.11, and further details of the schemes are set out in table 9.12.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Option No.
and Name
Imple-
mentation
date/DO
benefit
Capital
Expenditure
(£M)
Annual
Operating
Expenditure
(£M)
Net Present
Value of
Capital
Expenditure
and Opex
(£M)
Net
Present
Value of
Env and
Social
costs
(£M)
Total
Net
Present
Value
(£M)
Options
implemented
as a group:
8121.11,
Reinstate
Grwyne
reservoir with
new Water
Treatment
Works
8121.13,
Reinstate
Wentwood
reservoir with
new Water
Treatment
Works
8121.5, New
abstraction,
S.E. Wales
including new
Water
Treatment
Works
8121.15,
Reinstate the
Bwllfa Graig
Water
Treatment
Works
8121.14,
Reinstate
treatment for
Ynys y Fro
and Pant yr
Eos reservoirs
2020
50.8 Ml/d 92.3 6.0 114.0 45.8 159.8
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
8121.8 Locate,
Operate and
Sound All
Fittings
(leakage
option)
2022
12.9 Ml/d 43.8 2.0 36.9 1.5 38.4
8121.3 Ef,
Non
Household -
Non
Household
Visit Package
2026
11.2 Ml/d 14.2 0.3 7.3 1.5 8.8
8121.20,
Desalination
plant
SEWCUS
WRZ
2027
10.0 Ml/d 24.6 1.8 16.7 3.1 19.8
8121.4 Ef,
Non
Household -
Non
Households
Audits
2032
21.5 Ml/d 22.1 1.2 9.2 0.2 9.4
Table 9.11 Preferred solution (on least cost basis) for SEWCUS WRZ
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Options implemented as a
group:
8121.11, Reinstate
Grwyne reservoir with new
Water Treatment Works
8121.13, Reinstate
Wentwood reservoir with
new Water Treatment
Works
8121.5, New abstraction,
S.E. Wales gw resource,
new Water Treatment
Works
8121.15, Reinstate the
Bwllfa Graig Water
Treatment Works
8121.14, Reinstate
treatment for Ynys y Fro
and Pant yr Eos reservoirs
Grwyne Reservoir previously supplied water to the Abertillery area, over 40
km to the south. The reservoir is now mothballed. This option would
construct a wholly new Water Treatment Works to treat the raw water from
the reservoir. Potable water mains have recently been re-laid so no new
mains would be required. This option would provide up to 6 Ml/d.
Wentwood Reservoir, that previously supplied the south east Gwent
distribution zone, has some algal problems. It is now used for recreation
and fishing. This option would reinstate Wentwood Reservoir and provide
improved treatment facilities. This option would provide up to 8 Ml/d.
Investigations have shown that there is a significant amount of groundwater
available from the carboniferous limestone block of south east Wales and
so we plan to utilise this by building a new Water Treatment Works to treat
the abstracted water and deliver the water into the Cardiff/ Newport area.
This option would provide up to 33 Ml/d.
The reservoir at Bwllfa Graig has been out of operation for a number of
years and the associated Water Treatment Works has been de-
commissioned. This option would reinstate the Water Treatment Works
and deliver the water into the supply network. This option would provide up
to 5 Ml/d.
The reservoirs at Ynys y Fro and Pant yr Eos have been out of operation
for a number of years and their associated Water Treatment Works have
been de-commissioned. This option would reinstate the Water Treatment
Works and deliver the water into the supply network. This option would
provide up to 10 Ml/d.
8121.8 Lk, Locate,
Operate and Sound All
Fittings (leakage option)
This leakage option targets previously undetected leakage from all fittings,
not just those that are visible, by increasing the available resources. This
option would save up to 13 Ml/d.
8121.3 Ef, Non Household
- Non Household Visit
Package
This water efficiency option targets small businesses, advising on the
efficient use of water and providing water efficient devices, such as, low
water use taps. This option would save up to 11 Ml/d.
8121.20, Desalination
SEWCUS WRZ
This option would construct a seawater desalination plant. Treated water
would be transferred to an existing Water Treatment Works or service
reservoir for blending with alternative supplies. This option would save up
to 10 Ml/d.
8121.4 Ef, Non Household
- Non Households Audits
This water efficiency option targets large businesses advising on the
efficient use of water, specifically related to their processes, and
recommending alternative water efficient engineering solutions. This option
would save up to 22 Ml/d.
Table 9.12 – SEWCUS Options
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
9.8.4 North Eyri Ynys Mon WRZ
For North Eyri Ynys Mon, the surplus that we had been forecasting turns to a deficit of 4.3 Ml/d by
2035. Table 9.13 presents the Feasible options and their respective total environmental, social and
financial costs for this zone.
Option reference and name DO
benefit (Ml/d)
AIC (p/m3)
Env and social cost (p/m
3)
AISC (p/m
3)
8001.3, Connect Afon Rhythallt to Cwellyn Water Treatment Works
10.93 60.67 2.04 62.71
8001.4, New Crug Water Treatment Works and utilisation of existing Afon Rhythallt source
11.90 98.53 53.21 151.74
8001.5, New abstraction at Llyn Cowlyd and upgrade Mynydd Llandygai Water Treatment Works
9.15 136.93 8.50 145.43
8001.6, New abstraction at Llyn Cowlyd - new Water Treatment Works
8.49 266.75 68.97 335.72
8001.7, Licence Variation at Llyn Cwellyn and Cwellyn Water Treatment Works upgrade
7.06 109.76 0.48 110.24
8001.8, Utilisation of abstraction from Afon Seiont - upgrade Mynydd Llandygai Water Treatment Works
9.15 143.43 11.42 154.85
8001.10, Dam Raising Ffynnon Llugwy 10.01 170.16 1.98 172.14
8001.11, Desalination North Eryri/Ynys Mon WRZ
10.58 289.3 92.67 381.97
8001.6 Ef, Tariff Option - Metering 0.02 51,301.16 - 51,301.16
8001.1 Ef, Household - Home Visit Package
2.22 110.92 31.97 142.89
8001.2 Ef, Household - Water Butts 0.04 8.64 0.02 8.66
8001.3 Ef, Non Household Visit Package 3.23 104.9 22.82 127.72
8001.4 Ef, Non Households Audits 6.33 338.84 6.05 344.89
8001.7 Lk, Leakage Option 1 0.38 1274.92 8.87 1,283.79
8001.8 Lk, Leakage Option 2 1.94 1586.63 100.19 1,686.82
Table 9.13 Feasible options, North Eyri Ynys Mon
Our indicative preferred options for meeting this shortfall are set out in table 9.14, and further details
of the schemes are set out in table 9.15.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Option
No. and
Name
Imple-
mentation
date/DO
benefit
Capital
Expenditure
(£M)
Annual
Operating
Expenditure
(£M)
Net Present
Value of
Capital
Expenditure
and Opex
(£M)
Net
Present
Value of
Env and
Social
costs
(£M)
Total
Net
Present
Value
(£M)
8001.3,
Connect
Afon
Rhythallt
to Llyn
Cwellyn
2019
10.9 Ml/d 4.1 0 3.3 0.2 3.5
Table 9.14 Preferred solution (on least cost basis) for North Eyri Ynys Mon WRZ
8001.3, Connect Afon
Rhythallt to Llyn Cwellyn
Afon Rhythallt drains the Padarn and Peris lakes at Llanberis. An existing
intake at Crawia weir near Llanrug previously abstracted water to Crug
Water Treatment Works, near Caernarfon. Crug Water Treatment Works is
now abandoned.
This option would abstract water from Afon Rhythallt and transfer the water
to Cwellyn Water Treatment Works, which has been upgraded as part of
Welsh Water‟s AMP 5 Quality Programme and would enable the increased
flows to be managed. This option has a yield of 3.4 Ml/d.
Table 9.15 – North Eyri Ynys Mon Options
The above Preferred option for North Eyri Ynys Mon has been selected by our least cost model in line
with the comments in section 9.8.4.
In summary, the options we have identified to address the deficits in these four zones on this basis
would cost some £200m in Net Present Value terms, and would add approximately £20 per annum to
the average household bill for water supply in our area.
9.9 Sensitivity
Our Plan is based on detailed studies, calculations and expert opinion about future outcomes. It is
critical to consider the sensitivity of the Plan to any changes to demonstrate the robustness and
flexibility of the Plan. We have examined:
sensitivity of the supply-demand balances to changes in data; and
sensitivity of the strategy to changes in the options.
9.9.1 Changes in data
Target Headroom (see Chapter 5) enables the quantification of a wide range of potential uncertainties
and includes some allowance for them in the supply-demand balance calculations. This is generally
particularly critical for the potential impact of climate change on source yields and uncertainty in future
demand (although we have detailed our approach regarding climate change earlier in the Plan).
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Actual demand for water is likely to vary from forecast levels due to uncertainties about future
conditions outside of Welsh Water‟s control, such as population changes and economic trends.
To some degree the water resources management plan process is able to accommodate these risks,
as the Plan is updated every five years. For example, within that five year period, demand forecasts,
climate change impacts, changes in source yields, are all revised and updated. This ensures in
theory, that the Plan at any given point in time is robust, flexible and up to date.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
9.9.2 Changes in Levels of Service
For the three deficit zones of SEWCUS, North Eyri Ynys Mon and Pembrokeshire we have also
undertaken an analysis of varying the Level of Service of the baseline models to ascertain the impact
of Deployable Output. The results are shown in Table 9.16.
WRZ Deployable
Output (Ml/d)
LoS
(years)
Hosepipe
Bans (no.)
Demand
shortfalls Other comments
SEWCUS
401.75 1 in 33 0 0 Llandegfedd
reservoir at 20%
409.57 1 in 33 0 0 Llandegfedd
reservoir at 15%
421.38 1 in 33 1 0 Llandegfedd
reservoir at 7%
429.00 1 in 8 4 0 Llandegfedd
reservoir at 1%
NEYM
50.86 1 in 24 2 0 -
51.52 1 in 15 3 2 -
52.88 1 in 15 3 14 -
Pembrokeshire
64.76 1 in 36 1 0 -
65.03 1 in 18 2 0 -
65.31 1 in 12 3 0 -
Table 9.16 Deployable output sensitivity to LoS (SEWCUS, NEYM and Pembrokeshire WRZ)
The baseline Deployable Output value for SEWCUS is 401.75 Ml/d, under which no Hosepipe Bans
occur and Landegfedd reservoir storage continues to comply with Emergency Storage requirements.
The Deployable Output in the zone can be increased, still with no Hosepipe Bans, to 421.38 Ml/d (5%
increase), but storage levels in Landegfedd reservoir fall to 7% which does not comply with
Emergency Storage requirements. The Deployable Output in the zone can be increased further still
to 429 Ml/d (7% increase) on the basis that 4 Hosepipe Bans will occur in a 33 year period (resulting
in a LoS for the zone of 1 in 8 years) but with Landegfedd reservoir storage falling to 1% in the critical
year.
For the North Eyri Ynys Mon Water Resource Zone, the Deployable Output can only be increased to
52.88 Ml/d (increase of 4%) by lowering the Level of Service to 1 in 15 years and incurring a number
of demand failures. For the Pembrokeshire Water Resource Zone the Deployable Output can only be
increased to 65.31 Ml/d (increase of <1%) by lowering the LoS to 1 in 12 years.
In summary, for the small gains in Deployable Output in each zone and the considerable risk to
security of supply, we do not consider that varying the zonal Level of Service and potentially imposing
restrictions on our customers on a more frequent basis is justified.
9.9.3 Changes in the options
This Plan has identified preferred solutions which are likely to form part of the overall strategy. For
each option we have allowed sufficient investigation time and costs. Therefore, we are not
anticipating that the list of resource options will change.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
However, during the investigation phase should, for example, an environmental issue arise that would
rule out that option, then we assessed what other options would be selected as part of the Preferred
solution. In preparing the Plan, this was a major concern for the Countryside Council for Wales and
Natural England who, rightly, required us to demonstrate that should an option at detailed project
stage prove to have a likely adverse impact on protected environmental sites or species, that we
could implement alternative options to maintain the supply demand balance. This is detailed in the
Strategic Environmental Assessment and the Habitats Regulations Assessment reports.
For the deficit zones of SEWCUS and Pembrokeshire, should at least one of the options need to be
excluded, then we have itemised, in Table 9.17 the next alternative preferred solutions.
SEWCUS Pembrokeshire
Preferred
option
excluded
8121.11, Reinstate Grwyne reservoir with new Water
Treatment Works
8206.1, Reinstate Milton
source for industrial use
Alternative
options
selected
8121.13, Reinstate Wentwood reservoir with new
Water Treatment Works
8121.15, Reinstate the Bwllfa Graig Water Treatment
Works
8206.10, Abstraction
from the Afon Taf
Table 9.17 Alternative Preferred options
Due to the geography of Wales, some of the preferred options naturally have high Operating
Expenditure due to increased pumping requirements. We have undertaken sensitivity on the choice
of preferred solutions for each deficit zone, should the Operating Expenditure estimates of the
feasible list of options prove to be different from that currently estimated. If we increase the Operating
Expenditure costs of all the feasible options by 20%, then the same preferred options are still
selected.
Through the Revised Draft Plan consultation we are anticipating that consultees will suggest
alternative options that we not have considered fully. For these reasons there may be changes to the
scope, cost or feasibility of some of the options in our Final Plan. However, we expect the final
solutions to be broadly similar in nature. This is due to the size of the deficits and the low cost
effectiveness of some of the demand management measures.
Naturally if we do change or include further options between now and the Final Plan, the changes will
be fully documented in the Final Plan.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Chapter 10. Environmental Appraisal
10.1 Introduction
This chapter presents the work we have undertaken to identify and assess the potential effects of our
Plan on the environment. It describes how we have undertaken this assessment, the results of that
assessment, and any further work that we need to carry out.
Overall, the environmental appraisal shows that our Plan, and specifically the Preferred Options, are
not expected, at this stage, to have any significant environmental impacts. However, in the event that
any of our preferred options are found to have significant environmental impacts once we reach the
stage of detailed investigations and scheme design, we have identified a number of alternative
options that could be implemented instead.
10.1.1 Strategic Environmental Appraisal
Under the Plan we have identified the most economic (least cost) combinations of options to meet the
predicted supply shortfalls over the next 25 years. In doing so we included, within the costing
process, the potential environmental and social costs of each option.
In addition to this, we have prepared a Strategic Environmental Assessment. This Assessment is a
statutory process66
that identifies and assesses potentially significant environmental effects of the
Plan, and, where appropriate, how negative impacts might be mitigated and positive impacts
enhanced.
10.1.2 Habitats Regulations Assessment
In addition to carrying out a Strategic Environmental Assessment, we have also assessed the
potential impacts of this Plan against the conservation objectives for designated European sites.67
This is known as a Habitats Regulations Assessment 68
and is driven by the Habitats Directive.69
The Habitats Regulations Assessment determines whether there will be any “likely significant effects”
on any European site as a result of the implementation of the Plan (either on its own or “in
combination” with other plans or projects) and, if so, whether these will adversely affect the integrity of
the site.
The Habitats Regulations Assessment, like the Strategic Environmental Assessment, has been an
integral part of the development of the options from the outset and hence this Revised Draft Plan. In
essence, the Strategic Environmental Assessment and Habitats Regulations Assessment process
proceed alongside one another (and alongside the WRMP process) with the outcomes of the Habitats
Regulations Assessment being incorporated into the Strategic Environmental Assessment
66
The Water Industry, through UK Water Industry Research Ltd (UKWIR) recognises that WRMPs may be subject to a SEA
under the requirements of the European Directive 2001/42/EC (the SEA Directive). The SEA Directive has been transposed into UK legislation as Regulations. 67
HRA is required by law for all European Sites (Regulation 48). A European Site is any classified SPA and any Special Area
of Conservation from the point where the Commission and the Government agree the site as a Site of Community Importance. HRA is also required, as a matter of Government policy, for potential SPAs, candidate Special Areas of Conservation and listed Ramsar Sites for the purpose of considering development proposals affecting them (PPG9 paras. 13 and C7). As such, pSPAs, cSpecial Areas of Conservation and Ramsar Sites must also be considered by any HRA. Within this report „European site‟ is used as a generic term for all of the above designated sites 68
Appropriate Assessment‟ has been historically used as an umbrella term to describe the process of assessment as a whole.
The whole process is now more accurately termed „Habitats Regulations Assessment‟ (HRA), and „Appropriate Assessment‟ is used to indicate a specific stage of a HRA. 69
Council Directive 92/43/EEC on the conservation of natural habitats and of wild fauna and flora.
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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011
Environmental Report. The approach we took to carrying out the Habitats Regulations Assessment is
described in Section 10.3.
10.1.3 Consultation
We have worked closely with the Countryside Council for Wales and Natural England in preparing
both the Strategic Environmental Assessment and the Habitats Regulations Assessment, and have
discussed with them our approach to undertaking the environmental appraisal, the evaluation of the
preferred options, and the format of the Strategic Environmental Assessment and Habitats
Regulations Assessment reports. We believe that through this process we have achieved a robust
and appropriate appraisal of the potential environmental impacts of the Plan.
We intend to continue working closely with both the Countryside Council for Wales and Natural
England through the consultation process on this Revised Draft Plan, and in preparing the Final Plan.
10.2 Strategic Environmental Assessment
10.2.1 Environmental Baseline
Defining the environmental baseline, relevant issues and the context is important in setting the
framework for the Strategic Environmental Assessment. It involves the following elements:
characterising the current state of the environment (including social and economic aspects);
and
identifying existing problems and opportunities to be considered in the Plan.
Based on an analysis of up-to-date relevant information, we have identified the key sustainability
issues (or Themes) in the Welsh Water region, for example, “Water” and “Air and Climate”. Within
these broad Themes we have then assessed all the Feasible Options against key Objectives (eleven
in total) to determine the potential impact that each option, individually and in combination, may have
on the environment.
Examples of the Objective questions are:
ensuring sustainable use of water resources, and
promoting the wise use of resources.
Each of the feasible options was assessed against the Objectives to identify its potential impacts.
These were assessed on the basis of the nature of the effect, its timing and geographic scale, the
sensitivity of the people or environmental receptors that could be affected, and how long it might last.
The Strategic Environmental Assessment Environmental Report fully details the Themes, Objectives
and assessments for each of the deficit WRZs.70
10.2.4 Summary of impacts
In general, the assessment found that the options involving larger programmes of work or yielding
more water tended to have the biggest impacts (both positive and negative) across the range of
70 “Strategic Environmental Assessment of Revised Draft WRMP, Revised Environmental Report”: Entec UK Limited, March
2011.
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Objectives. This reflected, for example, the greater use of resources during construction and the
more significant effect on security of supply.
10.2.5 Using the findings of the assessment
The assessment helped to highlight the range of potential environmental and social impacts, including
those that had been quantified and those that could only be identified qualitatively. The assessment
did not highlight any major effects that we had not already considered in developing the most
economic combinations of options, although it helped to identify where there are more minor effects
and how some of the potential negative impacts can be mitigated.
10.3 Habitats Regulations Assessment
10.3.1 The Process
As stated, we have undertaken a Habitats Regulations Assessment of this Plan, which is reported
separately.71
The Habitats Regulations Assessment was undertaken as an iterative process
alongside the development of the Plan, to help to ensure that the Final Plan will not have adverse
effects on any European Sites when implemented. The Habitats Regulations Assessment is
“appropriate” to the Plan, which means that it recognises that there are inherent uncertainties both
within strategic plans and within the Feasible options: that is, at this high level of planning it is only
possible to identify effects that may occur; it is not possible meaningfully to quantify or otherwise
assess the effects at this stage.
The Habitats Regulations Assessment has identified whether any feasible options would have
unacceptable effects on a European Site. This process informed the selection of the preferred
options. Further assessment was then undertaken on the preferred options to ensure that any likely
significant effect or adverse effects were identified and appropriate measures developed to ensure
that these effects would be avoided or reliably mitigated when the Final Plan is implemented.
The Habitats Regulations Assessment must also consider the potential impact on any European Site,
whether within our geographical boundary or not, and whether impacted individually by our Plan or in
combination with other Plans. In the case of our Plan, which operates at a strategic level, the main “in
combination” effects will be associated with other strategic plans and programmes, particularly those
involving water resources (for example, our Drought Plan).
10.3.2 Review of Feasible options
The Feasible options were reviewed for their possible effects on European Sites using a preliminary
screening method. This identified those European Sites that could potentially be affected by the
implementation or operation of each feasible option, given the characteristics of the Site, the means
by which it might be affected by the option, and the distance from the option to the Site.
This stage was primarily used to identify those options that would clearly have unacceptable effects
on a European site, which then informed the selection of the preferred options.
71 “Habitats Regulations Assessment of Revised Draft WRMP”: Entec UK Limited, March 2011.
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10.3.3 Assessment of Preferred options
Following from the screening of feasible options through both the Habitats Regulations Assessment
and Strategic Environmental Assessment process, the initial preferred options were re-screened and
assessed in greater detail for their likely impacts on European Sites.
Where potential effects were identified as “uncertain” (as is often the case when the examination is at
a comparatively strategic level) an assessment of likely significant effect was made and avoidance
measures or mitigation proposed to help to ensure that there would be no adverse effects. For some
options, any such effects are likely to be localised and can therefore be more appropriately assessed
at the more detailed planning stages. In this case, the assessment identified the risk of effects but
assumed that Habitats Regulations Assessment of lower level strategies or the individual options
themselves will be sufficiently rigorous to avoid significant or adverse effects.
Since the precise manner and timescale in which the various options could be implemented is
unknown, not all the possible effects can be assessed at the strategic level and some can only be
determined at a project level. This means that the Habitats Regulations Assessment must assume
that all normal controls will be applied (i.e. at a project-level Habitats Regulations Assessment) and
that likely significant effect can only be concluded where the level of development required is unlikely
to be accommodated, regardless of project-level mitigation.
For example, an option requiring construction work within a Special Area of Conservation may initially
appear certain to have likely significant effect; however, that option may involve simply refitting
existing operational structures, which can almost certainly be easily accommodated without likely
significant effect or adverse effects. The opposite is also true. This means that the strategic Habitats
Regulations Assessment must consider whether the likely level of development required for the option
can be accommodated and (if this is uncertain) whether there are other practicable options available
that will not have a likely significant effect.
10.3.4 Summary of Assessment
The Habitats Regulations Assessment concluded that most of the feasible and preferred options had
the potential for likely significant effect on at least one European Site; however, for most options it
was very clear that the potential effects were of a scale and type that could certainly be avoided at the
scheme level with standard and accepted measures.
There are two options where the available data strongly suggests that there will be no adverse
effects, but this cannot be concluded with certainty at the strategic level. These schemes are:
8108.1 Brecon-Portis: additional releases from Usk Reservoir; and
8206. 1 Pembrokeshire: re-instate Milton source for industrial use.
We believe that it is acceptable to include these schemes in the Plan for now on the basis that
Habitats Regulations Assessments and assessments at the scheme level can be expected to resolve
the uncertainties (since scheme-specific Habitats Regulations Assessment will be a legal requirement
before these schemes can be implemented), provided that potential alternatives with “no adverse
effects” are identified within the Plan. The Plan has therefore included these schemes as preferred
options, with the proviso that “alternative” options have been identified that could be employed should
the options in question prove to have adverse effects that are unavoidable. This process and the
“alternative” options are detailed fully in the Habitats Regulations Assessment report.
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10.3.5 Conclusion
Overall the Habitats Regulations Assessment has concluded that the Revised Draft Plan will not have
any significant adverse effects on any European Site (alone or in combination with other plans and
programmes) as a result of its implementation, since the preferred options:
either will have no significant or adverse effect as they stand; or
can be implemented using established and reliable best-practice mitigation/ avoidance
measures to ensure no significant or adverse effects; or
can be replaced by options that have no likely significant effect or adverse effects from the
feasible options list, should scheme-specific investigations demonstrate that adverse effects
are certain and cannot be avoided or mitigated.
All options will, in any case, be subject to project-level Habitats Regulations Assessment, as a matter
of legal requirement, which will provide an additional safeguard.
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Annex 1 – Resource Developments in AMP 4
This Annex outlines the changes we have made to how resources are provided during the AMP4
period 2005-2010
North Eryri - Ynys Mon
In AMP4 a £8M scheme was identified for North Eryri – Ynys Mon (NEYM). This substantial
engineering scheme enables improved utilisation of resources on Anglesey and retains resources on
the mainland for increased use during a drought. The scheme was modelled in detail using
WRAPSim and increased DO by 10 Ml/d. It was completed in March 2009.
Barmouth
We completed a scheme to link Lleyn - Harlech WRZ to Barmouth WRZ, during AMP4. This scheme
was in two parts:
we resolved the restrictions in capacity on the raw water main between Llyn Eiddew Mawr
and Rhiwgoch Water Treatment Works; and
we provided additional network distribution mains from Rhiwgoch into the Barmouth WRZ,
currently fed from Eithinfynydd Water Treatment Works. A statutory undertaking we gave to
the Drinking Water Inspectorate at Rhiwgoch Water Treatment Works reduced its design
capacity from the licenced volume of 2 Ml/d to the current maximum capacity of 1 Ml/d.
Towards the end of our 2005-2010 business plan period we embarked upon our 2010-2015 water
quality investment programme. Rhiwgoch Water Treatment Works was confirmed as a works that
would be upgraded as part of this programme, and this was completed by March 2010. As such, an
export from Lleyn - Harlech WRZ to Barmouth WRZ has now been incorporated within the supply
demand balance to resolve forecast future deficits within the Barmouth supply area. Within our 2010-
2015 water quality investment programme, these two zones will be merged and reported as a single
zone.
South Meirionydd and Blaenau Ffestiniog
We identified that benefits could be achieved in South Meirionydd (Afon Wnion to Llyn Cynwch) and
Blaenau Ffestiniog (Afon Gam to Llyn Morwynion) WRZs by carrying out changes that would allow us
to re-fill the reservoirs more effectively during the winter. These capital schemes were delivered
during 2008.
Ross-on-Wye
During 2005-2010 we completed mains refurbishment on the Hereford/Ross-on-Wye boundary. The
Ross-on-Wye WRZ is currently expanded during the summer period to supply part of the Hereford
WRZ due to water capacity constraints between Ridgehill and Aconbury Service Reservoirs (within
the Hereford WRZ).
Vowchurch
The 2008 Draft Plan identified a peak week supply deficit within the Vowchurch WRZ. To remove this
a new 4.5km, 180mm diameter main from Vowchurch was connected to the Aconbury Service
Reservoir in the Hereford WRZ in 2008.
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Whitbourne
We duplicated 3.3km of main between Hope under Dinmore and Bodenham, south of Leominster,
during 2006. We also undertook mains cleansing in the Leysters Service Reservoir zone, which the
Risbury pumping station can supply, to complete the work to allow transfers of water from the
Hereford area.
The exceptional rainfall and flooding during the summer of 2007, which resulted in the temporary loss
of Whitbourne Water Treatment Works, meant that this transfer could be used to restore customer
supplies following the bad weather. The new system was therefore used effectively and the supply
demand balance has been updated showing that the previous deficit in this zone has now been
resolved. We can transfer a maximum of 0.48 Ml/d in this way.
South East Wales Conjunctive Use System (SEWCUS)
In place of the weir at Prioress Mill on the River Usk we have invested in additional infrastructure to
enable full utilisation of the abstraction licence on the River Usk at Llantrisant by allowing the
abstracted water to be transferred to Llandegfedd reservoir if required. This gave a significant
increase in baseline Deployable Output of 48 Ml/d and secured supplies within SEWCUS.
During 2010, due to the extreme dry weather conditions, we made a number of improvements to
increase the resilience of the Pontsticill High Level area and the Rhondda and Cynon area. In the
Pontsticill High Level area we have made some network improvements to allow water from Blaen-y-
Cwm reservoir to be transferred to Nantybwch Water Treatment Works. In addition, transfer licences
are currently being sought to enable the transfer of untreated water from Blaen-y-cwm to Lower Carno
reservoir for subsequent re-abstraction and transfer to Shon Sheffrey reservoir. This will increase the
resilience of the system by connecting available storage to greater treatment capacity.
In the Rhondda and Cynon area, we laid a pipeline between Penderyn reservoir, which currently
feeds Hirwaun Water Treatment Works and Llyn Fawr reservoir. The pipeline can be operated in both
directions but requires pumps to be installed at Penderyn to transfer water to Llyn Fawr.
Pembrokeshire
The deficit in North Pembrokeshire was resolved during our 2005-2010 investment programme by the
extension of the network to aggregate two WRZs, North and South Pembrokeshire, thereby reducing
the number of zones to 24. The scheme involved:
the laying of a new 7.5km 500mm trunk main from Bolton Hill Service Reservoir to the North
Bridge in Haverfordwest; and
installing new pumps and refurbishing existing ones (at Corner Piece water pumping station),
so that water from either Preseli Water Treatment Works or Bolton Hill Water Treatment
Works can be pumped to Plumbstone Service Reservoir and onto St Davids.
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Annex 2 – Water Efficiency Activity
Cistern displacement devices
We offer free hippo bags to all our customers and promote this through the literature which
accompanies customer bills, as well as leaflets, podcasts, website material and general customer
engagement. The popularity of the Hippo Bag has continued to grow. In 2008-09 we provided
16,290 hippo bags to customers and in 2009-10 we provided 20,865, of which 3,403 were requested
by household customers and 612 requested by schools. The remainder were distributed at events
held by Welsh Water. In total we estimate that these displacement devices saved 0.29 Ml/d
(assuming a 2.8 litre saving per device, per flush).
Performance and attitudes towards these devices have been covered as part of the household water
audits that have recently been completed. These identified valuable savings where the devices had
been correctly installed. However, the installation rate at 59% was lower than the Ofwat quoted value
of 65%. In addition, a significant proportion had been fitted in dual flush, low flush and ultra low flush
cisterns and had either been subsequently removed or required repeat flushing.
In an attempt to address this problem improved information has been placed on our website and is
included with the material we send with the device. It remains to be seen if this helps customers
correctly to identify cisterns where it is appropriate to install Hippos. Using information from 2008
water audits, the estimated total daily saving from the Hippos distributed in 2008–09 was around 0.32
Ml/d. For total household demand this is a negligible saving in the context of the baseline demand
forecasts. However, as part of our options for water efficiency we have included a “Home Visit
Package” option. This includes the installation of Hippo bags as one of a suite of devices/ measures.
Household water audits
We have historically provided water audit visits to domestic customers to advise them on water
savings. These provided an excellent mechanism to educate customers on water efficiency issues
and the good practice use of water throughout the home; we also provided customers with low cost
devices to help them save water (including Hippo Bags). However, in 2008-09 we only completed 21
water audits in customers‟ homes (at the request of customers). Therefore, due to the small water
savings and the high staff cost rate involved, we no longer offer this service. Instead, we choose to
promote household water efficiency via our comprehensive self-audit pack that is promoted in
company literature and on our website, and which is available to customers on request. We consider
that this is a much more cost effective and less intrusive method of promoting water efficiency in the
home.
In 2008-09 we distributed 7,197 water audit packs to homes with a total estimated water saving of
0.85 Ml/d. This represents a fourfold increase on the previous year.
Household water audits continue to be included as intervention options as part of the “Home Visit
Package” option for all deficit zones
Commercial water audits
As with the household water audits, we no longer believe that offering on-site water audits is the most
effective method of promoting water efficiency in commercial premises. In 2008-09 we only
completed 11 such audits. We continue to advertise on our website and through customer
engagement the “using water wisely, DIY water audits for homes, business and schools” advice
leaflets; overall, we consider this to be the best method to promote water efficiency.
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We are carrying out pilot audits in a number of commercial/ non-household properties to develop
further our water audit experience and gain improved data on the realistic potential savings. This
approach has been concentrated initially in the North Eyri Ynys Mon WRZ and has since been
expanded into the Vowchurch WRZ (identified as a deficit zone in AMP4). In June 2009 we
commenced our water efficiency activities in Vowchurch sending letters and self–audit packs to all
non-domestic customers using over 2m3 of water per day. We had replies from 6 farms in the area
and undertook detailed on-site audits before making recommendations on improving their water
efficiency. All of these farms also had flow loggers installed to monitor their levels of consumption.
In 2009-10, we distributed water efficiency self-audits to all schools (Primary and Secondary) in the
Vowchurch WRZ followed up by a water audit at four of the schools. During 2010-11 we expect
further savings when water efficiency devices are fitted as recommended following the audits.
The audits are combined with a “Capacity Buy Back” option.72
Capacity Buy Back is included as an
intervention option for all deficit zones
Customer education/awareness
We have placed particular emphasis on our development of educational initiatives as these provide
future populations with an understanding of the issues and challenges associated with water use.
This is a core message in delivering the objectives of our Education Strategy “Living and Learning
with Water” which promotes the understanding of “the value of water and the vital role it plays in our
everyday lives”. Our educational initiatives are summarised below.
We have 4 Education Centres. These are located in the Elan Valley, Cilfynydd (near Pontypridd,
South Wales), Cog Moors (near Cardiff) and Alwen, where every one of the 14,000 visitors each year
receives water conservation messages. To date over 124,000 visitors have visited one of our 4
centres. To enhance the messages delivered at the centres, a water efficiency lesson has been
developed to inform pupils about the responsible use of water in both schools and in the home. This
lesson was developed by teachers and is linked to the National Curriculum to support sustainability
and Global Citizenship within schools.
We have developed a water efficiency pack to help schools use water more efficiently. The bilingual
pack called “Water is Cool – Respect it” is distributed to schools achieving Silver-level accreditation
through the Eco-Schools programme in Wales. To date almost 1,000 schools have received the
pack. The pack illustrates how important water is to each of us and helps children to understand its
value and the vital role it plays in our everyday lives. It contains interesting facts on how to use water
wisely and schools can use the pack as part of the Eco-Schools programme, or as part of an
independent water conservation project.
As one of the main partners in the re-launch of the Welsh Eco-Schools project we have contributed to
the water section of the Eco-schools Handbook. Schools have to complete and be assessed on 9
elements of the programme to become a Green Flag school. Water efficiency is one of these
elements. There are over 1,300 schools registered with Eco-Schools in Wales.
In March 2007 we launched our „Be Waterwise‟ campaign to encourage customers to „use what they
need, but not to waste it‟. The launch took place at Cilfynydd Education Centre with representatives
from Keep Wales Tidy, the Consumer Council for Water and from schools staff and pupils.
72
Capacity Buy Back provides an incentive through bill rebates. The scheme works by providing companies with a reimbursement on their
water bill based upon the water savings made through the implementation of a water efficiency measure. The bill rebate incentive saving is £0.40 per litre per day (£400,000 per Ml/d) up to a maximum of 50% of the cost of the water efficiency measure.
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We have supported the development of a number of educational resources. These include
“Waterworld Explorers” an interactive multimedia resource aimed at Key Stage II (7-11 year olds)
which has a module entitled “How is water used?” which demonstrates how water is used in the home
and garden and explains the measures that can be taken to reduce water usage. Waterworld
Explorers has been well-received by children and teachers alike and has been distributed to over
1,600 primary and secondary schools.
We continue to work in partnership with Techniquest, the science discovery centre based in Cardiff,
which receives over 200,000 visitors each year. We have developed an exciting display promoting
water efficiency. This uses jets of recycled water, which children can direct and fire, to show the
relationship between efficient and wasteful practices, for example, sprinkler and hosepipe use.
In partnership with the UK Education forum, representatives from 13 UK water companies have
contributed to the development of 2 water efficiency websites called The Water School and The Water
Family. The sites were developed by Crystal presentations and are aimed at encouraging pupils and
families to be more sustainable with water both in school and at home. Both sites were trialled by
teachers and linked to the National Curriculum. During the last academic year the following statistics
were recorded at each site:
Water in the School Website – 31,394 hits
The Water Family Website – 198,558 hits
To coincide with World Water Day we will be launching a new resource to promote water efficiency in
schools. The pack has been endorsed by Keep Wales Tidy and it will assist us in achieving high
accreditation via the UK Water Industry Research guidelines from Ofwat. Schools will be encouraged
to demonstrate water efficiency good practice in school and record their evidence. The evidence will
be collated by us to show behaviour changes within the school and in the home. The pack has also
been available on-line since April 2011. This will allow schools to register with Welsh Water and
receive quarterly newsletters updating them with water efficiency tips or any other key business
messages. This will again take our level of engagement from medium to high in the UK Water
Industry Research guidelines as we will ensure ongoing contact with the customer.
Our recently re-launched company website includes several “Living and Learning” webpages which
include a large amount of child friendly material on the business as well as water efficiency tips and
challenges for pupils, including an online water efficiency calculator and home audit. The site will
enhance children‟s awareness on sustainable water usage and includes an area where children can
complete a home audit and enter into a termly competition draw. The site enable adults and children
to feed back any comments on visits to the Education centres or on resources provided by Welsh
Water.
In 2010 Ofwat confirmed that 30% of “soft” targets could be counted against our new 1.3 Ml/d target.
To date approximately 90% of the target is being achieved through education. The focus on
achieving maximum results is our main driver over the next 4 years.
To trial our Outreach Programme on water efficiency we took part in a pilot at 30 schools in Blaenau
Gwent. The pilot involved a whole school assembly focusing on water efficiency followed by
workshops in the classroom and school audit. The pupils were then tasked with a toothbrush
challenge where they recorded how many times they turned the tap off when brushing their teeth,
thereby encouraging water savings and changing behaviours. The data was returned and recorded
for the June Return. Due to the success of this pilot we have continued delivering water efficiency
outreach in targeted areas working closely with Aqualogic, our preferred suppliers on water efficiency.
To date 1,073 pupils have taken part in the challenge. Ofwat are currently considering raising the
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maximum proportion of the water efficiency target that can be met by soft measures from 30% to
40%.
It is very hard to quantify the benefits of our range of promotional and educational activities.
However, the feedback received provides strong encouragement to continue our efforts in these
areas. Successful implementation of many water efficiency measures relies on customers
understanding the issues and responding in a socially responsible way. Because of this, the
continuing development of our promotional and educational activities is considered to be an essential
component of our water efficiency strategy.
Finally, we also promote a “Don’t crack up, wrap up” campaign which provides practical advice and
information that would avoid the inconvenience and expense that a frost damaged pipe can cause.
The advice was made available through publicised literature and a podcast published on our website.
Other water efficiency initiatives
Water efficiency has considerable prominence on our company website and is continually reviewed
and updated in accordance with our water efficiency activities.
We work closely with the National Trust to deliver water efficiency messages on organised theme
days and have developed a water efficient demonstration garden within one of the National Trust sites
that provides key awareness of water efficiency issues and solutions to visitors.
Finally, we have launched a “Four minute shower campaign” which was endorsed by the then
Environment and Sustainability Minister Jane Davidson AM and which encourages customers to limit
the time spent using the shower. The campaign has its own website and has already proved popular.
Metering
Our policy is to:
provide a free meter option scheme;
meter new households and non-households compulsorily; and
have a programme to meter existing unmeasured non-households, where practical.
Water butts/ composters/ trigger hoses
We offer subsidised water butts to all our customers and help promote the efficient use of water in the
garden through customer engagement (“message” areas of bills and leaflets provided to customers
during events and press releases) and advice on our website. In 2008-09 we installed 658 water
butts in households and distributed a total of 1,116. In 2009-10 we distributed 310 water butts, with
an estimated total saving of 0.0008 Ml/d.
Water butts and trigger hoses are included as intervention options (as part of the “Home Visit
Package” option for trigger hoses) for all deficit zones.
Retrofitting – toilets, showerheads
More complex retro-fitting of water saving devices such as taps, toilets and showers were not
identified as the optimal solutions to resolve deficits during our 2005-2010 programme and therefore
no savings are attributed within the baseline demand forecast.
However, retrofitting devices continues to be included as an option for all deficit zones as part of the
“Home Visit Package” and the “Non-Household Visit” option.
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Collaborative Research and Development
The best opportunity to encourage more water efficient fittings is at the time, for example, when
existing bathrooms are being refurbished or when new houses are being built. The additional cost of
fittings providing improved water efficiency will normally be negligible in comparison to the cost of the
installation.
We are currently working with housing developers on proposals to compare the water use of standard
houses adopting improved water efficiency standards, against similar phased non-water efficient
houses. The aim is not to create expensive eco-houses, but rather to investigate what can be
achieved at minimum additional cost to enhance the performance of standard homes.
Assumptions regarding the increasing penetration of dual and low-flush cisterns and more water
efficient washing machines and dishwashers are built into the forecasts of per capita consumption in
line with the obligations now required of developers in the Code for Sustainable Homes. Additionally,
assumptions are also included for the replacement of appliances as part of home improvements in
older properties.
Supply pipe repair/ replacement
Our experience is that proactive action to tackle leakage on customers‟ supply pipes is currently the
most cost effective area of water efficiency for investment. We have applied a consistent and
proactive policy on customer leakage since 2001. Under this policy we provide free leak detection
and repair service for the first leak on a customer‟s supply pipe. In 2008-09 there were 438 supply
pipes replaced free under this policy and 1,720 repaired.
The estimated average savings from our free supply pipe repair and replacement activities in 2008-09
is 1.31 Ml/d.
Our assessment of Supply Pipe Leakage follows the Bursts and Background Estimation (approach.
Work is still progressing nationally to improve the estimation of SPL; we continue to improve the
estimated volume of Supply Pipe Leakage, together with research into ways to identify leak run times.
The initial (pre-Maximum Likelihood Estimation) estimate of regional Supply Pipe Leakage for
unmeasured properties in 2008-09 was 20.1 l/prop/d. The equivalent figure for measured properties
was 16.4 l/prop/d. Also included in our demand forecasts is an estimated 1.18Ml/d of Supply Pipe
Leakage from void properties.
In 2008-09 the total operational expenditure on the customer Supply Pipe Leakage initiative was
£760k. This results in a unit cost of £1.59 per m3. Although this is similar to the national figure quoted
by Ofwat of £1.21 per m3
for water efficiency activities, we believe that this activity has a much higher
level of confidence in the level of savings achieved than other water efficiency activities.
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Annex 3 – Sites impacted by Habitats Review of Consents
Descriptions of the individual Special Areas of Conservation and our licences subject to the the
Environment Agency‟s Review of Consents process within them are detailed below and shown in
Figures A3.2, A3.3 and A3.4; an overview map showing the relationship between Welsh Water
abstractions and the European protected sites is shown in Figure A3.1
Figure A3.1 – Special Areas of Conservation and Sites of Special Scientific Interest in our supply area and the locations of Welsh Water’s abstractions
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South East Wales
River Wye Special Area of Conservation
The River Wye has been designated a Special Area of Conservation due to the presence of the
following features58
Atlantic Salmon, Allis Shad, Twaite Shad, Brook Lamprey, River Lamprey, Sea Lamprey, Bullhead,
Otter, Atlantic Stream Crayfish, Ranunculus, Transition Mires and Quaking Bogs.
Within the River Wye Special Area of Conservation we have thirteen abstraction licences that have
been subject to the Agency‟s review of consents process:
River Wye at Builth Wells – abstracted water is treated locally at Builth Water Treatment
Works and supplies the remainder of the Elan Builth WRZ.
River Wye at Llyswen – abstracted water is treated locally at Llyswen Water Treatment Works
and supplies the entirety of the Llyswen WRZ.
River Lugg at Byton - maintained as an emergency source for use locally within the Pilleth
WRZ.
Pilleth boreholes – abstract from the gravels of the River Lugg. The water is treated at the
nearby Pilleth Water Treatment Works and supplies the entirety of the Pilleth WRZ.
Dunfield boreholes – abstract water from the gravels of the River Arrow. The water is treated
at the nearby Dunfield Water Treatment Works and supplies the immediate localised area of
the Hereford WRZ.
Midsummer Meadow well - maintained as an emergency source for use locally within the
Hereford WRZ.
River Wye at Hereford – abstracted water is pumped a short distance to Broomy Hill Water
Treatment Works and supplies the majority of the Hereford WRZ.
Vowchurch boreholes - abstract water from the gravels of the River Dore. The water is treated
at the nearby Vowchurch Water Treatment Works and supplies the entirety of the Vowchurch
WRZ.
River Wye at Mayhill – located in Monmouth, water is pumped a short distance to Mayhill
Water Treatment Works and supplies the majority of the Monmouth WRZ.
Buckholt springs – water is treated at the adjacent Buckholt Water Treatment Works and
supplies the remainder of the Monmouth WRZ.
Alton Court borehole - maintained as an emergency source for use within our Ross-on-Wye
WRZ.
Rogerstone Grange borehole - abstracted water is treated locally at Rogerstone Water
Treatment Works and supplies locally within the south western area of the SEWCUS WRZ.
River Wye at Monmouth (“Wye Transfer”) - located approximately 500m upstream of the
Mayhill intake, water is transferred out of the catchment across to Court Farm Water
Treatment Works and is used to supply parts of the SEWCUS WRZ.
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58 Site Issue Briefing (Countryside Council for Wales, 2002)
The Elan valley reservoirs have also been subject to the consents review process as they are
intrinsically linked to the operation of our Monmouth abstraction licence. Elan‟s two main functions
are to supply water to Birmingham via the Frankley Reservoirs (to Severn Trent Water) and to
regulate the River Wye to support abstraction in its lower reaches. There is a small direct supply to
Elan Water Treatment Works which supplies the majority of the Elan Builth WRZ.
Figure A3.2 - Welsh Water’s abstractions in South East Wales subject to the Review of Consents process
River Usk Special Area of Conservation
The River Usk has been designated as an Special Area of Conservation due to the presence of the
following features58
:
Atlantic Salmon, Allis Shad, Twaite Shad, Brook Lamprey, River Lamprey, Sea Lamprey, Bullhead,
Otter, Ranunculus.
Within the River Usk Special Area of Conservation we have four abstraction licences that have been
subject to the consents review process:
Brecon boreholes – this licence abstracts water from the gravels of the River Usk. The water
is treated at the nearby Brecon Water Treatment Works and supplies the majority of the
Brecon-Portis WRZ demand.
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River Usk at Brecon – this river intake is licensed for the same quantity as the boreholes
(aggregated licence). Operationally this abstraction point is not frequently used.
River Usk at Rhadyr (Prioress Mill) - water is abstracted and pumped to Llandegfedd reservoir
before being treated at Sluvad Water Treatment Works. This water is then supplied in the
SEWCUS WRZ.
River Usk at Llantrisant – the abstracted water can either be pumped to Llandegfedd reservoir
or direct to Court Farm Water Treatment Works; via both routes the water is treated and
supplied in the SEWCUS WRZ.
The operation of Usk reservoir has also been reviewed by the Environment Agency under the
consents review process due to the reservoir‟s ability to be used to regulate the River Usk.
Currently its two main functions are a small direct supply to Portis Water Treatment Works
which supplies a localised area of the Brecon-Portis WRZ and a larger export of water to
Bryngwyn Water Treatment Works, within the Tywi CUS WRZ, for localised supply within the
area.
South West Wales
Cleddau Rivers Special Area of Conservation
The Cleddau Rivers have been designated as an Special Area of Conservation due to the presence
of the following features58
Otter, Bullhead, River Lamprey, Brook Lamprey, Sea Lamprey, Ranunculus, Alluvial forests with
Alnus glutinosa and Fraxinus excelsior, Active Raised Bogs.
Within the Cleddau Rivers Special Area of Conservation we have four abstraction licences that have
been reviewed by the Agency:
Eastern Cleddau at Pont Hywel - abstracted water is transferred westwards to Preseli
reservoir (which feeds Preseli Water Treatment Works) which supplies the north of the
Pembrokeshire WRZ.
Eastern Cleddau at Canaston – abstracted water is transferred south-west to Bolton Hill
Water Treatment Works for treatment and supply but is also delivered to the large industrial
users in the Pembrokeshire WRZ.
Western Cleddau at Crowhill - abstracted water is transferred to Bolton Hill Water Treatment
Works for treatment and supply in the south of the Pembrokeshire WRZ.
Afon Syfynwy – a non-consumptive abstraction which is used to supply a fish farm – this is
currently not operational.
River Tywi Special Area of Conservation
The River Tywi has been designated as an Special Area of Conservation due to the presence of the
following features58
:
Allis Shad, Twaite Shad, Brook Lamprey, River Lamprey, Sea Lamprey, Bullhead, Otter.
Within the River Tywi Special Area of Conservation we have two abstraction licences plus the
operation of Llyn Brianne reservoir that have been reviewed by the Agency:
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River Tywi at Manorafan - the intake is generally not used due to its high operational costs but
when it is, the abstracted water is transferred to Bryngwyn Water Treatment Works for
treatment and is supplied to the central section of the Tywi Gower WRZ.
River Tywi at Nantgaredig - abstracted water is transferred eastwards to the Lliw reservoirs
which feed Felindre Water Treatment Works. The treated water supplies the conurbations of
Swansea, Neath and Llanelli and further east into Bridgend, Vale of Glamorgan and Llynfi
Valleys.
Llyn Brianne reservoir – its main function is to release water to support abstraction at
Nantgaredig.
River Teifi Special Area of Conservation
The River Teifi has been designated as a Special Area of Conservation due to the presence of the
following features:
Atlantic Salmon, Brook Lamprey, River Lamprey, Sea Lamprey, Bullhead, Otter, Luronium, Litorella,
Ranunculus.
Within the River Teifi Special Area of Conservation we have one abstraction licence that has been
subject to this consents review process:
River Teifi at Llechryd - abstracted water is transferred a short distance to Llechryd Water Treatment Works from where it is delivered to the south and west of the Mid & South Ceredigion WRZ.
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Figure A3.3 - Welsh Water’s abstractions in South West Wales subject to the Review of Consents process
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North Wales
Afon Gwyrfai a Llyn Cwellyn Special Area of Conservation
The Afon Gwyrfai and Llyn Cwellyn have been designated as a Special Area of Conservation due to
the presence of the following features:
Atlantic Salmon, Otter, Luronium, Litorella, Ranunculus.
Within the Afon Gwyrfai and Llyn Cwellyn Special Area of Conservation we have two abstraction
licences that have been reviewed by the Environment Agency as part of its review of consents
process:
River Gwyrfai at Nant Mills – this is located approximately 1km downstream of the outlet from
Llyn Cwellyn. This site is no longer operationally used.
Direct abstraction from Llyn Cwellyn where the water is transferred 2km downstream to
Cwellyn Water Treatment Works which supplies the local area in and around Caernarfon
within the North Eyri Ynys Mon WRZ.
Migneint-Arenig-Dduallt Special Area of Conservation
The Migneint-Arenig-Dduallt has been designated as a Special Area of Conservation due to the
presence of the following features:
Blanket Bog, European Dry Heaths, Northern Atlantic Wet Heaths, Natural Dystrophic Lakes
and Ponds, Lakes (Oligotrophic to mesotrophic) standing waters, Old sessile oak woods.
Within the Migneint-Arenig-Dduallt Special Area of Conservation we have one abstraction licence that
has been subject to the Review of Consents process:
Direct abstraction from Llyn Morwynion where the water is transferred 1km north-west to
Garreglwyd Water Treatment Works; the only source of water for the Blaenau Ffestiniog
WRZ.
Rhinog Special Area of Conservation
Rhinog has been designated as a Special Area of Conservation due to the presence of the following
features:
Old sessile oak woods , Blanket Bog, European Dry Heaths, Alpine and subalpine heaths ,
Depressions on peat substrates, Northern Atlantic Wet Heaths, Lakes (Oligotrophic to
mesotrophic) standing waters, Floating water-plantain (Luronium).
Within the Rhinog Special Area of Conservation we have one abstraction licence that has been
reviewed by the Environment Agency:
Direct abstraction from Llyn Eiddew Mawr - abstracted water is transferred 6km south-west to
Rhiwgoch Water Treatment Works which supplies the southern section of the Lleyn Harlech
WRZ in and around Harlech.
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Llwyn Special Area of Conservation
Llwyn has been designated as a Special Area of Conservation due to the presence of the following
features:
Alluvial forests with Alnus glutinosa and Fraxinus excelsior.
Within the Llwyn Special Area of Conservation we have one abstraction licence that has been subject
to the consents review process:
Llwyn Isaf boreholes – water is abstracted from the Clwyd sandstone aquifer and is used to
augment flows in the River Clwyd. During a drought, the abstracted water is treated locally
and put into direct supply.
Figure A3.4 - Welsh Water’s abstractions in North Wales subject to the Review of Consents process
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Annex 4 – Option Ranking
Figure A4.1 – Ranking of Feasible Options, Pembrokeshire WRZ, by average incremental social cost (p/m
3)
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Figure A4.2 - Ranking of Feasible options, Brecon - Portis WRZ, by average incremental social cost (p/m3)
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Figure A4.3 - Ranking of Feasible options, South East Wales Conjunctive Use System (SEWCUS) WRZ, by average incremental social cost (p/m3)
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Annex 5 Glossary of Terms
Abstraction The removal of water from any source, either permanently or temporarily.
Abstraction licence The authorisation granted by the Environment Agency to allow the removal of water from a source.
Annual average The total demand in a year, divided by the number of days in the year.
Available headroom The difference (in Ml/d or percent) between water available for use (including imported water) and demand at any given point in time.
Average incremental social costs
The ratio of present social costs over present net value of additional water delivered or reduced demand
Consumption monitor A sample of properties whose consumption is monitored in order to provide information on the consumption and behaviour of properties served by a company.
Demand management
The implementation of policies or measures which serve to control or influence the consumption or waste of water (this definition can be applied at any point along the chain of supply).
Deployable output
The output of a commissioned source or group of sources or of bulk supply as constrained by: • environment • Licence, if applicable • Pumping plant and/or well/aquifer properties • raw water mains and/or aquifers • treatment • water quality
Distribution input The amount of water entering the distribution system at the point of production.
Distribution losses Made up of losses on trunk mains, service reservoirs, distribution mains and communication pipes. Distribution losses are distribution input less water taken.
Drought order
An authorisation granted by the Secretary of State under drought conditions, which imposes restrictions upon the use of water and/or allows for abstraction/impoundment outside the schedule of existing licences on a temporary basis.
Drought permit An authorisation granted by the Environment Agency under drought conditions, which allows for abstraction/impoundment outside the schedule of existing licences on a temporary basis.
Economic level of leakage (ELL)
The level of leakage at which it would cost more to make further reductions than to produce the water from another source
Final planning scenario
The scenario of water available for use and final planning demand forecast which constitute the company‟s best estimate for planning purposes, and which is consistent with information provided to Ofwat for the Periodic Review.
Habitats Regulations Assessment (HRA)
An assessment, required under the EU Habitats and Species Directive, of the potential effects of a proposed plan, programme or project on one or more Natura 2000 sites.
Level of Service The frequency with which a hosepipe ban or a Drought Order/ Permit would be expected to be required in order to maintain water supplies
Meter optants Properties in which a meter is voluntarily installed at the request of its occupants.
Meter programme Properties, which are to be metered according to current company metering policy.
Net Present Value The difference between the discounted sum of all of the benefits arising from a project and the discounted sum of all the costs arising from the project.
Non-households Properties receiving potable supplies that are not occupied as domestic premises, for example, factories, offices and commercial premises.
Outage A temporary loss of deployable output.
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Point of consumption The point where the supply pipe rises above ground level within the property, usually the inside stopcock or an internal meter.
Point of delivery
The point at which water is transferred from mains or pipes, which are vested in the water supplier into, pipes which are the responsibility of the customer. In practice this is usually the outside stopcock, boundary box or external meter.
Point of production The point where treated water enters the distribution system.
Review of Consents The mechanism by which the Environment Agency undertake their review of all the existing and proposed permissions that could impact upon EU designated sites
Risk A measure of the probability and magnitude of an event and the consequences of its occurrence.
Source A named input to a resource zone. A multiple well/spring source is a named place where water is abstracted from more than one operational well/spring.
Strategic Environmental Assessment (SEA)
A process of assessing the environmental opportunities and restrictions of a project, and identifying and managing its implications.
Supply-demand balance
The difference between water available for use (including imported water) and demand at any given point in time (c.f. available headroom).
Supply pipe losses The sum of underground supply pipe losses and above ground supply pipe losses.
Sustainability reduction
Reductions in deployable output required by the Environment Agency to meet statutory and/or environmental requirements.
Target headroom The threshold of minimum acceptable headroom, which would trigger the need for water management options to increase water available for use or decrease demand.
Total leakage The sum of distribution losses arid underground supply pipe losses .
Treatment work operational use
Treatment process water i.e. net loss, which excludes water returned to source water .
Underground supply pipe losses
Losses between the point of delivery and the point of consumption.
Unrestricted demand The demand for water when there are no restrictions in place .
Water available for use (WAFU)
The value calculated by deducting allowable outages and planning allowances from deployable output in a resource zone.
Water Resource zone (WRZ)
The largest possible zone in which all resources, including external transfers, can be shared and hence the zone in which all customers experience the same risk failure from a resource shortfall of supply
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