demand management plan - bellingen shire · water demand trend tracking and climate correction...

OCTOBER 2012

Bell ingen Shire CouncilDemand Management Plan

Bellingen Shire Council

Job Number A408

A408 Bellingen Shire Demand Management Plan Rev3 HydroScience Consulting October 2012 Page 1

Demand Management Plan

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29 October 2012

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Executive Summary

This Demand Management Plan reviews Bellingen Shire Council’s (BSC) existing

demand management measures and recommends further actions that Council can

implement to achieve best-practice demand management.

The water demand analyses include climate corrected historical water production and

demand forecast analyses for the Lower Bellinger and Dorrigo water supply schemes.

The analyses for the Lower Bellinger water supply scheme were done using the

following models developed by NSW Office of Water:

Water Demand Trend Tracking and Climate Correction Model;

Demand Management Decision Support System (known as the DSS).

The outcomes of these analyses include:

Annual demand forecasts;

Peak Day Demand forecasts;

Unaccounted for Water Analyses;

Potential water demand management measures suitable to BSC.

A rainwater tank assessment was also undertaken to identify the benefits of using

rainwater to replace potable water. This assessment was done using the Rainwater

Tank Model developed by NSW Office of Water. It was performed for the Lower

Bellinger scheme water supply area. However the benefits identified from using

rainwater tanks could be applied to other localities within the Shire. The outcome of this

assessment is provided in Appendix C.

BSC has the following existing demand management measures in place:

Community Education;

System Water Loss Management.

The DSS model prepared for Lower Bellinger water supply scheme prioritised demand

management options based on benefit cost ratios. The outcomes of the model

indicate that the preferred potential demand management measures for BSC were, in

order of priority:

Conservation Pricing for Residential Users

Residential Washing Machine Rebate

National Mandatory Water Efficiency Labelling Scheme (WELS)


Rainwater Tanks for all new Residential Development BASIX - Fixture Efficiency

with Rainwater Use

Residential Shower Retrofit

The existing and potential demand management measures have been analysed and

their benefits are provided in section 5 of the report. Section 5 of this report contains a

proposed implementation plan for the potential water demand management

measures identified for BSC.

The main aims of implementing the demand management measures recommended to

BSC are to:

Ensure water availability;

Project water demand to determine the need of water demand management

actions;

Satisfy the Best-Practice Management Guidelines requirement;

Reduce capital works (new reservoirs and sewerage treatment plant) costs.

It is expected that BSC will continue the implementation of the existing demand

management measures and where practical implement the potential water demand

management measures identified. If BSC decides to implement demand

management, it is recommended that an assessment process to monitor and evaluate

implementation be developed.

It is expected that the implementation of potential water demand management

actions will be considered by Council as opportunities arise and specifically as part of

its Annual Management Plan.


Contents

Contents ...........................................................................................................................4

1 Introduction.......................................................................................................6

1.1 Project Background .......................................................................................................... 6

1.2 Context ............................................................................................................................... 6

2 Demand Monitoring ......................................................................................8

3 Demand Forecasting .................................................................................. 10

3.1 Approach ......................................................................................................................... 10

3.2 Demand Trend Tracking and Climate Correction Model ........................................ 10

3.3 Demand Side Management Decision Support System (DSS) Model ..................... 11

3.4 Demand Forecast Based on Growth Projections ...................................................... 12

3.5 Dorrigo Water Supply Scheme ...................................................................................... 12 3.5.1 Scheme Overview ................................................................................................................... 12 3.5.2 Annual Demand Analysis ....................................................................................................... 13 3.5.3 Per Capita Demand Analysis ................................................................................................ 14 3.5.4 Peak Day Demand Analysis................................................................................................... 15 3.5.5 Demand Forecast for Each Customer Category ............................................................... 16

3.6 Lower Bellinger Water Supply Scheme ........................................................................ 17 3.6.1 Scheme Overview ................................................................................................................... 17 3.6.2 Annual Demand Analysis ....................................................................................................... 19 3.6.3 Per Capita Demand Analysis ................................................................................................ 20 3.6.4 Peak Day Demand Analysis................................................................................................... 20 3.6.5 Demand Forecast for Each Customer Category ............................................................... 23

4 Demand Management Planning ........................................................... 25

4.1 Water Demand Management Drivers ......................................................................... 25 4.1.1 Impact of Climate Change ................................................................................................... 25 4.1.2 Non-revenue Water ................................................................................................................ 26

4.2 Demand Management Measures in Place ................................................................ 28 4.2.1 Community Education ........................................................................................................... 28 4.2.2 System Water Loss Management ......................................................................................... 29

4.3 Demand Management Scenarios ............................................................................... 29

4.4 Potential Demand Management Measures .............................................................. 31 4.4.1 Introduction .............................................................................................................................. 31 4.4.2 Conservation Pricing for Residential Users ........................................................................... 32 4.4.3 Residential Washing Machine Rebate Program ................................................................ 33 4.4.4 National Mandatory Water Efficiency Labelling Scheme (WELS) program ................... 33


4.4.5 Residential Shower Retrofit ..................................................................................................... 34 4.4.6 BASIX - Fixture Efficiency with Rainwater Use ...................................................................... 34

4.5 Summary and Comparison ........................................................................................... 36

4.6 30 year projected Water Savings Outcomes ............................................................. 37 4.6.1 Lower Bellinger Water Supply Area ...................................................................................... 37 4.6.2 Dorrigo Water Supply Area .................................................................................................... 39

5 Proposed Implementation Plan ............................................................ 41

5.1 Overview ........................................................................................................................... 41

5.2 5 years Demand Management Implementation Outcomes .................................. 41

6 Reference ......................................................................................................... 43

Appendix A ................................................................................................................... 44

Appendix B ................................................................................................................... 54

Appendix C ................................................................................................................... 66


1 Introduction

1.1 Project Background

All NSW Local Water Utilities (LWUs) are encouraged to improve their water supply

businesses in accordance with the Guidelines for Best-Practice Management of Water

Supply and Sewerage (2007) prepared by NSW Office of Water.

By developing this Demand Management Plan Bellingen Shire Council (BSC) aims to

ensure a safe and secure potable water supply in the future and to comply with the

Best-Practice guidelines.

For this study, demand analyses were performed for both the Lower Bellinger water

supply scheme (LBWSS) and the Dorrigo water supply scheme (DWSS). The demand

analyses for LBWSS included climate correction of historical demand and demand

forecasting using the Water Demand Trend Tracking and Climate Correction model

and the DSS model, both developed by NSW Office of Water. The main outcomes of

these models are presented in section 3.5 and details of the analyses are provided in

Appendix A and Appendix B.

1.2 Context

This Demand Management Plan was developed to ensure that water use in the BSC

service areas is efficient and appropriate.

According to the NSW Office of Water Best Practice Management Guidelines (2007)

water demand management and demand management plan must cover four

elements:

1. Demand monitoring

2. Demand forecasting

3. Demand management planning

4. Implementation

Element 1: demand monitoring is done by Council. BSC best-practice management

compliance status in regards to demand monitoring is provided in Section 2.

Element 2: this was completed during the preparation of this report. The demand

management plan provides a description of the existing Lower Bellinger and Dorrigo

water supply schemes and their historical and expected demand. The relevant

technical information about demand forecasting is provided in Appendix A and

Appendix B.


Element 3: this is the main outcome of this report. It includes potential demand

management measures for BSC water supply schemes. BSC’s current water demand

management measures and potential measures were identified including their water

saving and financial benefits.

Element 4: BSC has already implemented some water demand management

measures. Other potential demand management measures are provided for Council’s

consideration and future implementation.

A demand management implementation plan including five years estimated costs is

detailed for Council’s consideration.


2 Demand Monitoring

Best-practice water conservation and demand management are essential for efficient

management of a Local Water Utility water supply business and for efficient use for

water resources. Table 1 below presents Bellingen Shire Council’s demand monitoring

status.

Table 1: Water Demand Management Compliance with Best-Practice Requirements

Requirements Compliance Comments

Demand Monitoring

Bulk water production metered and

recorded on a daily basis

Yes

All free standing and multi-unit residential

developments (both strata and non-strata)

approved after 1 July 2004 must be

separately metered.

Yes

Customer water consumption billed at

least three times a year (and preferably

quarterly).

Yes Council bills water supply customers four

times a year: May, August, November and

February.

Customers classified in accordance with

the categories defined in the latest NSW

Water Supply and Sewerage Performance

Monitoring Report and consumptions

reported annually.

No Council’s customer categories are

breakdown into residential and non-

residential only. Consumption is recorded

in Council’s billing data base - Water and

Sewer Knowledge Centre.

The NSW Office of Water suggests that each LWU should review its demand

management measures every 2 years to ensure that it has an appropriate balance

between demand and supply-side investment.

The customer types are classified in accordance to the categories defined in the NSW

Water Supply and Sewerage Performance Monitoring Report and are detailed in Table

2 (source: Water Conservation & Demand Management Check List, NSW Office of

Water, Best-Practice Management of Water -Supply and Sewerage Guidelines, Aug

2007).


Table 2: Water Demand Customer Types for Performance Indicator

Customer Type Descriptions

Total Revenue Water (Potable)

Residential Domestic (in-house and ex-house) potable water consumption

Commercial Offices, shops, clubs, hotels, motels, caravan parks potable

consumption.

Industrial Factories, mills, poultry, feed lots, sale yards, abattoirs, mining

potable consumption

Rural Farms or hobby farms outside urban zoned land, includes stock

and domestic uses, market gardens, agricultural irrigation potable

consumption

Institutional Hospitals, schools, college etc. potable consumption.

Public Parks & Gardens Watering of public parks, gardens, ovals etc. using potable water

Recommendation: BSC to modify consumption data recording system in order to

identify consumption based on customer categories of residential, commercial,

industrial, rural, and institutional and Public Parks & Gardens as detailed in Table 2.


3 Demand Forecasting

3.1 Approach

As a Local Water Utility, Bellingen Shire Council is responsible for the water supply

functions within the Bellingen Local Government Area. Council operates two water

supply schemes:

Dorrigo Water Supply Scheme (DWSS) and

Lower Bellinger Water Supply Scheme (LBWSS).

This section provides an overview of the demand analyses methods used to assess

these schemes and the result of these demand analyses for each of these schemes.

Water supply schemes with populations larger than 1,500 people are required to have

climate corrected historical demand analyses and forecasting demand analyses using

the models developed by the NSW Office of Water:

Water Demand Trend Tracking and Climate Correction Model: which tracks

past trends in water production on a climate corrected basis and provides

expected production figures based on the historical climate corrections.

Demand Management Decision Support System (known as the DSS): which

forecasts demand based on the climate corrected demand figures and

provides a preliminary evaluation of demand management measures.

The permanent population served by the LBWSS in 2009 was 8,334 excluding visitors

(BSC IWCM Strategy, Dec 2011). Water demand from the Lower Bellinger water supply

scheme has been analysed using the models developed by NSW Office of Water.

Major outcomes of this analysis in provided in section 3.6. Detailed analyses is provided

in Appendices A and B.

Dorrigo Township’s permanent population in 2009 was 1,223 people excluding visitors

(BSC IWCM Strategy, Dec 2011). DWSS demand forecasts were analysed applying the

growth rate to the daily water production operation records. This analysis is provided in

section 3.5.

3.2 Demand Trend Tracking and Climate Correction Model

This model is used to track past trends in water production on a climate corrected basis

and it estimates climate-corrected demand, based on per-capita demand and

population growth. By climate correcting the demand a more realistic estimate of the

water supplies normal demand can be ascertained.


Climate has a significant impact on water demands. In examining long-term past

demand patterns it is essential to understand the effect of climate on water demand.

A Climate Correction Model is used to track past trends in water production on a

climate corrected basis. The model considers that the climatic conditions that affect

demand are temperature, rainfall and evaporation.

The model’s approach involves two main phases:

Model calibration and tracking of production against a defined baseline

period;

Trend tracking, where the departures of the observed demands from those

predicted by the baseline model are analysed.

The outcome is a climate-corrected demand forecast based on per-capita demand

and population growth. By climate correcting the demand a more realistic estimate of

the water supplies normal demand can be ascertained. Thereby it is not overreacting

to very dry or very wet years.

The approach and methodology used to run this model is outlined in NSW Office of

Water’s Water Demand Trend Tracking and Climate Correction (Version 10) Manual,

May 2002 (Reformatted June 2006).. A summary of the methodology and details of the

model outcomes are shown in Appendix A.

3.3 Demand Side Management Decision Support System (DSS) Model

The DSS model is a tool designed by the NSW Office of Water to develop demand

forecasts and preliminary evaluations of demand management measures.

This model uses the climate corrected historical demand data to develop demand

forecasts and preliminary evaluation of demand management measures as required

by the Best-Practice Management planning framework. The modelling includes the

development of demand management scenarios which test the impact of

implementing additional demand management measures on water demand.

Typically, the modelling includes development of the baseline forecast and four

demand management scenarios. The baseline forecast is the baseline scenario

calculated by the model assuming no change in Council’s existing demand

management approach. The four scenarios, determined by Council, test the impact of

implementing additional demand management measures.

The outcomes of the Water Demand Trend Tracking and Climate Correction Model are

used in the DSS model to forecast two main parameters:

Average annual demand: This is used to estimate the adequacy of the water

sources.


Peak day demand: This is used to assess the required capacity of major system

assets such as treatment plants and service reservoirs.

The outcome of this model includes a series of graphs forecasting 30 year demand for

the various demand management scenarios and an estimation of the effectiveness of

the demand management initiatives.

The limitations of the model and the data available (e.g. uncertainty of growth rate

and potential errors in the historical data recorded) may have resulted in inaccurate

demand projections. This needs to be taken into consideration when analysing the

results of the model. The approach and methodology used to run this model are

detailed in the Demand Side Management Decision Support System – Simplified

(Version S1.1) Manual, July 2006, prepared by NSW Office of Water. A summary of the

methodology and data used in the model is provided in Appendix B.

3.4 Demand Forecast Based on Growth Projections

Council staff has advised that a shire wide population growth rate of 0.5% is should be

assumed for the purpose of the demand analyses. This growth rate has also been

applied for the calculation of demand management measures implementation costs.

The outcomes of these demand projection analyses are provided in the following

sections.

3.5 Dorrigo Water Supply Scheme

3.5.1 Scheme Overview

Dorrigo Water Supply Scheme (DWSS) serves the town of Dorrigo and the surrounding

rural residential, farming and commercial developments.

The DWSS sources water primarily from the Bielsdown River. However, when the River

flow is less than 20 ML/d at DNR Gauging Station 204017, Council is required to cease

extraction from the River. Instead, water is pumped from an on-stream storage on

Rocky Creek.

Raw water is transferred to the Dorrigo Bellingen Water Treatment Plan (WTP) which has

a capacity of 2.74 ML/d. Water undergoes pH correction, flocculation and sand

filtration processes before delivering to a clear water tank for storage. Treated water is

dosed with chlorine and lime before water is pumped to one of the two Dorrigo Town

reservoirs and gravitates to customers.

A historical water production analysis and a demand forecast analysis were

undertaken with the data provided as shown in Table 3


Table 3: Dorrigo Water Supply Scheme Demand Analyses Input Data

Data Required Data Used Comments/Source

Population DWSS Permanent Population excluding visitors:

1,383 in 1991

1,238 in 1996

1,166 in 2001

1,225 in 2006

1,223 in 2009

(Source: Table 2.3 Historical

Populations Connected to

Water Supply System, BSC

IWCM Strategy, Public Works,

Dec 2011)

Growth rate 0.5% per annum BSC staff

Daily Water

Production

8 years (2003 – 2011) of daily water production Data was scanned for errors

and plotted to show the

trend in water production

(see Figure 1). Source: Data

log from Dorrigo water

consumption data from BSC

(May 1994 – June 2011)

3.5.2 Annual Demand Analysis

Figure 1 shows the historical annual water production and projected water demand in

Dorrigo. The starting point for Dorrigo annual demand forecast analysis has been

assumed to be the average annual water production over the past 5 years (from 2007

to 2011).

The pricing structure was changed in 2008 to a two-tier water pricing. The average of

the 3 years annual consumption after that would be expected to be included as the

starting point. However, 2009 was unusually wet and was considered to not be

representative of normal consumption. For this reason, 5 years data has been used in

this analysis.

The annual water demand projections were estimated using Bellingen Shire’s

population growth rate of 0.5%.

The analysis shows that DWSS annual water production is lower than the water

extraction licence entitlement and that the current extraction entitlement will be

sufficient to supply the town’s long term annual demand.


Licenced Annual Extraction 300 ML/y

100.0

120.0

140.0

160.0

180.0

200.0

220.0

240.0

260.0

280.0

300.0

320.0An

nual

Dem

and

(ML/

y)Dorrigo Annual Demand Forecast

Historical Data Demand Projections

Figure 1: Dorrigo Annual Demand Forecast

3.5.3 Per Capita Demand Analysis

DWSS’s per capita demand forecast is shown in Figure 2. The per capita demand is

assumed to be steady for the 30 years planning horizon. The starting point of the per

capita demand forecast (413 L/d) is assumed by calculating the average of the past 5

years (from 2007 to 2011) of historical per capita production.

The data used in this analysis is sourced from the DWSS water production figures which

includes residential, commercial customers and unaccounted for water. Based on the

water consumption by customer type data from Council’s data base, the residential

water consumption in Dorrigo represented about 49% of the total water consumption in

2009. The estimated residential water consumption per capita is approximately 230 L/d

in 2012, which is lower than state wide median consumption of 250L/p/d (estimated

based on 2010/11 NSW Office of Water TBL Performance Indicators).


200.0

250.0

300.0

350.0

400.0

450.0

500.0

550.0

600.0To

tal P

er C

apita

Wat

er D

eman

d (L

/d)

Dorrigo Per Capita Demand Analysis

Historical Demand Projections Actual Per capita demand (residential)

Figure 2: Dorrigo per Capita Demand Forecast

3.5.4 Peak Day Demand Analysis

An analysis of average daily demand has been undertaken to assess the adequacy of

DWSS’s infrastructure capacity to supply peak day demand (PDD) both current and in

30 years’ time. Dorrigo peak day demand has been calculated by applying the 99.5

percentile from the past 3 years daily production data as the starting point of the PDD

forecast.

The water access licence for Dorrigo water supply has no time or rate limits for such

extraction from the water source, there is therefore no restriction on DWSS’s headwork’s

peak day supply.

It is generally considered good practice that reservoirs have a capacity to supply no

less than 1 day of PDD. Dorrigo Town Reservoirs 1 and 2 capacities are 1.6 ML and 1.1

ML, respectively and the Dorrigo WTP’s capacity is 2.7 ML/d. These capacities are

above Dorrigo estimated long term PDD of approximately 1 ML/d.

The PDD analysis indicates that the current capacity of either one of the reservoirs and

of the WTP is sufficient to supply DWSS’s estimated peak day demand in 30 years as

shown in Figure 3.


Reservoir 1 Capacity

Dorrigo WTP Capacity

Reservoir 2 Capacity

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0P

eak

Day

Dem

and

(ML/

d)

Dorrigo Annual Average & Peak Day Demand

Peak Day Demand Reservoir 1 Capacity Dorrigo WTP CapacityHistorical Data Reservoir 2 Capacity

Figure 3: Dorrigo Peak Day Demand Forecast

3.5.5 Demand Forecast for Each Customer Category

BSC’s water consumption records are grouped into water sales for residential and non-

residential only. Demand forecast analysis for each customer category was performed

by applying data from BSC’s IWCM Strategy (Table 4) and an assumption of 1%

population growth per annum in the next 30 years. However it is noted that the water

supply customer categories in the IWCM were grouped on a basis different to the Best-

Practice Guidelines.

Table 4: Dorrigo Water Supply Historical Customer Consumption

Note: 1: Customer consumption data available until March 2009 2. Restricted Years 3. WTP production data available until 11/4/09 (Source: Bellingen Shire Council IWCM Strategy, Public Works NSW Water Solutions, Dec 2011)


In Figure 4, data from BSC’s IWCM Strategy were used to show the demand forecast by

customer type for DWSS. It is assumed that the current ratios between each customer

type’s water consumption will remain the same over the 30 year planning horizon.

DWSS Demand Forecast by Customer Type

0

10

20

30

40

50

60

70

80

90

100

110

2001

2003

2005

2007

2009

2011

2013

2015

2017

2019

2021

2023

2025

2027

2029

2031

2033

2035

2037

2039

2041

Cus

tom

er C

onsu

mpt

ion

(ML/

y)

Residential

Commercial

Farms

Tourism

RuralResidential

Council

Institution

Industrial

Figure 4: Dorrigo Scheme Demand Forecast by Customer Type

3.6 Lower Bellinger Water Supply Scheme

3.6.1 Scheme Overview

Since 1960 the Lower Bellinger Water Supply Scheme (LBWSS) supplies water to

Bellingen town, the coastal villages of Raleigh, Repton, Mylestom and the town of

Urunga.

The main sources of water are an infiltration well and three bores located upstream of

Bellingen town on the right bank of the Bellinger River. The safe yield of the Bellingen

Borefield was estimated as 1,500 ML/a (source: Preliminary Safe Yield Assessment and

Audit of Bellingen Borefield, Parsons Brinckerhoff November 2003).

Raw water is extracted and transferred to Bellingen Water Treatment Plant (WTP)

before being pumped via a balance tank to either the Bellingen Town Reservoir or the

Marx Hill Reservoirs. Bellingen Water Treatment Plant has a capacity of 11.2 ML/d.

Potable water is supplied to Bellingen via Bellingen Town Reservoir and to the coastal

area of Raleigh, Repton, Mylestom and Urunga via the two Marx Hill reservoirs. At

Raleigh, the transfer network splits into separate mains to feed Urunga Reservoir and

Repton Reservoir. Water is pumped from Repton Reservoir into O’Connors Reservoir.


For the purpose of this demand management plan, the combined daily production

records from Marx Hill and Bellingen Town reservoirs were considered as daily

production data for the LBWSS.

Historical demand analyses were performed which included climate correction of the

existing production data to include the effects of climatic variation upon water

demand. Data used in the analysis is summarized in Table 5.

Table 5: Lower Bellinger Water Supply Scheme Demand Analyses Input Data

Data Required Data Used Comments

Population LBWSS Permanent Population excluding visitors:

6,712 in 1991

7,318 in 1996

7,725 in 2001

8,158 in 2006

8,334 in 2009


Populations Connected to

Water Supply System,

Bellingen Shire Council IWCM

Strategy, Public Works NSW

Water Solutions, Dec 2011)

Growth rate 0.5% per annum BSC staff

Daily Water

Production

8 years (2003 – 2011) of daily water production Data log from Bellingen Town

Reservoir and Marx Hill

Reservoirs from BSC (May

1994 – June 2011)

The historical demand data for LBWSS was then checked for accuracy to ensure

baseline production levels were suitable for water production forecasting. It is noted

that some production data were found to be inaccurate due to operational issues

(e.g. broken mains at Marx Hill Reservoirs in April 2009). Such data was adjusted to

reflect a more realistic set of daily production figures.

Bellingen town and particularly the coastal supply areas have very high visitor numbers

during the holiday seasons. The Trend Tracking Climate Correction model does not take

into account this population variation. The climate corrected calculations were initially

undertaken for the permanent population only. The impact of the production related

to visitors demand was then estimated using the outcomes from the model and an

estimated visitor production factor. The results were combined to calculate the total

climate corrected production data.

The outcomes of the demand analyses are summarised in the following sections.

Detailed description and outcomes of the climate corrected historical demand

analyses are provided in Appendix A. Detailed descriptions and outcomes of the

demand forecast analyses (DSS model) are provided in Appendix B.


3.6.2 Annual Demand Analysis

Bellingen Shire is licensed to extract 1,613 ML per annum for the LBWSS. The starting

point for LBWSS annual demand forecast analysis was the average annual water

production over the past 5 years (from 2007 to 2012).

The pricing structure was changed in 2008 to a two-tier water pricing. The average of

the 3 years annual consumption after that would be expected to be included as the

starting point. However, 2009 was unusually wet and was considered to not be

representative of normal consumption. For this reason, 5 years data has been used in

this analysis.

The annual water demand projections were estimated using Bellingen Shire’s

population growth rate of 0.5%.

Figure 5 shows the LBWSS historical and projected annual water demand. This analysis

shows that the annual water production is lower than the water extraction licence

entitlement and that the current extraction entitlement will be sufficient to supply the

Lower Bellinger water supply area’s long term annual demand.

Licensed Extraction 1613ML/y

900

1000

1100

1200

1300

1400

1500

1600

Annu

al A

vera

ge D

eman

d (M

L/ye

ar)

Lower Bellinger Water Supply Scheme Annual Demand

LicensedExtraction

Historical

Climate Corrected

Baseline Forecast

Figure 5: LBWSS Annual Demand Baseline Forecast


3.6.3 Per Capita Demand Analysis

LBWSS’s per capita demand forecast is shown in Figure 6. The per capita demand is

assumed to be steady for the 30 years planning horizon. The starting point of the per

capita demand forecast (365 L/d) is assumed by calculating the average of the past 5

years (from 2007 to 2011) of historical per capita production.

The outcome per capita production values are expected to be higher than the

estimated residential water consumption per capita of 230L/person/day in 2012. The

estimated state wide median consumption based on 2010/11 NSW Office of Water TBL

Performance Indicators was 250 L/person/day . This is due to the following variations:

annual water production data was used in the analysis which are higher than

annual consumption values;

annual water production values of all customer types including residential,

industrial, commercial and unaccounted for water. These values are higher

than residential water consumption which represents 54% of the total water

consumption in 2011.

250

270

290

310

330

350

370

390

410

430

Tota

l per

Cap

ita W

ater

Dem

and

(L/d

)

Lower Bellinger Water Supply Scheme Per Capita Demand

Historical

Climate Corrected

Baseline Forecast

Figure 6: LBWSS per Capita Demand Baseline Projections

3.6.4 Peak Day Demand Analysis

The LBWSS current design capacity is 11 ML/d. The maximum daily extraction limit from

the bores was increased to 5.5 ML/d in March 2012.


Figure 7 shows the historical and predicted peak day demand (PDD) for LBWSS. The

99.5 percentile of the past 3 years (from 2009 to 2011) daily production data was

applied as the starting value of the PDD forecast. This approach is used to ensure BSC

has sufficient capacity to supply PDD in the future (including visitors demand during

holiday seasons). Figure 8 shows that the WTP has sufficient capacity to supply PDD

baseline forecast until 2030.

Max Daily Extraction Limit 5.5 ML/d

WTP Capacity 11.2 ML/d

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

Peak

Day

Dem

and

(ML/

d)

Lower Bellinger Water Supply Scheme Peak Day Demand

Max DailyExtraction Limit

BaselineForecast

Historical

WTP designcapacity(ML/day)

Figure 7: LBWSS Water Supply Scheme PDD Forecast

Treated water from the Bellingen Water Treatment Plant (WTP) is transferred via a

balance tank to either the Bellingen Town Reservoir or the two Marx Hill Reservoirs. The

Bellingen Town Reservoir has a capacity of 0.88 ML and serves the inland area of

Bellingen Town. The two Marx Hill Reservoirs have a combined capacity of 3.39 ML and

they serve the coastal areas of Urunga, Repton, Raleigh, Fernmount and The Valley.

It is generally considered good practice that reservoirs have a capacity to supply 1 day

of PDD. Figure 8 indicates that Bellingen town’s peak day demand have already

exceeded the Bellingen town reservoir’s current capacity. Figure 10 indicates that

without a new Bellingen town reservoir, the Lower Bellinger scheme supply area peak

day demand is expected to exceed the combined reservoirs capacity by 2020.

Bellingen Shire Council has identified the need for storage capacity augmentation of

the existing Bellingen Town Reservoir and a concept design has been adopted by

Council.


0.0

0.5

1.0

1.5

2.0

2.5Pe

ak D

ay D

eman

d (M

L/d)

LBWSS Peak Day Demand (Bellingen Town Reservoir)

Bellingen TownProposed NewReservoir Capacity

Annual PDDBellingen

Bellingen TownReservoir Capacity

Bellingen Town Proposed New Reservoir Capacity, 2 ML

Bellingen Town Reservoir Current Capacity, 0.88 ML

Figure 8: Bellingen Town Reservoir Capacity & Peak Day Demand

1.5

2.0

2.5

3.0

3.5

4.0

Peak

Day

Dem

and

(ML/

d)

LBWSS Peak Day Demand (Marx Hill Reservoirs)

Marx Hill ReservoirsCapacity

Annual PDD MarxHill

Marx Hill Reservoirs Capacity, 3.39 ML

Figure 9: Marx Hill Reservoirs Capacity & Peak Day Demand


3.0

3.5

4.0

4.5

5.0

5.5

6.0Pe

ak D

ay D

eman

d (M

L/d)

LBWSS Reservoirs Peak Day Demand

Proposed CombinedReservoirs Capacity(Marx Hill & newreservoir)

LBWSS BaselineForecast

Current CombinedReservoirs Capacity(Marx Hill &Bellingen Town)

Combined Reservoirs Capacity (Marx Hill & Bellingen Town Reservoirs), 4.27 ML

Proposed Combined Reservoirs Capacity (Marx Hill & new reservoir), 5.39 ML

Figure 10: Combined Reservoirs Capacity & Peak Day Demand

3.6.5 Demand Forecast for Each Customer Category

As it’s mentioned in previous section, BSC’s water consumption records are grouped

into water sales for residential and non-residential only, demand forecast analysis for

each customer category was performed by using existing consumption data from

BSC’s IWCM Strategy (Dec 2011) (Table 6). Growth rates were assumed at 1.1% per year

in the first 10 years and 0.7% per year thereafter (source: Data provided by Bellingen

Shire Council).

Table 6: Lower Bellinger Water Supply Historical Customer Consumption

(Source: Bellingen Shire Council IWCM Strategy, Public Works NSW Water Solutions, Dec 2011) Note: 1: Natural System Extraction and WTP production data available until 16/4/09

2. Customer consumption data available until April 2009 3. Restricted Years


In the analyses of demand forecast by customer type for LBWSS as shown in Figure 11, it

is assumed that the current ratios between each customer type’s water consumption

will remain the same over the 30 year planning horizon.

LBWSS Demand Forecast by Customer Type

0

50

100

150

200

250

300

350

400

450

500

1995

1998

2001

2004

2007

2010

2013

2016

2019

2022

2025

2028

2031

2034

2037

2040

Cus

tom

er C

onsu

mpt

ion

(ML/

y)

Residential

Commercial

Farms

Tourism

RuralResidential

Council

Institution

Industrial

Figure 11: Lower Bellinger Scheme Demand Forecast by Customer Type


4 Demand Management Planning

4.1 Water Demand Management Drivers

The main drivers for implementing demand management in Bellingen Shire considered

in this study are:

To ensure safe and secure potable water supply in Bellingen Shire;

To project water demand from Bellingen Shire Council water schemes in order

to determine if water demand management actions will be required;

To satisfy the Best-Practice Management of Water Supply and Sewerage

requirement to promote sustainable water conservation practices and water

demand management by developing a compliant water conservation

demand management plan;

To reduce capital works (new reservoirs and sewerage treatment plant) costs.

Other reasons for demand management in BSC were also considered in this study.

These are discussed in the following sections.

4.1.1 Impact of Climate Change

Based on the “Climate Change in the Northern River Catchment” Report prepared by

CSIRO in 2007, the projected changes from 2007 to 2030 and 2070 are summarised in

Table 7.

Table 7: Climate Change in the Northern River Catchment

Projected Climate Change 2030 2070

Average Temperature 0.2 to 1.8ºC 0.7 to 5.6ºC

Annual Average Rainfall ±7% ±20%

Extreme Rainfall -10 to +5% 5 to 10%

Evaporation 1 to 13% 4 to 40%

(Source: Climate Change in the Northern River Catchment, CSIRO 2007) The report also stated that “changes in rainfall and higher evaporation rates are likely

to lead to less water for streams and rivers in the Northern Rivers Catchment, which will

have downstream consequences for storages and place strains on the catchment’s

water resources. However, given increases in extreme rainfall events that periodically

deliver large volumes to storages, the effects of long term reductions in average rainfall

on storages may be moderate.”


4.1.2 Non-revenue Water

Definition

The International Water Association (IWA) has adopted the following terminology for

water leakage within a water supply scheme:

Real losses are physical water losses from the distribution system up to the point

of customer metering. They can occur through leaks, bursts and reservoir

overflows.

Apparent losses reflect errors in measurement and/or the documentation

process. They generally consist of customer use which is not recorded due to

metering error (mostly under-registration of worn customer meters), incorrect

assumptions of unmeasured use or unauthorised consumption (illegal use),

Water losses are the sum of Real Losses (mostly leakage) and Apparent Losses

(meter errors, illegal uses).

Non-revenue water (NRW) consists of water losses plus unbilled authorised

consumption. Unbilled authorised consumption may or may not be metered

and may include fire fighting and mains flushing. Any watering of parks and

gardens should be metered and billed by each LWU.

(Source: NSW Water Supply and Sewerage Benchmarking Report 2010/11)

Bellingen Shire Water Losses

BSC’s real loss (leakage) based on the 2010/11 benchmarking report was 0.7 kL per

connection per day (Source: 2010/11 NSW Water Supply and Sewerage, Benchmarking Report,

NSW Office of Water, April 2012). The average real loss (leakage) state wide median for all

LWUs was 0.60 kL per connection per day.

Dorrigo Non-revenue Water

DWSS’s non-revenue water analysis is from the BSC’s IWCM Strategy. The typical water

usage split for DWSS is shown in Figure 12. Detailed NRW results are shown in Table 8.

Table 8: Dorrigo Water Non Revenue Water



Figure 12: Typical Water Usage Split for DWSS

(Source: Bellingen Shire Council IWCM Strategy, Public Works NSW Water Solutions, Dec 2011)

The results show that DWSS NRW reduced almost every year from 2001 to 2009. This is

likely to be due to the System Water Loss Management program implemented by

Council (see section 4.2.2). Appropriate data from 2010 to 2012 was not available at

the time of this study; therefore NRW for these years is unknown.

Lower Bellinger Non-revenue Water

LBWSS’s non-revenue water analysis is from the BSC’s IWCM Strategy. The typical water

usage split for LBWSS is shown in Figure 12. Detailed NRW results are shown in Table 9.

Table 9: Bellingen Water Non Revenue Water



Figure 13: Typical Water Usage Split for LBWSS

(Source: Bellingen Shire Council IWCM Strategy, Public Works NSW Water Solutions, Dec 2011)

The results show that LBWSS NRW reduced almost every year from 2000 to 2008, with a

great improvement in 2009. This is likely to be due to the System Water Loss

Management program implemented by Council (see section 4.2.2). Figure 13 show

that the typical NRW in the LBWSS is 22%. Council should maintain the water loss

program to envisage reducing the LBWSS NRW. Appropriate data from 2010 to 2012

was not available at the time of this study.

4.2 Demand Management Measures in Place

This section provides a list of the water demand management measures that are

currently implemented by BSC. These are:

Community Education;

System Water Loss Management.

4.2.1 Community Education

Council advised that there are existing community education programs which provide

materials, training and technical assistance to implement water conservation measures

within the Bellingen Shire water supply area.

Bellingen Shire Council is a member of the Savewater Alliance which offers a

combination of web resources and water conservation programs throughout Australia.

Based on the DSS model analysis undertook for the LBWSS, community education

programs are expected to have a 30 year average water savings of 13.0 ML/year.

http://www.savewater.com.au/


4.2.2 System Water Loss Management

In May 2006, a project was carried out to evaluate the existing conditions of the

Bellingen Shire water distribution scheme. Water distribution losses and efficiency issues

were assessed and a Strategic Water Demand Management Program was developed.

The comprehensive water loss management project involves:

Leak detection and repairs;

Sectorisation of the system to create district metered areas or zones;

Pressure reduction in some of the high pressure areas.

The project implementation work was delayed significantly due to major floods in the

area in 2009 (source: Water Loss Management Program - Project and Investigation

Locations [updated 6 April 2010], Local Government and Shires Associations of NSW

website).

Council has advised that the implementation of the System Loss Management Plan

was completed in May 2011 and that the water savings from implementing the

program is 47 ML per year. The DSS model estimates water savings of 6 ML per annum

from implementing the system water loss management measure (source: Water Loss

Management Program – Project completion details, BSC May, 2012).

4.3 Demand Management Scenarios

Four demand management scenarios were developed with assistance from Bellingen

Shire Council and they are summarised in Table 10. The DSS model evaluates the

benefit-cost and water savings of implementing the scenarios. Detailed description

and outcomes from the DSS model for each scenario and individual water

conservation measure are provided in Appendix B.

Table 10: Water Demand Management Scenarios

Water Conservation Measures

Sce

nari

o 1

Sce

nari

o 2

Sce

nari

o 3

Sce

nari

o 4

National Mandatory Water Efficiency Labelling Scheme (WELS) X X X X

Community Education (existing)

Residential Shower Retrofit X X X X

Residential Washing Machine Rebate X X

Permanent Low Level Restrictions on Water Use

Conservation Pricing for Residential Users X X X



Sce

nari

o 1

Sce

nari

o 2

Sce

nari

o 3

Sce

nari

o 4

Fixture Code - Taps and Showers - New Development X X

Non-Residential Water Audits

System Water Loss Management (existing)

Rainwater Tanks for all New Residential Development

Dual Reticulation for all New Residential Development

BASIX - Fixture Efficiency with Rainwater Use X X

BASIX - Fixture Efficiency with Dual Reticulation X

Evaporative Cooling Unit and Cooling Tower Audit

For each demand scenario, the DSS model forecasts the 30 years average annual

water savings and the associated community and LWU benefit/cost ratio figures. The

water savings increase over the years due to growth and percentage of customers

take up. The benefit/cost ratio is the ratio of total benefits and costs arising from a

demand management effort. The higher the ratio the better the demand

management measure benefits.

The outcomes of these analyses provide a guide for selecting the preferred demand

management options to be implemented in BSC. Figure 14 shows that scenario 3 has

the second highest average water savings and a moderate benefit/cost ratio for both

the utility and the community. Based on the demand model outcomes, Scenario 3

appears to be the preferred scenario.


0

20

40

60

80

100

120

140

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

1 2 3 4

ML/

year

Ben

efit/

Cos

t Rat

io

Scenarios

Utility B/C Ratio Community B/C Ratio Average Water Savings (ML/a)

Figure 14: Water Demand Management Measures Scenarios Outputs

Demand management measures options recommended for BSC on the basis of the

DSS model outcomes are detailed in section 4.4.

4.4 Potential Demand Management Measures

4.4.1 Introduction

This section provides a list of potential water demand management measures that BSC

shall further implement, if required, through its Management Planning process. These

demand management measures are outcomes of the DSS model prepared for the

LBWSS only. The outcomes of this model are expected to be equivalent in other parts of

the shire. Therefore the demand management actions may be implemented at any

town or village across the Bellingen Shire.

The result of the Demand Forecast analysis indicates that scenario 3 is the

recommended option for demand management in Bellingen Shire. This is due to its

moderate average water savings and high utility benefit/cost ratio. The potential

demand management measures included in scenario 3 and their stand-alone benefits

are listed below.


The following demand management measures are provided in priority order of utility

benefit/cost ratio for Council’s consideration. The following sections show the water

saving and utility and community savings from implementing these demand

management measures based on Council’s current usage charge and operational

costs. Appendix B provides details about the demand management measures

definition and assumptions used in the DSS model. The assumptions used to calculate

the benefits of the following water demand management measures are provided in

Table 20 in Appendix B.

4.4.2 Conservation Pricing for Residential Users

DSS model outcomes:

Utility B/C ratio: 120.1

Community B/C ratio: 120.2

30 year Average Water Savings: 57.4 ML/year

Conservation Pricing for Residential Users is an efficient demand measure for Lower

Bellinger supply scheme. It has the highest utility and community benefit/cost ratio and

highest average water savings.

The estimated 30 year average water savings is 57.4 ML/year. Based on the current first

tier water usage charge of $1.60/kL, the average annual savings for the BSC customers

is $91,808. The current Council’s potable water production operational costs is 1.10 $/kL

therefore the average annual savings for the utility is $63,118 (it does not include

savings from reduced sewerage operations).

Comments:

Based on the definitions of conservation pricing for residential users, the inclining block

tariff is applied to single family residential customers and the increase would result in an

effective 50% increase in price for residential external use and no change in price for

internal use.

Council advised that there was a change in water supply pricing structure in 2008. Two

tier water pricing was applied from 2008/09 onwards. In 2012/13, residential water

usage is charged on the basis of on an inclining block tariff. The consumption above

365 kL per year is charged at $2.52, i.e. one and a half times the standard rate of $1.68.

Current water usage is billed in the periods in May, August, November and February

each year.

From the Water Demand Trend Tracking and Climate Correction analyses, the average

annual residential indoor water use was estimated as 200 kL per property per annum.


While Council’s existing pricing structure satisfies the conservation pricing inclining block

tariff structure of 50% increase in price for residential external use, the internal/external

use threshold appears to be not aligned with the demand measures definitions.

Implementation of this measure is therefore recommended.

4.4.3 Residential Washing Machine Rebate Program

DSS model outcomes:




Although this water conservation measure is assumed to be partly funded by the LWU

(20% rebates) it does not represent significant benefit to the community due the high

cost of the washing machine, installation and running costs. However the average

water saving is reasonably high and the utility benefit/cost ratio is relatively good when

compared to other water conservation measures.

If BSC decides to provide rebates for washing machine and implement this program,

the estimated 30 year average water savings is 12.3 ML/year. The current water usage

charge is 1.60 $/kL, therefore the average annual savings for the customers is $19,736.

The current Council’s potable water production operational costs is 1.10 $/kL therefore

the average annual savings for the utility is $13,569 (it does not include savings from

reduced sewerage operations).

Water savings from implementing residential washing machine rebates represents

about 1.1% of the LBWSS baseline forecast annual water production in of 1,111 ML in

2011.

4.4.4 National Mandatory Water Efficiency Labelling Scheme (WELS) program

WELS is Australia's water efficiency labelling Scheme that requires certain products to

be registered and labelled with their water efficiency in accordance with the standard

set under the national Water Efficiency Labelling and Standards Act 2005. Council’s

role in regards to demand management is to encourage customers to purchase

products labelled accordingly with the WELS program.

DSS model outcomes:





The Water Efficiency Labelling Scheme was introduced in 2005. The program has made

water efficient products more accessible. The DSS model assumes that uptake of water

efficient products is continuing. However it does not seem to be a very efficient

demand measure for LBWSS. Also its community and utility benefit/cost ratio are low

compared to other demand measures in scenario 3.

The estimated 30 year average water savings is 7.8 ML/year. The current water usage





Water savings from continuing using water efficient products represents about 0.7% of

the LBWSS baseline forecast annual water production in of 1,111 ML in 2011.

4.4.5 Residential Shower Retrofit

DSS model outcomes:




Residential shower retrofit program is not a very efficient demand measure for LBWSS.

Low flow shower heads reduce water usage, reducing water and energy bills.

The estimated 30 year average water saving is 0.8 ML/year. The current water usage



the average annual savings for the utility is $859 (it does not include savings from


Water savings from implementing residential shower retrofit represents about 0.07% of

the LBWSS baseline forecast annual water production in of 1,052 ML in 2011.

4.4.6 BASIX - Fixture Efficiency with Rainwater Use

The Building Sustainability Index (BASIX) is a NSW government requirement that affects

anyone building a new house, villa, townhouse or apartments. The purpose of BASIX is

to ensure that all new homes are built to be more energy and water efficient. BASIX sets

specific targets for energy and water reduction in new homes.

To meet these targets, simple design features and fixtures are needed. Because BASIX is

a flexible tool, there are a wide range of options in order to meet the targets. Fixture

efficiency with rainwater use is one of these tools. In this particular study, this tool was

recommended for BSC customers in order to reduce the demand consumption.


This measure includes the installation of rainwater tanks in new developments.

DSS model outcomes:




According to the DSS model the implementation of efficient fittings with rainwater use

in new residential developments in Bellingen is a relatively beneficial water savings

demand management measure. However the utility and the community benefit/cost

ratio are low. This means that this demand management measure is a great water

savings measure however it does not comprise many benefits to the utility or to the

community.

Upon Council’s request, a 10 % take up rate was also considered for customer to retrofit

water efficient fixtures to the existing rainwater tank. There is no existing study on the

existing number of rainwater tank usage in Bellingen Shire. For the purpose of this

analysis, an assumption was made that the number of customer with existing rainwater

tank is approximately 15 % of the total number of existing residential accounts.

The estimated 30 year average water saving is 25.2 ML/year. The current water usage





Water saving from installing efficient fittings with rainwater use in new developments

represents about 2.1% of the LBWSS baseline forecast annual water production of 1,111

ML in 2011.

Rainwater Tanks Assessment

Since July 2004 the NSW Government implemented the Building Sustainability Index

(commonly referred to as BASIX) with the purpose of reducing the use of potable water

and to produce less greenhouse gas emissions. One of the BASIX requirements is a

rainwater tank for all new developments.

Council staff has advised that 100% of the new developments BASIX certificates have a

commitment for a rainwater tank and that the current rainwater tanks take up in the

Shire is approximately 5% of the customers connected to the water supply scheme. This

is an assumption made by Council staff through observation; there is no study data on

the actual number of rainwater tanks currently used within the serviced area.


The rainwater tank assessment indicates that installation of 3 kL tanks would be

beneficial to BSC to assist potable water consumption reduction. A rainwater tank

assessment also has been undertaken for the Lower Bellinger water supply area to

calculate the benefits of rainwater tanks to water demand and water bill saving per

residential household. A summary of the results (3 kL rainwater tank with outside usage

only) is listed below. See Appendix C for a detailed description of the rainwater tank

assessment.

Rainwater cost per kilolitre ($1.40/kL) compared to cost of town water supply

($1.60/kL in 2010/11);

If rainwater tanks uptake is 100% in 30 years, then mains water saving in Lower

Bellinger water supply area in 30 years will be 74%.

Based on the outcomes of the rainwater tank assessment it appears that using 3 kL

capacity rainwater tanks (outside usage only) would represent a considerable

demand reduction (average 83 kL/year) in LBWSS.

4.5 Summary and Comparison

A summary of the further demand management measures recommended to BSC are

compared in Table 11. The comparison analyses includes the percentage of expected

water savings per year and utility and community savings related to reduction in water

production and consumption, respectively.

Table 11: Water Conservation Measures Comparison


Utility Community Savings Expected Water

Savings

Customer average savings

Utility average savings

B/C Ratio (ML/year) (%/year) ($/year)* ($/year)*


8.4 0.7 7.8 0.7% $12,400 $8,525


7.6 21.1 0.8 0.1% $1,249 $859


42.7 0.7 12.3 1.1% $19,736 $13,569


120.1 120.2 57.4 5.2% $91,808 $63,118

BASIX - Fixture Efficiency with Rainwater Use (including installation of rainwater tanks in new developments)

0.7 0.7 25.2 2.3% $40,310 $27,713

Total Annual Savings 103.4 9.3% $165,504 $113,784

*Customer average savings is calculated based on usage charge of $1.60 and utility average savings is calculated based on operational cost per property of $1.10.


If BSC decides to implement all the water conservation measures recommended

above, the 30 years average water savings per year in Lower Bellinger water supply

scheme will be approximately 99.6 ML per year, benefit cost ratios to the utility would

be 2.8 and BCRs to the community would be 0.9. The estimated costs for

implementation of each of the water demand management measures during first 5

years are summarised in section 5.

Figure 14 displays detailed demand analyses of the impact of demand scenarios on

each water supply scheme, Dorrigo and Lower Bellinger. The baseline demand

forecast and demand forecast including demand management measures are

provided in sections 3.5 and 3.5 respectively.

4.6 30 year projected Water Savings Outcomes

The following section provides the 30 years estimated water saving by implementing

demand management measures (preferred scenario 3) in the LBWSS and DWSS supply

areas.

4.6.1 Lower Bellinger Water Supply Area

Figure 15 shows that the preferred demand scenario (scenario 3) provide a 9% annual

demand reduction from the baseline annual average demand in 2041.

Licensed Extraction 1613ML/y

900

1000

1100

1200

1300

1400

1500

1600

Annu

al A

vera

ge D

eman

d (M

L/ye

ar)

Lower Bellinger Water Supply Scheme Annual Demand

Licensed Extraction

Historical

Climate Corrected

Baseline Forecast

Scenario 1

Scenario 2

Scenario 3

Scenario 4

Figure 15: LBWSS Annual Demand Forecast


The annual demand reductions in 30 years for each of the water demand scenario are

summarized in Table 12.

Table 12: LBWSS per Capita Demand Scenarios Comparison in 30 years

Scenario Reduction from Baseline Demand

in 2041 (ML/year) % of Reduction from Baseline Demand

1 26.8 2.1%

2 91.3 7.1%

3 132.8 10.4%

4 177.1 13.8%

If the water demand management measures of Scenario 3 were implemented, the

total per capita demand would be expected to decline as shown in Figure 16. The per

capita demand reductions in 30 years for each of the water demand scenario are

summarized in Table 13.

250

270

290

310

330

350

370

390

410

430

Tota

l per

Cap

ita W

ater

Dem

and

(L/d

)

Lower Bellinger Water Supply Scheme Per Capita Demand

Historical

Climate Corrected

Baseline Forecast

Scenario 1

Scenario 2

Scenario 3

Scenario 4

Figure 16: LBWSS per Capita Demand Projection


Table 13: LBWSS per Capita Demand Scenarios Comparison in 30 years

Scenario Reduction from Baseline Demand

in 2041 (L/person/day) % of Reduction from Baseline Demand

1 10.3 2.8%

2 35.8 9.8%

3 52.2 14.3%

4 69.7 19.1%

As shown in Figure 17 LBWSS peak day demand is unlikely to reach the capacity of the

maximum daily extraction limit by 2013. Implementing the preferred demand

management (scenario 3) will reduce PDD and enable Council to delay the need for

new infrastructure beyond 2041.

WTP Capacity 11.2 ML/d

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

Peak

Day

Dem

and

(ML/

d)

Lower Bellinger Water Supply Scheme Peak Day Demand

Historical

BaselineForecast

Scenario 1

Scenario 2

Scenario 3

Scenario 4

WTP Capacity

Figure 17: LBWSS PDD Forecast

4.6.2 Dorrigo Water Supply Area

Section 3.5.3 indicated that Dorrigo residential per capita demand can be further

reduced by implementing the recommended demand management measures in

scenario 3. The expected reduction percentage is assumed to be similar to LBWSS. The

results of per capita reduction are shown in Figure 18.


300.0

350.0

400.0

450.0

500.0

550.0To

tal P

er C

apita

Wat

er D

eman

d (L

/d)

Dorrigo Per Capita Demand Analysis

Historical Demand Projections Scenario 3

Figure 18: DWSS per Capita Demand Analysis


5 Proposed Implementation Plan

5.1 Overview

BSC demand management drivers are listed in section 4.1. Council has 2 demand

management measures in place. If Council decides to implement further demand

management measures, Council shall use this analysis as a guideline to select a

potential option.

This section shows a 5 years implementation plan of the potential water demand

management measures analysed for the Lower Bellinger water supply area. Table 14

lays out Council’s estimated costs in the first 5 years of implementation. They are

estimates only; further investigation and on-going review of the program will be

needed to identify the actual costs. The final implementation would be determined by

Council in its annual Management Planning process.

Table 14: Potential Water Conservation Measures Implementation Plan

Water Conservation Measure Year 1 Year 2 Year 3 Year 4 Year 5


$9,063 $4,793 $4,736 $806 $807

Residential Shower Retrofit $2,757 $2,760 $2,764 nil nil


$3,290 $3,227 $3,173 nil nil


$6,204 nil nil nil nil


$52,181 $29,891 $30,010 $30,130 $30,251

Total Annual Implementation Cost for LWU

$73,496 $40,671 $40,684 $30,936 $31,058

5.2 5 years Demand Management Implementation Outcomes

The costs and water savings within 5 years related to the implementation of the water

demand management measures recommended to BSC as well as the average annual

savings to customers and to the LWU are provided in Table 15.

If Council decides to implement all the water demand management measures listed

below, the water savings in 5 years will be 28% of the projected baseline forecast

demand for 2015/16. Council’s total cumulative expense for the 5 year implementation

of these options is likely to be in the order of $217 K (2011 dollars).


Table 15: Water Savings and Costs Comparison of the First Five Years of Implementation (2011 dollars)

Water Demand Management Measures

Total LWU Expenses in 5

years

First 5 Years Expected Water

Saving (ML)

Total customers savings in 5

years ($)

Total utility savings in 5

years ($)


$20,205 19.9 $31,844 $21,892


$8,281 5.9 $9,439 $6,489


$9,690 27.0 $43,244 $29,730


$6,204 217.3 $347,601 $238,976


$172,464 30.6 $48,998 $33,686

Total $216,845 300.7 $481,126 $330,774

Some of the water demand management measures recommended will have a

quicker turn over than others, but generally they have financial benefits. This is a

preliminary cost analysis using water savings and costs assumptions from NSW Office of

Water guidelines and DSS model. If BSC determines the demand management

measures should be implemented, Council should further investigate the options and

local costs of implementing the options.

If the water conservation measures are implemented Council should develop a

monitoring program for reviewing the effectiveness of the implemented demand

management measures.


6 Reference

1. Bureau of Meteorology -SILO data recorded at 30.45°S 152.90°E

2. Bellingen Shire Council IWCM Strategy, Public Works NSW Water Solutions, Dec

2011

3. NSW Office of Water, Best-Practice Management of Water -Supply and

Sewerage Guidelines, Aug 2007

4. Bellingen Shire Council IWCM Strategy – Concept Study, Public Works NSW

Water Solutions, Oct 2007

5. NSW Water Supply and Sewerage Benchmarking Report 2010/11

6. Water Demand and Trend Tracking Climate Correction Manual (Version 10)

Manual, May 2002

7. Bellingen Shire Council 2010/1 TBL Performance Reports for water supply and

sewerage

8. Data provided by Bellingen Shire Council

9. Bellingen Shire water access licence (WAL6426) for Dorrigo water supply, issued

May 2005


Appendix A

Water Demand Trend Tracking and Climate Correction Methodology


Introduction

The methodology for this analysis was performed according to the manual developed

by NSW Office of Water (May 2002). The methodology is described below.

Set up

The model tables were set according to the period of data available. The data

provided (population, daily water production and climate) was inserted into those

tables and estimated population and observed water production per capita (daily)

were calculated as well as soil moisture data.

Bellingen particularly in the coastal area has a very high visitor number during the

holiday seasons. The model does not take into account the population variation.

Therefore the climate corrected calculations are undertaken for the permanent

residing population only. The impact of the visitors’ production in the Lower Bellinger

Scheme water production is calculated using the outcomes of the model, which

provides an estimated visitors production factor. This is then added to the final climate

corrected production data.

Input Data

Table 16: Demand Trend Tracking and Climate Correction Model Input Data

Data Required

Data Used Comments

Population LBWSS Permanent Population excluding visitors:

6,712 in 1991

7,318 in 1996

7,725 in 2001

8,158 in 2006

8,334 in 2009


Populations Connected to Water

Supply System, Bellingen Shire Council

IWCM Strategy, Public Works NSW

Water Solutions, Dec 2011)

Climate 60 years of daily rainfall, maximum temperature

and evaporation

Data from Bureau of Meteorology SILO

services recorded at 30 27°S 152 54°'E

Daily Water

Production

8 years of daily water production data were

selected from the records provided by Council

Data log from Bellingen Town Reservoir

and Marx Hill Reservoirs from BSC (May

1994 – June 2011)

Data was checked for accuracy and errors so that baseline production levels suitable

for forecasting could be prepared. Some of the production data was very high having

one or two previous days with blank data. Council has reviewed and confirmed missing

and unrealistic data to obtain a better model outcome.


The climate correction model also requires the identification and definition of three

parameters:

Period for index calibration – calibration of Soil Moisture Index;

Start and end date for calibration – to run the regression analyses;

Fixed baseline water production per capita – non-seasonal water production.

This data has been identified and defined by the model user (HSc) according to the

data available/provided. The selection criterion to determine this data is provided in

the following sections.

Soil Moisture Index Calibration

The selection criterion recommended by the Water Demand Trend Tracking and

Climate Correction Manual for the period for index calibration is a period

(approximately 2 years) of reasonable water production compared against climate

data and that incorporates decent rainfall data and some hot days. It is important to

avoid periods of water restrictions and/or pricing change. Bellingen Shire’s climate

data for the last 6 years is shown in Figure 19. The period for index calibration chosen is

from December 2006 until December 2008. This period had some decent rainfall and

some hot days and it was considered the best period for calibration of the model.

Bellingen Shire Climate Data

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(°C

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nfal

l (m

m)

Maximum Temperature Rainfall

Figure 19: Bellingen Shire Daily maximum temperature and rainfall

(Source: Bureau of Meteorology -SILO data recorded at 30.45°S 152.90°E)


Regression Analyses

The model uses multivariable regression analysis of climate on daily water production to

produce a calibrated model for a specific baseline period. This period is determined by

the model user and it should contain stable demand pattern; there shouldn’t be any

restrictions and the more rainfall events the better.

The regression analyses takes into consideration four variables: maximum temperature,

rainfall, evaporation and soil moisture index. These variables should fit in a particular

way to produce a calibrated model (i.e. the higher the temperature the higher the

evaporation).

Bellingen observed water production per capita is shown in Figure 20. This graph

excludes the winter holiday season production due to high number of visitors in town

(see “SET UP’ section above for further information). The period chosen is from

December 2006 until December 2009. In general this period of water consumption per

capita complies with the requirements mentioned above e.g. (very hot days – hotter

than average - in January and February 2009 and several rainfall events)

Observed Water Production vs Max Temperature

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600

700

800

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Max

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Observed Water Production Per Capita (L/d) Baseline FixedMaximum Temperature 30 days moving avg (max temp)30 days moving avg (observed water consumption per capita)

Figure 20: LBWSS Observed Water Production per Capita


Fixed Baseline Water Production

The fixed baseline water production per capita is the household internal water

consumption per capita. It is estimated based on the observed daily water production

data graph (see Figure 20 above). In general it is the average of the 20 or 30 (depends

on the frequency of the records) lowest daily records of water production within the

period analysed.

LBWSS’s fixed baseline water production per capita is assumed to be 230 L/p/d (see

Figure 20). Using this figure it can be assumed that 56.7% of the water production is

used for fixed consumption (indoor use) and 43.3% for seasonal (outdoor use)

consumption.

Trend Tracking/Outcomes

Once the model is calibrated and the fixed baseline is determined, the model is ready

to update the regression calculations and to calculate the water demand trends. The

output is a climate corrected water production per capita Figure 24.

The steps and input data to run the model are detailed in the following table.

Table 17: Water Demand Trend Tracking and Climate Correction Model Input Data

Steps Item Comment LBWSS

Setup tables

Hindcasting 60 years of daily climate data 1950 – 2010

Climate Data

Trend Tracking

17 years of daily water production. However

Council advised that Level 1 water

restrictions were applied over two periods in

the past 10 years, 5 Jan to 6 Feb 2002 and

23 Oct 2002 to 25 Feb 2003. Production

data was therefore selected from June 2003

onward.

01 May 1994 – 30 June

2011

Trend

Tracking

Data

Observed Daily

Total Water

Production (ML)

The production data were selected from

the recent 8 years excluding the tourist

load. Council advised that peak tourist

periods in Bellingen Shire are during mid-

December to mid-January and in the

month of April. Production data during

these peak tourist periods were extracted

from the observed daily water production.

30 June 2003 - 30 June

2011

Population

Data Population 5 years of population data

1991, 1996, 2001, 2006

and 2009 population

from IWCM Strategy

Dec 2011



Trend

Tracking

Data

Calculate population and observed per

capita - Development of a baseline

production volume from combined daily

recorded production data from Bellingen

town reservoir and the Marx Hill reservoirs

-

Climate Data

Maximum

Temperature,

Rainfall and

Evaporation

Update Soil Moisture Data – Enables the

update of soil moisture index data when

new climate data is added to the time

series

-

Soil moisture

Control

Period for Index

Calibration

Period for Index Calibration is assumed to

be 2 years of a hotter and drier than

average summer. Figure 19 is used to

determine the period for index calibration.

January 2005 – January

2006

Calibrate Soil Moisture Index – Soil moisture

index is used to model the antecedent soil

conditions that impact on external water

use. Result of 1 represents a perfect

correlation, while 0 represents no

correlation.

Correlation coefficient:

0.6553

Regression

Control

Start to End

Date for

Calibration

Date for calibration is assumed to be a

period of reasonable water consumption

per capita – Figure 20 is used to determine

the year

January 2005 – January

2006

Variable

Control

The water tracking software uses multi-

variable regression analyses of climate and

other influences on daily water production

records to produce a calibrated model for

a specific baseline period.

Soil Moisture, rainfall,

maximum temperature

and evaporation have

been selected to

provide the best

outputs of the

regression analyses

Regression

Control

Regression

Analyses

R Squared – is the proportion of the variation

in the model that is explained by the

regression model. Ideally it should be

between 0.7 and 1

R2 - 0.7619. This result is

within the range of

acceptable R2 value

F statistic – Provides a test of the

significance of the model as a whole, if it is

less than 100 the model has no significance

F Statistic – 288.85

Durban-Watson Statistic - The value lies Durban-Watson



between 0 and 4. If the Durbin–Watson

statistic is substantially less than 2, there is

evidence of positive serial correlation.

Statistic – 1.737

Variable

Response

Data

The non-linear responses of the dependent

variable to the climate variables are

calculated in this sheet

Reasonable correlation

of non-linear variable

responses

Hindcast

Data

The model hindcast determines the long-

term climate influence on demands. It

projects the demands that would have

resulted in the baseline year for each day in

the hindcast period.

See Figure 21

Hindcast

Frequency

Data

In order to estimate the changes in the level

of external use (seasonal/climate – driven

use); the model needs the distribution of

daily demand throughout the hindcast

period. This provides an estimate of the

long-run frequency distribution of demands.

Figure 22 provides this

data

Trend

Tracking

Data

Baseline Year

In general it is the average of the 20 or 30

(depends on the frequency of the records)

lowest daily records of water production

within the period analysed.

Water Production per

Capita: 230 L/d of fixed

demand = 56.7% (not

seasonal)

Update

Regression

Calculations

Recalculates the predicted baseline year

water production and the residual

(difference between observed and climate

corrected data)

See Figure 23

Trend

Tracking

Data

Climate

Correction

Observed

Water

Production per

Capita

The trend tracking table provides detailed

information regarding the changes in

demand relative to the baseline period.

The climate correction is calculated and

added to the observed per capita demand

to produce the climate-corrected observed

per capita demand.

See Figure 24.

(Source: Water Demand and Trend Tracking Climate Correction Manual (Version 10) Manual, May 2002; Data provided by Bellingen Shire Council)

Hindcast

The model hindcast provides a sanity check on the regression model, see Figure 21. This

model provides sensible demand estimates throughout the full period of climate

record, including a regular winter demand pattern. Therefore it is considered a stable

regression model.


Hindcast

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700

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Jun 1

1

Predicted Baseline Year Water Production Per Capita (L/d)

Figure 21: LBWSS Regression Model Hindcast

Typical Baseline Hindcast Frequency Distribution

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Range Mid Point (L/person/day)

Freq

uenc

y

Figure 22: Typical Baseline Hindcast Frequency Distribution

Observed daily water production per capita

Figure 23 shows the observed daily water production per capita and the predicted

baseline year water production per capita. The later represents the demand that

would have been experienced in the baseline year for the climate conditions

encountered in the calibration period.


The residual is the difference between the observed per capita and the predicted

baseline year per capita production.

Water Production per capita (L/d)

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Observed Water Production Per Capita (L/d)Predicted Baseline Year Water Production Per Capita (L/d)Residual (L/d)

Two-tier pricing applied since 2008/09

Figure 23: Observed, Predicted and Residual Water Production per Capita

Outcomes

The main outcome of the model is the “climate corrected observed per capita

production”. The sum of the calculated climate correction and the observed per

capita demand is the climate-corrected observed per capita demand; this is shown in

Figure 24.


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apita

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aver

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Observed Water Production Per Capita (L/d)Climate Corrected Observed Water Production Per Capita (L/d)

Figure 24: Observed and Climate Corrected Observed Water Production per Capita

The climate corrected and observed water production per capita for the LBWSS were

found to be 409.3 ML/year and 406.9 ML/year respectively before the two-tier pricing

applied. The climate corrected and observed water production per capita for the

LBWSS were found to be 344.1 ML/year and 335.6 ML/year respectively from 2008/09

onward. It is noted that the water production data used in this analysis includes all

customer types e.g. residential, industrial, and commercial, parks and gardens.

Therefore the per capita production figure (outcome of the model) is usually higher

than the actual residential per capita production. According to the water consumption

by customer type data provided by Council, the residential water consumption in

LBWSS area represented about 54.3% of the total water consumption in 2010/11.

These figures are used in the DSS model to determine LBWSS’s demand forecast. A

summary of the demand forecast analyses and outcomes are provided in Appendix B.


Appendix B

Demand Side Management Support System (DSS) Methodology


Introduction

The DSS model is divided in three main sections:

Set up - Input data

Identification of Demand Management Scenarios

Historical Demand and Forecast Demand graph outputs

Set up

The data available was inserted into the model’s input information section. Some of

the data was assumed by HydroScience based on data analyses and conversation

with Council staff. In these cases the reference for each assumption was recorded in

the model spread sheet. The data used to set up the model is listed below.

Table 18: DSS Input Data

Data required Data Used Comments/Source

Current population served with

water 5,962

Lower Bellinger scheme water supply area

2011 permanent resident population was

estimated on the basis of total number of

accounts (2,484) at an occupancy ratio of

2.4.

Is the EP/ET expected to change in

the future? If yes how much (%) 0% HSc assumption

Population growth rate 0.5% Council’s advice (BSC email 27/4/12)

Current annual water supplied 1,052 ML 2011 total annual water production

climate corrected

Proportion of annual use

attributed to system losses (%) 12%

Based on BSC’s NSW Office of Water

report: 70 L/property/d (BSC email

27/4/12)

Current peak to average day

water demand ratio 1.0

Calculated from Climate Correction input

data average PDD and average day

demand 2005-2011

What change in baseline per

capita demands is expected over

the next 50 years? (%)

1% HSc assumption

Total length of water mains (rising

mains, trunk mains and

reticulation)

145 km BSC Water and Sewer Knowledge Centre

2010/2011 data


Data required Data Used Comments/Source

Number of accounts breakdown

Residential – 2,294

Commercial – 149

Other - 41

BSC Water and Sewer Knowledge Centre

2010/2011 data

Proportion of residential customers

with cooler (%) Estimated at 0% BSC staff

Assumed level of internal

residential water use per person

Estimated at 130

L/p/d

HSc assumption based on water

production data

Current annual water pumping

costs $166,700

All these do not include retic or trunk main

costs (source: BSC email 27/4/12)

Current annual water treatment

costs $ 243,100



Current sewage pumping costs $266,000 All these do not include retic or trunk main


Current annual sewage treatment

costs $ 646,800



Current volumetric charge per kL $1.60 BSC

Last year's volumetric charge $1.03 BSC

Capital works program for water

and sewerage

(30 years)

Water Supply

New reservoir in

Bellingen)- $2M

Sewerage

N/A

BSC

The DSS model requires the identification of four water demand management

scenarios. Each scenario is formed by combining different water demand

management measures. The scenarios are listed in Table 19. The water demand

management measures are based on pre-determined key assumptions underlying the

calculation of costs and benefits of conservation measures from the Best-Practice

Management Guidelines (2007) prepared by the NSW Office of Water.

Once all fields of the model were filled, a baseline demand and water saving of each

water demand management measure were calculated. The model then calculates

the average water saving (ML/a) and the Local Water Utility and Community

Benefit/Cost ratios of each demand management scenario chosen by Council staff.

The key outcomes of the model are the per capita demand, annual and peak day

demand forecasts for the Lower Bellinger water supply scheme. These scenarios and

their outcomes are listed in Table 19.


Outcomes

For each demand scenario the model provides projected average annual water

saving and associated community and LWU benefit/cost ratios figures. The average

annual water saving is an average of the 30 years water saving calculated by the

model. The water saving increase over the years due to growth and percentage of

customers take up. The benefit/cost ratio is the ratios of total benefits and costs arising

from a demand management effort. This means, the higher the ratios the better the

demand management measure benefit to the Lower Bellinger scheme. The definitions

of the community and LWU benefit/cost ratios are:

Community Benefit/ Cost Ratios: This is the ratios of the combined benefits and

costs of the utility and customers. This community perspective provides an

overall assessment of cost-effectiveness given that saving costs and saving

accrued by the utility are ultimately passed on to consumers through rates and

charges.

Utility Benefit/ Cost Ratios: This is the ratios of the benefits and costs from the

perspective of the local water utility. Costs include the cost of implementation

incurred by the water utility for planning, administration and education

campaigns and additional investment required by the utility, including water

loss management, recycled water and rainwater harvesting infrastructure.

These benefits and costs do not include the costs to customers of additional

investment in water efficient fixtures and appliances and source substitution, nor

benefits arising to customers from hot water saving.

The demand management scenarios developed by BSC staff and the DSS model

outputs for each scenario and for each individual water conservation measure are

provided in the following table.


Table 19: Water Demand Management Scenarios


Sce

nari

o 1

Sce

nari

o 2

Sce

nari

o 3

Sce

nari

o 4

Sta

nd

-alo

ne U

tili

ty

B/C

rati

o

Sta

nd

-alo

ne

Co

mm

un

ity B

/C r

ati

o

30

year

Avera

ge

Wate

r Savin

gs

ML/y

ear

National Mandatory Water Efficiency

Labelling Scheme (WELS) X X X X 8.4 0.7 7.8

Community Education Existing 1.3 2.3 13.2

Residential Shower Retrofit X X X X 7.6 21.1 0.8

Residential Washing Machine Rebate X X 42.7 0.7 12.3

Permanent Low Level Restrictions on

Water Use 3.9 3.9 29.3

Conservation Pricing for Residential Users X X X 120.1 120.2 57.4

Fixture Code - Taps and Showers - New

Development X X 4.5 5.8 10.4

Non-Residential Water Audits 28.1 26.6 10.1

System Water Loss Management Existing 0.1 0.1 6.0

Rainwater Tanks for all New Residential

Development 0.2 0.1 14.8

Dual Reticulation for all New Residential

Development 0.3 0.2 18.8

BASIX - Fixture Efficiency with Rainwater

Use X X 0.7 0.7 25.2

BASIX - Fixture Efficiency with Dual

Reticulation X 1.0 0.9 29.2

Evaporative Cooling Unit and Cooling

Tower Audit 0.0 0.0 1.7

Utility B/C Ratio 5.6 11.9 2.8 2.0

Community B/C Ratio: 1.5 2.6 0.9 0.9

Average Water Savings (ML/a): 18.3 75.4 99.6 123.8

Note: The water conservation measures description and the model assumptions to calculate their

water saving and benefit/cost ratio are provided in Table 20 below.


For each demand scenario, the DSS model provides a projected average annual

water savings and the associated community and LWU benefit/cost ratio figures. The

average annual water saving is an average of the 30 year water saving calculated by

the model. The water savings increase over the years due to growth and percentage

of customers take up. The benefit/cost ratio is the ratio of total benefits and costs arising

from a demand management effort. The higher the ratio the better the demand

management measure benefits the Lower Bellinger Water Supply Scheme.

The outcomes of these analyses provide a guide for selecting the preferred demand

management options to be implemented in BSC. Figure 25 shows that scenario 3 has

the second highest average water savings and a moderate benefit/cost ratio for both

the utility and the community. Based on the demand model outcomes, Scenario 3

appears to be the preferred scenario.

0

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40

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140

0.0

2.0

4.0

6.0

8.0

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14.0

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Ben

efit/

Cos

t Rat

io

Scenarios

Utility B/C Ratio Community B/C Ratio Average Water Savings (ML/a)

Figure 25: Water Demand Management Measures Scenarios Outputs

Based on this outcome the potential demand management measures for Bellingen

were selected.

Demand Management Options and Assumptions

The DSS model underlying assumptions regarding the costs and impacts of the different

demand management measures and scenarios is listed below.


Table 20: Demand Management Options and Assumptions

Description Assumed Market

Penetration Assumed Potable

Water Saving Assumed Implementation

Costs

Community Education

Council provides materials, training and technical assistance to implement a comprehensive on going communication program.

It is assumed that 20% of existing customers in each customer category are influenced by the community education effort.

On-going program. (Note: It is assumed that new customers are likely to be subject to BASIX)

Water saving vary dependent on the customer category and end use.

Expected savings from non-residential is 10%.

Costs to utility:

Set up (year 1): $10,000 plus 20 cents for each person in the supply area

Annual administration (from year 1): $3000 plus 5 cents for each person in the supply area

Permanent Low Level Restrictions on Water Use

The LWU would introduce a water waste regulation that would:

Prohibit irrigation during the times of the day with the highest evaporation

Mandate the use of a trigger nozzle when washing cars

Prohibit irrigation that fell on hard surfaces or hosing down of footpaths or driveways

It is assumed that 50% of all customers would adhere to the regulation.

On-going program

20% reduction in external use

The model assumes the following costs:

Setup (year 1): $10,000 plus 20 cents for each person in the supply area

Annual administration and enforcement (from year 1): $2000 plus 5 cents for each person in the supply area


Council would introduce an inclining block tariff for single family residential customers. The increase would result in an effective 50% increase in price for residential external use and no change in price for internal use.

All residential customers would be affected.

Price elasticity for external use is assumed to be -0.2 and for internal use is -0.05.

Expected reduction of:

2% from internal use

10% from external use

Cost to LWU:

Set up: $5,000 plus 20 cents for each person in the supply area





Costs

System Water Loss Management

Instead of more passive approaches where leaks are fixed when reported, councils would take a more active role by actually search for and repairing leaks in the supply system

One third of the system targeted each year for leak detection and repair.

Leak detection and repair assumed to be carried out over 10% of the system targeted.

Reduces leakage by 75% in targeted areas upon completion of work

Impact of leakage reduction effort will last 3 years

$280/km detection cost

$230/km repair cost

Program establishment costs (year 1): $5,000 plus 5 cents for each person in the supply area

Annual administration/ enforcement (from year 1): $2,000 plus 1 cent for each person in the supply area

Evaporative Cooling Unit and Cooling Tower Audit

This measures allows for water audits for evaporative cooling units and cooling towers

4% of existing residential, commercial and public customers participating each year

20% reduction Cost to LWU:


Annual administration/ enforcement (from year 1) - $1,000 plus 5 cents for each person in the supply area

Cost to community:

There is no cost to customer for the auditing.

Cost to customer for implementation of audit recommendations:

$100 for residential

$300 for non-residential





Costs

Non-Residential Water Audits

This measure is based on carrying water audits for non-residential customers.

It is assumed that 10% of non-residential customers would participate over a 3 year period.

The following saving are assumed:

10% saving in non-leakage consumption per customer.

75% reduction in customer leakage, with saving lasting five years.

Costs to utility:


Annual administration/ enforcement(from year 1): $1,000 plus 5 cents for each person in the supply area

Cost to community:

There is no cost to customer for the auditing. Cost to customer for implementation of audit recommendations: $300.


Upon request, a Council approved plumber would install a retrofit kit in existing single family residential housing.

It is assumed that 15% of existing residential customers would adopt this measure over a three year period.

For shower heads: based on average use volumes for each type of shower

5% of participants are free riders. (i.e. no extra cost for these 5% participants)

For taps: 20% reduction

For leakage: %5 reduction

Cost to utility: $30 per unit plus installation cost:

Water Miser: $50

Low flow: $20

Medium Flow: $10

Car Wash: $10





Costs


This option is based on a residential rebate to convert to efficient 4 star washing machines.

The model assumes that approximately 15% of residential customers would take up the washing machine rebate scheme over a three year period.

Based on average use volumes for each type of washing machine. 5% of participants are free riders (i.e. no extra cost for these 5% participants)

Cost per unit (approximately 52% is utility cost): Convert inefficient top loader to efficient top loader - $350 Convert inefficient top loader to front loader - $120 Convert inefficient top loader to efficient front loader - $350 Convert efficient top loader to front loader - $120 Convert efficient top loader to efficient front loader - $350 Convert front loader to efficient front loader - $350 Extra cost to community; Installation cost: Efficient front loader: $1000/unit Front loader: $900/unit Efficient top loader: $700/unit

Fixture Code - Taps and Showers - New Development (BASIX)

New development will install the kit which contains a low-flow shower head and a tap flow restrictor.

It is assumed that 90% of new residential customers would adopt this measure.

On-going program

For shower heads: Based on average use volumes for each type of shower, with 5% of participants in the program are free riders.

For taps: 20% reduction in Taps/Sink uses per account

For leakage: 5% reduction lasting for 5 years

Cost to utility:

Setup: $10,000 plus 20 cents for each person in the supply area;

Annual administration (from year 1): $3000 plus 5 cents for each person in the supply area

Cost to community:

For showerhead: $30/unit + installation cost: (water miser: $50; low flow: $20; medium flow:$10 and car wash:$10)

For Taps: $10/unit (assume 4 units per household) (100% cost to customer)





Costs

Rainwater Tanks for all New Residential Development

All new residential development would fit a rainwater tank. Rainwater to be supplied for toilet flushing, cold water to the washing machine and outdoor use.

100% of new residential customers

60% reduction for toilets and external use and 45% reduction for washing machine in targeted water uses under average conditions

Costs to utility: Setup: $10,000 plus 20 cents for each person in the supply area. Annual administration (from year 1): $3,000 plus 5 cents for each person in the supply area. Tank cost & installation: local rainwater tank cost (Utility and customer pay 50% of the installation cost). Cost to community: $30 per year per customer for operation

Dual Reticulation for all New Residential Development

All new subdivisions will be fitted with dual reticulation system with recycled water to be used for toilet flushing and irrigation

90% of all new residential developments (assume 10% are infill and therefore not suitable for supply with dual reticulation)

100% reduction in targeted end uses

Costs to utility: Setup: $10,000 plus 20 cents for each person in the supply area. Annual administration (from year 1): $3,000 plus 5 cents for each person in the supply area. Utility and customer pay 50% of the installation cost: $3,000 net per account for additional costs of dual reticulation

BASIX - Fixture Efficiency & Rainwater Tanks or Fixture Efficiency & Dual Reticulation

The NSW Government’s BASIX (Building Sustainability Index) program has been implemented throughout

NSW. In terms of impact on water demand, BASIX requires, as a minimum, all new dwellings to have

water efficient fittings and either a rainwater tank or access to recycled water (dual reticulation).

The assumptions used are a combination of the assumptions described above and listed below:

• Fixture Code – Taps and Showers and Rainwater Tanks for all New Residential Developments or

• Fixture Code – Taps and Showers and Dual Reticulation for all New Residential Developments





Costs


2005 saw the introduction of a mandatory Water Efficiency Labelling Scheme (WELS) for washing machines, shower, taps and dishwashers.

This measure assumes the following uptake:

efficient washing machines by 15% of customers over 3 years

low flow showerheads by 15% over 3 years

taps and dishwashers: 5% of new accounts and 1% of existing accounts

On-going program

The calculation is based on average use reductions of:

20% for taps

20% for dishwashers

30% for washing machines

30% for efficient showerheads

Costs to utility to enhance and promote scheme for three years:

Setup: $3000 plus 20 cents for each person in the supply area

Annual administration cost (from year 1 for 30 years): $500 plus 5 cents for each person in the supply area.

Utility also provides rebates to cover part of the cost of the washing machine:

same costs as per implementing Residential Washing Machines Rebate program


Appendix C

Rainwater Tank Assessment Input Data and Methodology


Introduction

This rainwater tank assessment has been prepared using the Rainwater Tank Model

provided by NSW Office of Water. The rainwater tank model calculates the benefits to

water usage and water bill savings per residential household. It assumes that a

rainwater tank provides potable water substitution. The model uses historical climate

data (from the last 20 years) to forecast the likely water savings under simulated

climate variability. This model provides a generic assessment of the benefits of

rainwater tanks as a source of water.

A rainwater tank analysis was undertaken for the Lower Bellinger water supply scheme,

as a representative location within the Shire; however it could be applied to other

localities in the Bellingen Shire.

Input Data and Assumptions

The input data is shown in the model calculation sheet provided below. The 20 years of

climate data is sourced from the Bureau of Meteorology SILO services. The climate

data was recorded in the vicinity of Bellingen town, at latitude and longitude 30.45°S

and 152.90°E respectively. Where no data was available, the typical (default) value of

the model has been used.

The local costs of rainwater tanks (see Table 21) were taken from quotations provided

by Bellingen local rainwater tank suppliers.

Council advised that the estimated current rainwater tanks take up in the Shire is

approximately 5% of the existing customers. This is an assumption made by Council

staff through observation; there is no study data on the actual number of rainwater

tanks currently used within the serviced area.

The annual average outside usage per household (526 L/d) was calculated from the

Bellingen town 2011 annual demand records. It is known that in 2011. Under the

conditions of large amount of rainfall, this would lead to the following considerations;

The existing rainwater tanks were expected to be full. Therefore reducing

potable water consumption.

External consumption would be expected to be reduced. In the long term the

526 L/d per household figure could be an under estimate.

The higher the outside usage the higher the benefits of installing rainwater tank

(in wet years). However during drought or periods of low rainfall it is likely that

the rainwater tanks won’t be full.


Input Data Sheet


Options Scenarios

The model allows for variability in water usage and tank size figures. The water usage

variability is used to determine the scenarios:

Scenario 1 - Outside usage only

Scenario 2 – Outside, toilets and washing machine

Each scenario has been assessed against three different tank sizes to determine their

yields and water bill savings.

Cost Analysis

For the purpose of these analyses it was assumed that the rainwater tank life was

10 years. The costs consist of rainwater tank and pump costs, including installation and

pipework installed in an existing development. The costs do not include delivery.

The criterion of selection for the tank analysis is the cost of water supplied from the tank

assessed against the tank yield. This calculation does not consider net present value

(NPV).

At the time of this assessment there were no Federal or State rainwater tanks rebates

available.

A summary of the Bellingen rainwater tank assessment outputs is shown in Table 21.

Table 21: Bellingen Rainwater Tank Assessment Outputs

Tank Size (kL)

Estimated Costs ($) Average Mains Water Savings (kL/year)

Average Rainwater Cost ($ / kL)

Scenario 1 – Outside usage only (tank costs only)

2 $ 1,195 68.4 $ 1.70

3 $ 1,125 83.1 $ 1.40

5 $ 1,950 103.0 $ 1.90

Scenario 2 – Outside, toilets and washing machine (cost include pump & pipework)

2 $2,150 80.4 $ 2.70

3 $ 2,080 95.1 $ 2.20

5 $ 2,905 116.5 $ 2.50

Mains Water Savings Analysis

The average yield of the rainwater tanks is the savings in mains water. These savings are

shown in Figure 26. The amount of potable water saved is not proportional to tank size

as can be seen from the graph. The graph shows that using tanks above 3 kL the mains

water savings (kL per year) were not as significant when assessed against costs.


30

40

50

60

70

80

90

100

110

120

130

1 2 3 4 5 6

Mai

ns W

ater

Savi

ngs (

KL/y

r)

Tank Size (KL)

Rainwater Tank Scenarios Comparison

Scenario 1 - Outside usage only

Scenario 2 - Outside, Toilet and WashingMachine (costs include pump & pipework)

Figure 26: Bellingen Rainwater Tank Assessment Scenario 1 & 2

The results of the rainwater tank assessment (see Table 21) show that scenario 2 is not as

financially attractive as scenario 1. The preferred option for this analysis is the 3 kL tank

of scenario 1 due to its moderate low rainwater costs per kilolitre and reasonable

rainwater tank yield when compared to the other options within scenario 1.

Using the preferred scenario outputs, an analysis of the percentage of total water

demand that may be supplied by rainwater tank according to number of connections

which take up on rainwater tanks has been undertaken. Four scenarios were prepared

based on the percentage of rainwater take up.

Scenario A: No additional rainwater tanks in existing properties. All new

dwellings will have rainwater tanks

Scenario B: 30% of residential properties in Lower Bellinger scheme supply area

will have rainwater tanks in 30 years

Scenario C: 60% of residential properties in Lower Bellinger scheme supply will

have rainwater tanks in 30 years

Scenario D: all residential properties in Lower Bellinger scheme supply will have

rainwater tanks in 30 years

The analyses assumed that householders will continue to use the rainwater tanks for 30

years and will replace them when required (this analyses assumes tank life of 10 years).


0%

10%

20%

30%

40%

50%

60%

70%

80%

% o

f Tot

al D

eman

d Su

pplie

d by

Rai

nwat

er Ta

nks

Year

Total Demand Supplied by Rainwater Tanks

A - 5%

B - 30%

C - 60%

D - 100%

% of take up in 30 years

Figure 27: Percentage of Total Demand Supplied by Rainwater Tanks

Outputs

The rainwater tank assessment outcome is summarised in Table 22.

Table 22: Water Demand (%) Supplied by Rainwater Tanks

Rainwater Tanks Take Up Rates (in 30 years)

% of Total Demand Supplied by Rainwater Tanks (In 30 years)

5% 13.2

30% 29.1

60% 48.3

100% 73.9

Discussion and Recommendation

If BSC adopts rainwater tanks as an option to reduce annual and peak day demand, a

3 kL tank would be recommended as the optimal size. If the existing take up rate

remains the same and all new developments continue installing rainwater tanks, the

potable water saving in 30 years would be approximately 13.2%. However if the take up

rate increases the water saving benefit will be even higher.

If rainwater is to be used for outside use only (scenario 1) the water cost would be

higher than the water usage charge of $1.60/kL (for the first 365 kL/year in 2010/11).

Rainwater cost for the preferred option is $1.40/kL. Rebates are no longer available to

cover the tank costs.


Should Council consider the water savings of the preferred scenario an advantage for

the water supply scheme, Council may consider providing extra support to the

households to ensure the rainwater tank take up rate remains the same or increase.

Such extra support may include:

Provide rebates

Identifying other rainwater tank suppliers in the area which could provide a

competitive price

Promoting the installation and use of rainwater tanks

Based on the CSIRO report (see section 4.1), the change in rainfall will affect the yield

of rainwater tanks. This will impact the output of the analysis.

Based in Sydney and Byron Bay, HydroScience Consulting (HSc) is an Australian consultancy

dedicated to serving the water industry in Australia.

HSc provides planning and design services to public and private sector clients throughout Australia.

We are committed to developing strong client relationships that become the foundation for

understanding our clients’ needs and exceeding their expectations.

Byron Bay

Unit 6

64 Centennial Circuit

Byron Bay, NSW, 2481

Tel: 02 6639 5600

Fax: 02 6680 9319

Sydney

Level 1

189 Kent Street

Sydney, NSW, 2000

Tel: 02 9249 5100

Fax: 02 9251 4011

Email: [email protected]

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