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Welsh GovernmentM4 Corridor around NewportEnvironmental Statement Volume 3: Appendix 2.1 Operational Traffic Data (Extract From Traffic Forecasting Report)

M4CaN-DJV-EGN-ZG_GEN-AX-EN-0014

At Issue | March 2016

CVJV/AAR 3rd Floor Longross Court, 47 Newport Road, Cardiff CF24 0AD

Welsh Government M4 Corridor around NewportTraffic Forecasting Report

M4CaN-DJV-HTR-ZG_GEN-RP-TR-0001 | March 2016

Page 59

Figure 9.1: Base Year Peak Hour Traffic Flows



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Figure 9.2: Base Year Annual Average Daily Traffic Flows



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Figure 9.3: 2022 Forecast AM Peak Hour Traffic Flows, Core Scenario



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Figure 9.4: 2022 Forecast Inter-peak Hour Traffic Flows, Core Scenario



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Figure 9.5: 2022 Forecast PM Peak Hour Traffic Flows, Core Scenario



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Figure 9.6: 2022 Forecast Annual Average Daily Traffic Flows, Core Scenario



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Figure 9.7: 2037 Forecast AM Peak Hour Traffic Flows, Core Scenario



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Figure 9.8: 2037 Forecast Inter-Peak Hour Traffic Flows, Core Scenario



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Figure 9.9: 2037 Forecast PM Peak Hour Traffic Flows, Core Scenario



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Figure 9.10: 2037 Forecast Annual Average Daily Traffic Flows, Core Scenario

Welsh GovernmentM4 Corridor around Newport Environmental Statement Volume 3: Appendix 2.2 Drainage Strategy Report

M4CaN-DJV-HDG-ZG_GEN-RP-CD-0001



Welsh Government M4 Corridor around Newport

Drainage Strategy Report

Contents

Page

1 The Project 1

2 Scope of this Report 3

3 Basis of Assessment 4

4 Carriageway Drainage, Basic Spillage Control and Water Treatment 4

5 Median Drainage 10

6 Attenuation Lagoons and Embankment Height (Across the Gwent Levels) 10

7 Cross Flow Culverts 11

8 Embankment Toe/Reen Drainage 14

9 River Usk crossing drainage 14

Appendices

Appendix A

Figure 2 – Water Treatment Area layout



M4CaN-DJV-HDG-ZG_GEN-RP-CD-0001 | March 2016 |

Page 1

1 The Project

1.1 Context

1.1.1 The Welsh Government has awarded a Professional Services Contract for the next stage of Scheme development and environmental surveys for the M4

Corridor around Newport (M4CAN) up to publication of draft Orders and an

Environmental Statement. The contract has been awarded to a Joint Venture of

Costain, Vinci and Taylor Woodrow with consultants Arup and Atkins, supported

by sub-consultant RPS. The team shall be developing proposals in anticipation

of publishing draft Orders and an Environmental Statement in spring 2016 and a

Public Local Inquiry later that year. This process will then inform the next stage of

Ministerial decision making.

1.1.2 Since 1989 there have been various studies to identify the problems and propose possible solutions. The M4 Corridor around Newport WelTAG Stage 1 (Strategy

Level) Appraisal concluded that a new section of 3-lane motorway to the south of

Newport following a protected (TR111) route, in addition to complementary

measures, would best achieve the goals and address the problems of the M4

Corridor around Newport and should be progressed for further appraisal. These

options have subsequently formed the basis for the development of the draft

Plan, which was published in September 2013 and was the subject of public

consultation from September to December 2013.

1.1.3 Having taken into account the responses to this participation process, as well as the assessments of the draft Plan, the Welsh Government has decided to publish

a Plan for the M4 Corridor around Newport. Alongside this Plan, the Welsh

Government has published updated strategy-level reports, including a Strategic

Environmental Assessment Statement, to demonstrate how the participation

process has informed its decision making. It also announced in July 2014 a

revised preferred route, which will protect a corridor for planning purposes.

These documents can be accessed from the website http://m4newport.com.

1.2 Scheme objectives and reason for the scheme

1.2.1 The aims of the Welsh Government for the M4 Corridor around Newport are to:

a) Make it easier and safer for people to access their homes, workplaces and

services by walking, cycling, public transport or road.

b) Deliver a more efficient and sustainable transport network supporting and

encouraging long-term prosperity in the region, across Wales, and enabling

access to international markets.

c) To produce positive effects overall on people and the environment, making a

positive contribution to the over-arching Welsh Government goals to reduce

greenhouse gas emissions and to making Wales more resilient to the effects

of climate change.

1.2.2 The Scheme aims to help to achieve or facilitate these aims as part of a wider transport strategy for South East Wales, as outlined within the Prioritised National

Transport Plan.




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1.2.3 The Transport Planning Objectives (TPOs), or goals, are:

TPO 1: Safer, easier and more reliable travel east-west in South Wales.

TPO 2: Improved transport connections within Wales and to England, the Republic of Ireland and the rest of Europe on all modes on the international transport network.

TPO 3: More effective and integrated use of alternatives to the M4, including other parts of the transport network and other modes of transport for local and strategic journeys around Newport.

TPO 4: Best possible use of the existing M4, local road network and other transport networks.

TPO 5: More reliable journey times along the M4 Corridor.

TPO 6: Increased level of choice for all people making journeys within the transport Corridor by all modes between Magor and Castleton, commensurate with demand for alternatives.

TPO 7: Improved safety on the M4 Corridor between Magor and Castleton.

TPO 8: Improved air quality in areas next to the M4 around Newport.

TPO 9: Reduced disturbance to people from high noise levels, from all transport modes and traffic within the M4 Corridor.

TPO 10: Reduced greenhouse gas emissions per vehicle and/or person kilometre.

TPO 11: Improved travel experience into South Wales along the M4 Corridor.

TPO 12: An M4 attractive for strategic journeys that discourages local traffic use.

TPO 13: Improved traffic management in and around Newport on the M4 Corridor.

TPO 14: Easier access to local key services and residential and commercial centres.

TPO 15: A cultural shift in travel behaviour towards more sustainable choices.

1.2.4 The scheme-specific environmental objectives (EO), as set out in the Strategic Environmental Assessment of the Plan, are as follows:

EO1 - Improved air quality in areas next to the existing M4 around Newport;

EO2a - Reduce greenhouse gas emissions per vehicle and/or person kilometre;

EO2b - Ensure that effective adaptation measures to climate change are in place;

EO3 - Reduce disturbance to people from high noise levels, from all transport modes and traffic within the existing M4 Corridor;




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EO4 - Ensure that biodiversity is protected, valued and enhanced;

EO5 - Improved access to all services and facilities and reduce severance;

EO6 - Protect and promote everyone’s physical and mental wellbeing and safety;

EO7 - Reduce transport related contamination and safeguard soil function, quality and quantity;

EO8 - Minimise transport related effects on surface and groundwater quality, flood plains and areas of flood risk;

EO9 - Ensure the prudent and sustainable use of natural resources and energy;

EO10 - Ensure that diversity, local distinctiveness and cultural heritage are valued, protected, celebrated and enhanced;

EO11 - Ensure that landscape and townscape is properly valued, conserved and enhanced;

1.2.5 In addition, the Wales Transport Strategy includes the following environmental outcomes (WTSEO):

Outcome 11: The sustainability of the transport infrastructure - Increase the use

of more sustainable materials in our country’s transport assets and infrastructure;

Outcome 12: Greenhouse gas emissions - Reduce the impact of transport on greenhouse gas emissions;

Outcome 13: Adapting to climate change - Adapt to the impacts of climate change;

Outcome 14: Air pollution and other harmful emissions - Reduce the contribution of transport to air pollution and other harmful emissions;

Outcome 15: The local environment - Improve the positive impact of transport on the local environment;

Outcome 16: Our heritage - Improve the effect of transport on our heritage;

Outcome 17: Biodiversity - Improve the impact of transport on biodiversity.

2 Scope of this Report

2.1.1 The scope of this report is the drainage strategy for the proposed highway.

2.1.2 This report informs how the Scheme would deliver principally on the following Scheme objectives: Transport Planning Objectives 1 and 7; Environmental

Objectives Wales 2b, 4 and 8, Transport Strategy Environmental Outcomes 13

and 17.




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3 Basis of Assessment

3.1.1 Following consultations and reviews undertaken previously, a set of design criteria for the drainage design has been developed which aims to promote

sustainable drainage and meet the requirements of Natural Resources Wales

(NRW), South Wales Trunk Road Agency (SWTRA) and the Design Manual for

Roads and Bridges (DMRB) guidelines. These reflect the unique hydrological

environment of the Gwent Levels, through which the M4 Corridor around Newport

would pass.

3.1.2 Consultation is currently being held with NRW and SWTRA, and the drainage strategy is subject to their approval.

4 Carriageway Drainage, Basic Spillage Control and Water Treatment

4.1.1 For the majority of its length, the proposed Scheme is located within the Gwent Levels. Typical ground conditions comprise very soft sub-soils with a very high

water table. In order to minimise settlement, impact upon the ground water level

and visual intrusion, it is proposed to maintain a low level embankment on which

the new section of motorway is constructed. Discharge to lined drainage

channels will be adopted because a conventional gulley and pipe drainage

system would require longitudinal falls which could only be created by raising the

embankment.

4.1.2 In addition, the adopted strategy requires the surface water run-off, after attenuation and treatment, to discharge to the major NRW reens where there is a

greater flow of water. This will either be directly by pipe or by the addition of

engineered field ditches, which would discharge to the main reens.

4.1.3 It is proposed to intercept the run-off from the new section of motorway into grassed channels in the verge. These are trapezoidal shaped are typically 2.1m

wide, widening to 3.0m wide x 0.8m deep near outfall points. Side slopes would

be 1 in 1.5. These route surface water overland from the drained carriageway to

the water treatment areas. When the carriageway is super elevated in the central

reserve of the motorway, the introduction of concrete barriers and maintenance

restrictions excludes the use of grassed channels. Here concrete channels will be

utilised.

4.1.4 The grassed channels will be dry during dry weather, enhancing their pollutant removal capability, but during a rainfall event the water will flow into them from

the carriageway and move slowly to the outfall point. The flow of water will be

retarded and filtered by the grass. Sediment will be deposited and oily residues

and organic matter retained and broken down in the top layer of soil and

vegetation. During a rainfall event, a proportion of the run-off may be lost due to

evaporation and transpiration. The use of grassed channels has been identified

as a means of reducing pollution and promoting a more sustainable drainage

system compared to conventional drainage systems.

4.1.5 The grassed channels will follow the gradient of the new section of motorway, typically 1 in 7,000 through the Levels. It is anticipated that they would be lined

with a geo-synthetic clay liner below 50mm of topsoil. This eliminates the risk of




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surface water run-off containing possible pollutants seeping into the underlying

ground.

4.1.6 The very flat longitudinal gradients across the Gwent Levels would exclude the use of kerb and gully and a piped drainage system because the longitudinal falls

necessary for this system could not be achieved in an efficient way.

4.1.7 SWTRA have proposed that they would maintain the grassed channels using self-propelled or remote control mowers. These would require cutting 3 times a

year in late spring and summer. Grass length should not be longer than 75mm, in

accordance with DMRB HA 119/06.

4.1.8 The grassed channels within the SSSI are currently proposed to cater for a 1 in 100 year storm event with allowance for climate change. Substantial storms in

excess of this return period event would overflow over the highway embankment

into the adjacent field reens, but it is considered that a storm intensity of this

magnitude would dilute any pollutants to acceptable levels, and that the statistical

probability of the storm occurring is very low. A typical section of the road across

the Levels is shown in Figure 1 overleaf.




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Figure 1: Typical section of highway across the Gwent Levels




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4.1.9 The run-off in the grassed channels will be captured in collection sumps and routed to the water treatment areas, see Figure 2 (in

Appendix A).

4.1.10 From the sumps the water would flow into the water treatment and attenuation areas. They will include the provision to capture

hydrocarbons and grits prior to flows entering the main attenuation

lagoons.

4.1.11 Where the highway alignment dictates that steeper falls are introduced or the carriageway drains to the median, conventional

drainage will be used, typically concrete surface water channels.

4.1.12 All drainage from the new section of motorway will be designed to capture run-off from the carriageway for all events up to the 1% (1 in

100 year) AEP rainfall event with the addition of a 30% allowance for

climate change.

4.1.13 With the exception of discharges to the River Usk and the River Ebbw, all drainage will be treated through 15 Water Treatment Areas.

These areas are listed below in Table 1.

4.1.14 When flows enter the WTA they first pass through a forebay area before entering the main attenuation lagoon. The forebay contains

systems which are designed to retain a minimum of 50 cubic metres

of oil/hydrocarbon.

4.1.15 The main attenuation lagoon has been designed to restrict flow to the equivalent ‘greenfield runoff’ within the Gwent Levels. The

attenuated flow from the lagoon is trickle fed through a reed bed for

final polishing and treatment before discharging into either

replacement reens or the main reen system.

4.1.16 Water quality at the outfalls from the water treatment areas will be of a quality and quantity to enable these parts of the drainage system to

support the SSSI features. Further details of the water quality strategy

for the Scheme are provided in the Environmental Statement

Appendix 16.3.

4.1.17 For outfalls to the River Usk and River Ebbw, there is no requirement for flow attenuation as the flows outfall to a tidal river. Pollution control

will be provided by oil separators. These will be either baffle

arrangements within open lagoons or within bespoke underground

units.

4.1.18 For side roads where there is no increase in impermeable area, existing outfalls will be utilised.

4.1.19 For side roads where impermeable areas are increased and new junctions, outfalls will include pollution protection using oil separators

and attenuation lagoons. These outfalls are outlined below in Table 2.




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Table 1: Outfall Details

Outfall no.

Receiving Watercourse

Estimated Highway runoff storage volume

required (m3)

Attenuated Discharge

rate

(l/s)

Contributing Impermeable

Area

(Ha)

1 Pwll Bargoed Reen

9000 32.5 9.3

2 Tyn-y-Brwyn Reen

10500 40.1 11.5

3 Outfall to Newport County Council (NCC) drainage network without attenuation (Existing or modified side roads only). No motorway drainage to be discharged to the NCC system and overall contributing areas will be reduced.

4a Percoed Branch East

4200 15 4.3

4b Percoed Branch East

4200 15 4.2

5 Morfa Gronw Reen

7000 25.6 7.3

6 Lakes Reen 4000 16.8 4.8

7 Julians Reen 3600 14.4 4.1

8 Ellen Reen 8400 31.5 9

8a Black Wall Reen

3500 3.5 1

9 Middle Road Reen Diversion

13000 55.3 15.8

10 Rush Wall South Reen

2700 11.6 3.3

11b St Bride’s Brook

7950

17.7 6

11c St Bride’s Brook

5100 17.6 5

12a Prat Reen 18000

50.5 14.4

12b Vurlong Reen

675 2.6 0.73




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Table 2 – Side Roads and Main river outfalls

4.1.20 Fin drains will be installed along the edge of carriageway between the edge of pavement and the safety barriers. These will run for 200m

before discharging into a 1050mm dia type 7 catchpit which outfalls

into the replacement reen or field ditch at the toe of the embankment

or to the granular drainage blanket below the road formation.

Receiving Watercourse

Estimated Highway runoff storage

volume required (m3)

Attenuated Discharge

rate

(l/s)

Contributing Impermeable

Area

(Ha)

Ebbw West Outfall N/A N/A 1.3

Ebbw East Outfall (inc. SDR link)

N/A N/A 11

Usk Outfall N/A N/A 2.9

Meadows Road North 350 1.2 0.34

Meadows Road South

350 1.2 0.34

North Row North 350 1.1 0.31

North Row South 350 1.2 0.34




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5 Median Drainage

5.1.1 Over some stretches of the new section of motorway, the road will be super elevated and drainage to the median channel is required. The

central reserve will be hardstanding, with a concrete vertical concrete

barrier, and as described earlier, a concrete channel is used.

5.1.2 The size of the channel is limited by the amount of space available in the central reserve. Generally this is 1.5m, however as a result of

widening for visibility on some curved sections the size may vary.

The depth of the channel is limited to 0.15m as this is the largest

allowable depth which is not required to have a barrier between the

channel and the road edge.

6 Attenuation Lagoons and Embankment Height (Across the Gwent Levels)

6.1.1 Each attenuation lagoon is designed to cater for a 1 in 100 year storm event with an allowance for climate change. Historically, the

greenfield runoff rate has been restricted to 3.5l/s/Ha as set by the

NRW. During meetings during Key Stage 3, NRW have stated that

this value is appropriate for the design.

6.1.2 In order to minimise the height of the motorway embankment, the flood storage variation in the lagoons is generally limited at 1.1m, with

a minimum of 0.2m freeboard above this. The outfalls from the

lagoons discharge into a reen at or above the Summer Penning Level

(SPL). The SPL for each reen is set by the NRW and is unique to

each reen. Although the water level in the reens can rise occasionally

above the summer penning levels, a flap valve at the outfall pipe will

ensure that the water from the reen does not flow into the lagoon.

6.1.3 The height of the highway embankment is dependent on the following factors at each outfall:

• Crossfall in Carriageway

• Depth of grassed channels/concrete channel

• Cover depth to pipe crossing carriageway

• Pipe diameter to the water treatment area

• Fall due to pipe gradient, grit trap, petrol interceptor, spillage

lagoon, reed beds.

• Attenuation depth in lagoon

• Summer penning level in the reen

6.1.4 Based on these factors, the minimum embankment height across the Levels will be some 2.1m above the SPL.

6.1.5 It is anticipated that fencing would be provided to each water treatment area to prevent/restrict access to the ponds and lagoons.




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Typical layout of the water treatment areas is shown in Figure 2, see

Appendix A.

7 Cross Flow Culverts

7.1.1 The culverts beneath the proposed motorway embankment with discernible catchments will be designed to cater for the 1 in 100 year

storm events including climate change allowance. In all, assessment

of the reen system indicates that a total of 37 culverts are required

across the levels to culvert the major reens. Details of the primary

culverts are shown in Table 3. Bed levels are subject to the results of

detailed survey, which could increase the culvert sizes to allow

sufficient freeboard.

Table 3 Culvert details

Structure No.

Culverted

Watercourse

Bed Level (m

AOD)

WPL

(m AOD)

SPL

(m AOD)

Chainage Nearest Structure

SMN 0510

Nant-y-Moor Reen (extension of existing)

3.71 4.25 4.7 5+100 W56

SMN 0550

SDR Reen Culvert

4.31 4.65 5 5+500 W50

SBR 0570 Percoed Reen 4.31 4.65 5 5+850 W50

SMN 0680

Morfa Gronw Reen

3.9 5.55 5.55 6+900 W69

SMN 0770

Old Dairy Reen Field Access Culvert

4.1 5.77 5.82 7+700 W73

SMN 0775

Old Dairy Reen

4.1 5.77 5.82 7+750 W73

SMN 0800

Pont-y-Cwcw

Reen

4.8 5.70 6.00 7+990 W81

SMN 0805

Replacement Reen Pont-y-Cwcw

4.8 5.7 6.000 8+050 W81

SBR 0835 Sea Wall Reen TBC TBC TBC 8+380 N/A

SMN 0905

Maes-Glas Pill TBC TBC TBC 9+050 N/A

SMN 1180

Picked Lane Culvert

TBC TBC TBC 11+800 N/A

SMN 1230

Lakes Reen 3.895 4.70 5.30 12+350 C01

SMN 1235

Lake's Reen North Access Culvert

3.895 4.70 5.30 12+350 C01

SMN 1240

Julian's Reen Side Road

3.895 4.70 5.30 12+450 C01




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Structure No.

Culverted

Watercourse

Bed Level (m

AOD)

WPL

(m AOD)

SPL

(m AOD)


SMN 1250

Julian's Reen Farm Access Culvert

3.895 4.70 5.30 12+500 C01

SMN 1300

Julian’s Reen 3.895 4.70 5.30 13+000 C01

SMN 1305

Tatton Farm Access

3.895 4.7 5.30 13+050 C01

SMN 1310

Julian’s Reen Access Track Culvert

3.895 4.7 5.30 13+050 C01

SMN 1330

Tatton Farm Culvert

4.00 4.23 4.5 13+300 N/A

SMN 1350

Field Culvert 4.00 4.23 4.5 13+550 N/A

SMN 1430

Ellen Reen 3.61 4.23 4.5 13+900 C23

SMN 1445

Ellen Reen Diversion Track Culvert

3.61 4.23 4.5 14+400 C23

SMN 1475

Glan Llyn Link SAR Ditch


SMN 1480

Black Wall Reen

3.50 4.23 4.50 14+890 C23

SBR 1480 Monk’s Ditch 4.35 4.00 5.30 14+900 N/A

SBR 1640 Steelworks Dedicated Reen

1.25 - - 15+750 N/A

SMN 1655

Elver Pill Reen 3.785 4.26 4.5 16+650 C35

SMN 1720

New Cut Reen 2.965 4.1 4.45 17+200 C62

SMN 1750

North Row SAR Ditch Culvert


SBR 1755 North Row Middle Road Reen (North)

2.965 4.1 4.45 17+550 C62

SBR 1770 North Row Middle Road Diversion Reen (South)

2.965 4.1 4.45 17+800 C62

SBR 1780 Mainline Middle Road Diversion Reen

2.965 4.1 4.45 17+900 C62

SMN 1850

Cock Street Reen

3.00 3.60 4.30 19+250 N/A




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Structure No.

Culverted

Watercourse

Bed Level (m

AOD)

WPL

(m AOD)

SPL

(m AOD)


SMN 1925

Petty Reen 3.00 3.60 4.30 19+250 N/A

SMN 1940

Rush Wall Reen Culvert

3.00 3.60 4.30 19+275 N/A

SMN 1970

Bareland Street East North Culvert


SMN 1980

Bareland Street East South Culvert


7.1.2 The majority of the reens to be culverted have only a small catchment and a box culvert, sufficient to cater for the flows and provide

sufficient head room for maintenance will be provided.

7.1.3 The culverts will be sufficiently large to allow man entry for maintenance purposes. The culverts are to be designed to allow the

invert level to be placed at a minimum of 150mm below the bed level

of the reens being culverted. In addition, a minimum of 200mm free

board is allowed above the summer penning level of the reens.

Mammal crossings will be provided independently to the hydraulic

culverts. The mammal crossings will be 900mm dia pipes which will

be positioned with the invert above the SPL.

7.1.4 In addition to the primary culverts, a number of secondary culverts will be required. These include culverts for access tracks for water

treatment areas, culverts to take runoff from cut off ditches, and to

allow connectivity of field ditches. These have not been included in

the list above as details of these will be developed during detailed

design. They will be Category 0 structures.

7.1.5 The crossflow culverts are generally located perpendicular to the motorway, permitting the shortest length of culvert. This also allows

the existing flows in the reens to be maintained while the culvert is

constructed off-line.

7.1.6 The culverts consist of pre-cast concrete sections, generally 2.0m in length. They will either be piled or will be constructed on a granular

bed which has been laid on the alluvium beneath. A geotextile

membrane ensures that the granular bed does not penetrate the

alluvium. The ground will be surcharged prior to the culvert being

constructed in order to minimise movement in the culvert sections

once construction is complete.

7.1.7 In-situ or precast concrete headwalls are constructed at each end of the culvert and the reens diverted into the culverts. The construction

of the culverts and headwalls off-line will minimise the disruption to

the reens. Penstock valves will be included on the end of each

headwall to enable the culvert to be isolated for maintenance access.




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8 Embankment Toe/Reen Drainage

8.1.1 Reens are generally provided on the north side of the new section of motorway to provide improved connectivity with the cross flow

culverts. NRW recommended that these reens are excavated to a

depth of 2.0m with 1 in 1 side slopes, a 0.7m berm and are

approximately 5.7m wide at the surface. The total length of

replacement reens and field ditches will be equal or greater than the

reens and field ditches to be infilled.

8.1.2 On the south side, smaller field ditches will be used to connect the existing field ditches to the nearest main reens. NRW recommended

that these are 2.5m wide with 1 in 1 slopes and 1m deep.

8.1.3 It is proposed to provide means of regulating flows at the head and outflow of the cross flow culverts. This would allow the regulation of

water level and flow along the entire length of the motorway corridor.

In addition, the sluices can be utilised when maintaining the reens

and culverts by diverting flows from one catchment to another. This

arrangement will provide maximum flexibility in supplying water

across the Gwent Levels.

8.1.4 Further detailed information on the reen proposals is provided in the Reen Mitigation Strategy file note (M4CaN-DJV-HDG-ZG_GEN-FN-

CD-0002).

9 River Usk crossing drainage

9.1.1 The drainage on the River Usk crossing will consist of kerb drainage out falling to a pipe that runs along the central reservation. Kerb

drainage will be present on the central reservation and the westbound

carriageway, as the deck is super elevated along its length. The

diameter of the pipe varies along its length, reaching a maximum

internal diameter of 750mm. Connections from kerb drainage in the

westbound carriageway will occur at 100m intervals.

9.1.2 On the west side of the River Usk crossing, drainage will discharge into the River Ebbw via an oil separator. An attenuation lagoon will

not be required as the River Ebbw is tidal at this point, and is not

impacted by additional fluvial flows.

9.1.3 On the east side of the River Usk the drainage will outfall into the River Usk via a small storage lagoon and a field ditch. The lagoon is

provided to store surface water run-off during periods when the outfall

is surcharged by tide levels in the estuary. The pond also has the

ability to retain hydrocarbon spillages using baffle plates at the outfall.

Appendix A

Figure 2 – Water Treatment Area layout




Page A1

A1 Figure 2

Legend

Welsh GovernmentM4 Corridor around Newport Environmental Statement Volume 3:Appendix 2.3 Reen Mitigation Strategy

M4CaN-DJV-HDG_GEN-FN-CD-0002



File Note

Page 1 of 9

Project title M4 Corridor around Newport

cc File reference

M4CaN-DJV-HDG_GEN-FN-CD-0002

Prepared by

Date

March 2016

Subject i

Reen Mitigation Strategy

1. Introduction

The purpose of this note is to outline the reen mitigation strategy for the section of the proposed M4.

The Scheme is a new section of 3-lane motorway to the south of Newport following a protected (TR111)

route. Part of this route crosses the Gwent Levels. These Levels contain a large number of Natural

Resources Wales (NRW) maintained watercourses. These watercourses will be referred to as “reens” for the

remainder of this report. Between these reens there are also a significant amount of smaller drainage ditches

around or within fields which do not necessarily take water all year round, and have a base level above that

of the surrounding reens. These will be referred to as “field ditches”. These are maintained by the

landowners/tenants.

As the proposed new section of motorway crosses the Levels, it bisects a number of reens and field ditches.

This note covers the proposals for mitigation measures to minimise watercourse and environmental impacts

for the removal of these reens and field ditches.

Consultation has been undertaken with NRW with regards to the proposals, but approval of the proposals is

still required.

2. The Existing Reen Network

The current reen system on the Gwent Levels is a network of interconnecting watercourses (reens and field

ditches) which feed into the Severn Estuary. As the area is below high tide the reens serve as a storage

facility when outfalls are tide locked. The water levels in the reens are controlled by a series of sluice

structures. NRW have the responsibility for the reen management and maintenance for the watercourses

classified as Main Rivers (generally running north to south) and also all other major reens within the Caldicot

and Wentlooge Levels Internal Drainage District. These two types of reen are subject to differing

maintenance regimes which are currently under review. Further information on the reen system is provided in

“The Caldicot & Wentlooge Levels Drainage Board Its History, Functions and Water Level Management

Plan” (July 1995).

The water levels in the reens are divided into Winter Penning Levels (WPL) and Summer Penning Level

(SPL). WPL is the water level in the reen during winter, which is kept lower to provide additional storage

capacity. SPL is the water level during summer, which is kept higher to provide a water source for

agricultural purposes. During extreme storm events it is possible for water levels to rise above these levels.

NRW review the WPL and SPL on a five year cycle taking into account landowner considerations. A review

of these penning levels has confirmed that the WPL and SPL will not change in the vicinity of the proposed

scheme.

File Note

March 2016

Page 2 of 9

Reens typically have 1 in 1 side slopes, and vary in depth and width, typically 3m width at the top and 1m at

the base. As the water levels are controlled by sluices there is typically very little flow, and most of the reens

have no recognisable catchment within the Flood Estimation Handbook (FEH) software.

Field ditches are smaller than these reens and are frequently dry. They commonly run along existing

hedgerows on the edge of fields and connect to the reens.

The reens and ditches support a wide range of aquatic plants, including many rare or scarce species that in

turn support a wide variety of other wildlife. There is a diverse community of insects (for example water

beetles) and other invertebrates inhabiting the reens and ditches. The assemblage of water beetles found

across the Levels is unique in Wales and includes the great silver water beetle which is found nowhere else

in Wales and is restricted to only a few other sites in southern England. This is the reason that the Levels

have been designated a Site of Special Scientific Interest (SSSI).

The un-mown ditch banks and rough grassland areas provide habitat for the shrill carder bee, as they

contain the flowers preferred by the bee for sources of nectar and pollen, such as red clover, creeping thistle

and black knapweed.

The reens and ditches also provide habitat for protected species including otter, water vole, grass snake and

amphibians.

3. Scheme Impact on Existing Reens and Field Ditches

The Scheme crosses reens and field ditches at a series of locations (see Appendix A). These reens and field

ditches would be infilled as part of the scheme. The estimated length of reens that would be infilled and

culverted as part of the Scheme is approximately 2,570m. The estimated length of field ditch crossings that

would be infilled as part of the Scheme is approximately 9,150m.

Table 1 (below) breaks down the infilled reens across the scheme.

Chainage Reen Name Length infilled

Reason infilled

5+100-5+300 Nant-y-moor Reen

194m Existing reen runs parallel and underneath mainline footprint

5+500-5+750 Percoed Reen and SDR reen

274m Existing reen runs underneath mainline footprint, with junction with SDR reen

6+820-6+900 Morfa Gronw Reen

116m Existing reen runs perpendicular to mainline footprint

7+750 Old Dairy Reen 79m Existing reen runs perpendicular to mainline footprint

7+980 Pont-y-Cwcw 74m Existing reen runs perpendicular to mainline footprint

8+400 Sea Wall Reen 267m Existing reen diverted away from Sea Wall to allow construction of bridge abutment over River Ebbw

12+350 Lakes Reen 53m Existing reen runs perpendicular to mainline footprint

12+400 Julians Reen 89m Existing reen runs parallel to existing side road

13+000 Julians Reen 55m Existing reen runs perpendicular to mainline footprint

File Note

March 2016

Page 3 of 9

Chainage Reen Name Length infilled

Reason infilled

14+280 – 14+360

Ellen Reen 210m Existing reen runs perpendicular to mainline and slip road footprint

14+650-14+750 Middle Reen 163m Existing reen runs perpendicular to mainline and slip road footprint

14+880 Black Wall Reen 112m Existing reen runs perpendicular to mainline and slip road footprint

14+900 Monks Ditch 103m Existing reen runs perpendicular to mainline and slip road footprint

16+600 Elver Pill Reen 65m Existing reen runs perpendicular to mainline footprint

17+750 Middle Road Reen Diversion

41m Existing reen runs underneath North Row side road at skew

17+900 Middle Road Reen Diversion


18+480 Cock Street Reen 60m Existing reen runs perpendicular to mainline footprint

19+150 – 19+410

Petty Reen 198m Existing reen runs perpendicular to mainline footprint

19+650 – 19+750

Stutwall Reen 142m Existing reen runs perpendicular to mainline footprint

19+850 – 20+050

Bareland Street Reen


Total 2568m

Table 2 (below) breaks down the infilled field ditches across the Scheme.

Chainage Length infilled

Reason infilled

5+630 – 5+950 376m Existing field ditch under mainline footprint and Percoed NMU bridge approach embankment

5+950 – 6+050 109m Existing field ditch under footprint of WTA 4a

6+050 – 6+100 383m Two existing field ditches under footprint of WTA 4a and mainline

6+120 – 6+280 170m Existing field ditch under mainline footprint


6+400 – 6+550 419m Existing field ditch under mainline and structural embankment footprint


6+900 66m Existing field ditch under mainline footprint connecting to Morfa Gronw Reen

6+930 – 7+400 718m Existing field ditches parallel to mainline footprint and WTA 5.

7+380 106m Existing field ditch parallel to Lighthouse Road Side Road

7+410 61m Existing field ditch under mainline footprint

7+500 99m Existing field ditches under mainline footprint

7+520 – 7+670 184m Existing field ditch parallel to mainline footprint

File Note

March 2016

Page 4 of 9


Reason infilled


7+730 68m Existing field ditch perpendicular to mainline footprint


8+000 – 8+350 421m Existing field ditches under embankment approach to River Ebbw Crossing

11+550 67m Existing field ditches under embankment from main bridge crossing


11+800 – 12+000 313m Existing field ditches under mainline footprint


12+150 – 12+350 191m Existing field ditch through WTA 6





13+000 – 13+100 216m Existing field ditches perpendicular to mainline footprint





14+120 – 14+160 80m Existing field ditch perpendicular to mainline footprint

14+280 – 14+360 64m Existing field ditches perpendicular to mainline and Garn Llyn Slip lanes

14+400 – 14+550 296m Existing field ditches perpendicular to mainline and Garn Llyn Slip lanes

16+390 53m Steelworks dedicated reen perpendicular to mainline footprint

16+400 – 16+460 74m Existing field ditch skewed to mainline footprint

16+850 – 17+100 814m Existing field ditches skewed to mainline footprint




17+520 – 17+880 799m Existing field ditches under mainline and WTA 9

17+900 134m Existing field ditches perpendicular to mainline footprint







File Note

March 2016

Page 5 of 9


Reason infilled



19+700 – 19+850 179m Existing field ditch parallel to mainline

Total 9136m

Infilling would have a negative impact the water management and biodiversity of the levels. Therefore

mitigation of this impact is proposed and outlined below.

4. Mitigation Proposals for Reens and Field Ditches

In order to mitigate for the loss in length of reen and field ditch, it is proposed that new reens are provided in

areas in which existing reens are being infilled. Continuing advice would be sought from NRW on their

specification for reen design, however in general the proposals are that the reens will be excavated to a

depth of 2.0m with 1 in 1 side slopes, a 0.7m berm and will be approximately 5.7m wide at the surface.

These engineered reens will connect reens that have been cut off by the highway, with tilting sluices to allow

manipulation of the water levels in the reen. A 7m width Section 250 easement for maintenance will be

provided. The reen will be placed 3m outside of the highway fenceline. Responsibility for maintenance is to

be agreed with NRW.

Where existing field ditches have been cut off by the works, replacement field ditches will be provided.

Continuing advice would be sought from NRW on their specification for field ditches however in general the

proposals are that these will be 2.5m wide at the surface with 1 in 1 slopes and 1m deep. These will connect

to the nearest main reens to provide connectivity and compensate losses.

Culvert crossings will be provided for each main reen, in order to maintain connectivity within the reen

system. For culverts which have no discernible catchment from FEH analysis, these are currently proposed

to be 1800 x 1800 concrete box culverts. The invert of these will be installed 150mm below the existing reen

bed level to allow a natural bed to form, and then will be partially submerged to allow the water level to be

maintained at SPL and WPL. There will be penstock sluices installed at each end, with the facility to

completely close the sluice between the culvert and reen in order to allow access for maintenance. There will

also be tilting sluices installed along the length of new reens where considered necessary to maintain the

extended reen network. Culverts with a catchment are currently proposed to be 1800mm height, with the

widths to be determined from the hydrological analysis. Culvert heights may be amended to allow mammals

(including bats) and other wildlife to cross.

Drawings M4CaN-DJV-HDG-ZG-GEB-DR-CD-0001 to 0016 in Appendix A show the current proposals for

the reen mitigation across the Scheme. Table 3 (below) shows the approximate length of replacement reens

provided.

Chainage North or south of

carriageway

Length provided

Reason of provision

5+100 – 5+520

North 426m Connect Nant-y-Moor reen to SDR reen to improve water management

5+100 – 5+300

South 194m Diversion of Nant-y-Moor reen

5+520 – 5+760

South 246m Diversion of Percoed reen and connection of SDR reen to Percoed reen

File Note

March 2016

Page 6 of 9


carriageway

Length provided

Reason of provision

6+000 – 6+700

North 775m Connection of Percoed reen to Morfa Gronw reen to improve water management

6+820 – 6+900

North 91m Diversion of Morfa Gronw reen

7+750 – 7-980 North 259m Connect Old Dairy Reen to Pont-y-Cwcw

8+050 – 8+400

North 365m Connect Pont-y-Cwcw reen to Sea Wall reen.

8+400 North 58m Divert Sea Wall Reen

19+120 – 19+300

North 145m Water flows diverted to Cock Street Reen

19+120 South 98m Existing ditch widened to outfall to Rush Wall Reen

Total 2657m

Table 4 (below) shows the length of proposed replacement field ditches across the scheme.


carriageway

Length provided

Reason of provision

4+320 – 4+520 North 209m Intercept ditches and transfer flow to culverts

4+420 – 5+100 South 658m Interception and diversion of flows to connect to Nant-y-Moor Reen, including flowing through Church Lane overbridge

5+510 – 5+760 North 219m Intercept ditches and transfer flows to Percoed Reen

5+760 – 6+130 South 472m Field ditch diversion around Water Treatment Area 4b

6+120 – 6+330 South 201m Ditch to intercept flows from drain

6+530 – 6+680 South 122m Intercept highway embankment runoff and direct to existing drains

6+680 –6+880 South 209m Intercept highway embankment runoff and direct to existing drains


7+400 – 7+750 North 302m Intercept flows from existing ditches and redirect towards culverts

7+400 7+500 South 90m Intercept highway embankment runoff and direct to existing drains



11+550 – 11+820

North 254m Intercept flows from existing ditches and redirect towards culverts

11+640 – 11+960

South 323m Intercept highway embankment runoff and direct to existing drains

11+810 – 12+350

North 591m Intercept flows from existing ditches and redirect towards Lakes Reen around Water Treatment Area 6

File Note

March 2016

Page 7 of 9


carriageway

Length provided

Reason of provision

11+960 – 12+090


12+350 – 12+470

North 97m Intercept flows from existing ditches and redirect towards Lakes Reen

12+670 – 12+910

North 327m Intercept flows from existing ditches and redirect towards Lakes Reen

12+850 – 13+000


13+000 – 13+310

North 12m Connect existing ditch to Julians Reen

13+000 – 13+050

South 43m Connect existing ditch to Julians Reen

13+000 – 13+900


13+900 – 13+960

South 161m Widen existing ditch to allow flows under new section of motorway

16+600 – 17+230


17+880 – 17+900


17+880 – 19+130


18+010 – 18+480


18+980 – 19+130


19+300 19+800 South 620m Intercept highway embankment runoff and direct to existing drains

19+830 – 19+950


Total 9771m

Table 5 (below) summarises the reen and field ditch lengths lost and new lengths provided.

Type Length infilled (m) New length provided (m)

Reens 2568 2657

Field ditches 9136 9771

The embankment of the proposed new section of motorway will also potentially truncate overland flow paths

during low probability flood events. The proposed engineered reens will seek to capture overland flow paths

and route flows to culverts below the proposed road embankment. The effectiveness of the proposals has

been tested as part of the Flood Consequences Assessment (Reference number M4CaN-DJV-HDG-

ZG_GEN-RP-CD-0007) for the scheme.

File Note

March 2016

Page 8 of 9

In order to encourage establishment of vegetation characteristic of the existing reen and ditch network,

material would be introduced into the new features from both existing reens and ditches being removed

(subject to timing) and also using material removed from the reen network arising from NRW’s annual

maintenance, again subject to NRW’s agreement.

As well as introducing appropriate plant species, this would also assist in establishing populations of aquatic

invertebrates.

Mammals, reptiles and amphibians would colonise the new watercourses as the vegetation develops.

All of the replacement reens have the potential to impact on archaeological remains within the Levels. Although it is intended to be able to identify areas of higher archaeological potential in KS3, it would be prudent to include the excavation of the replacement reens as an early activity in KS6. If archaeological sites are picked up during this work, they may well extend beneath the carriageway embankment, so the excavation of the replacement reens could be used as an additional form of archaeological evaluation which could alert us to areas where further archaeological investigation may be required. NRW have advised that any replacement lengths of reens and ditches are excavated, connected and functioning prior to the infilling of the sections to be lost in order to minimise disruption. 5. Conclusion

This note outlines the mitigation for the reens and field ditches for the Scheme. Reen connectivity will be

retained with the implementation of culverts, and a significant amount of additional reen length will be added

to the levels which will have a significant positive impact both on the biodiversity and the water management

along the levels.

Field ditches will also be reinstated along the edge of the Scheme, maintaining the current length of field

ditches infilled by the Scheme.

Side roads design will ensure that maintenance routes currently used by NRW to maintain reens will still be

available.

File Note

March 2016

Page 9 of 9

Appendix A

M4 CORRIDOR AROUND NEWPORT

HIGHWAY DRAINAGE AND REEN MITIGATIONSHEET 1 OF 16

Issue

D1FOR COSTING

1:2500 DJW

27/01/16

TJD

27/01/16

HR

27/01/16

BCS

27/01/16

Issue DJW TJD HR27/01/16 FINAL ISSUE TO WGM4CaN - DJV - HDG -

ZG_GEN - DR - CD - 0001

SAFETY, HEALTH AND ENVIRONMENTALINFORMATION

In addition to the hazards/risks normally associated with the types of workdetailed on this drawing, note the following significant residual risks(Reference shall also be made to the design hazard log).ConstructionNo exceptional risks

Maintenance / CleaningNo exceptional risks

UseNo exceptional risks

Decommissioning / DemolitionNo exceptional risks

Date

Scale

Drawing Title

Project TitleDrawing Status

DO

NO

T SC

ALE

Date Date DateClient Original Size

Suitability

Milli

met

res

100

100

A1Drawing Number Revision

Location Type Role Number

Project Originator Volume

Designed / Drawn Checked Approved Authorised

Rev. Date Description By Chk'd App'd

Project Team

Survey 100021874. Welsh Government.

Trwydded yr Arolwg Ordnans 100021874.

KEY PLANGENERAL NOTES:

1. ALL DIMENSIONS ARE IN METRES UNLESS NOTED OTHERWISE.2. ONLY WRITTEN DIMENSIONS SHALL BE USED, DO NOT SCALE.3. FIN DRAINS NOT SHOWN FOR CLARITY. TO BE HCD F18 TYPE 7.

LEGEND:

CATCHPIT - HCD F11 / MANHOLE - HCD F4, F5, F6 & F7

INTAKE CHAMBER - HCD F22 & F24

PETROL INTERCEPTOR

CONCRETE HEADWALL

GRASS LINED DITCH IN BOX CULVERT

CARRIER PIPE - HCD F1

CONCRETE CHANNEL - HCD F21 & B3 & B7 & B12

CONCRETE CHANNEL - HCD F21 & B3 & B7 & B12WITH CARRIER PIPE - HCD F1 BELOW

GRASS LINED CHANNEL

COMBINED KERB DRAINAGE

EXISTING NRW SLUICE

PROPOSED NRW TILTING WEIR / PENSTOCK

POTENTIAL NRW ACCESS (IN ABEYANCE)

INDIRECT LOSS FIELD DITCHES

SITE OF SPECIAL SCIENTIFICINTEREST BOUNDARY

REPLACEMENT REEN

REPLACEMENT FIELD DITCH

HIGHWAY CUT OFF DITCH

EXISTING REEN

EXISTING REEN TO BE FILLED

EXISTING FIELD DITCH TO BE FILLED

EXISTING CULVERT TO BE RETAINED

PROPOSED CULVERT

COMBINED KERB DRAINAGE WITHCARRIER PIPE - HCD F1 BELOW



Issue

D1FOR COSTING

1:2500 DJW

27/01/16

TJD

27/01/16

HR

27/01/16

BCS

27/01/16


ZG_GEN - DR - CD - 0002






Date

Scale

Drawing Title


DO

NO

T SC

ALE


Suitability

Milli

met

res

100

100






Project Team





LEGEND:



PETROL INTERCEPTOR

CONCRETE HEADWALL





GRASS LINED CHANNEL


EXISTING NRW SLUICE





REPLACEMENT REEN



EXISTING REEN




PROPOSED CULVERT




Issue

D1FOR COSTING

1:2500 DJW

26/01/16

TJD

26/01/16

HR

26/01/16

BCS

27/01/16


ZG_GEN - DR - CD - 0003






Date

Scale

Drawing Title


DO

NO

T SC

ALE


Suitability

Milli

met

res

100

100






Project Team





LEGEND:



PETROL INTERCEPTOR

CONCRETE HEADWALL





GRASS LINED CHANNEL


EXISTING NRW SLUICE





REPLACEMENT REEN



EXISTING REEN




PROPOSED CULVERT



SHEET 4 OF 16

M4CaN - DJV - HDG -

ZG_GEN - DR - CD - 0004

AC DOL HR BCS

AC DOL HR

1:2500

KEY PLAN:

HIGHWAY DRAINAGE AND REEN MITIGATION

INFORMATION

SAFETY, HEALTH AND ENVIRONMENTAL

(Reference shall also be made to the design hazard log).

detailed on this drawing, note the following significant residual risks

In addition to the hazards/risks normally associated with the types of work

Construction

Maintenance / Cleaning

Use

Decommissioning / Demolition

FIN DRAINS NOT SHOWN FOR CLARITY. TO BE HCD F18 TYPE 73.

ONLY WRITTEN DIMENSIONS SHALL BE USED, DO NOT SCALE.2.

ALL DIMENSIONS ARE IN METRES UNLESS NOTED OTHERWISE.1.

GENERAL NOTES:

D1

IssueP03

27/01/126/01/16 26/01/16

27/01/16 FINAL ISSUE TO WG

26/01/16

No exceptional risks

Culverts partially submerged



FOR COSTING

Date

Scale

Drawing Title


DO N

OT S

CA

LE


Suitability

Millim

etres

100

10

0

A1

Drawing Number Revision





Project Team


© Hawlfraint a hawliau cronfa ddata'r Goron 2015. Rhif


© Crown Copyright and database right 2015. Ordnance

Ppg Sta

Drain

Track

ETL

Ppg Sta

ETL

El Sub Sta

El Sub Sta

Wentlooge Level

Pont-estyll

11.0m

Maerdy Farm

Tk

Drain

El Sub Sta

CS

Drain

Spring

Drain

Drain

Pond

Drain

Path (u

m)

GREEN LANE

Drain

LANE (

Trac

k)

Drain

5.8m

Perc

oed

Reen

Drain

6.1m

Pond

Drain

PERC

OED

Drain

MP 162.75

Drain

Drain

Pat

h (u

m)

Drain

Drain

Drain

Drain

Drain

Drain

Signal Gantry

Drain

12.8m

Tra

ck

Tra

ck

Ponds

Trac

k

FB

FB

Drain

Drain

6.4m

Drain

Drain

Drain

Drain

Drain

FB

Drain

Drain

Drain

Drain

Drain

Drain

Sluice

6.7m

ETL

Drain

Drain

Farm

Morfa-Gronw Reen

Ty-hir

Pond

Fair Orchard

Drain

FB

Drain

Drain

Drain

Drain

Dulce Domum

LIG

HT

HO

US

E

RO

AD

Ne

w

Dairy

Reen

Drain

Pear Tree Cottage

Pond

Drain

4

11

1

15

GR

OS

MO

NT

WA

Y

CONWAY GROVE

1

5

4

9

8

7

62

14

848

BR

ON

LLYS

GR

OVE

64

1

18

2

6

Llanidloes

Mews

39

10

11 to 17

1

11

2

21

11

15

29

1

Drain

18

DUNR

AVEN D

RIVE

16

27

2

BUIL

TH

CL

OS

E

PO

WIS

CL

OS

E

37

5

OX

WIC

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GR

OVE

3

1

9

33

1

12

11

15

21

17

19

6

6

10

BR

ON

LL

YS

ME

WS

33

Drain

Drain

LIG

HTH

OUSE

RO

AD

MP 160.5

ED

Bdy

CR

7.0m

PE

NC

AR

N

LA

NE

Old

Dairy

Reen

Drain

Drain

Drain

FB

13.3

m

MP 161.2

5

6.7

m

FB

Drain

Drain

Trac

k

Drain

Drain

Pond

Drain

Farm

B 4239

7.3m

Whitecross

Drain

ETL

Drain

FB

Morfa-

Gron

w

Reen

Cottage

Drain

Drain

Drain

Drain

Railway

Drain

Drain

Drain

Drain

Drain

Drain

Cotta

ge

MP 161.5

15

11

12

14

16

6.1m

ETL

Drain

Drain

Drain

Sluice

WHEE

L LAN

E

Drain

Drain

S Gantry

Morfa-

Gron

w

Reen

Drain

Drain

Drain

ETL

Drain

5.8m

Wentlooge Level

Drain

Path (u

m)

(Track)

MP 162

FB

MP 161.75

Drain

Ty-hîr

89

Tank

11

30

25

50

RO

SA

MU

ND

CL

OS

E

Sluice

ETL

36

7.0m

58

Drain

4

PENCARN LANE

Drain

45

Old Dairy Reen

91

S

Gantry

Drain

ETL

Drain

Drain

35

6.7m

6

Drain

Drain

Drain

Drain

76

JANE CLO

SE

Tredegar Park

9

4O

Drain

Drain

Drain

CS

ED Bdy

14

22

29

Ffynnon-

wen

Reen

1

32

8

30

MO

RG

RAIG

AVE

NU

E

PIC

TO

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WAL

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1

34

37

5

NAR

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CLOSE

2

El Sub Sta

KID

WELLY

CLOSE

25

2

2

27

10

12

14

35

9

6

5

3

4710

8

20

18

OYSTERMOUTH WAY

36

48

3

54

Sluice

37

3 to 8

ETL

Drain

Wentlooge Level

Drain

10

12

1

3011

5

1

TENBY CLOSE

34

OLD

7

CASTLE

CLOSE

25

24

15

26

1

39

23

17

43

15

11

41

1

Perco

ed Ree

n

25

ETL

8

1

22

14

Sluice

2

Drain

St Briavels Mews

PE

RC

OE

D

LA

NE

20

Drain

12

Drain

12

Morfa

-Gro

nw

Reen

2

31

15

LO

NG

TO

WN

GR

OVE

18

2

51

10

6

26

CRICCIETH CLOSE

9

17

12

34

1

1

9

1

Def

Drain

Drain

71

MEWS

MEWS

OYSTER

MO

UTH

SKENFRITH

81

Mast (Telecommunication)

FB

5800

5900

6000

6100 6200

6300

6400

6500

6600

6700

6800

6900

7000

7100

7200

7300

7400

7500

7600

7700

HIGH POINT

OUTFALL 4 OUTFALL 5

PERCOED REEN

MORFA-GRONW REEN

REEN

MORFA GRONW

OUTFALL TO

REEN ACCESS

SMN-0630 COMPENSATORY

CULVERT

SMN-0685 TY-HIR

CULVERT

GRONW REEN

SMN-0680 MORFA COTTAGE CULVERT

SMN-0730 RAILWAY

M4Ca

N-D

JV-H

DG-Z

G_

GE

N-D

R-C

D-0

005

FO

R C

ON

TIN

UA

TIO

N S

EE D

RA

WIN

G

M4

Ca

N-D

JV-H

DG-Z

G_

GE

N-D

R-C

D-0

003

FO

R C

ON

TIN

UA

TIO

N S

EE D

RA

WIN

G

W69x

W69a x

W73

WTA5

CHANNEL

TRANSITION TO GRASSED

REED BED 5

LEGEND:

INTEREST BOUNDARY

SITE OF SPECIAL SCIENTIFIC



PROPOSED NRW TILTING WEIR/PENSTOCK

EXISTING NRW SLUICE


GRASSED CHANNEL

WITH CARRIER PIPE - HCD F1 BELOW




GRASSED CHANNEL IN BOX CULVERT

CONCRETE HEADWALL

PETROL INTERCEPTOR



CARRIER PIPE - HCD F1 BELOW

COMBINED KERB DRAINAGE WITH

PROPOSED CULVERT




EXISTING REEN



REPLACEMENT REEN

Issue


SHEET 5 OF 16

M4CaN - DJV - HDG -

ZG_GEN - DR - CD - 0005

AC DOL HR BCS

AC DOL HR

KEY PLAN:

1:2500


INFORMATION





Construction


Use


FIN DRAINS NOT SHOWN FOR CLARITY. TO BE HCD F18 TYPE 7.3.



GENERAL NOTES:

IssueeP03

27/01/1626/01/16

27/01/16


Main bridge drainage to outfalls at bridge abutment

Culverts partially submerged



D1

26/01/16

FINAL ISSUE TO WG

26/01/16

FOR COSTING

Date

Scale

Drawing Title


DO N

OT S

CA

LE


Suitability

Millim

etres

100

10

0

A1






Project Team





Mud

FB

FB

Cattle grid

Drain

Farm

Reen

Old Dairy

New

Drain

Dairy

ETL

FB

FB

FB

Drain

Drain

Drain

Wentlo

oge Le

vel

FB

FB

Refuse Tip

Mud

Ebb

w

River (Afo

n

Eb

wy)

Water

Track

Mud

Mud

Mud

Track

Mud

Def

ED Bdy

Mean

Hig

h

Water

Colle

cts

Mean

Hig

h

Water

Mean

Lo

w

Water

Mean

Hig

h

Water

Colle

cts

Colle

cts

L Col

Track

Mud

Water

ED Bdy

Def

Mud

Mud (A

fon

Eb

wy)

Ebb

w

River Mu

d

Mud

CC

LW

Mud

Drain

Track

ED

Bdy

L Twr

L Twr

L Twr

TO

M

LE

WIS

WA

Y

Water

Water T

rack

Def

ED

Bdy

MLW

Mud

Drain

Drain

Drain

Drain

7.3

m

Drain

Water

Drain

ETL

Mud

13.2

m

Drain

Mud

Tredegar

Pill

Drain

Issues

Mean

Hig

h

Water

Mean

Hig

h

Water

(Afo

n

Eb

wy)

Drain

Ebb

w

River

MudDrain

LIGH

THOU

SE R

OAD

ETL

Drain

MP 160.5

Track

Def

ED Bdy

ED B

dy

CS

CR

ED

Bdy

CC

LW

Def

Drain

Drain

7.0

m

Drain

PEN

CAR

N LANE

Drain

Old

Dairy

Reen

7.0

m

Drain

Drain

Drain

Drain

PO

NT-

Y-

6.9

m

HE

OL

Drain

Pont-

y-

cw c

w

Reen

Drain

Sluice

Drain

CW

CW

FB

13.3

m

MP 161.

25

Track

Drain

Wentlo

oge Le

vel

6.7

m

6.7

m

FB

6.9

m

ETL

Drain

Drain

Drain

Drain

Track

Drain

Pond

Farm

White

cross

Sluice

FB

Tank

30

36

45

S Gantry

35

4O

Mast

(Telecom

municatio

n)

Landing Sta

ge

Bollards

Bol

L Twr

Bol

L Twr

Bol

Bollards

L Twr

L Twr

Sloping

maso

nry

L Twr

Bol

Bol

El

Sub Sta

Weighbrid

ges

Travelling Crane

Conve

yor

Bollards

WBs

Bol

L Twr

Bollards 8.8m

Bol

Bol

8.8

m

Tim

ber

Storage

Shed

L Twr

Bol

Weighbrid

ge

Tank

Bol

Bollard

Bolla

rds

L Twr

Bollard

Bolla

rds

Bollard

Bol

SM

Tank

Tank

Tower

SM

SM

SM

SM

MoP

El

Sub Sta

Travelling Crane

North Quay

Conve

yors

Tank

Jetty

Bolla

rds

Bollard

Jetty

Bol

Bollard

Bol

Bollard

Storage Shed

10.4

m

Bollard

L Twr

Bollard

10.4

m

Slo

pin

g

masonry

Bol

WBs

Weighbrid

ge

10.4

m

Lightin

g To

wer

Timber

Yard

L Col

L Col

El

Sub Sta

L Col

L Col

L Col

El

Sub Sta

Level

Crossin

g

Level

Crossin

g

Tanks

SM

SM

Railw

ay

Crossin

g

Jetty(d

isuse

d)

ESS

Tank

WB

7600 7

700 7

800 7900

8000

8100 82

00

8300

8400

8500

8600

8700

8800

8900

9000

9100

9200

9300 9400

9500

REEN CULVERT

SMN-0775 OLD DAIRY

REEN CULVERT

SMN-0800 PONT Y CWCW

REEN BRIDGE

SBR-0835 SEA WALL

CULVERT

COMPENSATORY REEN

SMN-0805 PONT Y CWCW

FARM CULVERT

SMN-0810 NEW DAIRY

CULVERT

REEN FIELD ACCESS

SMN-0770 OLD DAIRY

OLD DAIRY REEN

PONT Y CWCW REEN

SEA WALL REEN

FO

R C

ON

TIN

UA

TIO

N S

EE D

RA

WIN

G

M4

Ca

N-D

JV-H

DG-Z

G_

GE

N-D

R-C

D-0

004

FO

R C

ON

TIN

UA

TIO

N S

EE D

RA

WIN

G

M4

Ca

N-D

JV-H

DG-Z

G_

GE

N-D

R-C

D-0

006

FOR CONTINUATION SEE DRAWING

M4CaN-DJV-HDG-ZG-GEN-DR-CD-0016

W81

W77a

W77

W94

CROSSING DRAINAGE

OUTFALL FROM USK

TO RIVER EBBW

WEST OUTFALL

TO RIVER EBBW

EAST OUTFALL

LEGEND:

INTEREST BOUNDARY

SITE OF SPECIAL SCIENTIFIC



PROPOSED NRW TILTING WEIR/PENSTOCK

EXISTING NRW SLUICE


GRASSED CHANNEL

WITH CARRIER PIPE - HCD F1 BELOW




GRASSED CHANNEL IN BOX CULVERT

CONCRETE HEADWALL

PETROL INTERCEPTOR



CARRIER PIPE - HCD F1 BELOW

COMBINED KERB DRAINAGE WITH

PROPOSED CULVERT




EXISTING REEN



REPLACEMENT REEN

Issue


SHEET 6 OF 16

M4CaN - DJV - HDG -

ZG_GEN - DR - CD - 0006

AC DOL HR BCS

AC DOL HR

1:2500

KEY PLAN:


INFORMATION





Construction


Use


FIN DRAIN NOT SHOWN FOR CLARITY. TO BE HCD F18 TYPE 7.3.



GENERAL NOTES:

IssueP03

26/01/16 27/01/16

27/01/16

Large diameter pipe underneath bridge deck

Large diameter pipe underneath bridge deck



D1

26/01/16

FINAL ISSUE TO WG

26/01/16

FOR COSTING

Date

Scale

Drawing Title


DO N

OT S

CA

LE


Suitability

Millim

etres

100

10

0

A1






Project Team





ETL

ETL

DW

Bollards

Bollard

Bollard

6.7m

MP 1.75

Tanks

MP 2

New House

Tanks

Tank

TRASTON ROAD

Drain

CO

RP

OR

ATIO

N

Drain

MP 1.75

8.5m

EAST

BA

NK

RO

AD

7.3m

7.0m

Hopper

Drain

Works

Drain

6.7m

ETL

RO

AD

Hopper

Depot

8.5m

Depot

Drain

Tank

18

Drain

Works

8.5m

Mud

8.5m

El

El Sub Sta

Depot

7

10

6

Tra

ck

Mud

8.5m

Path

Sand

NEW QUAY ROAD

ETL

8.5m

Bollards

Pond

Works

1

Works

Mud

BR

OAD

QU

AY

RO

AD

11

Cold

Harb

our

Reach

ETL

8.5m

Sub Sta

Mud

Mud

Mud

Jetty

EAST

BAN

K R

OAD

9.4m

Mud

Mud

Mud

Sloping

maso

nry

9.4m

8.5m

8.8m

Dolphin

Mud

9.1m

Jetties

Dolphin

Custom

Mud

9.4m

Transit

Shed (N

o 3)

East Lo

ck

8.5m

Mud

DW

Bollard

Bollard

DW

Bollards

Bollards

Mud

DW

Bollards

DW

Bollard

House

Bollards

L Twr

Bollard

Mud

Bollard

Sand

El Sub Sta

El Sub Sta

Mud

Outfall

8.5m

Mud

8.8m

NTL

Depot

Mud

Bol

Bol

Drain

Mud

Mud

Mud

Mud

Drain

Shin

gle

Mud

8.5m

Bollards

7.6m

7.9m

Pier

8.5m

Bollards

8.8m

Pier

Pond

Tra

velling Cra

ne

8.8m

Bol

Sand

MLW

El Sub Sta

Forest House

Weighbridge

CR

CCL

W

Co Const,

Asly

Const

& ED Bdy

CCLW

Co Const, Asly Const & ED Bdy

CCLW

Co Const,

Asly Const

& ED Bdy

Tanks

Tank

Tanks

Mud

MH

W

Mean

High

Water

River

Usk (Afo

n

Wys

g)

Mean

High

Water

Mean High W

ater

Cold Harbour Reach

Drain

Drain

MoP

MoP

MoP

MoP

Mean

High

Water

MH

W

Caldicot Level

Caldicot Level

Caldicot Level

DW

Travellin

g Cra

nes

East

Quay

Lighting Tower

Tanks

Mud

Stevenson Street

Industrial Estate

Easter

n

Dock

Drain

Tank

Mast

Tanks

Tank

Drain

Tanks

Tank

WB

Mud

Tanks

WB

Tanks

Tanks

Mud

TankDrain

Tanks

WB

Drain

Lighting Tower

Tank

MH

W

ESS

El Sub Sta

Electricity

Distribution Site

ESS

ESS

El Sub Sta

El Sub Sta

Mean High

Water

Mean

Lo

w

Water

Works

Cold

Harbour

Reach

Sluice

Drain

SM

Mud

Drain

Mud

Mud

Shin

gle

ETL

Sluice

Tank

Drain

Mean

Hig

h

Water

Mean

Hig

h

Water

Mean

Lo

w

Water

MoPs

MoPs

MoPs

WB

8.8m

TCB

Sub Sta

8.8m

El

(No

5)

Capsta

n

Transit

Shed

8.8m

Trav

ellin

g Cr

ane

Sout

h Qua

y

Capsta

n

8.8m

Shingle

Cold

Harb

our

Reach

Mud

CC

LW

Co

Const,

Asly

Const

& E

D

Bdy

Bol

Bollard

L Twr

South Dock

Tank

L Twr

L Twr

L Twr

Newport Docks

Landing Stage

Bollards

L Twr

Bol

L Twr

Bol

Bollards

L Twr

Sloping masonry

L Twr

Bol

Bol

El Sub Sta

Weighbridges

Trav

ellin

g Cr

ane

Conveyor

WBs

Tim

ber

Stora

ge Shed

L Twr

Tank

Tank

Tower

Trav

ellin

g Cr

ane

North Q

uay

Conveyors

Tank

Bollards

Jetty

Bollards

Bollard

Bollards

Bol

Bollards

Bollard

Dolphins

Jetty

Bollard

Bols

Bol

Bollard

Dolphin

Bollard

Graving

Dock

9.1m

Bollard

s

9.1m

8.8m

Jetty

9.4m

L Twr

9.1m

(disused)

Bollards

Bollard

Mud

WB

(disused)

Chy

9.1m

9.1m

Bollards

ETL

8.8m

Bollard

Pier

Bollards

Tra

ck

Jetty

Mud

L Twr

El Sub Sta

Tra

nsit

Shed

Mud

(disused)

9.1m

Cold

Harb

our

Reach

(disused)

Dolphins

9.1m

Bollard

Bollard

Bollard

s

Jetty

9.4m

Jetty

Dolphins

Tim

ber

Yard

(disused)

Bollards

Bols

Bol

Coal Hoist No 13

Bollards

Bollards

Bol

Bollards

Bollard

9.0m

Sloping masonry

8.8m

Storag

e Sh

ed

Caisson

10.4m

L Twr

Bollards

Bollard

L Twr

Central

Wor

ksho

ps

9.4m

Bollard

Bol

10.4m

Cn

Sloping

maso

nry

9.4m

Bol

Bollard

L

Twr

9.1m

Bollards

Bol

Bol

Bollard

Bollards

WBs

Weighbridge

Bollard

Bollards

10.4m

SM

Lighting Tower

L Col

El Sub Sta

L Col

L Col

Timber Yard

L Col

L Col

L Col

El Sub Sta

L Col

L C

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