mattishall forge, kensington strategy development drainage

Proposed Housing Development – Kensington Forge, M

attishall

Drainage Strategy

PROPOSED HOUSING DEVELOPMENT

KENSINGTON FORGE, MATTISHALL

Drainage Strategy

Client: Mr & Mrs Plummer

Engineer: Create Consulting Engineers Limited

15 Princes Street

Norwich

Norfolk

NR3 1AF

Tel: 0845 450 7908

Email: [email protected]

Web: www.createconsultingengineers.co.uk

Report By: Philip Porter, IEng, MCIHT, AMICE

Checked By: Gordon Hodgkinson

Reference: PP/CS/P12‐381/01

Date: April 2014

Proposed Housing Development – Kensington Forge, M

attishall

Drainage Strategy

Proposed Housing Development – Kensington Forge, Mattishall Drainage Strategy

Ref: PP/CS/P12‐381/01 Page 1

PROPOSED HOUSING DEVELOPMENT

KENSINGTON FORGE, MATTISHALL

Drainage Strategy

Contents

1.0 Introduction

2.0 The Site History

3.0 The Site Proposals

4.0 Existing Surface Water Drainage

5.0 Proposed Surface Water Drainage Strategy

6.0 Proposed Foul Water Drainage Strategy

7.0 Guidance and Policies

8.0 Discussion and Recommendation

9.0 Disclaimer

Appendices

A. Proposed Masterplan for Site

B. Drainage Strategy Drawing

C. Windes (Microdrainage) Calculations

D. Anglian Water Asset Plan

Registration of Amendments

Revision Amendment Details Revision

Prepared By

Revision

Approved

By



1.0 INTRODUCTION

1.1 Mr and Mrs Plummer of Kensington Forge, Dereham Road, Mattishall, have applied to

Breckland District Council for a change of use on an area of land that they own from mixed

residential and light industrial to residential. This report describes the strategy for draining

the land.

1.2 The Strategy Statement demonstrates that:

a. It is possible to drain the site to outfall in the ditch along the sides of the property.

b. Connections to the foul water sewer are available.

1.3 The surface water management proposals demonstrate that there is no increased risk of

flooding within the site or onto adjacent areas of land.

1.4 This Statement is prepared in support of and as an explanation to the calculations and

drawings included as appendices to this report.

1.5 The development is contained within Zone 1 which is defined by the Environment Agency as

‘land having less than 1 in 1,000 annual probability of river or sea flooding’. The

Environment Agency identifies that all uses of land are appropriate in this zone. It is also

identified that flood risk assessments or drainage strategies are only appropriate within

Zone 1 for sites of 1 Hectare or above. The site reviewed herein is 0.947 Hectares in area

but a drainage strategy has been called for by the local planning authority.



2.0 THE SITE HISTORY

2.1 The Site is located to the south of Dereham Road on the western side of the village of

Mattishall, as shown below in Figure 2.1.

Contains Ordnance Survey data © Crown copyright and database rights 2013.

Figure 2.1: Site Location

2.2 The site has had a number of uses over the years, commencing as agricultural land with

various parts of the site being designated for residential, light industrial and wood recycling

over the years.

2.3 Currently, the front part of the site adjacent to Dereham Road contains a workshop building

used as a welding shop and office and an incomplete storage building. Towards the rear of

the site and on the eastern boundary, a mobile home and garden are sited and the south

west of the site is currently an area of grassland and outside storage that enjoys planning

approval for use as a wood recycling facility.

Site Location



3.0 THE SITE PROPOSALS

3.1 As stated previously, the site currently has the benefit of a mixture of residential and light

industrial planning approval.

3.2 The proposal, subject to planning approval, is to clear the site of the existing uses and erect

eleven dwellings constructed to Passivhaus standards. Of these eleven dwellings, four

would be offered as affordable housing.

3.3 The site would be accessed via a new junction with the Dereham Road located along the

northern boundary of the site. This access road would be constructed to adoptable highway

standards (ie have an impermeable paved area) with the driveways servicing the properties

along its length, being constructed of permeable paving materials.

3.4 Drawing 3098.06.D enclosed in Appendix A shows the proposed layout of the site.



4.0 EXISTING SURFACE WATER DRAINAGE

4.1 The site is currently drained by a combination of very small soakaways and overland flow to

outfall in the existing ditch.

4.2 The existing forge and mobile home are served by soakaways. The ground conditions on the

site consist mainly of Boulder Clay with some Alluvial Fan along the eastern boundary of the

site. Neither of these materials is particularly free draining and therefore the soakaways

used are relatively large in relation to the flow of water they cater for.

4.3 The workshop and mobile home are serviced by soakaways with the remainder of the site

draining to the ditch by means of overland flow. In the area of the workshop and

incomplete storage building, there is a small yard area paved with compacted stone and

gravel and a small area of grass land. To the rear of the site lies the residential area which is

mainly surrounded by grassland. Whilst the residential units are served by soakaways, the

remainder of the area relies upon overland flow to the ditches along the western boundary

of the property.

4.4 The open storage land to the south of the property is served wholly by overland flow. It

consists of an overgrown grassed area with a few spoil heaps from previous building works

spread around. The area is currently used for the external storage of wood and vehicles.

4.5 The run off from this area flows overland to the ditch along the western edge of the

property.

4.6 The ditch along the western edge of the property is approximately 1.2m deep throughout its

length. The top and lip of the ditch sides are well covered with vegetation and the bottom

has a layer of rotting leaves but is generally clear.

4.7 The ditch falls from the south west corner of the site along the western boundary towards

Dereham Road. As it approaches the road, it flows to the west to become a ditch parallel

with the south channel of Dereham Road. The depth of the ditch along this section is slightly

less than that along the boundary of the property. Despite a period of heavy rain prior to

the site inspection, there was no sign of the ditch overtopping the banks and flowing onto

either the road or the fields.



5.0 PROPOSED SURFACE WATER DRAINAGE STRATEGY

5.1 In formulating this drainage strategy, due recognition has been taken of the ground

conditions indicated by the BGS mapping. The ground strata of either the Alluvial Fan or the

Boulder Clay would indicate that soakage rates would be very poor. For this reason, a

prudent approach has been taken to assume that stormwater from roofs and the access

road can be put to a soakaway but should be taken to a positive outfall.

5.2 The approach taken in the design of the surface water drainage network for the site has

been to provide attenuation near to the point of collection before discharging into the piped

network that runs under the access road. Pipes in the network under the access road have

been appropriately sized to accommodate flows from the attenuation to the discharge point

at the ditch to the northeast corner of the Site.

5.3 In undertaking the preliminary drainage design, rainfall data has been identified from the

latest available EA data. Impermeable areas have been calculated from the latest architect’s

masterplan drawing number 3098.06.D and the run off input into Microdrainage to calculate

the flows in each run of the pipe network. Flow restrictions to determine the level of

attenuation have been built into the model.

5.4 To inform the drainage strategy, the DoH 124 Calculation of Greenfield Runoff Rate has been

used to establish a rate of runoff for the 1 in 100 year storm (+30% climate change) to the

ditch outfall. Based on a proposed impermeable area of development of 0.379 ha, the rate

for the 1 in 100 year storm (+30% climate change) is 4.2 l/s. Owing to the practicalities of

controlling waterflow rates, a rate of 5 l/s has been used.

5.5 This strategy proposes the use of a vortex control device (HydraBrake or Similar) to control

the flow of stormwater to no more than 5 l/s in the critical 1 in 100 year storm (+30%

climate change). Water is proposed to be attenuated within below ground cellular storage

creates (Wavin or similar).

5.6 Flows from the roofs of plots 1 to 5 will be stored in cellular storage structure located to the

rear of the plots with flows to the drainage network controlled by an orifice plate.

5.7 Stormwater from the impermeable access road and the roofs of plots 6‐11 will be directed

to the drainage network laid under the access road with the ultimate flow to ditch controlled

by a vortex control device. Attenuation, again in the form of below ground cellular storage

structure is proposed to the rear of plots 8‐11.

5.8 The indicative drainage network is shown on the attached drawing in Appendix B.

5.9 The detailed design of the drainage system will be undertaken in accordance with Sewers for

Adoption (6th Edition). Although it is not known at this time whether or not the sewer would



be offered for adoption, it has been decided to design and construct to these standards to

retain the option of offering it for adoption at a later date.

Alternative Strategies

5.10 The alternative strategies considered during the development of this preferred design are

discussed below:

Soakaways

5.11 As stated earlier, BGS data has been reviewed and it is noted that the sub‐soils indicated are

unlikely to offer any real infiltration. On this basis, the decision was taken to adopt the most

cautious approach possible direct roof and access road water to a positive outfall. In this

manner, should the developer wish to consider soakways at a later date, these could be

added into the system (subject to testing and suitable infiltration rates).

Grass Swales or Basins

5.12 As can be seen from the architect’s drawing, neither the site nor the masterplan layout

would be suitable for swales or basins.

Permeable Paving

5.13 Permeable paving has been considered and driveways to all plots are proposed to be gravel.

Storage beneath the access road pavement could be provided by granular fills. However,

permeable paving is not considered to be an adoptable form of road construction by the

local highway authority. This option has therefore been discounted on adoption grounds.

Detention Ponds and Swales

5.14 The site area is restricted and there is little space available for such features and the health

and safety implications of deep water near to residential property would preclude this

option.

Below Ground Attenuation

5.15 The primary advantage of this alternative is the fact that the storage areas can be covered

by other uses, such as open space or gardens.

5.16 The proposed storage structures have been sited in garden areas and below a parking court.

The drawing shows the areas proposed for the construction of the storage features but the

size and number (ie smaller spaced out structures instead of a large central structure) will be

determined at the detailed design stage.



6.0 PROPOSED FOUL WATER DRAINAGE STRATEGY

6.1 As can be seen from the attached Anglian Water Asset Plan located in Appendix D, a foul

sewer serving the site and adjacent properties lies in Dereham Road immediately adjacent to

the site boundary.

6.2 Foul water runs towards Manhole 3402 outside the site from both directions along Dereham

Road. From this manhole, the foul water discharges across the road into a pumping station

adjacent to the farm track, ultimately discharging to a treatment works via a pumping main.

6.3 This strategy proposes a foul sewer network serving all the proposed properties laid within

the alignment of the proposed access road, discharging to Anglian Water foul sewer

described upstream or at Manhole 3402.



7.0 GUIDANCE AND POLICIES

7.1 Sewers for Adoption 6th Edition provides guidance to developers for the design and

construction of both Surface and Foul Water Sewers to be offered for Adoption. This

guidance is provided in consultation with the Water Undertakers.

7.2 The guidance in Sewers for Adoption states:

“An appropriate flow simulation method based on the Wallingford Procedure should be used

for hydraulic design unless otherwise greed with the undertaker, eg in the case of small

developments.”

Windes (Microdrainage) has been used for all the calculations herein.

7.3 The Building Regulations 2000, Part H ‘Drainage and Waste Disposal’, gives guidance on the

design of private sewers. Part H3 deals specifically with Rainwater Drainage.

7.4 The designs and calculations included herein conform to all of this guidance.



8.0 DISCUSSION AND RECOMMENDATIONS

8.1 The Environment Agency mapping has been consulted and has shown that the site lies

within Zone 1 and is defined as having a ‘very low’ risk of flooding from rivers or surface

water run off. Very low is defined by the Environment Agency as having a chance of flooding

of less than 1 in 1,000 years.

8.2 The Environment Agency guidance identifies that sites having a site area of less than

1 Hectare and included within Zone 1 on the flood maps do not require a Flood Risk

Assessment. However, it also advises that sites greater than 1 Hectare, whilst still not

requiring a full Flood Risk Assessment, should have a defined Drainage Strategy to identify

that the site can be adequately drained without creating a risk of increased flooding to

properties elsewhere. The site examined herein is approximately 0.947 Hectares in area.

However, in the interests of a robust design, the Strategy presented herein is provided in

support of the application.

8.3 A review of British Geological Society (BGS) mapping has indicated that the site is founded

upon impermeable sub‐soils that are likely to have very low soakage rates. The ground

conditions have been confirmed by inspection on site. In the interests of a prudent analysis,

therefore, the use of soakaways has been discounted and the drainage designed to outfall to

a local watercourse whilst keeping the outfall rates down to the equivalent ‘Greenfield’ run

off rates of 5 l/s.

8.4 The historical records for the area have been reviewed and it is noted that there are no

records of flooding to adjacent properties or highways within the area.

8.5 The SUDS Strategy therefore utilises a combination of retention features and flow controls

via a piped system to a positive outfall in a local watercourse. The provision of this system

enables the outflow to be constrained to the equivalent outfall of the existing undeveloped

site area. It therefore complies with the basic requirement of SUDS systems to reduce the

impact of the development on flood risk to surrounding properties.

8.6 The cellular structures intended to be used as attenuation features have been sited within

the rear gardens and amenity areas of the property. Whilst the initial design indicates the

use of a central feature serving a number of properties, further detailed design may indicate

that smaller more separated facilities would be better provided assuming that the capacity

of the single features is equalled or bettered.

8.7 Storage within the suitable sized pipe network may also be used to control outflows at the

detailed design stage.

8.8 Foul drainage would be directed to the existing manhole and pumping station immediately

adjacent to the existing site entrance.



8.9 In keeping with good hydraulic design practice, all drainage runs and structures will be

designed to ensure that self‐cleaning velocities are achieved in order to reduce the risk of

blockages.



9.0 DISCLAIMER

9.1 Create Consulting disclaims any responsibility to the Client and others in respect of any

matters outside the scope of this report.

9.2 The copyright of this report is vested in Create Consulting Engineers Ltd and Paul Plummer.

The Client, or his appointed representatives, may copy the report for purposes in connection

with the development described herein. It shall not be copied by any other party or used for

any other purposes without the written consent of Create Consulting Engineers Ltd or Paul

Plummer.

9.3 Create Consulting Engineers Ltd accepts no responsibility whatsoever to other parties to

whom this report, or any part thereof, is made known. Any such other parties rely upon the

report at their own risk.

APPENDICES

APPENDIX A

This line measures 200mm in length when printed correctly

Project:

Client:

Title:

Date:Revision Details:

Parsons + Whittley Ltd Architects

1 London Street, Swaffham

Norfolk, PE37 7DD

Phone: 01760 722000

email: [email protected]

web: www.parsonswhittley.co.uk

3098.06 D A

2draw

ing number: rev: size:

Proposed PASSIVHAUS DevelopmentKensington ForgeDereham RoadMattishall

Mr & Mrs P Plummer

Site Plan

07-04-14

1:500 Site Layout

n

1 2 3 45

6

7

11Typical dwellings 1-7 shown @ 2420sq ft/ 225 sqm, excluding garages and car-ports,

plots 8, 10 & 11 shown as 4-person 2-bed affordable homes @ 818 sq ft/ 76sqm

plot 9 shown as 2-person 1-bed affordable home @ 603 sq ft/ 56sqm

8 9 10

plots 7-11 and access road revised

Dereham Road

existing access to be stopped up and landscaped to NCC requirements

existing forge to be demolished

Dereham Road

1:2500 Site Location

n

tree to be removed

existing footpath to village

link development to existing footpath

existing Konect 4 bus stop at entrance to development

existing Leylandii hedge along western boundary to be removed

slab level xx.xx

slab level xx.xx

slab level xx.xx

slab level xx.xx

double garage 2

double garage 3

double garage 1

slab level xx.xx

triple garage 4 triple

garage 5slab level xx.xx

slab level xx.xx

slab level xx.xx

double garage 6

slab level xx.xx

slab level xx.xx

double garage 7

slab level xx.xx

Plots 8-11 slab level xx.xx

refer to arboricultural report for details of root protection areas to existing trees

native-species hedge and tree planting to boundaries to form part of a lanscaping scheme to be submitted to, and approved by, local authority

size 3 turning

access road to NCC Norfolk Residential Design Guide adoptable standard, type 6

private drives shown thus

existing Konect 4 bus stop at entrance to development

refer to engineer's drawing xxx for details of new access and visibility splay

slab level xx.xx

existing buildings to be removed shown dotted

PRELIMINARY

APPENDIX B

PLOT 1

FFL: 45.000

PLOT 2

FFL: 45.000

PLOT 3

FFL: 45.000

PLOT 4

FFL: 45.000

PLOT 5

FFL: 45.000

PLOT 6

FFL: 45.500

PLOT 7

FFL: 44.000

PLOT 8, 9, 10

FFL: 44.000

1.002

1

.

0

0

3

1

.0

0

4

1

.0

0

5

1

.0

0

6

1

.

0

0

7

1.001

ORI

GIN

AL

SHEE

T SI

ZE -

A1

Land

scap

eD

O N

OT

SCA

LE

DRAWING No REVISIONCLIENT

JOB No

SCALE(S)

DRAWING STATUSDATE

DESIGNED DRAWN

CHECKED APPROVED

PROJECT

DRAWING TITLE

AMENDMENT DETAILSREV DATE APPROVEDDRAWN

381

02/001 -MR. AND MRS. PLUMMER

KENSINGTON FORGE

PROPOSED DRAINAGE STRATEGY

22.04.14 INFORMATION

1:500GH TH

GH GH

Create Consulting Engineers accept no responsibility for any unauthorised amendments to this drawing. Only figured dimensions are to be worked to. COPYRIGHT © RESERVED

CELLULAR STORM WATER STORAGE

SIZED TO ACCOMMODATE THE 1 IN 100

YEAR (+30% CLIMATE CHANGE) STORM

EVENT WITH A CONTROLLED RATE OF

NO MORE THAN 5+ L/S THE EQUIVALENT

GREEN FIELD RATE INTO THE DITCH

HYDROBRAKE (OR SIMILAR)

FLOW CONTROLLED TO 5 L/S

CELLULAR STORM WATER STORAGE FLOW

CONTROLLED TO 5L/S BY ORIFICE PLATE

DEPTH OF DITCH CIRCA 1.2m

PROPOSED STORM WATER SEWER

PROPOSED FOUL WATER SEWER

PROPOSED STORM WATER MANHOLE

PROPOSED FOUL WATER MANHOLE

CELLULAR STORM WATER STORAGE

KEY:

NOTES:

1. THIS DRAWING IS BASED ON TOPOGRAPHIC SURVEY PROVIDED BY EAST ANGLIANSURVEYS LTD DRAWING NO. "8360-1" DATED 28.06.2013 AND MASTER PLANPROVIDED BY PARSONS + WHITTLEY LTD ARCHITECTS DRAWING "3098 current d - engissue" RECEIVED 01.04.2014.

FOUL SEWER TO

DISCHARGE TO

ADOPTED SEWER

LOCATED IN

DEREHAM ROAD

MH 3402 (IL 39.639)

TOP BANK: 43.37

ASSUMED IL: 42.17

STORMWATER

DISCHARGE TO

EXISTING DITCH

APPENDIX C

Create Consulting Page 1

15 Princes Street Kensington Forge

Norwich Storm Strategy Calcs

NR3 1AF

Date 24/04/2014 16:40 Designed by GH

File net 1 revised layout.mdx Checked by

Causeway Network 2013.1.1

STORM SEWER DESIGN by the Modified Rational Method

Design Criteria for Storm

©1982-2013 Micro Drainage Ltd

Pipe Sizes STANDARD Manhole Sizes STANDARD

FSR Rainfall Model - England and WalesReturn Period (years) 100

M5-60 (mm) 20.000Ratio R 0.401

Maximum Rainfall (mm/hr) 50Maximum Time of Concentration (mins) 30

Foul Sewage (l/s/ha) 0.000Volumetric Runoff Coeff. 0.750

Add Flow / Climate Change (%) 30Minimum Backdrop Height (m) 0.200Maximum Backdrop Height (m) 1.500

Min Design Depth for Optimisation (m) 1.200Min Vel for Auto Design only (m/s) 1.00

Min Slope for Optimisation (1:X) 500

Designed with Level Soffits

Network Design Table for Storm

PNPNPNPN LengthLengthLengthLength(m)(m)(m)(m)

FallFallFallFall(m)(m)(m)(m)

SlopeSlopeSlopeSlope(1:X)(1:X)(1:X)(1:X)

I.AreaI.AreaI.AreaI.Area(ha)(ha)(ha)(ha)

T.E.T.E.T.E.T.E.(mins)(mins)(mins)(mins)

BaseBaseBaseBaseFlow (l/s)Flow (l/s)Flow (l/s)Flow (l/s)

kkkk(mm)(mm)(mm)(mm)

HYDHYDHYDHYDSECTSECTSECTSECT

DIADIADIADIA(mm)(mm)(mm)(mm)

1.000 5.000 0.030 168.4 0.114 5.00 0.0 0.600 o 2251.001 25.000 0.148 168.9 0.000 0.00 0.0 0.600 o 3001.002 40.000 0.192 208.0 0.028 0.00 0.0 0.600 o 3001.003 10.000 0.130 76.9 0.000 0.00 0.0 0.600 o 3001.004 40.000 0.250 160.0 0.070 0.00 0.0 0.600 o 3001.005 30.000 0.297 101.2 0.055 0.00 0.0 0.600 o 300

2.000 10.000 0.067 149.3 0.017 5.00 0.0 0.600 o 300

1.006 15.000 0.075 200.0 0.000 0.00 0.0 0.600 o 3001.007 43.000 0.215 200.0 0.000 0.00 0.0 0.600 o 300

Network Results Table

PNPNPNPN RainRainRainRain(mm/hr)(mm/hr)(mm/hr)(mm/hr)

T.C.T.C.T.C.T.C.(mins)(mins)(mins)(mins)

US/ILUS/ILUS/ILUS/IL(m)(m)(m)(m)

Σ I.AreaΣ I.AreaΣ I.AreaΣ I.Area(ha)(ha)(ha)(ha)

Σ BaseΣ BaseΣ BaseΣ BaseFlow (l/s)Flow (l/s)Flow (l/s)Flow (l/s)

FoulFoulFoulFoul(l/s)(l/s)(l/s)(l/s)

Add FlowAdd FlowAdd FlowAdd Flow(l/s)(l/s)(l/s)(l/s)

VelVelVelVel(m/s)(m/s)(m/s)(m/s)

CapCapCapCap(l/s)(l/s)(l/s)(l/s)

FlowFlowFlowFlow(l/s)(l/s)(l/s)(l/s)

1.000 50.00 5.08 43.575 0.114 0.0 0.0 4.6 1.00 39.9 20.11.001 50.00 5.43 43.470 0.114 0.0 0.0 4.6 1.21 85.3 20.11.002 50.00 6.04 43.322 0.142 0.0 0.0 5.8 1.09 76.8 25.01.003 50.00 6.13 43.130 0.142 0.0 0.0 5.8 1.79 126.8 25.01.004 50.00 6.67 43.000 0.212 0.0 0.0 8.6 1.24 87.7 37.31.005 50.00 6.99 42.750 0.267 0.0 0.0 10.8 1.56 110.5 47.0

2.000 50.00 5.13 42.520 0.017 0.0 0.0 0.7 1.28 90.8 3.0

1.006 50.00 7.22 42.453 0.284 0.0 0.0 11.5 1.11 78.3 50.01.007 50.00 7.86 42.378 0.284 0.0 0.0 11.5 1.11 78.3 50.0

Free Flowing Outfall Details for Storm

OutfallOutfallOutfallOutfallPipe NumberPipe NumberPipe NumberPipe Number

OutfallOutfallOutfallOutfallNameNameNameName

C. LevelC. LevelC. LevelC. Level(m)(m)(m)(m)

I. LevelI. LevelI. LevelI. Level(m)(m)(m)(m)

MinMinMinMinI. LevelI. LevelI. LevelI. Level

(m)(m)(m)(m)

D,LD,LD,LD,L(mm)(mm)(mm)(mm)

WWWW(mm)(mm)(mm)(mm)

1.007 43.370 42.163 42.170 0 0

Create Consulting Page 2

15 Princes Street Kensington Forge

Norwich Storm Strategy Calcs

NR3 1AF

Date 24/04/2014 16:40 Designed by GH

File net 1 revised layout.mdx Checked by

Causeway Network 2013.1.1

Simulation Criteria for Storm

©1982-2013 Micro Drainage Ltd

Volumetric Runoff Coeff 0.750 Additional Flow - % of Total Flow 0.000Areal Reduction Factor 1.000 MADD Factor * 10m³/ha Storage 2.000

Hot Start (mins) 0 Inlet Coeffiecient 0.800Hot Start Level (mm) 0 Flow per Person per Day (l/per/day) 0.000

Manhole Headloss Coeff (Global) 0.500 Run Time (mins) 60Foul Sewage per hectare (l/s) 0.000 Output Interval (mins) 1

Number of Input Hydrographs 0 Number of Storage Structures 2Number of Online Controls 2 Number of Time/Area Diagrams 0

Number of Offline Controls 0 Number of Real Time Controls 0

Synthetic Rainfall Details

Rainfall Model FSR Profile Type SummerReturn Period (years) 100 Cv (Summer) 0.750

Region England and Wales Cv (Winter) 0.840M5-60 (mm) 20.000 Storm Duration (mins) 30

Ratio R 0.401

APPENDIX D

Pumping Station

Manhole

Inlet

Outfall

Sewage Treatment Works

Foul Sewer

Final Effluent

Decommissioned Sewer

(Colour denotes effluent type)


Surface SewerCombined Sewer




This plan is provided by Anglian Water pursuant its obligations under the Water Industry Act 1991 sections 198 or 199. It must be used in conjunction with any search results attached. The information on this plan is based on data currently recorded but position must be regarded as approximate. Service pipes, private sewers and drains are generally not shown. Users of this map are strongly advised to commission their own survey of the area shown on the plan before carrying out any works. The actual position of all apparatus MUST be established by trial holes. No liability whatsoever, including liability for negligence, is accepted by Anglian Water for any error or inaccuracy or omission, including the failure to accurately record, or record at all, the location of any water main, discharge pipe, sewer or disposal main or any item of apparatus. This information is valid for the date printed. The plan is produced by Anglian Water Services Limited from Ordnance Survey © Crown Copyright, 100018507. This map is to be used for the purposes of viewing the location of Anglian Water plant only. Any other uses of the map data or further copies is not permitted. This notice is not intended to exclude or restrict liability for death or personal injury resulting from negligence.

Date: 10/10/13 Scale: 1:1250 Data updated: 01/08/13Map Centre: 603348,311399(c) Crown Copyright and database rights 2011 Ordnance Survey 100018507 Wastewater Plan A3Our Ref: 76276 - 1

3098 Plummer

[email protected]

Private Sewer

Rising Main


Manhole Reference Liquid Type Cover Level Invert Level Depth to Invert

1402 F 42.416 40.666 1.75

1501 F 42.835 41.255 1.58

3401 F 42.459 40.069 2.39

3402 F 42.689 39.639 3.05

3403 F 42.727 39.987 2.74

3404 F - - -

4301 F 42.647 40.337 2.31

4302 F 42.791 40.581 2.21

4303 F 42.824 41.044 1.78



Our Ref: 76276 - 1

mattishall forge, kensington strategy development drainage

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