Site 7C, Edgar Mobbs Way, Northampton Flood Risk

Site 7C, Edgar Mobbs Way, Northampton

Flood Risk & Drainage Statement

Document Ref: EMW-BWB-HDG-XX-RP-D-003-S1-P2

Site 7C is a forthcoming development for Brackley Developments Ltd, located on Edgar Mobbs

Way in Northampton. This document has been prepared to support a Reserved Matters

application for four commercial units, as illustrated on Stephen George & Partners drawing

Waste Transfer Facility Site Layout 14-137-C001. The development area is approximately 1.1

hectares.

1. For the original drainage strategy approved under the Outline Planning permission, please

refer to the Nolan Associates drainage strategy document, dated December 2015, as

contained in the Planning application - N/2016/0015.

2. Floodplain mapping obtained from the Environment Agency website indicates that most of

the site is in Flood Zone 1, but with a small encroachment of Flood Zone 2 on the eastern site

boundary. See Figure 1 below.

Figure 1 – EA Floodplain Mapping Source: https://flood-map-for-planning.service.gov.uk on 5th July 2017

3. As set out in the approved Outline Planning drainage statement prepared by Nolan

Associates, flood water levels surrounding the site were obtained from the Environment

Agency, and it was concluded that no building floor level should be lower than 61.42m AOD

(which is 300mm higher than the 1 in 1000 flood plain level). The lowest building level for the

proposed development at Site 7C is 62.825m AOD. Therefore the proposed development is

sufficiently protected from flooding of the surrounding area.

4. The originally submitted outline planning proposal indicated surface water discharge to the

River Nene, however this was before Site 7C had been split into separate parcels. The

discharge route would now require access across third party land. Due to this, BWB met with

Tony Heath and Andrew Buckley of Anglian Water on 7th June 2017, where an agreement in-

principle was reached to discharge surface water runoff from the site to what at the time was

the final section of a highway drain network, which then connected to the Anglian Water

public sewer. Anglian Water have since agreed to a Section 102 Agreement with the sewer

being adopted by Anglian Water on 3rd January 2018.

https://flood-map-for-planning.service.gov.uk/

5. The site area is 1.1 hectares, with an approximate impermeable area of 7,350m² contributing

to surface water runoff. Run-off from the site in a ‘greenfield’ state would produce a QBAR

rate of 2.9 lit/sec. However, due to how the low flow would correlate to a small diameter

control size, and the maintenance/blockage issues which come with small control diameters,

a discharge rate of 5 lit/sec is proposed, which is accepted in the industry as an appropriate

minimum flow rate to avoid maintenance/blockage issues.

6. A discharge restriction of 5 lit/sec maximum discharge from the site was also agreed upon

with Anglian Water. In order to achieve this discharge rate, a below ground attenuation tank

and flow control device will be situated within the site.

7. Foul water will discharge as originally indicated in the Outline drainage strategy to the public

sewer in Edgar Mobbs Way. A foul penstock within the site will be installed to enable isolation

of the yard areas of the site from the external drainage network in the event of a fire requiring

firefighting measures.

8. Both surface and foul water connections will be made under S106 of the water industry act

1990, and with agreement from Anglian Water.

9. The proposed drainage strategy drawing is contained within Appendix A for information.

10. Advice from Northamptonshire County Council, who are the Lead Local Flood Authority,

indicated that there is a requirement to ensure that all surface water runoff up to a 1 in 200

year storm event is contained on site including an allowance for climate change. To this end

the drainage network and site levels have been designed to contain and flooding up to this

storm event within the site.

11. The attached Microdrainage WinDes storm simulations set out in Appendix B show the critical

storm event for the drainage and flow control is indicated as a 360 minute storm event.

Following Ciria C753 Guidance all critical storm events over 30 minute will be reviewed using

FEH data, as these storm events have a larger bearing on storage volumes whereas all critical

storm events of 30 minute or less will primarily rely upon FSR data. Additionally it should be

noted that using a rural runoff calculation it can be shown that the existing greenfield site

would have a discharge rate of 12 lit/sec for a 200 year storm event. As a result, the proposed

discharge from site at 5 lit/sec to the Anglian Water sewer system would be a 7 lit/sec

reduction, and as a result discharge from the site is significantly reduced from the existing 200

year storm event rate.

12. The Microdrainage results show there is some minor flooding during the 100 year storm event

and slightly more flooding (circa 80m3) during the 200 year storm event. Flooding within the

site during these extreme storms is to be expected and the anticipated volumes of flooding

would be contained within the car park and refuse vehicle parking areas. The flooding would

then re-enter the drainage network once the peak storm has passed.

13. Prior to considering a gravity storm water connection to the existing public sewer, infiltration

methods were reviewed. However, due to the underlying Made Ground and contaminants,

infiltration methods were ruled out to avoid leaching of contaminants. This approach is

consistent with the drainage strategy approved under the Outline Planning permission.

14. Where possible, we have tried to incorporate SuDs features within the site drainage scheme.

Filter drains will be situated along the northern site boundary and all surface water chambers

will be catchpits to help ensure fine particle settlement prior to entry into the drainage

network. High risk areas are treated separately to the surrounding yard. Cut off drains will be

installed at the level access door to the Waste transfer building with silt traps to enable spills

within the building to be contained. The fuel bay has cut off drains draining this area to a

forecourt separator prior to discharge into the foul network. The wash down area will pass

through a wash down separator prior to discharging into the foul network. It will be possible to

isolate these areas in the event of firefighting through the use of a penstock downstream of

the yard area.

15. All surface water drainage from the service yard will pass through a full retention separator

prior to mixing with roof runoff. All parking and RCV standing areas will pass through a full

retention separator prior to mixing with roof runoff. This means that the all external surface

water run-off will pass through a full retention separator to reduce risk from oil spills or

hydrocarbon contamination.

16. A hydraulic model of the proposed drainage network has been produced in Microdrainage

WinDES software. The model indicates that the development drainage network and storage

has been sized to ensure no flooding leaves site in any storm event up to and including the 1

in 200 year event or the 1:100yr plus 20% for Climate Change.

17. In summary, the above drainage strategy demonstrates that an effective level of treatment

for the surface water drainage has been adopted for the site and appropriately designed

storage facilities for storm water prevents flooding to third party land or the proposed new

buildings. Flood risk from the surrounding floodplain has no effect on the development due to

the 1m level difference between the proposed buildings and the 1 in 1000 year flood level.

BWB Consulting Ltd

16th October 2017

Appendix A

EMW-BWB-XX-XX-DR-D-500_Proposed Drainage Strategy

Car Parking - 44 spaces

RCV Parking

6 spaces

R

e

t

a

i

n

i

n

g

W

a

l

l

Retaining

Wall

Retaining Wall

Retaining W

all

Waste Transfer Building

Water

Tank

Pum

p

House

Office/W

elfare Building

(Supplied and installed by Veolia)

Washbay

Weighbridge

RCV Parking - 15 spaces

Weighbridge

Cycles

T

a

n

k

s

F

u

e

l

b

a

y

RCV Parking

3 spaces

225m

m Ø

AW 0151

CL 60.42

IL 58.60

AW 9100

CL 63.660

IL 60.215

S05 (R.E)

CL 62.785

IL 61.735 (150Ø)

Filter Drain 150Ø @ 1:150>>

EX

CL 60.67

IL 59.02

1

5

0

Ø

@

1

:

3

0

>

>

CL 60.80

IL 59.375

1

5

0

Ø

@

1

:

1

7

1

>

>

SURFACE WATER

CONNECTION TO EXISTING

HIGHWAY MH

SECTION OF EXISTING

HIGHWAY DRAIN TO BE

ADOPTED BY ANGLIAN

WATER UNDER A S102

AGREEMENT

CONNECTION TO EXISTING

FOUL STUB. PRECISE

POSITION AND LEVEL OF TO

BE CONFIRMED ON SITE

BEFORE WORKS COMMENCE.

FINDINGS TO BE REPORTED

TO BWB FOR CONSIDERATION.

CONTRACTOR TO APPLY FOR

SECTION 106 APPLICATION

FOR FOUL CONNECTION. NOTE

APPROVAL CAN TAKE 28 DAYS

FROM RECEIPT OF

APPLICATION

CONTRACTOR TO APPLY FOR

SECTION 106 APPLICATION

FOR STORM CONNECTION.

NOTE APPROVAL CAN TAKE 28

DAYS FROM RECEIPT OF

APPLICATION

Linear drain situated

at boundary of

adopted highway

S01

1200ØPCC CATCHPIT

CL 62.935

IL 61.585 (150Ø)

F9

1200ØPCC

CL 62.000

IL 59.500(150Ø)

150Ø @ 1:75>>

S04

1050ØPCC CATCHPIT

CL 62.790

IL 61.310 (150Ø)

S14

1200ØPCC CATCHPIT

CL 61.95

IL 59.950(150Ø)

PENSTOCK OR

SHUT-OFF VALVE

FITTED TO OUTLET

PIPE

Pop-Up positions

TBC

63

.0

23

S02

1200ØPCC CATCHPIT

CL 62.840

IL 60.795(150Ø)

IL 60.720(225Ø)

S06

1200ØPCC CATCHPIT

CL 62.805

IL 60.660(225Ø)

S12

1200Ø PCC CATCHPIT

CL 62.740

IL 61.180(225Ø)

PENSTOCK OR SHUT

OFF VALVE TO ISOLATE

YARD DRAINAGE

[AB]

[OB]

Pop-Up positions

TBC

Full

retention

separator

Full

retention

separator

Separator for vehicle

washdown area

Petrol forecourt separator

for fuel bay area

Fuel area sump unit

for silt collection

S09

1200Ø PCC CATCHPIT

CL 61.975

IL 60.670 (150Ø)

Linear drain [F900]

S07

1200ØPCC CATCHPIT

CL 62.725

IL 60.300(225Ø)

IL 60.225(300Ø)

S10

1200ØPCC CATCHPIT

CL 62.125

IL 60.655(225Ø)

S08

1200ØPCC CATCHPIT

CL 62.235

IL 60.450(150Ø)

IL 60.375(225Ø)

S03

1200ØPCC CATCHPIT

CL 62.810

IL 60.715(375Ø)

F1

1200ØPCC

CL 62.890

IL 61.540(150Ø)

F2

1200ØPCC

CL 62.795

IL 61.420(150Ø)

F3

1200ØPCC

CL 62.795

IL 61.155(150Ø)

F4

1200ØPCC

CL 62.685

IL 60.980(150Ø)

F5

PENSTOCK

1200ØPCC

CL 62.580

IL 60.850(150Ø)

150Ø @ 1:133>>

1

5

0

Ø

@

1

:

1

3

3

>

>

1

5

0

Ø

@

1

:

1

3

3

>

>

150Ø @ 1:133>>

150Ø

@

1:1

33>

>

1

5

0

Ø

@

1

:

1

1

>

>

150Ø

@

1:1

50>

>

Hydro-brake

flow control.

Limited to 5l/s

S13 (Control Chamber)

1200ØPCC CATCHPIT

CL 62.020

IL 60.000(150Ø)

500m³

CL 62.040

TOT 61.000

IL 60.000

Channel drain [D400]

Ch

an

ne

l d

ra

in

[D

40

0]

Mo

no

lith

ic

ro

ad

d

ra

in

[F

90

0]

Lin

ea

r d

ra

in

[F

90

0]

F6

1200ØPCC

CL 62.295

IL 60.750(150Ø)

F7

1200ØPCC

CL 62.620

IL 61.315(150Ø)

F8

1200ØPCC

CL 62.765

IL 61.415(150Ø)

S11

1200ØPCC CATCHPIT

CL 62.520

IL 60.160(300Ø)

Silt trap

22

5Ø

@

1

:1

67

>>

150Ø

@

1:150>

>

15

0Ø

@

1

:1

50

>>

<

<

150Ø

@

1:150

<

<

2

2

5

Ø

@

1

:5

0

<<225Ø @ 1:167

225Ø @ 1:39>>

30

0Ø

@ 1

:2

38

>>

22

5Ø

@

1

:1

67

>>

1

5

0

Ø

@

1

:

3

4

>

>

1

5

0

Ø

@

1

:1

3

3

>

>

Storage volume subject to

confirmation. Must ensure

1:200 yr storm event is

stored on-site

Linear drain [F900]

Fuel area cut off

drain

EXISTING PUBLIC SURFACE WATER SEWER (ANGLIAN WATER)

EXISTING HIGHWAY SURFACE WATER SEWER (NORTHAMPTONSHIRE COUNTY COUNCIL)

PROPOSED PRIVATE SURFACE WATER DRAIN

PROPOSED FILTER DRAIN WITH IMPERMEABLE LINER

PROPOSED CHANNEL DRAINAGE

EXISTING FOUL WATER SEWER

PROPOSED FOUL WATER DRAIN

PROPOSED CLASS 1 BYPASS INTERCEPTOR

PROPOSED SURFACE WATER MH

PROPOSED FOUL MH

PROPOSED FILTER DRAIN MH

PROPOSED GULLY

KEY:

Project - Originator - Zone - Level - Type - Role - Number Status RevDrawing Status

Drawing TitleProject TitleClient

BWB Ref: Date: Scale@A1:

Drawn: Reviewed:

Rev Date RevDrw

ISSUES & REVISIONS

Details of issue / revision

CONSULTANCY | ENVIRONMENTINFRASTRUCTURE | BUILDINGS

Manchester | 0161 233 4260

Nottingham | 0115 924 1100

Leeds | 0113 233 8000

London | 020 7234 9122

Birmingham | 0121 233 3322

www.bwbconsulting.com© Copyright BWB Consulting Ltd

S8EMW-BWB-DDG-XX-DR-C-500 P1PLANNING

PROPOSED DRAINAGE

STRATEGY

EDGAR MOBBS WAY

NORTHAMPTON

R. Stacey K. James

NTH 2325 1:25027.06.17

1. Do not scale this drawing. All dimensions must be checked/ verified

on site. If in doubt ask.

2. This drawing is to be read in conjunction with all relevant architects,

engineers and specialists drawings and specifications.

3. All dimensions in millimetres unless noted otherwise. All levels in

metres unless noted otherwise.

4. Any discrepancies noted on site are to be reported to the engineer

immediately.

Notes Key Plan

Y:\NTH\NTH2325_Edgar Mobbs Way, Northampton\02. Project Delivery\01. WIP\Drawings\EMW-BWB-DDG-XX-DR-C-500_Drainage strategy D2 T5.dwg

Notes

1. Do not scale this drawing. All dimensions must be checked/ verified

on site. If in doubt ask.

2. This drawing is to be read in conjunction with all relevant architects,

engineers and specialists drawings and specifications.

3. All dimensions in millimetres unless noted otherwise. All levels in

metres unless noted otherwise.

4. Any discrepancies noted on site are to be reported to the engineer

immediately.

AP

PR

OX

Drainage Notes

1. All adoptable surface and foul water drainage works to be carried

out in strict accordance with 'Sewers for Adoption 7th edition' and

any specific requirements of the adopting authority.

2. All adoptable highway drainage works to be carried out in strict

accordance with the Local Highway Authority requirements and the

DfT MCHW specification for highway works.

3. All private drainage works are to be carried out in accordance with

Building Regulations Part H, BS EN 752, the Civil Engineering

Specification for the Water Industry and, where provided, the BWB

Drainage Specification.

4. Where applicable the contractor shall allow free and full access to

the drainage works for the local authority, highway authority,

drainage authority or the overseeing organisation.

5. The exact position, level, line, size and use of existing drainage is to

be confirmed on site. Any discrepancies to be reported to the

engineer prior to the commencement of works.

6. For new connections to existing manholes, existing benching is to be

broken out and reformed to suit. Concrete/brick surround to be made

good.

7. All temporary works associated with the construction of the drainage

works shall be the responsibility of the contractor, including the

protection of any uncovered/shallow pipework against construction

traffic.

8. The Contractor is responsible for obtaining and paying for all

necessary permissions to enable construction of the works to be

undertaken, including but not limited to licences for street works and

connections to existing sewers. This includes Section 106

applications when connecting directly or indirectly to the public

sewerage network (complete application to be made at least 3

weeks prior to the planned outfall construction works).

9. Any damage caused to existing footways, roads or other third party

property to be made good.

10. Under roads and external paved areas all materials within 450mm of

finished levels to be non-frost susceptable. Reinstatements shall be

undertaken in accordance with the BWB standard detail.

11. All proposed chamber covers are to be marked permanently with

“SWS” (or equiv.) on surface water sewers and “FWS” (or equiv.) on

foul sewers. all covers to be in accordance with BS EN 124.

12. Unless noted otherwise, all lateral connections are to be installed

with level soffits to the diameters and gradients shown on the layout

drawing. Any pipe bends should be provided to suit the direction of

flow & no pipework should be downsized in the direction of flow.

13. The number and location of all RWPs is shown indicatively only. To

be confirmed by Architect / M&E contractor prior to commencement

of works.

14. Foul water 'pop up positions' are shown indicatively only, to be

confirmed by the Architect / M&E contractor prior to commencement

of works. Refer to Architect plans for setting out of internal foul pop

up positions.

15. All RWPs and SVPs to be fitted with rodable access plates. All foul

drains to have rodable access.

16. Above ground drainage details to be designed/confirmed by the

Architect/M&E contractor, including ventilation of the foul drainage

system.

17. Proposed drainage passing through new foundations to be sleeved

with cast-in oversized pipework.

18. All specialist/proprietary products such as separators, attenuation

tanks, channel drains, soakaways, package pumping station and

water treatment units to be installed as per the manufacturer's

installation details and specifications.

S12

Contractor to review and action

the project CDM Risk Register

and the Remediation Strategy,

with specific reference to

ground related risks.

Caution

C1

P1 16.10.18 Updated to Waste Transfer Facility site plan RDSMC

AutoCAD SHX Text

61.42

AutoCAD SHX Text

MO

AutoCAD SHX Text

5000

AutoCAD SHX Text

EB

AutoCAD SHX Text

EB

AutoCAD SHX Text

P

AutoCAD SHX Text

60.41

AutoCAD SHX Text

2

AutoCAD SHX Text

I/R Ht=1.3m

Appendix B

Microdrainage WinDES Calculations

BWB Consulting Ltd Page 15th Floor, Waterfront House Edgar Mobbs Way35 Station StreetNottingham, NG2 3DQDate 17/10/2018 13:12 Designed by david.grayFile EDGAR MOBBS FEH 16.10.18.MDX Checked byXP Solutions Network 2017.1.2

STORM SEWER DESIGN by the Modified Rational Method

Design Criteria for Storm

©1982-2017 XP Solutions

Pipe Sizes STANDARD Manhole Sizes STANDARD

FEH Rainfall ModelReturn Period (years) 200FEH Rainfall Version 1999

Site Location GB 473950 260050 SP 73950 60050C (1km) -0.026D1 (1km) 0.332D2 (1km) 0.266D3 (1km) 0.268E (1km) 0.306F (1km) 2.527

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

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

PIMP (%) 100Add Flow / Climate Change (%) 0Minimum 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) 1.00Min Slope for Optimisation (1:X) 500

Designed with Level Soffits

Time Area Diagram for Storm

Time(mins)

Area(ha)

Time(mins)

Area(ha)

Time(mins)

Area(ha)

0-4 0.320 4-8 0.410 8-12 0.005

Total Area Contributing (ha) = 0.735

Total Pipe Volume (m³) = 11.207

Network Design Table for Storm

« - Indicates pipe capacity < flow

PN Length(m)

Fall(m)

Slope(1:X)

I.Area(ha)

T.E.(mins)

BaseFlow (l/s)

k(mm)

HYDSECT

DIA(mm)

Section Type AutoDesign

S1.000 36.462 0.243 150.0 0.039 5.00 0.0 0.600 o 150 Pipe/ConduitS1.001 28.002 0.187 150.0 0.039 0.00 0.0 0.600 o 150 Pipe/ConduitS1.002 17.679 0.118 149.8 0.000 0.00 0.0 0.600 o 150 Pipe/Conduit

Network Results Table

PN Rain(mm/hr)

T.C.(mins)

US/IL(m)

Σ I.Area(ha)

Σ BaseFlow (l/s)

Foul(l/s)

Add Flow(l/s)

Vel(m/s)

Cap(l/s)

Flow(l/s)

S1.000 50.00 5.74 61.735 0.039 0.0 0.0 0.0 0.82 14.5 5.3S1.001 50.00 6.31 61.351 0.078 0.0 0.0 0.0 0.82 14.5 10.6S1.002 50.00 6.67 60.977 0.078 0.0 0.0 0.0 0.82 14.5 10.6


Network Design Table for Storm


PN Length(m)

Fall(m)

Slope(1:X)

I.Area(ha)

T.E.(mins)

BaseFlow (l/s)

k(mm)

HYDSECT

DIA(mm)

Section Type AutoDesign

S1.003 12.992 0.087 149.3 0.000 0.00 0.0 0.600 o 150 Pipe/Conduit

S2.000 29.816 0.199 149.8 0.039 5.00 0.0 0.600 o 150 Pipe/ConduitS2.001 29.816 0.199 149.8 0.039 0.00 0.0 0.600 o 150 Pipe/Conduit


S3.000 32.541 0.217 150.0 0.051 5.00 0.0 0.600 o 150 Pipe/Conduit


S3.001 12.739 0.076 167.6 0.047 0.00 0.0 0.600 o 225 Pipe/Conduit

S1.006 15.351 0.051 300.0 0.061 0.00 0.0 0.600 o 300 Pipe/Conduit


S1.007 8.051 0.027 300.0 0.000 0.00 0.0 0.600 o 375 Pipe/ConduitS1.008 10.851 0.036 301.4 0.000 0.00 0.0 0.600 o 375 Pipe/ConduitS1.009 7.475 0.050 149.5 0.000 0.00 0.0 0.600 o 150 Pipe/ConduitS1.010 27.994 0.187 149.7 0.000 0.00 0.0 0.600 o 150 Pipe/Conduit

Network Results Table

PN Rain(mm/hr)

T.C.(mins)

US/IL(m)

Σ I.Area(ha)

Σ BaseFlow (l/s)

Foul(l/s)

Add Flow(l/s)

Vel(m/s)

Cap(l/s)

Flow(l/s)

S1.003 50.00 6.94 60.859 0.078 0.0 0.0 0.0 0.82 14.5 10.6

S2.000 50.00 5.61 61.585 0.039 0.0 0.0 0.0 0.82 14.5 5.3S2.001 50.00 6.21 61.187 0.078 0.0 0.0 0.0 0.82 14.5 10.6

S1.004 50.00 7.10 60.697 0.156 0.0 0.0 0.0 1.01 40.2 21.1S1.005 50.00 7.33 60.637 0.156 0.0 0.0 0.0 1.01 40.1 21.1

S3.000 50.00 5.66 60.625 0.051 0.0 0.0 0.0 0.82 14.5 6.9

S4.000 50.00 5.12 60.700 0.106 0.0 0.0 0.0 1.01 40.1 14.4S4.001 50.00 5.35 60.657 0.171 0.0 0.0 0.0 1.01 40.1 23.2

S3.001 50.00 5.87 60.408 0.269 0.0 0.0 0.0 1.01 40.0 36.4

S1.006 50.00 7.61 60.332 0.486 0.0 0.0 0.0 0.90 63.8« 65.8

S5.000 50.00 5.20 61.225 0.249 0.0 0.0 0.0 1.01 40.1 33.7S5.001 50.00 5.75 61.151 0.249 0.0 0.0 0.0 1.01 40.1 33.7

S1.007 50.00 7.74 60.129 0.735 0.0 0.0 0.0 1.04 115.0 99.5S1.008 50.00 7.92 60.102 0.735 0.0 0.0 0.0 1.04 114.7 99.5S1.009 50.00 8.07 60.003 0.735 0.0 0.0 0.0 0.82 14.5« 99.5S1.010 50.00 8.64 59.950 0.735 0.0 0.0 0.0 0.82 14.5« 99.5


PIPELINE SCHEDULES for Storm

Upstream Manhole


PN HydSect

Diam(mm)

MHName

C.Level(m)

I.Level(m)

D.Depth(m)

MHConnection

MH DIAM., L*W(mm)

S1.000 o 150 S05 62.600 61.735 0.715 Open Manhole 1200S1.001 o 150 S04A 62.600 61.351 1.099 Open Manhole 1200S1.002 o 150 S04 62.790 60.977 1.663 Open Manhole 1200S1.003 o 150 S03 62.785 60.859 1.776 Open Manhole 1200

S2.000 o 150 S01 62.935 61.585 1.200 Open Manhole 1200S2.001 o 150 S6 62.935 61.187 1.598 Open Manhole 1200

S1.004 o 225 S02 62.840 60.697 1.918 Open Manhole 1200S1.005 o 225 S6 62.725 60.637 1.863 Open Manhole 1200

S3.000 o 150 S09 61.900 60.625 1.125 Open Manhole 1200

S4.000 o 225 SACO 61.990 60.700 1.065 Open Manhole 1200S4.001 o 225 S10 62.235 60.657 1.353 Open Manhole 1200

S3.001 o 225 S08 62.235 60.408 1.602 Open Manhole 1200

S1.006 o 300 S7 62.900 60.332 2.268 Open Manhole 1200

S5.000 o 225 SACO 62.680 61.225 1.230 Open Manhole 1200S5.001 o 225 S12 62.740 61.151 1.364 Open Manhole 1200

S1.007 o 375 S11 62.575 60.129 2.071 Open Manhole 1350S1.008 o 375 S12 Attenuation 62.470 60.102 1.993 Open Manhole 1350

Downstream Manhole

PN Length(m)

Slope(1:X)

MHName

C.Level(m)

I.Level(m)

D.Depth(m)

MHConnection

MH DIAM., L*W(mm)

S1.000 36.462 150.0 S04A 62.600 61.492 0.958 Open Manhole 1200S1.001 28.002 150.0 S04 62.790 61.164 1.476 Open Manhole 1200S1.002 17.679 149.8 S03 62.785 60.859 1.776 Open Manhole 1200S1.003 12.992 149.3 S02 62.840 60.772 1.918 Open Manhole 1200

S2.000 29.816 149.8 S6 62.935 61.386 1.399 Open Manhole 1200S2.001 29.816 149.8 S02 62.840 60.988 1.702 Open Manhole 1200


S3.000 32.541 150.0 S08 62.235 60.408 1.677 Open Manhole 1200


S3.001 12.739 167.6 S7 62.900 60.332 2.343 Open Manhole 1200

S1.006 15.351 300.0 S11 62.575 60.281 1.994 Open Manhole 1350


S1.007 8.051 300.0 S12 Attenuation 62.470 60.102 1.993 Open Manhole 1350S1.008 10.851 301.4 S13 Flow Control 62.000 60.066 1.559 Open Manhole 1350


PIPELINE SCHEDULES for Storm

Upstream Manhole


PN HydSect

Diam(mm)

MHName

C.Level(m)

I.Level(m)

D.Depth(m)

MHConnection

MH DIAM., L*W(mm)

S1.009 o 150 S13 Flow Control 62.000 60.003 1.847 Open Manhole 1350S1.010 o 150 S14 61.950 59.950 1.850 Open Manhole 1200

Downstream Manhole

PN Length(m)

Slope(1:X)

MHName

C.Level(m)

I.Level(m)

D.Depth(m)

MHConnection

MH DIAM., L*W(mm)

S1.009 7.475 149.5 S14 61.950 59.953 1.847 Open Manhole 1200S1.010 27.994 149.7 S 60.560 59.763 0.647 Open Manhole 0


Area Summary for Storm


PipeNumber

PIMPType

PIMPName

PIMP(%)

GrossArea (ha)

Imp.Area (ha)

Pipe Total(ha)

1.000 - - 100 0.039 0.039 0.0391.001 - - 100 0.039 0.039 0.0391.002 - - 100 0.000 0.000 0.0001.003 - - 100 0.000 0.000 0.0002.000 - - 100 0.039 0.039 0.0392.001 - - 100 0.039 0.039 0.0391.004 - - 100 0.000 0.000 0.0001.005 - - 100 0.000 0.000 0.0003.000 - - 100 0.051 0.051 0.0514.000 - - 100 0.106 0.106 0.1064.001 - - 100 0.065 0.065 0.0653.001 - - 100 0.047 0.047 0.0471.006 - - 100 0.061 0.061 0.0615.000 - - 100 0.249 0.249 0.2495.001 - - 100 0.000 0.000 0.0001.007 - - 100 0.000 0.000 0.0001.008 - - 100 0.000 0.000 0.0001.009 - - 100 0.000 0.000 0.0001.010 - - 100 0.000 0.000 0.000

Total Total Total0.735 0.735 0.735

Simulation Criteria for Storm

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 Offline Controls 0 Number of Time/Area Diagrams 0Number of Online Controls 1 Number of Storage Structures 3 Number of Real Time Controls 0

Synthetic Rainfall Details

Rainfall Model FSR Profile Type SummerReturn Period (years) 200 Cv (Summer) 0.750

Region England and Wales Cv (Winter) 0.840M5-60 (mm) 20.800 Storm Duration (mins) 30

Ratio R 0.450


Online Controls for Storm


Hydro-Brake® Optimum Manhole: S13 Flow Control, DS/PN: S1.009, Volume (m³): 3.9

Unit Reference MD-SHE-0092-5000-2000-5000Design Head (m) 2.000

Design Flow (l/s) 5.0Flush-Flo™ CalculatedObjective Minimise upstream storage

Application SurfaceSump Available YesDiameter (mm) 92

Invert Level (m) 60.003Minimum Outlet Pipe Diameter (mm) 150Suggested Manhole Diameter (mm) 1200

Control Points Head (m) Flow (l/s) Control Points Head (m) Flow (l/s)

Design Point (Calculated) 2.000 5.0 Kick-Flo® 0.816 3.3Flush-Flo™ 0.398 4.1 Mean Flow over Head Range - 3.9

The hydrological calculations have been based on the Head/Discharge relationship for the Hydro-Brake®Optimum as specified. Should another type of control device other than a Hydro-Brake Optimum® beutilised then these storage routing calculations will be invalidated

Depth (m) Flow (l/s) Depth (m) Flow (l/s) Depth (m) Flow (l/s) Depth (m) Flow (l/s) Depth (m) Flow (l/s)

0.100 2.9 0.800 3.4 2.000 5.0 4.000 6.9 7.000 9.00.200 3.8 1.000 3.6 2.200 5.2 4.500 7.3 7.500 9.30.300 4.1 1.200 3.9 2.400 5.4 5.000 7.7 8.000 9.60.400 4.1 1.400 4.2 2.600 5.6 5.500 8.0 8.500 9.90.500 4.1 1.600 4.5 3.000 6.0 6.000 8.4 9.000 10.20.600 4.0 1.800 4.8 3.500 6.5 6.500 8.7 9.500 10.4


Storage Structures for Storm


Filter Drain Manhole: S05, DS/PN: S1.000

Infiltration Coefficient Base (m/hr) 0.00000 Pipe Diameter (m) 0.225Infiltration Coefficient Side (m/hr) 0.00000 Pipe Depth above Invert (m) 0.000

Safety Factor 2.0 Number of Pipes 1Porosity 0.30 Slope (1:X) 150.0

Invert Level (m) 61.735 Cap Volume Depth (m) 0.000Trench Width (m) 0.5 Cap Infiltration Depth (m) 0.000Trench Length (m) 40.0

Filter Drain Manhole: S04A, DS/PN: S1.001

Infiltration Coefficient Base (m/hr) 0.00000 Pipe Diameter (m) 0.225Infiltration Coefficient Side (m/hr) 0.00000 Pipe Depth above Invert (m) 0.000

Safety Factor 2.0 Number of Pipes 1Porosity 0.30 Slope (1:X) 150.0

Invert Level (m) 61.475 Cap Volume Depth (m) 0.000Trench Width (m) 0.5 Cap Infiltration Depth (m) 0.000Trench Length (m) 37.5

Cellular Storage Manhole: S13 Flow Control, DS/PN: S1.009

Invert Level (m) 60.003 Safety Factor 2.0Infiltration Coefficient Base (m/hr) 0.00000 Porosity 1.00Infiltration Coefficient Side (m/hr) 0.00000

Depth (m) Area (m²) Inf. Area (m²) Depth (m) Area (m²) Inf. Area (m²)

0.000 500.0 0.0 1.001 0.0 0.01.000 500.0 0.0 2.368 0.0 0.0


100 year Return Period Summary of Critical Results by Maximum Level (Rank 1) for Storm


Simulation CriteriaAreal Reduction Factor 1.000 Additional Flow - % of Total Flow 0.000

Hot Start (mins) 0 MADD Factor * 10m³/ha Storage 2.000Hot Start Level (mm) 0 Inlet Coeffiecient 0.800

Manhole Headloss Coeff (Global) 0.500 Flow per Person per Day (l/per/day) 0.000Foul Sewage per hectare (l/s) 0.000


Synthetic Rainfall DetailsRainfall Model FEH D3 (1km) 0.268

FEH Rainfall Version 1999 E (1km) 0.306Site Location GB 473950 260050 SP 73950 60050 F (1km) 2.527

C (1km) -0.026 Cv (Summer) 0.750D1 (1km) 0.332 Cv (Winter) 0.840D2 (1km) 0.266

Margin for Flood Risk Warning (mm) 300.0Analysis Timestep 2.5 Second Increment (Extended)

DTS Status ONDVD Status OFF

Inertia Status OFF

Profile(s) Summer and WinterDuration(s) (mins) 60, 120, 180, 240, 360, 480, 600, 720, 960, 1440,

2160, 2880Return Period(s) (years) 100, 200

Climate Change (%) 20, 20

PNUS/MHName Storm

ReturnPeriod

ClimateChange

First (X)Surcharge

First (Y)Flood

First (Z)Overflow

OverflowAct.

S1.000 S05 60 Summer 100 +20% 100/60 SummerS1.001 S04A 60 Summer 100 +20% 100/60 SummerS1.002 S04 60 Summer 100 +20% 100/60 SummerS1.003 S03 60 Summer 100 +20% 100/60 SummerS2.000 S01 60 Summer 100 +20% 100/60 Summer 200/60 SummerS2.001 S6 60 Summer 100 +20% 100/60 SummerS1.004 S02 60 Summer 100 +20% 100/60 SummerS1.005 S6 60 Summer 100 +20% 100/60 SummerS3.000 S09 60 Summer 100 +20% 100/60 Summer 100/60 SummerS4.000 SACO 60 Summer 100 +20% 100/60 Summer 100/60 SummerS4.001 S10 60 Summer 100 +20% 100/60 SummerS3.001 S08 60 Summer 100 +20% 100/60 SummerS1.006 S7 60 Summer 100 +20% 100/60 SummerS5.000 SACO 60 Summer 100 +20% 100/60 Summer 100/60 SummerS5.001 S12 60 Summer 100 +20% 100/60 SummerS1.007 S11 60 Summer 100 +20% 100/60 SummerS1.008 S12 Attenuation 720 Winter 100 +20% 100/60 SummerS1.009 S13 Flow Control 720 Winter 100 +20% 100/60 Summer 200/360 WinterS1.010 S14 2880 Summer 100 +20%




PNUS/MHName

Water Level(m)

SurchargedDepth(m)

FloodedVolume(m³)

Flow /Cap.

Overflow(l/s)

PipeFlow(l/s) Status

LevelExceeded

S1.000 S05 62.092 0.207 0.000 0.88 12.3 SURCHARGEDS1.001 S04A 62.021 0.520 0.000 1.40 19.3 SURCHARGEDS1.002 S04 61.801 0.674 0.000 1.54 20.8 SURCHARGEDS1.003 S03 61.662 0.653 0.000 1.63 21.5 SURCHARGEDS2.000 S01 62.445 0.710 0.000 0.96 13.4 SURCHARGED 1S2.001 S6 62.256 0.919 0.000 1.84 25.6 SURCHARGEDS1.004 S02 61.568 0.646 0.000 1.21 40.4 SURCHARGEDS1.005 S6 61.491 0.629 0.000 1.19 41.6 SURCHARGEDS3.000 S09 61.903 1.128 2.537 1.55 21.5 FLOOD 12S4.000 SACO 61.994 1.069 3.546 1.42 42.6 FLOOD 9S4.001 S10 61.975 1.093 0.000 1.58 55.4 FLOOD RISKS3.001 S08 61.801 1.168 0.000 2.40 82.9 SURCHARGEDS1.006 S7 61.405 0.773 0.000 2.55 136.7 SURCHARGEDS5.000 SACO 62.683 1.233 2.665 2.53 87.0 FLOOD 3S5.001 S12 62.215 0.839 0.000 2.30 86.7 SURCHARGEDS1.007 S11 61.071 0.567 0.000 2.77 222.8 SURCHARGEDS1.008 S12 Attenuation 61.000 0.523 0.000 0.43 36.8 SURCHARGEDS1.009 S13 Flow Control 60.999 0.846 0.000 0.33 4.1 SURCHARGED 3S1.010 S14 60.006 -0.094 0.000 0.30 4.1 OK




Simulation CriteriaAreal Reduction Factor 1.000 Additional Flow - % of Total Flow 0.000

Hot Start (mins) 0 MADD Factor * 10m³/ha Storage 2.000Hot Start Level (mm) 0 Inlet Coeffiecient 0.800

Manhole Headloss Coeff (Global) 0.500 Flow per Person per Day (l/per/day) 0.000Foul Sewage per hectare (l/s) 0.000


Synthetic Rainfall DetailsRainfall Model FEH D3 (1km) 0.268

FEH Rainfall Version 1999 E (1km) 0.306Site Location GB 473950 260050 SP 73950 60050 F (1km) 2.527

C (1km) -0.026 Cv (Summer) 0.750D1 (1km) 0.332 Cv (Winter) 0.840D2 (1km) 0.266

Margin for Flood Risk Warning (mm) 300.0Analysis Timestep 2.5 Second Increment (Extended)

DTS Status ONDVD Status OFF

Inertia Status OFF

Profile(s) Summer and WinterDuration(s) (mins) 60, 120, 180, 240, 360, 480, 600, 720, 960, 1440,

2160, 2880Return Period(s) (years) 100, 200

Climate Change (%) 20, 20

PNUS/MHName Storm

ReturnPeriod

ClimateChange

First (X)Surcharge

First (Y)Flood

First (Z)Overflow

OverflowAct.

Water Level(m)

S1.000 S05 60 Winter 200 +20% 100/60 Summer 62.408S1.001 S04A 60 Winter 200 +20% 100/60 Summer 62.311S1.002 S04 360 Winter 200 +20% 100/60 Summer 62.024S1.003 S03 360 Winter 200 +20% 100/60 Summer 62.018S2.000 S01 60 Summer 200 +20% 100/60 Summer 200/60 Summer 62.935S2.001 S6 60 Summer 200 +20% 100/60 Summer 62.716S1.004 S02 360 Winter 200 +20% 100/60 Summer 62.013S1.005 S6 360 Winter 200 +20% 100/60 Summer 62.009S3.000 S09 720 Winter 200 +20% 100/60 Summer 100/60 Summer 61.957S4.000 SACO 60 Summer 200 +20% 100/60 Summer 100/60 Summer 62.003S4.001 S10 600 Winter 200 +20% 100/60 Summer 61.996S3.001 S08 360 Winter 200 +20% 100/60 Summer 61.994S1.006 S7 360 Winter 200 +20% 100/60 Summer 62.004S5.000 SACO 60 Summer 200 +20% 100/60 Summer 100/60 Summer 62.692S5.001 S12 60 Summer 200 +20% 100/60 Summer 62.222S1.007 S11 360 Winter 200 +20% 100/60 Summer 62.004S1.008 S12 Attenuation 600 Winter 200 +20% 100/60 Summer 62.002S1.009 S13 Flow Control 360 Winter 200 +20% 100/60 Summer 200/360 Winter 62.000S1.010 S14 600 Winter 200 +20% 60.012




PNUS/MHName

SurchargedDepth(m)

FloodedVolume(m³)

Flow /Cap.

Overflow(l/s)

PipeFlow(l/s) Status

LevelExceeded

S1.000 S05 0.523 0.000 0.85 11.9 FLOOD RISKS1.001 S04A 0.810 0.000 1.35 18.7 FLOOD RISKS1.002 S04 0.897 0.000 0.61 8.2 SURCHARGEDS1.003 S03 1.009 0.000 0.62 8.2 SURCHARGEDS2.000 S01 1.200 0.302 1.23 17.1 FLOOD 1S2.001 S6 1.379 0.000 2.22 30.9 FLOOD RISKS1.004 S02 1.091 0.000 0.49 16.5 SURCHARGEDS1.005 S6 1.147 0.000 0.47 16.5 SURCHARGEDS3.000 S09 1.182 57.205 0.34 4.8 FLOOD 12S4.000 SACO 1.078 13.436 1.66 49.8 FLOOD 9S4.001 S10 1.114 0.000 0.34 12.0 FLOOD RISKS3.001 S08 1.361 0.000 0.79 27.4 FLOOD RISKS1.006 S7 1.372 0.000 0.92 49.6 SURCHARGEDS5.000 SACO 1.242 12.352 2.54 87.6 FLOOD 3S5.001 S12 0.846 0.000 2.31 87.0 SURCHARGEDS1.007 S11 1.500 0.000 0.94 75.6 SURCHARGEDS1.008 S12 Attenuation 1.525 0.000 0.58 50.1 SURCHARGEDS1.009 S13 Flow Control 1.847 0.012 0.40 5.0 FLOOD 3S1.010 S14 -0.088 0.000 0.36 5.0 OK

Documents

Site 7C, Edgar Mobbs Way, Northampton Flood Risk