ENVIRONMENT - WATERplanning.broxtowe.gov.uk/(S(xyjuqkzn3ejqsq3nk0esnemm))/Publish… · 3.2 A topographical survey of the wider site is included as Appendix E. 3.3 The model geometry

ENVIRONMENT - WATER PEVERIL SECURITIES & UK PROPERTY PARTNERSHIP (TOTON) LAND WEST OF TOTON LANE NOTTINGHAM

TECHNICAL NOTE 1: HYDROLOGY AND

HYDRAULIC MODELLING

March 2013

Ref: NTT/301/TN1

TOTON LANE

TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING MARCH 2013

NTT301/TN1

All comments and proposals contained in this report, including any conclusions, are based on information available to BWB Consulting during investigations.

The conclusions drawn by BWB Consulting could therefore differ if the information is found to be inaccurate or misleading. BWB Consulting accepts no liability

should this be the case, nor if additional information exists or becomes available with respect to this scheme.

a

Except as otherwise requested by the client, BWB Consulting is not obliged to and disclaims any obligation to update the report for events taking place after:-

a

(i) The date on which this assessment was undertaken, and

(ii) The date on which the final report is delivered

a

BWB Consulting makes no representation whatsoever concerning the legal significance of its findings or the legal matters referred to in the following report.

The information presented and conclusions drawn are based on statistical data and are for guidance purposes only. The study provides no guarantee against

flooding of the study site or elsewhere, nor of the absolute accuracy of water levels, flow rates and associated probabilities.

i

REVISION STATUS

REV

. N

O.

DESCRIPTION:

AU

TH

OR

CH

EC

KED

AP

PR

OV

ED

DATE

Draft First Internal Draft DJS DA DIH 29/01/13

A Revision A DJS DA DIH 29/01/13

B Model refined to include spills DJS DA DIH 31/03/13

TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING

MARCH 2013 NTT301/TN1

1

1.0 SUMMARY INFORMATION

Introduction

1.1 This Technical Note relates to the proposed development site at Toton Lane, Nottinghamshire. An application for outline planning permission has been made

and BWB Consulting have produced a Flood Risk Assessment (Ref: NTT/301/FRA Rev G) to support the planning application.

1.2 Further to the submission of the assessment the Environment Agency have issued

a letter of objection on two technical points as follows.

The ReFH methodology has been utilised to assess the likely flows for the watercourse. However, the ReFH method is known not to perform well on

urbanised catchments, and the URBEXT value for the catchment is 0.3163 (heavily urbanised). Further analysis is required prior to the flows being

agreed.

The client has used Manning's equation to assess the capacity of the watercourse. We suspect the gradient of the site will not be uniform, which

makes the use of Manning's equation inappropriate.

The objection letter is included as Appendix A.

1.3 The first point relates to the techniques used to calculate flow within the watercourse. Subsequent to the receipt of this objection further email

communication with the Environment Agency has taken place which provides further clarification on the nature of the ditchcourse catchment. Copies of the

email communication are included as Appendix B. The first part of this report will provide further clarification on the catchment of the ditchcourse and the

anticipated flows.

1.4 The basis of the Environment Agency’s second point is that the FRA has not fully considered the flood risk from the central drain/ditchcourse running through the

development, as it used Manning’s calculations completed individually for each section. The EA suggests that a hydraulic model should be produced which

demonstrates the capacity of the central drain more thoroughly.

1.5 The focus of the hydrological assessment is the small central ditch flowing through the the site as shown in Figure 1.1 overleaf.



2

Figure 1.1 – Location Plan

1.6 Based on the previous assessment, there was not considered to be a significant

risk of fluvial flooding posed directly to the development.

1.7 Manning’s assessments were made which were considered adequate given the size of the ditchcourse and scale and nature of the development. Nevertheless it

is agreed that a hydraulic model will provide a more accurate representation of

flows within the watercourse and at crossing points in particular.

Aims and Objectives

1.8 The aim of this report is to undertake a hydrological analysis of the catchment to quantify design return period flows. These flows will then be used to undertake a

hydraulic assessment of the drainage channel as it flows past the site.

Proposed Development

Existing Watercourse



1

2.0 HYDROLOGY ASSESSMENT

Catchment Description

2.1 As discussed in the communication with the EA included within Appendix B the catchment outline included with the previous assessment was erroneous and did

not fully reflect the study area. However the study area is less intensively developed than the parent catchment and covers a smaller area and the previous

assessment has overestimated the flows. An overlay of the FEH catchment and site area is included as Figure 1.2 below.

Figure 1.2 Catchment Overlay

2.2 In order to quantify fully the actual catchment of the site ditch a further analysis

of the wider topography has been carried out using freely available ordnance

survey level data. A drawing is included as Appendix C which shows a simple analysis of the catchment associated with the watercourse, the analysis has

adopted a worst case approach and it can reasonably be assumed that the catchment area calculated is larger than may actually be the case. Based upon

this analysis the maximum catchment area which could be attributed to the site ditch is 44 Hectares. In particular it can be seen by inspection that levels fall

away from rather than towards the right bank of the watercourse accordingly the northern area of the site is likely to drain to the lower reaches of the catchment

but is unlikely to connect along most of the reach.



2

2.3 It is proposed to utilise the Revitalised Flood Hydrograph methodology (ReFH).

The catchment descriptors for the neighbouring catchment have been extracted

from the FEH CD-Rom and the descriptors for site area and URBEXT have been adjusted to suit those of the proposed development. From inspection of the

proximity of the larger catchment it can be assumed with reasonable confidence that other catchment descriptors should closely match. Consideration was given

to the FEH STAT methodology but because of the small catchment size involved it was considered unlikely that a suitably homogenous pooling group could be

derived.

2.4 The 1:50,000 scale ordnance survey maps have been consulted in order to derive an appropriate value of URBAN50 based upon the mapping consulted a URBAN50

value of 0.07 is proposed and accordingly an URBEXT of 0.034 has been used in the ReFH analysis.

Return Periods

2.5 The flows for the catchment will be derived for the relevant design return periods. The most pertinent is considered to be the 100-year plus climate change event.

Whilst lower return period events may be of interest, the low flows involved are such that the creation of a stable hydraulic model is unlikely.

2.6 The 100-year return period defines the typical design event for Flood Zone 3a

(High Probability). To represent the potential impact of climate change on the 100-year return period, a manual 20% increase will be applied to the derived

flows.

ReFH Methodology

2.7 The ReFH model is based on the Flood Estimation handbook hydrological modelling techniques and is considered to be an improvement over the FSR/FEH

model which was previously used for rainfall-runoff estimation.

2.8 To support the ReFH method for wider user availability, software tools were developed to assist in the generation of design hydrographs, analysis of observed

events and reservoir routing studies. These tools include the ReFH Spreadsheet.

2.9 The ReFH Spreadsheet was used to define the peak flows for the identified catchment for the 1:100 year return period based on the catchment descriptors

extracted from the FEH CD-ROM adjusted as described in section 2.6.

2.10 The catchment descriptors were input to the spreadsheet and flows were generated by defining hydrograph parameters for the return periods of interest

and selecting the recommended rainfall profile.

2.11 In accordance with the guidance for the method a 2.2 hour event was identified as being critical and a time step of 0.2 hours was used to derive the flows.

2.12 The estimated peak flow rate generated for the study catchment area was

0.29m3/s ReFH Spreadsheet outputs are also included for reference as Appendix D. Applying a manual 20% increase to approximate the potential impacts of

climate change (CC) results in a peak flow rate of 0.348m3/s for the 100-year CC

event.



1

3.0 HYDRAULIC MODELLING

Modelling Software

3.1 The hydraulic modelling software used for the study was Halcrow’s ISIS version 3.6. A full un-steady flow model was used to represent flood flows through the

ditchcourse, as derived from the hydrological analysis above.

3.2 A topographical survey of the wider site is included as Appendix E.

3.3 The model geometry is defined by a number of cross sections. The hydraulic

model has been created using data from a very detailed topographical survey

which includes a 1m grid of levels adjacent to each ditch crossing the detailed topographic survey is included as Appendix E1. In order to quantify the flow

regime at each ditch crossing a selection of reservoir nodes and flood plain units were created for each element of the model where flow across the banks was

predicted by preliminary model runs.

3.4 The GIS Visualizer has also been used to provide an overview of the model schematic and a printout of the node locations has been included as Appendix F.

Roughness Coefficients

3.5 The ditchcourse roughness coefficients used in the hydraulic model are Manning’s

“n” values. Values were estimated from site observation and reference to guidelines within published documentation.

3.6 Manning’s n was set to 0.04 for all parts of channel and floodplain. This is

considered representative of a fairly rough channel which will provide a worst case approximation of the actual ditchcourse conditions.

3.7 Notwithstanding the appropriateness of the selected Manning’s value sensitivity

testing for manning’s has been carried out.

Boundary Conditions

3.8 The upstream boundary was set using the peak flow estimate derived from the

hydrological assessment based upon the ReFH analysis.

3.9 At the downstream boundary no flood levels or hydraulic boundary conditions are

available. In order to model the worst case flow a normal flow depth boundary

has been applied simulating a very shallow downstream gradient of 1:500.



2

Model Results

3.10 The peak water levels for the 100-year+20% return periods through the site have

been extracted from the model and are summarised in the Table 3.1 below for a model with a Mannings coefficient of 0.04, 0.06 and 0.03.

Ditchcourse

Section

Q100CC Peak

Level

(m AOD)

Manning’s 0.04

Q100CC Peak

Level

(m AOD)

Manning’s 0.06

Q100CC Peak

Level

(m AOD)

Manning’s 0.02

TL01 60.53 60.61 60.46

TL02 59.99 60.02 59.92

TL03 59.23 59.27 59.11

TL04 58.19 58.24 58.10

TL05 56.90 56.99 56.81

TL06 55.85 55.90 55.75

TL07 55.23 55.29 55.13

TL07A 54.96 54.96 54.96

TL08 54.25 54.27 54.18

TL09 53.68 53.71 53.61

TL10 53.30 53.30 53.29

TL11 53.04 53.09 52.96

TL12 52.56 52.63 52.52

TL12A 52.41 52.40 52.42

TL13 51.78 51.84 51.70

TL14 51.21 51.29 51.11

TL15 51.00 51.06 50.88

TL16 50.76 50.84 50.67

TL17 50.53 50.61 50.39

TL18 50.32 50.41 50.20

TL19 50.13 50.21 49.99

TL20 49.53 49.59 49.45

TL21 48.72 48.80 48.63

TL22 48.23 48.32 48.15

TL23 47.81 47.87 47.70

TL24 47.24 47.31 47.16

TL25 46.44 46.50 46.38

TL26 45.84 45.92 45.71

TL27 44.85 44.90 44.75

TL28 43.85 43.94 43.74



3

TL29 41.94 42.00 41.88

TL29A 40.72 40.71 40.72

TL30 40.10 40.20 40.01

TL31 39.93 40.05 39.77

Table 3.1 – Modelled Flood Levels

3.11 A long section plot of the full modelled reach has also been included as Appendix

G. It is notable that changes in manning’s introduce increased levels along most

of the reach, however at the critical ditch crossings the importance of the manning’s coefficient is greatly reduces and the dominant hydraulic control is

considered to be the downstream pipe diameter.

3.12 Based on the analysis of the long section, maximum stage output and topographical survey it is apparent that the ditchcourse does not spill over bank

along most of the reach. However some overtopping within the site can be noted where two of the piped ditch crossings are located. A time series output of the

flow across the two spills has been included as Figure 3.1 below.

Figure 3.1 - Flow across spills located at field drain crossings.

3.13 The maximum level at the two spills is 54.96m AOD and 52.41m. In both location ns flow is above the upstream ditch top. In order to provide some understanding

as to the flow patterns involved a system of floodplain units and spills was included in the model. A schematic of the spill network is included overleaf as

Figure 3.2 with flow directions indicated by arrows.

3.14 It is clear from the analysis that overland flow between nodes will occur but that flow will return to the watercourse a short distance downstream from the initial

spill.

Time Series: TL07Su - Flow : TL07Su; 0 - 8.000 h.

Time (h)

87.576.565.554.543.532.521.510.50

Flo

w (

m3/s

)

0.24

0.23

0.22

0.21

0.2

0.19

0.18

0.17

0.16

0.15

0.14

0.13

0.12

0.11

0.1

0.09

0.08

0.07

0.06

0.05

0.04

0.03

0.02

0.01

0

Time Series: TL12Su - Flow : TL12Su; 0 - 8.000 h.

Time (h)

87.576.565.554.543.532.521.510.50

Flo

w (

m3/s

)

0.017

0.016

0.015

0.014

0.013

0.012

0.011

0.01

0.009

0.008

0.007

0.006

0.005

0.004

0.003

0.002

0.001

0

-0.001

-0.002

-0.003



4

Figure 3.2 - Flow routing across spills at ditch crossings

3.15 The spill at nodes TL09RSu and TL12RSu are all negative as shown in Figure 3.3

below. Flow at TL09Rsu is -0.19l/s and at TL12Rsu up to -0.12l/s.

Figure 3.3 – Potential Flow rates and Directions

Potential Impact on Development and Recommended Floor Levels

3.16 With reference to the proposed development, no particular specification for a minimum finished floor level has been set, however the proposed development

Time Series: TL09RSpU - Flow : TL09RSpU; 0 - 8.000 h.

Time (h)

87.576.565.554.543.532.521.510.50

Flo

w (

m3/s

)

0

-0.005

-0.01

-0.015

-0.02

-0.025

-0.03

-0.035

-0.04

-0.045

-0.05

-0.055

-0.06

-0.065

-0.07

-0.075

-0.08

-0.085

-0.09

-0.095

-0.1

-0.105

-0.11

-0.115

-0.12

-0.125

-0.13

-0.135

-0.14

-0.145

-0.15

-0.155

-0.16

-0.165

-0.17

-0.175

-0.18

-0.185

-0.19

-0.195

Time Series: TL12RSpU - Flow : TL12RSpU; 0 - 8.000 h.

Time (h)

87.576.565.554.543.532.521.510.50

Flo

w (

m3/s

)

0

-0.01

-0.02

-0.03

-0.04

-0.05

-0.06

-0.07

-0.08

-0.09

-0.1

-0.11

-0.12

TL7A

TL12A

TL07Su

TL09RSu

TL12RSu

TL12Su



5

layout is such that properties are to be set reasonably far back from the

ditchcourse.

3.17 Overland flow is predicted within the current model adjacent to the ditchcourse on the right bank, however flow is predicted to re-enter the watercourse a short

distance downstream from the spill.

3.18 The proposed development will respect the layout of the existing watercourse, however it is recommended that the watercourse is improved along its length and

that any crossings are designed to accommodate at least the 1:100+cc flow plus

An appropriate freeboard. Accordingly a development can clearly be brought forward which will be safe and will not increase flood risk elsewhere.



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4.0 DRAINAGE STRATEGY

4.1 The proposed development covers a total area of approximately 41.3 Hectares, however it is clear that a substantial portion of the development will not be

altered by the proposals. It is considered that approximately 28 Hectares of the development are to be actively developed and this gross area will be used in

these calculations. A printout of an IH124 Calculation is included as Appendix H the results are summarised below in Table 4.1.

Return Period Runoff Rate

1 Year 87.9

QBAR 105.9

30 Year 207.5

100 Year 272.2

Table 4.1 – IH124 Runoff Rates

4.2 The proposed development is split between a distinct north and south

development which are separated by the ditchcourse. The discharge rate should be split between north and south development areas as suggested in Table 4.2

below.

Return Period North Site South Site Total Runoff

1 Year 52.7 35.2 87.9

QBAR 63.5 42.4 105.9

30 Year 124.5 83.0 207.5

100 Year 163.3 108.9 272.2

Table 4.2 – Apportioned Discharge Rates

4.3 It has been recommended that discharge from the proposed development does

not exceed the discharge rate of the existing site at each return period, resulting in a variable discharge rate.

4.4 An outline design has been carried out using Microdrainage Windes source control

to confirm the volume storage features which would be required to attenuate flows from the development to these rates. The design has been carried out

assuming a fixed discharge device calibrated intended to restrict flows to the 1:100 year rate at 1m of head. The actual discharge rates at each return period

are a function of the anticipated depth in the pond and differ from the intended discharge rate. In all cases however the actual discharge rate is less than the

maximum rate as set out in Table 4.2.



7

4.5 A full set of printouts from the calculation are included as Appendix I and a

summary of the required volumes, depths and discharge rates associated with an

attenuation pond is provided below in Table 4.3 for a range of return periods up to the 1:100 year event plus an allowance of 30% for climate change.

Return Period

North Pond

South Pond

Depth(mm) Volume(m3) Discharge Rate(l/s)

Depth(mm) Volume(m3) Discharge Rate(l/s)

1 Year 268 1000.8 47.3 227 684.0 30.0

QBAR 305 1153.8 58.7 259 788.9 37.0

30 Year

551 2187.0 111.8 491 1589.8 54.2

100 Year

CC

946 4074.0 157.1 797 2789.3 95.0

Table 4.3 – Site Wide Attenuation Volumes and actual discharge rates

4.6 The proposed masterplan has specifically set aside space in the south west corner

to accommodate anticipated attenuation basins at a depth of not more than 1.5m deep. In addition to the attenuation basins permeable paving will be used within

the development wherever possible and two stages of treatment will be used with

the attenuation basin being the second stage of the train.

4.7 In addition to the staged discharge volumes outlined above it is also necessary to

accommodate the long term storage volume. This is defined as the difference in

runoff volume pre- and post-development for the 100 year 6 hour event, (the additional runoff generated) should be disposed of by way of infiltration, or if this

is not feasible due to soil type, discharged from the site at flow rates below 2 l/s/ha.

4.8 Microdrainage Windes was used to generate a greenfield Runoff Volume and a

printout of the results is included as Appendix J. A total volume of 7,141m3 is predicted.

4.9 Hydrograph tables were extracted from Microdrainage Windes and a summation

of total output rates shows a total output volume for the 1:100 year 6 hour event of 5,709m3 at the northern pond and 3796m3 at the southern pond. A total

volume of 9,505m3 is therefore predicted and the difference in volume pre and post development is 2,364m3. Apportioning this volume across the two ponds

would suggest that an additional 1,522m3 of volume would be required in the northern pond and an additional 1,012m3 in the southern pond.

4.10 The substantial provision of open space in the south western area of the site is

more than large enough to accommodate the volumes required. A total area of 40,000m2 is provided. Considering that the Windes calculations have been

prepared without accounting for upstream storage volume available in the piped

system the calculations can be considered to be conservative and during detailed design a lower volume may actually be required.



8

4.11 The application is for outline approval and there will be ample opportunity during

the detailed design stage to develop the proposed strategy forward and maximise

the potential for further amenity and biodiversity improvements. In any event it is clear that there is sufficient space set aside for a viable and technically feasible

design to be incorporated into the proposed development.



9

5.0 CONCLUSIONS AND RECOMMENDATIONS

5.1 The hydrological analysis derived flows for the catchment of the site ditchcourse using the Flood Estimation Handbook ReFH methodology for the maximum

1:100+20% design return period. Catchment descriptors were adjusted based upon an independent assessment of the actual catchment size and criteria. This

methodology is considered to be representative of the catchment as it is based on the latest hydrological techniques and software.

5.2 The flow rates derived as part of this assessment were utilised within a hydraulic

assessment of the ditchcourse reach through the study site.

5.3 Based on the hydraulic modelling undertaken, there is not considered to be a significant risk posed to the site from the ditchcourse up to the 100-year plus

climate change return period.

5.4 Some out of bank flow associated with the pipe crossings within the model is anticipated, however the total area of the floodflow is not extensive and no

impact to the development is anticipated. The model indicates that flow would progress from the spill points overland and re-enter the watercourse a short

distance downstream.

5.5 A sensitivity analysis of manning’s n roughness values demonstrates that the model is stable and there are no significant impacts on flood levels as a result of

changing model parameters.

5.6 A detailed analysis of drainage requirements has demonstrated that there is adequate capacity at the site to attenuate the runoff to predevelopment levels

and introduce an appropriate drainage system, at least a two stage treatment train would be anticipated.

APPENDIX A

Environment Agency Objection

Environment Agency

Trentside Offices Scarrington Road, West Bridgford, Nottingham, NG2 5FA. Customer services line: 03708 506 506 www.environment-agency.gov.uk

Cont/d..

Mr R Dawson Broxtowe Borough Council Development Control Town Hall Foster Avenue Beeston Nottingham NG9 1AB

Our ref: LT/2012/115280/01-L01 Your ref: 12/00585/OUT Date: 05 November 2012

Dear Mr Dawson OUTLINE APPLICATION WITH POINTS OF ACCESS TO BE DETERMINED FOR A MIXED USE DEVELOPMENT INCORPORATING A MAXIMUM OF 775 N° DWELLINGS, 380 SQM CONVENIENCE STORE, 2 N° 95 SQM RETAIL UNITS, 2800 SQM B1(A) AND (B) UNITS, PUBLIC HOUSE/RESTAURANT AND 80 BEDROOM HOTEL (MAXIMUM 3450 SQM), EDUCATION PROVISION (MAXIMUM 2300 SQM), DAY NURSERY ( MAXIMUM 450 SQM), SITE FOR MEDICAL SURGERY (0.03 HA), SITE FOR COMMUNITY USE (0.05 HA), OPEN SPACE, CHANGE OF USE OF AGRICULTURAL LAND TO DOMESTIC CURTILAGES, HIGHWAYS, DRAINAGE AND ASSOCIATED INFRASTRUCTURE, REMOVAL OF PYLONS AND OVERHEAD ELECTRICITY CABLES, ERECTION OF TERMINAL PYLON AND DEMOLITION OF BESSELL LANE FARM AND OUTBUILDINGS AND 361 TOTON LANE – LAND TO THE WEST OF TOTON LANE STAPLEFORD NOTTINGHAMSHIRE Thank you for referring the above application which was received on 15 October 2012. Environment Agency Position In the absence of an acceptable Flood Risk Assessment (FRA) we object to the grant of planning permission and recommend refusal on this basis for the following reason: Reason The FRA submitted with this application does not comply with the requirements set out in paragraph 9 of the Technical Guide to the National Planning Policy Framework. The submitted FRA does not therefore, provide a suitable basis for assessment to be made of the flood risks arising from the proposed development. In particular, the submitted FRA fails to sufficiently asses the flood risk from the watercourse that crosses the site in the following respect:

End

2

The ReFH methodology has been utilised to assess the likely flows for the watercourse. However, the ReFH method is known not to perform well on urbanised catchments, and the URBEXT value for the catchment is 0.3163 (heavily urbanised). Further analysis is required prior to the flows being agreed. The client has used Manning's equation to assess the capacity of the watercourse. We suspect the gradient of the site will not be uniform, which makes the use of Manning's equation inappropriate. Overcoming our objection You can overcome our objection by submitting a FRA which covers the deficiencies highlighted above and demonstrates that the development will not increase risk elsewhere and where possible reduces flood risk overall. Please note it is considered likely that our objection will be removed in terms of being able to develop the site. However, as the watercourse may impact upon master planning for the site, it is felt prudent to object to the FRA at this stage, as opposed to recommending a condition inclusive of further work analysis on the watercourse. We ask to be re-consulted with the results of the FRA. We will provide you with bespoke comments within 21 days of receiving formal re-consultation. Our objection will be maintained until an adequate FRA has been submitted. Additional Comments Subject to the removal of the above objection, conditions will be recommended regarding water resources, water quality and biodiversity. Yours sincerely Mr Robert Gilmore Planning Liaison Officer Direct dial 0115 8463699 Direct e-mail [email protected] cc Signet Planning Ltd

mailto:[email protected]

Environment Agency

Trentside Offices Scarrington Road, West Bridgford, Nottingham, NG2 5FA. Customer services line: 03708 506 506 www.environment-agency.gov.uk

Cont/d..

Mr Paul Stone Signet Planning Ltd Strelley Hall Main Street Strelley NOTTINGHAM NG8 6PE

Our ref: LT/2012/115280/01-L01 Your ref: Date: 06 November 2012

Dear Mr Stone OUTLINE APPLICATION WITH POINTS OF ACCESS TO BE DETERMINED FOR A MIXED USE DEVELOPMENT INCORPORATING A MAXIMUM OF 775 N° DWELLINGS, 380 SQM CONVENIENCE STORE, 2 N° 95 SQM RETAIL UNITS, 2800 SQM B1(A) AND (B) UNITS, PUBLIC HOUSE/RESTAURANT AND 80 BEDROOM HOTEL (MAXIMUM 3450 SQM), EDUCATION PROVISION (MAXIMUM 2300 SQM), DAY NURSERY ( MAXIMUM 450 SQM), SITE FOR MEDICAL SURGERY (0.03 HA), SITE FOR COMMUNITY USE (0.05 HA), OPEN SPACE, CHANGE OF USE OF AGRICULTURAL LAND TO DOMESTIC CURTILAGES, HIGHWAYS, DRAINAGE AND ASSOCIATED INFRASTRUCTURE, REMOVAL OF PYLONS AND OVERHEAD ELECTRICITY CABLES, ERECTION OF TERMINAL PYLON AND DEMOLITION OF BESSELL LANE FARM AND OUTBUILDINGS AND 361 TOTON LANE LAND TO THE WEST OF TOTON LANE STAPLEFORD NOTTINGHAMSHIRE The Environment Agency has recently been consulted by the Local Authority regarding the above development proposal. Please find enclosed a copy of our comments for your information. This response represents our advice as a statutory consultee on environmental issues associated with the proposed development. The reply should not be confused with the Council's decision notice, which will be issued by the Local Authority following determination of the application. Please contact the Local Authority if you wish to discuss the final decision to be made on this application. If you have any queries about the Agency's response, please don't hesitate to contact me. Yours sincerely

End

2

Mr Robert Gilmore Planning Liaison Officer Direct dial 0115 8463699 Direct fax Direct e-mail [email protected]

APPENDIX B

EA communication

1

Josephine Green

Subject: FW: Toton Lane - LT/2012/115280/01-L01

Darren, Thank you for your e-mail. May I respectfully request that when consulting us regarding a current planning application you go via our planning liaison colleagues. As well as facilitating our records management, this will ensure that we are able to respond to our many clients in a fair and equitable manner. I have on this occasion responded to your e-mail directly and copied in the relevant colleague. The points you have made in your e-mail have been considered. Unfortunately we are not yet in a position to agree that the flood risk assessment for the site is sufficient to enable us to remove our objection. I will outline our reasons for this below. I will say, over the long term it is unlikely that the EA will object to this application in terms of flood risk. However, we are not currently satisfied that the flood risk from the brook / drain has been considered adequately and this could have impacts on the master plan layout. For that reason we feel it prudent to maintain our objection until the issues have been resolved. You have identified the fact that the data extracted from the FEH CD is erroneous for the drain's catchment. This is an excellent illustration of why our flood estimation guidelines recommend that checks are made on the data extracted from the FEH CD ROM as a matter of course. The FEH CD Rom contains errors as you have illustrated with your further investigation. An accurate FRA would now illustrate the true catchment for the drain and amend the catchment descriptors used in the REFH. We will then have a more accurate estimation of the flows for the drain. Please note in order to recalculate the URBEXT value, you will most likely have to use a an estimation of URBAN from 1:50,000 OS mapping and convert this value using the formula URBAN=URBEXT*2.05. You have then maintained that you have calculated the channel capacity at four locations. Whilst this may be true, I have at this stage no demonstration that the channel is uniform and steady. You are aware that Manning's calculations are only relevant to steady, uniform channels. As we cannot say with confidence that the channel is producing steady / uniform flow, four estimation points for this drain is insufficient in demonstrating that the channel has sufficient capacity throughout its length. There may well be other locations where the channel is more constricted and flows may overtop the channel for all we know via the information presented. Further to this, you will also be aware that Manning's estimations are not appropriate where structures are present. Using simple aerial photography it would seem there are two or three structures in the channel. These have not been discussed in the FRA and require assessment. You have stated that in your view complicated hydraulic modelling seems entirely unnecessary. I am inclined to agree that a complicated model is unnecessary. However, I would also maintain that a simple steady-state backwater model may be the most appropriate way of demonstrating the risk from this watercourse. I am presuming the channel has been surveyed (to support your conclusions for the Mannings calculations) and thus the use of a 1 dimensional model will be a relatively simple way forward. I will leave this for your consideration. Based on the above I would suggest the FRA requires revision. Further to this there is another issue which we would require you to consider (I do apologise if this was not raised in our first response). You have based the suggested permissible discharge rate on the current greenfield rate for the whole site of 44.9 ha. You have then estimated the post developed discharge based upon only half of the site contributing to drainage (22ha). Whilst it is occasionally acceptable to exclude some garden / soft landscaping areas from site drainage I would say that only considering 50% of the site is unreasonable. This is especially so given that this is a steep site and open area are likely to continue to contribute to greenfield run-off rates. Kind regards David Turnbull Flood Risk Management Technical Advisor Partnership and Strategic Overview Team - Notts and Tidal Trent 0115 846 2681 [email protected] Environment Agency, Trentside Offices, Scarrington Road, West Bridgford, Nottingham NG2 5BR

josephine.green

Rectangle

2

From: Darren Stewart [mailto:[email protected]] Sent: 19 November 2012 09:13 To: Turnbull, David Cc: James Smith; Anabel Christmas; Adrian Goose; Antony Calvert; Stuart Dunhill; [email protected] Subject: Toton Lane - LT/2012/115280/01-L01

Click here to report this email as spam.

David, I am in receipt of your consultation response regarding the above application 12/00858/OUT at Toton Lane Nottingham. With regard to the watercourse running through the site we have re‐assessed the flows and FEH catchment descriptors and concur that the URBEXT value is higher than would be recommended for an ReFH method. However, on re‐examining the FEH catchment it is clear that the watercourse selected within FEH is not fully representative of the watercourse present on site. It appears that the watercourse on site is only a small part of the larger catchment on which the flows were calculated. I have overlaid the REFH maps on to appropriate OS background below and I trust you can see that the extracted catchment is an overestimate of the actual catchment which will drain to the watercourse. In reality peak flows to the watercourse are likely to be a fraction of those predicted by the ReFH method . The ReFH method indicates peak flows of 1.2m3/s and I have included the output from the calculation.

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the

APPENDIX C

Catchment Analysis

APPENDIX D

ReFH Output

Revitalised FSR/FEH rainfall runoff methodSpreadsheet application report

User name Darren Stewart Catchment name Toton Lane - Entire Catchment Date/time modelled 30-Jan-2013 17:49

Company name BWB Consulting Catchment easting 448300 Version 1.4

Project name Toton Lane Catchment northing 335900

Catchment area 0.44

Summary of model setup

Design rainfall parameters Loss model parameters Routing model parameters Baseflow model parameters

Return period (yr) 100 Cmax (mm) 486 Tp (hr) 1.61 BL (hr) 31.5

Duration (hr) 2.2 Cini (mm) 106 Up 0.65 BR 1.53

Timestep (hr) 0.2 a factor 0.83 Uk 0.8 BF0 (m3/s) 0

Season Winter

Summary of results

FEH DDF rainfall (mm) 51.6 Peak rainfall (mm) 6.9

Design rainfall (mm) 30.6 Peak flow (m3/s) 0.3

Results GraphSeries Design Rainfall Net rainfall Direct runoff Baseflow Total flow

Unit mm mm m3/s m

3/s m

3/s

0.0 0.7 0.1 0.0 0.0 0.0

0.2 1.1 0.2 0.0 0.0 0.0

0.4 1.9 0.4 0.0 0.0 0.0

0.6 3.1 0.6 0.0 0.0 0.0

0.8 5.0 1.0 0.0 0.0 0.0

1.0 6.9 1.5 0.0 0.0 0.0

1.2 5.0 1.1 0.0 0.0 0.1

1.4 3.1 0.7 0.1 0.0 0.1

1.6 1.9 0.4 0.1 0.0 0.1

1.8 1.1 0.3 0.1 0.0 0.1

2.0 0.7 0.2 0.2 0.0 0.2

2.2 0.0 0.0 0.2 0.0 0.2

2.4 0.0 0.0 0.2 0.0 0.3

2.6 0.0 0.0 0.3 0.0 0.3

2.8 0.0 0.0 0.3 0.0 0.3

3.0 0.0 0.0 0.3 0.0 0.3

3.2 0.0 0.0 0.3 0.0 0.3

3.4 0.0 0.0 0.2 0.0 0.3

3.6 0.0 0.0 0.2 0.0 0.3

3.8 0.0 0.0 0.2 0.0 0.2

4.0 0.0 0.0 0.2 0.0 0.2

4.2 0.0 0.0 0.2 0.0 0.2

4.4 0.0 0.0 0.1 0.0 0.2

4.6 0.0 0.0 0.1 0.0 0.2

4.8 0.0 0.0 0.1 0.0 0.2

5.0 0.0 0.0 0.1 0.0 0.1

5.2 0.0 0.0 0.1 0.0 0.1

5.4 0.0 0.0 0.1 0.0 0.1

5.6 0.0 0.0 0.1 0.0 0.1

5.8 0.0 0.0 0.1 0.0 0.1

6.0 0.0 0.0 0.0 0.0 0.1

6.2 0.0 0.0 0.0 0.0 0.1

6.4 0.0 0.0 0.0 0.0 0.1

6.6 0.0 0.0 0.0 0.0 0.1

6.8 0.0 0.0 0.0 0.0 0.1

7.0 0.0 0.0 0.0 0.0 0.1

7.2 0.0 0.0 0.0 0.0 0.0

7.4 0.0 0.0 0.0 0.0 0.0

7.6 0.0 0.0 0.0 0.0 0.0

7.8 0.0 0.0 0.0 0.0 0.0

Total (mm) 30.6 6.5 6.5 2.0 8.5

Audit comments

Model run with ReFH dll version 1.4.0005

Catchment

Catchment descriptors imported from file

Catchment descriptor file = 'Smaller Toton Lane.csv'

Catchment decriptor file exported from CD ROM version 3

Catchment descriptor file exported on 30-Jan-2013 10:35

BFIHOST value of 0.618 used

PROPWET value of 0.35 used

SAAR value of 639 used

DPLBAR value of 0.96 used

DPSBAR value of 31.8 used

URBEXT value of 0.037 used

URBEXT changed from imported value of 0.3163 to 0.037

Catchment area changed from imported value of 1.03 to 0.44

C value of -0.02696 used

D1 value of 0.33133 used



E value of 0.30474 used

F value of 2.3783 used

Rainfall

Recommended season is Winter, as URBEXT < 0.125

ReFH design standard Seasonal Correction Factor of 0.61 applied

ReFH design standard Areal Reduction Factor of 0.98 applied

Loss Model

CMax derived from catchment descriptors

ReFH design standard Cini used

ReFH design standard a factor used

Routing Model

Tp derived from catchment descriptors

ReFH design standard used for Up

ReFH design standard used for Uk

Baseflow Model

BL derived from catchment descriptors

BR derived from catchment descriptors

ReFH design standard BF0 used

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0

1

2

3

4

5

6

7

8

Flo

w (

m3

/s)

Ra

infa

ll (

mm

)

Time (hr)

ReFH Model Output: Toton Lane - Entire Catchment

Rainfall Net rainfall Total flow Direct runoff Baseflow

Page 1 of 1

APPENDIX E

Topographical Survey

APPENDIX E

Ditchcourse Survey

44

87

50

E4

48

75

0E

44

88

00

E4

48

80

0E

44

88

50

E4

48

85

0E

44

89

00

E4

48

90

0E

44

89

50

E4

48

95

0E

44

90

00

E4

49

00

0E

44

90

50

E4

49

05

0E

44

91

00

E4

49

10

0E

44

91

50

E4

49

15

0E

44

92

00

E4

49

20

0E

44

92

50

E4

49

25

0E

44

93

00

E4

49

30

0E

44

93

50

E4

49

35

0E

44

94

00

E4

49

40

0E

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.

KEY

c Copyright BWB Consulting Ltd

Drawing No. Revision

Drawing Status

Size

Drawing Title

Project Title

Scale

Reviewed

Drawn

A1

ISSUES & REVISIONS

Rev Date Details of issue / revision RevDrw

Client

Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100

www.bwbconsulting.com

Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


P1NTT/301/1300

PRELIMINARY

J. Green

D.Stewart

1:1,000

TOTON LANE SURVEY

TOTON LANE

PEVERIL SECURITIES LTD

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.



OTHERWISE.

4. ANY DISCREPANCIES NOTED ON SITE ARE TO BE

REPORTED TO THE ENGINEER IMMEDIATELY.

KEY



Drawing Status

Size

Drawing Title

Project Title

Scale

Reviewed

Drawn

A3

ISSUES & REVISIONS


Client

Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


P1NTT/301/1302

PRELIMINARY

J. Green

D. Stewart

1:500

TOTON LANE SURVEY -

DITCH CROSSING 2

TOTON LANE


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.



OTHERWISE.

4. ANY DISCREPANCIES NOTED ON SITE ARE TO BE

REPORTED TO THE ENGINEER IMMEDIATELY.

KEY



Drawing Status

Size

Drawing Title

Project Title

Scale

Reviewed

Drawn

A3

ISSUES & REVISIONS


Client

Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


Birmingham | 0121 233 3322

Leeds | 0113 233 8000

London | 020 7234 9122

Manchester | 0161 233 4260

Nottingham | 0115 924 1100


P1NTT/301/1301

PRELIMINARY

J. Green

D. Stewart

1:500

TOTON LANE SURVEY -

DITCH CROSSING 1

TOTON LANE


APPENDIX F

Ditchcourse Model Schematic

APPENDIX G

Long Section Plot

0 25

50

75

10

0

12

5

15

0

16

7

19

2

21

7

24

2

26

7

28

1

30

6

33

1

35

6

38

1

40

6

43

1

45

6

48

1

50

6

53

1

55

6

58

1

60

6

63

1

65

6

68

1

69

8

71

8

Chainage,

60

.46

59

.92

59

.11

58

.10

56

.81

55

.75

55

.13

54

.96

53

.61

53

.29

52

.96

52

.52

52

.42

51

.11

50

.88

50

.67

50

.39

50

.20

49

.99

49

.44

48

.63

48

.15

47

.70

47

.16

46

.38

45

.71

44

.75

43

.74

41

.88

40

.72

39

.77

Q100+CC MANNINGS 0.02

60

.61

60

.02

59

.27

58

.24

56

.99

55

.90

55

.29

54

.96

53

.71

53

.30

53

.09

52

.63

52

.40

51

.29

51

.06

50

.84

50

.61

50

.40

50

.21

49

.59

48

.80

48

.32

47

.87

47

.31

46

.50

45

.92

44

.90

43

.94

41

.99

40

.71

40

.04


60

.53

59

.99

59

.23

58

.19

56

.90

55

.85

55

.23

54

.96

53

.67

53

.30

53

.04

52

.56

52

.41

51

.21

51

.00

50

.76

50

.53

50

.32

50

.13

49

.53

48

.72

48

.23

47

.81

47

.24

46

.44

45

.84

44

.85

43

.85

41

.94

40

.72

39

.92


60

.25

59

.60

58

.81

57

.88

56

.58

55

.51

54

.83

54

.55

53

.43

53

.09

52

.67

52

.18

51

.65

50

.83

50

.42

50

.40

50

.08

49

.97

49

.64

49

.25

48

.40

47

.89

47

.46

46

.94

46

.18

45

.46

44

.61

43

.49

41

.76

40

.24

39

.41

BED ELEVATION

60

.69

60

.07

59

.28

58

.38

57

.21

56

.13

55

.58

55

.30

54

.12

53

.78

53

.48

53

.00

52

.47

51

.85

51

.76

51

.60

51

.20

50

.88

50

.57

49

.98

49

.20

48

.74

48

.24

47

.71

46

.96

46

.37

45

.56

44

.43

42

.69

41

.17

40

.25

Left bank,

60

.54

60

.14

59

.23

58

.32

57

.30

56

.07

55

.33

55

.06

53

.92

53

.42

53

.28

52

.82

52

.29

51

.60

51

.53

51

.37

51

.28

50

.96

50

.75

50

.11

49

.52

48

.90

48

.24

47

.73

46

.95

46

.32

45

.45

44

.25

42

.79

41

.27

40

.21

Right bank,

TL

01

TL

02

TL

03

TL

04

TL

05

TL

06

TL

07

TL0

7A

TL

09

TL

10

TL

11

TL

12

TL1

2A

TL

14

TL

15

TL

16

TL

17

TL

18

TL

19

TL

20

TL

21

TL

22

TL

23

TL

24

TL

25

TL

26

TL

27

TL

28

TL

29

TL2

9A

TL

31

Label,

Q100+CC MANNINGS 0.02Q100+CC MANNINGS 0.06Q100+CC MANNINGS 0.04BED ELEVATIONLeft bank,Right bank,

Long Section: TL01 - TL31 - Bed Profile; 0 - 8 h. Node,: TL01

Horizontal scale, 1:3355Vertical Scale, 1:227 Data file, Created on, 02/04/2013 11:11:27

39.00

100 200 300 400 500 600 700Node Label

40.0

04

5.0

05

0.0

05

5.0

06

0.0

0

Ele

vatio

n (m

AD

)

APPENDIX H

IH124 Runof Rates

BWB Partnership Page 1

Friars Studio

3 Friar Gate

Derby DE1 1BU

Date 12/03/2013 13:32 Designed by darren.st...

File South Pond(1in2)... Checked by

Micro Drainage Source Control W.12.6.1

ICP SUDS Mean Annual Flood

©1982-2011 Micro Drainage Ltd

Input

Return Period (years) 100 Soil 0.450Area (ha) 28.000 Urban 0.000SAAR (mm) 616 Region Number Region 4

Results l/s

QBAR Rural 105.9QBAR Urban 105.9

Q100 years 272.2

Q1 year 87.9Q30 years 207.5Q100 years 272.2

APPENDIX I

Source Control Printouts


Friars Studio

3 Friar Gate

Derby DE1 1BU


File South Pond(1in10... Checked by


Summary of Results for 100 year Return Period (+30%)


Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status

15 min Summer 98.521 0.521 73.2 1700.2 O K30 min Summer 98.585 0.585 78.8 1939.5 O K60 min Summer 98.647 0.647 83.9 2180.2 O K120 min Summer 98.697 0.697 87.8 2379.8 O K180 min Summer 98.713 0.713 89.0 2444.4 O K240 min Summer 98.717 0.717 89.3 2460.7 O K360 min Summer 98.720 0.720 89.5 2470.9 O K480 min Summer 98.717 0.717 89.2 2459.0 O K600 min Summer 98.710 0.710 88.7 2431.3 O K720 min Summer 98.701 0.701 88.0 2394.0 O K960 min Summer 98.688 0.688 87.1 2343.2 O K1440 min Summer 98.651 0.651 84.2 2197.8 O K2160 min Summer 98.592 0.592 79.4 1968.7 O K2880 min Summer 98.539 0.539 74.9 1768.8 O K4320 min Summer 98.433 0.433 64.8 1381.8 O K5760 min Summer 98.366 0.366 57.4 1145.1 O K7200 min Summer 98.324 0.324 51.2 1003.0 O K8640 min Summer 98.296 0.296 45.1 910.5 O K10080 min Summer 98.274 0.274 40.3 838.2 O K

15 min Winter 98.576 0.576 78.1 1907.0 O K30 min Winter 98.646 0.646 83.8 2178.2 O K60 min Winter 98.715 0.715 89.1 2453.0 O K120 min Winter 98.773 0.773 93.3 2687.7 O K

Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)

15 min Summer 168.291 2930 min Summer 97.451 4360 min Summer 56.431 70120 min Summer 32.677 126180 min Summer 23.738 180240 min Summer 18.922 212360 min Summer 13.746 274480 min Summer 10.957 340600 min Summer 9.190 408720 min Summer 7.960 476960 min Summer 6.442 6141440 min Summer 4.782 8802160 min Summer 3.549 12642880 min Summer 2.873 16444320 min Summer 2.025 23525760 min Summer 1.580 30647200 min Summer 1.304 37528640 min Summer 1.114 449610080 min Summer 0.975 5240

15 min Winter 168.291 2930 min Winter 97.451 4360 min Winter 56.431 70120 min Winter 32.677 124


Friars Studio

3 Friar Gate

Derby DE1 1BU




Summary of Results for 100 year Return Period (+30%)


Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status

180 min Winter 98.793 0.793 94.8 2771.4 O K240 min Winter 98.797 0.797 95.0 2789.3 O K360 min Winter 98.793 0.793 94.8 2772.8 O K480 min Winter 98.785 0.785 94.2 2736.6 O K600 min Winter 98.771 0.771 93.2 2679.1 O K720 min Winter 98.754 0.754 92.0 2610.3 O K960 min Winter 98.728 0.728 90.0 2502.5 O K1440 min Winter 98.666 0.666 85.4 2255.3 O K2160 min Winter 98.578 0.578 78.2 1912.7 O K2880 min Winter 98.504 0.504 71.7 1637.9 O K4320 min Winter 98.377 0.377 58.7 1186.0 O K5760 min Winter 98.314 0.314 49.1 971.4 O K7200 min Winter 98.279 0.279 41.3 852.9 O K8640 min Winter 98.253 0.253 35.7 768.4 O K10080 min Winter 98.234 0.234 31.4 706.1 O K

Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)

180 min Winter 23.738 180240 min Winter 18.922 232360 min Winter 13.746 288480 min Winter 10.957 364600 min Winter 9.190 440720 min Winter 7.960 516960 min Winter 6.442 6621440 min Winter 4.782 9402160 min Winter 3.549 13322880 min Winter 2.873 17084320 min Winter 2.025 24245760 min Winter 1.580 31127200 min Winter 1.304 38248640 min Winter 1.114 451210080 min Winter 0.975 5248


Friars Studio

3 Friar Gate

Derby DE1 1BU




Model Details


Storage is Online Cover Level (m) 99.500

Tank or Pond Structure

Invert Level (m) 98.000

Depth (m) Area (m²) Depth (m) Area (m²)

0.000 2823.0 1.000 4516.0

Orifice Outflow Control

Diameter (m) 0.235 Discharge Coefficient 0.600 Invert Level (m) 98.000


Friars Studio

3 Friar Gate

Derby DE1 1BU




Summary of Results for 30 year Return Period


Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status



Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)




Friars Studio

3 Friar Gate

Derby DE1 1BU






Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status


Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)



Friars Studio

3 Friar Gate

Derby DE1 1BU




Model Details






0.000 2823.0 1.000 4516.0




Friars Studio

3 Friar Gate

Derby DE1 1BU






Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status



Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)




Friars Studio

3 Friar Gate

Derby DE1 1BU






Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status


Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)



Friars Studio

3 Friar Gate

Derby DE1 1BU




Model Details






0.000 2823.0 1.000 4516.0




Friars Studio

3 Friar Gate

Derby DE1 1BU






Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status



Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)




Friars Studio

3 Friar Gate

Derby DE1 1BU






Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status


Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)



Friars Studio

3 Friar Gate

Derby DE1 1BU




Model Details






0.000 2823.0 1.000 4516.0




Friars Studio

3 Friar Gate

Derby DE1 1BU


File North Pond(1in30... Checked by




Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status



Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)




Friars Studio

3 Friar Gate

Derby DE1 1BU






Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status


Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)



Friars Studio

3 Friar Gate

Derby DE1 1BU




Model Details






0.000 3503.0 1.000 5204.0




Friars Studio

3 Friar Gate

Derby DE1 1BU


File North Pond(1in2)... Checked by




Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status



Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)




Friars Studio

3 Friar Gate

Derby DE1 1BU






Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status


Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)



Friars Studio

3 Friar Gate

Derby DE1 1BU




Model Details






0.000 3503.0 1.000 5204.0




Friars Studio

3 Friar Gate

Derby DE1 1BU






Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status



Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)




Friars Studio

3 Friar Gate

Derby DE1 1BU






Storm

Event

Max

Level

(m)

Max

Depth

(m)

Max

Control

(l/s)

Max

Volume

(m³)

Status


Storm

Event

Rain

(mm/hr)

Time-Peak

(mins)



Friars Studio

3 Friar Gate

Derby DE1 1BU




Model Details






0.000 3503.0 1.000 5204.0



APPENDIX J

Greenfield Runoff Volumes


Friars Studio

3 Friar Gate

Derby DE1 1BU

Date 27/03/2013 00:24 Designed by Darren.St...

File Checked by


Greenfield Runoff Volume


FEH Data

Return Period (years) 100Storm Duration (mins) 360

Site Location GB 448300 335900 SK 48300 35900C(1km) -0.027D1(1km) 0.340D2(1km) 0.380D3(1km) 0.260E(1km) 0.305F(1km) 2.368

Areal Reduction Factor 1.00Area (ha) 28.000SAAR (mm) 639

CWI 94.020SPR Host 36.220

URBEXT (1990) 0.3163

Results

Percentage Runoff (%) 39.90Greenfield Runoff Volume (m³) 7141.279

Documents

ENVIRONMENT - WATERplanning.broxtowe.gov.uk/(S(xyjuqkzn3ejqsq3nk0esnemm))/Publish… · 3.2 A topographical survey of the wider site is included as Appendix E. 3.3 The model geometry