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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.
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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.
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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.
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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.
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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.
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
6
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.
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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.
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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.
TOTON LANE TECHNICAL NOTE 1: HYDROLOGY AND HYDRAULIC MODELLING
MARCH 2013 NTT301/TN1
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
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
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
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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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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
D2 value of 0.37304 used
D3 value of 0.26261 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
www.bwbconsulting.com
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
www.bwbconsulting.com
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
www.bwbconsulting.com
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
www.bwbconsulting.com
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.
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
A3
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
www.bwbconsulting.com
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
www.bwbconsulting.com
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
www.bwbconsulting.com
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
www.bwbconsulting.com
P1NTT/301/1302
PRELIMINARY
J. Green
D. Stewart
1:500
TOTON LANE SURVEY -
DITCH CROSSING 2
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.
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
A3
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
www.bwbconsulting.com
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
www.bwbconsulting.com
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
www.bwbconsulting.com
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
www.bwbconsulting.com
P1NTT/301/1301
PRELIMINARY
J. Green
D. Stewart
1:500
TOTON LANE SURVEY -
DITCH CROSSING 1
TOTON LANE
PEVERIL SECURITIES LTD
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
Q100+CC MANNINGS 0.06
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
Q100+CC MANNINGS 0.04
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
BWB Partnership Page 1
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:24 Designed by darren.st...
File South Pond(1in10... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 100 year Return Period (+30%)
©1982-2011 Micro Drainage Ltd
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
BWB Partnership Page 2
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:24 Designed by darren.st...
File South Pond(1in10... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 100 year Return Period (+30%)
©1982-2011 Micro Drainage Ltd
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
BWB Partnership Page 3
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:24 Designed by darren.st...
File South Pond(1in10... Checked by
Micro Drainage Source Control W.12.6.1
Model Details
©1982-2011 Micro Drainage Ltd
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
BWB Partnership Page 1
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:24 Designed by darren.st...
File South Pond(1in30... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 30 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
15 min Summer 98.283 0.283 36.3 866.6 O K30 min Summer 98.326 0.326 41.1 1010.3 O K60 min Summer 98.371 0.371 45.0 1162.2 O K120 min Summer 98.410 0.410 48.2 1300.6 O K180 min Summer 98.426 0.426 49.5 1357.5 O K240 min Summer 98.434 0.434 50.0 1384.2 O K360 min Summer 98.443 0.443 50.7 1417.6 O K480 min Summer 98.447 0.447 51.0 1432.6 O K600 min Summer 98.448 0.448 51.1 1434.9 O K720 min Summer 98.446 0.446 51.0 1428.8 O K960 min Summer 98.445 0.445 50.9 1424.6 O K1440 min Summer 98.432 0.432 49.9 1375.8 O K2160 min Summer 98.403 0.403 47.6 1273.8 O K2880 min Summer 98.374 0.374 45.3 1174.9 O K4320 min Summer 98.313 0.313 39.9 965.5 O K5760 min Summer 98.276 0.276 35.0 843.4 O K7200 min Summer 98.251 0.251 30.6 761.6 O K8640 min Summer 98.232 0.232 27.2 700.1 O K10080 min Summer 98.217 0.217 24.5 652.3 O K
15 min Winter 98.314 0.314 40.0 970.4 O K30 min Winter 98.362 0.362 44.3 1133.1 O K60 min Winter 98.412 0.412 48.3 1306.2 O K120 min Winter 98.457 0.457 51.8 1467.1 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
15 min Summer 85.265 2930 min Summer 50.510 4360 min Summer 29.922 70120 min Summer 17.726 126180 min Summer 13.049 180240 min Summer 10.500 212360 min Summer 7.730 272480 min Summer 6.220 340600 min Summer 5.256 408720 min Summer 4.579 476960 min Summer 3.742 6121440 min Summer 2.814 8802160 min Summer 2.117 12642880 min Summer 1.730 16444320 min Summer 1.236 23485760 min Summer 0.973 30647200 min Summer 0.809 38168640 min Summer 0.695 450410080 min Summer 0.612 5248
15 min Winter 85.265 2930 min Winter 50.510 4360 min Winter 29.922 70120 min Winter 17.726 124
BWB Partnership Page 2
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:24 Designed by darren.st...
File South Pond(1in30... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 30 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
180 min Winter 98.476 0.476 53.1 1536.6 O K240 min Winter 98.484 0.484 53.7 1565.0 O K360 min Winter 98.490 0.490 54.1 1586.9 O K480 min Winter 98.491 0.491 54.2 1589.8 O K600 min Winter 98.487 0.487 53.9 1576.2 O K720 min Winter 98.481 0.481 53.5 1553.1 O K960 min Winter 98.471 0.471 52.7 1517.4 O K1440 min Winter 98.441 0.441 50.6 1411.0 O K2160 min Winter 98.394 0.394 47.0 1243.7 O K2880 min Winter 98.353 0.353 43.5 1100.7 O K4320 min Winter 98.282 0.282 36.2 864.3 O K5760 min Winter 98.246 0.246 29.7 745.1 O K7200 min Winter 98.221 0.221 25.2 664.0 O K8640 min Winter 98.202 0.202 22.0 605.7 O K10080 min Winter 98.188 0.188 19.5 560.3 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
180 min Winter 13.049 178240 min Winter 10.500 230360 min Winter 7.730 288480 min Winter 6.220 364600 min Winter 5.256 440720 min Winter 4.579 514960 min Winter 3.742 6601440 min Winter 2.814 9382160 min Winter 2.117 13322880 min Winter 1.730 17084320 min Winter 1.236 24165760 min Winter 0.973 31287200 min Winter 0.809 38888640 min Winter 0.695 458410080 min Winter 0.612 5344
BWB Partnership Page 3
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:24 Designed by darren.st...
File South Pond(1in30... Checked by
Micro Drainage Source Control W.12.6.1
Model Details
©1982-2011 Micro Drainage Ltd
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) 0.204 Discharge Coefficient 0.600 Invert Level (m) 98.000
BWB Partnership Page 1
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:23 Designed by darren.st...
File South Pond(1in2)... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 2 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
15 min Summer 98.119 0.119 10.1 347.9 O K30 min Summer 98.145 0.145 15.1 426.1 O K60 min Summer 98.173 0.173 19.5 514.7 O K120 min Summer 98.201 0.201 24.6 602.0 O K180 min Summer 98.213 0.213 27.1 640.8 O K240 min Summer 98.222 0.222 28.9 666.8 O K360 min Summer 98.233 0.233 31.2 702.9 O K480 min Summer 98.239 0.239 32.6 724.1 O K600 min Summer 98.243 0.243 33.5 736.1 O K720 min Summer 98.245 0.245 33.8 741.9 O K960 min Summer 98.248 0.248 34.6 752.4 O K1440 min Summer 98.246 0.246 34.2 747.2 O K2160 min Summer 98.238 0.238 32.3 718.7 O K2880 min Summer 98.228 0.228 30.1 687.1 O K4320 min Summer 98.203 0.203 25.0 608.6 O K5760 min Summer 98.185 0.185 21.2 550.9 O K7200 min Summer 98.170 0.170 19.0 504.5 O K8640 min Summer 98.159 0.159 17.2 468.7 O K10080 min Summer 98.149 0.149 15.8 440.7 O K
15 min Winter 98.132 0.132 12.9 388.8 O K30 min Winter 98.161 0.161 17.6 476.6 O K60 min Winter 98.193 0.193 22.8 576.0 O K120 min Winter 98.223 0.223 29.2 672.8 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
15 min Summer 33.837 3030 min Summer 21.080 4360 min Summer 13.133 70120 min Summer 8.182 124180 min Summer 6.203 168240 min Summer 5.097 196360 min Summer 3.865 258480 min Summer 3.175 324600 min Summer 2.727 392720 min Summer 2.408 460960 min Summer 2.009 5921440 min Summer 1.556 8502160 min Summer 1.205 12242880 min Summer 1.006 15964320 min Summer 0.740 23405760 min Summer 0.595 30647200 min Summer 0.503 38168640 min Summer 0.438 450410080 min Summer 0.390 5248
15 min Winter 33.837 2930 min Winter 21.080 4360 min Winter 13.133 70120 min Winter 8.182 122
BWB Partnership Page 2
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:23 Designed by darren.st...
File South Pond(1in2)... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 2 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
180 min Winter 98.237 0.237 32.1 716.1 O K240 min Winter 98.245 0.245 33.8 741.4 O K360 min Winter 98.255 0.255 36.0 773.6 O K480 min Winter 98.259 0.259 36.9 786.4 O K600 min Winter 98.259 0.259 37.0 788.9 O K720 min Winter 98.258 0.258 36.8 785.4 O K960 min Winter 98.256 0.256 36.4 779.4 O K1440 min Winter 98.247 0.247 34.3 748.4 O K2160 min Winter 98.230 0.230 30.7 695.1 O K2880 min Winter 98.216 0.216 27.6 648.1 O K4320 min Winter 98.186 0.186 21.4 555.9 O K5760 min Winter 98.164 0.164 18.1 486.8 O K7200 min Winter 98.149 0.149 15.7 438.9 O K8640 min Winter 98.138 0.138 14.0 405.2 O K10080 min Winter 98.131 0.131 12.6 383.5 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
180 min Winter 6.203 174240 min Winter 5.097 198360 min Winter 3.865 272480 min Winter 3.175 346600 min Winter 2.727 418720 min Winter 2.408 490960 min Winter 2.009 6281440 min Winter 1.556 8922160 min Winter 1.205 12802880 min Winter 1.006 16524320 min Winter 0.740 24245760 min Winter 0.595 31287200 min Winter 0.503 38888640 min Winter 0.438 457610080 min Winter 0.390 5248
BWB Partnership Page 3
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:23 Designed by darren.st...
File South Pond(1in2)... Checked by
Micro Drainage Source Control W.12.6.1
Model Details
©1982-2011 Micro Drainage Ltd
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
BWB Partnership Page 1
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:23 Designed by darren.st...
File South Pond(1in1)... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 1 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
15 min Summer 98.095 0.095 6.4 275.3 O K30 min Summer 98.117 0.117 9.8 342.7 O K60 min Summer 98.142 0.142 14.7 419.3 O K120 min Summer 98.168 0.168 18.7 498.5 O K180 min Summer 98.181 0.181 20.6 537.8 O K240 min Summer 98.189 0.189 21.9 563.0 O K360 min Summer 98.200 0.200 24.3 598.4 O K480 min Summer 98.207 0.207 25.8 621.0 O K600 min Summer 98.212 0.212 26.8 635.0 O K720 min Summer 98.214 0.214 27.3 643.4 O K960 min Summer 98.219 0.219 28.2 658.0 O K1440 min Summer 98.220 0.220 28.5 661.3 O K2160 min Summer 98.214 0.214 27.3 643.5 O K2880 min Summer 98.207 0.207 25.7 619.7 O K4320 min Summer 98.186 0.186 21.4 553.7 O K5760 min Summer 98.169 0.169 18.8 501.5 O K7200 min Summer 98.156 0.156 16.8 462.4 O K8640 min Summer 98.147 0.147 15.4 432.8 O K10080 min Summer 98.139 0.139 14.2 409.5 O K
15 min Winter 98.106 0.106 7.7 307.9 O K30 min Winter 98.130 0.130 12.5 382.8 O K60 min Winter 98.159 0.159 17.2 468.9 O K120 min Winter 98.187 0.187 21.6 558.5 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
15 min Summer 26.669 3030 min Summer 16.831 4460 min Summer 10.623 70120 min Summer 6.704 124180 min Summer 5.122 180240 min Summer 4.231 202360 min Summer 3.233 262480 min Summer 2.670 328600 min Summer 2.303 396720 min Summer 2.040 462960 min Summer 1.711 5961440 min Summer 1.336 8542160 min Summer 1.043 12362880 min Summer 0.875 16004320 min Summer 0.648 23445760 min Summer 0.524 30647200 min Summer 0.445 38168640 min Summer 0.389 450410080 min Summer 0.347 5248
15 min Winter 26.669 3030 min Winter 16.831 4360 min Winter 10.623 70120 min Winter 6.704 124
BWB Partnership Page 2
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:23 Designed by darren.st...
File South Pond(1in1)... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 1 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
180 min Winter 98.201 0.201 24.6 601.9 O K240 min Winter 98.209 0.209 26.1 625.9 O K360 min Winter 98.219 0.219 28.4 660.0 O K480 min Winter 98.225 0.225 29.5 676.4 O K600 min Winter 98.227 0.227 29.9 683.1 O K720 min Winter 98.227 0.227 29.9 683.9 O K960 min Winter 98.227 0.227 30.0 684.7 O K1440 min Winter 98.221 0.221 28.8 665.6 O K2160 min Winter 98.209 0.209 26.1 625.5 O K2880 min Winter 98.197 0.197 23.6 587.7 O K4320 min Winter 98.170 0.170 18.9 503.0 O K5760 min Winter 98.151 0.151 16.0 445.2 O K7200 min Winter 98.138 0.138 14.1 406.1 O K8640 min Winter 98.130 0.130 12.5 381.4 O K10080 min Winter 98.124 0.124 11.1 362.9 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
180 min Winter 5.122 176240 min Winter 4.231 202360 min Winter 3.233 274480 min Winter 2.670 350600 min Winter 2.303 422720 min Winter 2.040 494960 min Winter 1.711 6321440 min Winter 1.336 8982160 min Winter 1.043 12842880 min Winter 0.875 16684320 min Winter 0.648 24205760 min Winter 0.524 31207200 min Winter 0.445 38248640 min Winter 0.389 451210080 min Winter 0.347 5256
BWB Partnership Page 3
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:23 Designed by darren.st...
File South Pond(1in1)... Checked by
Micro Drainage Source Control W.12.6.1
Model Details
©1982-2011 Micro Drainage Ltd
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
BWB Partnership Page 1
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:25 Designed by darren.st...
File North Pond(1in30... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 30 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
15 min Summer 98.340 0.340 68.7 1290.2 O K30 min Summer 98.390 0.390 83.7 1494.8 O K60 min Summer 98.438 0.438 95.1 1698.3 O K120 min Summer 98.475 0.475 100.9 1857.7 O K180 min Summer 98.488 0.488 102.8 1913.8 O K240 min Summer 98.497 0.497 104.1 1949.8 O K360 min Summer 98.504 0.504 105.2 1982.8 O K480 min Summer 98.504 0.504 105.2 1983.2 O K600 min Summer 98.500 0.500 104.6 1965.9 O K720 min Summer 98.494 0.494 103.7 1938.2 O K960 min Summer 98.485 0.485 102.3 1896.9 O K1440 min Summer 98.457 0.457 98.1 1780.1 O K2160 min Summer 98.418 0.418 91.7 1612.3 O K2880 min Summer 98.388 0.388 83.2 1488.8 O K4320 min Summer 98.333 0.333 66.5 1260.2 O K5760 min Summer 98.296 0.296 55.5 1112.1 O K7200 min Summer 98.270 0.270 47.9 1008.3 O K8640 min Summer 98.250 0.250 42.0 928.9 O K10080 min Summer 98.234 0.234 37.4 864.8 O K
15 min Winter 98.377 0.377 79.9 1443.1 O K30 min Winter 98.432 0.432 94.1 1673.5 O K60 min Winter 98.487 0.487 102.7 1908.3 O K120 min Winter 98.531 0.531 109.0 2098.2 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
15 min Summer 85.265 2930 min Summer 50.510 4260 min Summer 29.922 68120 min Summer 17.726 122180 min Summer 13.049 154240 min Summer 10.500 184360 min Summer 7.730 252480 min Summer 6.220 320600 min Summer 5.256 388720 min Summer 4.579 454960 min Summer 3.742 5881440 min Summer 2.814 8422160 min Summer 2.117 12122880 min Summer 1.730 15724320 min Summer 1.236 23005760 min Summer 0.973 30487200 min Summer 0.809 37528640 min Summer 0.695 449610080 min Summer 0.612 5248
15 min Winter 85.265 2930 min Winter 50.510 4260 min Winter 29.922 68120 min Winter 17.726 120
BWB Partnership Page 2
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:25 Designed by darren.st...
File North Pond(1in30... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 30 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
180 min Winter 98.543 0.543 110.8 2153.1 O K240 min Winter 98.549 0.549 111.6 2180.7 O K360 min Winter 98.551 0.551 111.8 2187.2 O K480 min Winter 98.543 0.543 110.8 2153.5 O K600 min Winter 98.531 0.531 109.1 2101.4 O K720 min Winter 98.518 0.518 107.2 2040.8 O K960 min Winter 98.495 0.495 103.9 1943.8 O K1440 min Winter 98.449 0.449 96.7 1743.5 O K2160 min Winter 98.396 0.396 85.5 1519.0 O K2880 min Winter 98.359 0.359 74.5 1367.3 O K4320 min Winter 98.299 0.299 56.4 1123.6 O K5760 min Winter 98.262 0.262 45.6 976.4 O K7200 min Winter 98.237 0.237 38.2 876.5 O K8640 min Winter 98.215 0.215 33.1 790.7 O K10080 min Winter 98.197 0.197 29.4 723.1 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
180 min Winter 13.049 168240 min Winter 10.500 194360 min Winter 7.730 270480 min Winter 6.220 344600 min Winter 5.256 416720 min Winter 4.579 488960 min Winter 3.742 6241440 min Winter 2.814 8822160 min Winter 2.117 12522880 min Winter 1.730 16204320 min Winter 1.236 23485760 min Winter 0.973 30727200 min Winter 0.809 38248640 min Winter 0.695 458410080 min Winter 0.612 5328
BWB Partnership Page 3
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:25 Designed by darren.st...
File North Pond(1in30... Checked by
Micro Drainage Source Control W.12.6.1
Model Details
©1982-2011 Micro Drainage Ltd
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 3503.0 1.000 5204.0
Orifice Outflow Control
Diameter (m) 0.290 Discharge Coefficient 0.600 Invert Level (m) 98.000
BWB Partnership Page 1
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:25 Designed by darren.st...
File North Pond(1in2)... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 2 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
15 min Summer 98.144 0.144 16.3 521.0 O K30 min Summer 98.174 0.174 25.2 636.8 O K60 min Summer 98.208 0.208 32.7 766.3 O K120 min Summer 98.240 0.240 40.0 891.0 O K180 min Summer 98.254 0.254 44.2 945.5 O K240 min Summer 98.264 0.264 47.1 983.5 O K360 min Summer 98.277 0.277 51.0 1034.4 O K480 min Summer 98.284 0.284 53.1 1062.5 O K600 min Summer 98.287 0.287 54.1 1076.8 O K720 min Summer 98.289 0.289 54.6 1082.4 O K960 min Summer 98.291 0.291 55.3 1092.4 O K1440 min Summer 98.287 0.287 54.1 1076.9 O K2160 min Summer 98.275 0.275 50.5 1029.0 O K2880 min Summer 98.263 0.263 46.8 979.7 O K4320 min Summer 98.233 0.233 38.1 861.9 O K5760 min Summer 98.210 0.210 33.1 773.7 O K7200 min Summer 98.193 0.193 29.4 709.6 O K8640 min Summer 98.181 0.181 26.7 661.9 O K10080 min Summer 98.172 0.172 24.5 626.2 O K
15 min Winter 98.160 0.160 21.0 582.0 O K30 min Winter 98.194 0.194 29.6 711.9 O K60 min Winter 98.232 0.232 37.9 857.4 O K120 min Winter 98.267 0.267 48.0 995.7 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
15 min Summer 33.837 3030 min Summer 21.080 4360 min Summer 13.133 70120 min Summer 8.182 124180 min Summer 6.203 160240 min Summer 5.097 188360 min Summer 3.865 254480 min Summer 3.175 320600 min Summer 2.727 388720 min Summer 2.408 454960 min Summer 2.009 5861440 min Summer 1.556 8422160 min Summer 1.205 12162880 min Summer 1.006 15884320 min Summer 0.740 23365760 min Summer 0.595 30567200 min Summer 0.503 37608640 min Summer 0.438 449610080 min Summer 0.390 5160
15 min Winter 33.837 2930 min Winter 21.080 4260 min Winter 13.133 68120 min Winter 8.182 122
BWB Partnership Page 2
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:25 Designed by darren.st...
File North Pond(1in2)... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 2 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
180 min Winter 98.281 0.281 52.3 1053.4 O K240 min Winter 98.291 0.291 55.3 1091.6 O K360 min Winter 98.302 0.302 58.6 1133.5 O K480 min Winter 98.305 0.305 59.5 1146.9 O K600 min Winter 98.305 0.305 59.5 1146.0 O K720 min Winter 98.302 0.302 58.7 1137.2 O K960 min Winter 98.299 0.299 57.7 1122.3 O K1440 min Winter 98.286 0.286 53.7 1069.5 O K2160 min Winter 98.265 0.265 47.4 986.9 O K2880 min Winter 98.247 0.247 42.1 917.2 O K4320 min Winter 98.210 0.210 33.0 772.8 O K5760 min Winter 98.186 0.186 27.8 679.2 O K7200 min Winter 98.170 0.170 24.0 621.2 O K8640 min Winter 98.160 0.160 21.1 583.3 O K10080 min Winter 98.153 0.153 18.9 554.4 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
180 min Winter 6.203 170240 min Winter 5.097 194360 min Winter 3.865 268480 min Winter 3.175 342600 min Winter 2.727 414720 min Winter 2.408 484960 min Winter 2.009 6201440 min Winter 1.556 8822160 min Winter 1.205 12642880 min Winter 1.006 16444320 min Winter 0.740 23845760 min Winter 0.595 31127200 min Winter 0.503 38168640 min Winter 0.438 450410080 min Winter 0.390 5248
BWB Partnership Page 3
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:25 Designed by darren.st...
File North Pond(1in2)... Checked by
Micro Drainage Source Control W.12.6.1
Model Details
©1982-2011 Micro Drainage Ltd
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 3503.0 1.000 5204.0
Orifice Outflow Control
Diameter (m) 0.298 Discharge Coefficient 0.600 Invert Level (m) 98.000
BWB Partnership Page 1
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:24 Designed by darren.st...
File North Pond(1in1)... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 1 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
15 min Summer 98.115 0.115 10.5 412.3 O K30 min Summer 98.142 0.142 15.8 512.9 O K60 min Summer 98.172 0.172 24.0 626.0 O K120 min Summer 98.201 0.201 30.3 740.2 O K180 min Summer 98.216 0.216 33.3 795.1 O K240 min Summer 98.225 0.225 35.3 832.7 O K360 min Summer 98.239 0.239 38.8 884.9 O K480 min Summer 98.247 0.247 41.1 916.2 O K600 min Summer 98.252 0.252 42.5 935.1 O K720 min Summer 98.254 0.254 43.3 945.5 O K960 min Summer 98.259 0.259 44.6 963.4 O K1440 min Summer 98.259 0.259 44.6 962.8 O K2160 min Summer 98.251 0.251 42.3 931.9 O K2880 min Summer 98.241 0.241 39.5 894.7 O K4320 min Summer 98.215 0.215 33.1 791.8 O K5760 min Summer 98.195 0.195 29.0 717.0 O K7200 min Summer 98.181 0.181 26.0 662.1 O K8640 min Summer 98.170 0.170 23.7 621.8 O K10080 min Summer 98.163 0.163 21.6 592.1 O K
15 min Winter 98.128 0.128 12.6 461.2 O K30 min Winter 98.157 0.157 20.1 572.8 O K60 min Winter 98.191 0.191 28.0 699.6 O K120 min Winter 98.224 0.224 35.1 829.2 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
15 min Summer 26.669 3030 min Summer 16.831 4360 min Summer 10.623 70120 min Summer 6.704 124180 min Summer 5.122 170240 min Summer 4.231 196360 min Summer 3.233 258480 min Summer 2.670 324600 min Summer 2.303 392720 min Summer 2.040 460960 min Summer 1.711 5901440 min Summer 1.336 8482160 min Summer 1.043 12242880 min Summer 0.875 15964320 min Summer 0.648 23365760 min Summer 0.524 30567200 min Summer 0.445 37608640 min Summer 0.389 449610080 min Summer 0.347 5240
15 min Winter 26.669 3030 min Winter 16.831 4360 min Winter 10.623 70120 min Winter 6.704 122
BWB Partnership Page 2
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:24 Designed by darren.st...
File North Pond(1in1)... Checked by
Micro Drainage Source Control W.12.6.1
Summary of Results for 1 year Return Period
©1982-2011 Micro Drainage Ltd
Storm
Event
Max
Level
(m)
Max
Depth
(m)
Max
Control
(l/s)
Max
Volume
(m³)
Status
180 min Winter 98.240 0.240 39.2 890.3 O K240 min Winter 98.249 0.249 41.8 926.0 O K360 min Winter 98.261 0.261 45.3 973.2 O K480 min Winter 98.267 0.267 46.9 994.1 O K600 min Winter 98.268 0.268 47.3 1000.8 O K720 min Winter 98.268 0.268 47.2 999.5 O K960 min Winter 98.267 0.267 47.0 996.3 O K1440 min Winter 98.259 0.259 44.6 962.7 O K2160 min Winter 98.243 0.243 40.0 900.0 O K2880 min Winter 98.227 0.227 35.7 840.3 O K4320 min Winter 98.195 0.195 28.9 714.4 O K5760 min Winter 98.174 0.174 24.5 634.3 O K7200 min Winter 98.161 0.161 21.2 586.7 O K8640 min Winter 98.152 0.152 18.7 553.0 O K10080 min Winter 98.145 0.145 16.8 527.4 O K
Storm
Event
Rain
(mm/hr)
Time-Peak
(mins)
180 min Winter 5.122 174240 min Winter 4.231 198360 min Winter 3.233 272480 min Winter 2.670 346600 min Winter 2.303 418720 min Winter 2.040 488960 min Winter 1.711 6261440 min Winter 1.336 8902160 min Winter 1.043 12762880 min Winter 0.875 16564320 min Winter 0.648 23845760 min Winter 0.524 31127200 min Winter 0.445 38168640 min Winter 0.389 450410080 min Winter 0.347 5248
BWB Partnership Page 3
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 12/03/2013 15:24 Designed by darren.st...
File North Pond(1in1)... Checked by
Micro Drainage Source Control W.12.6.1
Model Details
©1982-2011 Micro Drainage Ltd
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 3503.0 1.000 5204.0
Orifice Outflow Control
Diameter (m) 0.290 Discharge Coefficient 0.600 Invert Level (m) 98.000
APPENDIX J
Greenfield Runoff Volumes
BWB Partnership Page 1
Friars Studio
3 Friar Gate
Derby DE1 1BU
Date 27/03/2013 00:24 Designed by Darren.St...
File Checked by
Micro Drainage Source Control W.12.6.1
Greenfield Runoff Volume
©1982-2011 Micro Drainage Ltd
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