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Technical Note

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Project: Lochgelly Cycle Track Job No: 60504172

Subject: Surface Water Drainage Design: Planning Revision: Rev 3

Prepared by: Aisling Marlow Date: 01/07/2016

Checked by: Natasha Mukalenga Date: 04/07/2016

Approved by: Jim Pearson Date: 04/07/2016

Revised by James Tunnicliffe (Rev 3) Date: 18/10/2016

1. Revision 3 Notes on Changes to Design

The principal changes to this Technical Note are summarised as follows:

· SuDS design storm event is now 1:100 year;

· Outfalls from the SuDS to the existing water courses have been limited to the greenfield run off equivalentof 4l/s/ha;

· The proposed culverts have been sized so as not to increase the risk of flooding for a 1:200 year stormevent plus a 20% climate change allowance; and

· The detention basin at the unnamed burn has been taken off line from the burn diversion.

It should be noted that while this development is within an area that is at risk from flooding, this note demonstratesthat the scheme does not increase flood risk elsewhere and the operator (Fife Council) will manage the residualflood risk for this low vulnerability site.

2. Introduction

This technical note sets out the steps and methodologies adopted during the outline design for surface waterdrainage and watercourse crossings for the proposed Lochgelly Cycle Track. This technical note will summarisethe delivery of the following services:

· Catchment modelling and analysis;

· Hydraulic modelling and analysis including flooding analysis, and flood risk assessment to allowcompliance with the planning comments in the planning extract below;

· Drainage design incorporating SuDS features to attenuate flow and allow permissible discharge into theburn and Scottish Water sewer;

· Culvert design for where the circuit crosses the watercourse;

· Assessment of the capacity of the existing culvert under the B920.

3. Design Guidance:

A likely range of flows have been estimated using a combination of industry standard design guidance including:

· Kerby-Hatheway Time of Concentration Method (overland flows), 1959;· Flood Estimation Handbook, Rainfall-Runoff Method, Centre for Ecology & Hydrology, 1999;· The Modified Rational Method, as implemented in the Wallingford Procedure;· Culvert design and operation guide, CIRIA, 2010;· SuDS Manual, CIRIA, 2015.

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4. Abbreviations

FEH Flood Estimation Handbook.

UWCI Urban Catchment Wetness Index.

SAAR Seasonally Adjusted Annual Rate.

SuDS Sustainable urban Drainage Systems.

CIRIA Construction Industry Research and Information Association.

OS Ordinance Survey.

HEC RAS Hydrologic Engineering Center's River Analysis System.

FRM Flood Risk Management.

5. Run Off Flow Estimation Methodology

1:25,000 OS maps in addition the FEH CD ROM were used to delineate the likely catchments draining to site. FromFEH and contour assessment the catchment of the unnamed burn flowing through site was delineated. Looking atthis catchment in the context of the site it was modified to exclude areas which would drain to the Burn prior toreaching the site i.e. would not drain to site (Figure 1).

Figure 1: Catchment of Burn and Catchment affecting Proposed Development

The wider catchment draining to the site was further delineated using available topographic survey (provided by FifeCouncil) to estimate likely overland flow paths on site. This enabled the efficient placement of drainage features and

Overall Catchment ofProposed Development

Catchment of unnamed Burn

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A

B

C

D

more accurate assessment of flows to be stored / attenuated within these features at these subcatchments. Thesesubcatchments are illustrated in Figure 2.

Figure 2: Subcatchments affecting the Proposed Development

The Modified Rational Method, as implemented in the Wallingford Procedure, was used to assess runoff from thecatchment. This method was developed for urban runoff assessment and is a simple and widely used method forthis type of application. It was deemed suitable given the main change in the area will be to add large areas ofimpervious material to the currently rural site. A number of sources were used to obtain the relevant information forapplication of this hydrological model including;

· Winter Rainfall Acceptance Potential Maps which determined the water holding capacity of the soil;

· UWCI graphs from the SuDS Manual to provide an Urban Catchment Wetness Index (UCWI);

· FEH CD ROM which provided figures for SAAR (to obtain UCWI) and rainfall depths so that intensities fordifferent storm durations could be calculated;

· OS mapping to determine area of the site and percentage area of impermeable surfaces.

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The modified rational method was implemented for the greenfield catchment draining to site i.e. current levels ofimpermeable areas taken into account. The method was then repeated considering only the new areas to beconstructed on site i.e. cycle track and carpark, assuming a worst case that 100% of the new area would beimpermeable. The difference between these results is the runoff volume arising from the site that would need to beattenuated/stored in order to discharge the excess surface water at greenfield run off rates. This method wascarried out for the overall catchment and for the subcatchments illustrated in Figure 2.

The Kerby-Hatheway (overland flows) method to calculate time of concentration was used to provide a suitablerange of storm duration to determine critical storm duration for short, intense events which would result in largeflows. Once the critical duration was obtained, the flow estimation via Modified Rational Method was carried out fora range of return periods (1:2 – 1:200) as illustrated in Table 1 below. The critical storm duration for the overallcatchment was found to be 15mins giving a maximum greenfield flow (1:2) to site of 8.1l/s/ha and runoff volume of263m3. Looking at the cycle track in isolation, the cycle track will generate a flow of 60.9l/s/ha and runoff volume of179m3, meaning the cycle track will require a total of 179m3 to be stored for a 1:2 year event across the site in orderto ensure the condition is kept at like for like conditions. It has been assumed that flows will be attenuated/stored todischarge at like for like greenfield runoff rates e.g. that the 1:100 year volume of surface water drainage for thescheme which will likely be discharged to the unnamed burn or Lochfitty Burn is equal to the greenfield 1:100 yearevent. These shorter durations have been used to size critical conveyance infrastructure such as swales as theyresult in high flow rates which need to be attenuated appropriately to greenfield runoff rates. The drainage proposalalso contains features which provide flow control through storage and therefore attenuation of stormwater runoff(detention basins). These features have been sized to accommodate the volume of run off arising from thedevelopment

Table 1 below shows the peak discharge and maximum volume that may need to be designed for the overallcatchment based on for a range of return periods.

Table 1: Peak Discharge and Volumes for Overall Catchment

AnnualExceedanceProbability

(AEP%)RP Rainfall

(mm)i

(mm/hr)

Greenfield Runoff OverallCatchment

Proposed DevelopmentRunoff

Qp(l/s)

Volume(m3)

Qp(l/s/ha)

Qp(l/s)

Volume(m3)

Qp(l/s/ha)

50 2 5 20 380 263 8 259 179 61

20 5 7 27 509 352 11 347 240 82

10 10 8 32 616 426 13 420 291 99

3.33 30 11 44 836 579 18 570 395 134

2 50 13 50 950 657 20 648 448 152

1 100 15 60 1148 794 25 783 542 184

0.5 200 18 72 1376 952 29 939 649 220

20% CC 1651 1142 35 1126 779 264

30% CC 1789 1238 38 1220 844 284

A check has been carried out for longer duration events, as these are likely to be more critical to storing capacity ofdrainage features given they will result in larger volumes. In order to ensure suitable sizing of infrastructure, a 6hour critical duration was considered as this is in line with CIRIA guidance on Greenfield Runoff Estimation which isused to define the allowable runoff volume which can be discharged (at greenfield flow rates) from a developmentsite in order to protect downstream areas from increased flood risk due to the development. The 6 hour durationevent is based on the need to provide adequate protection for small to medium sized watercourses that tend to bemost at risk from the effects of development. Given the small size of this watercourse and the fact that a 6.75hrstorm duration was shown to be critical to the unnamed burn on site, it was decided that this would be anappropriate long duration event for investigation.

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The total storage volume provided by drainage proposed on site (swales, soakaway and detention basins) is2264m3, therefore, at a 1:30 year event where the volume of run off arising from the development of 1534m3 issuitably provided for. Appropriate storage has been provided up to a 1:200 year event where a volume of 2260m3

arises from the development.

6. Culvert Design

6.1. Hydraulic Modelling

An estimation of the existing culvert capacity has been made through hydraulic modelling. A model has been built inHEC RAS software by using topographic survey supplied by Fife Council to represent river cross-sections from200m upstream of the B920 to the assumed culvert outlet at the Lochfitty Burn. Figure 3 illustrates the location ofmodelled cross-sections. HEC-RAS is designed to perform one-dimensional hydraulic calculations for a network ofnatural and constructed channels.

Given the lack of survey information for the culvert and unconfirmed path, the existing culvert has been modelled asinlet controlled so that all the losses are defined at the culvert entrance and throughout the culvert. The topographyof the area suggests that the Burn follows a 90 degree bend to discharge to the Lochfitty Burn at the boundary ofAlmar Cottage.

This has been assumed as OS mapping indicates that ground levels fall in this direction and site inspectionrevealed that the potential straight line path of the culvert to the Lochfitty Burn would involve following risingtopography before ground levels fall steeply towards the Burn. To account for this in the model the maximum exitloss of 1.0 has been applied to the culvert outlet.

Cross-section

Site boundary

Culvert crossing

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Figure 3: Modelled Cross-section Locations

6.2. Model Parameters

Inflows to the Burn have been estimated using the catchment previously delineated using OS mapping and FEH CDROMs to represent all flow which is likely to flow downstream to the Burn along the site. An FEH Rainfall Runoffbased approach using hydrological models was adopted as this is more appropriate for smaller catchments (lessthan 20km2) that are more likely to experience a catchment-wide design storm. Other rainfall runoff methods suchas Revitalised Rainfall Runoff and IH024 method for small catchments were also applied to provide a confidencelevel for the FEH estimated flows. FEH Rainfall runoff was deemed to be the most suitable as it provided a mediumvalue for flow between the two estimates.

Furthermore, FEH ReFEH2 has not been fully assessed as yet by SEPA for its suitably for Scottish catchmenttherefore does not have full confidence attached to it. Peak flows for 1:2 to 1:200 year are illustrated in the tablebelow.

Table 2: Peak Flows into Unnamed Burn

Return Period Flow FEH RR m3/s(Adopted)

Flow FEHReFEH2 (m3/s)

IH024(m3/s)

2 0.68 0.89 0.595 0.94 1.15 0.7210 1.14 1.34 0.9230 1.51 1.63 1.2350 1.70 1.78 1.41

100 1.95 2.03 1.70200 2.26 2.32 2.06

200+20% forclimate change

2.71 2.78 2.47

The model inflows were applied to the upstream end of the model. A normal depth based on the bed slope wasapplied at the downstream boundary of the model. Normal depth was deemed an appropriate boundary condition inlieu of surveyed information or recorded downstream water levels at the outlet to the Lochfitty Burn. The bed slopeacross the modelled reach was measured to be approximately 0.0104.

The Manning’s Equation is used in HEC RAS to estimate flow depths in river reaches assuming normal flowconditions. Manning’s ‘n’ values are used in this equation to reflect the roughness of the flow channels. LargeManning’s ‘n’ values imply higher degrees of roughness and consequently higher flood levels. From site inspectionthe channel roughness values were set at 0.045 representing a relatively straight channel with weeds and stones torepresent the overgrown nature of the channel observed on site. The floodplain was observed to be pasture withshort grass and no brush therefore overbank areas were set to 0.03. These values are within the rangerecommended in standard references such as Chow, 1959, and are considered conservative. As the culvert couldnot be inspected on site, a conservative manning’s value of 0.013 was adopted to represent a concrete culvert with‘bends, connections and some debris’. The existing culvert which inlets at the B920 have been modelled as a1.2*0.8m rectangular box culvert based on site inspection and consultation with Fife Council. Baseline modellinghas indicated that the existing culvert is overtopped at a 1:10 flood event suggesting a maximum flow capacity of1.1m3/s. This is in line with anecdotal flood evidence and SEPA FRM maps. The channel is highly variable in termsof capacity becoming much more constricted towards the east end of the site with the conveyance area reducingfrom 7m2 at the entrance of the Burn on site to reducing to 2.81m2 at the centre of the site. Modelling indicates thatthese more constricted reaches at the centre of the site towards the culvert inlet have the potential to be overtoppedfrom a 1:5 year event, whereas the upper reaches of the Burn on site will contain storm events of up to 1:100 year.

Given the current restrictions in the Burn, an appropriate culvert sizing for the necessary two crossing locations forthe cycle track must be adopted to ensure that the existing conveyance capacity of the channel is matched. Again,given the uncertainty in the outlet of the Burn the culverts have been designed as inlet controlled. As such given themajority of the channel and culvert inlet is able to convey a flow of 1:10 year storm event, the culvert has been

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conservatively designed to convey a 1:200 year storm event flow plus 20% allowance for climate change (2.71m3/s)as the baseline condition.

It has been decided that a rectangular box culvert formation would be most suitable, as it provides a larger channelcapacity than a pipe. Although a pipe arrangement can be more suitable in terms Low Flows issues in terms of fishpassage this is not applicable to the watercourse. Providing a box culvert will also allow safer inspection andmaintenance procedures which is likely to be a key driver given that the main issue for culvert blockage is likely tobe overgrowth in the downstream reaches of the channel during dry periods.

As the probability of debris causing a blockage is small, the flood risk is small as due to the culvert sizing and thereis no justification for a trash screen for security purposes it has been decided that a trash screen is not neededgiven the short and straight length of the culverts and their setting under a rural cycle track.

It was deemed more cost efficient and conservative to adopt the same sizing of culverts throughout the track. Theculverts have been sized using CIRIA Culvert design and operation guidance, to be 1.5 by 1m rectangular concretesingle barrel box culvert with 0 degree flared wingwalls with top edge square. A freeboard of 0.25m will also beadded to the culvert in accordance with Environment Agency Guidance resulting in box culvert of 1.8m by 1mrequirement for each of the two crossings. Given that these culverts have been sized for flood events greater thanthe Burn is currently capable of conveying, it is unlikely that this change to the watercourse will increase flood riskon site or downstream.

The proposed culverts were then represented in the baseline hydraulic modelling in order to assess the impact onflood levels of this intervention. The proposed arrangement of 1.8 by 1m was modified to 2m by 1m arrangement asthis resulted in less change in flood level along the Burn as is deemed to be a more standard size of culvert to besourced. As can be seen from Table 3, for the most part the new culvert arrangement causes a negligible change(less than 50mm) or decrease in flood level. For the most part, at a 1:30 year event the introduction of culverts hascaused no noticeable change on flood level, however, at the upstream extent of the model, flood level is shown toincrease by 500mm. Although this increase in flood level is significant, water is predicted to remain within bank.Therefore as no spillage occurs, this represents no change to the overall flood risk of the area. At higher returnperiods, the increase in flood level in the upstream extents of the model is less extreme (300mm) and with flow stillretained within bank indicating that the flood risk to the site should remain unchanged up to a 1:200 year event.

Baseline modelling in partnership with SEPA FRM maps has shown the capacity of the Burn to be limited to 1:10year event. The Burn is predicted to overtop at a 1:10 year event, indicating that the introduction of Culvert 1 hasactually increased the conveyance capacity of the channel at this point allowing more flow to pass forward andallowing flow to be retained in bank at this return period. Therefore although flood level may increase at higherreturn period events, the Burn naturally struggles to convey flows of these magnitudes, therefore the introduction ofculverts does not change the quantified flood risk of 1:10 year.

A core requirement of Scottish Planning Policy is that flood risk from the development should not be increasedelsewhere. Modelling predicts that culverting of the watercourse at these two locations using a the 2*1m box culvertarrangement (which includes allowance for freeboard) does not alter flood risk downstream as flood levels arepredicted to remain the same up to the 1:200 year event. Overtopping of the existing culvert inlet is predicted at a1:10 year event onwards and this remains unchanged with the introduction of the new culvert crossings.

At greater return period events, spill over the existing culvert inlet becomes more dominant in driving flooding thanthe new culvert arrangement. The new arrangement actually causes a reduction in flood level at a 1:50 year and nochange at a 1:200 year event as a greater volume of flow is able to be taken by the channel due to increaseconveyance capacity offered by the new culverts. At a 1:200 year event, the flow is such that it dominates waterlevels causing a general increase in flood level over the modelled reach of the Burn of 20 to 300mm. This is likelydue to the existing culvert being overwhelmed by this volume of flow causing back up of flow along the watercourse.This mechanism is shown to be largely unchanged by the presence of culverts. Although the flood level at theupstream extent is shown to increase more significantly the Burn under baseline conditions is already overtopped,therefore the likelihood of flooding is unchanged meaning there is no change in flood risk. Furthermore, as themajority of the channel and culvert inlet is able to convey a flow of 1:10 year storm event, the culvert has beenconservatively designed to convey a 1:200 (+20%cc) year storm event flow (2.71m3/s) as the baseline condition.Any flow above this return period will overwhelm the new culverts similarly to how it would overwhelm the Burn atbaseline condition.

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Table 3: Change in Flood Level Compared to Baseline Condition

LocationChange in Flood Level with new arrangements (mm)

2 5 10 30 50 100 2008 -660 190 -760 480 -50 -300 1507 180 -650 -620 -30 -510 -370 306 0 -900 -550 0 0 -310 305 0 10 -1010 0 0 10 204 0 10 -160 0 0 10 203 0 0 0 0 -80 10 202 380 0 0 0 10 -1920 20

1.5 0 0 -3620 0 0 0 201 0 0 0 0 0 0 20

0.5 0 -350 -430 0 -470 -330 00 0 0 10 0 0 0 0

As stated previously, this hydraulic model has been used to give a simplistic estimate on the impact of the schemeon flood risk and has been based on a number of assumptions, the most substantial of which being the assumedroute of the culvert and its outfall location.

This has the potential to add large amount of uncertainty to the results given the predicted flooding from theLochfitty Burn from high likelihood events (1:10) is likely to be a control on flooding through high tail water levels inthe culvert. However, this assessment has increased confidence that the culvert sizing designed using CIRIAguidance is suitable for flows on site, with a low likelihood of increasing flood risk downstream. AECOM wouldrecommend full survey of the existing culvert and its outlet to Lochfitty Burn to increase confidence in thisassessment. Furthermore, AECOM would recommend a survey of cross-sections within the Burn upstream of thesite in order to investigate the occurrence of afflux and assess whether the new development increase flood riskupstream.

The design aims to be compliant with Scottish Planning Policy in terms of Clause 255 so a precautionary approachto flood risk from all sources has been undertaken during this design with a focus on flood avoidance by attemptingto safeguard to conveying capacity of the channel by providing box culverts of suitable capacity where crossings arerequired. Despite its location in a high to medium risk area, the cycle track can still be considered appropriate for thearea as it would be considered a low vulnerability development under Scottish Planning Policy. In addition, hydraulicmodelling has been used as a design aid to check that the development does not alter this existing flood risk fromthe Lochfitty Burn.

Flood reduction has been considered in the detailed design from outline design by removing the need for fourculvert crossings to two. Furthermore, the design of a Sustainable Drainage Systems (SuDS) has been providedwhere areas of impermeable surface are to be added in order to not increase greenfield runoff. A Level 1 Flood RiskAssessment has also been provided for the proposed development as it lies in the medium to high risk area.

6.3. Sensitivity Analysis

Sensitivity analysis was undertaken on the baseline model in the absence of any calibration data.

Channel and floodplain roughness in the 1D model was increased and decreased by 20% to establish whether themodel was sensitive to variation or uncertainty in roughness. Depths along the modelled stretch increased byapproximately 40mm when roughness was raised and decreased by approximately 20mm when roughness wasreduced for the 1 in 200yr event. The model was shown to be slightly more sensitive to changes in roughness in theupper region of the model with alterations of around 100mm predicted for the 1 in 200yr event when roughness wasincreased and decreased. In the context of flood risk, these variations can be considered negligible therefore thelack of sensitivity to a change in parameters reduces model uncertainty and the 1D model is considered to bereliable.

The downstream boundary (Normal Depth) was also increased and decreased by 20% to establish whether themodel was sensitive to variation in gradient. Depths along the modelled stretch were unchanged for both these

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alterations except isolated variations at the upstream extent of the model. Depths along this stretch of the reachdecreased by approximately 90mm when normal depth was increased for the 1 in 200yr event and reduced by10mm when the normal depth was decreased. These minor variations indicate that the model is insensitive to thedownstream boundary condition.

The existing culvert inlet at the east of the site is considered to have a significant influence on flood risk, therefore itwas considered necessary to undertake a sensitivity test on the impact of blockage here. For a 20% blockagemodelling indicates this has little impact on flood risk with a maximum increase in flood level of 70mm along thereach. However, with a more significant 50% blockage, flood level is significantly increased with a 1m increasepredicted along the reach upstream of the inlet. From site inspection, the culvert was shown to be partially blockedwith overgrowth, which appeared to cover approximately 20% of the inlet. It has been assumed that this sensitivitywill be applicable to the whole reach, as such an allowance for freeboard (0.25m) will be included for the newcrossings.

7. Parameters and Assumptions for SuDS Outline Design

The outline design was produced using various elements in the CIRIA SuDS Manual 2015 and the results of thehydrology report depicting flows and volumes for pre and post development runoff.

The aim for the SuDS design is to keep the peak runoff rate for the proposed development equal to or less than thegreenfield (pre development) peak runoff rate and to contain and treat the increased runoff volume from theproposed development with the SuDS components. The design of the SuDS system will produce peak flows of lessthan or equal to the greenfield peak runoff rate for the different rainfall events up to the 100 year storm event.

7.1. Parameters

Parameters for Outline SuDS Design:

· Vegetated Conveyance and Attenuation Swales

o The design follows Fife Council’s preferred solution to implement these types of swales as theycan be designed to treat and provide some attenuation. Where attenuation is not sufficient theswales will flow to other SuDS components;

o Bottom width of the swales to be between 0.5m and 2m. Current design considers most swaleswith a 2m bottom width for maximum attenuation and flow capacity;

o The longitudinal slopes of the swales in general follow the cycle path slopes. Where the slope isgreater than 4% check dams will be implemented to optimize the swales functions as intended;

o The side slopes of the swales to be 1:4 as shallower slopes support pre-treatment, reduce healthand safety risks, and assist maintenance;

o Swale depths will be kept to a maximum of 300mm depth where applicable. Swales which haveinlet pipes have been limited in numbers;

o Swales were designed to treat the 1:2 year storm event and manage the capacity for the 1:100year storm using the Rational Method and Mannings equation.

o Swales have been sized to convey a 1:100 year event flow and have been shown to provideappropriate storage, in combination with other features, for the additional volumes of run offarising from the development at the target 100 year storm event.

· Filter Strips

o The grass verge of the cycle track will act as a filter strip and be used as pre-treatment for rainfallevents before falling to either swales or filter drains;

o Slopes of the filter strips will be a maximum of 5%. In most cases the filter strip is 2.5% for 3mand 1% for 1m before reaching another SuDS component;

o The filter strips will encourage sedimentation and filtration for better runoff water quality.

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· Filter Drains

o The design incorporates filter drains on this site where space was minimal in lieu of swales. Thefilter drains will allow for attenuation and conveyance of runoff to downstream SuDS components;

o The filter material will be designed for adequate percolation for water quality and storage volumebased on void ratio using Darcy’s Law;

o The filter drains were designed for the 1:100 year storm event.· Vegetated Detention/Retention Basins

o There will be three detention/retention basins to control the runoff flow and volume from theproposed development. The base of the basin to be 1:100 slope for water quality and to promoteinterception in small rain events;

o The detention/retention basin sized to suit the volume from the 100 year storm plus 30%;

o Side slopes are 1:4 to support pre-treatment, reduce health and safety risks, assist maintenance,and improve aesthetics;

o Detention basins in combination with other proposed drainage features have been shown to storeadditional runoff volume arising from the development at the target 100 year storm event;

o The outlet controls the peak runoff rates to the equivalent 4l/s/ha for the 100 year storm.· Soakaways

o Soakaways have been removed from the scheme on the basis that the expected groundconditions will not allow for efficient percolation.

7.2. Assumptions

Assumptions:

· Outline design is only for planning purposes. Not for construction;· Earthworks implemented to best promote flow to SuDS components;· Groundwater table a minimum of 1m below SuDS components;· The car park drains away from the existing road;· The cross section of the cycle track and grass verges slope in the same direction;· The north basin is assumed to be able to outlet to the Lochfitty Burn;

· The south basin is assumed to outlet into the existing channel. At present we assume that channeleventually outlets to the Lochfitty Burn;

· The Health and Safety elements associated with detention basin will be addressed by Fife Council.

8. Design Data Received From Fife Council

8.1. Instructed Design RequirementsA list of the instructed design requirements as communicated by Fife Council:

· Track design undertaken by Fife Council;· Road Width – 6m wide;· 3m wide berm to be incorporated at the edge of the road surface;· Road Running Surface – Impermeable;· Lighting Standards;· Road Cross fall – The circuit is to have a crossfall of 1 in 40 except on the bends where it is to be 1 in 20;· The cycling authorities’ guidance stating flat top edge kerbs or no kerbs.

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8.2. Design LimitationsA list of the design limitations include:

· No realignment of the proposal tack has been undertaken by AECOM;

· No construction details have been provided for the parking areas.

8.3. Data ReceivedThe following data have been received from Fife Council:

Table 4: Drawings Received from Fife Council

Description Date Received

Lochgelly Cycle Track Drawings and Surveys:

42645 Lochgelly Cycle Track; 43381 Lochgelly Cycle Track Extension; 43971 LochgellyCycle Track Extension 2.

2016/05/04

Layout of cycle track: CE02 03 rev D. 2016/05/05

Revised copy of the cycle track layout drawing with chainages included. 2016/05/18

Lochgelly cycle track with proposed lighting – lighting spillage. 2016/06/03

Revised Layout of cycle track: CE02 03 rev E. 2016/06/03

Revised Layout of cycle track: CE02 03 rev F. 2016/09/23

Table 5: Guidance Documents Received from Fife Council

Description Date Received

Draft British Cycling: Closed Road Racing Circuits Technical Guidance. 2016/05/04

DLM Mineral Position Report Site 2. 2016/05/04

2245 MRA Lochgelly Stn Road Cycle Track Option to North:

“Report on the Mineral Position Relative to an Area of Ground to the North of LochgellyHigh School, by Station Road, Lochgelly, Fife, for a Proposed Closed Road CyclingLoop Within Lochore Meadows”.

2016/05/04

9. Risk LogRefer to attached risk register in Appendix A.

10. CalculationsRefer to attached hydrology calculation in Appendix B.

Refer to attached SuDS calculation in Appendix C.

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APPENDIX A: RISK REGISTER

Risk Register

Project Number 60504172 Design Manager

Project Title

Cost Time

1

Risks associated with stagnant

water. Due to higher than design

frequency combined with poor

infiltration of ground.

Medium High High Risk Medium High

Design to ensure minimise

the risk of stagnating water

but to prescribed standards.

Health and safety risk of contamination

and visually unsatisfactory to the

public.

Fife Council

2

Risk of overflow associated with

exceedance flow (design

exceedance event).

High High High Risk Medium MediumDesigned to address

prescribed standards.

Increased likelihood of pluvial surface

water flooding with exceedance flows.Fife Council

3No survey information for culvert

inlet.High High High Risk Medium Low

Contractor to be appointed to

undertake survey

investigation of culvert inlet.

No survey information for culvert inlet

therefore potential losses at the inlet

are only estimated based on site

observations altering prediction of flow

regime and flood level.

Fife Council

4No survey information for culvert

route. High High High Risk Low High

Contractor to be appointed to

undertake survey

investigation of culvert route.

If the route is longer or has more

bends than assumed losses are likely

to be greater altering prediction of flow

regime and flood level.

Fife Council

5 No survey information for the outlet. High High High Risk Low HighFife Council to undertake

survey investigation of outlet.

Given there is a high likelihood of

flooding (1.10) from the assumed

outfall Lochfitty Burn, it is likely that

this is a control for flood levels (high

tail water levels causing backwater

effect) in the unnamed Burn culvert

therefore without having accurate

survey of the outlet the prediction of

flood level at the Burn is quite

uncertain.

Fife Council

6

The unknown discharge to the Burn

witnessed on site. (Note this outside

the scope of this project).

High High High Risk Low Medium

No recommendation made at

this stage as this is outside

the scope of this project.

The unknown discharge to the Burn

witnessed on site throws off

calculations of flows through the Burn

which are based on what would

naturally drain to the Burn.

Fife Council/Others

7 Soil type unknown. High High High Risk Medium HighContractor to undertake

percolation/ infiltration tests.

Soil type unknown percolation and

infiltration capacity based on high level

WRAP maps.

Fife Council

8

SuDS components sized for

Proposed Site Drainage areas not

the entire drainage catchment.

High High High Risk Medium High

Contractor to undertake topo

for the surrounding areas.

Client/Contractor to provide

GIS information and appoint

a contractor.

Only existing topo for the site not the

surrounding areas and there is no

existing GIS information available

about where the water could possibly

be collected before it reaches the

proposed development and diverted

away.

Fife Council

9 Safety issues. Medium MediumModerate

Risk Medium High

Minimise or design out risks

so that SuDS features pose

little or no health and safety

risk. Include fencing/barriers

and signage to prevent

drowning by denying access.

Council to advise/instruct for any

additional safety features they may

consider.

Fife

Council/Consultant

10Confined spaces (inadvertent public

access).Medium Medium

Moderate

Risk Medium High

Contractor to assess any

confined spaces and provide

the appropriate mitigation

measures. Contractor to

ensure personnel/site staff

are aware and using safe

systems of work.

Risk of asphyxiation, toxic gas

inhalation, falling/drowning while

working within confined spaces.

Contractor

11Construction area in/near public

roads.Medium Medium

Moderate

Risk Medium High

Contractor to provide traffic

management plan and traffic

control in compliance with the

Local Planning Authority (and

other Stakeholders as

required).

Traffic disturbance and danger to the

general public, road users and site

staff.

Contractor

12 Excavations. Medium MediumModerate

Risk High High

Contractor to install

protection in the perimeter of

the excavation. Contractor to

use precaution signs and

ensure safe systems of work.

Risk of injuries from collapse of trench

walls or from fall/slip/trip.Contractor

13Slips, trips and falls (including falling

objects/materials).Medium Medium

Moderate

Risk Medium High

Contractor to ensure safe

systems of work, good

housekeeping, site

awareness and duty of care

for others. Site personnel

should wear appropriate

PPE.

Potential for personnel to slip, trip, or

fall on site. All

14Adverse weather conditions

impacting completion of works.Medium Medium

Moderate

Risk Medium High

Weather conditions to be

monitored and recorded on

site and notified where

considered exceptional.

Working in wet or dark conditions

leading to slips, falls, trips,

mishandling of equipment/machinery.

Adverse weather resulting in delays

and downtime on site.

All

15Overhead services and existing

utilities.Medium Medium

Moderate

Risk High High

Contractor to undertake site

investigation to identify

existing overhead lines

positions and heights.

Electrocution. Fife Council

16

Contact with surface/underground

discharge. (Water quality - health

risk).

Medium MediumModerate

Risk Medium High

Contractor to ensure site

personnel wear PPE and

other appropriate body

protection.

Residual risk of contact with

surface/underground discharge.All

17 Maintenance during operations. Medium MediumModerate

Risk Medium High

Regular maintenance to be

undertaken to ensure the

assets function as per

design.

Lack of maintenance will result in

inadequate function of site drainage

assets.

Fife Council

Risk ID Description P/I Score Impact

Probability Impact Response Strategy Effect Risk Owner

Fife Council Jim Pearson

Lochgelly Cycling Circuit - Risk Register - Rev00

Client Contact

File: Lochgelly Cycling Circuit - Risk Register - Draft REV00.xls

Date Printed: 27/06/2016 UNCONTROLLED WHEN PRINTED

Version: 1.0 / Mar 10

AECOM

Technical Note

13

APPENDIX B: HYDROLOGY CALCULATIONS

Time of Concentration (Tc) Calculations Overall Catchment Draining to Site

Tc is used to determine the most appropriate storm duration to use.

Calculations Remarks/Output

Equations

Tc = 0.00025 (L / √S)^0.8 Kirpich (channel flows)

Tc = (2.L.N / 3√S)^(1/2.14) Kerby-Hatheway (overland flows)

Variables

L 473 m (length)

S 0.038055 (slope)

N 0.2 (Kerby's roughness parameter)

Based on longest stream length

Topo Survey and British Geo Survey OS DTMFor pavement; could be 0.2 for "rough surface"

For pasture grass could be 0.2

Calculations

Tc = 0.127545 hours

7.652717 minutes Tc (Kirpich) = 7 minutes

Tc = 14.88359 minutes Tc (Kerby-Hatheway) = 6 minutes with N = 0.02

Tc (Kerby-Hatheway) = 15 minutes with N = 0.2

Based on the above assessment, Tc is likely to be in the range of 6-15 minutes

5 minutes seems short considering the catchment, so a design value of 15 minutes will be used.

The potential impact of uncertainty should be considerd for subsequent calculations.

A

B

C

D

Status of Design: Detail, Design Manager / PM: Jim Pearson, Designer: Aisling Marlow

Rational method runoff calculations Overall Catchment Draining to Site (Pre-development)

Cv calculated using Wallingford Procedure, using the whole catchment (not just impervious areas)


Equations

Q = 2.78 * C I A

C = Cv Cr

Cv = PR / 100 5.75 total impermaebale area

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7 0.1231263 % imp

Variables

Area A 46.7 Ha Based on hydrological assessment

PIMP 12 % (% impermeable) assumed based on imp area before dev

WRAP class 4 WRAP soil maps

SOIL 0.45 (WRAP soil class 4)

SAAR 891 mm FEH CD - some variability, conservative

UCWI (summer) 95 Fig 4.6 CIRIA C697 (SuDS manual)

UCWI (winter) 138 Fig 4.6 CIRIA C697 (SuDS manual)

Cr 1.3 Wallingford procedure recommended value

Summer Winter

PR 7.908 11.262 %

Cv 0.07908 0.11262

C 0.102804 0.14641

Storm duration: 5 min summer

RP Rainfall (mm) i (mm/hr) Qp (l/s) Volume (m3)

2 2.9 34.8 464 107 9.95

5 4 48 641 148 13.72

10 5.5 66 881 203 18.86

30 6.8 81.6 1089 251 23.32

50 7.8 93.6 1249 288 26.75

100 9.5 114 1522 351 32.58

200 11.5 138 1842 425 39.44 166.08

0.5%CC 2210 510 20% climate change allowance




2 4.1 24.6 328 151 7.03

5 5.5 33 440 203 9.43

10 6.8 40.8 545 251 11.66

30 9.2 55.2 737 340 15.78

50 10.6 63.6 849 391 18.18

100 12.7 76.2 1017 469 21.78

200 15.4 92.4 1233 569 26.41





2 5 20 267 185 5.72

5 6.7 26.8 358 247 7.66

10 8.1 32.4 432 299 9.26

30 11 44 587 406 12.57

50 12.5 50 667 462 14.29

100 15.1 60.4 806 558 17.26

200 18.1 72.4 966 668 20.69



Storm duration: 5 min winter


2 2.9 34.8 661 153 14.16

5 4 48 912 210 19.54


10 5.5 66 1254 289 26.86

30 6.8 81.6 1551 358 33.21

50 7.8 93.6 1779 410 38.10

100 9.5 114 2167 500 46.40

200 11.5 138 2623 605 56.17




RP Rainfall (mm) i (mm/hr) Qp (l/s) Volume (m3)Qp (l/s/ha)

2 4.1 24.6 468 216 10.01

5 5.5 33 627 289 13.43

10 6.8 40.8 775 358 16.61

30 9.2 55.2 1049 484 22.47

50 10.6 63.6 1209 557 25.89

100 12.7 76.2 1448 668 31.01

200 15.4 92.4 1756 810 37.61





2 5 20 380 263 8.14

5 6.7 26.8 509 352 10.91

10 8.1 32.4 616 426 13.19

30 11 44 836 579 17.91

50 12.5 50 950 657 20.35

100 15.1 60.4 1148 794 24.58

200 18.1 72.4 1376 952 29.47



Most likley time of concentration

given basline condition is pasture

grass.


Rational method runoff calculations Overall Catchment Draining to Site (Post Development)



total impermaeble without track, 4.26

Equations

Q = 2.78 * C I A

C = Cv Cr

Cv = PR / 100

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7

Variables

Area A 4.26 Ha Area of cycle track and carpark

PIMP 100 % (% impermeable) Conservatively assumed



SAAR 891 mm FEH CD - some variability




Summer Winter

PR 80.86 84.214 %

Cv 0.8086 0.84214

C 1.05118 1.09478



2 2.9 34.8 433 100

5 4 48 598 138

10 5.5 66 822 189

30 6.8 81.6 1016 234

50 7.8 93.6 1165 269

100 9.5 114 1419 327

200 11.5 138 1718 396





2 4.1 24.6 306 141

5 5.5 33 411 189

10 6.8 40.8 508 234

30 9.2 55.2 687 317

50 10.6 63.6 792 365

100 12.7 76.2 949 437

200 15.4 92.4 1150 530





2 5 20 249 172

5 6.7 26.8 334 231

10 8.1 32.4 403 279

30 11 44 548 379

50 12.5 50 622 431

100 15.1 60.4 752 520

200 18.1 72.4 901 623






2 2.9 34.8 451 104

5 4 48 622 144

10 5.5 66 856 197

30 6.8 81.6 1058 244

50 7.8 93.6 1214 280

100 9.5 114 1478 341

200 11.5 138 1789 413





2 4.1 24.6 319 147 75

5 5.5 33 428 197 100

10 6.8 40.8 529 244 124

30 9.2 55.2 716 330 168

50 10.6 63.6 825 380 194

100 12.7 76.2 988 456 232

200 15.4 92.4 1198 552 281





2 5 20 259 179 61

5 6.7 26.8 347 240 82

10 8.1 32.4 420 291 99

30 11 44 570 395 134

50 12.5 50 648 448 152

100 15.1 60.4 783 542 184

200 18.1 72.4 939 649 220

0.5%CC 1126 7790.5%CC 1220 844

20% climate change allowance 30% climate change allowance


Time of Concentration (Tc) Calculations Subcatchment A



Equations



Variables

L 350 m (length) Based on longest stream length

S 0.008571 (slope) Topo survey and British Geological Survey DTM

N 0.2 (Kerby's roughness parameter) For pavement; could be 0.02 for "rough surface"

pasture grass 0.2

Calculations

Tc = 0.181959 hours


Tc = 18.31645 minutes Tc (Kerby-Hatheway) = 6 minutes with N = 0.02





A

B

C

D


Rational method runoff calculations Predevelopment Subcatchment A

Cv calculated using Wallingford Procedure, using the whole subcatchment (not just impervious areas)


Equations

Q = 2.78 * C I A

C = Cv Cr

Cv = PR / 100

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7

Variables





SAAR 891 mm FEH CD - some variability




Summer Winter

PR 0.447 3.801 %

Cv 0.00447 0.03801

C 0.005811 0.04941

Rainfall depths obtained from FEH CD


RP Rainfall (mm) i (mm/hr) Qp (l/s) Volume (m3) Qp (l/s/ha)

2 2.9 34.8 6 1 0.56

5 4 48 9 2 0.78

10 5.5 66 12 3 1.07

30 6.8 81.6 15 3 1.32

50 7.8 93.6 17 4 1.51

100 9.5 114 20 5 1.84

200 11.5 138 25 6 2.23





2 4.1 24.6 4 2 0.40

5 5.5 33 6 3 0.53

10 6.8 40.8 7 3 0.66

30 9.2 55.2 10 5 0.89

50 10.6 63.6 11 5 1.03

100 12.7 76.2 14 6 1.23

200 15.4 92.4 17 8 1.49





2 5 20 4 2 0.32

5 6.7 26.8 5 3 0.43

10 8.1 32.4 6 4 0.52

30 11 44 8 5 0.71

50 12.5 50 9 6 0.81

100 15.1 60.4 11 7 0.98

200 18.1 72.4 13 9 1.17





2 2.9 34.8 53 12 4.78

5 4 48 73 17 6.59


10 5.5 66 101 23 9.07

30 6.8 81.6 124 29 11.21

50 7.8 93.6 143 33 12.86

100 9.5 114 174 40 15.66

200 11.5 138 210 48 18.96





2 4.1 24.6 37 17 3.38 Most realistic estimate

5 5.5 33 50 23 4.53

10 6.8 40.8 62 29 5.60

30 9.2 55.2 84 39 7.58

50 10.6 63.6 97 45 8.74

100 12.7 76.2 116 54 10.47

200 15.4 92.4 141 65 12.69





2 5 20 30 21 2.75

5 6.7 26.8 41 28 3.68

10 8.1 32.4 49 34 4.45

30 11 44 67 46 6.04

50 12.5 50 76 53 6.87

100 15.1 60.4 92 64 8.30

200 18.1 72.4 110 76 9.95




Rational method runoff calculations Post Development Subcatchment A

Cv calculated using Wallingford Procedure, using just impervious areas to be added for development


Equations

Q = 2.78 * C I A

C = Cv Cr 4.297 area of track and carpark

Cv = PR / 100 1.052 lies in Catchment A

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7

Variables





SAAR 891 mm FEH CD - some variability,




Summer Winter

PR 80.86 84.214 %

Cv 0.8086 0.84214

C 1.05118 1.09478


RP Rainfall (mm) i (mm/hr) Qp (l/s) Volume (m3)Qp (l/s\ha)

2 2.9 34.8 107 25 102

5 4 48 148 34 140

10 5.5 66 203 47 193

30 6.8 81.6 251 58 238

50 7.8 93.6 288 66 274

100 9.5 114 350 81 333

200 11.5 138 424 98 403





2 4.1 24.6 76 35 72

5 5.5 33 101 47 96

10 6.8 40.8 125 58 119

30 9.2 55.2 170 78 161

50 10.6 63.6 196 90 186

100 12.7 76.2 234 108 223

200 15.4 92.4 284 131 270





2 5 20 61 43 58

5 6.7 26.8 82 57 78

10 8.1 32.4 100 69 95

30 11 44 135 94 129

50 12.5 50 154 106 146

100 15.1 60.4 186 128 177

200 18.1 72.4 223 154 212





2 2.9 34.8 111 26 106

5 4 48 154 35 146


10 5.5 66 211 49 201

30 6.8 81.6 261 60 248

50 7.8 93.6 300 69 285

100 9.5 114 365 84 347

200 11.5 138 442 102 420





2 4.1 24.6 79 36 75

5 5.5 33 106 49 100

10 6.8 40.8 131 60 124

30 9.2 55.2 177 82 168

50 10.6 63.6 204 94 194

100 12.7 76.2 244 113 232

200 15.4 92.4 296 136 281

0.5%CC 355 164

0.5%CC 385 177




2 5 20 64 44 61

5 6.7 26.8 86 59 82

10 8.1 32.4 104 72 99

30 11 44 141 97 134

50 12.5 50 160 111 152

100 15.1 60.4 193 134 184

200 18.1 72.4 232 160 220




Time of Concentration (Tc) Calculations Subcatchment B



Equations



Variables

L 483 m

S 0.047619

N 0.2

(length) Based on longest stream length

(slope) From topo survey and BGS DTM(Kerby's roughness parameter) 0.2 For grass could be 0.02 for " pavement"

Calculations

Tc = 0.118573 hours


Tc = 14.26276 minutes Tc (Kerby-Hatheway) = 15 minutes with N =0.2





A

B

C

D


Rational method runoff calculations Predevelopment Subcatchment C



Equations

Q = 2.78 * C I A

C = Cv Cr

Cv = PR / 100

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7

Variables





SAAR 891 mm FEH CD - some variability, conservative estimate




Summer Winter

PR 7.908 11.262 %

Cv 0.07908 0.11262

C 0.102804 0.14641

Rainfall depth from FEH CD



2 2.9 34.8 329 76 10

5 4 48 454 105 14

10 5.5 66 624 144 19

30 6.8 81.6 772 178 23

50 7.8 93.6 885 204 27

100 9.5 114 1078 249 33

200 11.5 138 1305 301 39





2 4.1 24.6 233 107 7

5 5.5 33 312 144 9

10 6.8 40.8 386 178 12

30 9.2 55.2 522 241 16

50 10.6 63.6 602 277 18

100 12.7 76.2 721 332 22

200 15.4 92.4 874 403 26





2 5 20 189 131 6

5 6.7 26.8 254 175 8

10 8.1 32.4 306 212 9

30 11 44 416 288 13

50 12.5 50 473 327 14

100 15.1 60.4 571 395 17

200 18.1 72.4 685 474 21





2 2.9 34.8 469 108 14

5 4 48 647 149 20


10 5.5 66 889 205 27

30 6.8 81.6 1099 253 33

50 7.8 93.6 1261 291 38

100 9.5 114 1536 354 46

200 11.5 138 1859 429 56





2 4.1 24.6 331 153 10

5 5.5 33 445 205 13

10 6.8 40.8 550 253 17

30 9.2 55.2 744 343 22

50 10.6 63.6 857 395 26

100 12.7 76.2 1027 473 31

200 15.4 92.4 1245 574 38





2 5 20 269 186 8

5 6.7 26.8 361 250 11

10 8.1 32.4 436 302 13

30 11 44 593 410 18

50 12.5 50 674 466 20

100 15.1 60.4 814 563 25

200 18.1 72.4 975 675 29




Rational method runoff calculations Post Development Subcatchment B

Cv calculated using Wallingford Procedure, using just impervious areas to be added for development


Equations

Q = 2.78 * C I A


Cv = PR / 100 0.4 lies in Catchment B

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7

Variables









Summer Winter

PR 80.86 84.214 %

Cv 0.8086 0.84214

C 1.05118 1.09478



2 2.9 34.8 41 9 102

5 4 48 56 13 140

10 5.5 66 77 18 193

30 6.8 81.6 95 22 238

50 7.8 93.6 109 25 274

100 9.5 114 133 31 333

200 11.5 138 161 37 403





2 4.1 24.6 29 13 72

5 5.5 33 39 18 96

10 6.8 40.8 48 22 119

30 9.2 55.2 65 30 161

50 10.6 63.6 74 34 186

100 12.7 76.2 89 41 223

200 15.4 92.4 108 50 270



Storm duration: 15 min summer Qp (l/s/ha)


2 5 20 23 16 58

5 6.7 26.8 31 22 78

10 8.1 32.4 38 26 95

30 11 44 51 36 129

50 12.5 50 58 40 146

100 15.1 60.4 71 49 177

200 18.1 72.4 85 59 212





2 2.9 34.8 42 10 106

5 4 48 58 13 146


10 5.5 66 80 19 201

30 6.8 81.6 99 23 248

50 7.8 93.6 114 26 285

100 9.5 114 139 32 347

200 11.5 138 168 39 420





2 4.1 24.6 30 14 75

5 5.5 33 40 19 100

10 6.8 40.8 50 23 124

30 9.2 55.2 67 31 168

50 10.6 63.6 77 36 194

100 12.7 76.2 93 43 232

200 15.4 92.4 112 52 281





2 5 20 24 17

5 6.7 26.8 33 23

10 8.1 32.4 39 27

30 11 44 54 37

50 12.5 50 61 42

100 15.1 60.4 74 51

200 18.1 72.4 88 61




Time of Concentration (Tc) Calculations Subcatchment C



Equations



Variables

L 176.4 m (length) Based on longest stream length

S 0.039683 (slope) Topo survey and British Geological Survey OS DTM

N 0.2 (Kerby's roughness parameter) For grass could be 0.2, 0.02 for "rough pavement"

Calculations

Tc = 0.056977 hours







A

B

C

D


Rational method runoff calculations Predevelopment Subcatchment C



Equations 0.1184 IMP

Q = 2.78 * C I A 0.07

C = Cv Cr 6.58

Cv = PR / 100

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7

Variables



WRAP class 4 WRAP soil maps (could be part 4/5 but 5 is conservative)






Summer Winter

PR 3.763 7.117 %

Cv 0.03763 0.07117

C 0.048919 0.09252



2 2.9 34.8 9 2 5

5 4 48 12 3 7

10 5.5 66 16 4 9

30 6.8 81.6 20 5 11

50 7.8 93.6 23 5 13

100 9.5 114 28 6 16

200 11.5 138 34 8 19





2 4.1 24.6 6 3 3

5 5.5 33 8 4 4

10 6.8 40.8 10 5 6

30 9.2 55.2 14 6 8

50 10.6 63.6 16 7 9

100 12.7 76.2 19 9 10

200 15.4 92.4 23 10 13





2 5 20 5 3 3

5 6.7 26.8 7 5 4

10 8.1 32.4 8 5 4

30 11 44 11 7 6

50 12.5 50 12 8 7

100 15.1 60.4 15 10 8

200 18.1 72.4 18 12 10





2 2.9 34.8 16 4 9

5 4 48 22 5 12


10 5.5 66 31 7 17

30 6.8 81.6 38 9 21

50 7.8 93.6 43 10 24

100 9.5 114 53 12 29

200 11.5 138 64 15 35





2 4.1 24.6 11 5 6

5 5.5 33 15 7 8

10 6.8 40.8 19 9 10

30 9.2 55.2 26 12 14

50 10.6 63.6 29 14 16

100 12.7 76.2 35 16 20

200 15.4 92.4 43 20 24





2 5 20 9 6 5

5 6.7 26.8 12 9 7

10 8.1 32.4 15 10 8

30 11 44 20 14 11

50 12.5 50 23 16 13

100 15.1 60.4 28 19 16

200 18.1 72.4 34 23 19




Rational method runoff calculations Post Development Subcatchment C

Cv calculated using Wallingford Procedure, impervious areas to be added for development


Equations

Q = 2.78 * C I A


Cv = PR / 100 0.7 lies in Catchment C

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7

Variables









Summer Winter

PR 80.86 84.214 %

Cv 0.8086 0.84214

C 1.05118 1.09478



2 2.9 34.8 71 16 102

5 4 48 98 23 140

10 5.5 66 135 31 193

30 6.8 81.6 167 38 238

50 7.8 93.6 191 44 274

100 9.5 114 233 54 333

200 11.5 138 282 65 403





2 4.1 24.6 50 23 72

5 5.5 33 68 31 96

10 6.8 40.8 83 38 119

30 9.2 55.2 113 52 161

50 10.6 63.6 130 60 186

100 12.7 76.2 156 72 223

200 15.4 92.4 189 87 270





2 5 20 41 28 58

5 6.7 26.8 55 38 78

10 8.1 32.4 66 46 95

30 11 44 90 62 129

50 12.5 50 102 71 146

100 15.1 60.4 124 85 177

200 18.1 72.4 148 102 212





2 2.9 34.8 74 17 106

5 4 48 102 24 146


10 5.5 66 141 32 201

30 6.8 81.6 174 40 248

50 7.8 93.6 199 46 285

100 9.5 114 243 56 347

200 11.5 138 294 68 420





2 4.1 24.6 52 24 75

5 5.5 33 70 32 100

10 6.8 40.8 87 40 124

30 9.2 55.2 118 54 168

50 10.6 63.6 135 62 194

100 12.7 76.2 162 75 232

200 15.4 92.4 197 91 281

0.5%CC 236 109

0.5%CC 256 118




2 5 20 43 29 61

5 6.7 26.8 57 39 82

10 8.1 32.4 69 48 99

30 11 44 94 65 134

50 12.5 50 107 74 152

100 15.1 60.4 129 89 184

200 18.1 72.4 154 107 220




Time of Concentration (Tc) Calculations Subcatchment D



Equations



Variables

L 119.3 m (length) Based on longest stream length

S 0.025147 (slope) Topo and British Geological Survey OS DTM

N 0.2 (Kerby's roughness parameter) For grass could be 0.2, 0.02 for " rough pavement"

Calculations

Tc = 0.05001 hours







A

B

C

D


Rational method runoff calculations Pre Development Subcatchment D



Equations 0.17 total impervious area in Sub D

Q = 2.78 * C I A

C = Cv Cr

Cv = PR / 100

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7

Variables


PIMP 14.8 % (% impermeable) Conservatively assumed






Cr 1.3 Wallingford procedure recommended value, typically used for design

Summer Winter

PR 10.2292 13.5832 %

Cv 0.102292 0.13583

C 0.1329796 0.17658



2 2.9 34.8 15 3 13

5 4 48 20 5 18

10 5.5 66 28 6 24

30 6.8 81.6 35 8 30

50 7.8 93.6 40 9 35

100 9.5 114 48 11 42

200 11.5 138 58 13 51





2 4.1 24.6 10 5 9

5 5.5 33 14 6 12

10 6.8 40.8 17 8 15

30 9.2 55.2 23 11 20

50 10.6 63.6 27 12 24

100 12.7 76.2 32 15 28

200 15.4 92.4 39 18 34





2 5 20 8 6 7

5 6.7 26.8 11 8 10

10 8.1 32.4 14 9 12

30 11 44 19 13 16

50 12.5 50 21 15 18

100 15.1 60.4 26 18 22

200 18.1 72.4 31 21 27





2 2.9 34.8 20 5 17

5 4 48 27 6 24


10 5.5 66 37 9 32

30 6.8 81.6 46 11 40

50 7.8 93.6 53 12 46

100 9.5 114 64 15 56

200 11.5 138 78 18 68





2 4.1 24.6 14 6 12 most realistic based on roughness

5 5.5 33 19 9 16

10 6.8 40.8 23 11 20

30 9.2 55.2 31 14 27

50 10.6 63.6 36 17 31

100 12.7 76.2 43 20 37

200 15.4 92.4 52 24 45





2 5 20 11 8 10

5 6.7 26.8 15 10 13

10 8.1 32.4 18 13 16

30 11 44 25 17 22

50 12.5 50 28 19 25

100 15.1 60.4 34 24 30

200 18.1 72.4 41 28 36




Rational method runoff calculations Post Development Subcatchment D

Cv calculated using Wallingford Procedure, impervious areas of the development in this Catchment only


Equations

Q = 2.78 * C I A


Cv = PR / 100 0.27 lies in Catchment D

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7

Variables









Summer Winter , typically used for design

PR 80.86 84.214 %

Cv 0.8086 0.84214

C 1.05118 1.09478



2 2.9 34.8 27 6 102

5 4 48 38 9 140

10 5.5 66 52 12 193

30 6.8 81.6 64 15 238

50 7.8 93.6 74 17 274

100 9.5 114 90 21 333

200 11.5 138 109 25 403





2 4.1 24.6 19 9 72

5 5.5 33 26 12 96

10 6.8 40.8 32 15 119

30 9.2 55.2 44 20 161

50 10.6 63.6 50 23 186

100 12.7 76.2 60 28 223

200 15.4 92.4 73 34 270



Storm duration: 15 min summer Qp (l/s/ha)


2 5 20 16 11 58

5 6.7 26.8 21 15 78

10 8.1 32.4 26 18 95

30 11 44 35 24 129

50 12.5 50 39 27 146

100 15.1 60.4 48 33 177

200 18.1 72.4 57 40 212





2 2.9 34.8 29 7 106

5 4 48 39 9 146


10 5.5 66 54 13 201

30 6.8 81.6 67 15 248

50 7.8 93.6 77 18 285

100 9.5 114 94 22 347

200 11.5 138 113 26 420





2 4.1 24.6 20 9 75

5 5.5 33 27 13 100

10 6.8 40.8 34 15 124

30 9.2 55.2 45 21 168

50 10.6 63.6 52 24 194

100 12.7 76.2 63 29 232

200 15.4 92.4 76 35 281

0.5%CC 91 42

0.5%CC 99 46




2 5 20 16 11 61

5 6.7 26.8 22 15 82

10 8.1 32.4 27 18 99

30 11 44 36 25 134

50 12.5 50 41 28 152

100 15.1 60.4 50 34 184

200 18.1 72.4 59 41 220




Rational method runoff calculations



Equations

Q = 2.78 * C I A

C = Cv Cr total impermaeble 4.297ha

Cv = PR / 100

PR = 0.829 PIMP + 25 SOIL + 0.078 UCWI - 20.7

Variables

Area A 4.297 Ha Area of cycle track and carpark








Summer Winter

PR 80.86 84.214 %

Cv 0.8086 0.84214

C 1.05118 1.09478



2 21.9 3.65 48 792 11.11 Rainfall depths from FEH DDF Rainfall

5 28.1 4.68333 61 1017 14.25 modelling 6hr duration

10 33.1 5.51667 72 1198 16.79

30 42.4 7.06667 92 1534 21.51

50 47.5 7.91667 104 1719 24.09

100 55.4 9.23333 121 2005 28.10

200 62.48 10.4133 136 2261 31.69



Storage Volume provided

Swale 1* Swale 2* Swale 3 Swale 4 Swale 5 Swale 6 Swale 7 Swale 8 Swale 9 Swale 10 Swale 11 Swale 12

S 0.022 0.050 0.017 0.049 0.016 0.041 0.017 0.042 0.026 0.036 0.036 0.041

Z = m 0.08 0.13 0.15 0.08 0.08 0.1 0.1 0.07 0.06 0.08 0.07 0.105

Z1 = 1:X 4 4 4 4 4 4 4 4 4 4 4 4

Z2 = 1:X 4 4 4 4 4 4 4 4 4 4 4 4

B = m 2 2 2 2 2 0.5 2 2 2 2 2 0.5

L = m 45.5 67.9 37.9 32.7 52.8 22.4 79.7 52.5 50.1 100.9 100.9 44.3

Vol of swale (L*B*Z) 7.28 17.654 11.37 5.232 8.448 1.12 15.94 7.35 6.012 16.144 14.126 2.32575


Basins Surface Area Depth Volume

Detention Basin 1 (1:4 side slopes) 567.0 1.5 814.0

Detention Basin 2 (1:4 side slopes) 350.0 1.5 353.0

346.0 1.5 402.0

Soakaways Width Depth L

Soakaway 1 8.0 Length 16.7

Soakaway 2 5.5 2.0 16.5

total storage provided by swales 113.0 2.0 792.5 -1471.8

storage provided by basin 1 (area *depth) 814.0 5.0 1016.8 -1247.5



storage provided by soakaway 1 (L*B*H) 400.8 50.0 1718.9 -545.4

storage provided by soakaway 2 (L*B*H) 181.5 100.0 2004.7 -259.6

Total storage provided 2264.3 200.0 2260.9 -3.4

Volume to be

stored(m3)

Volume not

accounted

Infrastructure provides suitable storage up to 1:200 year event, elimainating flood risk posed by development due to changes in surface water

RP


Technical Note

14

APPENDIX C: SuDS CALCULATIONS

Status of Design DetailDesign Manager / PM James TunnicliffeDesigner James Tunnicliffe

Swale Design 100 Year Capacity

Swale 1* Swale 2* Swale 3 Swale 4 Swale 5 Swale 6 Swale 7 Swale 8 Swale 9 Swale 10 Swale 11 Swale 12S 0.022 0.046 0.013 0.055 0.015 0.044 0.018 0.067 0.012 0.041 0.023 0.031n 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.035 0.35 0.35 0.35Z = m 0.21 0.16 0.21 0.1 0.1 0.125 0.12 0.09 1 0.09 0.1 0.13Z1 = 1:X 4 4 4 4 4 4 4 4 1 4 4 4Z2 = 1:X 4 4 4 4 4 4 4 4 1 4 4 4B = m 2 2 2 2 2 0.5 2 2 0.5 2 2 0.5L = m 45.5 58.2 37.9 32.7 52.8 22.4 79.7 29.2 115 75 51.5 44.3Checkdam No Yes No Yes No Yes No Yes NA Yes No NoCalculateP = m 3.732 3.319 3.732 2.825 2.825 1.531 2.990 2.742 3.328 2.742 2.825 1.572T = m 3.68 3.28 3.68 2.8 2.8 1.5 2.96 2.72 2.5 2.72 2.8 1.54A = m^2 0.5964 0.4224 0.5964 0.24 0.24 0.125 0.2976 0.2124 1.5 0.2124 0.24 0.1326R = m 0.160 0.127 0.160 0.085 0.085 0.082 0.100 0.077 0.451 0.077 0.085 0.084V = m/s 0.124 0.155 0.094 0.130 0.068 0.113 0.082 0.134 1.840 0.105 0.084 0.097T = min 6.102 6.257 6.688 4.208 13.012 3.310 16.133 3.621 1.042 11.891 10.249 7.631Qdesign = m^3/s 0.074 0.065 0.056 0.031 0.016 0.014 0.025 0.029 2.760 0.022 0.020 0.013Qdesign = l/s 74.1 65.5 56.3 31.1 16.2 14.1 24.5 28.5 2759.6 22.3 20.1 12.8Qstorm 69.8 64.1 53.0 26.1 14.9 11.8 20.5 19.1 2710.0 20.1 16.2 12.5

Swale slopes were calculated using the slope of the cycle track in which it is adjacent*Slope approximated based on best estimate of cycle track slope

Qdesign is greater than Qstorm which means the channels can handle the 30 year storm with a maximum water level of ZAll channels will be 300mm deep so there is sufficient space for even larger storm events to be conveyed

Q=(A*(R^2/3)*(S^1/2))/nR=A/PA=(Z/2)*(B+T)T=B+(Z*(Z1+Z2))P=B+Z*((SQRT(1+Z1^2))+(SQRT(1+Z2^2)))V=Q/A

n = 0.35 is the coefficient for depth of water below or equal to the height of the grass

1:100 Capacity EventCarry flow of 1:100 year eventVmax = 1.0m/s

Status of Design DetailDesign Manager / PM James TunnicliffeDesigner James Tunnicliffe

Design 100 YearFlow to PipeKnowns Pipe 1 Pipe 2 Pipe 3 Pipe 4 Pipe 5 Pipe 6 Pipe 7L= m 17.5 14.5 15.6 16.3 41.0 25.0 27.0D= mm (Diameter Inner) 225.0 150.0 225.0 320.0 180.0 225.0 180.0S= slope 0.0 0.0 0.0 0.0 0.0 0.0 0.0

V=m/s 1.3 1.0 1.3 1.2 0.8 1.3 1.3Q= m^3/s 0.1 0.0 0.1 0.1 0.0 0.1 0.0Qdesign1= l/s 52.0 17.8 52.0 92.8 20.3 52.0 28.8

Qstorm l/s 22.2 16.2 46.9 85.7 24.4 46.4 20.1

Qdesign is greater than Qstorm therefore pipe can handle storm flows

Colebrook-White Formula

( )( )

0.50.5

2.52 2 log3.7 2

k = Colebrook-White roughness coefficient, in metresV = velocity, in metres per secondD = circular cross-section pipe, inside diameter, in metresS = slope,

kV gDSD D gDS

næ öç ÷= - +ç ÷è ø

in metres per metreν = kinematic viscosity of water, in square metres per second.