drainage and flood strategy report · 2020. 10. 8. · drainage systems discharging to the water...

1

Proposed New Residential Development

Davidson s Mains, Edinburgh

Drainage and Flood Strategy Report

3rd April 2020 REVISION A

PARTICULARS Project Davidson s Mains Client Santon Group Development Ltd

On the Former Water Treatment Works, Fairmilehead Edinburgh Flats on St James Church Car Park Innerleithen Innerleithen 14 Cross Steet Peebles

Report type Drainage Strategy and FRA Commentary

Purpose of report Planning

Report status Final Revision A

NA Date of inital report 20/03/2020 03/04/2020

Author

Russell Blackhall Director Date 03/04/2020

Checked

Viv McMahon Checking Engineer Date 03/04/2020

Approved for Issue

Paula Ketterer Director Date 03/04/2020

On behalf of ENV Consulting Engineers

Registered Office: 1 Rowan Court, Cavalry Park, Peebles EH45 9BU t: 01721 540 606 e: [email protected] VAT Registration Number 262 6164 09 Company Number SC542738

Table of Contents Executive Summary 4 1.0 Introduction 5

2.0 Existing Site Topography 8 3.0 Flood Risk Assessment 11 4.0 Design Proposals/Criteria/Concept 14 5.0 Proposed Development Surface Water Drainage 17 6.0 Proposed Development Foul Water Drainage 21 7.0 Proposed Development Flood Risk Assessment 22 8.0 Conclusion 23 Table of Figures Figure 1 Aerial View the Site 8 Figure 2 Extract from Table 26.2 SUDS Manual 15 Figure 3 Extract from Table 26.3 SUDS Manual 16 Appendices A Location Plan B Proposed Development Plan C Existing Scottish Water Plant D Flood Maps E Proposed Concept Layout F Area Schedule G Surface Water Storage Calculations H Proposed Schematic Drainage Layout I Study Limitations

4

Executive Summary ENV Consulting Engineers were commissioned by the client, Santon Group Developments to provide a drainage strategy for the proposed residential development at the rear of Tesco Metro at 36 Cramond Road South and associated lands to the south. The report concentrates on surface water issues but briefly discusses matters on foul water to inform the relevant authorities such matters are in hand and are being considered under separate cover. An Initial Level 1 Flood Risk Assessment has also been undertaken. This document provides initial designs which can be developed when detail information is available. However, the design shown clearly illustrates a drainage strategy and management plan can be implemented for the development. Surface Water The site has been appraised in accordance with all relevant standards, key documents being the current SUDS manual, Sewers for Scotland V4 and SEPA regulations. A review on methods applicable was implemented and the Local Authority stance on climate change to 40% has been included in the analysis. The proposal is to connect to the already installed public surface water system. The analysis has shown that with flow control to agreed run-off values treatment and storage is needed to a volume of circa 60m³ and 214m³ respectively. Utilising a pre-cast culvert below the access road and the proposed parking areas, via porous surfaces etc the volume of treatment and storage can be accommodated for the 1 in 200-year event with a combined 1.44 exceedance factor. Foul Water The proposal is to connect to the existing foul water system. An assessment of flows shows a nominal increase to the network and is considered to be viable given the network in place. A PDE application was submitted to Scottish Water circa February 2020 and a response is still awaited. No issues are expected in regard of this aspect. Trade Effluent No trade effluent discharges and hence conditions apply to this development.

5

Flood A Level 1 Flood Risk Assessment was undertaken. The risk assessment shows a slight risk from surface water. Given the proposed improvements to the drainage system this can be accommodated with detail design aspects at a later stage.

1.0 Introduction ENV Consultants were commissioned by the client, to prepare an initial drainage strategy for the proposed residential development at , Edinburgh. This assessment is to support the planning in principle submission and has been designed to incorporate Scottish Water and SEPA guidelines. This process also takes account of the Local Planning policies. This report describes primarily drainage strategy for surface water solutions at the proposed development. Comment is also made on foul water assessment. A range of methods have been used to offer a rational overview at this point. This is subject to detail design. A Level 1 Flood Risk Assessment is included in the following sections. 1.1 Site details

Site Details - Proposed Flatted Residential Development, Location - OS Grid Reference - E 320626, N 675555 OS Ref - NT206 755 Nearest Postcode - EH4 5BZ Local Authority - City of Edinburgh Council Planning Reference - 20/01410/PPP Site Area - Approximately 0.478 Ha overall with 0.45 Ha measured for design purposes (Ref Appendix A and E for details)

Current Usage - Asphalted store car park and redundant car garage Status - Brownfield Access - Access from Main Street Site Layout Drawings - Architect, S/4715/PL-00

6

1.2 Background 1.2.1 Drainage It is accepted that management of surface and foul water discharges from not only new developments, but also retro change projects is controlled by well-defined rules and obligations, notably SUDS. The obligation for SUDS to be delivered within all developments is contained within legislation and national policy. The Scottish Environmental Protection Agency (SEPA) is the statutory agency responsible for

the Water Environment and Water Services (Scotland) Act 2003 (WEWS). Under the Water Environment (Controlled Activities) (Scotland) Regulations 2011 it is a general requirement with two exceptions relating to single dwellings and discharge directly entering coastal waters - for new developments with surface water drainage systems discharging to the water environment that such discharges will pass through SUDS. Therefore, SEPA requires appropriate use of SUDS features in new developments, particularly for controlling the quality and rate of discharge to watercourses. The Controlled Activities Regulations (CAR) also provides regulation under general binding rules (GBRs) 10 and 11 for SUDS (SEPA,2018), to which this development will be applicable. 1.2.2 Flood In Scotland, the requirements for a Flood Risk Assessment are set out in the Scottish Planning Policy use planning in Scotland.

The Flood Risk Management (Scotland) Act 2009 sets in place a statutory framework for delivering a sustainable and risk-based approach to managing flooding it places a duty on Scottish Ministers, Scottish Environment Protection Agency, local authorities, Scottish Water and other responsible authorities to exercise their functions with a view to managing and reducing flood risk and to promote sustainable flood risk management. The main elements of flood risk management relevant to the planning system are assessing flood risks and undertaking structural and non-structural flood management measures.

Section 42 of the Flood Risk Management (Scotland) Act 2009 confirms that planning authorities will require applicants to provide an assessment of flood risk where a development is likely to result in a material increase in the number of buildings at risk of being damaged by flooding.

SEPA publication, Land Use Planning System SEPA Development Plan Guidance Note 2a This document has to be

appraising sites. Bringing on board Local Authority specifics, the City of Edinburgh has published guidance in the form of a Development Control document on Flood Protection 2019. With the normal guidance also applying these documents form the basis for appraisal.

7

1.3 Scope of Works/Brief 1.3.1 Drainage The brief was to appraise historical data and undertake drainage strategy in line with the current planning layouts, sufficient for the purposes of a Planning Application in Principle. In line with CEC guidance, the climate change criteria have been up lifted to 40% design appraisal. The 3 key issues to be addressed for the site: 1. Existing systems and status 2. Initial comments on flood risk and surface water surcharge. This links with FRA section

noted below 3. Overview/generalised proposals generated for foul and surface water to confirm design

principles can be accommodated. 1.3.2 Flood As an initial appraisal the brief was to undertake a Level 1 assessment to review risk and identify key areas for design consideration and/or further investigation. In addition, albeit technically out with the brief, to consider the affects of ground conditions a basic geological search was undertaken. The report is based on layouts contained in the Appendices at the end of this report. Clearly these may develop and change as the design process is progressed. Similarly, if this is the case this report will need updating in-line with any new proposals. The calculations presented at this stage are considered to be representative of the general conditions. 1.3.3 Base Information A general set of location plans are included in Appendix A together with the boundary limits. Appendix B shows the proposed development plan, S/4715/PL-00. 1.4 Study Limitations It should be recognised that this report is prepared within accordance with current recommended practice and existing legislation. It is written in the context of a varied residential development with landscaped areas and associated parking. Should there be any alternative use, it would be wise to consult us further to ensure the continued accuracy of the recommendations advised. These are contained in Appendix I.

8

2.0 Overview on Existing Site Topography and Ground Conditions

2.1 Site Description The undernoted aerial photograph shows the site.

Figure 1 Aerial View of the Overall Site Boundary Diagramatic and NTS

The site is generally level. Ranging from 53m AOD at the access point to 52m on the north boundary.

The general levels of the car park and hard areas are circa 51.7m to 52.3m. Access from Main Street falls into site Heavy vegetation is seen along the existing watercourse/culvert line. The site is substantially covered in bitu-mastic materials, existing buildings and hard

surfaces.

Numerous service and manhole covers seen in carpark area.

Numerous surface water gullies seen in car park

Potentially 2 fuel interceptor features noted in car park area

9

2.1 Ground Conditions Technically not within the brief but has to be considered is it effects drainage criteria a desk study exercise was undertaken. 2.2.1 Overview of British Geological Survey published data A typical urban mix of strata is expected but the past site history could show a vast range of materials. A degree of soil contamination is likely, not uncommon in such scenarios. This can be assessed at a later stage and designs at present should take a view to ensure the possibility is covered under the risk assessment.

Superficials Till, Diamicton, typically sandy, gravelly clay. Devensian age. Made ground is expected across the site as a result of past history. To the south possibility for the interaction of Laucaustrine deposits, softer clays and silts.

Solid The Gullane formation, mainly pale sandstones interbedded with grey to dark grey mudstones and siltstones. Subordinate coal, seatrock, ostracod-limestone/dolomite and sideritic ironstone. Thin marine bands also occur.

Porosity likely to be poor to very poor.

2.2 Existing Drainage Systems This section provides a description on the current and past drainage methodologies. 2.2.1 Historical Past Uses The past history of the site and its surrounds are a mix of commercial, industrial (railway etc) with residential on the periphery. From the topography and from the records seen all run-off would have fallen into the past watercourse (now culverted). Treatment and or flow controls would not have been considered or in place. From before, the underlying soils are generally impermeable, so it is accepted that run off eventually reaches the network surrounding the site. 2.2.2 Overview on Current Usage The design principles for the current use are now completely superseded by the SUDS

as an improvement in terms of treatment on those past years noted above. The current use of the site, notably a car park and small industrial works discharges both surface and foul to the nearby public network. Unlike past years, treatment of run-off was identified albeit in basic form. Features to treat oils, petrol etc, via interceptors were more common and at least two are expected within the current car park area. Attenuation was not considered and full flows would have been expected to outflows.

10

2.2.3 Detailed Assessment of Current System To ascertain the current network situation a desk study and site inspection survey was undertaken. This comprised obtaining published data from Scottish Water and the Local Authority, followed by a CCTV and site inspection exercise. The details of this work are contained in the ENV report on site works dated March 2020 under separate cover. The published Scottish Water data show the site to have a 750 mm diameter surface water culvert and a 300mm diameter foul water sewer within the boundary. These run somewhat sequentially and approximately enter the mid-point of the site from the west, then deviate north to the site boundary. Information from CEC shows the presence of a watercourse (now the SW culvert) and the 300mm foul sewer on the north boundary. These, more building control related records show the Tesco site in particular as well as also identifying private surface water systems from the hard areas of the site discharging into the watercourse. In particular, level information was missing from the data. When comparing the site topographical survey with the records, the number of manhole covers did not match the published information. Hence, a CCTV survey was undertaken in an attempt to coordinate all pieces of information. In summary the exercise did confirm the presence of the main surface and foul lines albeit with some discrepancies in detail/conflicts from the published data. Both lines were seen to be in reasonable condition. These are recorded as MH1A to MH3 (Surface) and MH4 to MH6 on the foul line, reference the site report as above. Of particular note was the unexpected change in cross section and materials of the pipes. The surface sewer between MH1A and MH2 is noted as 650 diameter concrete circular becoming 750mm rectangular downstream of MH2. The foul line is seen as 300mm diameter as per the records but changes material from cast iron at MH5 to clay downstream from this point. In terms of catchment it was confirmed the surface line takes run off from at least 4 connections along its length, two of which would appear in the site boundary, approximately between MH1 and 7m past MH2. No intermediate connections were recorded on the foul line between the manholes surveyed. However, it should be noted a length pipe south west of MH4 could not be accessed and potential exists for connections from the garage property and surrounds. At this point it is assumed the surface pipework is under the jurisdiction of Scottish Water as the watercourse has been completely culverted for some years and it is shown on their asset plans. Scottish Water records are shown in Appendix C. This shows infrastructure in place to service the area in general.

11

3.0 Flood Risk Assessment For the purposes of this Planning Application in principle, a Level 1 study has been instructed. 3.1 Introduction This report provides general indication of the potential flood risk to the site and identify whether there are any flooding or surface water management issues that may warrant further consideration or may affect the feasibility of a development. The purpose of a Level 1 Screening Study is to ascertain all sources of flood risk and whether any further work in the form of a Level 2 Flood Risk Assessment (Scoping Study) or Level 3 Flood Risk Assessment (Detailed Study) is required. It may also confirm that the site is at low risk of flooding from all sources to which no further assessment is required to be undertaken. This section covers an assessment of the site in its current state in respect of flood risk and categorises the issues on a risk-based approach. Comments are made in later sections in respect of the proposed development and on whether Level 2 and or 3 studies are required.

3.2 Background

The Scottish Environment Protection Agency (SEPA) provide indicative flood zone maps which display a broad indication of what the sites risk of flooding are, and from what source. This gives an indication on the likelihood of a Flood Risk Assessment being required to accompany a Planning Application for development. In conjunction with The Scottish Planning Policy (February 2010) sets out a risk framework which refers to the land at the time the planning application is made, or a development plan is prepared.

However, the SEPA publications have limitations and, in addition to SEPA, other sources of information can be reviewed which offer a range of views based on general and measured data. Such sources, such as JBA Flood data base, CEH (centre for Ecology and Hydrology) have been used and are described below.

3.3 Risk Assessment Criteria

The following SEPA based values have been used in this assessment.

Little or No Risk

Annual probability of watercourse, tidal or coastal flooding is less than 0.1% (1 in 1000 years)

No constraints due to watercourse, tidal or coastal flooding.

Low to Medium Risk Area

Annual probability of watercourse, tidal or coastal flooding in the range 0.1% - 0.5% (1 in 1000 years to 1 in 200 years)

A Flood Risk Assessment may be required at the upper end of the probability range (i.e. close to 0.5%) or where the nature of the development or local circumstances indicate heightened risk.

Water resistant materials and construction may be required depending on the Flood Risk Assessment.

12

Medium to High Risk

Annual probability of watercourse, tidal or coastal flooding greater than 0.5% (1 in 200 years).

If development is permitted, appropriate measures to manage flood risk will be required and the loss of flood storage capacity mitigated to produce a neutral or better outcome.

Within built up areas, such as towns, villages, employment areas and industrial areas, medium to high risk areas may be suitable for residential, institutional, commercial and industrial development provided flood prevention measures to the appropriate standard already exist, are under construction or are planned as part of a long term development strategy. Water resistant materials and construction should be used where appropriate.

3.4 Assessment After an initial appraisal of the site, and in line with the PPP application, it was considered appropriate that a Level 1 FRA would be suitable in the first instance. This report has been structured in accordance with the accepted, current guidelines above and is submitted as a supporting document for this application.

The following information was reviewed.

SEPA Flood Maps scale 1/10000

CEH (Centre for Ecology and Hydrology) scale 1/10000

JBA Consulting Engineers scale 1/10000

BGS (British Geological Survey) scale 1/50000

Discussions with residents local to the site were informally carried out as well as information requested from SEPA and Scottish Water on flood events.

Anecdotal information to date suggested no major issues.

The following table lists the risk category for the various sources.

Type of Event

Source River Surface Coastal Groundwater Canal

SEPA No risk Low to medium No risk NA NA

CEH No risk No risk No risk NA NA

JBA 1in 75 No risk Low No risk NA No risk

JBA 1in 100 No risk Low No risk NA No risk

JBA 1 in 200 No risk Low No risk NA No risk

BGS No risk No risk No risk Identified NA

In terms of accuracy of information all publications are based on approximations but SEPA in

The flood maps are designed to help you understand how you could be affected by flooding. The maps show you areas which are likely to flood from rivers, the sea

13

and surface water. They don't show flood risk at individual property level. Some consider the JBA models to be more representative.

From the above information the only key risk element arises from surface water to the eastern limits of the site. This is noted as low to medium, circa 0.1m to 0.3m. The source and resultant nature would seem to emanate from the watercourse that runs east to west.

It should be noted that some sources did not record a risk at all to the site.

As noted before this watercourse/culvert current picks up all the run-off from the current carpark and surrounding site/properties. No flow controls or maintenance is evident on the system at present and hence it is considered the models are picking up flows that could be intercepted.

14

4.0 Design Proposals/Criteria/Concept To illustrate the concept of the proposed design Appendix E contains an overview drawing. It should also be highlighted that local diversions of existing pipework are needed. This is shown on Appendix H. The design proposed takes cognisance of possible contamination on the site by virtue of no infiltration systems being proposed. 4.1 Surface Water For surface water design we already know that SUDS methods are needed of which there is a variety of options. For sites of this nature permeable paving is a strong contender. It also provides treatment. However, the site layout dictates constraints and it is considered that the system will comprise a mix of the following possible features.

Permeable paving within parking zones with lined tanks. Filter trenches with impermeable liners. Proprietary filter channels and gully pots Volume storage via tanks or oversized pipework

The former three methods also offer a treatment level. Mass attenuation will be needed. The proposal is to use the above features together with the implementation of proprietary storage systems which can be used to supplement volume. A flow control system will be needed at the outfall position. 4.2 Foul Water In terms of foul water, standard connections from the properties to the public sewer would be the base criteria. 4.3 Trade Effluent Trade effluent is not applicable to this development. 4.4 Assessment Criteria In general, the following key documentation apply. 1. CIRIA C753 SUDS Manual 2. SEPA Document WAT-RM-08 Sustainable Urban Drainage Systems 3. Sewers for Scotland 4 published by Scottish Water Guidance requires surface water to be treated prior to discharge to a watercourse. In this instance we are applying the principle of discharge to a surface water sewer/receiving water.

15

As the development proposals are currently at the planning stage, proposed land uses within the site have been defined as access roads, car parking areas and building space/roof areas.

Roofed areas, car parking and access roads are all cla

Each proposed land use has been numerically categorised based on the susceptibility of producing a pollution risk to receiving surface waters (following discharge of surface water run off). To deliver adequate treatment, the selected SUDS components should have a total pollution mitigation index (for each contaminant type) that equals or exceeds the pollution hazard index (for each pollution type).

Where the mitigation index of an individual component is insufficient, two components (or more) in series will be required. In this case, the Total SUDS Pollution Mitigation Index can be calculated by the following equation.

Total SUDs Mitigation Index = mitigation index1 + 0.5 mitigation index2

Where: mitigation index = mitigation index for component n

The assumed land use and associated hazard levels are detailed in Figure 2, below.

Pollution Hazard Level Total Suspended

solids

Metals Hydrocarbons

Residential roofs

Very Low

0.2

0.2

0.05

Non-residential roofs Low 0.3 0.2 0.05 Residential and Non-residential car parking with infrequent change

Low

0.5

0.4

0.4

Commercial yard and delivery areas, non-residential car parking with frequent change (e.g. hospitals, retail), all roads except low traffic roads and trunk roads/motorways1

Medium 0.7 0.6 0.7

Figure 2 Extract from Table 26.2 SUDS manual: Pollution Hazard Levels

16

Indicative SUDS components and associated total mitigation indices are detailed in Table 26.3 SUDS Manual below. The primary design features are selected as shown.

Proposed Land Use Required Level Proposed SuDS Total Suspended Metals Hydro- carbons of Treatment Component Solids (TSS) Residential roofs 1 Permeable Paving 0.7 0.6 0.6 Bioretention System 0.8 0.8 0.8 Swale 0.5 0.6 0.6 Filter Trench 0.4 0.4 0.4 (Min) Total SuDS Pollution Mitigation Index 0.4 0.4 0.4 Permeable Paving 0.7 0.6 0.6 Low traffic access 2 OR Bioretention System 0.8 0.8 0.8 roads Swale 0.5 0.6 0.6 Filter Trench 0.4 0.4 0.4 (Min) Total SuDS Pollution Mitigation Index 0.9 0.8 0.8 Residential and Non and Permeable Paving 0.7 0.6 0.7 residential car parking with 2 OR Bioretention System 0.8 0.8 0.8 infrequent change Swale 0.5 0.6 0.6 Filter Trench 0.4 0.4 0.4 (Min) Total SuDS Pollution Mitigation Index 0.9 0.8 0.9 Commercial yard and Permeable Paving 0.7 0.6 0.7 delivery areas, non-residential Bioretention System 0.8 0.8 0.8 car parking with frequent change 2 OR Swale 0.5 0.6 0.6 (e.g. hospitals, retail), all roads Filter Trench 0.4 0.4 0.4 except low traffic roads and trunk roads/motorways1 (Min) Total SuDS Pollution Mitigation Index NA NA NA

Roofs

Required Total SuDS Pollution Mitigation Index 0.2 0.2 0.05

Provided Total SuDS Pollution Mitigation Index 0.4 0.4 0.4

Typical values OK OK OK

Roads

Required Total SuDS Pollution Mitigation Index 0.5 0.4 0.4

Provided Total SuDS Pollution Mitigation Index 0.9 0.8 0.9

Typical values OK OK OK

Figure 3 Proposed SUDS and Associated Pollution Mitigation Indices

17

5.0 Proposed Development Surface Water Drainage City of Edinburgh Council requires all new developments to comply with The Water Environment (Controlled Activities) (Scotland) Regulations 2011. General Binding Rule 10. These regulations state that constructed sites must be served by a sustainable drainage system. The SUDS system should be designed in accordance with Sewers for Scotland, the SUDS Manual (CIRIA C753), the legislative planning and environmental protection requirements as required by CEC and the SEPA guidelines. Edinburgh Council requires the SUDS design to include consideration of a flow route for 200-year return period plus 40% climate change. CEC have also set greenfield run-off rates at 4.5lts/sec/Ha. Scottish Waters, Sewers for Scotland requires the surface water system to be designed and constructed so that flooding does not occur in any part of the site in a 1-in-30-year return period design storm flood frequency, with a 1-in-200 year overall minimum flood resilience assessment check. From the previous sections, and to achieve the TYPICAL treatment values the following methods to be considered will be a combination of features which will be optimised once detail design proposals are available. Primarily these will be.

Porous paving, stone filled Filter trenches, standard and proprietary Attenuation tanks

The strategy is to target the use of porous paving and filters for the primary SUDS systems. The design comprises porous surfacing (Block or Macadam) within parking bays with the circulation routes normal bitumastic construction. The site is laid to falls such that run-off enters the porous media via roadside side filters. Hence, 2 levels of treatment are created. Roof water will also discharge directly into the filter drains and receive 1 Level of treatment. Ultimately flow control is created at the low point of the site, north west corner before discharge to surface water sewer. At this point volume storage is crput in place below the access road. With the flow control in place this will back up to accommodate the 200 year event. Discharge will be to the existing/diverted surface culvert. A concept layout is shown in Appendix E.

18

5.1 Surface Water Flow Rates A detailed area analysis has been done for the site and this shown in Appendix F. The surface water flow rates are calculated in accordance with BS EN 752:2008, Ciria 753 and in particular the DEFRA and Pre/Post run-off models. In summary the following apply:

Total site area --------------- 4553m² (0.45 Ha) Roof areas ------------------- 1182m² Porous parking bays ------ 574m² Impermeable roadways --- 1069m² Soft landscape areas ----- 1728m² (Percentage of total 38%)

Edinburgh Council require a model based on 1 in 200 year with 40% CC. We have modelled each standard event and undertaken an extrapolation to assess this later value. Design calculations are contained in Appendix G, but in summary green field run off values circa 4.5 lts/sec/Ha. This is considered lowercase at this point and subject to a more rigorous assessment at detailed design stage.

5.2 Treatment and Attenuation Refer to drawing 701 in Appendix H for detailed illustrations on the calculations and design. As noted above the levels of treatment required for the surface water run-off is 1 treatment level for roof runoff and 2 levels of treatment for roads, driveways and carparks. The detailing of the surfacing will have a min 150 mm filter layer sacrificial to the car park structure for SUDS. The storage calculations via the software applications in Appendix F have been assessed using 2 methods within CIRIA 753, the SUDS manual. This shows the following requirement for 1 in 200-year event for 30% Climate Change, but also extrapolated to 40% Climate Change. 5.2.1 Software analysis Pre/Post Discharge Method 1 in 200-year event with 30% CC 223 m³ + Treatment/Interception 39m³ = 262 Total m³ 1 in 200-year event with 40% CC 236 m³ + Treatment/Interception 39m³ = 275 Total m³ Defra Discharge Method 1 in 200-year with 30% CC 174 m³ + Interception/treatment 24 m³ + LTS 37 m³ = 204 m³ 1 in 200-year with 40% CC 192m³ + Interception/treatment 24 m³ + LTS 39 m³ = 255m³ Looking at storage in isolation a figure of about 214m³ is suggested.

19

5.2.2 Baseline Analysis The treatment figures (Vt) quoted above are directly from the software packages. SUDS manual C753 has empirical methods. Using the base formula in C251 Wallingford, method gives Vt = 113m³/Ha = 52m³ (Whole site) and 19 m³ for roads and hard standings. From first principles treatment volumes were taken as the first 15mm of storm. This would yield; Roofs 17m³ Soft areas (70% run-off) 18m³ Roads and hard areas 25m³, there is a view this should be doubled given 2 levels of treatment needed. Total 85m³ Taking a rational view, it is proposed to use the following volumes; 5.2.3 Summary Treatment Average of derived from 63m³ +52m³+85m³+39m³ = say 60m³ split in proportion to areas Roofs 26% site area Vt = 16m³ Soft areas 38% site area Vt = 23m³ Roads and Car Parks 36% site area Vt = 22m³ Summary Storage for 1 in 200 Year Event An overall attenuation vol of 214m³ is proposed. This takes into account the above criteria and especially the 40% CC noted by the Local Authority. Hence from the layout and areas shown the available features are described in section 5.2.1 etc. Overall storage plus treatment volume is taken at 274m³

20

5.3 System Design An initial design has been calculated and presented. However, as the project progresses features my change and hence the design may need alteration. Nonetheless the information shown is deemed to cover a number of scenarios, including dealing with possible contamination as no infiltration is assumed possible. 5.3.1 Treatment Design For roads and car parks the proposal is to use the upper layers of porous car parking for Level 1 treatment of roads etc and the lower levels for secondary treatment. Level 1 treatment volume provided is 24 m³ Vs a requirement of 22m³ Level 2 treatment volume provided is 74 m³ Vs a requirement of 22m³ Treatment of roof and soft areas only require 1 level and it is proposed to use standalone filter trenches. Level 1 treatment volume provided is 55 m³ Vs a requirement of 39m³ Total treatment available is 153 m³ Vs requirement of 83 m³. This gives an exceedance/factor of safety of 1.83. Note the supplementary volume left is utilised for storage, see sections below. In addition, the hydro filter trench proposed down the kerb also offers potential for treatment. However, given this is an indicative design and details may change, this has not been included at this point. However, it demonstrates there are options still available for optimisation. 5.3.2 Attenuation Design For overall storage requirements a net 214m³ is needed. The proposal is to use remaining filter storage with on-line mass tank storage. Flow control is needed and this will primarily be a hydro-brake on the main line set to the agreed limit of circa 4.5lts/sec. Where offline storage is used orifice plate manholes will be implemented at the end of the line. Volume below porous surfacing and stone tanks (30% Voids) provided 80 m³ Volume within new precast culvert provided 197 m³. Total treatment available is 277 m³ Vs requirement of 214 m³. This gives an exceedance/factor of safety of 1.29. 5.3.3 Summary on SUDS Hence it is considered that surface water controls are achievable.

21

6.0 Proposed Development Foul Water Drainage Again, foul water systems will be designed in accordance with Sewers for Scotland and all relevant codes of practise and falls under the jurisdiction of Scottish Water. A schematic layout is shown in Appendix H.

6.1 Proposed Foul Flow Rates Flow rates have been provided to Scottish Water and a PDE application submitted. The site is currently serviced via a 300mm cast iron. At a conservative grade of 1 in 200 this pipe can service 70lt/sec.

is 1.95lt/sec, which is only some 2.79% of capacity. This combined with the release of connections/flow from demolished buildings that were already connected suggest no issues with foul capacity.

6.2 Trade Effluent No trade effluent will be generated from the proposed development.

22

7.0 Proposed Development Flood Risk Assessment A Level 1 exercise has been undertaken via published evidence from SEPA etc. The only issue identified was a low to medium risk of surface water within the south to eastern portions.

As noted, the current site is substantially hard cover and the development will be introducing soft landscaping features not currently in place which will assist run-off flows. The application also proposes the introduction of SUDS measures. Hence, significant betterment can be achieved with the additional introduction of treatment/storage systems and flow control via SUDS, as mandatory.

The proposal would also introduce perimeter cut-off drains to intercept and control flows from outside the site. This combined with suitable treatment of the existing pipework will result in the collective such risks can be managed. Therefore, it is concluded that this flood risk can be eliminated and can be accommodated within the design of the site.

23

8.0 Conclusions ENV Consulting Engineers were commissioned by the client to undertake a drainage strategy and base Flood Risk Assessment for the proposed new residential development at Davidson s Mains, Edinburgh. The appraisal has been done utilising various accepted methods to give an overview on the site and to confirm if the site can accommodate the design proposals in principle. This takes on board the need for 40% climate change as noted by Edinburgh Council. In conclusion,four factors have been examined, albeit the key emphasis of this report is gauged around surface water issues, notably.

Surface water Foul water Trade effluent Flood potential

1. A sustainable surface water management system can be implemented, and a schematic is included in Appendix G. This based on a 1 in 200-year event.

a. Surface water from all parts of the sites will be treated via an approved SUDS system with both attenuation and treatment volumes being considered. Calculations to date have shown that implementation of normal features such as filter tanks etc within the proposed development can accommodate both flow criteria. A large diameter PC culvert is proposed for main storage.

b. In summary, the appraisal shows treatment storage of 44m³ is needed, the

design provides 98 m³. In respect of attenuation volume, 214 m³ is needed and 277 m³ is provided.

c. It is noted that a review/negotiation with CEC and Scottish Water on run-off

figures should be undertaken at detailed design stage to optimise flows.

2. Proposed Foul Water discharge is considered nominal and can be accommodated within the existing Scottish Water System.

3. Trade effluent does not apply to this development.

4. Low to medium surface water flood risk is currently noted. With the implementation of a controlled flow system as shown, risk of flood issues are considered to be managed via the site design.

5. The report contains concept drawings of the proposals. The demonstrate the proposals can be accommodated using global criteria. Full detail design is still to be undertaken and as such flexibility is needed as the overall layout may need to be adjusted to optimise the final design. Notwithstanding this point, and the proposed development when in use, the design presented is considered to offer significant benefits to the surrounding network.

24

Appendices

25

Appendix A Location Plan

General Plan

Site Plan

Loc 01

A4

/NRC -- -- s/4715

Site Location Plan

March 20

1:1250

DRIVE

SILVERKNOWES

SILVERK

NOWES

TERRAC

E

THE GREEN

MAIN STREET

CORBIEHILL PLACE

CORBIEHILL CRESCENT

MAIN

ST

RE

ET

TH

E

GR

EE

N

QUALITY STREET LANE

CR

AM

ON

D

RO

AD S

OUT

H

EAST B

ARNTON

GARDEN

S

QU

ALIT

Y

ST

RE

ET

MAIN STREET

CLIENT

JOB

DRAWING

Drawn JOB NO REVDR NODATEChecked Approved

SCALE SHEET SIZE

STATUS

[email protected] 0131 346 1189 Tel 0131 346 1145Edinburgh EHI2 6AH 64 Coltbridge Avenue Waterside Studios EDINBURGH:-

yeomanmcallister0 50 100

accepts no responsibility for any inaccuracy in printing of this drawing by any parties.not be used for any purpose other than that for which it is intended.Yeoman McAllister This drawing and its data are the copyright of Yeoman McAllister Architects and must

[email protected] Tel 07825186637SW19WimbledonLONDON:-

PLANNING

The Santon Group

Proposed Residential Development, Davidson's Mains, Edinburgh

0 5 10 100m20 50

Scale 1:1250

N

26

Appendix B Proposed Development Plan

BL

OC

K B

BL

OC

K A

BL

OC

K C

Existing access route to

be maintained

with creatio

n of new

footpath link

Existing Path Link

OP

EN

SP

AC

E

CO

TT

AG

EF

LA

TS

BIN

S

BIN

S

BIN

S

THE GREEN

THE GREEN

MAIN STREET

MAIN STREET

THE GREEN

CRAMO

ND ROAD SO

UTH

EAST B

AR

NT

ON

GAR

DENS

QUALITY STREET

MAIN STREET

MH

MH

WH

WH

WH

WH

WH

WH

WH

WH

WH

B

B

B

B

B

B

B

B

B

B

B

B

B

B

B

B

B

B

B

B

B

B

B

B

EL

EL

EL

EL

EL

EL

EL

EL

EL

EL

EL

EL

LP

RL

RL

RL

RL

RL

RL

RL

EC

C

C

G

WT

GP

S1

51.6

46

GP

S2

52.1

93

R1

51.5

60

675420N

675440N

675440N

675460N

675460N

675480N

675480N

675500N

675500N

675520N

675520N

675540N

675540N

675560N

675560N

675580N

675580N

675600N

675600N

320560E 320560E

320580E 320580E

320600E 320600E

320620E 320620E

320640E 320640E

320660E 320660E

320680E

320700E

51.7

2 51.7

1

51.6

651.7

5

51.8

7

51.6

8

51.7

1

51.7

3

51.7

6

51.9

9

52.1

8

52.1

2

52.1

5

52.2

0

52.0

0

52.1

2

52.1

2

52.1

8

52.1

9

52.2

9

52.5

5

51.97

51.95

51.93

51.96

51.93

51.83

51.81

51.7

1

51.4

3

51.8

5

51.8

2

51.6

2

51.8

8

51.8

051.7

5

51.8

1

51.9

4

51.8

7

51.8

5

51.9

3

51.8

5

51.7

8

53.3

9

53.4

3

53.4

1

53.4

0

51.2

8

51.8

9

51.4

6

53.5

9

52.7

5

52.5

4

52.3

7

51.8

2

51.2

1

53

.12

53.2

0

53.0

252.9

6

53.0

6

53.2

3

53.1

853.2

2

53.3

0

53.2

653.2

053.1

253.0

1

53.0

353.1

9

53

.17

53

.16

53

.09

53

.09

53.2

6

53.1

8

53.2

453.2

1

52.8

3

52.6

0

52.6

0

52.3

7

52.1

2

57.3

3

57.3

8

56.5

1

59.3

6

58.7

3

60.6

0

61.3

162.6

5

58.9

6

52.6

052.5

4 52.5

4

52.3

7

55.6

3

57.4

0

53.7

7

54.6

5

56.1

5

55.8

2

59.0

9

59.9

1

57.8

2

52.9

5

52.9

5

51.4

3

59.2

5

53.3

7

52.8

6

52.6

1

52.3

6

57.0

0

52.5

5

52.3

2

52.0

3

51.8

1

51.4

2

51.1

7

51.5

7

51.5

2

51.5

2

FO

OT

PA

TH

(AS

PH

AL

T)

ST

ON

E W

AL

LS

TO

NE

WA

LL

ST

EP

S

TIMBER DECKING

STEP

BRICK WALL

BRICK WALL

DENSE

FOLIA

GE

WIR

E M

ESH F

ENCE

WIRE MESH FENCE

WIRE MESH FENCE

HOUSE

HOUSE

HO

USE

HOUSE

PUBLIC HOUSE

FL

AT

S

BUIL

DIN

G

GA

RD

EN

PR

IVA

TE

GA

RD

EN

(NO

AC

CE

SS

)

ASPHALT

ASPHALT

STONE WALL

GR

ASS

CO

NCRETE W

ALL

FO

OTPATH (A

SPH

ALT)

BRIC

K W

ALL

BRIC

K W

ALL

WIRE MESH FENCE

WIR

E M

ESH F

ENCE

WIR

E M

ESH F

ENCE

WIR

E M

ESH F

ENCE

TESCO STORE

CAR P

AR

K

(ASPH

ALT)

M A I N S

T R E E T

LINE OF OVERHEAD WIRES

LINE OF OVERHEAD WIRES

LIN

E O

F O

VER

HEAD WIR

ES

OVERGROWN

PR

IVA

TE

GA

RD

EN

S

PR

IVA

TE

GA

RD

EN

S

CO

NCRETE K

ERB

GR

ASS

A2

1:500

/G

W--

--s/4715

PL

-00

Site L

ayout Plan

Jan '20

CL

IEN

T

JOB

DR

AW

ING

Draw

nJO

B N

OREV

DR N

ODATE

Checked

Approved

SCALESH

EET SIZE

ST

AT

US

info@ym

-architects.comF

ax 0131 346 1189 Tel 0131 346 1145E

dinburgh EH

I2 6AH

64 C

oltbridge Avenue

Waterside Studios

EDINBURGH:-

yeo

manm

callister0

50

10

0

accep

ts n

o re

sp

on

sib

ility fo

r an

y in

accu

racy

in p

rintin

g o

f this

dra

win

g b

y a

ny

partie

s.

no

t be u

sed fo

r an

y p

urp

ose o

ther th

an th

at fo

r whic

h it is

inte

nd

ed.Y

eo

man M

cA

lliste

r T

his

dra

win

g a

nd its

data

are

the c

opyrig

ht o

f Yeom

an M

cA

lliste

r Arc

hite

cts

and m

ust

info@ym

-london.com T

el 07825186637SW

19W

imbledon

LON

DO

N:-

PL

AN

NIN

G

Proposed Residential D

evelopment, D

avidson's Mains, E

dinburgh

The S

anton Group

Locatio

n o

f any N

ew T

rees

KE

Y:

TO

TA

L S

ITE

AR

EA

4475sqm

Indicative Location of E

xisting Trees

Site B

oundary

01

51

020m

Scale 1

:50

0

30m40m

50m

N

RE

VIS

ION

S

DA

TE

DR

AW

ND

ES

CR

IPT

ION

CH

EC

KA

PP

' DR

EV

27

Appendix C Existing Scottish Water Plant

28

Appendix D Flood Maps

Order D

etails

Site Details

Site at 320630, 675560

Order Num

ber:Custom

er Ref:National G

rid Reference:Slice:Site Area (Ha):Search Buffer (m

):

237547716_1_1Davidsons |M

ains320590, 675550A6.751000

Tel:Fax:W

eb:

0844 844 99520844 844 9951www.envirocheck.co.ukPage 1 of 4

A Landmark Inform

ation Group Service v15.0 06-M

ar-2020

BG

S Flood Data M

ap - Slice A

BG

S Flood Data (1:50,000)

Order D

etails

Site Details

Site at 320630, 675560

Order Num

ber:Custom

er Ref:National G


):


ains320590, 675550A6.751000

Tel:Fax:W

eb:


A Landmark Inform


ar-2020

BG

S Flood Data M

ap - Slice A

BG

S Flood Data (1:50,000)

Order D

etails

Site Details

Site at 320630, 675560

Order Num

ber:Custom

er Ref:National G


):


ains320590, 675550A6.751000

Tel:Fax:W

eb:


A Landmark Inform


ar-2020

GeoSm

art Information G

roundwater Flood M

ap -Slice A

GeoSm

art Information G

roundwater Flood M

ap (1:50,000)

Order D

etails

Site Details

Site at 320630, 675560

Order Num

ber:Custom

er Ref:National G


):


ains320590, 675550A6.751000

Tel:Fax:W

eb:


A Landmark Inform


ar-2020

EA/NR

W R

oFRS D

ata Map - Slice A

EA/NR

W R

oFRS D

ata (1:50,000)

Order D

etails

Site Details

Site at 320630, 675560

Order N

umber:

Custom

er Ref:

National G

rid Reference:

Slice:

Site A

rea (Ha):

Search B

uffer (m):

237547716_1_1D

avidsons |Mains

320590, 675550A6.751000

Tel:Fax:W

eb:

0844 844 99520844 844 9951w

ww

.envirocheck.co.uk

Page 1 of 7

A Landm

ark Information G

roup Service v50.0 06-M

ar-2020

CEH

Flood Data M

ap - Slice A

CEH

Flood Data M

ap (1:10,000)

Order D

etails

Site Details

Site at 320630, 675560

Order N

umber:

Custom

er Ref:

National G

rid Reference:

Slice:

Site A

rea (Ha):

Search B

uffer (m):

237547716_1_1D

avidsons |Mains

320590, 675550A6.751000

Tel:Fax:W

eb:

0844 844 99520844 844 9951w

ww

.envirocheck.co.uk

Page 2 of 7

A Landm

ark Information G


ar-2020

JBA 75 Year R

eturn Flood Map (U

ndefended) - Slice A

JBA 75 Year R

eturn Flood Map (U

ndefended) (1:10,000)

Order D

etails

Site Details

Site at 320630, 675560

Order N

umber:

Custom

er Ref:

National G

rid Reference:

Slice:

Site A

rea (Ha):

Search B

uffer (m):

237547716_1_1D

avidsons |Mains

320590, 675550A6.751000

Tel:Fax:W

eb:

0844 844 99520844 844 9951w

ww

.envirocheck.co.uk

Page 3 of 7

A Landm

ark Information G


ar-2020

JBA 100 Year R

eturn Flood Map (U


JBA 100 Year R

eturn Flood Map (U


Order D

etails

Site Details

Site at 320630, 675560

Order N

umber:

Custom

er Ref:

National G

rid Reference:

Slice:

Site A

rea (Ha):

Search B

uffer (m):

237547716_1_1D

avidsons |Mains

320590, 675550A6.751000

Tel:Fax:W

eb:

0844 844 99520844 844 9951w

ww

.envirocheck.co.uk

Page 4 of 7

A Landm

ark Information G


ar-2020

JBA 200 Year R

eturn Flood Map (U


JBA 200 Year R

eturn Flood Map (U


Order D

etails

Site Details

Site at 320630, 675560

Order N

umber:

Custom

er Ref:

National G

rid Reference:

Slice:

Site A

rea (Ha):

Search B

uffer (m):

237547716_1_1D

avidsons |Mains

320590, 675550A6.751000

Tel:Fax:W

eb:

0844 844 99520844 844 9951w

ww

.envirocheck.co.uk

Page 5 of 7

A Landm

ark Information G


ar-2020

JBA 1000 Year R

eturn Flood Map (U


JBA 1000 Year R

eturn Flood Map (U


Order D

etails

Site Details

Site at 320630, 675560

Order N

umber:

Custom

er Ref:

National G

rid Reference:

Slice:

Site A

rea (Ha):

Search B

uffer (m):

237547716_1_1D

avidsons |Mains

320590, 675550A6.751000

Tel:Fax:W

eb:

0844 844 99520844 844 9951w

ww

.envirocheck.co.uk

Page 6 of 7

A Landm

ark Information G


ar-2020

JBA C

anal Failure Flood Map - Slice A

JBA C

anal Failure Map (1:10,000)

dumm

y

Order D

etails

Site Details

Site at 320630, 675560

Order N

umber:

Custom

er Ref:

National G

rid Reference:

Slice:

Site A

rea (Ha):

Search B

uffer (m):

237547716_1_1D

avidsons |Mains

320590, 675550A6.751000

Tel:Fax:W

eb:

0844 844 99520844 844 9951w

ww

.envirocheck.co.uk

Page 7 of 7

A Landm

ark Information G


ar-2020

OS W

ater Netw

ork Map - Slice A

OS W

ater Netw

ork Lines Map (1:10,000)

Order Number: 237547716_1_1 Date: 06-Mar-2020 rpr_ec_datasheet v53.0 A Landmark Information Group Service

Flood Screening Report Datasheet

Order Details:Order Number:

Customer Reference:

National Grid Reference:

Slice:

Site Area (Ha):

Search Buffer (m):

Site Details:

Client Details:

237547716_1_1

Davidsons |Mains

320590, 675550

A

6.75

1000

Site at 320630, 675560

Mr R BlackhallEnv Consulting Engineers LtdENV Consultants LtdUnit 1 Rowan CourtCavalry ParkPeeblesPeeblesshireEH45 9BU

Report:®Envirocheck


Summary

EA / NRW / CEH Flood Data

JBA Flood Data

BGS Flood Data

GeoSmart Information Groundwater Flood Data

OS Water Network Data

Report Section and Details Page Number

Contents

-

-

1

21

36

39

The Summary section provides an overview of the data contained within the report, detailing the number of data set features or the existence of a data set in relation to the buffer(s) selected. For ease of reference, the report is broken down into seven sections of data.

This section details data from the Environment Agency/Natural Resources Wales and the Centre for Ecology and Hydrology.

The EA/NRW data is reported to a distance of 250m from the edge of the site polygon and details both Zone 2 (extreme) andZone 3 flood extents, as well as flood defences, flood water storage areas and areas benefiting from flood defences.

The CEH data is reported to a distance of 250m from the edge of the site polygon and covers flood data for Scotland, dividedinto levels based on the frequency and magnitude of a predicted 100 year term.

All data sets within this section are plotted and feature on the EA / NRW / CEH Flood Data (1:10,000) map. For added value,OS Contour data is also plotted, detailing contours, spot heights and land water boundaries.

This section contains the Comprehensive Flood Map ("CFM") data from JBA Risk Management Limited. The data is based upon the likelihood of a flood occurrence for up to 4 flood return periods depending on the type of flooding; these being 75 years, 100 years, 200 years and 1000 years. Each layer being modelled at a 5m cell resolution.

Each return period is depicted on a separate 1:10,000 scale map and reports features to a distance of 250m in the datasheetfrom the edge of the site polygon.

For each return period the following three sources of flooding are identified, surface water or pluvial flooding, undefended river flooding or fluvial flooding and undefended coastal flooding. In each case the extent of the flooding source is displayed with the associated depth range.

In addition, a 1:10,000 scale map depicting flooding from a Canal Failure and a coverage check for this dataset is included.

Where coverage exists, information is reported in the datasheet where the site could be affected by flooding that results froma dam breach.

For added value, OS Contour data is also plotted, detailing contours, spot heights and land water boundaries.

This section contains two BGS data sets; namely Geological Indicators of Flooding and Groundwater Flooding Susceptibility,both of which report features out to a possible 1000m, with coverage in England, Wales and Scotland.

Each data set is plotted on a seperate BGS Flood Data (1:50,000) map.

This section contains data provided by GeoSmart Information who, building on their expertise, have developed algorithms and calibrated predictions of the risk of groundwater flooding occurring in Great Britain. The resulting map, classifies groundwater flood risk for each 5m x 5m into four categories, negligible, low, moderate and high. These classifications are based on the level of risk, combining severity and uncertainty that a site will suffer groundwater flooding within a return periodof about 200 years.

This section details the MasterMap Water Network data sourced from the Ordnance Survey. The OS MasterMap Water Network data details a network representing the watercourse within Great Britain.

The OS Water Network Lines data set details the approximate central alignment of a watercourse, including rivers, lakes andcanals.

The OS Water Network Nodes data set details features that represent a river's source, end, a junction where three of more links meet, and places where the real world related attribution changes; for example a watercourse becoming tidal.

The data sets within this section are plotted and feature on the OS Water Network Map (1:10,000) . For added value, OS Contour data is also plotted, detailing contours, spot heights and land water boundaries.


EA/NRW Historic Flood Events Data

EA/NRW RoFRS Data

Flood Insurance Risk Data

Data Currency

Data Suppliers

Useful Contacts

Contents

Report Version v53.0

-

-

41

42

43

44

This section details Historic Flood data sourced from the Environment Agency/Natural Resources Wales and from data held by Landmark. The EA/NRW Historic Flood Events data is reported to a distance of 1000m from the edge of the site polygon and details recorded historic flood events from 1703 to October 2008. The data also contains information on the source and cause of the flood, and how the flood outline was established.

Also included in this section is Landmark's Historical Flood Liabilities data set, which identifies areas that are liable to flood based on systematic analysis of historical mapping dating back to the mid 19th century.

Both data sets within this section are plotted and feature on the EA/NRW Historical Flood (1:10,000) map. For added value, OS Contour data is also plotted, detailing contours, spot heights and land water boundaries.

This section details the Risk of Flooding from Rivers and Sea (RoFRS) data sourced from the Environment Agency/Natural Resources Wales and is reported to a distance of 1000m from the edge of the site polygon. The RoFRS data provides an indication of areas of land at risk of flooding from rivers and the sea. These areas of land, called impacted cells, are represented as 50 metre squares, or smaller areas where a square is intersected by a river or coastline.

The average height information of the impacted cell, modelled river and sea levels and information about over 200,000 flood defences are used as inputs to a computer flood model run by the Environment Agency/Natural Resources Wales. The model compares the probability that the flood defences will overtop or breach and the distance of the impact cell from the river or the sea for 40 scenarios for probabilities of between 100% to 0.1%.

The results are then consolidated to calculate a single probability category for each impacted cell. These results have been validated by local staff using their local knowledge and expertise. RoFRS is a national flood risk assessment and does not contain information about property thresholds. Due to variations in the input data and the performance of the computer flood model at particular locations, the resulting category of an impacted cell should only be used at a specific study scale. In certain areas it would only be appropriate to compare risks between towns and counties whereas in other areas they would be more suitable for understanding risk at a street level. The level of suitability for a particular cell is indicated by the cell's suitability scale.

The data within this section is plotted and feature on the EA/NRW RoFRS Data (1:50,000) map. This dataset is not available in Scotland.

This section contains flood risk data from Crawford and Company. This dataset is not plotted on any of the associated Flood maps.

Crawford & Co have generated an Insurance Claims rating for Flood Risk. The risk is determined by comparing the number of flood insurance claims made to the number of properties in the postcode sector. The data will also include flood claims from domestic accidents or blocked drains, as well as flooding from river or tidal events. Flood insurance claim ratings are reported for the site only.


Summary

Data Type PageNumber On Site 0 to 250m 251 to 500m

EA / NRW / CEH Flood Data

JBA Flood Data

BGS Flood Data

GeoSmart Information Groundwater Flood

OS Water Network Data

EA/NRW Historic Flood Events Data

EA/NRW RoFRS Data

Flood Insurance Risk Data

501 to 1000m

River Flood Data (Scotland)

JBA 75 Year Return (undefended) - Pluvial

JBA 75 Year Return (undefended) - Fluvial

JBA 75 Year Return (undefended) - Coastal









JBA Canal Failure

JBA Dam Break

BGS Geological Indicators of Flooding

BGS Groundwater Flooding Susceptibility

GeoSmart Information Groundwater Flood Risk

OS Water Network Lines

OS Water Network Nodes

Historic Flood Events

Historical Flood Liabilities

RoFRS - Risk of Flooding from Rivers and Sea

Postcode Sector Flood Insurance Claim Ratings

24

36

38

1

6

5

3

1

2

92

105

133

46

6

2

3

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

2

56

3

1

2

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

n/a

1

216

27

2

3

n/a

pg 1

pg 6

pg 12

pg 21

pg 21

pg 36

pg 39

pg 39

pg 41

Report Version v53.0

Order Number: 237547716_1_1 Date: 06-Mar-2020 rpr_ec_datasheet v53.0 A Landmark Information Group Service Page 1 of 44

JBA Flood Data

MapID Details

QuadrantReference (Compass Direction)

EstimatedDistanceFrom Site

Contact NGR























A13NE(NE)

A13NE(NE)

A13NE(NE)

A13SW(SW)

A13NE(NE)

A13NE(E)

A13NE(E)

A13NE(W)

A13NE(E)

A13NE(E)

A13NE(W)

A13NE(E)

A13NE(E)

A13NE(E)

A13NE(E)

A13NE(E)

A13NE(SW)

A13NE(E)

A13SE(SW)

A13SE(E)

A13SE(E)

A13SE(E)

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Greater than 0.1m and Less than or equal to 0.3m






















320650675640

320635675630

320645675630

320545675460

320655675615

320680675565

320670675550

320585675545

320645675546

320665675546

320575675545

320670675545

320685675545

320690675540

320645675545

320665675545

320590675540

320645675540

320580675535

320690675530

320655675525

320675675525


JBA Flood Data

MapID Details



Contact NGR























A13SE(S)

A13SW(S)

A13SE(S)

A13SE(S)

A13SE(S)

A13SW(S)

A13NE(N)

A13SE(S)

A13SE(S)

A13NE(N)

A13NE(N)

A13NE(N)

A13NE(N)

A13NE(NE)

A13SW(S)

A13SW(S)

A13SW(SW)

A13SE(S)

A13NE(NE)

A13NE(NE)

A13NE(NE)

A13NE(NE)

0

0

8

10

11

12

13

18

21

24

24

27

34

35

36

37

38

40

40

45

51

55

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:























320575675460

320565675455

320585675405

320590675405

320594675405

320570675400

320630675670

320580675395

320620675400

320620675680

320630675680

320640675685

320625675690

320690675700

320530675370

320525675370

320520675370

320590675375

320700675705

320705675710

320695675715

320705675720


JBA Flood Data

MapID Details



Contact NGR























A13NE(NE)

A13SE(S)

A13NE(NE)

A13SW(S)

A13NE(NE)

A13NW(W)

A13NW(W)

A13NW(W)

A13NW(W)

A13SE(S)

A13SE(S)

A13SE(S)

A13SE(S)

A13SE(S)

A13SE(S)

A13SE(S)

A13SW(S)

A13SW(S)

A13SW(S)

A13SW(S)

A13SE(S)

A13SW(S)

59

60

63

66

67

77

81

81

84

98

100

104

105

107

107

114

120

121

124

124

126

127

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:























320710675725

320594675355

320715675730

320540675340

320720675735

320310675610

320305675610

320305675605

320305675620

320670675330

320650675325

320645675320

320655675320

320605675310

320665675320

320650675310

320565675290

320540675285

320560675285

320570675285

320575675285

320545675280


JBA Flood Data

MapID Details



Contact NGR























A13SW(S)

A13SE(S)

A13SW(W)

A13NE(N)

A13SW(S)

A13SW(S)

A13SW(SW)

A13SW(W)

A13SW(SW)

A13SW(W)

A13SW(S)

A13SW(S)

A13SW(W)

A13SW(W)

A13SW(W)

A13SW(W)

A13SW(S)

A13NE(N)

A13SW(W)

A13NE(N)

A13NE(N)

A13SW(SW)

132

136

138

141

142

142

144

145

147

147

151

153

154

157

157

158

160

160

161

161

165

169

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:























320520675275

320575675275

320330675440

320690675805

320545675265

320515675265

320330675430

320310675455

320330675425

320300675465

320540675255

320565675255

320295675460

320295675455

320310675435

320305675440

320570675250

320695675825

320290675455

320690675825

320695675830

320310675415


JBA Flood Data

MapID Details



Contact NGR























A13SW(W)

A13SE(S)

A14SW(SE)

A13NW(NW)

A13NW(NW)

A14SW(SE)

A13NW(NW)

A13NW(NW)

A14SW(SE)

A13NW(NW)

A13NW(NW)

A13NW(NW)

A13SE(S)

A13SE(S)

A13SE(S)

A13SE(S)

A13SE(S)

A14SW(SE)

A13NW(NW)

A8NE(S)

A14SW(SE)

A13NW(NW)

175

177

180

181

181

182

184

184

189

192

206

207

209

210

211

214

216

227

229

231

232

235

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:

Flood Depth:


















Greater than 0.1m and

drainage and flood strategy report · 2020. 10. 8. · drainage systems discharging to the water...

Documents