preliminary drainage strategy land off ......accordance with bre 365 should be undertaken to...

PRELIMINARY DRAINAGE STRATEGY LAND OFF LONGSIGHT ROAD, LANGHO, BB6 8BG

REC REFERENCE:45444P2R2

REPORT PREPARED FOR: HALLAM LAND MANAGEMENT LIMITED

JUNE 2014

National Consultancy, Locally Delivered

www.recltd.co.uk

http://www.recltd.co.uk/

Preliminary Drainage Strategy June 2014 Land off Longsight Road, Langho 45444p2r2

QUALITY ASSURANCE

Issue/revision Issue 1 Revision 1 Revision 2 Revision 3

Remarks Draft Final Revision 1

Date April 2014 June 2014 June 2014

Prepared by H Rudge BSc (Hons),

MSc

H Rudge BSc (Hons),

MSc

H Rudge BSc (Hons),

MSc

Signature

Checked by C Burrows BSc (Hons)

MSc, CEnv

C Burrows BSc (Hons)

MSc, CEnv

C Burrows BSc (Hons)

MSc, CEnv

Signature

Authorised by R Paul BSc (Hons) FGS R Paul BSc (Hons) FGS R Paul BSc (Hons) FGS

Signature

Project number 45444p2r0 45444p2r1 45444p2r2


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TABLE OF CONTENTS

QUALITY ASSURANCE 2

EXECUTIVE SUMMARY 5

1.0 INTRODUCTION 7

1.1 Background 7 1.2 Proposed Development 7 1.3 Objectives 7 1.4 Sources of Information 7 1.5 Limitations of the Study 8

2.0 SITE SETTING 9

2.1 Site Details 9 2.2 Site Description 9

2.2.1 Current Layout 9 2.2.2 Topography 9 2.2.3 Surrounding Hydrology 9 2.2.4 Existing Drainage Features 9 2.2.5 Ground Conditions 10 2.2.6 Groundwater 10

2.3 Future Site Use 10

3.0 PRELIMINARY SURFACE WATER DRAINAGE STRATEGY 11

3.1 Introduction 11 3.2 Pre- and Post-Development Impermeable Areas 11 3.3 Infiltration Techniques 12 3.4 Discharge to Watercourse 12 3.5 Discharge to Sewer 12 3.6 Consultation with the Regulatory Authorities 12 3.7 Surface Water Storage 13

4.0 PRELIMINARY FOUL WATER DRAINAGE STRATEGY 14

4.1 Introduction 14 4.2 Current Conditions 14

5.0 OTHER CONSIDERATIONS 16

5.1 Availability of land for SuDS 16 5.2 Surface Water Discharge Points 16 5.3 Residual Flood Risk 16

6.0 CONCLUSIONS & RECOMMENDATIONS 17


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APPENDICES

Appendix I Limitations Appendix II Figures

Figure 1 – Site Location Plan & Aerial Photograph Figure 2 – Topographical Survey

Figure 3 – United Utilities plc Sewer Plans Figure 4 – Proposed Site Layout

Appendix III Drainage Calculations Appendix IV Consultation Responses


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EXECUTIVE SUMMARY

Site Address Land off Longsight Road, Langho, Blackburn, BB6 8BG

Grid Reference E370552 N434546

Site Area 5.4 hectares (ha)

Current Site

The site currently comprises agricultural land, the northern section of the site is bound by hedgerows and Longsight Road. Mature trees bound the eastern section of the site with a woodland and residential dwelling to the immediate north west of the site. A wall transects across the southern boundary of the site and beyond this is the railway line. An electricity pole is present in the north west of the site this directs overhead electricity lines across the western section of the site.

Proposed

Development The site is to be developed for residential end-uses. This will comprise circa 132 units with associated car parking facilities, access roads and landscaped areas.

Existing Setting &

Infrastructure

Surrounding Hydrology: The closest watercourse to the site is a drainage ditch that runs adjacent to the site’s eastern boundary. This flows north towards Longsight Road before being culverted and emerging at Northcote Road 100m from the site. There is an un-named culverted watercourse located adjacent to the western boundary of the site and flows north before discharging into Bushburn Brook, 519m north of the site. There is also a second un-named watercourse located 200m west of the subject site. Bushburn Brook discharges into the River Calder, 2.14km from the site. Geology: The site is underlain by Devensian Till over bedrock of the Bowland Shale Formation. Infiltration: The National Soil Resources Institute (NSRI) indicates that the site is underlain by slowly permeable seasonally wet clayey soils with impeded drainage characteristics and as such percolation testing in accordance with the requirements of BRE Digest 365 should be undertaken throughout the development site. Groundwater: The Environment Agency Groundwater Source Protection Zones map shows that the site is not located within a groundwater source protection zone. The Groundwater Vulnerability Zones Map shows that the site is underlain by a minor aquifer. Topography: The site slopes from south to north with elevation differences of circa 15m. Land elevations in the south are approximately 94.30AOD sloping to approximately 79.50AOD in the north. Within the northern sector of the site, there appears to be a topographic depression with land subsequently sloping to the north east identified at 76.21mAOD. A topographic high point at the site has been identified at 94.34mAOD within the south of the site. Existing Drainage: There is currently no positive surface water drainage on site and it is assumed that surface water infiltrates to the ground or naturally drains into the watercourse along the eastern and western boundaries. Based on the contour levels shown on the Topographical Survey it is assumed that the majority (approximately 70%) of the site drains towards to watercourse along the western boundary. The sewer plans shows that there is a 300mmØ combined sewer crossing through the southern extent of the site flowing in a north-easterly direction.


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Storm Water

Drainage

Surface water runoff and domestic foul flows should be collected and disposed of via separate drainage systems, in accordance with standard industry practice. In accordance with Sewers for Adoption 7th Edition, pipework should be designed to cater for the 1 in 30 year critical event; with flows retained within the pipes and manholes during the 1 in 1 year event; surcharging allowed during the 1 in 30 year event with no surface flooding; and some surface flooding allowed during the 1 in 100 year event. This surface flooding must be retained within the site i.e. not allowed to migrate beyond the site boundary and must not cause flooding to properties both on and off-site. The National Soil Resources Institute (NSRI) (www.landis.org.uk/soilscapes) indicates that the site is underlain by slowly permeable seasonally wet clayey soils with impeded drainage characteristics. Therefore soakaways may not be feasible option. Should soakaways be deemed unsuitable, a connection to watercourse should be established. The nearest watercourses are located along the eastern and western boundaries of the site. Surface water discharge to watercourse will need to be restricted to Greenfield run-off rates. The estimated 1 in 1 year Greenfield run-off rate in 36.87 l/s. The estimated 1 in 100 year Greenfield run-off rate is 92.39 l/s. A restricted run-off rate can be achieved by installing a flow control device such as a hydro-brake or an orifice plate. Permeable pavement should be utilised for the private drives and off street parking areas wherever topography within the site permits. Adoption: Surface water drains and sewers serving the estate roads only may be adopted by the local Council.

Foul Water

Drainage

Any foul discharge to public sewer will need to be agreed in principle with United Utilities plc. The foul flows from the development should be discharged into the public foul sewer which crosses across the southern area of the site. Connection points would be agreed with United Utilities plc at the time of making a formal application to connect to the sewers.

Recommendations

Prior to undertaking a detailed drainage design, infiltration testing in accordance with BRE 365 should be undertaken to determine if soakaways are suitable.

Permeable paving should be used where possible.

Foul discharge will need to be agreed in principle with United Utilities plc. Foul sewers will need to be designed in accordance with Sewers for Adoption 7th edition.

A 3m easement will be required on either side of the public combined sewer.

A 15m easement will be required from any dwellings and the required Sewage Pumping Station.

Land Drainage Consent is required from Lancashire County Council’s Flood Risk Management prior to any discharge to watercourse.


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1.0 INTRODUCTION 1.1 Background Resource and Environmental Consultants Ltd (REC) have been commissioned by Hallam Land Management Ltd to undertake a Preliminary Drainage Strategy and Foul Water Management Plan for a proposed residential development of land at Longsight Road, Langho. 1.2 Proposed Development A Proposed Site Layout has been provided to REC Ltd and it is understood that the site is to be developed for residential end-uses. This will comprise circa 132 units with associated car parking facilities, access roads and landscaped areas. The Proposed Site Layout is provided in Figure 4 in Appendix II. 1.3 Objectives The National Planning Policy Framework (NPPF) and Environment Agency Guidance Note 1 (April 2012) requires an assessment of surface water management for development proposals within Flood Zone 1 i.e. with a low risk from fluvial flooding; which are in excess of 1 Hectare in size. The NPPF states that surface water arising from a developed site should, as far as practicable, be managed in a sustainable manner to mimic the surface water flows arising from the site prior to the proposed development, while reducing the flood risk to the site itself and elsewhere, taking climate change into account. The objectives of the preliminary drainage strategy are to:

Assess the existing hydrological conditions of the site from desktop investigation, site investigations and consultations as appropriate;

Undertake a review of the public drainage system infrastructure and capabilities within a suitable distance of the site;

Review current development proposals and methods for disposal of domestic foul and surface water runoff, as appropriate, in accordance with standard industry practice;

Undertake an initial assessment of the surface water drainage options and identify elements that will require further investigation e.g. percolation testing; and,

Undertake an initial assessment of the domestic foul flow drainage options and identify elements that will require further investigation.

1.4 Sources of Information Background information was sought from the following sources:

Environment Agency Indicative Flood Mapping;

United Utilities plc sewer record maps;

The Joint DEFRA/EA Flood and Costal Erosion Risk Management R&D Programme, R&D Technical Report W5-074/A/TR/1 rev. E "Preliminary rainfall runoff management for developments" (2012);

CIRIA Report C697 – The SuDS Manual;


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CIRIA Report X108 – Drainage of Development Sites – A Guide;

CIRIA Report C635 – Designing for Exceedance in Urban Drainage – Good Practice;

CIRIA Report C522 – SuDS Design Manual;

The BRE Digest 365 – Soakaway Design;

Sewers for Adoption 7th Edition;

Building Regulations Approved Document Part H;

The Institute of Hydrology Reports 124 & 126;

The HR Wallingford Sustainable Drainage Guidance and Tools;

Ordnance Survey Landranger;

National Soil Resource Institute; and,

British Geological Survey Solid and Drift Geological. 1.5 Limitations of the Study The limitations of the report are provided within Appendix I.


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2.0 SITE SETTING 2.1 Site Details Site Address Land off Longsight Road, Langho, Blackburn, BB6 8BG

National Grid Reference E370552 N434546

Site Area 5.4ha

2.2 Site Description 2.2.1 Current Layout The site currently comprises agricultural land, the northern section of the site is bound by hedgerows and Longsight Road. Mature trees bound the eastern section of the site with a woodland and residential dwelling to the immediate north west of the site. A wall transects across the southern boundary of the site and beyond this is the railway line. An electricity pole is present in the north west of the site this directs overhead electricity lines across the western section of the site. A Site Location Plan is presented as Figure 1 in Appendix II. 2.2.2 Topography A topographic survey of the site indicates that the site slopes from south to north with elevation differences of circa 15m. Land elevations in the south are approximately 94.30AOD sloping to approximately 79.50AOD in the north. Within the northern sector of the site, there appears to be a topographic depression with land subsequently sloping to the north east identified at 76.21mAOD. A topographic high point at the site has been identified at 94.34mAOD within the south of the site. The Topographical Survey of the site is presented as Figure 2 in Appendix II. 2.2.3 Surrounding Hydrology The closest watercourse to the site is a drainage ditch that runs adjacent to the site’s eastern boundary. This flows north towards Longsight Road before being culverted and emerging at Northcote Road 100m from the site. There is an un-named culverted watercourse located adjacent to the western boundary of the site and flows north before discharging into Bushburn Brook, 519m north of the site. There is also a second un-named watercourse located 200m west of the subject site. Bushburn Brook discharges into the River Calder, 2.14km from the site. There are a series of drainage ditches associated with the fields beyond the A586 to the east and southeast between 100m and 500m from the site and varying in size depending on the characteristics of the field they drain. A series of ponds are located within the vicinity of the site varying between 444m to 673m the east and southwest. 2.2.4 Existing Drainage Features There is currently no positive surface water drainage on site and it is assumed that surface water infiltrates to the ground or naturally drains into the watercourse along the eastern and


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western boundaries. Based on the contour levels shown on the Topographical Survey it is assumed that the majority (approximately 70%) of the site drains towards to watercourse along the western boundary. United Utilities plc sewer plans are presented as Figure 3 in Appendix II. The sewer plans shows that there is a 300mmØ combined sewer crossing through the southern extent of the site flowing in a north-easterly direction. 2.2.5 Ground Conditions The BGS geological map shows the following formations are present beneath the site:

Geological Unit

Classification Description Aquifer Classification

Drift Devensian Till Diamicton Unproductive

Solid Bowland Shale Formation Mudstone Secondary (undifferentiated) The National Soil Resources Institute (NSRI) (www.landis.org.uk/soilscapes) indicates that the site is underlain by slowly permeable seasonally wet clayey soils with impeded drainage characteristics. 2.2.6 Groundwater The Environment Agency Groundwater Source Protection Zones map shows that the site is not located within a groundwater source protection zone. The Groundwater Vulnerability Zones Map shows that the site is underlain by a minor aquifer. The vulnerability of the site to groundwater is considered to be low. 2.3 Future Site Use A Proposed Site Layout has been provided to REC Ltd and it is understood that the site is to be developed for residential end-uses. This will comprise circa 132 units with associated car parking facilities, access roads and landscaped areas. The Proposed Site Layout is provided in Figure 4 in Appendix II.


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3.0 PRELIMINARY SURFACE WATER DRAINAGE STRATEGY 3.1 Introduction The Preliminary Surface Water Drainage Strategy has been developed to assess the viability of effectively draining the proposed development. The strategy is designed to provide a sustainable approach and will be supplemented with a preliminary design which will serve as a base for any future design works required to facilitate construction. Foul and surface water drainage systems will be separate in accordance with standard industry practice. Building Regulations Approved Document H provides a hierarchy for disposal of surface water from new development, as follows in order of preference:

Infiltration;

Watercourse; and,

Sewer.

3.2 Pre- and Post-Development Impermeable Areas The proposed development will increase the surface water run-off rates and volumes through the introduction of impermeable areas such as buildings, roads and driveways. Based on the Proposed Site Layout (Figure 4 Appendix II) approximately 39% (2.1 ha) of the 5.4 ha site with be impermeable. .

The pre- and post-development surface water run-off rates and volumes have been estimated in accordance with current best practice with the full calculations presented in Appendix III. A summary of run-off rates and volumes are provided within Tables 3.1 and 3.2 respectively. The additional surface water run-off resulting from a 30% increase for climate change has been taken into account in the post-development calculation only. The pre-development site has been assumed as Greenfield for the purpose of these calculations. Table 3.1 Pre- and post- development run-off rates

Peak Flow (l/s) 1 year 30 year 100 year

Pre-development Peak Flow 36.87 75.07 92.39

Post-development Peak Flow 249.04 609.86 767.02

Increase 212.17 534.79 674.63 Table 3.2 Pre- and post- development run-off volumes

Peak Flow (m3) 100 year

Pre-development Peak Flow 1996.17

Post-development Peak Flow 3463.93

Increase 1467.76 As indicated above, the peak rate and volume of run-off increase as a result of the development. In order to ensure that the increase in surface water run-off will not have an impact elsewhere, the run-off should be dealt with using appropriate Sustainable Urban Drainage techniques (SuDS) to reduce the peak run-off rate to pre-development (Greenfield)


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levels. 3.3 Infiltration Techniques The National Soil Resources Institute (NSRI) (www.landis.org.uk/soilscapes) indicates that the site is underlain by slowly permeable seasonally wet loamy soils with impeded drainage characteristics. Therefore soakaways may not be a feasible option. It is recommended that infiltration tests in accordance with BRE 365 specifications are carried out to determine the feasibility of soakaways. 3.4 Discharge to Watercourse Should soakaways be deemed unsuitable, a connection to watercourse should be established. The nearest watercourses to the site are located along the eastern and western boundaries of the site. The majority of run-off from the site currently drains towards the watercourse on the western site boundary. Surface water discharge to watercourse will need to be restricted to Greenfield run-off rates. The estimated 1 in 1 year Greenfield run-off rate is 36.87 l/s. The estimated 1 in 100 year Greenfield run-off rate is 92.39 l/s. A restricted run-off rate can be achieved by installing a flow control device such as a hydro-brake or an orifice plate. The Environment Agency were contacted (EA ref. NTH2559AB) in order to gain any further information regarding discharge of surface water to the water courses located along the eastern and western boundaries. The EA state that run-off rates should to limited to existing Greenfield run-off rates if they are to directed to watercourse. Flows up to and including the 100 year storm event should be contained on site without causing flooding to the site or increasing the flood risk off site. Additionally, SuDS need to be considered wherever appropriate and permeable paving for private drives should be specified to capture and retain the first 5mm of rainfall. Land Drainage Consent is required from Lancashire County Council’s Flood Risk Management prior to any discharge to watercourse. 3.5 Discharge to Sewer As discharge to watercourse appears to be a feasible option, a surface water connection to the sewer network is not required. As shown on the United Utilities plc sewer plan (Figure 3 Appendix II) there are no public surface water sewers in this area which could accommodate surface water run-off from the site. A surface water connection to a foul sewer is not permitted. 3.6 Consultation with the Regulatory Authorities Consultation with Lancashire County Council’s SAB team was undertaken to obtain any further considerations which are required within the Preliminary Drainage Strategy. The full consultation response is presented within Appendix IV and further recommendations to be included within the drainage design are summarised below:

Land Drainage Consent (LDC) is required prior to any discharge to watercourse;

An 8m easement is required either side of the watercourses located on-site;

If soakaways are unviable, source control and attenuation solutions should be maximised;


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Any highways which are offered for adoption must be in accordance with the current Estate Roads Specification and does not allow for the deliberate use of permeable paving with adopted areas;

The high groundwater flood risk should be considered; and,

The natural flow pathways as a result of topography should be identified and SuDS features should be built around these natural flowpaths.

The Environment Agency were also contacted who confirmed that:

Run-off rates should to limited to existing Greenfield run-off rates if they are to directed to watercourse;

Flows up to and including the 100 year storm event should be contained on site without causing flooding to the site or increasing the flood risk off site; and

Additionally, SuDS need to be considered wherever appropriate and permeable paving for private drives should be specified to capture and retain the first 5mm of rainfall.

3.7 Surface Water Storage In order to achieve a Greenfield discharge rate of 36.87 l/s attenuation storage will be required. Attenuation storage should be provided in the form of ponds, wetland areas, swales, swale-ponds and/or oversized pipes. As shown on the proposed development plan, ponds and swales are proposed for the development. Both ponds and swales have a ‘good’ water quality treatment rating in accordance with The SuDS Manual (CIRIA C697) therefore, the proposed drainage system will provide an adequate level of treatment for surface water run-off and the proposed development will not cause pollution to the receiving watercourse. Given the high groundwater risk at the site, any ponds would require lining and swales should be designed to utilise the natural flowpaths as a result of the site’s topography. Attenuation storage calculations are included within Appendix III. The attenuation volumes have been calculated for the 1% (1 in 100 year) Annual Exceedance Probability (AEP) storm event including a 30% climate change allowance. An estimated storage volume of 1328m3 will be required for the proposed development. This volume is based on a limited discharge rate of 36.87 l/s and an impermeable area of 30% which accounts for all hard surfaced areas including buildings, roads, driveways and parking areas. The developer should consider the use of permeable paving in order to reduce the required attenuation storage volume. The attenuation storage volumes are provided for indicative purposes only and should be verified when undertaking a detailed drainage design.


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4.0 PRELIMINARY FOUL WATER DRAINAGE STRATEGY 4.1 Introduction The Preliminary Foul Water Drainage Strategy has been undertaken to assess the viability of draining the proposed residential development. Building Regulations Approved Document H provides a hierarchy for disposal of foul water from new development, as follows in order of preference:

Public sewer;

Septic tank; and,

Cesspool.

4.2 Current Conditions Any foul discharge to public sewer will be to be agreed in principle with United Utilities plc. The foul flows from the development should be discharged into the 300mmØ public combined sewer which crosses through the southern extent of the site. In order to establish a connection to this sewer a Sewage Pumping Station (SPS) will be required as the majority of the properties will be located on ground level below the invert level of the combined sewer. The SPS should be located within the topographically lower area of the site (i.e. to the north) and should incorporate a 15m easement from any residential dwellings and the SPS. Should the foul sewer be relocated as part of the development, possible discharge points, including the inclusion of a SPS, will need to be re-evaluated once the relocated route is determined. The Colebrook-White equation was used in order to assess the pipe full capacity of the public sewer network. In the absence of known pipe gradients it has been assumed that the pipes are set at gradient to maintain a self-cleansing capacity. The capacity of these sewers was conservatively calculated to be:

300mmØ combined sewer – pipe full capacity = 76.99 l/s.

These are conservative estimates of the sewer capacity and should be verified with United Utilities plc before a detailed design is undertaken. Depending on the actual slopes the capacity of these pipes could be significantly higher. It is also notable that the sewers are servicing existing residential areas and drainage systems, and as such the full discharge rate to capacity will not be achievable. A 3m easement will be required on either side of the 300mmØ public combined sewer. It is proposed that the combined sewer be relocated to accommodate the proposed site layout which will need to be agreed with United Utilities plc at the detailed application phase. Consultation with United Utilities plc has been undertaken as part of the assessment which states that foul flows will be permitted to drain freely into the combined sewers. If pumping is required, United Utilities plc will need to review this and agree a specific pumping regime with the developer to ensure that the existing system is not suddenly overloaded.


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Connection points would be agreed with United Utilities plc at the time of making a formal application to connect to the sewers.


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5.0 OTHER CONSIDERATIONS Foul sewers will need to be designed in accordance with Sewers for Adoption 7th edition. 5.1 Availability of land for SuDS As shown on the Proposed Site Layout, sufficient land will be made available for SuDS within the public open and landscaped areas. 5.2 Surface Water Discharge Points Surface water run-off from the development should be discharged to the watercourses bordering the site. The majority of run-off should drain into the watercourses at the eastern and western site boundaries in order to replicate the existing situation. A gravity connection could be achieved by locating a discharge point at the northeast corner of the site. The bed level of the watercourse in this location is at approximately 75.5mAOD, a minimum of 3m below site levels. 5.3 Residual Flood Risk Exceedence events of the site sewers in excess of the 1 in 100 year event will be permitted to produce shallow depth flooding within the highways or landscaped areas. Road levels should be designed to ensure the water is contained on site and will eventually drain back into the drainage system. This will ensure no risk to people or property within and beyond the development.


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6.0 CONCLUSIONS & RECOMMENDATIONS Conclusions The report has been prepared to support a planning application and as such it is highlighted that the drainage strategy presented is indicative only at this stage of the project; and the final decisions of the surface and foul water drainage system in relation to infiltration devices, permeable pavements and attenuation structures are to be made during the detailed design stage. Surface water will be discharged into watercourses bordering the site at a minimum discharge rate of 36.87 l/s. Attenuation storage will be provided for the 1 in 100 year plus climate change storm event. Attenuation storage will be provided in the form of ponds, swales and oversized pipes. An approximate storm water attenuation volume of 900m3 will be required. Surface water storage will be dispersed (not within a single drainage feature), run-off volumes for the 1 in 100 year event will be managed on site, run-off rates will not exceed Greenfield rates, drainage infrastructure will be accessible for monitoring and maintenance and exeedance events of the proposed drainage system in excess of the 1 in 100 year event will be managed on site. Foul discharge to public sewer will need to be agreed in principle with United Utilities plc. Foul flows should be directed to the 300mmØ public combined sewer which crosses through the southern extent of the site. A Sewage Pumping Station will be required in order to establish a connection to the sewer. Recommendations

Prior to undertaking a detailed drainage design, infiltration testing in accordance with BRE 365 should be undertaken to determine if soakaways are suitable.

Permeable paving should be used where possible.

Foul discharge will need to be agreed in principle with United Utilities plc. Foul sewers will need to be designed in accordance with Sewers for Adoption 7th edition.

A 3m easement will be required on either side of the public combined sewer.

A 15m easement will be required from any dwellings and the required Sewage Pumping Station.

Land Drainage Consent is required from Lancashire County Council’s Flood Risk Management prior to any discharge to watercourse.

END OF REPORT


APPENDIX I

LIMITATIONS

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1. This report and its findings should be considered in relation to the terms of reference and objectives agreed between REC Ltd and the Client as indicated in Section 1.1.

2. For the work, reliance has been placed on publicly available data obtained from the sources identified. The

information is not necessarily exhaustive and further information relevant to the site may be available from other sources. When using the information it has been assumed it is correct and REC Ltd cannot be held responsible for the scope of work, or any omissions, misrepresentation, errors or inaccuracies with the supplied information. No attempt has been made to verify the information.

3. This report has been produced in accordance with current UK policy and legislative requirements which are

enforced by the local authority and the Environment Agency. 4. During the site walkover reasonable effort has been made to obtain an overview of the site conditions.

However, during the site walkover no attempt has been made to enter areas of the site that are unsafe or present a risk to health and safety, are locked, barricaded, overgrown, or the location of the area has not be made known or accessible.

5. The executive summary, conclusions and recommendations sections of the report provide an overview and

guidance only and should not be specifically relied upon without considering the context of the report in full. 6. REC Ltd cannot be held responsible for any use of the report or its contents for any purpose other than that

for which it was prepared. The copyright in this report and other plans and documents prepared by REC Ltd is owned by them and no such plans or documents may be reproduced, published or adapted without written consent. Complete copies of this may, however, be made and distributed by the client as is expected in dealing with matters related to its commission. Should the client pass copies of the report to other parties for information, the whole report should be copied, but no professional liability or warranties shall be extended to other parties by REC Ltd in this connection without their explicit written agreement there to by REC Ltd.

7. New information, revised practices or changes in legislation may necessitate the re-interpretation of the

report, in whole or in part.


APPENDIX II

FIGURES

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Figure 1 Site Location & Aerial Photograph

Site Location

Map data 2014 Google

UU Maps for Safe Dig

Copyright UU 2012. This plan is based on the Ordnance Survey Map with the sanction of the Controller of H.M. Stationary Office. Crown and United Utilities Water copyrights are reserved. Unauthorised reproduction will infringe these copyrights.

The position of the underground apparatus shown on this plan is approximate only and is given in accordance with the best information currently available. The actual positions may be different from those shown on the plan and private service pipes may be shown by a blue broken line. United Utilities Water will not accept liability for anydamage caused by the actual position being different from those shown.

Date : Scale Approx :02/04/2014 11:43:29 5909.35904999204

Extract from maps of United Utilities' Underground Assets

Centre : 370622X : Y : 434464

SoffitINV

LP

LP

LP

BT

MH

Soffit

MH

MHLP

LP

BTBT

LPSP

SP

TP

MH

SP

BT

SP

BT

LP

LP

SPSP

LP

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Stay

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R10m

R10m5.5

3.5m

3.0m3.5m

2.4x160m VISIBILITY TO TANGENT POINT

2.4x146m VISIBILITY ROUNDABOUT EXIT

PROPOSED SITEACCESS

PROPOSED PEDESTRIANREFUGE/UNCONTROLLEDCROSSING

PROPOSED GHOST ISLAND RIGHTTURN ACCESS ARRANGEMENT IN

ACCORDANCE WITH DMRB TD42/95

PROPOSED 2m FOOTWAY

PROPOSED 2m FOOTWAY

LLOOCCAATTIIOONN PPLLAANN

THIS DRAWING IS COPYRIGHT AND MAY NOT BE REPRODUCED INWHOLE OR PART WITHOUT WRITTEN AUTHORITY.

DO NOT SCALE OFF THIS DRAWING

Drg nr

Drg title

Project

Client

Langho

Hallam Land Management Ltd

DrawnScale 1:1250@A3

Masterplan

- -16.06.14 First Issue

NNOOTTEE::1. Do not scale from this drawing2. All setting out, levels and dimensions to be agreed on site.3. The dimensions of all materials must be checked on site

before being laid out.4. This drawing must be read with the relevant specification

clauses and detail drawings5. Order of construction and setting out to be agreed on site.6. This drawing is copyright protected and may not be

reproduced in whole or part without written authority.7. All Dimensions are in millimetres unless Otherwise Stated

Date 16.6.2014

PL1352.M101

PPllaanniitt -- IIEE LLLLPP

0161 928 9281

18 Bowling Green Lane London EC1R 0B

2 Back Gra�on St Altrincham WA14 1DY020 7253 5678


APPENDIX III

DRAINAGE CALCULATIONS

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APPENDIX IV

CONSULTATION RESPONSES

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Subject: RE: Proposed residen�al development - Longsight Road, Langho

From: "Makea�ng, Laura"

Date: 09/06/2014 09:22

To: "'[email protected]'"

CC: "Lowe, Elizabeth" , "Cowan, Sco/"

, "Welsby, Ian"

Good morning, Thank you for offering Lancashire County Council's SAB team the opportunity to comment onthe drainage proposals for the development on Longsight Road, Langho. Feedback in relation to the preliminary drainage strategy is detailed below:

· Ordinary Watercourses – Land Drainage Consent (LDC) is required from the FloodRisk Management team to discharge into a watercourse.

o See http://www.lancashire.gov.uk/corporate/web/?siteid=6907&pageid=42365 forguidance and application forms relating to LDC

o Should you wish to gain further advice on applying for LDC you should [email protected] or call 01772 537949 to discuss your application.

· Easements – We would require the 8m easements either side of the watercourse asdetailed in the preliminary drainage strategy and in your email below

· Storm Water Drainage – Should soakaways not prove a feasible option owing to soilcharacteristics following infiltration testing, it is advised that source control andattenuation with controlled release measures are maximised.

· Permeable Paving – Any area to be offered for adoption as public highway must be inaccordance with the current Estate Roads Specification which can be found on ourwebsite at: http://www3.lancashire.gov.uk/corporate/atoz/a_to_z/service.asp?u_id=664&tab=20 Any queries over interpretation can be directed to our local officer JasonLancaster: [email protected]

This specification does not allow for the use of deliberately permeable paving withinareas to be adopted. We acknowledge that we may need to be more accommodating ofsuch surface water management techniques in the future, and we have started toconsider the implications for highway use and maintenance of permeable paving andother options, but we do not expect the review to be concluded for some months and wecannot indicate when we might be able to amend the Estate Roads Specification. In theinterim period we will uphold the existing specifications.

· Local Flooding Sources – In preparing the final drainage strategy, flooding shouldalso be considered from surface water, ground water and ordinary watercourses (localsources).

o The risk of surface water flooding on the site is low, and largely occurs along themargins of the watercourses

o Groundwater flood risk is high

· Identification of Existing Flowpaths - It is recommended that the findings of thetopographic survey and surrounding hydrology, as detailed in Section 2.2, are used toidentify existing flowpaths and that the drainage strategy and relevant SuDS measures –i.e. attenuation – are built around these "natural" flowpaths with flows constrained to the

RE:Proposedresidentialdevelopment-LongsightRoad,Langho

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Greenfield discharge rate. I hope that you find these comments constructive. Should you wish to discuss any of the abovefurther, please don’t hesitate to contact me. Kind regards,

Laura MakeatingFlood Risk Officer (SuDS & Planning)Flood Risk ManagementLancashire County CouncilT: 01772 533487W: www.lancashire.gov.uk

From: Lowe, ElizabethSent: 02 June 2014 08:39To: Makeating, LauraSubject: FW: Proposed residential development - Longsight Road, Langho

Laura,

Can we look over this together tomorrow?

Thanks,

Elizabeth

From: Cowan, ScottSent: 29 May 2014 08:51To: Lowe, ElizabethCc: '[email protected]'Subject: FW: Proposed residential development - Longsight Road, Langho

Elizabeth,

As Ribble Valley is your SAB district, can you review the document and get back to Hayley please.

Thanks

Sco� Cowan

Senior Flood Risk Management Engineer

Lancashire County Council

From: Hayley Rudge [mailto:[email protected]]Sent: 21 May 2014 16:03To: Cowan, ScottSubject: Proposed residential development - Longsight Road, Langho

Dear Scott,

Following the pre-application meeting for the proposed residential development located off Longsight

Road, Langho, we have now produced a Preliminary Drainage Strategy for the site. As discussed, the site

proposes to discharge to the watercourses to the east and west at the current 1 in 1 year Greenfield run-off

rates with the inclusion of ponds and swales for attenuation/water quality purposes. My client has asked if

you could provide any preliminary comments regarding the strategy or any further considerations which

may need to be included. I have attached the report for your reference in the event you want to check

some of the details however, this is not a final version and is subject to change.


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Also, the EA maps indicate that there are 2 watercourses in the vicinity of the site; one along the eastern

boundary and one along the western boundary. The watercourses are not EA designated 'main rivers' and

therefore are not the EA's responsibility. As standard, we recommended that a 8m easement is provided

from the top of the river banks to any development however, my client has asked if you can confirm that

you would still require this 8m easement either side of the watercourse.

Please feel free to call if you wish to discuss any of these points.

--Kind regards,

Hayley Rudge BSc (Hons) MSc

Flood Risk Consultant | REC Ltd

T: 0161 868 1300 | M: 07817 032 846

E: [email protected] | W: www.recltd.co.uk

Na�onal Consultancy, Locally Delivered

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