FRA Report Bacup Revision C - Rossendale Britannia Beck ... 5.4 Preliminary Drainage Strategy 26 ... within the functional floodplain or Zone 2 or 3 of the flood map until the question

Report No.11182/I/01 Revision C Project Details. FRA – Residential Development off New Line, Bacup Date. November 11

Flood Risk Assessment

Paul Waite Associates have been appointed by Harron Homes, to undertake a Flood Risk Assessment in support of a planning application for a residential development on land off New Line in Bacup, Lancashire.

Clients Details Harron Homes Ltd Colton House Temple Point Bullerthorpe Lane Leeds LS15 9JL

Documents Revision Status

ISSUE: DATE COMMENTS

‐ November 10, 2011 FINAL

A November 21, 2011 FINAL – Minor amendments following Client’s comments

B November 22, 2011 FINAL – Minor amendments following Client’s comments

C November 25, 2011 FINAL – Minor amendment to Section 6.0 following

Client’s comments


Contents

Executive Summary 1

1.0 Introduction 3

2.0 Approach to the Flood Risk Assessment 4

2.1 Approach 4

2.2 Application of the Sequential and Exceptions Test 4

3.0 Site Details 6

3.1 Location 6

3.2 Former/Current Use 7

3.3 Proposals 9

3.4 Boundaries 9

3.5 Topography 10

3.6 Existing Drainage 10

3.7 History of Flooding 11

3.7.1 British Hydrological Society – Hydrological Events 11

3.7.2 Internet Search for Historical Flooding 11

3.7.3 Rossendale SFRA 12

3.7.4 Culvert Repair Works at Bacup 13

4.0 Flooding Mechanisms 14

4.1 Britannia Beck 14

4.2 Fluvial – Unnamed Watercourse 15

4.2.1 General 15

4.2.2 Estimation of 1 in 100 year Flow within the Unnamed Watercourse 16

4.2.3 Capacity of the 1600mm Diameter Culverted Watercourse 17

4.2.4 Capacity of the Open Channel Section of Watercourse 18

4.2.5 Capacity of the 1850mm Diameter Culverted Watercourse 21

4.2.6 Blockage 21

4.3 Surface Water Runoff 22


4.3.1 Increased Runoff Due to Development 22

4.4 Overland Flow 23

4.5 Ponding 24

5.0 Material Consideration In Respect of PPS25 25

5.1 Climatic Change 25

5.2 Environment Agency Flood Map 25

5.3 Finished Floor Levels 26

5.3 Emergency Access and Egress during Times of Flood 26

5.4 Preliminary Drainage Strategy 26

5.4.1 Infiltration 26

5.4.2 Discharge to Watercourse 27

5.4.3 Attenuation of Flow 27

5.5 Sustainable Urban Drainage (SUDS) 28

5.5.1 Ponds and Wetlands 29

5.5.2 Green Roof 32

5.5.3 Rainwater Harvesting 32

5.6 Foul Drainage 33

5.7 Maintenance 33

5.8 Easements 33

6.0 Conclusions and Recommendations 34

Tables Table 1 Flood Risk Vulnerability and Flood Zone Compatibility

Table 2 Historical Flood Events

Table 3 Sources of Flooding

Table 4 Indicative Volume of Attenuation

Table 5 SUDs Techniques and Suitability of Use

Report No. 11182/I/01 Revision C Project Details FRA – Residential Development off New Line, Bacup Date. November 11

Figures Figure 1 Location Plan – New Line, Bacup

Figure 2 Historical Map of the Development Site (Circa 1893)



Figure 5 Existing Site Viewed East from the South West Boundary

Figure 6 Open Channel Section of Watercourse to Rear of Existing Residential Properties

Figure 7 Outfall to Britannia Beck

Figure 8 Cross Section Through Open Channel Upstream of Residential Gardens

Figure 9 Photograph Illustrating Watercourse Exiting from Existing Residential Gardens

Figure 10 Environment Agency Flood Map

Appendices Appendix A Existing Site Layout: Topographical Survey

Appendix B Aerial Photographs of the Site (Circa 2000 & 2005)

Appendix C Preliminary Site Layout

Appendix D United Utilities Sewer Record Plans

Appendix E Rossendale SFRA

Appendix F Environment Agency Correspondence

Appendix G IOH124 Calculations

Appendix H Manning’s Equation – Channel Capacity Calculations

Appendix I Colebrook‐White: Culvert Capacity Calculations

Appendix J HY‐8 Culvert Analysis Calculations

Appendix K Indicative Attenuation Volume Calculations

Appendix L SUDs Suitability Matrix

Appendix M Historical Borehole Logs

Appendix N MicroDrainage Calculations

Appendix O Preliminary Drainage Layout


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Executive Summary Paul Waite Associates have been appointed to undertake a Flood Risk Assessment in accordance with PPS25, to support of a planning application for a proposed residential development on land off New Line, in Bacup, Lancashire. The gross development area covers 1.15Ha; and the footprint of the site is shown to lie wholly within Flood Zone 1 of the Environment Agency Flood Map, being the zone comprising land as having less than the 1 in 1,000 annual probability of river or tidal/coastal flooding in any year (<0.1%). The primary flood risk to the site is identified from an unnamed watercourse which traverses the development area; and an increase to surface water runoff and volume from the site. The unnamed watercourse is a small tributary of Britannia Beck; and collects water from the surrounding moorland area via a network of small streams. The watercourse flows generally in a south westerly direction; with flow conveyed via open channel and culverted sections though the site. Using IOH124 for small rural catchments, the 1 in 100 year plus 30% climate change flow is estimated to be 0.807m3/s. The unnamed watercourse enters the development site via a 1.6m diameter culvert along the east boundary. The culvert opens out into an open channel section beneath a decking area within the rear garden area of existing residential properties located along the north boundary of the site. The watercourse exits the residential properties via a rectangular opening in the boundary wall (dimensions 1.45m x 0.75m); prior to entering a 1.85m diameter culverted section, which directs flow across the site to its confluence with Britannia Beck. Calculations indicate that under normal conditions, the open channel and culverted sections of watercourse exhibit sufficient capacity to convey the 1 in 100 year plus 30% climate change flow. In addition, calculations to represent a 50% blockage within the watercourse downstream from the existing residential properties were undertaken; and it was found that the lowest ground level within the existing development is elevated approximately 1 metre; and the ground floor accommodation of the properties situated approximately 4.5 metres above the 1 in 100 year plus 30% climate change flood level. Furthermore, a 50% reduction in cross sectional area within the 1.85m diameter downstream culvert still provides sufficient capacity to convey the 1 in 100 year plus 30% climate change flow within the watercourse.


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It is therefore concluded that the unnamed watercourse presents a low risk of flooding to the proposed development and existing residential properties. Following development it is anticipated that the impermeable area within the site will be increased to 0.52 Hectares; hence there will be a corresponding increase in surface water runoff and volumes leaving the site. The Environment Agency has requested that surface water discharge from the development is restricted to 13l/s/ha, hence a maximum rate of 15l/s over the gross development area. Flows in excess of this will need to be attenuated within the site, prior to discharge into the receiving watercourse. The Environment Agency requires that surface water runoff should be controlled as near to its source as possible, through a sustainable drainage approach to surface water management (SUDs). This approach involves using a range of techniques such as soakaways and swales to reduce flood risk by attenuating the rate and quantity of surface water runoff from a site. Undertaking an assessment of suitable SUDs techniques indicates that there are a number of suitable options available for attenuating surface water from the site. However in accordance with the Environment Agency’s requirements attenuation via wetland storage has been incorporated into the drainage strategy for the development. Calculations indicate that a wetland storage area covering a plan area of 415m3 provides sufficient volume to attenuate flows up to the 1 in 100 year plus 30% climate change event. During this event the maximum depth of water within the wetland area is estimated to be less than 753mm; with flows entering the unnamed watercourse restricted to a maximum rate of 15l/s.


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1.0 Introduction Paul Waite Associates have been appointed to undertake a Flood Risk Assessment in support of a planning application for residential development off New Line in Bacup, Lancashire. The development is shown to be situated wholly within Flood Zone 1 of the Environment Agency Flood Map, being the zone comprising land as having less than the 1 in 1,000 annual probability of river or tidal/coastal flooding in any year (<0.1%). The primary sources of flood risk to the proposed development site have been identified from an unnamed watercourse which traverses the site; along with an increase to surface water runoff from the development site. However other sources of flooding have been considered within this assessment. It is usual for the Environment Agency to raise an objection to development applications within the functional floodplain or Zone 2 or 3 of the flood map until the question of flood risk has been properly evaluated. The Agency will also object to developments where the total site area is in excess of 1 Hectare until suitable consideration has been given to surface water runoff.


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2.0 Approach to the Flood Risk Assessment

2.1 Approach A topographical survey of the existing site was undertaken by Haycock and Todd in September 2011, and is calibrated Ordnance Survey Grid and Datum using GPS. Therefore the resulting site levels have been used within this report. The requirements for flood risk assessments are generally as set out in Annex E of PPS25. The detail and complexity of the study required should be appropriate to the scale and potential impact of the development. For the purposes of this study, the following have been considered:‐

Available information on historical flooding in the area.

Site level information.

Details of structures, which may influence hydraulics of the watercourse and consideration of the effect of blockage of structures.

Estimates of design levels, equivalent to a 200‐year (coastal/tidal) and a 100‐year (fluvial) return period flood event.

Allowances for increased flows resulting from the effects of climate change.

Allowances for sea level rise resulting from the effects of climate change.

Assess the existing runoff characteristics and the potential impact the proposed development will have on the runoff.

Further guidance is also provided in the CIRIA Research Project 624 “Development and Flood Risk: Guidance for the Construction Industry”.

2.2 Application of the Sequential and Exceptions Test

The risk based sequential test should be applied at all stages of planning. Its aim is to steer new development to areas at the lowest probability of flooding, within zone 1. The flood zones are the starting point for the sequential approach. The development is shown to be situated wholly within Flood Zone 1 of the Environment Agency Flood Map, being the zone comprising land as having less than the 1 in 1,000 annual probability of river or tidal/coastal flooding in any year (<0.1%). Proposals for the site incorporate residential development, and as such Table D2 of Annex D within PPS25 indicates that the development is classified as ‘more vulnerable’.


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Table 1: Flood Risk Vulnerability and Flood Zone ‘Compatibility’

Flood Risk Vulnerability Classification

Essential Infrastructure

Water compatible

Highly Vulnerable

More Vulnerable

Less Vulnerable

Flood Zone

Zone 1

Zone 2 Exception

Test required

Zone 3a Exception Test

required

Exception Test

required

Zone 3b Exception Test

required

Development is appropriate Development should not be permitted

In accordance with the vulnerability table above, the development is deemed to be appropriate for the site.


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3.0 Site Details

3.1 Location The site is centred on ordnance survey grid reference SD 878 215. An Ordnance Survey plan, indicating the location of the property is presented below.

Figure 1: Location Plan – New Line, Bacup

Image produced from the Ordnance Survey Get‐a‐map service. Image reproduced with kind permission of Ordnance Survey and Ordnance Survey of Northern Ireland.

Proposed Development


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3.2 Former/Current Use From the 1893 historical map of the proposed development it has been established that the site formerly accommodated the Park Mill and Albert Shed Cotton Mills; along with a Saw Mill with a large undeveloped area lying centrally between the mill buildings. By 1930 the maps indicate that the layout of the site remained relatively unchanged, with building extensions to the Saw Mill and Park Mill, within the west part of the site. During more recent history, aerial photographs of the site taken 2000‐2005 (see Appendix B) indicate that by this time the Park Mill buildings had been demolished; however few changes had been made to the historic layout of the site off New Line. Observations made during a site visit in October 2011, indicate that the former Saw Mill and part of the Albert Mill buildings were demolished after 2005. A topographical Survey of the existing site is provided within Appendix A of this report.

Figure 2: Historical Map of the Development Site (Circa 1893)

Image courtesy of www.oldmaps.co.uk


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3.3 Proposals Proposals for development at the site comprise 32No residential units, with an access road leading from New Line; and associated accessway and shared driveways. An area within the south west part of the site has been set aside for wetland attenuation. The proposed development layout plan has been provided within Appendix C of this report.

3.4 Boundaries

The subject site is situated within an area known as Britannia, within the eastern fringe of Bacup, a small town within the Rossendale Borough of Lancashire. The centre of Bacup is situated approximately 1.8 kilometres to the north west of the site. The northern boundary of the site is formed by a highway known as New Line; with the remnants of an existing cotton mill along Deansgreave Road forming the east boundary. 2No existing residential properties (No’s 137 & 139 New Line) are also located along the north boundary of the site. The Rochdale and Facit Railway was extended to Bacup in 1883, and closed in 1947. The route of the former railway cutting now forms a leisure route between the areas of Bacup known as Britannia and New Line Reservoir. Britannia Beck flows westwards along the south side of the former railway cutting and outfalls into New Line Reservoir at a distance approximating 150 metres downstream from the west boundary of the development site. An unnamed culverted watercourse bisects the development site. It enters the site along the east boundary and arcs in a south westerly direction through the rear gardens of No’s 137 & 139 New Line; discharging into Britannia Beck along the south west boundary of the site. As the watercourse passes through the garden areas, it is observed to flow via an open channel. Vehicular access into the site is currently available from New Line. Beyond its immediate boundary, the development in general is surrounded by open landscape comprising agricultural farmland and moorland.


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3.5 Topography A topographical survey of the existing site was undertaken in September 2011 and reveals a ground level of 288.116mAOD at the north east corner; a high point of 290.00mAOD within the south east corner; and a low point of 282.612mAOD within the south west corner of the site. Levels along the south boundary range from 290.00mAOD (east) down to 282.612mAOD (west). Man‐made spoil heaps are located within the eastern part of the existing site; which are elevated above normal site levels; with the top of the northernmost spoil heap achieving a crest level of 289.63mAOD. External ground levels at the front door accesses into the existing residential properties along New Line are 286.031mAOD; and 285.974mAOD respectively. Access into the properties appears to be level; and therefore a ground floor level of 286.00mAOD has been adopted for the purposes of this assessment. The properties step down to the rear; with external levels ranging from 282.947mAOD – 283.642mAOD. Through discussion with the Environment Agency it is understood that levels have largely been elevated above historical ground levels within the site boundary.

3.6 Existing Drainage It is understood that former industrial development within the site discharged surface water via a positive system into an unnamed watercourse which traverses the site. Unfortunately during previous demolition and earthworks operations at the site, evidence of the connections from the development into the watercourse has been removed. Information obtained from United Utilities indicates that there is an existing 375mm diameter public combined sewer flowing westwards along New Line. Similarly a 225mm diameter public combined sewer is located within Deansgreave Road, which serves the remaining mill buildings situated along the east boundary of the development site. A 225mm diameter public surface water sewer is shown to enter the site along the north boundary, and discharges into a culverted section of the unnamed watercourse. This sewer is shown to serve residential property along Cobden Street to the north.


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Figure 5: Existing Site Viewed East from South West Boundary

Photograph taken 26/10/11

3.7 History of Flooding

3.7.1 British Hydrological Society – Hydrological Events A search on the British Hydrological Society Chronology of British Hydrological Events website (http://www.dundee.ac.uk/geography/cbhe) indicates numerous incidents of flooding within the Bacup area, the most notable of which include the following:

August 1849 – the River Irwell flooded

July 1870 – Flash flooding cause devastation to many of the mill buildings; businesses and homes along the route of the River Irwell.

3.7.2 Internet Search for Historical Flooding Undertaking an internet based search for flooding indicated that the small town of Bacup was also badly affected by flooding during July 1881; September 1935; and December 1936.


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During the flood of December 14th 1936 the town of Bacup was reported to have experienced the worst floods for the previous fifty years. Flooded houses, cellars and shop premises were the order of the day in Bacup with one mill having to close due to the depth of water. The River Irwell became so swollen, following continuous heavy rain throughout the night and morning, that it overflowed about 12:30p.m and rushed like a torrent down Burnley Road, the flooding accentuated by fact that some of the road gullies were unable to take the storm water. At the entrance to St James Square the water divided into two streams which swept round the square and into St James Street, and subsequently Union Street. Several houses were flooded. The extent to which they were inundated can be judged from the experience of one resident, who commented that the flood water had been "up to her knees ".

3.7.3 Rossendale SFRA Records of historical flood events have been collated as part of the Rossendale SFRA. The details of flooding incidents within the Bacup area have been extracted from Appendix A of the SFRA document and provided within Table 2 below. It is noted however that no flooding incidents were recorded within the immediate vicinity of the proposed development off New Line. Table 2: Historical Flood Events

Date Watercourse/Location Source of Flooding & Impact Most well documented floods of 1866, 1946, 1954, 1980 &

2007

River Irwell – Rossendale Valley

Fluvial

August 1849 Upper Irwell ‐ Bacup Fluvial

July 1870 Upper Irwell ‐ Bacup Fluvial – heavy lightening storms and steep valley sides brought ‘catastrophic’ results

July 1881 Upper Irwell ‐ Bacup Fluvial – ‘catastrophic results’. Mill properties along Burnley

Road severely damaged

August 1891 Upper Irwell ‐ Bacup Fluvial – streets flooded 2ft deep, mills were stopped.

November 1895 Upper Irwell ‐ Bacup Fluvial – quoted as ‘the greatest flood for 20 years’

June 2002 River Irwell – Bacup town centre, junction of Burnley Road, Yorkshire Street and St

James Street

Fluvial – channel capacity exceeded (no raised defences)


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Table 2 cont’d

June 2002 Broad Clough – unnamed watercourse Burnley Road,

Bacup

Surface water or fluvial –flooded track to rear of Broad

Clough Villas

June 2002 Unnamed watercourse – Mil Street & Holmes Lane, Bacup

Fluvial – flooded leisure centre

January 2008 River Irwell ‐ Bacup Fluvial – house along Rochdale Road flooded

3.7.4 Culvert Repair Works at Bacup In April 2010, the Environment Agency reported completion of culvert repair works in Bacup, which were undertaken to help manage the risk of flooding in the town. The £350,000 improvement project has increased the lifespan of the underground river channel at St James Street, which is over 150 years old, and is estimated to reduce the flood risk to around 60 properties in the town centre. The improvements comprised the resetting, re‐pointing and grouting of the stonework which makes up the culvert; and it was anticipated that without the repairs there was an increased risk that some of the stonework could collapse. If this happened it could have caused a blockage in the river, and may have led to flooding from the River Irwell to the town centre. In June 2002 twenty five properties were partially flooded due to this kind of blockage. These repairs form part of the Environment Agency’s published strategy for managing flood risk in the Upper Irwell area which includes carrying out culvert repairs and monitoring for any other damage within the watercourse.


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4.0 Flooding Mechanisms Table 3: Sources of Flooding

Source/Pathway Significant? Comment/Reason

Fluvial Yes Britannia Beck; unnamed watercourse

Tidal/Coastal No

Canal No

Pluvial (urban drainage) Yes Site was positively drained prior to demolition works

Groundwater No

Overland flow Yes Due to topography of the area – there is potential for flooding via this mechanism

Blockage Yes Culverted watercourse

Infrastructure failure Yes Culverted watercourse

Rainfall Ponding Yes Existing areas of ponding observed at the site

4.1 Britannia Beck Britannia Beck is a tributary of the River Irwell, and flows generally in a westerly direction along the south boundary of the proposed development. The watercourse starts within the area of Bacup known as Britannia, and serves to collect water via a network of small unnamed watercourses from the surrounding moorland area. The beck is predominantly open channel and is conveyed within a former railway cutting as it flows past the development site. Downstream from the development, the watercourse is culverted for a short length before emerging into an open area of water known as Britannia or New Line Reservoir. Another network of moorland streams collectively known as Venomous Clough, also discharge into the reservoir, along its south bank. Britannia Beck continues its route downstream from the reservoir first in a northward direction across New Line; continuing west via culvert through industrial development at The Sidings; then further west via alternating open channel and culverted sections, ultimately joining with the River Irwell at New Church Road. Adjacent to the south development boundary, the north bank of the watercourse ranges in level from 277.80mAOD up to 285.53mAOD. Corresponding levels along the south boundary of the development site range from 282.612mAOD to 290.00mAOD. The site is therefore elevated in excess of 4 metres above the channel of the watercourse.


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It is considered therefore that Britannia Beck presents a low flood risk to the proposed development.

4.2 Fluvial – Unnamed Watercourse

4.2.1 General A small tributary of Britannia Beck is found to traverse the proposed development. The watercourse collects water from a network of springs and small streams originating on moorland located to the north east of the site. As the watercourse flows through the development it is largely culverted, with an open channel section to the rear of the existing residential properties located along the north boundary.

Figure 6: Open Channel Section of Watercourse to the Rear of Existing Residential Properties


The watercourse ultimately discharges into Britannia Beck along the south west boundary of the development via a stone arch outfall.


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Figure 7: Outfall into Britannia Beck


Upstream of the open channel section, the watercourse is culverted via a 1.6m diameter pipe; and downstream via 1.85m diameter pipe, which connects to the original stone arch culvert at a manhole chamber within the west part of the site. In order to ascertain the risk to the site from this potential flood source, the capacity of the open and culverted sections of the channel under normal flood conditions; along with a blockage scenario will be investigated in detail within this report.

4.2.2 Estimation of 1 in 100 year Flow within the Unnamed Watercourse It is necessary to estimate the 1 in 100 year flow within the existing culvert in order to evaluate the flood risk posed by the culvert and the small section of open channel within the development site. IOH124 Method for Small Catchments Using FEH CD‐ROM (Version 3.0), the catchment serving the watercourse is very small at 0.61 km2 and essentially rural in nature and therefore flow has been estimated using the IOH124 Method for calculation flows from small catchments.


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QBAR is estimated using Equation 4‐1, outlined below.

Equation 4‐1

QBARRURAL = 0.00108AREA

0.89 SAAR 1.17 SOIL 2.17

Where QBAR RURAL = mean annual flood in the as‐rural state AREA = catchment area (km2) SAAR = standard average annual rainfall (mm) SOIL = soil type index

The full calculation results for QBAR rural obtained from the IOH124 method, is given in Appendix G of this report. A value of 0.299m³/s has been estimated. The catchment consists of <5% urbanisation and as such an adjustment to the QBAR is not required. Therefore the 1 in 100 year flow within the unnamed watercourse through the site is estimated as 0.621m³/s. Consideration has been given to take into account the potential effects of future climate change and sea level rise in accordance with PPS25. A 1 in 100 year plus climate change return period incorporating the precautionary sensitivity range of a 30% increase in rainfall intensity and peak river flows recommended by PPS25, provided a design flow of 0.807m³/s.

4.2.3 Capacity of the 1600mm Diameter Culverted Watercourse From the topographical survey information, the upstream section of culvert comprises a 1600mm diameter pipe. Unfortunately the gradient of the culvert is unknown; and therefore a gradient of 1 in 1888, which exhibits a self‐cleansing velocity of 1m/s, has been used in order to undertake an assessment of the capacity of this section of the watercourse. Using Colebrook‐White, it is estimated that the maximum capacity of the existing culvert is approximately 2.04m³/s. During the 1 in 100 year plus 30% climate change event, it is anticipated that the proportional depth of flow within the culvert is 0.436. Therefore at the opening into the open channel section of watercourse, the corresponding flood level is estimated at 282.474mAOD. Consequently during the 1 in 100 year and 1 in 100 year plus climate change flood events, the capacity of this culverted section of watercourse are unlikely to be exceeded.


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4.2.4 Capacity of the Open Channel Section of Watercourse The Manning Equation has been used to calculate the capacity of the channel within the rear gardens of existing residential property located along the north boundary of the site i.e. 137 & 139 New Line. On emerging from the 1600mm diameter culvert, the channel of the watercourse widens, and flows westwards through the rear gardens. During the site visit, it was noted that observation of the open channel at this location was severely impaired due to decking within the residential garden. A photograph illustrating this section of open channel is provided within Figure 6. The first calculation undertakes to evaluate the channel capacity along the east side of the residential gardens.

Equation 4‐2 Manning’s Equation: Q = (A*r2/3*s1/2) / n A = Cross sectional area of channel = 4.433m2 P = Wetted perimeter of channel = 5.9056m r = A/P = 0.751 s = average channel slope = 0.981m fall over 24.9m = 0.039 n = Manning’s coefficient of roughness = 0.070 (mountain stream – cobbles and large boulders). Q = 10.4m³/s

It was estimated; using Manning’s equation that the maximum capacity of the open channel upstream at this location is approximately 10.4m³/s, and consequently during the 1 in 100 year and 1 in 100 year plus climate change flood events, the channel capacity is unlikely to be exceeded. The corresponding water level within the open channel is estimated to be 282.158mAOD during the 1 in 100 year plus 30% climate change event; and is therefore 1.2m and 3.8m respectively below the decked garden and ground floor level within the properties.


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Figure 8: Cross Section Through Open Channel Upstream of Residential Gardens.

The open channel exits the rear garden areas of the existing residential properties via an opening in the wall which forms the west boundary of the existing properties, as illustrated within Figure 9. This acts to restrict flows passing downstream. The dimensions of the opening were measured at 1.45m (wide) x 0.75m (high). Assuming that free surface flow is maintained through the opening, using Manning’s Equation, the capacity of the opening is estimated to be 1.47m3/s.

Equation 4‐3 Manning’s Equation: Q = (A*r2/3*s1/2) / n A = Cross sectional area of channel = 1.0326m2 P = Wetted perimeter of channel = 2.8746m r = A/P = 0.359 s = average channel slope = 0.981m fall over 24.9m = 0.039 n = Manning’s coefficient of roughness = 0.070 (mountain stream – cobbles and large boulders). Q = 1.47m³/s


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Figure 9: Cross Section Through Channel Downstream of Residential Gardens.

Figure 10: Photograph Illustrating Watercourse Exiting from the Existing Residential Gardens.

In order to establish the headwater and tailwater levels either side of the opening, HY‐8 Culvert Analysis software has been utilised. Analysis confirms that the opening has sufficient capacity to convey the 1 in 100 year plus 30% climate change flow, and indicates that the corresponding headwater level within the existing residential properties is 281.32mAOD.


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This water level is approximately 1.2m and 4.7m respectively below the crest of the garden wall and ground floor level within the properties. The opening in the garden wall acts as a throttle and therefore the flow depth is shown to increase as water passes downstream. However under normal conditions, the flood risk to the No’s 137 & 139 New Line from the open section of watercourse is considered to be low.

4.2.5 Capacity of the 1850mm Diameter Culverted Watercourse The downstream section of culvert comprises a 1.85m diameter pipe, set to a gradient approximating 1 in 200. Using the Colebrook‐White Equation, the capacity of the downstream section of culvert is estimated to be 9.3m3/s; and exhibits sufficient capacity to convey the 1 in 100 year plus 30% climate change flow estimated as 0.807m3/s. From the calculations, it is anticipated that the corresponding proportional depth of flow within the culvert during such an event is 0.145. Therefore at the head of the culvert, the corresponding flood level is estimated at 281.050mAOD. In conclusion, during normal conditions both the culvert and the open channel sections of the watercourse are considered sufficient to convey the flows during the 1 in 100 year and the 1 in 100 year plus climate change events without out of bank flooding occurring.

4.2.6 Blockage The Environment Agency has expressed concern relating to flooding at No’s 137 & 139 New Line, resulting from blockage within the culverted sections of the unnamed watercourse. Wall Opening Should a partial blockage of the wall opening along the west boundary of the existing houses occur, reducing the cross sectional area for example by 50%, the capacity of the opening will be reduced to approximately 0.561m3/s. Using the HY‐8 Culvert Analysis Software, the headwater level during a blockage of this nature, will increase to approximately 281.51mAOD. Whilst the water level is slightly increased when compared to normal conditions, the flood risk to the existing residential properties is considered to remain low. Downstream Culvert (1.85m Diameter) Similarly, should a blockage of the downstream section of culverted watercourse occur, reducing the cross sectional area again by 50%, the capacity of the culvert will be reduced to approximately 3.7m³/s.


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As such, the capacity of the culvert remains sufficient to convey flood water during the 1 in 100 year and 1 in 100 year plus climate change flood event. During the site visit, observations of the inlet and outlet arrangements of the existing culverts were visually obscured due to steep banks and overgrown vegetation; and therefore it is unknown whether trash screens have been incorporated into the existing headwall construction. It is recommended that trash screens at the headwall of 1.85m diameter culvert; and also within the upstream end of the open channel section, where it flows beneath the decked rear garden area within the residential properties. The installation of trash screens will significantly reduce the likelihood of blockage from occurring within the watercourse; thereby lowering further the flood risk to the adjoining residential properties along the north boundary of the site.

4.3 Surface Water Runoff 4.3.1 Increased Runoff Due to Development Former development within the site comprised mill buildings which have now been demolished. It is understood that this former industrial development discharged surface water via a positive system into the unnamed watercourse which traverses the site. However, during previous demolition and earthworks operations at the site, evidence of the connections from the development into the watercourse has been removed. Following development, it is anticipated that the extent of the paved areas within the site will be increased and therefore surface water runoff rates and volumes are also likely to be increased. The Environment Agency has advised that surface water leaving the proposed development should be restricted to 13l/s/ha. The gross development area covers an area approximating 1.15 Hectares; therefore the total outflow should be restricted to a rate of 15l/s. Flows in excess of this should be attenuated on‐site prior to discharge into the receiving watercourse. The Environment Agency and Local Authority will insist that the proposed 1 in 2 year runoff can be maintained and also insist that the 1 in 30 year event is not allowed to flood the surface; hence the water must remain within the pipes, manholes, and storage systems.


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It is usual practice to allow the 1 in 100 year plus climate change event to flood the surface but flood water will not be permitted to enter any of the buildings within the site. The 1 in 100 year plus climate change flood must also be limited to the development boundary and must not be allowed to migrate to adjacent properties. In order to ascertain the attenuation requirements of the proposed development the Wallingford Procedure, Modified Rational Method has been utilised to estimate storage volumes for the 1 in 2 year, 30 year, 100 year and 100 year plus climate change events. The calculation results are tabulated below. From the development proposals provided by Harron Homes, it is estimated that following development, the area contributing to surface water flows is approximately 0.52 Hectares i.e. 45% of the gross development area. Table 4: Indicative Volumes of Attenuation

Return Period Storage Volume (l/s)

1 in 2 year 30

1 in 30 year 172

1 in 100 year 265

1 in 100 year + 30% climate change 381

Flows from the attenuation structure are to be controlled via an orifice plate, Hydrobrake or similar flow control unit. It is noted that the storage volumes provided are indicative only at this stage and should be recalculated during the detailed design stage to reflect the agreed allowable discharge from the site, the actual development proposal, the extent of impermeable areas and runoff to be generated.

4.4 Overland Flow Higher Hogshead is situated to the north east of the proposed development, with a crest elevation of 445mAOD. From the Ordnance Survey Maps for the area, it is identified that surface water from the moor is collected by a network of minor watercourses which culminate in a single unnamed watercourse, which traverses through the proposed development; towards Britannia Beck and ultimately to the River Irwell. Analysis of the watercourse through the site indicates that is has sufficient capacity to convey flows generated within the moorland area surrounding the site and therefore this potential flood mechanism is not considered to present a flood risk to the development.


24

4.5 Ponding During a site walkover, shallow ponding was observed. It is noted that the walkover was conducted following a period of heavy rainfall and therefore; the areas of ponding were considered to be surface water accumulation at isolated low spots throughout the site. Following development it is anticipated that the existing low spots within the site will be engineered out during the construction works and as such ponding is considered to present a low flood risk to the proposed development.


25

5.0 Material Consideration In Respect of PPS25

5.1 Climatic Change Annex A of PPS25 suggests that winters will become wetter over the whole of the UK, by as much as 20% by the year 2050. In making an assessment of the impact of climatic change, flooding from rivers and land will give a peak flow allowance of up to 20% increase in rainfall for a given return period by 2050 and 30% by 2110. These considerations will provide an appropriate precautionary assessment for climatic change impact on flood flows and rainfall intensities.

5.2 Environment Agency Flood Map

Figure 11: Environment Agency Flood Map

Source: Environment Agency website (http://www.environment‐agency.gov.uk/subjects/flood)

Key

Flooding from rivers or sea without defences (Flood Zone 3)

Extent of extreme flood (Flood Zone 2)

Flood defences

Areas benefiting from flood defences

Main rivers

Proposed Development Site


26

The Environment Agency flood zone map indicates that the site lies within Flood Zone 1, being the zone comprising land as having less than the 1 in 1,000 annual probability of river or tidal/coastal flooding in any year (<0.1%).

5.3 Finished Floor Levels The proposed residential development is located within Flood Zone 1, of the Environment Agency Flood Map. Therefore it is considered that raising ground levels within the proposed development is not required. However, it is recommended that the internal ground floor level of the proposed residential units are elevated a minimum of 150mm above the adjacent external finished ground level, to mitigate against any localised flooding which may be caused by heavy rainfall.

5.3 Emergency Access and Egress during Times of Flood The site of the proposed development and surrounding area is located within Flood Zone 1, therefore it is considered that dry access and egress from the site is available at all times.

5.4 Preliminary Drainage Strategy The impermeable area and hence surface water flows from the proposed development are considered to increase following completion of the development. The hierarchy for disposal of surface water from new development is outlined within The Building Regulations Approved Document H (2002) and specifies the following methods in order of preference:

Infiltration via soakaway or other suitable infiltration device

Discharge to watercourse

Discharge to public sewer.

5.4.1 Infiltration It is understood that site investigation works at the proposed development have been previously carried out; however this information is not currently available. Therefore in order to assess the potential for infiltration methods to dispose of surface water from the development, an investigation of the general ground conditions within the Bacup area surrounding the development was undertaken. Catchment wide data for the site was obtained from the FEH CD‐ROM (V3.0), which indicates that, the SPRHOST (Standard Percentage Runoff) for the site has a value of 32.2%. This value is fairly high and from experience is generally considered to represent ground which is fairly impermeable.


27

Further investigation via review of historical borehole logs near to the proposed development site, from the British Geological Society, records indicates that below made ground there is a substantial layer of clay overlying sandstone which comprises a minor aquifer. The south boundary of the site exhibits a significant drop in elevation into a former railway cutting now utilised for leisure purposes. Britannia Beck flows in a westerly direction along the route of the railway cutting, and during the site visit, the emergence of groundwater from the wall of the cutting, was observed. It was noted that this was more prevalent along the south side of the watercourse. As such, to prevent seepage from occurring along the south boundary, the disposal of surface water from the proposed development via soakaways is considered to be impractical; and this method has been discounted from the proposed drainage strategy for the site. A copy of the historical borehole logs are provided within Appendix M of this report.

5.4.2 Discharge to Watercourse There is evidence available from the sewer record plans for the area, that surface water from the surrounding developed area is directed into the extensive network of small watercourses present within the Irwell Valley. Furthermore, through discussion with the EA it is agreed that surface water from the former buildings within the site, was discharged into the unnamed watercourse which traverses the site. Therefore it is proposed that surface water from the new development will discharge into the unnamed watercourse.

5.4.3 Attenuation of Flow An allowable discharge rate of 13l/s/ha has previously been agreed with the EA. The gross area for development is estimated to be 1.15Ha; therefore the maximum rate of discharge into the watercourse is calculated to be 15l/s. In order to compensate for culverting of the unnamed watercourse, the EA requires attenuation of surface water flows to be undertaken using a pond or wetland structure.


28

Pond/Wetland Attenuation Using the topographical and preliminary site layout for the development; the ideal location for placement of a pond or wetland structure is within the low lying area at the south west corner of the site. Using a plan area for the structure of 415m2; and using MicroDrainage Source Control, the depth of water within the wetland or basin during the 1 in 2 year; 30 year; and 100 year plus 30% climate change event is estimated to be 0.274m; 0.565m; and 0.753m respectively. Flow is restricted to a maximum of 15l/s during the 1 in 2 year; 30 year; and 100 year plus climate change events. In order to prevent inundation of existing residential development located to the north of the proposed pond/wetland, during extreme rainfall events, a high level overflow pipe should be incorporated into the pond/wetland design. Testing the sensitivity of the preliminary pond design indicates that the overflow becomes operational for events with a probability of 1 in 125 years. During the extreme 1 in 1000 year event, outflow from the pond is increased to 37l/s; however overtopping is unlikely. Due to the residential nature of the final development; concerns may be raised regarding the dangers associated with open water within the close vicinity of children. Therefore in order to deter unauthorised persons from accessing the pond/wetland area it is advisable to provide substantial fencing around the perimeter of the structure.

5.5 Sustainable Urban Drainage (SUDS) The impermeable area within the site will increase following development. And as such, the management of surface water runoff from the development is considered to be paramount. The Environment Agency will require that adequate pollution control is incorporated into the drainage system in order to prevent deterioration of the quality of the water environment. The incorporation of a pond or wetland structure into the drainage strategy for the site will provide this required element. To reduce the impact of surface water runoff from the development in accordance with the requirements of the Environment Agency and Local Authority, the employment of SUDS techniques to limit runoff volumes and rates from the site are recommended. SUDS techniques can also be used to provide an appropriate level of treatment to the runoff. It is normal practice to ensure that the 1 in 30 year plus climate change event is maintained within the drainage system and the 1 in 100 year plus climate change is permitted to flood the surface as long as there is no flooding to buildings and the flood volume is contained within the site boundary in specific areas proposed for this purpose.


29

The following section provides an indication of the possible SUDS techniques which could be employed on the site to balance flows within the proposed development. SUDS techniques are also able to provide treatment to the runoff to remove a proportion of the pollution and protect the quality of the downstream watercourses. Following guidance from CIRIA Report C522 the following levels of treatment will be provided:

• Roofs – 1 level • Driveways – 1 level • Roads and communal parking areas – 2 levels.

The level of treatment indicates the number of SUDS techniques that will be used to treat pollution. For example if two levels are required the runoff may enter a filter drain that leads to a basin or pond before outfall. The Environment Agency and Local Authority will recommend the use of SUDs techniques within the drainage strategy for this development. Implementation of source control techniques means in practice there will be little outflow for a 1 in 2 year storm as most of the rainfall will be held within the system and will disperse via evapotranspiration. A suitability matrix has been used to quickly identify SUDs techniques which may be investigated further for incorporation into the drainage strategy for the proposed development. The results from the analysis are summarised below within Table 5, and the completed matrix is provided for information within Appendix L of this report. The precise combination of methods used will be dependent upon the site constraints identified at the final design stage. In summary the following methods for dealing with surface water from the development site are found to be the most suitable:

Retention – pond; basins and sub‐surface storage.

Wetland –all types of wetland.

Filtration – surface; sub‐surface; bio‐retention filter trenches; and filter trenches

Source Control – green roof technology; rainwater harvesting; and permeable pavements

5.5.1 Ponds and Wetlands Ponds contain water in dry weather, and are designed to hold more when it rains. They include:

Balancing and attenuation ponds

Flood storage reservoirs

Lagoons

Retention ponds

Wetlands


30

Ponds and wetlands store water at the ground surface, either as temporary flooding of dry basins and flood plains, or permanent ponds and wetlands. These structures can be designed to manage water quantity and quality.

Figure 12: Simplified Section Through a Pond or Wetland

Ponds and wetlands can be designed to control flow rates by storing floodwater and releasing it slowly once the risk of flooding has passed. The stored water will change the water level, and structures should be designed to function in both dry and wet weather. Quantity can also be influenced by the amount of water that can be allowed to infiltrate into the ground if there is no risk to groundwater quality. Basins and ponds treat runoff in a variety of ways:

settlement of solids in still water ‐ having plants in the water enhances calm conditions and promotes settlement

adsorption by aquatic vegetation or the soil biological activity

Ponds and wetlands offer many opportunities for the landscape designer. Basins should not be built on, but can be used for sports and recreation. Permanently wet ponds can be used to store water for reuse, and offer excellent opportunities for the provision of wildlife habitats. Both basins and ponds can be part of public open space.


31

Table 5: SUDS Techniques and Suitability of Use

Method Description Potential for use at site

Filter drains

Drainage trench filled with gravel and provided with a pipe

Ground conditions indicate poor permeability, however sand filters and bio‐retention filter trenches are shown to be potentially suitable.

Swales

Shallow grass ditch The size of the development coupled with the potential head across the development makes this SUDs technique unsuitable for use within this particular site.

Permeable surfaces

Pavement surfaces that allow water to pass through into underlying storage in sub base e.g. permeable concrete block paving or porous asphalt.

Ground conditions indicate poor permeability for infiltration. Permeable paving may be considered for use within the communal parking areas to reduce the volume of on‐line attenuation required.

Ponds; basins; & wetlands

Open areas that are used to store and treat rainwater. Ponds are permanent bodies of water and basins are generally dry and occasionally store water.

The Environment Agency has requested that a pond or wetland structure is utilised for attenuation of surface water flows within the drainage strategy for the proposed development.

Green roofs

Roof system that is vegetated with plants (note sedum plants rather than grass so no mowing is required)

Development involves the provision of residential units; therefore may not be practical for inclusion within the drainage strategy; and is largely dependant upon the final architectural design of the housing units.

Rainwater Harvesting

Rainwater re‐use to provide a non‐potable water supply

The proposed development will increase the volume of surface water runoff from the site; rainwater harvesting may be incorporated to reduce the volume to pre‐development levels.

Infiltration devices

Methods that allow rainwater to soak into the ground, e.g. soakaways.

Ground conditions indicate poor permeability.

Storage tanks Underground tanks that temporarily store water in the drainage system.

May be considered for use if other SUDs techniques are found to be unsuitable for the site.


32

5.5.2 Green Roof Green roof refers to a system of roofing that uses plant life for roof covering instead of traditional covering materials. The system of green roofing dates back to the 1960’s but only in recent years it has became a popular alternative to the traditional roofing due to its environmental benefits and savings for heating and cooling. The plants that cover the roof provide an excellent insulation to the building but they also act as a natural filter for rainwater which means that they significantly reduce the volume of surface water runoff leaving the site, as the plants absorb as much as 50% of rainwater which would otherwise run into the proposed drainage system The water that is absorbed by the plants on the rooftop may then evaporate back into the atmosphere. According to plant selection, there are three main green roof types called intensive, semi‐intensive and extensive. Intensive green roofs refer to rooftops that accommodate large plants including trees, full lawn, etc. This type of green roofing requires a significant depth of soil as well as lot of maintenance, similar to maintaining a park or large garden. Semi‐intensive green roof involves roof covering with plants of moderate size and requires less maintenance. Extensive green roof is the most convenient of all types of green roof systems and involves roof covering with a thin layer of growing medium and vegetation that requires minimal care and maintenance. Green roof technology is considered in general to be more suited to retail, commercial and industrial application. The development is residential in nature and is largely dependant upon the design of the buildings; as such the implementation of this SUDs technique within the drainage strategy for the site will ultimately be determined by the Architect.

5.5.3 Rainwater Harvesting Following development the volume of surface water runoff leaving the site is likely to be increased; owing to an increase in roof and hardstanding areas within the site. It is therefore recommended that should green roof technology be found unsuitable for use within this development, then rainwater harvesting is implemented as a source of non‐potable water. This will act to reduce the volume of surface water leaving the proposed development; thereby helping to alleviate the current pressures on the receiving watercourse.


33

5.6 Foul Drainage It is proposed that foul drainage from the proposed development will be directed to the public combined drainage system within New Line, along the north boundary of the site.

5.7 Maintenance In order to prevent localised flooding from occurring within existing residential properties adjacent to the open section of the unnamed watercourse resulting from blockages, it is recommended that regular inspection and maintenance of the inlets/outlets of the culverted sections of watercourse; and proposed wetland structure is undertaken. Such maintenance works may include cutting back vegetation and removal of debris from the open channel sections of the watercourse; and inlet/outlet arrangements within the proposed wetland; within the boundary of the site. Following a discussion with the drainage authority, United Utilities will adopt the proposed surface water system serving the development up to the outfall into the wetland; however all structures beyond the outfall, including the flow control chamber must be maintained by a management company.

5.8 Easements The Environment Agency requires a minimum easement of 3 metres either side of the culverted watercourse to enable periodic inspection and essential maintenance to be undertaken. Similarly a 3 metre easement either side of the 225mm diameter public surface water sewer entering the site along the north boundary is required by United Utilities.


34

6.0 Conclusions and Recommendations

6.1 The proposed development covers a gross development area of 1.15 Hectares, within land off New Line; Bacup is located within Flood Zone 1 of the Environment Agency Flood Map.

6.2 The primary source of flooding at the development is identified from an unnamed watercourse which traverses the site; and an increase in surface water runoff from the development area.

6.2 The unnamed watercourse is a small tributary of Britannia Beck; and collects runoff

from a small moorland catchment area situated to the north east of the development site.

6.3 The watercourse is intermittently conveyed through the site via open channel and

culverted sections, discharging into Britannia Beck along the south west boundary of the site.

6.4 Utilising the IOH124 Method for small rural catchments, the 1 in 100 year plus 30% climate change flow within the unnamed watercourse is estimated to be 0.807m3/s.

6.5 The unnamed watercourse enters the site via a 1.6m diameter culvert; which exhibits a maximum capacity of 2.04m3/s. This culvert opens out into an open channel through the rear gardens of existing residential properties, located along the north boundary of the site. On the upstream side of the properties, it is estimated that the channel has a capacity approximating to 10.4m3/s.

6.6 The open channel flows beneath existing garden decking; emerging via a rectangular opening in the boundary wall with dimensions 1.45m (wide) x 0.75m (high). Using Manning’s Equation, the capacity of the opening is estimated to be 1.47m3/s.

6.7 There is a small section of open channel, prior to a second culvert (1.85m diameter),

which conveys the watercourse south west across the site, to its confluence with Britannia Beck. The capacity of the culvert is estimated to be 9.3m3/s.

6.8 In conclusion, under normal conditions, the watercourse is deemed to possess sufficient capacity to convey the 1 in 100 year plus 30% climate change flows; and hence presents a low flood risk to the proposed development.

6.9 Using HY8 Culvert Analysis, it is indicated that during a 50% blockage at the wall

opening; the water level within the open channel section adjacent to No 137 & 139 New Line is approximately 1 metre below the level of the rear garden and 4.5 metres below the ground floor level within the properties.


35

6.10 Furthermore a 50% reduction in cross sectional area within the 1.85m diameter

downstream culvert still provides sufficient capacity for the 1 in 100 year plus 30% climate change flow within the watercourse. Therefore it is concluded that the unnamed watercourse presents a low flood risk to the development and immediate surrounding area.

6.11 Following development, the impermeable area within the site will be increased to an

area covering 0.52 Hectares or 45% of the gross development area; and hence surface water runoff rates and volumes will also be increased.

6.12 The Environment Agency has requested that surface water from the proposed development is restricted to 13l/s/ha; equating to a maximum rate of 15l/s over the whole development area.

6.13 Flows in excess of this will need to be attenuated within the site. 6.14 The proposed drainage strategy for the development involves the incorporation of

wetland storage prior to discharge into the receiving watercourse; with flows leaving the site controlled via a Hydrobrake or similar flow control structure.

6.15 Calculations indicate that the maximum depth of water within the wetland structure

is 0.753m during the 1 in 100 year plus 30% climate change event.

6.16 To prevent overtopping of the open wetland structure during extreme flood events; it is proposed that an overflow pipe is incorporated into the design; in order to prevent inundation of existing nearby residential properties.

6.17 It is recommended that a regime for maintenance will need to be established for regular inspection and maintenance of the culverted watercourse; and proposed wetland area, in order to reduce the risk of flooding caused by blockage.

6.18 Such maintenance works may include cutting back vegetation and removal of debris

from the open channel sections of the watercourse; and inlet/outlet arrangements of the proposed wetland; within the boundary of the site.

6.19 It is proposed that domestic foul flows from the development are discharged via the new access into the existing 225mm diameter public combined sewer within New Line to the north of the site.

6.20 The Environment Agency has requested that an easement of 3 metres either side of the culverted watercourse is provided. Furthermore a 3 metre easement also needs to be provided either side of the 225mm diameter public surface water sewer which enters the site along the north east boundary.


APPENDIX A Existing Site Layout: Topographical Survey


APPENDIX B Ariel Photographs of the Site

(Circa 2000 & 2005)

Aerial Photograph (Circa 2000)




APPENDIX C Preliminary Site Layout


APPENDIX D United Utilities Sewer

Record Plans

T-JUNCTION(SADDLE)

ABANDONED SEWER

MANHOLE

SIDE ENTRYMANHOLE

LAMP HOLE

DUAL

PENSTOCK

OIL INTERCEPTOR

RODDING EYE

SOAKAWAY

TUMBLING BAY

UNSPECIFIED

VALVE

GHOST NODE (inc. GN - Rising Main & GN - Dual Function)

CONTROL VALVE

GULLEY

EXPEDIENCY NODE (CHANGE OF CHARACTERISTIC)

CONTROL KIOSK

PUMPINGSTATION

DISCHARGE POINT(OUTFALL)

VENT COLUMN

SEWEROVERFLOW

EJECTOR STATION

SLUDGE PUMPING STATION

WASTE WATERTREATMENT WORKS

WASTE WATER SYMBOLOGY

PRIVATE SEWER

SIDE ENTRY CATCHPIT

SIDE ENTRY CHAMBER

SIDE ENTRY DROPSHAFT

WASHOUT

DROPSHAFT

CATCHPIT

CHAMBER

COMBINED FOUL

TANK

SITE TERMINATION

SURFACE

AIRVALVE

SHEET EDGE

HATCHBOX

HEADWALL

HYDROBRAKE

INLET

CASCADE

Trapezoidal

Ghost(to allow pipe bends)

GQ Expediency Node

Ghost in Rising Main

Vent Column

YEOI

T

HorseshoeUnspecified

Hydrobrake

Cascade

OverflowTransition

Unspecified

GulleyEjectorOil InjectorInlet

B

ValveUnspecified

XU

BArchBarrel

A

U

T

H

NODE TABLE ABBREVIATIONS

Junction

OU

MANHOLE / NODE TYPE

Manhole

MANHOLE FUNCTION

CMJLHRF

Z

TFSC

Combined Sewer Overflow

SoakawayDual Function ManholeTreatment Works

V

PSD

W

SEWER SHAPE

Pumping Station

LampholeHatchboxRodding EyeOutfall

FoulSurfaceCombined

F

CircularEggOvalFlat Top

EO

C

Polyvinyl Chloride

Concrete Segments (Bolted)Concrete Segments (Unbolted)Concrete Box CulvertDuctile Iron

Glass Reinforced PlasticPlastic / Steel Composite

Unspecified

Pitch FibreMasonry - In Regular CoursesMasonry - Randomly Coursed

Glass Reinforced Concrete

PolytheneReinforced Plastic MatrixSteelVitrified Clay (All Clayware)Polypropylene

Asbestos Cement

Spun (Grey) IronConcrete

SEWER MATERIAL

BrickACBR

Cast IronCISICOCSCSCC

RectangularSquare

RS

PE

DIGRGRPSPV

RP

VCST

PPPFMAMAU

This plan is based upon the Ordnance Survey mapwith the sanction of the Controller of H.M.Stationary Office.Unauthorised reproduction infringes copyright.Crown Copyright preserved.

Note - ALL flow direction arrows are BLUE - colour not significant

OS Sheet No: SD8721NEScale 1:1250 Date: 26-Oct-2011

OS Sheet No: SD8721NEScale 1:1250 Date: 26-Oct-2011

50 NodesSheet 1 of 1

370

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297.0m

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324

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5

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3

287.0m

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Works

139137

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345

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305

293

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254

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276

268

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8

Parklands

182

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180

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298.5m

15

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216

277.5m

273.2m

202

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186

204

200

(disused)

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14

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CA

COTMAN CLOSE

26

29

28

15

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FARRINGTON

24

18

9

16

811

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282a

3233

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29

3031

3637

39

40

234678

38

2627

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148147

145144

146

143141139

138

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NEW LINE (JONES) SITE MF

16

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130

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132

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168

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98

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100

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103

101

102

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117

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116

118

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71

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74

76

77

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65

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54

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910

2324

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156

159

165184

166

163162

154155

160

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111

172

169

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171

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Printed by: Angela Gall

23.09

5750.834.0137

53.7627.5184.12

CC VC 11

VC 15C VC 56

VCC VC 10C 10

VCVCC 62

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C VCC VC 26

300

300225150300300

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C MC M 291.65

293.52

S MS M 290.15

286.75

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MC M 284.26

M 285.24285.72

296.919701 296.75 C M9702 S M 295.34

294.989605 289.529606

291.53287.49603

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9601 287.439602 288.68

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92.1470.0392.66

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CC VC 77

VC 71C 71

CC VC 82

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C MS M 296.67

S MC M 279.36

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95019502 288.029503

298.148602 285.868701

284.117702 299.578601

7601 281.097701 299.22

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38.0183.8752.15199.22

96.43

36.6226.2625.3530.16

VCC VC 19C 42

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F M10.42

41.1444.7414.09

23.03

21.49

22 61.1525.94

9.5232.03

C COC VC

VC

CO

VCC VCC

C VCC VCC

GradSize.xSize.y ShapeMatl Length

M

MM 150

10501050

271.13

Func Type Invert

C M 375150150

M5703 F M5704 F

S5702 S M

5601 273.825602 F M

F5603 F56045701

Refno Cover


APPENDIX E Rossendale SFRA Maps


APPENDIX F Environment Agency Correspondence

1

Donna Metcalf

From: Ruckledge, John [[email protected]]Sent: 27 October 2011 16:14To: Luke MartinSubject: RE: New Line, BacupAttachments: New Line.jpg

Luke, The attached plan is the last we were consulted on in relation to planning applications. In order to be acceptable from a flood risk viewpoint, the section of culvert in 137/139 New Line needs to be diverted as it is inadequate. This is noted on the drawing. Initial works on site culverted part of the warecourse without our consent and raised land levels thereby potentially increasing the risk to the existing semis. We issued a Flood Defence Consent for the culvert diversion in 2007 but it was not carried out. This will be needed addressed by any developer. There was also an agreement to provide an attenutation pond for surface water partly for mitigation of loss of open watercourse due to the culverting. We would recommend that any revised layouts have at least 3m easement to each side of the culvert for future access. At the time, Michael Lambert Associates looked at the flood risk associated with the site and will be familiar with the site. If you want to discuss with him, his Email is:- [email protected] Happy to disuss further if you wish. John Ruckledge| Development & Flood Risk Team East |

Environment Agency | 01925 543410 | Fax 01925 852260 |

Appleton House, 430 Birchwood Boulevard, Birchwood, Warrington, WA3 7WD

From: Luke Martin [mailto:[email protected]] Sent: 27 October 2011 15:22 To: Ruckledge, John Subject: New Line, Bacup

Click here to report this email as spam.

Hi John, Further to our recent telephone conversation regarding the above development, if you could provide any information and requirements outlined historically it would be much appreciated. Unfortunately, we have very little information so if you could specify easement widths to the stream and confirm if the stream can be left in its current position/ condition I’d appreciate it. Thank you Best Regards Luke Martin Design Engineer

2

Harron Homes Ltd. Tel: (0113) 204 4670 Fax: (0113) 204 4677 Email: [email protected] Web: www.harronhomes.co.uk

Please consider the environment before printing this email. The information in this email is intended only for the named recipient and may be privileged or confidential. If you are not the intended recipient please notify us immediately and do not copy, distribute or take action based on this email. If this email is marked 'personal' Harron Homes Ltd. is not liable in any way for its content. E-mails are susceptible to alteration. Harron Homes Ltd. shall not be liable for the message if altered, changed or falsified. Harron Homes Ltd. is registered in England and Wales no. 03012678, Registered Office: Colton House, Temple Point, Bullerthorpe Lane, Leeds, LS15 9JL. For more information about Harron Homes and the locations of our current developments please see www.harronhomes.co.uk.

1

Donna Metcalf

From: Ruckledge, John [[email protected]]Sent: 03 November 2011 14:23To: [email protected]: New Line, Bacup

FAO Donna Metcalf Further to our earlier conversation I looked into our file records for the site. As it was not possible to determine existing discharge rates from the previous development on the site, surface water run-off should be limited to 13 litres/sec/ha. The previous design submitted for planning was based on a 15 l/s discharge rate from the attenuation pond. The pond was provided in mitigation for the loss of open channel across the site. The short culvert diversion that is required is to reduce flood risk to the existing semi detached properties. Risk to these in the event of culvert blockage was increased due to the site levels being raised. Happy to discuss further if you wish.

John Ruckledge| Development & Flood Risk Team East |

Environment Agency | 01925 543410 | Fax 01925 852260 |

Appleton House, 430 Birchwood Boulevard, Birchwood, Warrington, WA3 7WD

Information in this message may be confidential and may be legally privileged. If you have received this message by mistake, please notify the sender immediately, delete it and do not copy it to anyone else. We have checked this email and its attachments for viruses. But you should still check any attachment before opening it. We may have to make this message and any reply to it public if asked to under the Freedom of Information Act, Data Protection Act or for litigation. Email messages and attachments sent to or from any Environment Agency address may also be accessed by someone other than the sender or recipient, for business purposes. If we have sent you information and you wish to use it please read our terms and conditions which you can get by calling us on 08708 506 506. Find out more about the Environment Agency at www.environment-agency.gov.uk


APPENDIX G IOH124 Calculation

INSTITUTE OF HYDROLOGY REPORT 124 FLOOD ESTIMATION ON SMALL CATCHMENTS

Key

User InputHeader (do not change)Formula cell (do not change)

Step 1: Enter catchment descriptors and calculate QBARAREA From FEH CD-ROM 0.61 km2SAAR4170 From FEH CD-ROM 1457 mmSOIL From FSR WRAP maps 0.322 Enter fraction of catchment covered by each WRAP class:

1 2 3 4 5 1

QBAR 0.299 m3/s

Step 2: Use a FSR regional growth curve to estimate design flows

10

Return period Design flow (m3/s) Specific runoff (l/s/ha)

This spreadsheet is suitable for estimating design flows on small rural catchments (less than 25 km 2 ) using the IH Report 124 equation for QBAR plus the FSR regional growth curves. Rural can be taken as meaning URBAN less than 0.05, or equivalently URBEX

Choose your region from the map. Enter a number, or I for Ireland or GB for Great Britain

runoff (l/s/ha)

2 0.278 4.552.33 0.292 4.78

5 0.356 5.8310 0.413 6.7620 0.471 7.7325 0.491 8.0530 0.507 8.3150 0.554 9.0875 0.593 9.71

100 0.621 10.18150 0.662 10.86200 0.693 11.35

VERSION FEH CD‐ROM Version 3 exported at 07:25:57 GMT Fri 04‐Nov‐11CATCHMENGB 388050 421650 SD 88050 21650CENTROID GB 388463 422198 SD 88463 22198AREA 0.61 URBCONC1990 ‐999999ALTBAR 356 URBEXT1990 0.0041ASPBAR 228 URBLOC1990 ‐999999ASPVAR 0.79 URBCONC2000 0.286BFIHOST 0.496 URBEXT2000 0.0152DPLBAR 0.81 URBLOC2000 0.176DPSBAR 120.6 C ‐0.026FARL 1 D1 0.40028FPEXT 0.0041 D2 0.3952FPDBAR 0.033 D3 0.43091FPLOC ‐999999 E 0.30711LDP 1.44 F 2.53518PROPWET 0.57 C(1 km) ‐0.026RMED‐1H 11.8 D1(1 km) 0.4RMED‐1D 45.5 D2(1 km) 0.398RMED‐2D 61.4 D3(1 km) 0.435SAAR 1457 E(1 km) 0.307SAAR4170 1518 F(1 km) 2.532SPRHOST 32.22


APPENDIX H Manning’s Equation:

Channel Capacity Calculations


APPENDIX I Colebrook‐White: Culvert Capacity

Calculations

Roughness 0.6 mm U/S level 280.814 mDiam(mm) 1600 mm D/S level 280.798 mLength 30.2 m Gradient 0.0005298 1887.5__________ __________ __________ __________ __________ __________ __________ ________PROPOR'N WETTED AREA OF HYDRAULIC VELOCITY DISCHARGE DEPTH SURFACE DEPTH PERIMETER FLOW MEAN DEPTH (m/s) (l/s) (mm) WIDTH__________ __________ __________ __________ __________ __________ __________ _(mm)__

FULL 5.02654825 2.010619298 0.4000000 1.01 2,036.76 1600

0.01 0.32053575 0.003403075 0.0106168 0.09 0.30 16 3180.02 0.45407057 0.00959623 0.0211338 0.15 1.41 32 4480.03 0.55706563 0.017575709 0.0315505 0.20 3.43 48 5460.04 0.64434535 0.026976609 0.0418667 0.24 6.39 64 6270.05 0.7216429 0.03758458 0.0520820 0.27 10.30 80 6970.1 1.02960177 0.10464071 0.1016322 0.43 44.58 160 960

0.15 1.27263813 0.189119258 0.1486041 0.54 102.88 240 1,1430.2 1.48367235 0.28626894 0.1929462 0.64 183.78 320 1,280

0.25 1.67551608 0.393078304 0.2346013 0.73 285.77 400 1,3860.3 1.85484717 0.507310992 0.2735055 0.80 405.85 480 1,466

0.35 2.02576588 0.627150024 0.3095866 0.86 541.86 560 1,5260.4 2.19110145 0.751026705 0.3427622 0.92 691.70 640 1,568

0.45 2.35300625 0.877523304 0.3729371 0.97 851.20 720 1,5920.5 2.51327412 1.005309649 0.4000000 1.01 1,018.38 800 1,600

0.55 2.673542 1.133095995 0.4238183 1.05 1,189.75 880 1,5920.6 2.8354468 1.259592593 0.4442307 1.08 1,361.62 960 1,568

0.65 3.00078237 1.383469274 0.4610362 1.11 1,530.12 1040 1,5260.7 3.17170108 1.503308306 0.4739754 1.13 1,691.22 1120 1,466

0.75 3.35103216 1.617540995 0.4826993 1.14 1,840.76 1200 1,3860.8 3.5428759 1.724350359 0.4867092 1.14 1,972.66 1280 1,280

0.85 3.75391012 1.821500041 0.4852274 1.14 2,078.33 1360 1,1430.9 3.99694647 1.905978589 0.4768587 1.13 2,151.85 1440 960

0.95 4.30490535 1.973034718 0.4583224 1.10 2,174.28 1520 6971 5.02654825 2.010619298 0.4000000 1.01 2,036.76 1600 0

COLEBROOK WHITE: EXISTING 1.6m DIAMETER CULVERT


FULL 5.81194641 2.688025214 0.4625000 3.45 9,265.62 1850

0.01 0.37061946 0.004549619 0.0122757 0.33 1.50 19 3680.02 0.5250191 0.012829335 0.0244359 0.53 6.79 37 5180.03 0.64410714 0.023497213 0.0364803 0.69 16.26 56 6310.04 0.74502431 0.036065408 0.0484084 0.83 30.04 74 7250.05 0.8343996 0.050247354 0.0602198 0.96 48.24 93 8060.1 1.19047705 0.139895636 0.1175122 1.47 206.07 185 1,110

0.15 1.47148784 0.252836195 0.1718235 1.87 473.06 278 1,3210.2 1.71549615 0.382716971 0.2230940 2.20 842.36 370 1,480

0.25 1.93731547 0.525511912 0.2712578 2.48 1,305.37 463 1,6020.3 2.14466704 0.678231199 0.3162408 2.73 1,852.25 555 1,696

0.35 2.34229179 0.838445686 0.3579595 2.95 2,470.90 648 1,7650.4 2.53346105 1.004058163 0.3963188 3.14 3,149.73 740 1,813

0.45 2.72066348 1.173173245 0.4312085 3.30 3,874.99 833 1,8410.5 2.9059732 1.344012607 0.4625000 3.45 4,632.81 925 1,850

0.55 3.09128293 1.514851969 0.4900399 3.57 5,409.54 1018 1,8410.6 3.27848536 1.683967051 0.5136418 3.68 6,188.58 1110 1,813

0.65 3.46965461 1.849579528 0.5330731 3.76 6,952.57 1203 1,7650.7 3.66727937 2.009794015 0.5480341 3.82 7,683.44 1295 1,696

0.75 3.87463094 2.162513303 0.5581211 3.87 8,358.11 1388 1,6020.8 4.09645026 2.305308243 0.5627575 3.89 8,956.12 1480 1,480

0.85 4.34045857 2.435189019 0.5610442 3.88 9,443.66 1573 1,3210.9 4.62146936 2.548129578 0.5513678 3.84 9,777.17 1665 1,110

0.95 4.97754681 2.63777786 0.5299353 3.75 9,878.48 1758 8061 5.81194641 2.688025214 0.4625000 3.45 9,265.62 1850 0

COLEBROOK WHITE: EXISTING 1.85m DIAMETER CULVERT


FULL 4.08407045 1.327322896 0.3250000 2.78 3,685.98 1300

0.01 0.2604353 0.002246561 0.0086262 0.26 0.58 13 2590.02 0.36893234 0.006335011 0.0171712 0.42 2.64 26 3640.03 0.45261583 0.011602714 0.0256348 0.55 6.35 39 4440.04 0.52353059 0.017808777 0.0340167 0.66 11.77 52 5090.05 0.58633486 0.024811696 0.0423166 0.76 18.93 65 5670.1 0.83655144 0.069079218 0.0825762 1.18 81.31 130 780

0.15 1.03401848 0.12484826 0.1207408 1.50 187.15 195 9280.2 1.20548378 0.18898223 0.1567688 1.77 333.74 260 1,040

0.25 1.36135682 0.259493099 0.1906136 2.00 517.95 325 1,1260.3 1.50706332 0.334904522 0.2222233 2.20 735.45 390 1,191

0.35 1.64593477 0.414017008 0.2515391 2.37 981.63 455 1,2400.4 1.78026993 0.495794973 0.2784943 2.53 1,251.88 520 1,274

0.45 1.91181758 0.579302493 0.3030114 2.66 1,540.94 585 1,2930.5 2.04203522 0.663661448 0.3250000 2.78 1,842.99 650 1,300

0.55 2.17225287 0.748020403 0.3443524 2.88 2,152.80 715 1,2930.6 2.30380052 0.831527923 0.3609375 2.96 2,462.99 780 1,274

0.65 2.43813568 0.913305888 0.3745919 3.03 2,767.32 845 1,2400.7 2.57700712 0.992418374 0.3851050 3.08 3,058.63 910 1,191

0.75 2.72271363 1.067829797 0.3921932 3.12 3,328.43 975 1,1260.8 2.87858667 1.138340667 0.3954512 3.13 3,566.42 1040 1,040

0.85 3.05005197 1.202474636 0.3942473 3.13 3,760.14 1105 9280.9 3.24751901 1.258243678 0.3874477 3.09 3,893.01 1170 780

0.95 3.49773559 1.3025112 0.3723870 3.02 3,932.28 1235 5671 4.08407045 1.327322896 0.3250000 2.78 3,685.98 1300 0

COLEBROOK WHITE: EXISTING 1.85m DIAMETER CULVERT - 50% blockage


APPENDIX J HY‐8 Culvert Analysis Calculations

HY-8 Culvert Analysis Report

Project Notes

Project Units: SI Units (Metric)

Outlet Control Option: Profiles

Exit Loss Option: Standard Method

Crossing Notes: Wall Opening

Donna Metcalf

Text Box

New Line, Bacup

Donna Metcalf

Text Box

Free discharge through opening into open channel and subsequently 1.85m diameter concrete culvert.

HY-8 Analysis Results

Crossing Summary Table

Culvert Crossing: Wall Opening

Headwater Elevation (m)

Total Discharge (cms) Wall Opening Discharge (cms)

Roadway Discharge (cms)

Iterations

280.99 0.10 0.10 0.00 1

281.15 0.39 0.39 0.00 1

281.27 0.68 0.68 0.00 1

281.32 0.81 0.81 0.00 1

281.61 1.26 1.26 0.00 1

281.72 1.55 1.55 0.00 1

281.80 1.84 1.84 0.00 1

281.95 2.13 2.13 0.00 1

282.09 2.42 2.42 0.00 1

282.25 2.71 2.71 0.00 1

282.41 3.00 3.00 0.00 1

282.52 3.17 3.17 0.00 Overtopping

Donna Metcalf

Highlight

Rating Curve Plot for Crossing: Wall Opening

Culvert Notes: Wall Opening


Culvert Summary Table - Wall Opening


Total Discharge (cms)

Culvert Discharge (cms)


Inlet Control Depth(m)

Outlet Control Depth(m)

Flow Type

Normal Depth (m)

Critical Depth (m)

Outlet Depth (m)

Tailwater Depth (m)

Outlet Velocity (m/s)

Tailwater Velocity (m/s)

0.10 0.10 280.99 0.13 0.0* 1-S2n 0.04 0.09 0.04 0.16 1.51 0.26

0.39 0.39 281.15 0.29 0.0* 1-S2n 0.10 0.21 0.15 0.35 2.08 0.42

0.68 0.68 281.27 0.41 0.0* 1-S2n 0.14 0.30 0.22 0.47 2.36 0.50

0.81 0.81 281.32 0.46 0.0* 1-S2n 0.15 0.33 0.24 0.52 2.46 0.52

1.26 1.26 281.61 0.62 0.75 1-S1t 0.19 0.44 0.64 0.66 1.40 0.60

1.55 1.55 281.72 0.72 0.86 5-S1t 0.22 0.51 0.72 0.74 1.52 0.64

1.84 1.84 281.80 0.84 0.94 4-FFf 0.24 0.56 0.77 0.82 1.69 0.67

2.13 2.13 281.95 0.97 1.09 4-FFf 0.26 0.62 0.77 0.88 1.96 0.70

2.42 2.42 282.09 1.11 1.23 4-FFf 0.28 0.67 0.77 0.94 2.22 0.72

2.71 2.71 282.25 1.26 1.39 4-FFf 0.30 0.73 0.77 1.00 2.49 0.75

3.00 3.00 282.41 1.44 1.55 4-FFf 0.31 0.77 0.77 1.06 2.76 0.77

Donna Metcalf

Highlight

* theoretical depth is impractical. Depth reported is corrected.

Culvert Performance Curve Plot: Wall Opening

Water Surface Profile Plot for Culvert: Wall Opening

Site Data - Wall Opening

Site Data Option: Culvert Invert Data

Inlet Station: 0.00 m

Inlet Elevation: 280.86 m

Outlet Station: 2.00 m

Outlet Elevation: 280.79 m

Number of Barrels: 1

Culvert Data Summary - Wall Opening

Barrel Shape: User Defined

Barrel Span: 1450.00 mm

Barrel Rise: 768.00 mm

Barrel Material: Concrete

Embedment: 0.00 mm

Barrel Manning's n: 0.0120 (top and sides)

Manning's n: 0.0700 (bottom)

Inlet Type: Conventional

Inlet Edge Condition: Square Edge with Headwall

Inlet Depression: NONE

Tailwater Channel Data - Wall Opening

Tailwater Channel Option: Irregular Channel

Tailwater Rating Curve Plot for Crossing: Wall Opening

Roadway Data for Crossing: Wall Opening

Roadway Profile Shape: Constant Roadway Elevation

Crest Length: 6.90 m

Crest Elevation: 282.52 m

Roadway Surface: Gravel

Roadway Top Width: 2.00 m

HY-8 Culvert Analysis Report

Project Notes

Project Units: SI Units (Metric)

Outlet Control Option: Profiles

Exit Loss Option: Standard Method

Crossing Notes: Wall Opening

donnametcalf

Text Box

New Line, Bacup

donnametcalf

Text Box

50% blockage applied to opening into channel


Crossing Summary Table



Total Discharge (cms) Wall Opening Discharge (cms)

Roadway Discharge (cms)

Iterations

281.00 0.10 0.10 0.00 1

281.21 0.39 0.39 0.00 1

281.40 0.68 0.68 0.00 1

281.51 0.81 0.81 0.00 1

281.98 1.26 1.26 0.00 1

282.34 1.55 1.55 0.00 1

282.58 1.84 1.69 0.14 6

282.64 2.13 1.69 0.44 6

282.69 2.42 1.68 0.74 5

282.73 2.71 1.67 1.04 5

282.77 3.00 1.65 1.35 5

282.52 1.68 1.68 0.00 Overtopping

Donna Metcalf

Highlight

Rating Curve Plot for Crossing: Wall Opening

Culvert Notes: Wall Opening


Culvert Summary Table - Wall Opening


Total Discharge (cms)

Culvert Discharge (cms)


Inlet Control Depth(m)

Outlet Control Depth(m)

Flow Type

Normal Depth (m)

Critical Depth (m)

Outlet Depth (m)

Tailwater Depth (m)

Outlet Velocity (m/s)

Tailwater Velocity (m/s)

0.10 0.10 281.00 0.11 0.14 0-M1t 0.11 0.08 0.14 0.16 0.49 0.26

0.39 0.39 281.21 0.28 0.35 0-M1t 0.25 0.19 0.32 0.35 0.83 0.42

0.68 0.68 281.40 0.43 0.54 1-FFf 0.35 0.28 0.39 0.47 1.19 0.50

0.81 0.81 281.51 0.50 0.65 1-FFf 0.39 0.32 0.39 0.52 1.42 0.52

1.26 1.26 281.98 0.86 1.12 1-FFf 0.39 0.39 0.39 0.66 2.21 0.60

1.55 1.55 282.34 1.17 1.48 1-FFf 0.39 0.39 0.39 0.74 2.71 0.64

1.84 1.69 282.58 1.36 1.72 1-FFf 0.39 0.39 0.39 0.82 2.97 0.67

2.13 1.69 282.64 1.35 1.78 1-FFf 0.39 0.39 0.39 0.88 2.96 0.70

2.42 1.68 282.69 1.34 1.83 1-FFf 0.39 0.39 0.39 0.94 2.94 0.72

2.71 1.67 282.73 1.32 1.88 1-FFf 0.39 0.39 0.39 1.00 2.92 0.75

3.00 1.65 282.77 1.30 1.91 1-FFf 0.39 0.39 0.39 1.06 2.89 0.77

Donna Metcalf

Highlight

Culvert Performance Curve Plot: Wall Opening

Water Surface Profile Plot for Culvert: Wall Opening

Site Data - Wall Opening

Site Data Option: Culvert Invert Data

Inlet Station: 0.00 m

Inlet Elevation: 280.86 m

Outlet Station: 2.00 m

Outlet Elevation: 280.79 m

Number of Barrels: 1

Culvert Data Summary - Wall Opening

Barrel Shape: User Defined

Barrel Span: 1450.00 mm

Barrel Rise: 394.00 mm

Barrel Material: Concrete

Embedment: 0.00 mm

Barrel Manning's n: 0.0120 (top and sides)

Manning's n: 0.0700 (bottom)

Inlet Type: Conventional

Inlet Edge Condition: Square Edge with Headwall

Inlet Depression: NONE

Tailwater Channel Data - Wall Opening

Tailwater Channel Option: Irregular Channel

Tailwater Rating Curve Plot for Crossing: Wall Opening

Roadway Data for Crossing: Wall Opening

Roadway Profile Shape: Constant Roadway Elevation

Crest Length: 6.90 m

Crest Elevation: 282.52 m

Roadway Surface: Gravel

Roadway Top Width: 2.00 m


APPENDIX K Indicative Attenuation Volume

Calculations

Modified Rational Method Return Period flood 2 yearsPost Development Rainfall 2 years

Length (m) 120 m

Area (ha) 0.520 Ha FLOW (m3) RAIN (m3)Max Height 288.5 mAOD 0.25 0.010 7.76 8.2 31.0 47.5 91.4 43 43 13.50 29Min Height 284.0 mAOD 0.5 0.021 10.31 10.9 20.6 31.6 60.7 57 57 27.00 30DeltaH 4.5 0.75 0.031 12.16 12.9 16.2 24.8 47.7 67 67 40.50 26Slope (%) 3.75 1 0.042 13.66 14.5 13.7 20.9 40.2 75 75 54.00 21Te (mins) 9.79 mins 1.25 0.052 14.94 15.8 12.0 18.3 35.2 82 82 67.50 15ARF 0.998 1.5 0.063 16.08 17.0 10.7 16.4 31.6 89 89 81.00 8SAAR 1457.000 mm 1.75 0.073 17.1 18.1 9.8 15.0 28.8 94 94 94.50 0UCWI 144 mm 2 0.083 18.04 19.1 9.0 13.8 26.6 99 99 108.00 ‐9PIMP 100.0 % 2.25 0.094 18.91 20.0 8.4 12.9 24.7 104 104 121.50 ‐17SOIL 0.32 2.5 0.104 19.72 20.9 7.9 12.1 23.2 109 109 135.00 ‐26Percentage Runoff PR 81.48 2.75 0.115 20.49 21.7 7.5 11.4 21.9 113 113 148.50 ‐36DEEPSTOR 0.38 3 0.125 21.21 22.5 7.1 10.8 20.8 117 117 162.00 ‐45

3.25 0.135 21.9 23.2 6.7 10.3 19.8 121 121 175.50 ‐553.5 0.146 22.56 23.9 6.4 9.9 19.0 124 124 189.00 ‐65

Cv 0.81482 3.75 0.156 23.19 24.6 6.2 9.5 18.2 128 128 202.50 ‐75Cr 1.3 4 0.167 23.79 25.2 5.9 9.1 17.5 131 131 216.00 ‐85allowable outflow 4.25 0.177 24.37 25.8 5.7 8.8 16.9 134 134 229.50 ‐952 year 0.015 m3s 4.5 0.188 24.93 26.4 5.5 8.5 16.3 137 137 243.00 ‐106

m3 4.75 0.198 25.48 27.0 5.4 8.2 15.8 140 140 256.50 ‐116

Storage RT years Storage 5 0.208 26 27.5 5.2 8.0 15.3 143 143 270.00 ‐1272 30 5.25 0.219 26.51 28.1 5.0 7.7 14.9 146 146 283.50 ‐137

5.5 0.229 27 28.6 4.9 7.5 14.5 149 149 297.00 ‐1485.75 0.240 27.49 29.1 4.8 7.3 14.1 152 151 310.50 ‐1596 0.250 27.95 29.6 4.7 7.1 13.7 154 154 324.00 ‐170

6.25 0.260 28.41 30.1 4.5 7.0 13.4 157 156 337.50 ‐1816.5 0.271 28.86 30.6 4.4 6.8 13.1 159 159 351.00 ‐1926.75 0.281 29.29 31.0 4.3 6.6 12.8 161 161 364.50 ‐2037 0.292 29.72 31.5 4.2 6.5 12.5 164 164 378.00 ‐214

Rainfall Duration (hours)

Rainfall Duration (days)

Rainfall Depth (mm)

Effective Depth (mm)

Allowable

Outflow (m3)Difference (m3)

Rainfall Intensity (mm/hr)

FLOW (l/s) FLOW (l/s/ha)RUN‐OFF


Length (m) 120 m

Area (ha) 0.520 Ha FLOW (m3) RAIN (m3)Max Height 288.5 mAOD 0.25 0.010 26.12 27.7 104.5 160.0 307.7 144 144 13.50 130Min Height 284.0 mAOD 0.5 0.021 32.55 34.5 65.1 99.7 191.7 179 179 27.00 152DeltaH 4.5 0.75 0.031 36.97 39.2 49.3 75.5 145.2 204 204 40.50 163Slope (%) 3.75 1 0.042 40.44 42.8 40.4 61.9 119.1 223 223 54.00 169Te (mins) 9.79 mins 1.25 0.052 43.35 45.9 34.7 53.1 102.1 239 239 67.50 171ARF 0.998 1.5 0.063 45.87 48.6 30.6 46.8 90.1 253 253 81.00 172SAAR 1457.000 mm 1.75 0.073 48.11 51.0 27.5 42.1 81.0 265 265 94.50 170UCWI 144 mm 2 0.083 50.13 53.1 25.1 38.4 73.8 276 276 108.00 168PIMP 100.0 % 2.25 0.094 51.99 55.1 23.1 35.4 68.0 287 286 121.50 165SOIL 0.32 2.5 0.104 53.7 56.9 21.5 32.9 63.3 296 296 135.00 161Percentage Runoff PR 81.48 2.75 0.115 55.3 58.6 20.1 30.8 59.2 305 305 148.50 156DEEPSTOR 0.38 3 0.125 56.8 60.2 18.9 29.0 55.8 313 313 162.00 151

3.25 0.135 58.21 61.7 17.9 27.4 52.7 321 321 175.50 1453.5 0.146 59.55 63.1 17.0 26.1 50.1 328 328 189.00 139

Cv 0.81482 3.75 0.156 60.82 64.4 16.2 24.8 47.8 335 335 202.50 133Cr 1.3 4 0.167 62.03 65.7 15.5 23.7 45.7 342 342 216.00 126allowable outflow 4.25 0.177 63.2 66.9 14.9 22.8 43.8 348 348 229.50 11930 year 0.015 m3s 4.5 0.188 64.31 68.1 14.3 21.9 42.1 355 354 243.00 111

m3 4.75 0.198 65.38 69.3 13.8 21.1 40.5 360 360 256.50 104

Storage RT years Storage 5 0.208 66.42 70.4 13.3 20.3 39.1 366 366 270.00 9630 172 5.25 0.219 67.42 71.4 12.8 19.7 37.8 372 371 283.50 88

5.5 0.229 68.38 72.4 12.4 19.0 36.6 377 377 297.00 805.75 0.240 69.31 73.4 12.1 18.5 35.5 382 382 310.50 716 0.250 70.22 74.4 11.7 17.9 34.5 387 387 324.00 63

6.25 0.260 71.1 75.3 11.4 17.4 33.5 392 392 337.50 546.5 0.271 71.96 76.2 11.1 17.0 32.6 397 396 351.00 456.75 0.281 72.79 77.1 10.8 16.5 31.8 401 401 364.50 367 0.292 73.6 78.0 10.5 16.1 31.0 406 405 378.00 27



Rainfall Depth (mm)


Allowable





Length (m) 120 m

Area (ha) 0.520 Ha FLOW (m3) RAIN (m3)Max Height 288.5 mAOD 0.25 0.010 37.28 39.5 149.1 228.3 439.1 206 205 13.50 192Min Height 284.0 mAOD 0.5 0.021 45.59 48.3 91.2 139.6 268.5 251 251 27.00 224DeltaH 4.5 0.75 0.031 51.22 54.3 68.3 104.6 201.1 282 282 40.50 242Slope (%) 3.75 1 0.042 55.6 58.9 55.6 85.1 163.7 306 306 54.00 252Te (mins) 9.79 mins 1.25 0.052 59.23 62.7 47.4 72.6 139.5 327 326 67.50 259ARF 0.998 1.5 0.063 62.37 66.1 41.6 63.7 122.4 344 344 81.00 263SAAR 1457.000 mm 1.75 0.073 65.14 69.0 37.2 57.0 109.6 359 359 94.50 264UCWI 144 mm 2 0.083 67.64 71.6 33.8 51.8 99.6 373 373 108.00 265PIMP 100.0 % 2.25 0.094 69.92 74.1 31.1 47.6 91.5 385 385 121.50 264SOIL 0.32 2.5 0.104 72.02 76.3 28.8 44.1 84.8 397 397 135.00 262Percentage Runoff PR 81.48 2.75 0.115 73.97 78.4 26.9 41.2 79.2 408 407 148.50 259DEEPSTOR 0.38 3 0.125 75.8 80.3 25.3 38.7 74.4 418 418 162.00 256

3.25 0.135 77.52 82.1 23.9 36.5 70.2 427 427 175.50 2513.5 0.146 79.14 83.8 22.6 34.6 66.6 436 436 189.00 247

Cv 0.81482 3.75 0.156 80.68 85.5 21.5 32.9 63.4 445 444 202.50 242Cr 1.3 4 0.167 82.15 87.0 20.5 31.4 60.5 453 452 216.00 236allowable outflow 4.25 0.177 83.55 88.5 19.7 30.1 57.9 461 460 229.50 231100 year 0.015 m3s 4.5 0.188 84.9 89.9 18.9 28.9 55.6 468 468 243.00 225

m3 4.75 0.198 86.19 91.3 18.1 27.8 53.4 475 475 256.50 218

Storage RT years Storage 5 0.208 87.43 92.6 17.5 26.8 51.5 482 482 270.00 212100 265 5.25 0.219 88.62 93.9 16.9 25.8 49.7 489 488 283.50 205

5.5 0.229 89.78 95.1 16.3 25.0 48.1 495 495 297.00 1985.75 0.240 90.9 96.3 15.8 24.2 46.6 501 501 310.50 1906 0.250 91.98 97.4 15.3 23.5 45.1 507 507 324.00 183

6.25 0.260 93.03 98.5 14.9 22.8 43.8 513 512 337.50 1756.5 0.271 94.05 99.6 14.5 22.2 42.6 518 518 351.00 1676.75 0.281 95.04 100.7 14.1 21.6 41.5 524 523 364.50 1597 0.292 96.01 101.7 13.7 21.0 40.4 529 529 378.00 151



Rainfall Depth (mm)


Allowable




Modified Rational Method Return Period flood 100+cc yearsPost Development Rainfall 140 years

Length (m) 120 m

Area (ha) 0.520 Ha FLOW (m3) RAIN (m3)Max Height 288.5 mAOD 0.25 0.010 37.28 48.464 51.3 149.1 228.3 439.1 206 267 13.50 253Min Height 284.0 mAOD 0.5 0.021 45.59 59.267 62.8 91.2 139.6 268.5 251 326 27.00 299DeltaH 4.5 0.75 0.031 51.22 66.586 70.5 68.3 104.6 201.1 282 367 40.50 326Slope (%) 3.75 1 0.042 55.6 72.28 76.6 55.6 85.1 163.7 306 398 54.00 344Te (mins) 9.79 mins 1.25 0.052 59.23 76.999 81.6 47.4 72.6 139.5 327 424 67.50 357ARF 0.998 1.5 0.063 62.37 81.081 85.9 41.6 63.7 122.4 344 447 81.00 366SAAR 1457.000 mm 1.75 0.073 65.14 84.682 89.7 37.2 57.0 109.6 359 466 94.50 372UCWI 144 mm 2 0.083 67.64 87.932 93.1 33.8 51.8 99.6 373 484 108.00 376PIMP 100.0 % 2.25 0.094 69.92 90.896 96.3 31.1 47.6 91.5 385 501 121.50 379SOIL 0.32 2.5 0.104 72.02 93.626 99.2 28.8 44.1 84.8 397 516 135.00 381Percentage Runoff PR 81.48 2.75 0.115 73.97 96.161 101.9 26.9 41.2 79.2 408 530 148.50 381DEEPSTOR 0.38 3 0.125 75.8 98.54 104.4 25.3 38.7 74.4 418 543 162.00 381

3.25 0.135 77.52 100.776 106.7 23.9 36.5 70.2 427 555 175.50 3803.5 0.146 79.14 102.882 109.0 22.6 34.6 66.6 436 567 189.00 378

Cv 0.81482 3.75 0.156 80.68 104.884 111.1 21.5 32.9 63.4 445 578 202.50 375Cr 1.3 4 0.167 82.15 106.795 113.1 20.5 31.4 60.5 453 588 216.00 372allowable outflow 4.25 0.177 83.55 108.615 115.1 19.7 30.1 57.9 461 598 229.50 369100 year 0.015 m3s 4.5 0.188 84.9 110.37 116.9 18.9 28.9 55.6 468 608 243.00 365

m3 4.75 0.198 86.19 112.047 118.7 18.1 27.8 53.4 475 617 256.50 361

Storage RT years Storage 5 0.208 87.43 113.659 120.4 17.5 26.8 51.5 482 626 270.00 356100 + cc 381 5.25 0.219 88.62 115.206 122.0 16.9 25.8 49.7 489 635 283.50 351

5.5 0.229 89.78 116.714 123.6 16.3 25.0 48.1 495 643 297.00 3465.75 0.240 90.9 118.17 125.2 15.8 24.2 46.6 501 651 310.50 3406 0.250 91.98 119.574 126.7 15.3 23.5 45.1 507 659 324.00 335

6.25 0.260 93.03 120.939 128.1 14.9 22.8 43.8 513 666 337.50 3296.5 0.271 94.05 122.265 129.5 14.5 22.2 42.6 518 673 351.00 3226.75 0.281 95.04 123.552 130.9 14.1 21.6 41.5 524 681 364.50 3167 0.292 96.01 124.813 132.2 13.7 21.0 40.4 529 687 378.00 309

30% increaseRainfall Duration

(hours)Rainfall Duration

(days)Rainfall Depth

(mm)Effective Depth

(mm)Allowable





APPENDIX L SUDs Suitability Matrix

Retention Pond Y Y Y¹ Y² Y² Y³ Y Y² Y Y¹ Y Y5 Y Y³ Y Y Y Y N Y M H * M H H M M M H L H H HSub-surface Storage Y Y Y Y Y Y³ Y Y Y Y Y Y5 Y Y Y Y Y Y Y Y L H * M L L L L L L L H H H

Shallow Wetland Y Y Y¹ Y² Y² N Y Y² Y² Y4 Y4 Y6 Y² Y² Y N Y Y N Y H H * H H H M H M H L H M LExtended Detention Wetland Y Y Y¹ Y² Y² N Y Y² Y² Y4 Y4 Y6 Y² Y² Y N Y Y N Y H H * H H H M H M H L H M LPond/ Wetland Y Y Y¹ Y² Y² N Y Y² Y² Y4 Y4 Y6 Y² Y² Y N Y Y N Y H H * H H H M H M H L H M LPocket Wetland Y Y Y¹ Y² Y² N Y Y² Y² Y4 Y4 N Y² Y² Y N Y Y Y Y H M * H H H M H M H L H M LSubmerged Gravel Wetland Y Y Y¹ Y² Y² N Y Y² Y² Y4 Y4 Y6 Y² Y² Y N Y Y N Y M L H M H M H M H L H M LWetland Channel Y Y Y¹ Y² Y² N Y Y² Y² Y4 Y4 Y6 Y² Y² Y N Y Y N Y H H * H H H M H M H L H M L

Infiltration Trench Y Y Y¹ Y² N N Y Y4 N Y Y N N Y Y Y Y N Y Y L M * L L H H H M H H H H LInfiltration Basin Y Y Y¹ Y² N N Y Y4 N Y Y Y5 N Y Y Y Y N N Y M H * L M H H H M H H H H HSoakaway Y Y Y¹ Y² N N Y Y4 N Y Y N N Y Y Y Y N Y Y L M M L H H H M H H H H L

Surface Sand Filter N Y Y¹ Y² Y² N Y Y² Y Y Y Y5 N Y Y N N Y N Y M L H M H H H M H L H M LSub surface Sand Filter N Y Y¹ Y² Y² N Y Y² Y Y Y N N Y Y N N Y Y Y M L H L H H H M H L H M L

Cap

acit

y to

tre

at F

ine

Su

spen

ded

Sed

imen

ts&

Dis

solv

ed P

oll

uta

nts

Water Quality Treatment Potential

Sui

tabi

lity

for

Flo

w R

ate

Con

trol

(p

roba

bilit

y)

0.1

- 0

.03

(10

/30y

r)

0.5

(1/

2yr)

Ru

no

ff

Vo

lum

e R

edu

ctio

n

Quantity & Quality Performances

Hydraulic Control

0.0

1 (

100

yr)

Nu

trie

nt

(Ph

osp

ho

rou

s,

Nit

rog

en)

Rem

ova

l

Bac

teri

a R

emo

val

( *

)

To

tal

Su

spen

ded

So

lid

s R

emo

val

Hea

vy M

etal

s R

emo

val

Matrix Selections

SUDS Group Technique

Res

iden

tial

Retention

Wetland

> 2

ha

Bro

wn

fiel

d

Co

nta

min

ated

Lan

d

Soi

l

Are

a D

rain

ing

to

Sin

gle

SU

DS

Com

pone

nt

Min

imum

dep

th t

o W

ater

Tab

le

Infiltration

Lo

w D

ensi

ty

Site Characteristics

Lo

cal

Ro

ads

Co

mm

erci

al

Ho

tsp

ots

Co

nst

ruct

ion

Sit

e

Land Use

0 –

1 m

Lo

w

Ava

ilabl

e H

ead

Ava

ilabl

e S

pace

1 –

2 m

Hig

h

0 –

1 m

0 –

2 h

a

Im

per

mea

ble

Per

mea

ble

SUDS SUITABILITY MATRIX ADAPTED FROM CIRIA REPORT C697 ‘THE MANUAL FOR SUDS’Community &Environmental

Mai

nte

nan

ce

Co

mm

un

ity

Acc

epta

bil

ity

Co

st

Hab

itat

Cre

atio

n P

ote

nti

al

> 1

m

Site

S

lope

0 –

5 %

> 5

%

Sub-surface Sand Filter N Y Y¹ Y² Y² N Y Y² Y Y Y N N Y Y N N Y Y Y M L H L H H H M H L H M LPerimeter Sand Filter N N Y¹ Y² Y² N Y Y² Y Y Y N N Y Y N Y Y Y Y M L H L H H H M H L H M LBioretention/ Filter Strip Y Y Y¹ Y² Y² N Y Y² Y Y Y N N Y Y N Y Y N Y H H M H H H H M H L H M LFilter Trench Y Y Y¹ Y² Y² N Y Y² Y Y¹ Y N N Y Y N Y Y Y Y M M M L H H H M H L H H L

Detention Detention Basin Y Y Y¹ Y² Y¹·² Y³ Y Y² Y Y¹ Y Y5 N Y Y Y N Y N Y L H * L M M M L L L L H H HConveyance Swale Y Y Y¹ Y² Y² Y³ Y Y² Y Y Y N N Y Y N³ Y N N Y L M * L M H M M M H M H H HEnhanced Dry Swale Y Y Y¹ Y² Y² Y³ Y Y² Y Y Y N N Y Y N³ Y N N Y L M * M M H H H M H M H H HEnhanced Wet Swale Y Y Y¹ Y² Y¹ Y³ Y Y² Y² Y4 Y N Y Y Y N³ Y N N Y M M * M H H H M H H L H H HGreen Roof Y Y N Y² Y N Y Y Y Y Y N Y Y Y Y Y Y Y Y H H H H n/a n/a n/a n/a H H H H LRain Water Harvesting Y Y N Y² N N Y Y Y Y Y N Y Y Y Y Y H M * H L M L L L n/a M M H LPermeable Pavements Y Y N Y² Y¹ N Y Y² Y Y Y Y N Y Y N Y Y Y Y M M M L H H H H H H H H L

* Limited Data Available

n/a: not applicable

H: High Potential M: Medium Potential L: Low Potential

Y:Yes N:No

1 May require two treatment train stages, depending on type and intensity of road use and receiving water sensitivity

2 May require three treatment rain stages, depending on receiving watercourse sensitivity

3 Will require draw-down rehabilitation following construction activities, prior to use as a permanent drainage system

4 providing designs prevent mobilisation of contamination

Filtration

Open Channels

Source Control

H: High M: Medium L: Low

* There may be some public safety concerns associated with open water that require address at design stage

Y:Yes N:No

1 With liner

2 With surface baseflow

3 Unless follows contours

4 With liner constant surface baseflow, or high ground water table

5 Possible, but not recommended (implies appropriate management train not in place)

6 Where high flows are diverted around SUDS component.


APPENDIX M Historical Borehole Logs

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APPENDIX N MicroDrainage Calculations

©1982-2009 Micro Drainage

Paul Waite Associates Page 1Summit House New Line BacupRiparian Way SW DrainageKeighley BD20 7BWDate 11 November 2011 Designed By DMFile surface water network.SWS Checked ByInfrasoft System1 W.11.4

STORM SEWER DESIGN by the Modified Rational Method

Network Design Table

PN

Length(m)

Fall(m)

Slope(1:X)

Area(ha)

T.E.(mins)

DWF(l/s)

k(mm)

HYDSECT

DIA(mm)

1.000 64.00 2.500 25.6 0.195 4.00 0.0 0.600 o 2251.001 16.00 0.750 21.3 0.212 0.00 0.0 0.600 o 2251.002 20.00 0.625 32.0 0.000 0.00 0.0 0.600 o 225

2.000 19.00 0.191 99.3 0.065 4.00 0.0 0.600 o 150

1.003 13.00 0.041 321.0 0.000 0.00 0.0 0.600 o 3751.004 13.00 0.041 321.0 0.000 0.00 0.0 0.600 o 3751.005 12.00 0.037 321.0 0.048 0.00 0.0 0.600 o 3751.006 10.00 0.031 321.0 0.000 0.00 0.0 0.600 o 375

Network Results Table

PN

Rain(mm/hr)

T.C.(mins)

US/IL(m)

E.Area(ha)

E.DWF(l/s)

Foul(l/s)

Add Flow(l/s)

Vel(m/s)

CAP(l/s)

Flow(l/s)

1.000 52.4 4.4 287.075 0.195 0.0 0.0 8.3 2.60 103.2 36.01.001 52.0 4.5 284.575 0.407 0.0 0.0 17.2 2.85 113.1 74.61.002 51.5 4.6 283.825 0.407 0.0 0.0 17.2 2.32 92.3 74.6

2.000 52.8 4.3 283.466 0.065 0.0 0.0 2.8 1.01 17.8 12.1

1.003 50.7 4.9 283.050 0.472 0.0 0.0 19.4 1.01 111.1 84.21.004 49.9 5.1 283.009 0.472 0.0 0.0 19.4 1.01 111.1 84.21.005 49.2 5.3 282.969 0.520 0.0 0.0 20.8 1.01 111.1 90.11.006 48.7 5.4 282.931 0.520 0.0 0.0 20.8 1.01 111.1 90.1


Paul Waite Associates Page 2Summit House New Line BacupRiparian Way SW DrainageKeighley BD20 7BWDate 11 November 2011 Designed By DMFile surface water network.SWS Checked ByInfrasoft System1 W.11.4

MANHOLE SCHEDULES

M/HoleNumber

CoverLevel(m)

M/HoleDepth(m)

M/HoleDiam.,L*W

(mm)PN

Pipes OutIL.(m) D (mm) PN

Pipes InIL.(m) D (mm)

1 288.500 1.425 1050 1.000 287.075 225

2 286.000 1.425 1050 1.001 284.575 225 1.000 284.575 225

3 285.250 1.425 1050 1.002 283.825 225 1.001 283.825 225

4 284.500 1.034 1050 2.000 283.466 150

5 284.600 1.550 1350 1.003 283.050 375 1.002 283.200 2252.000 283.275 150

6 284.600 1.591 1350 1.004 283.009 375 1.003 283.009 375

7 284.000 1.031 1350 1.005 282.969 375 1.004 282.969 375

8 284.000 1.069 1350 1.006 282.931 375 1.005 282.931 375

0.000 -282.900 0 OUTFALL 1.006 282.900 375


Paul Waite Associates Page 1Summit House New Line BacupRiparian Way SW DrainageKeighley BD20 7BWDate 11 November 2011 Designed By DMFile sw 30yr.SUM Checked ByInfrasoft Simulation W.11.4

Global Variables

Region FSR - England & WalesReturn Period (yrs) 2M5-60 (mm) 18.200Ratio R 0.250Volumetric Runoff Coef 0.750Profile Type SummerPIMP (%) 100Areal Reduction Factor 1.000Storm Duration (mins) 15Hot Start (mins) 0Hot Start Level (mm) 0Manhole Headloss Coefficient 0.500MADD Factor * 10m³/ha Storage 2.000Foul Sewage/Hectare (l/s) 0.00Additional Flow - % of Total Flow 30Inlet Coefficient 0.800Number of Input Hydrographs 0Number of Time/Area Diagrams 0Number of Bifurcations 0Number of Overflows 0Number of Off-Line Controls 0Number of On-Line Controls 0

Starting Storm file name F:\2011-023 New Line, Bacup\New folder (2)\surface water network.SWS

Freely Discharging Outfalls

OutfallPipe Number

OutfallMH/No

C.Level(m)

I.Level(m)

D,L(mm)

B(mm)

1.006 283.575 282.900 1200 0

Donna Metcalf

Highlight



Summary Wizard of "CRITICAL BY RETURN PERIOD"(Rank 1 by Max Level)Results for Design Storms

Margin for Flood Risk warning (mm) 50DTS Status ONDVD Status OFFInertia Status OFFAnalysis Time Step Fine

Profile(s) Summer and Winter

Duration(s) (mins)15, 30, 60, 120, 240, 360, 480, 960, 1440, 2160, 2880, 4320, 5760, 7200, 8640, 10080

Return Period(s) (years) 2, 30, 100Climate Change (%) 0, 0, 0

PN

Storm

ReturnPeriod

ClimateChange

Rank

First XSurcharge

First YFlood

First ZOverflow

O/FAct

1.000 15 Summer 2 0% 1 100/15 Summer1.001 15 Winter 2 0% 1 30/15 Summer 100/15 Summer1.002 15 Winter 2 0% 1 30/15 Summer2.000 15 Summer 2 0% 1 30/15 Summer1.003 15 Winter 2 0% 1 30/15 Summer1.004 15 Winter 2 0% 1 30/15 Summer1.005 15 Winter 2 0% 1 30/15 Summer1.006 15 Winter 2 0% 1 30/15 Summer

LvlEx.

PN

Water Lvl.(m)

SurchargedDepth (m)

FloodedVol (m³)

Flow/Capacity

Overflow(l/s)

Pipe Flow(l/s)

Status

1.000 287.171 -0.129 0.000 0.38 0.0 37.8 O K5 1.001 284.716 -0.084 0.000 0.70 0.0 70.4 O K

1.002 283.985 -0.065 0.000 0.83 0.0 69.7 O K2.000 283.564 -0.052 0.000 0.76 0.0 12.6 O K1.003 283.391 -0.034 0.000 0.97 0.0 80.9 O K1.004 283.359 -0.025 0.000 0.94 0.0 78.4 O K1.005 283.327 -0.017 0.000 1.00 0.0 82.0 O K1.006 283.290 -0.016 0.000 1.00 0.0 79.3 O K






Duration(s) (mins)15, 30, 60, 120, 240, 360, 480, 960, 1440, 2160, 2880, 4320, 5760, 7200, 8640, 10080


PN

Storm

ReturnPeriod

ClimateChange

Rank

First XSurcharge

First YFlood

First ZOverflow

O/FAct

1.000 15 Summer 30 0% 1 100/15 Summer1.001 15 Winter 30 0% 1 30/15 Summer 100/15 Summer1.002 15 Winter 30 0% 1 30/15 Summer2.000 15 Winter 30 0% 1 30/15 Summer1.003 15 Winter 30 0% 1 30/15 Summer1.004 15 Winter 30 0% 1 30/15 Summer1.005 15 Winter 30 0% 1 30/15 Summer1.006 15 Winter 30 0% 1 30/15 Summer

LvlEx.

PN

Water Lvl.(m)

SurchargedDepth (m)

FloodedVol (m³)

Flow/Capacity

Overflow(l/s)

Pipe Flow(l/s)

Status

1.000 287.216 -0.084 0.000 0.71 0.0 71.1 O K5 1.001 285.980 1.180 0.000 1.16 0.0 116.0 FLD RISK

1.002 284.948 0.898 0.000 1.39 0.0 115.8 SURCH'ED2.000 283.979 0.363 0.000 1.14 0.0 19.0 SURCH'ED1.003 283.753 0.328 0.000 1.59 0.0 133.0 SURCH'ED1.004 283.640 0.256 0.000 1.58 0.0 131.8 SURCH'ED1.005 283.526 0.182 0.000 1.72 0.0 141.6 SURCH'ED1.006 283.390 0.084 0.000 1.79 0.0 141.9 SURCH'ED






Duration(s) (mins)15, 30, 60, 120, 240, 360, 480, 960, 1440, 2160, 2880, 4320, 5760, 7200, 8640, 10080


PN

Storm

ReturnPeriod

ClimateChange

Rank

First XSurcharge

First YFlood

First ZOverflow

O/FAct

1.000 15 Winter 100 0% 1 100/15 Summer1.001 15 Winter 100 0% 1 30/15 Summer 100/15 Summer1.002 15 Winter 100 0% 1 30/15 Summer2.000 15 Winter 100 0% 1 30/15 Summer1.003 15 Winter 100 0% 1 30/15 Summer1.004 15 Winter 100 0% 1 30/15 Summer1.005 15 Winter 100 0% 1 30/15 Summer1.006 15 Winter 100 0% 1 30/15 Summer

LvlEx.

PN

Water Lvl.(m)

SurchargedDepth (m)

FloodedVol (m³)

Flow/Capacity

Overflow(l/s)

Pipe Flow(l/s)

Status

1.000 287.611 0.311 0.000 0.80 0.0 79.4 SURCH'ED5 1.001 286.008 1.208 8.548 1.17 0.0 117.4 FLOOD

1.002 285.017 0.967 0.000 1.41 0.0 117.4 SURCH'ED2.000 284.262 0.646 0.000 1.48 0.0 24.7 SURCH'ED1.003 283.832 0.407 0.000 1.67 0.0 140.0 SURCH'ED1.004 283.705 0.321 0.000 1.67 0.0 139.9 SURCH'ED1.005 283.579 0.235 0.000 1.88 0.0 155.2 SURCH'ED1.006 283.416 0.110 0.000 1.96 0.0 155.5 SURCH'ED


Paul Waite Associates Page 1Summit House New Line BacupRiparian Way Pond/WetlandKeighley BD20 7BWDate 11 November 2011 Designed By DMFile Checked ByInfrasoft Source Control W.11.4

Summary of Results for 2 year Return Period (+30%)

StormDuration(mins)

MaximumControl(l/s)

MaximumOverflow(l/s)

MaximumOutflow(l/s)

MaximumWater Level

(m OD)

MaximumDepth(m)

OverflowVolume(m³)

MaximumVolume(m³)

Status

15 Summer 9.0 0.0 9.0 282.2533 0.1532 0.0 34.7 O K30 Summer 11.4 0.0 11.4 282.2913 0.1912 0.0 43.9 O K60 Summer 12.4 0.0 12.4 282.3248 0.2247 0.0 52.1 O K120 Summer 13.0 0.0 13.0 282.3508 0.2507 0.0 58.7 O K180 Summer 13.1 0.0 13.1 282.3578 0.2577 0.0 60.4 O K240 Summer 13.1 0.0 13.1 282.3573 0.2572 0.0 60.3 O K360 Summer 12.9 0.0 12.9 282.3467 0.2467 0.0 57.6 O K480 Summer 12.6 0.0 12.6 282.3333 0.2332 0.0 54.2 O K600 Summer 12.3 0.0 12.3 282.3203 0.2202 0.0 50.9 O K720 Summer 12.1 0.0 12.1 282.3083 0.2082 0.0 48.0 O K960 Summer 11.3 0.0 11.3 282.2903 0.1902 0.0 43.6 O K

1440 Summer 9.7 0.0 9.7 282.2648 0.1647 0.0 37.4 O K2160 Summer 8.2 0.0 8.2 282.2393 0.1393 0.0 31.5 O K2880 Summer 7.1 0.0 7.1 282.2223 0.1223 0.0 27.4 O K4320 Summer 5.7 0.0 5.7 282.2003 0.1003 0.0 22.3 O K5760 Summer 4.9 0.0 4.9 282.1858 0.0858 0.0 18.9 O K7200 Summer 4.3 0.0 4.3 282.1753 0.0753 0.0 16.6 O K8640 Summer 3.8 0.0 3.8 282.1673 0.0673 0.0 14.8 O K

10080 Summer 3.5 0.0 3.5 282.1613 0.0613 0.0 13.4 O K15 Winter 10.1 0.0 10.1 282.2713 0.1712 0.0 39.0 O K30 Winter 12.2 0.0 12.2 282.3148 0.2147 0.0 49.6 O K60 Winter 13.0 0.0 13.0 282.3508 0.2507 0.0 58.6 O K120 Winter 13.4 0.0 13.4 282.3733 0.2732 0.0 64.3 O K180 Winter 13.4 0.0 13.4 282.3737 0.2737 0.0 64.5 O K

StormDuration(mins)

Rain(mm/hr)

Time-Peak(mins)

15 Summer 40.53 1730 Summer 28.23 2960 Summer 19.08 46120 Summer 12.69 80180 Summer 9.97 114240 Summer 8.38 148360 Summer 6.53 214480 Summer 5.48 276600 Summer 4.77 338720 Summer 4.27 398960 Summer 3.58 5201440 Summer 2.79 7642160 Summer 2.17 11242880 Summer 1.82 14764320 Summer 1.41 22045760 Summer 1.18 29367200 Summer 1.03 36728640 Summer 0.91 4408

10080 Summer 0.83 513615 Winter 40.53 1730 Winter 28.23 3060 Winter 19.08 48120 Winter 12.69 86180 Winter 9.97 124

Donna Metcalf

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StormDuration(mins)

MaximumControl(l/s)


MaximumOutflow(l/s)

MaximumWater Level

(m OD)

MaximumDepth(m)

OverflowVolume(m³)

MaximumVolume(m³)

Status

240 Winter 13.3 0.0 13.3 282.3668 0.2667 0.0 62.6 O K360 Winter 12.8 0.0 12.8 282.3438 0.2437 0.0 56.9 O K480 Winter 12.4 0.0 12.4 282.3208 0.2207 0.0 51.1 O K600 Winter 12.0 0.0 12.0 282.3013 0.2012 0.0 46.3 O K720 Winter 11.2 0.0 11.2 282.2878 0.1877 0.0 43.0 O K960 Winter 9.9 0.0 9.9 282.2668 0.1667 0.0 37.9 O K

1440 Winter 8.1 0.0 8.1 282.2378 0.1378 0.0 31.0 O K2160 Winter 6.4 0.0 6.4 282.2118 0.1118 0.0 25.0 O K2880 Winter 5.5 0.0 5.5 282.1958 0.0958 0.0 21.2 O K4320 Winter 4.3 0.0 4.3 282.1753 0.0753 0.0 16.6 O K5760 Winter 3.6 0.0 3.6 282.1633 0.0633 0.0 13.9 O K7200 Winter 3.1 0.0 3.1 282.1548 0.0547 0.0 12.0 O K8640 Winter 2.8 0.0 2.8 282.1493 0.0492 0.0 10.7 O K

10080 Winter 2.6 0.0 2.6 282.1447 0.0447 0.0 9.7 O K

StormDuration(mins)

Rain(mm/hr)

Time-Peak(mins)

240 Winter 8.38 158360 Winter 6.53 226480 Winter 5.48 288600 Winter 4.77 348720 Winter 4.27 410960 Winter 3.58 5301440 Winter 2.79 7782160 Winter 2.17 11442880 Winter 1.82 15004320 Winter 1.41 22085760 Winter 1.18 29367200 Winter 1.03 36728640 Winter 0.91 4384

10080 Winter 0.83 5144




StormDuration(mins)

MaximumControl(l/s)


MaximumOutflow(l/s)

MaximumWater Level

(m OD)

MaximumDepth(m)

OverflowVolume(m³)

MaximumVolume(m³)

Status




StormDuration(mins)

Rain(mm/hr)

Time-Peak(mins)



Donna Metcalf

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StormDuration(mins)

MaximumControl(l/s)


MaximumOutflow(l/s)

MaximumWater Level

(m OD)

MaximumDepth(m)

OverflowVolume(m³)

MaximumVolume(m³)

Status



10080 Winter 3.7 0.0 3.7 282.1642 0.0643 0.0 14.1 O K

StormDuration(mins)

Rain(mm/hr)

Time-Peak(mins)


10080 Winter 1.20 5136




StormDuration(mins)

MaximumControl(l/s)


MaximumOutflow(l/s)

MaximumWater Level

(m OD)

MaximumDepth(m)

OverflowVolume(m³)

MaximumVolume(m³)

Status




StormDuration(mins)

Rain(mm/hr)

Time-Peak(mins)



Donna Metcalf

Highlight




StormDuration(mins)

MaximumControl(l/s)


MaximumOutflow(l/s)

MaximumWater Level

(m OD)

MaximumDepth(m)

OverflowVolume(m³)

MaximumVolume(m³)

Status



10080 Winter 4.3 0.0 4.3 282.1747 0.0748 0.0 16.5 O K

StormDuration(mins)

Rain(mm/hr)

Time-Peak(mins)


10080 Winter 1.39 5136



Rainfall Details

Region ENG+WAL Shortest Storm (mins) 15Return Period (years) 100 Longest Storm (mins) 10080M5-60 (mm) 18.200 Summer Storms YesRatio-R 0.250 Winter Storms YesCv (Summer) 0.750 Climate Change % +30Cv (Winter) 0.840

Time / Area Diagram

Total Area (ha) = 0.520

Timefrom:

(mins)to:

Area(ha)

0 4 0.520

Donna Metcalf

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Tank/Pond Details

Invert Level (m) 282.100 Ground Level (m) 283.300

Depth(m)

Area(m²)

Depth(m)

Area(m²)

Depth(m)

Area(m²)

Depth(m)

Area(m²)

Depth(m)

Area(m²)

0.00 215.0 0.30 260.0 0.60 309.0 0.90 360.0 1.20 415.00.10 230.0 0.40 276.0 0.70 326.0 1.00 378.00.20 245.0 0.50 292.0 0.80 343.0 1.10 397.0

Hydro-Brake Outflow Control

Design Head (m) 0.760 Diameter (mm) 166Design Flow (l/s) 15.0 Invert Level (m) 282.100Hydro-Brake Type MD5

Depth(m)

Flow(l/s)

Depth(m)

Flow(l/s)

Depth(m)

Flow(l/s)

Depth(m)

Flow(l/s)

Depth(m)

Flow(l/s)

0.10 5.7 0.80 15.3 2.00 23.5 4.00 33.3 7.00 44.00.20 11.9 1.00 16.7 2.20 24.7 4.50 35.3 7.50 45.60.30 14.0 1.20 18.3 2.40 25.8 5.00 37.2 8.00 47.10.40 14.1 1.40 19.7 2.60 26.8 5.50 39.0 8.50 48.50.50 14.0 1.60 21.1 3.00 28.8 6.00 40.8 9.00 49.90.60 14.1 1.80 22.3 3.50 31.1 6.50 42.4 9.50 51.3

Pipe Overflow Control

Pipe Diameter (m) 0.150 Entry Loss Coef 0.500Slope (1:x) 150.0 Coef of Contraction 0.600Length (m) 15.000 Invert Level (m) 282.900Roughness (mm) 0.600




StormDuration(mins)

MaximumControl(l/s)


MaximumOutflow(l/s)

MaximumWater Level

(m OD)

MaximumDepth(m)

OverflowVolume(m³)

MaximumVolume(m³)

Status




StormDuration(mins)

Rain(mm/hr)

Time-Peak(mins)






StormDuration(mins)

MaximumControl(l/s)


MaximumOutflow(l/s)

MaximumWater Level

(m OD)

MaximumDepth(m)

OverflowVolume(m³)

MaximumVolume(m³)

Status



10080 Winter 4.4 0.0 4.4 282.1768 0.0768 0.0 17.0 O K

StormDuration(mins)

Rain(mm/hr)

Time-Peak(mins)


10080 Winter 1.43 5144

Donna Metcalf

Highlight




StormDuration(mins)

MaximumControl(l/s)


MaximumOutflow(l/s)

MaximumWater Level

(m OD)

MaximumDepth(m)

OverflowVolume(m³)

MaximumVolume(m³)

Status




StormDuration(mins)

Rain(mm/hr)

Time-Peak(mins)



Donna Metcalf

Highlight




StormDuration(mins)

MaximumControl(l/s)


MaximumOutflow(l/s)

MaximumWater Level

(m OD)

MaximumDepth(m)

OverflowVolume(m³)

MaximumVolume(m³)

Status



10080 Winter 5.7 0.0 5.7 282.2003 0.1003 0.0 22.3 O K

StormDuration(mins)

Rain(mm/hr)

Time-Peak(mins)


10080 Winter 1.87 5128


APPENDIX O Preliminary Drainage Strategy