Land south of the A513, Orgreave, Alrewas
12 HYDROGEOLOGY AND FLOOD RISK
The following Technical Appendices referred to in this chapter can be found at Appendix 5 to this document.
Appendices:
Appendix 5.1 – Site Visit Photographs
Appendix 5.2 – Alrewas Quarry Factual Report – Ground investigation by Geotechnics
Appendix 5.3 – Alrewas Quarry Factual Report – Geophysics Survey by SUMO
Appendix 5.4 – Surface Water Quality Results
Appendix 5.5 – Groundwater Quality Results
Appendix 5.6 – Orgreave Farm Dewatering Assessment
Appendix 5.7 – Orgreave Farm Drainage Strategy
Appendix 5.8 – Drawing - Site Survey: Hydro Detail and BHs by CEMEX
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12.1 Introduction
12.1.1 This chapter of the Environmental Statement (ES) has been prepared by Stantec UK Ltd (Stantec) and considers the potential hydrogeological and hydrological impacts associated with the proposal. It also includes an assessment of flood risk both to and from the Application Site.
12.1.2 Where relevant, mitigation measures are proposed to minimise the impacts of the proposed development during both the preparation, operational and restoration phases of the scheme. Any anticipated residual effects of the proposals are then stated.
12.1.3 A full description of the Proposal is outlined in Chapter 2 of this ES. This section provides further details on aspects relevant to the water environment.
12.1.4 It is proposed to dewater in order to work part of the quarry voids dry. The final 4 m of each void will be worked wet and dewatering would be undertaken to this level to maintain these levels. Water derived from the dewatering process would be used on-site under the terms of a full abstraction licence for wheel washing, dust suppression and mineral processing. Water abstracted from the quarry void that is not consumed would be discharged to the Pyford Brook under the conditions of a dewatering transfer licence and a discharge permit. Suspended solids would be allowed to settle out of suspension in settlement lagoons prior to discharge off-site.
12.1.5 Drainage from the Application Site would be conveyed to waterbodies and quarry voids at the Application Site prior to discharge off-site to the Pyford Brook. Once restored, drainage from the Application Site would be captured by the restored lake in the quarry void.
Scope
12.1.6 This chapter covers the requirements of a Hydrogeological Impact Assessment (HIA) and Flood Risk Assessment (FRA). The scope of work undertaken for this ES chapter includes the following:
Review of the baseline hydrogeology and hydrology for the Application Site and surrounding area;
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identification of receptors and assessment of likely significant effects from the Proposal based on a dewatering assessment (Appendix 5.6);
recommendations for appropriate monitoring and mitigation measures; and
a drainage strategy to manage and mitigate flood risks posed to and from the Application Site, appended in Appendix 5.7.
12.1.7 The chapter includes the following tables and figures:
List of Figures
Figure 12.1 ...... Application Site and study area Figure 12.2 ...... Surrounding topography Figure 12.3 ...... Bedrock geology Figure 12.4 ...... Superficial geology Figure 12.5 ...... Contact between sand and gravel and Gunthorpe Member Figure 12.6 ...... Mineral thickness Figure 12.7 ...... Neighbouring historical and authorised landfills Figure 12.8 ...... Surface water features Figure 12.9 ...... Groundwater monitoring locations Figure 12.10 ...... Groundwater level hydrographs Figure 12.11 ...... Local hydrogeology at the Application Site Figure 12.12 ...... Fluvial flood risk zones Figure 12.13 ...... Surface water flood risk zones Figure 12.14 ...... Reservoir flood risk map Figure 12.15 ...... Surface water quality monitoring locations Figure 12.16 ...... Neighbouring licenced surface water abstractions Figure 12.17 ...... Neighbouring groundwater abstractions Figure 12.18 ...... Neighbouring designated sites Figure 12.19 ...... Conceptual hydrogeology cross section
List of Tables
Table 12.1 ...... Methodology for assessing receptor sensitivity Table 12.2 ...... Assessing magnitude of impact Table 12.3 ...... Determination of level of effect and significance
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Table 12.4 ...... Summary of local geology at the Application Site Table 12.5 ...... Historical and authorised landfills within 4 km of the Application Site Table 12.6 ..... Mean monthly rainfall totals for the EA rain gauge at Lichfield (2001 - 2018) Table 12.7 ...... Surface watercourses within 4 km of the Application Site Table 12.8 ...... Summary of surface waterbodies within 4 km of the Application Site Table 12.9 ...... Flow statistics for the River Trent at Yoxhall (1959 – 2018) Table 12.10 ...... Groundwater monitoring locations at and around the Application Site Table 12.11 ...... Groundwater level summary statistics Table 12.12 . Hydraulic conductivity estimates from particle size distributions presented by (Geotechnics, 2017) Table 12.13 ...... Flood risk vulnerability and flood zone compatibility Table 12.14 ...... Licenced abstractions from surface water point sources Table 12.15 ...... Licenced abstractions from surface water reaches Table 12.16 ...... Licenced groundwater abstractions within the study area Table 12.17 ...... Private abstractions in Lichfield District within 4 km Table 12.18 ...... Potential impacts of quarrying activities and typical mitigation measures Table 12.19 ...... Summary of receptors with potential impact from the Application Site Table 12.20 ...... Summary of potential impacts to nearby waterbodies Table 12.21 ...... Watercourses within the radius of influence Table 12.22 ...... Summary of impacts Table 12.23 ...... Assessment Summary of Residual Environmental Effects
Study Area
12.1.8 The study area is the Application Site (which is currently greenfield) and, when considering potential receptors, the area that lies within 4 km of the Application Site. Much of the content of this chapter focusses on the area shown in Figure 12.1 which is where the identified receptors are located. Figure 12.1 also shows the proposed excavation areas.
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12.2 Methodology
Previous Assessment Stages
12.2.1 No previous impact assessments relevant to the Application Site have been identified.
Legislation and Planning Policy Guidance
12.2.2 The HIA element of this assessment conforms to the requirements of Groundwater Protection (Environment Agency, 2017) with regards to the technical approach to ensure the protection of groundwater in the vicinity of the Application Site.
12.2.3 The FRA element of this assessment has been written and submitted in accordance with guidelines laid out in the Planning Practice Guidance (PPG) (Department for Communities and Local Government, 2014) for the National Planning Policy Framework (NPPF) (Department for Communities and Local Government, 2012). The principal objective of the FRA element is to demonstrate that the Proposal will not increase the flood risk at the Application Site or elsewhere.
12.2.4 Site-specific calculations (see Appendix 5.7) have been performed to estimate surface water runoff generation for the 1 in 100 year event plus allowance for climate change using the industry standard advice given in the NPPF and EA guidance. Where necessary, appropriate site-specific flood risk mitigation measures have been included with recommendations for a strategy for managing and mitigating any flood risk posed to, or resulting from, the Application Site.
Local Planning Policy
12.2.5 Relevant local planning policies are listed below:
Minerals Local Plan for Staffordshire 2017 Strategic Objective 4 (restoration that enhances local amenity and the environment) with specific regard to measures to manage flood risk to deliver flood risk management benefits wherever possible and adapting restoration and aftercare to the effects of climate change on communities, biodiversity and landscape.
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Minerals Local Plan for Staffordshire 2017 Policy 4 Minimising the impact of mineral development – considering the water environment including flood risk, pollution, over- abstraction, hydrology and hydrogeology.
Minerals Local Plan for Staffordshire 2017 Policy 6 restoration of mineral sites with regards to flood risk and reducing flood risk where possible.
Lichfield District Local Plan Strategy 2015 Core Policy 3 Delivering Sustainable Development, with regard to flood risk assessments and drainage.
Assessment Methodology
12.2.6 Hydrological and hydrogeological baseline conditions within the Application Site and surrounding area have been established and a conceptual model has been developed based on these. The baseline description has been informed using the data sources outlined in the baseline description section (below). In characterising baseline conditions, potential receptors which the Proposal could affect have been identified. This work has been further informed by a site visit and water features survey undertaken on 5 September 2019
12.2.7 An assessment of the potential hydrological and hydrogeological impacts, including an assessment of flood risk, has been carried out relative to the baseline conditions to assess any likely significant effects of the Proposal. The approach taken considers a complete list of likely significant effects that have been known to occur for quarrying developments. Likely significant effects are then considered on receptors identified during the assessment of baseline conditions. If any effect is considered to be significant, mitigation measures are outlined.
12.2.8 To assess whether an effect is considered significant, an impact assessment methodology is used which is described in the following sections.
Receptor Sensitivity
12.2.9 The sensitivity of receptors is based on their designation status or water resource value, as is described in Table 12.1.
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Table 12.1 Methodology for assessing receptor sensitivity
Sensitivity Description Examples
Very High Receptor with an importance and A water resource making up a vital component of rarity at an international level with a SAC or SPA under the EC Habitats Directive limited potential for substitution A water body achieving a status of ‘High status or potential’ under the Water Framework Directive (WFD) Principal aquifer providing potable water to a large population
High Receptor with a high quality and A water resource designated or directly linked to rarity at a national or regional level an SSSI and limited potential for substitution Principal aquifer providing potable water to a small population A river designated as being of Good status or with a target of Good status or potential under the WFD
Medium Receptor with a high quality and Secondary aquifer providing potable water to a rarity at a local scale; or Water small population resource with a medium quality and An aquifer providing abstraction water for rarity at a regional or national scale agricultural and industrial use
Low Receptor with a low quality and A non ‘main’ river or stream or other water body rarity at a local scale without significant ecological habitat Low vulnerability groundwater
Negligible Receptor of extremely limited extent No significant groundwater present and value.
Determining Impact Magnitude
12.2.10 The magnitude of a potential impact on a receptor depends on the nature and extent of the Proposal, and is independent of the sensitivity of the water resource, as described in Table 12.2.
Table 12.2 Assessing magnitude of impact
Magnitude Description Examples of Impact Results in a major Pollution of potable source of abstraction change to attributes Change in WFD classification of a water body Substantial Compromise employment source Loss of flood storage/increased flood risk Results in impact on Contribution / reduction of a significant proportion of the effluent in a integrity of attribute receiving river, but insufficient to change its WFD classification Moderate or loss of part of Reduction / increase in the economic value of the feature attribute Results in minor Measurable changes in attribute, but of limited size and/or Slight impact to attributes proportion
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Results in an impact Physical impact to a water resource, but no significant reduction/ on attribute but of increase in quality, productivity or biodiversity Negligible insignificant No significant impact on the economic value of the feature magnitude to affect No increase in flood risk use and/or integrity
Determining Significance and Nature of Effects
12.2.11 The significance of effect is determined by combining the magnitude of impact with the sensitivity of the receptor, as shown in Table 12.3.
12.2.12 If an impact magnitude is negative then the resulting effect is described as being adverse; if an impact magnitude is positive the resulting effect is classed as being beneficial. In this chapter any significance of effect that is defined as being moderate (whether it is adverse or beneficial) or greater is defined as being significant.
Table 12.3 Determination of level of effect and significance
Magnitude of Impact Sensitivity Substantial Negligible Moderate magnitude Slight magnitude magnitude magnitude
Very High Major Major Major/Moderate Neutral
High Major Major/Moderate Moderate/Minor Neutral
Medium Major/Moderate Moderate Minor Neutral
Low Moderate/Minor Minor Neutral Neutral
Negligible Minor/Neutral Minor/Neutral Neutral Neutral
EIA Assumption Limitations
12.2.13 Where uncertainty exists, such as estimating dewatering rates and runoff volumes, conservative assessments have been made so that likely significant effects are not understated.
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12.3 Baseline Environment
Data sources
12.3.1 The information and assessments in this ES chapter are predominantly based on secondary data analysis associated with the Application Site and surrounding area. The main sources of data are summarised below:
Proposed development plans provided by the Applicant (ES - Volume 1);
Geological data from British Geological Survey (BGS) mapping and borehole logs;
Borehole logs for the Application Site (Geotechnics, 2017);
Soil types and permeability data from the 1:250,000 soils map (NSRI, 2019);
Monitoring data for the Application Site collected by the Applicant including groundwater levels; groundwater quality data and topographic survey;
Ordnance Survey mapping;
Site visit undertaken by Stantec on 5 September 2019;
Information on neighbouring private water supply abstractions from Lichfield District Council; and
Data from EA including flood mapping, water quality, rainfall, historical and authorised landfill data, LiDAR data and abstraction licences.
Application Site Setting
12.3.2 The Application Site is located approximately 4 km north of Lichfield and 1.1 km west of Alrewas in Staffordshire (nearest postcode: DE13 7DD). The Application Site is bounded by the A513 and arable agricultural land to the north, Pyford Brook to the south, and Hay End Lane to the west. Figure 12.1 shows the location of the Application Site and the surrounding area.
12.3.3 The Application Site is currently a greenfield site used as arable farmland. The Application Site comprises four fields with trees along the field boundaries.
12.3.4 Land immediately surrounding the Application Site is utilised for various agricultural, industrial, recreational and rural purposes. Across the A513 from the Application Site is a
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National Grid Compressor Station. Fradley Distribution Park lies 1.6 km to the south. Alrewas Hayes, a wedding and events venue, is located approximately 640 m to the west. Fradley Junction is a recreational destination at the junction of the Trent and Mersey Canal and the Coventry Canal and features Fradley Pool Nature Reserve, two cafes, a pub and a caravan park. It is located approximately 800 m to the south-west.
12.3.5 The wider study area contains a number of current and former sand and gravel workings, particularly east of the Application Site centred on the River Trent and River Tame. The River Trent is located 950 m to the north at its closest approach and flows eastwards along a meandering course to Alrewas. The Trent and Mersey Canal is located 210 m south of the Application Site.
12.3.6 Numerous hamlets and farms lie within 1 km of the Application Site. The closest of these are Alrewas Hayes (120 m south-west), Orgreave (440 m north-west), Wellfield Farm (520 m north-west), Overley Farm (620 m north-east), Sandyhill (670 m south), The Sale Farm (760 m south), Lupin Farm (780 m north-west), and Fradley Junction (800 m south). Larger settlements lie more distant from the Application Site including Fradley (1.2 km south), Fradley South (1.5 km south), Alrewas (1.1 km east) and Kings Bromley (2.2 km north-west).
12.3.7 Figure 12.2 shows a map of LiDAR topography data around the Application Site. The Application Site lies in the flat, low lying area in the Trent Valley. Ground levels at the Application Site range from 55.5 to 58.9 m AOD. The Application Site gently slopes towards Drain A and the Pyford Brook. Land rises north of the River Trent and to the south approximately 1 km from the Application Site, with Fradley at approximately 61 m AOD. The River Trent is at around 55 m AOD north of the Application Site and rises to 91 m AOD at Wynchnor Park (around 2.7 km north).
Bedrock Geology
12.3.8 The bedrock geology of the area surrounding the Application Site consists of various Triassic aged strata. Figure 12.3 shows the bedrock geology as taken from the 1:50,000 scale geological map of the area (BGS, 2011). The regional bedrock geology is summarised in Table 12.4.
12.3.9 The Application Site is underlain by Triassic mudstone, siltstone and sandstones of the Mercia Mudstone Group. Within the Mercia Mudstone Group, the Application Site is
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underlain by the Gunthorpe Member of the Sidmouth Mudstone Formation. The Gunthorpe Member is a red-brown mudstone with some dolomitic siltstone and fine-grained sandstone layers. North of the Application Site, BGS mapping does not split the Mercia Mudstone Group into its constituent formations.
12.3.10 The Sidmouth Mudstone Formation is underlain by the Tarporley Siltstone Formation and this unit crops out 1.8 km south of the Application Site at its closest approach. This unit comprises interbedded mudstone, siltstone and sandstone.
12.3.11 The older, Triassic Helsby Sandstone Formation, which crops out 2.2 km south of the Application Site, forms part of the Sherwood Sandstone Group that underlies the Mercia Mudstone Group.
12.3.12 Locally, the rocks young to the north. A series of faults are located around the study area, the closest of which lies 1.3 km north-east of the Application Site.
Table 12.4 Regional bedrock stratigraphic sequence
At Application Period Group Formation Description Site? Siltstones and mudstones, generally Sidmouth Mudstone structureless. Includes Gunthorpe Yes Member and Edwalton Member Mercia Mudstone Interlaminated and interbedded Tarporley Siltstone At depth siltstone, mudstone and sandstone Triassic
Sherwood Helsby Sandstone Fine- to medium grained sandstones At depth Sandstone
Superficial Geology
12.3.13 Figure 12.4 shows the superficial deposits that overlie the bedrock strata around the Application Site. Superficial coverage at and around the Application Site is extensive. Superficial deposits in the area are generally sand and gravel deposits of glaciofluvial or fluvial origin deposited by the River Trent and its tributaries.
12.3.14 The Holme Pierrepont Sand and Gravel Member crops out at the Application Site and comprises the economic mineral to be extracted. This unit is a glaciofluvial deposit of poorly
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sorted, immature, matrix-supported sandy gravels. This unit is typically up to 8 m thick in the Trent valley and covers much of the area around the Application Site.
12.3.15 Around 540 m to the north, around the River Trent, alluvium crops out. Alluvium is also associated with other smaller watercourses including the Bourne Brook (but not the Pyford Brook). Further north (2.2 km north of the Application Site) on the higher ground, glacial till deposits of the Brewood Till Formation and Thrussington Member are present. Glaciofluvial sand and gravel sheet deposits crop out 540 m south of the Application Site. River Terrace deposits and the Egginton Common Sand and Gravel Member also crop out in the area around the Application Site.
Soils
12.3.16 Loamy soils with naturally high groundwater are mapped as being present at the Application Site (NSRI, 2019). The northern part of the haul road is an area of free-draining slightly acid loamy soil (NSRI, 2019).
Local Geology
12.3.17 Information on the geology in the vicinity of the Application Site has been obtained from the following sources:
Borehole logs drilled in 2017; and
Publicly available geology maps.
12.3.18 Twelve investigation boreholes were drilled at and around the Application Site in 2017 (Geotechnics, 2017). They show three or four layers of sand and gravel in varying proportions. The depth to the Gunthorpe Member bedrock (Mercia Mudstone Group) ranges between 9.2 and 15.5 m, with an overlying sand and gravel thickness of 8.7 - 15 m. A summary of the local geology based on these boreholes is provided in Table 12.4.
12.3.19 Figure 12.5 shows the contact between the sand and gravel and the underlying Gunthorpe Member (described as reddish-brown mudstone). Based on the borehole logs, this contact varies across the Application Site from 42.3 m AOD in the south-west to > 47 m AOD in the north. The contact varies non-uniformly, but is typically at around 45 – 46 m AOD.
12.3.20 Figure 12.6 shows the thickness of the sand and gravel at the Application Site. Mineral thickness is related to the elevation of the contact with the Gunthorpe Member. Based on
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the borehole logs, mineral thickness increases to a maximum of 15 m in the south-west of the Application Site from a low of around 8.7 m in the north. Mineral thickness is greatest in the western excavation phases (11 – 15 m) and lowest in the eastern phase (10 – 11 m)
12.3.21 The sand and gravel is overlain by topsoil, which is mostly described as dark brown, slightly gravelly, slightly clayey sand. Towards the Pyford Brook at WM12-17 and WM09-17, topsoil becomes more clayey, being described as slightly sandy, slightly gravelly, clay. At WM12-17, the topsoil is underlain by 0.2 m of slightly sandy, slightly gravelly clay. Sand and gravels beneath the topsoil are variably described as brown sandy gravel to slightly clayey sand. The gravel clasts consist of fine to coarse subangular to subrounded mudstone and quartzite. The grain size of the sand and the gravel is variably described as fine to coarse.
Table 12.4 Summary of local geology at the Application Site
Lithology Local Thickness (m) Typical unit description
Topsoil 0.3 – 0.5 Slightly gravelly and slightly clayey sand topsoil
Variable proportions of sand and gravel. Typically, Sand and 8.7 – 15 gravel is sub-angular to sub rounded quartzite and gravel mudstone. Sand is light brown
Mudstone Thickness not proven at Application Site Reddish brown mudstone
12.3.22 BGS borehole SK11SE8 is located 680 m south-east of the Application Site. This borehole was drilled to a depth of 786 m. This borehole proved “marl” (interpreted to be Mercia Mudstone Group) to a depth of 158 m (a 14 m thick layer of fine grained sandstone was encountered at 124 m depth) before well sorted sandstone was encountered. This sandstone unit could be the Helsby Sandstone Formation. At 250 m depth, the sandstone becomes pebbly.
Infilled Ground and Landfilling
12.3.23 Details of existing and historical landfills have been obtained from Magic Map (Defra, 2019). Eight historical landfills and two authorised landfills lie within 4 km of the Application Site. Further details on these landfills are shown in Table 12.5 and the closest landfills are shown in Figure 12.7.
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12.3.24 Landfill at the corner of Fox Lane is located 1.8 km to the south-east of the Application Site and is the closest historical landfill. This accepted household waste and operated from 1952 to 1965. The operator is unknown. This landfill is located adjacent to, and west of, the A38. Other historical landfills are located more than 2.5 km distant.
12.3.25 Tarmac Alrewas Quarry is the closest authorised landfill site and is located 2.1 km to the east. It was licensed in 2017 to accept inert waste only.
Table 12.5 Historical and authorised landfills within 4 km of the Application Site
Dates Landfill Name Operator Distance Status Waste Type operational
Landfill at the corner Unknown 1.8 km SE Historical 1952-1965 Household of Fox Lane, Alrewas
Tarmac Alrewas Tarmac Trading 2.1 km E Authorised August 2017- Inert Landfill Quarry Ltd
Refuse Treatment 2.75 km Unknown Historical Unknown Unknown Plant, Watery Lane SW
Tarmac Whitemoor Haye, November Non-biodegradable Aggregates 2.8 km SE Authorised Barley Green Lane 2000- waste Limited Shaw Lane 1951-1989 Commercial and (including Riley Hill R D E Phillips 3 km W Historical (1981-1989) household, (Inert) Farm)
Brickyard Farm, W A Mansell 3 km S Historical 1931-1989 Industrial Fradley
Croxhall Redlands Quarry/Broadfields 3.4 km E Historical 19789-1990 Inert, commercial Aggregates Ltd Farm Pit
Barr Lane Unknown 3.6 km NE Historical 1960-1973 Unknown
Junction of Barr Lane Henry Edwards 3.7 km NE Historical 1969-1980 Inert, industrial and Dogshead Lane Ltd
General Electricity Elford 3.9 km SE Historical 1972-2004 Inert, industrial Generating Board
Rainfall
12.3.26 The EA provided rainfall data for Lichfield rainfall station in August 2019. Lichfield rain station is located around 4.8 km south of the Application Site on the outskirts of Lichfield, close to Lichfield Trent Valley railway station. The rain gauge is at approximately 76 m AOD compared to the Application Site elevation of around 57 m AOD. For the period
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2001 to 2018 (inclusive), mean annual rainfall was 662 mm. Over this time, annual rainfall fluctuated from 433 – 926 mm, with the lowest rainfall being in 2011 and highest in 2012.
Table 12.6 Mean monthly rainfall totals for the EA rain gauge at Lichfield (2001 - 2018)
Month Average rainfall (mm)
January 55.1
February 44.5
March 47.1
April 47.9
May 56.1
June 60.2
July 59.6
August 58.6
September 48.1
October 63.5
November 61.3
December 60.2
Total 662.0
12.3.27 Table 12.6 shows mean monthly rainfall totals for the period 2001 - 2018 (inclusive). Mean monthly rainfall varies from 44.5 – 63.5 mm during the year, being generally similar throughout the year.
12.3.28 Standard Average Annual Rainfall (SAAR) for the Application Site is 655 mm (HR Wallingford, 2019). This is consistent with the rainfall recorded at Lichfield.
WFD Classification and Water Availability
12.3.29 The Application Site is located in the Pyford Brook surface water catchment (ID: GB104028047250), which covers an area of 2868 ha. In the 2016 status for Water Framework Directive (WFD) cycle 2, this catchment has “bad” and “good” classifications for ecological and chemical status respectively. The overall status is classified as “bad”.
12.3.30 The Application Site is also located on the far eastern part of the EA’s Staffordshire Trent Valley catchment abstraction licencing strategy (CAMS) area. Water is available for
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abstraction from surface water sources at Q30 and Q50 flows and restricted for Q70 and Q95 flows.
Surface Water Features
12.3.31 Figure 12.8 shows surface watercourses and waterbodies in the area around the Application Site (features in this figure are labelled as per Table 12.7). The dominant surface water feature in the region is the River Trent (WCC), which flows eastwards along a meandering course to the north of the Application Site, turning to flow northwards at Alrewas. The Application Site lies in the wide, flat Trent Valley. The source of the River Trent lies approximately 50 km to the west near Biddulph Moor in the Staffordshire Moorlands and ends at Trent Falls at its confluence with the River Humber.
12.3.32 The River Tame, located 3.3 km to the east, flows north from Birmingham and joins the River Trent east of Alrewas, approximately 3.8 km east of the Application Site.
12.3.33 The eastwards flowing Pyford Brook (WCB) bounds the Application Site to the south and is a tributary of the River Trent, joining the River Trent on the western outskirts of Alrewas. Pyford Brook is formed from the convergence of the Full Brook and Curborough Brook 2.4 km south-west of the Application Site. These watercourses appear to be sourced 3.9 km and 4 km south-west of the Application Site from waterbodies or issues. A small tributary of the Pyford Brook flows eastwards to the north of the Application Site and joins the Pyford Brook 330 m east and downstream of the Application Site. This feature will be referred to as Drain A (WCA) for the remainder of this chapter. Drain A borders the eastern phases to the north and flows through the area where the haul road is proposed to pass. The source of Drain A lies 700 m west of the Application Site.
12.3.34 The Trent and Mersey Canal (WCJ) lies 210 m south of the Application Site and traverses roughly south-west to north-east, linking with the River Trent for a short stretch just north of Alrewas to the north-east of the Application Site. The Coventry Canal (WCK), traversing north-west - south-east, meets the Trent and Mersey Canal 910 m to the south of the Application Site. It heads south-east to the northern boundary of Fradley South and then heads south. These canals are assumed to be clay lined.
12.3.35 A number of brooks and small rivers lie in the study area and drain mainly agricultural land and are tributaries of the River Trent. Some of the watercourses coincide with field
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boundaries and are likely to be field drains (similar to Drain A). There are a number of other watercourses in the area around the Application Site, these are listed in Table 12.7.
12.3.36 There are a number of small ponds and lakes to the south of the Application Site around Fradley Junction, Fradley and Fradley South. Fradley Reservoir lies 580 m to the south of the Application Site and was constructed to supply water to the Trent and Mersey Canal. A smaller pond named Sale Pit lies 920 m to the south of the Application Site. Bown Pool is a fishing pond located in Fradley South 1.8 km south of the Application Site.
Table 12.7 Surface watercourses within 4 km of the Application Site
Water feature Name Distance Description1 No. At northern boundary Field drain/stream flowing west to east through WCA Drain A and flows through Application Site. Tributary of Pyford Brook Application Site Main river flowing west to east and joining the River WCB Pyford Brook Immediately south Trent at Alrewas. Manmade water feature (presumed lined) traversing WCJ Trent & Mersey Canal 210 m south east-west and joining with River Trent for a short section at Alrewas WCH Unnamed ditch 496 m south Ditch flowing from Sale Pit to Alrewas Tributary of River Trent flowing from Lupin through WCF Unnamed stream 600 m north Orgreave Field drain / stream flowing south-west to north-east WCD Ashby Sitch 760 m west joining with Bourne Brook near Orgreave. Brook flowing from south-west to north-east to the WCE Bourne Brook 915 m north-west Trent at Orgreave Manmade water feature (presumed lined) traversing WCK Coventry Canal 910 m south approximately north-south and joining with the Trent & Mersey Canal at Fradley Junction Main river. Flowing 298 km from Biddulph Moor in WCC River Trent 950 m north Staffordshire to the Humber Estuary in Lincolnshire Tributary of the Bourne Brook, flows east to west from WCG Crawley Brook 1.2 km north-west Kings Bromley Main river on the true left bank of the River Trent WCI River Swarbourn 1.2 km north-east flowing northwest to south-east and joining with the River Trent near Potters Meadow 1 Unless stated otherwise, these features are ordinary watercourses
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Table 12.8 Summary of surface waterbodies within 4 km of the Application Site
Water feature Name Distance Description No. WB5 Unknown 300 m west Two ponds, both appear manmade and could be lined 310 m south- WB11 Unknown Two rectangular ponds at Alrewas Hayes Cottages west Linear pond and nearby ditch near “The Belt”, north of Alrewas Hayes. The rectangular shape of this waterbody WB4 Unknown 480 m west suggests that it is manmade and is therefore presumed to be lined 510 m south- WB3 Unknown Pool in woods south-west of Alrewas Hayes Cottages west Fradley Reservoir and Manmade pool dug to feed the Trent and Mersey Canal, WB1 two smaller pools to 580 m south now a nature reserve. This is presumed to be lined north-east Manmade pool at Alrewas Hayes (wedding venue). WB2 Alrewas Hayes Pool 750 m west Presumed lined. Pool with reeds next to Sale Lane. Name indicates this is a WB6 Sale Pit 920 m south former quarry void. Pond north of Fradley Depression on edge of field. Dry during visit, possibly WB8 1 km south-east west of Long Lane ephemeral. Rectangular Pond northwest of Old Hall Farm in centre of WB7 Unknown 1.2 km south field Pool east of Woodend 1.7 km south- WB10 Pool in woodland, possibly connected to Pyford Brook. Common Barn west Former clay and gravel pit now flooded. Presumed to be WB9 Bown Pond 1.8 km south unlined as also used as a SuDS feature
Surface Water Flow and Levels
12.3.37 The nearest flow gauging station is on the River Trent at Yoxhall (ID: 28012), 2.9 km to the northwest and upstream of the Application Site (CEH, 2019). Flows recorded at this gauging station are therefore expected to be lower than those recorded in the reach closest to the Application Site.
12.3.38 The baseflow index for the River Trent at Yoxhall is 0.69 indicating that groundwater contributions to flow are significant. Flow statistics for this gauging location are provided in
Table 12.9. Recorded low flows (Q95) are 4,612 l/s. Table 12.9 also provides estimates of
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recharge and effective rainfall based on Q95 and mean flows respectively. Recharge is estimated to be around 18% of mean annual rainfall (2001 – 2018 at Lichfield) at the Application Site. This may be an underestimate, because flow will be reduced by anthropogenic abstractions from the River Trent upstream (see below).
Table 12.9 Flow statistics for the River Trent at Yoxhall (1959 – 2018)
Distance Description
95% Exceedance (Q95) 4.612
70% Exceedance (Q70) 7.484
50% Exceedance (Q50) 9.62
10% Exceedance (Q10) 23.85 Mean Flow 12.77 Baseflow index (-) 0.69 Catchment Area (km2) 1,229 Estimated mean annual effective precipitation 328 (mm)
Estimated recharge from Q95 (mm) 118
12.3.39 During the site walkover, flows in Drain A were observed to be low with water depth of approximately 5 cm. The banks are vegetated with scrub vegetation, bushes and trees, obscuring the view of the water along long stretches suggesting that flows are very rarely high. Site visits undertaken by the Applicant since May 2017 have demonstrated that flows within Drain A vary and that Drain A is ephemeral.
12.3.40 At the time of the site visit, Pyford Brook had low to moderate flows with up to 10 cm water depth at the Application Site, and the banks are also heavily vegetated. Photographs are provided in Appendix 5.1. Based on survey data from the Applicant from September 2019 (provided in Appendix 5.8), the water level in Drain A varies from 56.5 m AOD on the western site boundary to 55.2 m AOD on the eastern boundary. Water levels in the Pyford Brook were 56.6 m AOD at the western boundary and 55.3 m AOD on the eastern boundary.
Site Water Management
12.3.41 The Application Site is currently used for agricultural purposes and as such there is no site water management. Surface water runoff flows to Drain A and the Pyford Brook.
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Groundwater Classifications and Systems
12.3.42 The Gunthorpe Member (along with the rest of the Mercia Mudstone Group) is classified by the EA as a Secondary B Aquifer. The superficial sand and gravel deposits are classified as a Secondary A aquifer. Secondary A aquifers are permeable layers capable of supporting water supplies at a local rather than strategic scale and can be an important source of base flow to rivers. Secondary B aquifers are mainly lower permeability layers that may store and yield limited amounts of groundwater through fissures, openings or eroded layers. The Application Site lies in the Staffordshire Trent Valley - Mercia Mudstone East & Coal Measures groundwater catchment and the groundwater body are classified as Good for both quantitative and chemical status.
Groundwater Levels and Flow
12.3.43 Groundwater levels at the Application Site have been monitored monthly by the Applicant from ten piezometers and data are available from March 2018 to January 2020 (inclusive). Construction details of the ten monitoring locations are summarised in Table 12.10. The monitoring locations are shown in Figure 12.9. These piezometers are screened within the sand and gravel aquifer (Holme Pierrepont Sand and Gravel Member). The EA confirmed that it is not currently monitoring groundwater levels within the study area.
Table 12.10 Groundwater monitoring locations at and around the Application Site
Screened Borehole Depth Screened Easting1 Northing1 Elevation Screened Lithology ID (m) Depth (m bgl) (m AOD)
WB01 414736 315786 12 3 - 12 54.38 - 45.38 Sandy gravel WB02 414532 315317 11 1.5 - 10.9 55.77 - 46.37 Sandy gravel / clayey sand WB03 414446 314841 15.7 3 - 15.7 54.78 - 42.08 Sandy gravel / gravelly, clayey sand / sandy, clayey gravel WB04 414779 314900 11.7 1.5 - 11.7 55.51 - 45.31 Sandy gravel WB05 415247 314954 11 1.5 - 11 54.73 - 45.23 Sandy gravel WB06 415037 315084 11.3 1.5 - 11 55.6 - 46.1 Sandy gravel / gravelly, clayey sand / sandy, clayey gravel WB07 415090 315251 12.2 1.5 - 12.2 54.95 - 44.25 Sandy, clayey gravel / gravelly clayey sand WB08 415330 315254 11 1.5 - 11 54.64 - 45.14 Sandy gravel / Gravelly sand WB09 415388 315450 7.52 1.5 - 7.4 54.86 - 48.96 Sandy gravel
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Screened Borehole Depth Screened Easting1 Northing1 Elevation Screened Lithology ID (m) Depth (m bgl) (m AOD)
WB10 415107 315468 10 1.5 - 10 55.26 - 46.76 Sandy gravel / gravelly, clayey sand / sandy, clayey gravel 1These grid references are based on a site survey undertaken after completion of the borehole logs in the Ground Investigation report (Appendix 5.2). Therefore, grid references presented here are correct but differ slightly from those in Appendix 5.2.
12.3.44 Summary groundwater level statistics are shown in Table 12.11. Groundwater levels are typically recorded on a monthly basis. Groundwater levels are always < 2 m below ground level and, with the exception of WB03, generally < 1.5 m below ground level.
Table 12.11 Groundwater level summary statistics
Groundwater Level (m AOD) Groundwater Level (m bgl) Borehole ID Min Mean Max Min Mean Max
WB01 55.89 56.29 56.97 0.41 1.09 1.49 WB02 56.24 56.59 57.17 0.10 0.68 1.03 WB03 55.98 56.28 56.87 0.91 1.50 1.80 WB04 55.80 56.10 56.65 0.36 0.91 1.21 WB05 55.14 55.43 55.73 0.50 0.80 1.09 WB06 55.50 55.78 56.20 0.90 1.32 1.60 WB07 55.51 55.77 56.11 0.34 0.68 0.94 WB08 55.05 55.36 55.71 0.43 0.78 1.09 WB09 54.92 55.34 55.80 0.56 1.02 1.44 WB10 55.76 56.12 56.66 0.10 0.64 1.00
12.3.45 Groundwater hydrographs are shown in Figure 12.10. Groundwater levels range between 54.9 m AOD and 57.2 m AOD and at each location typically vary by up to 0.5 – 0.75 m during the monitoring period. This relatively small seasonal fluctuation is less than is often observed in sand and gravel aquifers. The low amplitude of fluctuations is likely due to the expected high porosity (and therefore specific yield) of the sands and gravels, but also could be due to little seasonal variability in rainfall during the period (see Table 12.6).
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12.3.46 Groundwater levels are generally lower in summer and higher in winter but, being so shallow, the aquifer appears to respond rapidly to rainfall, and peaks can occur at any time of year. The rapid response to rainfall occurs due to the relatively thin and permeable topsoil layer that overlies the sand and gravel aquifer. Groundwater levels show a recent rise between September 2019 and January 2020 due to the high incident rainfall over this period.
12.3.47 Groundwater contours for August 2019, representing a recent summer high in groundwater levels, are shown in Figure 12.11. Groundwater flow is eastwards towards the River Trent, in the same direction as flow in Drain A and the Pyford Brook. A survey from September 2019 (Cemex Drawing ALS SITE OGL BH Hydro & Servs 0919 rjj) shows that water levels in Drain A and Pyford Brook are similar to the groundwater contours and suggests that these watercourses are in hydraulic continuity with the groundwater. The groundwater contours presented in Figure 12.11 have been drawn based on these water level data.
12.3.48 Groundwater contours indicate that the Pyford Brook and Drain A are gaining along their reaches as they pass the Application Site. This is expected to be the dominant, prevailing condition throughout much of the year. It is likely that during flood events, surface water levels would be higher than groundwater levels and the watercourses would lose to groundwater. The low amplitude of the temporal groundwater variation suggests that the Pyford Brook and Drain A buffer seasonal variations in groundwater level.
12.3.49 Lithological descriptions of the Gunthorpe Member from on-site borehole logs suggest that this unit will likely behave as an aquitard and will form the base of the sand and gravel aquifer. Based on lithological descriptions, it is unlikely that there will be any significant groundwater flow between the sand and gravel and Mercia Mudstone Group strata. The presence of the Mercia Mudstone Group will isolate the much deeper Sherwood Sandstone Group from the sand and gravel aquifer.
Aquifer Properties
12.3.50 The sand and gravel aquifer at the Application Site is typically a sandy gravel or gravelly sand, containing variable proportions of clay. Therefore, it is expected to have a high hydraulic conductivity of up to 100 m/day.
12.3.51 Values for the hydraulic conductivity have been indirectly estimated based on particle size distributions, and geological descriptions presented in (Geotechnics, 2017) An
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approximate estimation of permeability from particle size distributions can be obtained using Equation 1 after (Hazen, 1893):
= ∙ (1)
Where:
k is hydraulic conductivity (m/s);
D10 is the grain size at which 10% of particles in the sample are retained (mm); and
C is an empirical correlation factor.
12.3.52 A C value of 0.01 is typically used when grain size is in millimetres and hydraulic conductivity in m/s. Values derived from Equation 1 should be treated with caution, because they do not account for inherent heterogeneity or anisotropy (bedding planes, silty areas etc.) that might be present in the aquifer. The formula is also generally only
applicable where D10 is in the range of 0.1 – 3 mm. Values estimated here should therefore be treated as an approximate guide.
12.3.53 Table 12.12 presents results of the analysis. Where the D10 value exceeds 3 mm, the equation is considered inappropriate and no estimate has been made. Estimated hydraulic conductivity values range from 17 – 553 m/day. Estimates are higher where the mineral is described as “sandy gravel” and lower where clay is present in the matrix.
12.3.54 Although Equation 1 has yielded values consistent with those expected for a sand and gravel aquifer, there is likely to be some error in the results. Basing permeability on grain size alone does not account for macro scale heterogeneity in the aquifer that could influence the hydraulic conductivity. The result of 553 m/day is an outlier and therefore a representative maximum has been taken as the 95th percentile (106 m/day). A representative minimum has been assumed as the 25th percentile (33 m/day) and the mean (removing the lowest and highest results) of 69 m/day is considered as the best estimate of the aquifer as a whole.
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Table 12.12 Hydraulic conductivity estimates from particle size distributions presented by (Geotechnics, 2017)
Hydraulic
Borehole Depth interval (m) D10 (mm) Description Conductivity (m/day) 2 - 2.5 0.4 Sandy gravel 138 CP12/17 6 - 6.5 0.14 Gravelly, slightly clayey sand 17 10.5 - 11 0.18 Slightly clayey sand and gravel 28 2.5 - 3 0.25 Very gravelly, slightly clayey sand 54 CP13/17 9 - 9.5 0.16 Gravelly, slightly clayey sand 22 12.5 - 13 0.19 Very sandy slightly clayey gravel 31 WM01-17 7 - 7.5 4 Sandy gravel n/a 1.5 - 2 0.18 Very gravelly, slightly clayey sand 28 WM02-17 3 - 3.5 5 Sandy gravel n/a 7 - 7.5 0.28 Very gravelly, slightly clayey sand 68 WM03-17 2 - 2.5 0.31 Very sandy gravel 83 7.1 - 7.6 0.14 Gravelly, slightly clayey sand 17 WM04-17 9 - 9.5 0.32 Very sandy gravel 88 2.5 - 3 0.3 Very sandy, slightly clayey gravel 78 WM05-17 7 - 7.5 0.35 Very sandy, slightly clayey gravel 106 5 - 5.5 0.26 Very sandy gravel 58 WM06A-17 9.5 - 10 0.35 Very sandy gravel 106 4.5 - 5 0.8 Sandy gravel 553 WM07-17 7 - 7.5 0.43 Sandy, slightly clayey gravel 160 2 - 2.45 0.21 Slightly clayey sand and gravel 38 8 - 8.5 0.31 Very sandy gravel 83 WM12-17 12 - 12.5 0.25 Slightly gravelly, slightly clayey sand 54 15 - 15.5 3 Sandy gravel n/a 2 - 2.45 0.3 Very sandy gravel 78 WM09-17 6.5 - 7 0.26 Very sandy, slightly clayey gravel 58 WM11-17 2.5 - 3 0.3 Very sandy gravel 78
12.3.55 The aquifer layers with the Gunthorpe Member are typically not laterally extensive and transmissivity has a geometric mean of 12.3 m2/day (Jones, et al., 2000)).
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Fluvial Flood Risk (Flood zones)
12.3.56 The EA’s Flood Zones for Planning, indicating flood risk from rivers and the sea, are shown in Figure 12.12 (Environment Agency, 2019). The EA has defined three flood zones as follows:
Flood Zone 3: the extent of a flood from rivers with a 1% (1 in 100) chance or greater of happening in any given year.
Flood Zone 2: the extent of a flood from rivers or from the sea with up to a 0.1% (1 in 1000) chance of happening in any given year.
Flood Zone 1: the extent of a flood from rivers or from the sea with a less than 0.1% (1 in 1000) chance of happening in any given year.
12.3.57 The Application Site is located mainly within Flood Zone 1. Areas adjacent to the southern boundary are in Flood Zones 2 and 3 associated with the Pyford Brook, and there is a small area in the north-west of the Application Site in Flood Zone 2, associated with Drain A. Regionally, there are extensive areas of Flood Zone 3 existing to the north and east associated with the River Trent and River Tame respectively.
12.3.58 East of the Application Site, the areas of Flood Zone 2 and Flood Zone 3 associated with the Pyford Brook become spatially more extensive. This is thought to be caused by backing up from culverts further east as the watercourse passes beneath a minor road and the A513. It may also be related to the increased density of watercourses as a number of watercourses and drains (including Drain A) converge towards their confluence with the River Trent.
12.3.59 The Sequential Test, outlined in the PPG identifies that development should be directed to areas at the lowest probability of flooding (Department for Communities and Local Government, 2014). The proposed land use is classified as Water Compatible and as such is deemed an appropriate development in Flood Zones 1 to 3 (see Table 12.13).
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Table 12.13 Flood risk vulnerability and flood zone compatibility
Flood risk Essential Water More vulnerability Highly vulnerable Less vulnerable infrastructure compatible vulnerable classification Zone 1 ✓ ✓ ✓ ✓ ✓ Exception Test Zone 2 ✓ ✓ required ✓ ✓ Exception Test Exception Test Zone 3a x required ✓ required ✓ Zone 3b Exception Test Flood zone Flood functional x x x required ✓ floodplain
✓Development is appropriate. x Development should not be permitted. Data source: National Planning Policy Guidance (NPPG) (Department for Communities and Local Government, 2014)
Flood Defences
12.3.60 Based on EA mapping, there are no flood defences or areas benefitting from flood defences in and around the Application Site (Environment Agency, 2019). There are also no designated flood storage areas, where water has to be stored in times of flood, in and around the Application Site.
Historical Flooding
12.3.61 Flood mapping included as part of the Local Level 1 Strategic Flood Risk Assessment indicates that there is no recorded historical flooding at the Application Site, from artificial drainage, dam burst fluvial, highways, sewers, surface water or other unknown sources. The EA’s historical flood map (Environment Agency, 2019) also shows that there are no recorded historical flood events that have affected the Application Site.
12.3.62 During a site visit undertaken by the Applicant in March 2015, debris was observed on the central part of the northern (true left) bank of the Pyford Brook. This debris was present up to approximately 2 m from the Pyford Brook and is thought to indicate the maximum extent of a flood event. Rainfall data from the Lichfield rain gauge shows that 70 mm of rain fell in March 2015, with one day (23 March) showing 18 mm of rainfall. March 2015 was the 57th wettest month in the 18 year record, but was approximately 50% wetter than the March average.
12.3.63 The March 2015 flood event may have been caused by a flashy response to high intensity rainfall. However, anecdotal evidence from the farmer suggests that peaks in the Pyford Brook flow coincide with discharge from the South Staffordshire Water sewage treatment
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works. The sewage treatment works are located 2.5 km south-west of the Application Site, just upstream of the confluence between the Full Brook and Curborough Brook. This is a daily discharge, and it is considered likely that this discharge would only contribute to flooding if flows in the watercourse were already high.
12.3.64 On 19 February 2020, three days after Storm Dennis, photographs were taken by the Applicant of agricultural land immediately south of the Application Site (on the true right bank of the Pyford Brook). A photograph is provided in Appendix 5.7. Although, the watercourse was not in flood at this time, sand deposits across the field in the foreground of the photograph provides evidence of flooding. Given the similar elevations of land at the Application Site, it is possible that the Application Site would also have experienced some flooding in the days prior to the photographs being taken. Appendix 5.7 indicates that there is a raised bank present along the southern edge of the Site and this may have caused the flooding to be localised to areas where the raised bank is lowest.
Surface Water (Pluvial) Flooding
12.3.65 Surface water (pluvial) flooding is usually associated with extreme rainfall events but may also occur when rain falls on land that is already saturated or has a low permeability. Rainfall that is unable to infiltrate into the ground generates overland flow which can lead to flooding or ‘ponding’ in localised topographical depressions before the runoff is able to enter the drainage system or watercourse.
12.3.66 The EA has characterised pluvial flood likelihoods from very low to high, as follows:
High: the likelihood of flooding with a greater than 1 – 3.3% (1 in 30) chance of happening in any given year.
Medium: the likelihood of flooding with a 1 – 3.3% (1 in 30) chance of happening in any given year.
Low: the likelihood of flooding with a 0.1 - 1% (1 in 100) chance of happening in any given year.
Very Low: the likelihood of flooding with a less than 0.1% (1 in 1000) chance of happening in any given year.
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12.3.67 The risk of surface water flooding has been obtained from the EA web map service (Environment Agency, 2019) For the majority of the Application Site, the risk of pluvial flooding is very low with less than a 0.1% annual chance of flooding (see Figure 12.13). There are small areas of the Application Site with a 0.1% chance of flooding from surface water. There are isolated areas within the Application Site with low, medium and high flood risks. These are associated with low-lying areas and areas with depressions and hollows for surface water to pond, particularly around the Pyford Brook and Drain A. There are extensive areas of pluvial flood risk to the west of the Application Site associated with Drain A.
Groundwater Flooding
12.3.68 Groundwater flooding occurs when the water table rises above the ground surface or into man-made ground. Groundwater level hydrographs suggest that groundwater levels typically do not naturally rise above ground surface (minimum water depths reach 0.1 m below ground level in the northern and central part of the Application Site). However, levels do get close to ground surface and following periods of prolonged rainfall, this could lead to flooding.
12.3.69 The 2014 Level 1 Strategic Flood risk assessment indicates that the entire Application Site is susceptible to groundwater flooding above surface level (Capita, 2014). Based on this and the above, the risk of groundwater flooding could be high.
Flooding in the Event of Reservoir Failure
Figure 12.14 indicates that more than half of the Application Site is at risk of flooding in the unlikely event of reservoir failure (Environment Agency, 2019). This predicted flooding would occur along the Pyford Brook should Stowe Pool in Lichfield be breached. Where flooding as a result of reservoir failure is predicted to occur, the depth of flooding is expected to be less than 0.3 m, except in a few isolated areas where the flooding depth is expected to be between 0.3 m and 2 m of water. Given the flat topography across the Application Site, it is expected that these few areas have a modelled flood depth much closer to 0.3 m than to 2 m.
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Surface Water Quality
12.3.70 Surface water quality data has been provided by the EA for three sampling points along the Pyford Brook (also known as Curborough Brook to the south of the Trent & Mersey Canal). These sampling locations are shown in Figure 12.15 and a summary of this data is provided in Appendix 5.4. Iron and manganese concentrations were measured at one sample location (Pyford 1). Iron concentrations exceed the Environmental Quality Standard (EQS) limit of 1 mg/l in 1 of 20 samples and manganese does not exceed the EQS limit of 0.123 mg/l in any samples. Nitrate and nitrite were monitored at all locations and exceed the UKDWS in 26% and 63% of samples respectively. These data indicate that the water quality is generally good with some exceedances of nitrogen species which are typical in a watercourse of this type in an agricultural area.
Groundwater Quality
12.3.71 Groundwater quality monitoring in the shallow sand and gravel aquifer has been carried out by the Applicant monthly from May to July 2019 in all ten piezometers. A statistical summary of these results compared with UK Drinking Water Standards (UKDWS) is given in Appendix 5.5.
12.3.72 Water quality in the sand and gravel aquifer is generally good, with only iron and manganese exceeding the UKDWS. The mean iron concentration is 0.92 mg/l with a range of <0.23 to 0.92 mg/l, against the UKDWS standard of 0.2 mg/l. Only 5 of 30 samples exceeded the detection limit and these samples were taken from WOB01, WOB02 and WOB03, located on the western upgradient boundary of the Application Site.
12.3.73 Manganese concentrations are greater than the UKDWS in all samples with a mean of 0.288 mg/l and a range of 0.099 to 0.656 mg/l. Elevated iron and manganese concentrations are typical in groundwater.
12.3.74 Groundwater quality data was provided by the EA for Fradley Boreholes No 1 and No 2 which are thought to be screened in the lower Mercia Mudstone Group and upper Sherwood Sandstone Group and not the sand and gravel aquifer. Given the hydraulic separation between these units, these data are not considered in detail here.
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Licenced Surface Water Abstractions
12.3.75 The EA provided details of licenced surface water and groundwater abstractions in September 2019. There are 29 licenced surface water abstractions within 4 km of the Application Site; 11 licenced surface water abstractions from point locations and 18 abstraction reaches along watercourses, as shown in Figure 2.16 and summarised in Table 12.14 and Table 12.15.
12.3.76 The majority of abstractions are used for direct spray irrigation on agricultural land. There are also abstractions for mineral processing and transfer to ponds or lakes. The reach of the Pyford Brook that borders the Application Site is utilised for an abstraction by Hall Farm for spray irrigation (SWR8) and Alrewas Farm (SWR45 and SWR15).
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Table 12.14 Licenced abstractions from surface water point sources
Operator/ Distance from Permitted daily Permitted annual ID Licence ID Use Location Application Site abstraction (m3) abstraction (m3))
SW7 600 m north Agriculture - Spray Irrigation - Direct 03/28/07/0078 Hall Farm 1,182 80,000 Agriculture - Transfer Between Sources (Pre SW8 860 m north-east Water Act 2003)
Needwood House SW6 03/28/07/0056 720 m east Agriculture - Spray Irrigation - Direct 1,440 60,000 Farm
Environmental - Transfer Between Sources (Post SW11 MD/028/0007/001 Yeatshall Farm 1.3 km north-west Not specified Water Act 2003)
SW2 1.4 km west
SW5 1.5 km west Common Lane 03/28/07/0040 Agriculture - Spray Irrigation - Direct 981 15,911 Farm SW4 1.7 km west
SW3 1.8 km west
9,000 SW9 03/28/07/0089 Wood End Farm 2.3 km south-west Agriculture - Spray Irrigation - Direct 500
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Operator/ Distance from Permitted daily Permitted annual ID Licence ID Use Location Application Site abstraction (m3) abstraction (m3))
Canal and River SW10 03/28/22/0030 2.4 km south Agriculture - Spray Irrigation - Storage 155 13,640 Trust Hanson Quarry SW1 03/28/05/0039 Products Europe 3.4 km west Mineral Washing 4,546 1,059,000 Ltd
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Table 12.15 Licenced abstractions from surface water reaches
Permitted Permitted Abstraction Distance from daily annual ID Location Source Use Description Licence Number Application Site abstraction abstraction (m3) (m3)) Agriculture - Spray SWR4 03/28/07/0056 Alrewas Farm Pyford Brook Immediately south 1,440 60,000 Irrigation - Direct Agriculture - Spray SWR15 03/28/07/0102/R01 Alrewas Farm Pyford Brook Immediately south 960 40,000 Irrigation - Direct Pyford Brook (Points SWR8 Immediately south A & B) Bourne Brook SWR9 850 m north-west (Points E & F) Agriculture - Spray 03/28/07/0078 Hall Farm Orgreave 1,182 80,000 Bourne Brook Irrigation - Direct SWR11 950 m north (Points C & D) River Trent (Points SWR10 1.1 km north-west G & H) Land At Sale Lane & Hayend Tributary of River Agriculture - Spray SWR19 03/28/22/0092/R01 500 m south 689 7,886 Lane Alrewas Tame Irrigation - Direct Canal And River Trust - Fradley Agriculture - Spray SWR18 03/28/22/0068 Coventry Canal 920 m south 1,000 10,230 Junction Irrigation - Direct Tributary of River Agriculture - Spray SWR17 03/28/22/0058 Land At Alrewas 1.1 km south-east 184 2,114 Tame Irrigation - Direct Agriculture - Spray SWR6 03/28/07/0072 Manor Farm, Alrewas River Trent 1.2 km north-east 818 22,730 Irrigation - Direct Agriculture - Spray SWR14 03/28/07/0101/R01 Overley Farm, Alrewas River Trent 1.2 km north-east 2,400 90,000 Irrigation - Direct Agriculture - Spray SWR5 03/28/07/0063 Blakenhall Park, Staffs River Swarbourn 1.6 km north 3,500 120,000 Irrigation - Storage Agriculture - Spray SWR1 03/28/07/0037 Woodgate Farm Bourne Brook 1.6 km west 582 23,275 Irrigation - Direct New Buildings Farm, Kings Agriculture - Spray SWR12 03/28/07/0083 River Trent 2 km north-west 675 15,000 Bromley Irrigation - Direct Lake & Pond Throughflow SWR13 03/28/07/0100/2 Curborough Hall Farm - Curborough Brook 2.9 km south-west 347 31,250 Make-Up Or Top Up Water
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Permitted Permitted Abstraction Distance from daily annual ID Location Source Use Description Licence Number Application Site abstraction abstraction (m3) (m3)) SWR2 River Trent 3.1 km north-west Agriculture - Spray 03/28/07/0053 Near King's Bromley Tributary of River 195 6,819 SWR3 3.6 km north-west Irrigation - Direct Trent Agriculture - Spray SWR7 03/28/07/0073 Wychnor Bridges Farm River Trent 3.5 km east 2,728 136,380 Irrigation - Direct Agriculture - Spray SWR16 03/28/22/0040 Sittles Farm, Fradley River Tame 3.5 km south-east 682 100,000 Irrigation - Direct
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Licenced Groundwater Abstractions
12.3.77 There are eight licenced groundwater abstractions within the study area. These are summarised in Table 12.16 and shown in Figure 2.17. Most abstractions are utilised for agricultural purposes. The closest abstraction (GW6) is operated by Wilson Bowden Developments Ltd from a lagoon and is used for spray irrigation purposes.
12.3.78 The Application Site is not in a Source Protection Zone (SPZ). The closest SPZ is a small area of Zone 1 around Fradley Pumping Station close to the junction of Ironstone Lane and the Coventry Canal. This SPZ is approximately 230 m in diameter and 2.9 km south of the Application Site. The boreholes at this location are over 70 m deep (ref: Planning document) and are therefore likely to be abstracting from the sandstone units of the Upper Sherwood Sandstone Group.
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Table 12.16 Licenced groundwater abstractions within the study area
Permitted Permitted daily annual ID Licence ID Operator Distance Use Source abstraction abstraction (m3) (m3))
Wilson Bowden 1.1 km Agriculture - Spray GW6 03/28/22/0091/R01 Developments Groundwater 873 15,000 south Irrigation - Direct Limited
2 km north- General Farming & GW3 03/28/07/0008 Common Lane Farm Groundwater 27 9,956 west Domestic
2.2 km GW1 north-west Agriculture - Spray 03/28/07/0002 Woodshoot Farm Groundwater 937 113,468 Irrigation - Direct 2.3 km GW2 north-west 2.7 km Agriculture - Spray GW7 MD/028/0007/007 P D Nurseries Groundwater 80 10,000 north-west Irrigation - Direct Mineral Washing Tarmac Trading 2.9 km GW4 03/28/22/0070 Dust Suppression Groundwater 5,214 1,548,750 Limited east Process Water
South Staffordshire Potable Water GW5 03/28/22/0081 3 km south Groundwater 12,000 3,650,000 Water Plc Supply - Direct
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Private Water Supplies
12.3.79 Lichfield District Council confirmed in August 2019 that there are two known private, deregulated abstractions (< 20 m3/day) within 4 km of the Application Site. Details of these are outlined in East Staffordshire District Council responded in October 2019 to advise that it holds no records of private water supplies.
12.3.80 Table 12.17 and Figure 2.17 shows the locations. The closest abstraction to the Application Site is at Fradley Marina, a new development 260 m to the south. Water from this abstraction is used for domestic purposes.
12.3.81 East Staffordshire District Council responded in October 2019 to advise that it holds no records of private water supplies.
Table 12.17 Private abstractions in Lichfield District within 4 km
Abstraction rate Distance from Location Source Water use (m3) Application Site Commercial marina Fradley Marina Borehole Not known providing water for 260 m south domestic purposes Commercial Crematorium, water Lichfield and District Borehole Not known used for domestic 2.3 km south-east Crematorium purposes including drinking
Designated Sites
12.3.82 The closest designated sites are the River Mease SSSI located 4.2 km east of the Application Site and the Christian Fields Local Nature Reserve located 4.4 km south-west of the Application Site on the outskirts of Lichfield. The River Mease SSSI is designated for its populations of two internationally notable species of native freshwater fish.
12.3.83 The Fradley Pool Nature Reserve is 600 m to the south and is a Site of Biological Importance (SBI) also known as a Local Wildlife Site (LWS). This is a local non-statutory designation used by Staffordshire County Council. Figure 12.18 shows the location of this site.
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Hydrogeological Conceptual Model
12.3.84 Figure 12.19 shows a conceptual hydrogeological cross section running approximately east-west through the Application Site. The cross section is based on available geological data and the conceptual understanding of the Application Site. This section summarises the hydrogeological conceptual model.
12.3.85 The economic mineral at the Application Site is the superficial deposits of the Holme Pierrepont Sand and Gravels. These are between 8.7 and 15 m thick at the Application Site. Drilling at Application Site indicates the sand and gravels are fine to coarse sub- angular to sub-rounded gravels of mudstone and quartzite, commonly with fine to coarse sands. The sand and gravel mineral is set within a matrix variably described as clayey to sandy. The underlying bedrock is the Gunthorpe Member of the Mercia Mudstone Group which is described as a red mudstone.
12.3.86 The sand and gravel aquifer is a Secondary A aquifer. The Gunthorpe Member of the Mercia Mudstone Group is a Secondary B aquifer. Beneath the Application Site the Gunthorpe Member is comprised of mudstone and so is therefore considered to represent the base of the sand and gravel aquifer with little hydraulic connectivity between the two units. The Gunthorpe Member will hydraulically isolate the sand and gravel from the underlying Sherwood Sandstone Group aquifer.
12.3.87 Groundwater level monitoring at the Application Site indicates a shallow water table of approximately 0.1 – 1.5 m below the ground surface. Groundwater levels indicate a shallow gradient with groundwater flow towards the east, following the direction of Drain A and the Pyford Brook. Groundwater levels respond rapidly to rainfall and this, together with the geologically description, indicates that rainfall-recharge will be the main source of recharge to the aquifer. Regionally, groundwater flows towards the River Trent to the north and east. Groundwater in the sand and gravel primarily discharges to the River Trent but locally will discharge to neighbouring surface water features, including Drain A and the Pyford Brook and neighbouring unlined surface waterbodies.
12.3.88 Water levels in Drain A and the Pyford Brook are similar to the groundwater levels indicating that these watercourses are hydraulically connected and likely gaining from groundwater. This is expected to be the prevailing condition however, they may lose to groundwater during times of flood.
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12.3.89 Groundwater quality is generally good, with elevated iron and manganese concentrations as is typical for groundwater. Surface water quality is also generally good, with elevated concentrations of nitrate and nitrite, typical of watercourses in agricultural areas.
12.3.90 There are no designated sites within the 4 km study area. The Fradley Pool Nature Reserve has a local non-statutory designation of SBI and LWS and is located 600 m to the south- west and upstream of the Application Site. As this pool was constructed as a reservoir for the canal, it is presumed to be lined and therefore not susceptible to changes in the groundwater level.
12.4 Embedded Mitigation
12.4.1 Overburden will be used to line the southern faces of each quarry void. This will be undertaken to minimise ingress of water to the voids from the Pyford Brook.
12.4.2 Settlement ponds will be used to facilitate the settlement of entrained silt/clay prior to discharge to the Pyford Brook via an outlet. Water would be transferred from the quarry void to a series of settlement lagoons that would ultimately drain to a freshwater lagoon prior to discharge off-site. This will clarify the water prior to discharge from the Application Site. All off-site discharge will be undertaken in accordance with a discharge permit (to be obtained).
12.4.3 Re-infiltration of water from the settlement lagoon system to the sand and gravel aquifer will occur. This will replace some of the water lost from the aquifer by dewatering and mitigate impacts on groundwater-dependent receptors.
12.4.4 Runoff from the Application Site will be directed to the quarry void to allow attenuation prior to discharge off-site. Upon restoration, the restored lakes will provide additional attenuation capacity reducing peak runoff rates and associated flood risk. Further details of this are presented in Appendix 5.7.
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12.5 Likely Significant Environmental Effects
Potential receptors
12.5.1 This section highlights potential receptors that have been identified in the baseline report section. The primary receptors in the study area, which are detailed in the baseline section and could potentially be influenced by the Proposal are:
Pyford Brook;
Drain A;
Other water features within the study area (except the canals which are understood to be lined);
Neighbouring licenced abstractions and private water supplies; and
Fradley Pool Nature Reserve and SBI.
Dewatering Requirements
12.5.2 Quarry void dewatering would include groundwater inflows and surface water ingress (comprising runoff and rainfall components). At the Application site the groundwater component will be the main component of the total required dewatering rate.
12.5.3 Appendix 5.6 contains an assessment of dewatering rates from surface water and groundwater ingress into the quarry void. Based on this assessment, a best estimate of total dewatering rate is 17,035 m3/day (197 l/s). This could be much greater during storm events. This activity would require a transfer licence. Water would be transferred to a series of settlement ponds that would flow to a freshwater lagoon.
12.5.4 A proportion of the water would be pumped from the freshwater lagoon to be utilised for various purposes at the quarry including dust suppression and mineral processing. This proportion would require a full abstraction licence.
12.5.5 Appendix 5.6 estimates a radius of influence of up to 700 m. from the excavation areas. This is an oversimplification and the radius of influence will be reduced to the south by the buffering influence of the Pyford Brook and lined southern faces of the active excavation.
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General Effects of the Proposal
12.5.6 The array of potential significant effects from quarrying activities associated with sand and gravel extraction are well understood. A well-designed quarry and standard mitigation measures can avoid many of these likely significant effects.
12.5.7 Table 12.18 lists potential significant effects and the typical mitigation measures applied.
Table 12.18 Potential Effects of quarrying activities and typical mitigation measures
No. Type of Impact Typical Mitigation Measures
A Impacts from dewatering through lower groundwater levels in surrounding aquifer units.
A1 Impacts on water levels in nearby abstractions. Impacts on habitats sensitive to shallow A2 groundwater levels. Impacts on water levels in any nearby ponds and A3 lakes in connection with the aquifer. Avoid working nearby, cut off walls, recharge trenches, discharge of compensation flows to Impacts on baseflows in drains and watercourses A4 drains. sourced from sand aquifer.
Impacts on neighbouring buildings and A5 infrastructure caused by drawdown related settlement.
B Impacts from quarry operation
Settlement lagoons, standard planning Impacts on groundwater and surface water quality B1 conditions regarding bunding of fuel tanks, from standard plant operation. appropriate spill response procedures etc.
C Impacts from discharge of water from dewatering operations Settlement lagoons, controlled by discharge C1 Impacts on receiving drain water quality. permit to be applied for. Attenuate any additional flows created prior to C2 Impacts on receiving drain water flows. discharge at no more than the greenfield rate. Diversion of baseflow from one catchment to Relocation of discharge point, discharge of C3 another. compensation flows to drains.
D Impacts from restoration
Long term impact on groundwater levels (can be Appropriate design of restoration, particularly D1 either increased or decreased depending on the materials used to restore slopes and the restoration scheme design). level and location of the overflow point. Additional loss of water from open water Reduce areas of open water in restoration D2 evaporation. concept.
SuDs style overflow channels to minimise peak D3 Faster runoff and increased flood risk. flows.
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12.5.8 In the following sections the potential for the general hydrogeological impacts listed in
12.5.9 Table 12.18 to apply to the receptors identified above is discussed for the Proposal. In accordance with Table 12.3, where the significance of impact is Major/Moderate or more, the impact is considered significant and mitigation measures have been proposed in the following section.
12.5.10 This section looks at distance from the excavation areas (i.e. where dewatering would be occurring) rather than distance from the Application Site.
A Effects from dewatering through lower groundwater levels in surrounding aquifer units.
A1 Neighbouring Abstractions
12.5.11 Neighbouring abstractions within the 700 m radius of influence of the excavation areas are given in Table 12.19. There are four licenced surface water abstraction reaches and one private water supply abstraction within 700 m of the excavation areas. All abstractions are utilised for various agricultural or domestic supply purposes and are conservatively considered as medium sensitivity receptors.
12.5.12 The private water supply at Fradley Marina (sourced from a borehole) is 300 m south of the eastern excavation area and 640 m from the western extraction area. Discharge from the settlement lagoon system to the Pyford Brook during dewatering and the lining of the southern face of the quarry voids will buffer drawdown effects to the area south of the Pyford Brook.
12.5.13 Due to this buffering effect, drawdowns at SWR19 and the Fradley Marline private water supply to the south of the Pyford Brook are expected to be negligible and the level of effect is therefore neutral at these receptors. SWR8 lies within the reach of the Pyford Brook to which water will be discharged and there will similarly be negligible impacts on this receptor and the level of effect will be neutral.
12.5.14 SWR4 and SWR15 abstract from reaches of the Pyford Brook upstream of the Application Site. This is upstream of the proposed discharge point and drawdown could effect this reach close to the Application Site. Effects will, in part, be mitigated by the use of low permeability overburden to line the walls of the quarry void. However, impacts could still
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be moderate on both of these abstractions (SWR4 and SWR15), giving rise to a moderate level of effect. Effects could be significant and mitigation measures have therefore been proposed.
12.5.15 As discharge from dewatering would supplement flows in the Pyford Brook, SW6 (located 750 m downstream from the eastern excavation area) will not be adversely affected by the Proposal. The level of effect on all other neighbouring abstractions is expected to be neutral.
Table 12.19 Summary of receptors with potential effect from the Application Site
Distance from Magnitude of Location Name Sensitivity Level of effect excavation areas impact Hall Farm SWR8 Orgreave – 35 m south Medium Negligible Neutral Pyford Brook
Alrewas Farm – SWR4 80 m south-west Medium Moderate Moderate Pyford Brook
Alrewas Farm – SWR15 80 m south-west Medium Moderate Moderate Pyford Brook
Private -- abstraction at 300 m south Medium Negligible Neutral Fradley Marina
Land At Sale Lane & Hayend SWR19 Lane Alrewas - 550 m south Medium Negligible Neutral Trib Of River Tame
A2 Effects on habitats sensitive to shallow groundwater levels
12.5.16 There are no designated sites within the 700 m radius of influence. The closest designated site is the River Mease SSSI located 4.2 km west of the Application Site. Given the distance to this receptor, the level of effect is expected to be neutral. The Fradley Pool Nature Reserve is an SBI/LWS (non-statutory designation) and is located 630 m to the south-west of the western excavation area. This site is conservatively considered as a medium sensitivity receptor. The main water-dependent feature is a pool that was originally built as a reservoir and is therefore presumed to be lined. Given this, the distance from the
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excavation area and that the impacts on groundwater levels to the south of the Pyford Brook will in part be buffered by the discharge to Pyford Brook, the impact due to dewatering is expected to be negligible and the level of effect is assessed as neutral.
A3 Effects on water levels in any nearby ponds and lakes in connection with the aquifer
12.5.17 There are four waterbodies within the 700 m radius of influence. These are summarised in Table 12.20. The cone of drawdown will spread westwards because this is upgradient of the proposed discharge to the Pyford Brook and the effect of lining the southern faces of the quarry voids will offer only minimal buffering capacity in this direction.
12.5.18 Ponds at Alrewas Hayes Cottages (WB11) are the closest receptor, located 370 m south- west of the excavation area. These ponds are considered to be a low sensitivity receptor. The magnitude of impact could be moderate at this receptor producing a minor level of effect. Effects on these ponds could be limited if they have any low permeability sediment that comprises the bed or are lined. Impacts will be much less from working the eastern void. This is because of the greater distance from the receptor, the lower anticipated radius of influence and that infiltration from the freshwater lagoon will buffer drawdown impacts to the west.
12.5.19 The level of effect on all other neighbouring waterbodies is predicted to be neutral. This is due to the distance from the excavation area and low sensitivity of the receptors. Impacts could be slight on the linear pond at the belt (WB4) and the pond south of Alrewas Hayes Cottages (WB3).
Table 12.20 Summary of potential impacts to nearby waterbodies
Distance from the Magnitude of ID Name Sensitivity Level of effect excavation area impact
Small ponds at Alrewas WB11 370 m south-west Low Moderate Minor Hayes Cottages
Linear pond and ditch at The WB4 530 m west Low Slight Neutral Belt Pond south of Alrewas WB3 560 m south-west Low Slight Neutral Hayes Cottages Fradley Pool Nature Reserve WB1 630 m south Medium Negligible Neutral (presumed lined)
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A4 Effects on baseflows in drains and watercourses sourced from the sand and gravel aquifer
12.5.20 There are four watercourses within 700 m of the Application Site, and these are listed in Table 12.21. The Pyford Brook will receive water from the outfall from the freshwater lagoon and this will maintain flows in the brook downstream of the discharge point. Furthermore, the lining of the southern faces of the quarry voids will buffer drawdown impacts on the brook. However, dewatering will intercept baseflows to the Pyford Brook and there could be impacts on the brook upstream of the Application Site (up to the radius of influence) and in the reach adjacent to the Application Site upstream of the discharge point. These impacts could be moderate, and this could yield a moderate level of effect on this receptor. Mitigation measures are therefore required.
12.5.21 Drain A will not receive dewatering water and, given that it is connected to the sand and gravel aquifer, flows will likely be depleted and/or intercepted by the dewatering. This will likely lead to reduced flow within the radius of influence and downstream to the confluence with the Pyford Brook. There are no abstractions from Drain A, it is ephemeral and is of limited ecological value. It is therefore considered to be a low sensitivity receptor. The predicted impact is substantial but this would have only a moderate/minor effect and therefore mitigation measures are not required.
12.5.22 The Trent & Mersey Canal is presumed to be lined and therefore the potential magnitude of impact is negligible. Feature WCH (see Figure 12.16) is located 575 m from the excavation area on the opposite side of the Pyford Brook to the Application Site. It is expected that the Pyford Brook will buffer the effects of drawdown in this direction. Given the distance from the excavation area and this buffering effect, the magnitude of impact is considered to be negligible and the level of effect is neutral. The magnitude of impact on other watercourses (including various neighbouring agricultural drainage features) within the study area will similarly be negligible and the level of effect on these watercourses will be neutral.
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Table 12.21 Watercourses within the radius of influence
Distance from the Magnitude of Location Name Sensitivity Level of effect excavation area impact
WCB Pyford Brook 30 m south Medium Moderate Moderate WCA Drain A 35 m north Low Substantial Moderate/Minor Trent & Mersey WCJ 240 m south Medium Negligible Neutral Canal Watercourse WCH between the Sale 535 m south Low Negligible Neutral and Alrewas
A5 Effects on neighbouring buildings and infrastructure caused by drawdown related settlement
12.5.23 Buildings and other infrastructure could be susceptible to settlement if groundwater levels within compressible strata are depressed beyond their normal range. The most proximal receptors are three underground gas pipelines that cross the Application Site. These pipelines are expected to be within 2 - 3 m of the ground surface, and hence could be within the sand and gravel aquifer. Other receptors lying within the radius of influence are the various farms, houses and commercial premises surrounding the Application Site. All are identified as highly sensitive receptors.
12.5.24 The sand and gravel aquifer at the Application Site has a low clay content and is overlain by a relatively thin overburden. The sand and gravel is expected to be effectively incompressible meaning settlement would not be expected from dewatering of this unit alone. The overburden is typically described as “slightly gravelly and slightly clayey sand” based on this description it is likely that this unit too is similarly largely incompressible. Given this and that groundwater levels suggest that the overburden has become unsaturated during the monitoring period due to natural water table fluctuation, the risk of settlement at all receptors from dewatering is considered negligible. The level of effect is therefore neutral.
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B Effects from quarry operations
B1 Effects on groundwater and surface water quality from standard plant operation
12.5.25 Water quality could be affected by chemical spillage or mobilisation of suspended solids. Groundwater quality sampling at the Application Site indicates that the groundwater quality of the sand and gravel aquifer is generally good. Since the aquifer is used for groundwater abstraction, the sensitivity is considered to be high.
12.5.26 Spills at the Application Site could feasibly occur through the accidental loss of fluids from mobile and/or fixed plant equipment. Given that groundwater in the sand and gravel aquifer would be directly affected by any spill, the magnitude of impact is considered to be substantial and the level of effect is therefore major. Effects are therefore considered to be potentially significant and mitigation measures are therefore proposed to mitigate effects.
12.5.27 Contaminated groundwater could also flow to neighbouring watercourses. Groundwater is in hydraulic continuity with watercourses in this area, including Drain A and the Pyford Brook. However, dewatering would cause the hydraulic gradient to be reversed (i.e. to become from the watercourses towards the aquifer). Contaminated groundwater will therefore not be able to enter the watercourses from the aquifer but could be discharged to the Pyford Brook. In this scenario, dilution from natural river flow, means the magnitude of impact is deemed to be moderate and therefore the level of effect is predicted to be moderate on these medium sensitivity receptors. Mitigation measures are therefore required.
C Effects from discharge of water from dewatering operations
C1 Effects on receiving drain water quality
12.5.28 Water quality in the Pyford Brook is shown to be generally good in the reach from Curborough to Alrewas. Groundwater quality is also generally good. Dewatering water will be routed through a series of settlement ponds prior to discharge to the Pyford Brook. This will facilitate settlement of entrained suspended solids prior to discharge to the Pyford Brook. Considering that the Pyford Brook is in hydraulic continuity with the groundwater, the addition of groundwater pumped from the void is expected to have a negligible effect on the water quality. Therefore, the magnitude of impact is considered to be negligible and
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the level of effect is deemed to be neutral. All discharge off-site will be controlled by the conditions of a discharge permit (to be obtained).
C2 Effects on receiving drain water flows
12.5.29 There will be no increase in runoff from the Application Site as is demonstrated by the drainage strategy (Appendix 5.7). All discharge off-site will be controlled by the conditions of a discharge permit (to be obtained).
C3 Diversion of baseflow from one catchment to another
There will be some diversion of baseflow from Drain A to the Pyford Brook as a result of the Proposal. However, Drain A joins the Pyford Brook 300 m downstream of the Application Site and is a low sensitivity receptor. This baseflow diversion is considered to produce a substantial magnitude of impact on Drain A (a low sensitivity receptor), producing a moderate/minor level of effect. this diversion is therefore not considered significant.
D Effects from restoration
D1 Long term impact on groundwater levels
12.5.30 The long-term impact on groundwater levels is considered to be negligible as, given the high permeability of the strata, the excavation areas are expected to rapidly recover upon cessation of dewatering. The resultant waterbodies within the voids will not have an outfall or inflow and the final level will be controlled by the recovering groundwater level. The waterbodies will cause localised drawdown at the up gradient western part of the lakes and will cause a similar slight increase in levels at the down-gradient eastern side of the waterbodies. Given that the groundwater gradient is very shallow under baseline conditions, any changes in water level would be very small and localised.
12.5.31 The receptors to this change are the water features close to the Application Site which are the Pyford Brook and Drain A. These receptors are considered to be of medium sensitivity and low sensitivity respectively and, given the small and localised change in groundwater levels, the magnitude impact is considered to be and small enough to be undetectable and therefore negligible. Therefore, the level of effect is neutral.
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D2 Additional loss of water from open water evaporation
12.5.32 Open water evaporation will be allowed to occur due to the creation of waterbodies at the Application Site. Resultant losses from the sand and gravel aquifer could affect baseflows to the neighbouring watercourses, abstractions and discharges. However, the proposed area of open water, and hence the rate of additional evapotranspiration, is small in comparison to the catchment as a whole. The magnitude of impact would therefore be negligible and the level of effect is considered to be neutral.
D3 Faster runoff and increased flood risk
12.5.33 The restored waterbodies will provide a reduction in surface water runoff by allowing additional attenuation capacity and infiltration. Runoff from within the Application Site boundary would flow into the waterbodies and then infiltrate to the groundwater instead of flowing directly to the Pyford Brook. This would act to attenuate runoff to the Pyford Brook during storm events and reduce flood risk on downstream receptors. The level of effect is therefore neutral to slightly beneficial.
12.5.34 Runoff at the Application Site will increase due to climate change. This runoff will be attenuated by the restored waterbodies and, as such, there will not be an increased flood risk downstream. Appendix 5.7 contains a drainage strategy for the restored condition to demonstrate that this is the case.
Flood risk to downstream receptors
12.5.35 Runoff from the Application Site will drain into the quarry voids and will be pumped into the settlement ponds before discharge to the Pyford Brook.
12.5.36 During normal (non-storm conditions) discharge of water to the Pyford Brook would be subject to a discharge permit and would be controlled to pose no flood risk to downstream receptors. During storm events, discharge would cease, thus ensuring there is no additional contribution to flooding at downstream receptors.
12.5.37 It is proposed to construct environmental bunds within the floodplain. Floodplain compensation for the operational phase bunds is therefore required to mitigate against the storage lost. This is discussed in the drainage strategy, which demonstrates that the
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proposed quarry voids will compensate for lost storage and actually increase the available capacity (Appendix 5.7).
12.5.38 Surrounding infrastructure and property that could be impacted by flooding are considered as very high sensitivity receptors. The A513 to the north is on slightly higher ground than the Application Site by approximately 0.5 m and so there is no risk of runoff from the Application Site causing flooding along the A513. The unnamed road to the west of the Application Site is approximately 0.2 m higher and so flood risk from the Application Site is also negligible.
12.5.39 The national grid compressor station located north of the Application Site on the opposite side of the A513 from the proposed haul road junction is topographically higher than the Application Site and flood risk to this receptor is negligible.
12.5.40 Through the proposed implementation of the drainage strategy (Appendix 5.7), flood storage would increase during the operational phase. The magnitude of impact on neighbouring receptors would be a slight benefit and the level of effect is major/moderate benefit.
Flood risk post restoration
12.5.41 Flood risk post-restoration is slightly less than pre-development as the waterbodies will act as infiltration and attenuation features as discussed in the section above. Through the proposed implementation of the drainage strategy (Appendix 5.7), flood storage would increase following restoration. The magnitude of impact on neighbouring receptors would be a slight benefit and the level of effect is major/moderate.
Flood risk to the Application Site
12.5.42 Areas of the Application Site are at risk of groundwater, fluvial and pluvial flooding. Runoff can be attenuated in the quarry void during the operational phase and the restored lakes post-restoration to ensure that runoff from the Application Site does not exceed greenfield runoff rates. To achieve this, the drainage strategy outlined in Appendix 5.7 should be adhered to.
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Summary
12.5.43 Table 12.22 presents a summary of the magnitudes of impact and levels of effect on neighbouring receptors around the Application Site due to the Proposal. Where the effect is considered significant, further mitigation measures are required and these are outlined in the following section.
Table 12.22 Summary of impacts
Type of Receptor Magnitude of Level of Receptor Significant? impact sensitivity impact effect
A Impacts on groundwater levels
SWR4 Medium Moderate Moderate Yes SWR15 Medium Moderate Moderate Yes SWR8 Medium Negligible Neutral No Neighbouring A1 SWR19 Medium Negligible Neutral No abstractions Private abstraction at Medium Negligible Neutral No Fradley Marina River Mease Very High Negligible Neutral No Effects on SSSI A2 designated WB1 Fradley sites Pool Nature Medium Negligible Neutral No Reserve WB1 Medium Negligible Neutral No Impacts on WB3 Low Slight Neutral No A3 surface water bodies WB4 Low Slight Neutral No WB11 Low Moderate Neutral No WCB Medium Moderate Moderate Yes Moderate/ Impacts on WCA Low Substantial No A4 baseflow and Minor watercourses WCJ Medium Negligible Neutral No WCH Low Negligible Neutral No
Surrounding A5 Settlement risk High Negligible Neutral No Properties
B Water quality impacts Spillage of Sand and Medium Substantial Major Yes fuels and Gravel Aquifer B1 release of Pyford Brook Medium Moderate Moderate No suspended solids etc. Drain A Low Moderate Minor No C Impacts from discharge of water from dewatering operations Effects on receiving C1 Pyford Brook Medium Negligible Neutral No watercourse water quality
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Impacts on receiving C2 Pyford Brook Medium Negligible Neutral No watercourse flows Diversion of baseflow from Pyford Brook / Moderate/ C3 Low Substantial No one catchment Drain A Minor to another Buildings & Major/ Increased Flood Risk Very High Slight benefit Yes infrastructure Moderate D Impacts from restoration Long term impact on D1 Groundwater Medium Negligible Neutral No groundwater levels Additional loss of water from Pyford Brook D2 Medium Negligible Neutral No open water catchment evaporation Faster runoff Buildings & Major/ D3 and increase Very High Slight benefit Yes infrastructure Moderate in flood risk
12.6 Additional Mitigation, Compensation, Enhancement Measures
Proposed Mitigation
12.6.1 Effects are considered likely to be significant on the following receptors:
Licenced abstraction from surface water reach SWR4;
Licenced abstraction from surface water reach SWR15;
Pyford Brook upstream of the Application Site; and
Groundwater and surface water quality due to accidental spillage etc.
12.6.2 A fuel or chemical spill is considered unlikely. However, should this occur, it would be retained within the active quarry void for a sufficient length of time to allow it to be collected using oil-absorbent materials. Contaminated material would then be disposed of in accordance with current industry best practice. Dewatering of any contaminated water from the active quarry void would cease during this time. These measures could be addressed by planning conditions applied to the planning permission.
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12.6.3 The Applicant’s policy dictates that standard practice will be followed to minimise the impact of refuelling and the storage of fuel and oil etc. on the environment in accordance with the Pollution Prevention Guidelines (PPGs).
12.6.4 Facilities for the storage of soils, fuels or chemicals will be sited on an impervious base and surrounded by impervious bund walls. For fuels or chemicals, the volume of the bunded compound will be greater than the tank capacity. Filling points, vents, gauges and sight glasses would be located within the bund walls. The bund drainage system would be sealed with no discharge to any watercourse, land, or underground strata permitted. Associated pipework would be located above ground and protected so as to prevent accidental damage. All filling points and tank overflow pipe outlets would discharge downwards into the bund. The bunded area would be regularly emptied of rainwater.
12.6.5 Drainage systems would be regularly inspected to ensure that visible oil is not present. An environmental management system would be established to ensure that all procedures follow standard best practice.
12.6.6 To mitigate impacts on the Pyford Brook and SWR4 and SWR15 abstractions, water would be discharged to the Pyford Brook upstream of the Application Site. This discharge would be undertaken periodically to maintain a minimum depth of water within the brook sufficient to support the abstractions and flows. The Applicant would use a gauge board to monitor levels within the Pyford Brook to ensure that levels are maintained. This discharge may also assist in lessening effects on waterbodies to the west of the Application Site (that are currently assessed as being non-neutral but are not significant). It is considered likely that this discharge will not be required, or will be required less frequently, during working of the eastern phases. A discharge permit would be obtained prior to the discharge being undertaken.
Flood Risk Mitigation Measures
12.6.7 There is a risk of fluvial, pluvial and groundwater flood risk at the Application Site. The EA offers a flood warning system and the Met Office also offers a flood warning service. The Applicant would sign up to these systems during the operational phase.
12.6.8 If a flood is forecast, management should inform staff to be prepared for possible flooding and to undertake the relevant procedures if these need to be enforced. However, flood forecasts are issued relatively frequently and this does not necessarily mean that flooding
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should be expected. Egress routes from areas of the Application Site within Flood Zone 3 to higher ground would be maintained throughout the operational phase.
12.6.9 All mobile and fixed plant should not, where practical, be stored in areas of Flood Zone 3. Soil stockpiles (other than the screening bunds) would be located outside of Flood Zone 3. There is sufficient compensatory storage within the voids to ensure that there will be no increase in flood risk from constructing the screening bunds within the floodplain. This is demonstrated in Appendix 5.7. In fact, flood storage would be greater during the operational phase than the existing greenfield condition. This will reduce flood risk to downstream receptors.
12.6.10 The bunds will be constructed parallel to flow to ensure that flows in the Pyford Brook are not obstructed or diverted. Pipes will be constructed through the bunds in line with the designs provided in the drainage strategy (Appendix 5.7). This is to convey flood flows to the additional floodplain compensation storage provided by the quarry voids.
12.6.11 The Application Site is to be restored to no greater than original ground levels, therefore there will be no reduction of floodplain storage. All bunding and spoil heaps at the Application Site will be levelled as part of the restoration plan. Consequently, the likelihood of fluvial flooding will be the same as the pre-existing fluvial flood risk following restoration. The waterbodies created at the Application Site will provide additional flood storage capacity and there will be no outflow. This additional floodplain storage will provide a slight reduction in flood risk to downstream receptors and is a benefit of the Proposal.
Proposed Monitoring
12.6.12 It is proposed that the following monitoring will be undertaken:
Groundwater levels in all boreholes;
Groundwater quality monitoring in all boreholes;
Monitoring of surface water levels in the Pyford Brook upstream of the Application Site; and
Water quality and flow monitoring as required by the abstraction licences and discharge permit (to be obtained).
12.6.13 Monitoring of water levels in the Pyford Brook would be used to inform the requirement for the mitigation measure mentioned above.
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12.7 Assessment Summary and Likely Significant Residual Environmental Effects
12.7.1 Only those impacts identified above as having a significant effect have been taken forward to the residual impact assessment presented in Table 12.23. Additional mitigation is not required based on this assessment. Where the magnitude of impact has been reduced this is based on the expected effect of applying the mitigation specified in Section 12.6.
12.7.2 Flood risk to downstream receptors will reduce and this has been assessed to be a slight benefit of the Proposal.
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Table 12.23 Assessment Summary of Residual Environmental Effects
Summary Residual Sensitivity Nature and Residual description of Impact Level of Additional Significance Confidence of Duration of Impact the identified Magnitude Effect Mitigation and Nature Level Receptors Effect Magnitude impact of Effect
Medium Substantial Temporary Major Negligible Neutral High Standard Deterioration of environmental water quality management procedures Medium Moderate Temporary Moderate Negligible Neutral High
Loss of flow Medium Moderate Temporary Moderate Negligible Neutral High
Discharge of water to Pyford Brook Medium Moderate Temporary Moderate Negligible Neutral High upstream of Reduced ability Application to abstract Site
Medium Moderate Temporary Moderate Negligible Neutral High
Slight Major/ Flood risk Very High Permanent None Slight Benefit Benefit High Benefit Moderate
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12.8 Cumulative Impacts
12.8.1 Cumulative impacts on the water environment could occur through positive interference of cones of depression caused by dewatering and abstraction. Operations at Tarmac Alrewas Quarry (2.7 km east of the Application Site) and Hanson Barton Quarry and proposed extension (5 km north-east) are sufficiently distant from the Application Site that there will be no overlap with the predicted 700 m radius of the proposed dewatering.
12.8.2 There could be some interference between the dewatering operation and neighbouring abstractions which lie to the south of the Pyford Brook or abstract from this watercourse. However, the radius of influence will be reduced to the south. This is because the abstracted water will be transferred to the Pyford Brook and the proposed mitigation of maintaining a level with the brook and lining the southern faces of the excavation areas will retard the spread of effect in this direction. Any interference would be minimal and the cumulative level of effect of the proposed operation on the groundwater environment is expected to be neutral.
12.8.3 The drainage strategy (Appendix 5.7) ensures that there will be no cumulative flooding impacts. The creation of waterbodies may actually produce a long-term beneficial impact.
12.9 Impact of Climate Change
12.9.1 The effect of climate change on flood risk is considered in the drainage strategy (Appendix 5.7). Climate change will not impact upon the water environment in other aspects.
12.10 Conclusion
12.10.1 In this EIA chapter, the potential hydrogeological and hydrological impacts have been reviewed, together with flood risk for the Proposal at the Application Site. Based on this study, the following conclusions have been drawn:
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The conceptual model indicates that the sand and gravel aquifer is hydraulically connected to surface watercourses and waterbodies. Groundwater flows eastwards.
Receptors are buildings and infrastructure, the River Mease SSSI, Pyford Brook, Drain A and neighbouring licenced abstractions and private water supplies.
Effects on water levels, water quality, licenced abstractions and baseflow have been assessed and these are largely expected to be insignificant. Significant effects could occur on the Pyford Brook, licenced surface water abstractions from the Pyford Brook upstream of the Application Site, and on water quality from spillages
Effects from spillages are mitigable to insignificant using standard water quality control measures. Impacts on the Pyford Brook and abstractions from it can be mitigated by discharge of dewatering water to the Pyford Brook upstream of the Application Site.
Dewatering would be undertaken under the terms of an abstraction (transfer and full) licence (to be obtained).
Discharge from the Application Site will be undertaken under a new discharge permit (to be applied for) and impacts will be insignificant.
Long term impacts on groundwater levels and stream flows have been assessed and will not be significant.
There will be no increased flood risk from the Application Site, during operation or following restoration, to neighbouring receptors and a drainage strategy has been developed to demonstrate that greenfield runoff rates are not exceeded during the operational and restoration stages.
Screening bunds will be constructed in the floodplain during the operational phase however, level by level compensation calculations indicate that there will be sufficient compensatory storage provided by the quarry voids.
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Available flood storage will increase compared to greenfield conditions for the operational and restoration stages. This will have a beneficial effect on downstream flood risk.
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REFERENCES
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Hazen, A. (1893). Some physical properties of sand and gravels. Massachussetts State Board of Health. 24th Annual Report.
HR Wallingford. (2019, March). Greenfield runoff rate estimation tool. Retrieved from http://www.uksuds.com/drainage-tools-members/greenfield-runoff-rate-tool.html
Jones, H. K., Morris, B. L., Cheney, C. S., Brewerton, L. J., Merrin, P. D., Lewis, M. A., . . . Robinson, V. K. (2000). The physical properties of minor aquifers in England and Wales. British Geological Survey Technical Report WD/00/4, 234.
NSRI. (2019). Retrieved October 2019, from LandIS Soilscapes Viewer: http://www.landis.org.uk/soilscapes/
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