Tarmac Limited

Avon CommonInstalling recharge pipeline

County: Dorset.
Mineral: River terrace sand and gravel.
Project: Planning application for new quarrying and inert landfill within a greenfield Site.
Planned Workings: Full depth dewatering of mineral during operations.
Mitigation: Groundwater Quality and Level Monitoring with agreed trigger values and contingency mitigation. Peripheral groundwater recharge during mineral extraction.
Approximate Consented Reserve: 2.5mt.
Project Areas: EIA, HRA, PPC, LDC, ALA, RHM, S106.

Setting out recharge trials at Avon CommonAvon Common is situated within an ecologically important and hydrologically sensitive area, being surrounded by Nationally and Internationally designated Sites of Special Scientific Interest (SSSI’s) and Special Areas of Conservation (SAC’s).

Extensive data collection, routine monitoring over several years, computer-based modelling works and discussions with the Environment Agency and Natural England were undertaken by BCL to assist Tarmac in securing planning permission for some 2.5mt of sand and gravel at Avon Common, Dorset.

The potential for increased risk of bird strike related to possible expansion of open water adjacent the flood plain of the River Avon will be avoided by pumped dewatering of the full depth of Extending recharge trials at Avon Commonmineral and restoration to pre-quarrying ground levels via inert landfill. The potential for dewatering to impact upon surrounding sites of ecological importance will be minimised by a groundwater recharge and support system; that has been extensively field-tested by BCL in advance of quarrying operation.

EIA: Environmental Impact Assessment.
HRA: Hydrogeological Risk Assessment (in accordance with EA LFTGN01)
PPC: Pollution Prevention & Control Permitting.
LDC: Land Drainage Consent Application.
ALA: Abstraction Licence Application.
RHM: Routine Hydrometric Monitoring.
S106: Scheme developed for Section 106 (Town & Country Planning Act) Agreement.

Plumley WoodPlumley Wood

County: Hampshire.
Mineral: River terrace sands and gravels & Tertiary sands.
Project: Planning Application for quarrying, on-site processing, restoration to agriculture and wildlife after-uses within a greenfield site.
Planned Workings: Full depth dewatering of mineral during operations, extensive passive water-management scheme as part of site restoration.
Mitigation: Hydrological and hydrogeological monitoring allied to contingencies for gravity-fed groundwater recharge.
Approximate Consented Reserve: 6.3mt.
Project Areas: EIA, FDC, ALA, DCA, RHM, EP.

Workings at Plumley Wood involve winning of terrace sands and gravels together with underlying Tertiary sands within an extraction area totalling some 101.5ha. The site is situated adjacent a number of ecologically important and hydrologically sensitive areas, including a number of Sites of Special Scientific Interest.

BCL planned and implemented a programme of hydrological monitoring, the data from which allowed the water environment of the site to be conceptually modelled. This model provided a robust platform for risk assessment, which concluded that the potential impacts associated with this large-scale quarrying proposal were insignificant.

BCL formulated a scheme of water supply and management which meant that processing of mineral could take place on site. This will deliver significant additional margins for the quarrying operation as it eliminates the need for transportation of mineral for off-site processing. Collection and interpretation of stream flow data facilitated a successful abstraction licence application within a catchment deemed by EA CAMS to be under considerable water resources pressure.

EIA: Environmental Impact Assessment.
FDC: Flood Defence Consent Application.
ALA: Abstraction Licence Application.
DCA: Discharge Consent Application.
RHM: Routine Hydrometric Monitoring.
EP: Environmental Permitting.

Greenham CommonFace Sampling at Greenham Common

County: Berkshire.
Mineral: Plateau sands and gravels.
Project: Planning Application for quarrying and off-site processing with restoration to mixed wet and dry heathland within a site blighted by cold-war military infrastructure.
Planned Workings: Mineral extraction above groundwater with simultaneous testing for hydrocarbon contamination. Contaminated materials to remain on-site for treatment. Clean mineral to be transported to existing processing plant upon valley floor via SSSI. Passive water management following restoration.
Mitigation: Continuous sampling for hydrocarbons. Hydrogeological compliance monitoring at both the extraction and receptor sites.
Approximate Consented Reserve: 1.3mt.
Project Areas: EIA.

During the late 1990’s, Tarmac formulated a plan that would lead to the remediation of the eastern end of the 3.6km runway serving the former Greenham Common airbase. The military history of the site had left a legacy of near-surface groundwater contamination, deriving mostly from long-term leakages of aviation fuel. Tarmac’s proposal was to extract clean mineral from the airfield for transportation and processing at their nearby Lower Farm Quarry. Contaminated materials were to remain on-site at the Common, to be remediated by Tarmac / the Greenham Common Trust.

BCL devised a methodology of materials testing, that operated along-side the extraction programme, to ensure that all materials transported to Lower Farm Quarry were free of contamination. This involved the establishment of a specially constructed on-site laboratory; a particularly important facet of the project, given the location of Lower Farm Quarry, adjacent to the River Kennet SSSI corridor. The scheme of materials testing was allied to a programme of compliance testing to determine residual impacts upon ground water quality at the two sites. Following extensive discussions with the Environment Agency, agreement was reached with all parties and planning permission granted in 2000.

The compliance monitoring programme, devised and implemented by BCL, has demonstrated that this potentially difficult project was undertaken successfully, without impacting upon either on-site or off-site groundwater quality.

EIA: Environmental Impact Assessment.

Sevenoaks QuarrySevenoaks Quarry

County: Kent.
Mineral: Sand (Folkestone Beds).
Project: Planning Application for extension of existing site.
Planned Workings: Dry dig of mineral above the water table and suction dredger below watertable.
Mitigation: Groundwater Level and Quality Monitoring with agreed trigger values and contingency mitigation.
Approximate Consented Reserve: 6.6mt.
Project Areas: EIA, FRA, RHM, ALA.

The geological succession at Sevenoaks Quarry comprises Gault Clay overlying the Folkestone Beds, which in turn are separated from the underlying Hythe Beds by the Sandgate Beds. The Sandgate Beds are a thin clay horizon of between 1 and 3m thickness. Both the Folkestone and Hythe Beds are aquifers, the Hythe being used for Public Water Supply abstraction in the near locality.

Extensive data collection and computer based assessment, alongside discussions with the Environment Agency and Natural England were undertaken by BCL to assist Tarmac in securing planning permission for some 6.6mt of sand within a lateral extension to the existing quarry.

A program of monitoring and contingency mitigation was developed by BCL to ensure the integrity of the Sandgate Beds is maintained whilst the Folkestone Beds are extracted. The long term integrity of the beds will be maintained through placement of gault clay overburden within the dig area. Flood risk will be reduced to pre-development levels through the control of runoff to the Greenfield Runoff Rate and construction of a flood attenuation lagoon designed (in accordance with prevailing guidance) to accommodate the 1 in 100 year critical storm event.

EIA: Environmental Impact Assessment.
FRA: Flood Risk Assessment.
RHM: Routine Hydrometric Monitoring.
ALA: Abstraction Licence Application.

Bankfield QuarryBankfield & Lanehead Quarries

County: Lancashire.
Mineral: Carboniferous Limestone.
Project: Planning Application for deepening of an existing quarry.
Planned Workings: Full depth dewatering of mineral during operations.
Mitigation: Extensive Groundwater and Surface Water Monitoring Programme with agreed trigger scheme and contingency mitigation.
Approximate Consented Reserve: circa 30mt.
Project Areas: EIA, RHM.

Bankfield is a large and long-established quarry working the Carboniferous (Chatburn) Limestone, from within a void shared with Hanson Limited, situated near Clitheroe, Lancashire.

A Planning Application was submitted during 1997 to extend the basal workings of the Quarry from 0m above Ordnance Datum (maOD) to 50 metres below Ordnance Datum (mbOD); an elevation some 125m below the pre-quarrying level of groundwater at the site.

Extensive data collection, routine monitoring over several years, computer-based modelling works and discussions with the Environment Agency (EA) were undertaken by the staff of BCL to assist Tarmac in securing planning permission that would deliver an additional 3-decades of limestone extraction at the quarry.

Outstanding EA concerns regarding the potential for unforseen impact upon the flow rates (and hence; ecology) of several water-courses in the area of the Quarry were met by the development of a Water Environment Protection Scheme (WEPS). The WEPS provided a specification for Baseline Monitoring, setting of Impact Assessment Criteria, Impact Monitoring and Reporting to operate contemporaneously with extraction from 0maOD to 50mBOD.

Assessment of monitoring data collected under the auspices of the WEPS has, to date, demonstrated that the findings of the original EIA were robust; no discernable impact upon watercourses nominated as sensitive and important having been detected.

EIA: Environmental Impact Assessment.
RHM: Routine Hydrometric Monitoring.

Eysey Manor QuarryEysey Manor Quarry

County: Wiltshire.
Mineral: Sand and gravel.
Project: Planning application for a new quarry with restoration using imported inert infill.
Planned Workings: Full depth dewatering of mineral during operations.
Mitigation: Extensive groundwater and surface water monitoring programme with agreed trigger scheme, reporting and contingency mitigation.
Approximate Consented Reserve: circa 2.7mt.
Project Areas: EIA, DCA, FDC, RHM, S106.

Hydrological and hydrogeological baseline and impact assessments were conducted in respect of a planning application seeking approval for sand and gravel quarrying and subsequent restoration over some 150 hectares of agricultural land at Eysey Manor Farm, near Cricklade. The assessments involved correlation and examination of hydrogeological and hydrological data supplied by the Environment Agency and Natural England, together with data collected from the site itself.

Assessment concluded that where potential for impact exists, the degree of risk was small. Several specific measures were incorporated into the design of the project to fully mitigate against the potential for impacts upon adjacent designated sites, which included a number of SSSI’s and a cSAC.

Due to the international importance of the nearby cSAC as a site of nature conservation a scheme of monitoring and mitigation was developed by BCL and agreed with the Environment Agency. The adopted monitoring, data analysis and trigger scheme was judged by all stakeholders to be an effective method of giving prior warning of impact and thus acting as a trigger for further mitigation. As hydrometric monitoring was required outwith the permitted area, the scheme was incorporated into a Section 106 agreement which ensured its enforceability, giving further confidence to all relevant stakeholders.

Operation of the scheme since quarrying began at the site in the early 2000’s has demonstrated that quarrying has proceeded as predicted by the original impact assessment and that effects upon designated sites has not occurred.

EIA: Environmental Impact Assessment.
DCA: Discharge Consent Application.
FDC: Flood Defense Consent.
RHM: Routine Hydrometric Monitoring.
S106: Scheme developed for Section 106 (Town & Country Planning Act) Agreement.

Halecombe QuarryHalecombe Quarry

County: Somerset.
Mineral: Carboniferous limestone.
Project: Planning application for deepening of existing quarry.
Planned Workings: Full depth dewatering of mineral during operations.
Mitigation: Extensive groundwater and surface Water monitoring programme with agreed trigger scheme, reporting and contingency mitigation.
Approximate Consented Reserve: circa 30mt.
Project Areas: EIA, RHM, S106.

EIA: Environmental Impact Assessment.
RHM: Routine Hydrometric Monitoring.
S106: Scheme developed for Section 106 (Town & Country Planning Act) Agreement.

Rock Common QuarryRock Common Quarry

County: West Sussex.
Mineral: Sand (Folkestone Beds).
Project: ROMMP Submission.
Planned Workings: Full depth dewatering of mineral during operations.
Mitigation: Groundwater and surface Water monitoring programme.
Approximate Consented Reserve: circa 0.7mt.
Project Areas: EIA.

The potential for continued working of sand reserves and subsequent restoration at Rock Common Quarry to impact upon the water environment were assessed by BCL on behalf of Tarmac Limited as part of the ROMPP process.

Measures for the protection of water quality from accidental spillages of potentially contaminating fluids were developed and agreed with the Environment Agency. Geotechnical assessment provided restoration slope parameters for the stability of adjoining land. The issue of quarry floor heave was been addressed and a maximum extraction depth specified as a result.

ROMPP: Review of Old Mineral Planning Permission (Environment Act 1995, Section 96).
EIA: Environmental Impact Assessment.

Broom QuarryGroundwater level Contours at Broom Quarry

County: Bedfordshire.
Mineral: River terrace and fluvio-glacial sand and gravel.
Project: Planning application for a satellite extension to an existing quarry.
Planned Workings: Full depth dewatering of mineral during operations.
Mitigation: Extensive groundwater and surface water monitoring programme with agreed reporting protocols.
Approximate Consented Reserve: circa 7mt.
Project Areas: EIA, FRA, PPC, LDC, ALA, DCA, S106.

BCL conducted an assessment of the hydrogeological and hydrological implications of a proposed southern satellite extension to existing operations at Broom Quarry near Biggleswade, Bedfordshire. The proposed development involved sub-watertable working; dry working conditions to be achieved by conventional sump-dewatering. Restoration sought to bring much of the land to be quarried back into agricultural use, with the addition of a conservation lake and two agricultural irrigation lakes.

The principal hydrogeologically related impact of the proposed development involved the secondary effects of groundwater lowering associated with the requirement to dewater the mineral. Calculation, based upon field and laboratory derived data, indicated a representative radius of influence of dewatering upon the watertable of some 70m. Two licensed groundwater abstractions existed with this predicted radius of influence. A programme of monitoring allied to contingency mitigation was developed and agreed with the Environment Agency for the protection of the licensed sources. Contingency mitigation would be by means of augmentation supply volumes from the quarry dewatering system. To date, monitoring has not indicated any deleterious effects of quarry workings upon the water environment.

EIA: Environmental Impact Assessment.
FRA: Flood Risk Assessment.
PPC: Pollution Prevention & Control P{ermit Application.
LDC: Land Drainage Consent Application.
ALA: Abstraction Licence Application.
DCA: Discharge Consent Application.
S106: Scheme developed for Section 106 (Town & Country Planning Act) Agreement.

Cardew Mires QuarryCross Sections through the River WampoolCross Sections through the River Wampool

County: Cumbria.
Mineral: River terrace and fluvio-glacial sand and gravel.
Project: Section 73 Planning application for a time extension to an existing quarry, including provision of a water management scheme in satisfaction of Planning Conditions.
Planned Workings: Partial dewatering of mineral during operations.
Mitigation: Groundwater and surface water monitoring programme.
Approximate Consented Reserve: .
Project Areas: EIA, FRA.

EIA: Environmental Impact Assessment.
FRA: Flood Risk Assessment.

Swinden QuarryHydrometric Data

County: North Yorkshire.
Mineral: Carboniferous Limestone.
Project: Routine Hydrometric Monitoring in accordance with Planning Conditions using a combination of automated data-loggers and manual measurements of stream stage and flow.
Planned Workings: Dewatering of mineral during operations.
Mitigation: Groundwater and surface water monitoring programme.
Approximate Consented Reserve:.
Project Areas: RHM.

RHM: Routine Hydrometric Monitoring.

Ballidon QuarryFeH Defined Catchment Areas

County: Derbyshire.
Mineral: Carboniferous Limestone.
Project: Hydrogeological & Hydrological Impact Assessment & Flood Risk Assessment. Routine Hydrometric Monitoring in accordance with Planning Conditions.
Planned Workings: Dewatering of mineral during operations.
Mitigation: Groundwater monitoring programme.
Approximate Consented Reserve: .
Project Areas: EIA, FRA, RHM.

EIA: Environmental Impact Assessment.
FRA: Flood Risk Assessment.
RHM: Routine Hydrometric Monitoring.

Regional Topography

Soughs

Broom South QuarryCorrelated Borehole Logs

County: Bedfordshire.
Mineral: Fluvioglacial Sand and Gravel.
Project: Assessment of the Volumes of underlying Glacial Clay available for Restoration Purposes in view of the Potential for Basal Heave.
Planned Workings: Over-digging of basal Glacial Clays to provide infill materials for Agricultural Restoration.
Mitigation: Specification of Safe Working Elevation based upon Extensive Site Investigation & Data Interpretation.
Approximate Consented Reserve: .
Project Areas: Joint Hydrogeological & Geotechnical Engineering Assessment.

EIA: Environmental Impact Assessment.
FRA: Flood Risk Assessment.
RHM: Routine Hydrometric Monitoring.

Hydrogeological Cross Sections

Safe Thickness of Extraction for Glacial Clay