CASE STUDIES
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Mineral Extraction
Investigations have been undertaken at more than 150 greenfield and existing quarry sites throughout the United Kingdom and Ireland concerning a variety of issues.
Environmental Impact Assessments
EIA’s have been undertaken at more than 100 quarries in a range of rock types varying between Quaternary sand and gravel, to karstified Carboniferous limestone. The assessments are generally used to support planning applications or planning reviews. Definition of baseline conditions, installation of surface water and groundwater monitoring stations, assessment of potential impacts and mitigation measures are frequently undertaken by the company.
Geotechnical Assessment
The assessment of groundwater conditions in relation to geotechnical conditions can be undertaken by Hafren Water. Investigation of the potential for basal heave in a brick pit within the Oxford Clay and settlement due to dewatering associated with dewatering Quaternary sand and gravel river terrace deposit have recently been completed.
Surface Water Management
Surface water drainage schemes, including silt settlement lagoon design and advice upon flocculent use, are regularly undertaken by Hafren Water. Water management schemes have recently completed for brick works, hard rock quarries and a Millstone Grit quarry. The combined use of standard calculations with a very pragmatic approach to drainage, based upon extensive experience, results in schemes which are both cost effective and can be realistically implemented and easily maintained.
Waste Management
Brief summaries of some of the waste management related projects undertaken by Hafren Water since 1999 are given below. Salient project details are given.
Mineral operating company, Derbyshire
Assessment of the potential for pollution due to a tyre fire on an old landfill site set within Carboniferous Limestone. An extensive series of water quality data was analysed and discussions held with the Environment Agency together with the production of a report. It was concluded that the potential for residue from the fire to impact upon the local watercourses and springs was indiscernibly small. The Environment Agency agreed with this conclusion and no further action was required by the mineral operating company.
Landfill operator in Lebanon
Advice to local authority on an historic waste legacy
Landfill operator in Cambridgeshire
An environmental impact assessment was required prior to granting planning permission for the reworking and extension of a very large existing landfill. Field investigations were undertaken together with the preparation of a report in support of a Planning Application. The company successfully argued the case that there would be no discharge to an aquifer, which was contrary to the initial opinion of the Environment Agency, thus a detailed Regulation 15 assessment was not required. Planning permission was granted for the site in the summer of 2000.
Landfill operator in Dorset
Detailed groundwater and surface water monitoring was undertaken to address Environment Agency concerns over discharges from a landfill. Monitoring was undertaken regularly for a period of one year over which time the source of high manganese and other compounds were identified and proved to be coming from locations other than the landfill. The Environment Agency was satisfied with the results of the monitoring and subsequent assessments, no further action was taken.
Assessment of potential Regulation 15 liabilities within the northwest of England, Environment Agency
A requirement existed for all of the regions of the Environment Agency in England and Wales to undertake a comprehensive survey of all waste repositories within their remit with respect to the discharge of List 1 and List 2 substances. All of the offices of the EA, Northwest Region were visited and details collected of each site (including all landfills, lagoons, cemeteries and underground sites) and an assessment made of potential discharges to underground strata. The work was presented in the form of a Microsoft ACCESS database. The work was undertaken in co-operation with two freelance hydrogeologists and the database was prepared by Peter Dumble Associates.
Cement Works in North Wales
Advice was given on monitoring and landfill restoration schemes, including submission of reports in support of Planning Applications, liaison with the Environment Agency and contract management of a drilling programme. Proposals for the site included moving part of the landfill and surcharging the remainder. Method statements for this work were also prepared and assessment made of potential for pollution of nearby watercourses.
Cemetery in the Wirral,
Hydrogeological risk assessment undertaken with relation to an extension to an existing cemetery.
Landfill operator, Belfast
An assessment was made of the feasibility of utilising a worked-out section of a basalt quarry as a waste repository site. Site investigation work and analysis was undertaken and reported to the client. For technical and ‘political’ reasons it was concluded that it was in the clients interest not to pursue the landfilling option until a greater volume of mineral had been removed from the quarry void. The clients accepted these findings.
Landfill sites near King Lynn
Following on from previous Regulation 15 work, conceptual model reports and hydrogeological risk assessment work was undertaken for two non-hazardous landfills in a major aquifer setting. Risk assessment work entailed full probabilistic quantitative modelling. The project also required the project management of consultants undertaking the stability and landfill gas risk assessments and completion of the PPC permit application and EP OPRA forms and on-going liaison with the Environment Agency. The Permits have now been issued and engineering works have commenced.
Hazardous landfill near Huntingdon
Hydrogeological risk assessment undertaken as part of re-permitting under the PPC regime. The study included management of drilling works, undertaking small scale pumping tests and in-situ permeability tests and management of geophysical logging. The risk assessment entailed full probabilistic quantitative modelling which was undertaken to the satisfaction of the Agency, who agreed that no substantive hydrogeological issues remained with the site. To date other issues have prevented the site obtaining a PPC permit.
Proposed inert landfill and recycling facility near Doncaster
Hydrogeological risk assessment work was undertaken in support of a Planning Application for an inert landfill and recycling centre in a Magnesian Limestone quarry near Doncaster. A monitoring scheme was set up to obtain baseline conditions and provide the necessary monitoring for the forthcoming PPC Permit Application. The project entailed detailed negotiations with the Environment Agency and adjacent landholders. Planning Permission has now been granted and a PPC Application will shortly be submitted
Completed domestic landfill near St Albans
Feasibility and baseline studies have been undertaken to assess the potential impacts of re-restoring an old “dilute & disperse” domestic landfill overlying the Chalk aquifer. Issues relating to surcharging the waste and the impact of this on leachate levels within the site and on surrounding groundwater quality have been assessed. Planning Permission has now been granted for the development and a leachate monitoring scheme proposed.
Inert landfill PPC Applications
Various inert landfill hydrogeological risk assessments have been undertake in support of PPC permit applications. These have been either undertaken in isolation or whilst managing a team of consultants to provide a complete PPC application package. Site settings have included sub water-table conditions within Magnesian Limestone, Carstone, Terrace Sand and Gravels and Coal Measures strata.
GROUNDWATER DEVELOPMENT
Rural Ground Water Development
Kwara State Nigeria ( C. Leake whilst employed by Hydrotechnica)
Development of water supplies to more than 30 towns and villages throughout
Kwara State, Nigeria. Approximately 20 sites were sourced exclusively from
boreholes. The majority of the aquifers comprised basement complex rocks,
however, Cretaceous sediments and recent alluvial aquifers were also exploited.
Responsibilities included geological and geophysical surveys, borehole siting, well design, geophysical logging, design of test pumping programmes and subsequent data analysis, resource evaluation, pump selection and report writing.
Right Bank Master Plan, Sind Province, Pakistan
(C. Leake whilst employed by Mott MacDonald)
A hydrogeological investigation was undertaken on the Right Bank of the Indus River with the objective of defining the potential for groundwater development and the means of its achievement. The groundwater resource was defined in detail with an extensive drilling programme combined with surface geophysics. The hydrogeological aspects were a component of a comprehensive study which examined many aspects of development including sociological, organisational constraints to development etc. Following the resource assessment projects were identified to exploit opportunities which had been identified by the study.
EMERGENCY RELIEF
( C Leake with RedR UNHCR)
Evaluation of the feasibility of supplying a large refugee camp with water from boreholes. Geophysical assessment and geological survey followed by drilling. The project achieved limited success due to the very difficult ground conditions which made the completion of waterwells highly problematic.
Aammiq Wetland site – Lebanon
Aammiq Marsh is a wetland site of high ecological value situated in the water margins of the Bekaa Valley in Lebanon. The site has been designated an Important Bird Area in the Middle East (Birdlife International, 1994) and is included in the Directory of Wetlands in the Middle East (IUCN, 1995). It is also designated as a Ramsar site.
The ecological value of the Aammiq Marsh arises principally from the abundance of water, which renders much of the site inundated seasonally, and on occasions (2003) annually. Such wetlands are generally dependant upon the maintenance of existing conditions to ensure the continuity of their water supply. It is thus clearly of fundamental importance to gain a good understanding of the various elements of the local water environment. This in turn will allow temporal changes (both natural and anthropogenic) to be identified and will permit the early identification of significant changes to the system, which may threaten it. Such threats can be broadly sub-divided into issues of a) water quality and b) water quantity.
Many aspects of the hydrology and hydrogeology of Aammiq Marsh were considered during a visit made to the site in October 2003. It became apparent that although much valuable data had already been collected and collated, benefit would be gained from extending the range of parameters measured and the lateral expansion of the monitoring network. It was also apparent that the distribution of water within the local water environment was complex and that many factors influenced this distribution and its temporal dynamics.
Details of an expanded monitoring network were produced during and immediately after the site visit. It is considered that analysis of this data will allow more detailed characterisation of the local water system. This will have several key benefits which can be summarised as:
a) Increasing the understanding
the local water regime
b) To provide an early warning
of adverse impacts on water quality or quantity
c) To inform future management
decisions
Discussions were held with both A Rocha (the charity managing the site) and the Lebanese Ministry of the Environment in Beirut to investigate the means by which the hydrological assessment work and analysis could be progressed.