Case Studies

Here are some examples of projects recently worked on by H Fraser Consulting.

Green is not always Good

We think of Green as environmentally friendly, but this is not always the case. At a site in Exeter, an automotive dealer wished to develop a parcel of land that was affected by copper chrome arsenate, seen in the soil as a bright green residue. This compound can pollute groundwater, and as the site was located on a sand and gravel aquifer, a clean up operation was needed to discharge planning conditions.

Site remediation

When H Fraser Consulting Ltd (HFCL) became involved with the site, we realised that the source area was poorly defined and that clean up targets were too stringent to be realistically met. We undertook site investigation to delineate the source area and confirm groundwater quality. We then did a detailed quantitative risk assessment (DQRA) to derive remedial targets, using the Environment Agency’s Remedial Targets Methodology. The risk assessment took account of the engineered cover system that was proposed for the site, and the length of time that contamination would take to move through the aquifer. We defined the remediation objectives as the reduction of leaching of soil contamination to groundwater, to meet remedial targets, and the betterment of groundwater quality.  Our Remediation Options Appraisal found that a combination of soil stabilisation with ongoing groundwater monitoring would best meet the remediation objectives, and we secured a remediation contractor to undertake the work. Having submitted a verification report for the remediation works, we are delighted that the work has been approved and the planning condition for remediation has been discharged.

The landowner is now able to use this well placed strip of land to show cars, and to develop the wider site in accordance with their planning permission.

Our work in the brownfield land sector

We understand that developers and landowners need to meet tough deadlines to keep their project on track. We provide:

  • Phase 1 and 2 investigations
  • Remediation Strategy Development and verification
  • Specialist groundwater contamination services

Location: Exeter, Southwest

Dates: 2021 – 2024

Keywords: #sandandgravel #brownfield #remediation #DQRA #RemedialTargetsMethodology #stabilisation #automotiveindustry


Closed landfill on Chalk aquifer

A closed landfill site had been used as a waste repository adjacent to a chalk pit and cement works, on the banks of a main river. The operator was concerned about potential leakage into the surface water from the unlined landfill. Routine monitoring had identified contaminants in a stream on the landfill boundary, which discharged to the river. Hydrocarbons, sulphate and ammonia were among the contaminants of concern.

Hydrogeological and hydrological characterisation included a review of historical land use as a salt pan. The investigation concluded that the site was poorly controlled and improvements were recommended to provide additional protection. Nevertheless, it could be concluded that the risks to the river were not significant.


Landfill leachate loss, northeast England

An operational non-hazardous landfill in the Northeast of England was required to update its monitoring network in response to regulatory pressure. The site is contained, with a complex lining system, and sits on a principal aquifer. Monitoring data indicated that there was a leachate escape from the landfill. Elevated concentrations of ammoniacal nitrogen and low dissolved oxygen were detected, which threatened the water quality at a downstream groundwater Public Water Supply (PWS) borehole.

Investigations were undertaken and an abstraction borehole installed to control the spread on the leachate plume in groundwater. Downstream sentinel monitoring boreholes were also installed. An historic source of leachate leakage was identified as overtopping of temporary bund during filling of a cell. The volumes of leachate lost were estimated and the likely spread of the plume was modelled. This enabled the timescales for contaminant concentrations to dissipate to be estimated.

When measured concentrations did not fall in accordance with the model results, further assessment by the operator identified ongoing leakage or leachate through the subbase of a haul road. This breach was sealed. The modelling and monitoring were pivotal in preventing the spread of the plume and protecting the PWS receptor and in the operator maintaining good working relationships with the Environment Agency and water company. Diminishing concentrations at the sentinel boreholes confirmed that the receptor was protected.


Basement Impact Assessment (London Borough of Richmond upon Thames)

Our client from Richmond upon Thames, in London, approached us because their basement extension application had been refused previously, owing to new planning guidance launching the week before their application was considered. The proposed redevelopment included a finished floor level of -2.6 m below the existing ground floor.

Richmond’s guidance states that “planning applications which feature basements will need to provide supporting information regarding the potential level of impact the proposed development will have. The applicant will need to show that the proposal will not adversely impact the site, neighbouring properties, and the wider natural environment. This includes impacts to groundwater and water transferred via throughflow.” The latest guidance can be found here.

HFCL interrogated the new guidance (which is quite different from that of other London Boroughs), seeking advice from the Local Authority where necessary. We undertook a groundwater Basement Impact Assessment (BIA) incorporating the latest planning guidance and the planners comments. The study included the following elements:

  • Desk Study;
  • Screening;
  • Scoping;
  • Site Investigation, monitoring, and interpretation of findings;
  • Impact Assessment

The HFCL Team applied a logical conceptualisation of the site based on a common sensical approach. Whilst further monitoring is often recommended in the guidance, it was realised that the information collated as part of the desk study was sufficient to demonstrate that whilst there was a groundwater flood risk, the worst case potential groundwater flooding scenario could be mitigated against.

Planning was successfully granted, and quickly too! For more information about our basement redevelopment support services, you can visit our dedicated page here.


Hydrogeological Expert Witness

Hydro expert witness

Hannah Fraser was called in as an expert witness at an inquiry into a planning application for an incinerator ash processing plant in Buckfastleigh, Devon.

The original planning application to use the quarry to dump ash from a proposed nearby incinerator had been refused and the applicant, MVV Energie appealed. Buckfastleigh Community Forum took steps to defend the decision, asking Hannah Fraser to produce a report and give evidence to the appeal hearing.

Her report highlighted deficiencies the in hydrogeological conceptual model put forward by the appellant, and argued that the proposed activity was a waste disposal activity rather than a waste recovery operation.

The refusal decision was upheld, thanks in part to her evidence.


Contaminated Land AssessmentContaminated Land Assessment, Part 2A

Hannah Fraser was instructed to provide a Part 2A assessment of a rural property affected by historical lead smelting and dyeing works.

Receptors at the site included residents, livestock (ducks, chickens and horses), a river bordering the property, and the Coal Measures Secondary Aquifer.

She did assessments on the risks to human health, controlled waters and livestock to help the local council decide whether or not to determine the site as Contaminated Land.


Qualifed Person Claire Code of PracticeQualified Person, CL:AIRE Code of Practice

The CL:AIRE Defintion of Waste: Development Industry Code of Practice requires that developers prepare a materials management plan (MMP) for their site, so that waste materials that are suitable for re-use can be re-defined as non-waste, and re-used on site without a waste management licence.

A Qualified Person must sign off the MMP, and Hannah Fraser is a registered QP who provides QP services to a range of developer clients, their consultants and agents.


Controlled Water Risk AssessmentControlled waters risk assessment

A development site in Gainsborough, Lincolnshire, was subject to planning conditions, which required that a remediation strategy be developed for the site.

Hannah Fraser undertook a controlled waters risk assessment and developed remedial targets for soils which were protective of local controlled waters receptors.

Soil concentrations did not exceed remedial targets, indicating that remediation was not required to protect controlled waters.


Training

An environmental consultancy required training in controlled waters risk assessment to allow them to offer an improved service to their developer clients.

Hannah Fraser developed and delivered a bespoke 2 day training course, and followed up the training with some on-the job support to the environmental consultancy team. Improved progress with regulatory negotiations were noted as a result.


Soils validation

Soils Validation
Soils Validation

Hannah Fraser did a soils validation sampling and reporting exercise for a local developer, just outside Shrewsbury.

Development of three properties on an old garage site was nearing completion, and validation of clean cover import was required to enable discharge of planning conditions.

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H Fraser Consulting Ltd
The Pump House
Coton Hill
Shrewsbury
SY1 2DP

01743 352797

info@hfraserconsulting.co.uk

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