Method Statement – Incident Investigation and Emergency Response
SCOPE OF SERVICES
Emergency Response
In addition to land quality assessments MWH has been successfully providing emergency
attendance and supervision in relation to pollution incidents under its Hazardous Material Spill
Assessment and Remediation Contract to Defence Estates (USF) for over 6 years. With this
experience MWH is able to provide customers with an experienced team located in 11
permanent offices and two project offices. This enables MWH to provide a rapid response to
pollution incidents as engineers can typically be on site within 4 hours of being contacted.
MWH also operates a 24 hour emergency call out system where regional engineers are on call
to attend emergency events.
Inverness
East
Kilbride
Edinburgh
Newcastle
Upon
Tyne
Belfast
Isle of
Man
Bradford
Wakefield
Warrington
Newmarket
Reading
Cardiff
High
Wycombe
Head Office
Quick response and appropriate action to a pollution event is crucial in terms of effectively
managing both financial and environmental impacts. Dispatching an experienced environmental
engineer to an incident as soon as possible can provide significant savings and benefits. MWH’s
engineers are experienced in developing and organising spill assessment investigations and
remediation works. The attending engineer is supported by a team of engineers in the office.
MWH has also worked as supervising engineers on remediation projects on behalf of clients
where the remediation works are being undertaken by another organisation contracted directly
by the customer.
MWH recently undertook as spill assessment on behalf of the USAF at the site of a fuel spill.
The following timeline highlights MWH’s approach to the incident;
April 7 (2.00pm)
MWH contacted to attend site to undertake an initial assessment of a
fuel spill.
April 7 (4.00pm)
MWH engineer attends site to undertake assessment and recommend
future actions.
April 8 (am)
MWH provides fully costed action plan.
April 8 (pm)
USAF gives go-ahead. MWH mobilises equipment.
April 11 (am)
USAF provides formal permit to excavate, MWH commences site
characterisation and assessment.
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Method Statement – Incident Investigation and Emergency Response
April 12
Site assessment complete.
April 15
Initial site assessment report and qualitative risk assessment with
recommendations provided to USAF.
The process followed above provided an appropriate response to the risks identified at the site.
Based on the results of the initial assessment future work was programmed and a full
quantitative risk assessment undertaken. This has resulted in limited remedial action being
required to remove the potential for ongoing impact to the major groundwater aquifer and
groundwater abstractions in the region.
Risk Management Assessment and Remediation Options.
Quantitative risk assessment is central to Section 57 of the Environmental Act 1995. It is used
to determine the existence of contaminated land and to assist in the development of remedial
clean up targets to mitigate the risks posed by a pollution incident.
MWH has specialist risk assessors, hydrogeologists and toxicologists experienced in a wide
range of risk assessment and groundwater modelling techniques. These models include
•
Environment Agency’s (EA) Contaminated Land Exposure Assessment Model (CLEA) to
derive site specific soil guidance values (SGVs) to complete human health risk
assessments.
•
Groundwater risk assessments are completed using the EA’s P20 methodology and more
sophisticated models including MODFLOW and MT3D.
MWH recently undertook a groundwater risk assessment to aid in the remedial design of a fuel
spill at a USAF base in the UK. Based on the findings of the model the clean up target was
derived that would protect the local groundwater abstraction wells.
In order to meet the remedial target derived using the model, MWH assessed potential clean up
options in view of cost, potential time limitations and practicability in terms limiting the impact
on the operation of the base.
The final solution was agreed after close consultation throughout the selection process to
ensure that it matched the customers needs and aspirations.
THE MWH APPROACH AND TEAM
Incident Investigation and Emergency Response Support will be lead by MWH’s Ian Hutchinson
with further support provided from one of MWH’s 11 permanent offices located across the UK,
the engineer attending the incident will be supported by a team drawn from MWH’s staff across
the UK. The team may include, water and drainage engineers, hydrogeologists, risk assessors,
geologists and environmental scientists.
All projects will be managed in accordance MWH’s Product Delivery System, which includes both
MWH’s quality assurance and environmental management procedures.
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