1. Water Resource Management – Monitoring,
Conceptualisation, and Groundwater Flow
and Transport Modelling, Field Investigation

2. ESI is the UK’s leading independent scientific and environmental
consultancy specialising in water resource management, land quality and
ground source energy. As a technical specialist advisor to corporate and
governmental clients ESI is respected for its pragmatism, sound science
and strong commercial focus.
Water Resource Management – Monitoring,
Conceptualisation, and Groundwater Flow and
Transport Modelling, Field Investigation.
Consultancy Services for Water Resources
ESI is a specialist consultancy dealing with flow and transport modelling ESI is recognised
all aspects of groundwater science and as the leading independent provider of water
groundwater resource management and has resource services. Groundwater support is
one of the largest and most technically capable provided to a diverse group of clients who need
groundwater teams in the UK. With a detailed to understand, assess, map and plan, including:
technical understanding and experience of Utility companies, Developers, Extractive, Mining
the key issues involved in field investigation, and Tunneling companies, Local Authorities and
monitoring, conceptualisation, and groundwater the Environment Agency.
Low Flow Studies and Hydro-ecology
Traditionally, water resource assessments for
groundwater abstraction have focused on the impacts
at a relatively large or catchment scale. Ecological
concerns are often very local and site specific. Low flow
studies and hydro-ecology assessments therefore need
to combine the broad catchment scale approach with a
more detailed local understanding. ESI’s combination of
strong technical skills with a detailed experience of local
scale processes is essential to resolving these issues.
ESI has over 15 years of experience working with a range of clients, particularly in the water
industry, to develop more targeted and efficient ways of defining the impact of groundwater
abstraction on surface water ecology (hydro-ecology). With multiple and complex projects
completed ESI has a record of working alongside other specialists (e.g. in aquatic ecology and
hydrology) as part of a team to deliver clear answers to these problems.

3. Groundwater Modelling
Groundwater models can improve our In order to produce a groundwater model
understanding of how aquifer systems that can be used as a reliable management
behave and can be used to make tool, it is essential to base it on a carefully
predictions about the system’s future worked out conceptual model. This requires
behaviour. Specific questions that can be a thorough review of all the relevant
addressed using a groundwater model data. The consultancy team at ESI has
include: extensive experience and are able to use
their knowledge in this area to select the
• How might a change in abstraction be right groundwater modelling approach for
used to improve river flows or reduce the problem being faced. Groundwater
impacts on a wetland? models should never be more complex
• Is a potential river support scheme than the problem requires or available
effective? data allows.
• How might climate change influence ESI has one of the largest and most by their clients. Groundwater models have
available resources? technically capable groundwater modelling been developed to solve problems involving
teams in the UK. Over the last decade the water resource management, borehole
• Will this abstraction cause saline team has consistently delivered technically yield, tunnel dewatering, quarry dewatering,
intrusion? robust groundwater models that are climate change, saline intrusion and
• How might changes in abstraction affect used to provide practical answers to the groundwater contamination (including petrol
groundwater quality? important water resource questions faced spills and landfill issues).
Borehole Drilling and Testing and Deployable Outputs
ESI has built an experienced team of quality assured data to ensure total
groundwater scientists with a good accuracy in its reporting.
balance between pragmatic field
Water companies are required to plan
experience and in-depth quantitative
extensively for the future with detailed
skills for the analysis of field results. Water Resource Management Plans
All contractors used to support projects for the next 25 years of operation.
are carefully chosen, all must meet a A key building block of these plans is
work standard dictated by ESI and all the source reliable output assessments
are required to provide copies of their for all groundwater sources. ESI’s
own Quality and Health and Safety strengths in applied groundwater
standards and accreditations. All science and experience of borehole
contractors are supervised, whether yield assessment have been critical to
on small site investigations or on major developing an accurate assessment of
production borehole drilling and testing the water available from these sources
contracts. ESI is committed to providing for clients across the UK.
Groundwater Control and Dewatering
The development of sophisticated ESI’s senior team has extensive
tunnelling techniques on major experience of handling complex
engineering projects has led to the dewatering projects and has provided
increased demand for accurate innovative solutions to the issues faced.
predictions of rates of dewatering The consultancy team has successfully
required. In the extractive industry, developed and are operating
planning constraints on the lateral groundwater models of some of the
extensions to quarries has put largest dewatering schemes in the
increased pressure to deepen existing UK. ESI’s approach in all of its projects
sites below the water table. In both of is to work closely with clients to
these industries, the energy costs of determine the most appropriate level of
dewatering have become significant assessment required for each site. This
operational factors, whilst environmental ensures that the most cost effective
constraints are often critical to the solutions can be achieved in all cases.
feasibility of these schemes.

4. Dealing with Climate Change
The impact of climate change on recharge, as has been experienced in
groundwater resources is a complex recent years. The increase in variability
issue and does not lend itself to an will make it more likely that an extended
easy solution. Most global climate sequence of dry winters could occur
models suggest that on average with potentially significant implications
there will be wetter winters and drier for water resource management. The
summers in the UK. This should imply reliability of these model predictions is
that on average there will be more still a topic for debate, in the meantime
winter recharge to the aquifer providing it is clear that increased uncertainty
increased groundwater availability requires increased resilience of water
than at present. However, increased supply systems.
variability is also a significant feature of
current climate change predictions and ESI’s strengths in quantitative
not all winters will have higher rainfall hydrogeology (including a proven track
than average. Furthermore, an increase record in calculating recharge rates
in the number of intense summer from meteorological data) are well
storms may provide significant summer suited to assessment of the risks to
water resources from climate change.
Groundwater Flood Risk Assessment and Mapping
Groundwater floods occur after long susceptible to groundwater flooding.
periods of high rainfall, when the water In addition, civil engineering work can
table rises above the ground surface. often have very localised effects on
Insurance companies estimate that shallow groundwater levels resulting in
groundwater flooding claims amount to damage to adjacent properties. In all
between £50 million and £100 million cases, understanding the causes of
per year. Each event costs about three groundwater flooding and development
times as much as fluvial or tidal flooding of robust mitigation measures requires
because a groundwater flood can last a thorough quantitative understanding
for weeks or months. 1.6 million homes of the local groundwater conditions,
in the UK that are outside existing something that ESI’s experienced staff
fluvial and tidal flood risk areas may be are well placed to provide.
Case Studies
Investigation of the London Aquifer
The aquifer beneath London is subject influence Chalk stratigraphy on aquifer
to a considerable number of stresses properties. The robust and quantified
including rising groundwater levels, conceptual model has formed the basis
abstraction sustainability, artificial for the construction of a numerical
recharge, saline intrusion, groundwater MODFLOW model. The conceptual
flooding, and the growth of ground and numerical models will aid the
source energy. ESI has recently Environment Agency manage water
undertaken two key projects for resources.
the Environment Agency to aid the
management of these pressures in a ESI has developed a coupled
sustainable and cost effective manner. groundwater flow-heat transport
FEFLOW model of central London,
Following consolidation and analysis of building on recent work undertaken
the available data and a comprehensive on the ‘Cooling the Tube’ project for
literature review, ESI has formulated the London Underground. The aim of
a detailed conceptual understanding the model was to provide a tool to aid
of the key hydrogeological processes the Environment Agency effectively
which occur within the London manage and make regulatory decisions
Basin aquifer. Using the most-up- regarding open-loop ground source
to-date interpretation of the geology energy schemes. A series of models
beneath London, ESI furthered current were developed to simulate heat
understanding of geological controls on transport under a range of operational
groundwater flow, most notably faulting scenarios, including ‘worst case’ and a
and structure within the basin and the range of realistic operating conditions.

5. Low Flow Investigation Sites
Over the last ten years ESI has worked dropped from the programme.
closely with Severn Trent Water on
key low flow sites in the Midlands, ESI drew up a scope of further
spanning the AMP3, AMP4 and investigations for each site and
AMP5 programmes in 40 catchments was then appointed with partners
and reviewing over 60 PWS to carry out the works. In AMP4
abstraction boreholes. this involved detailed site surveys,
15 new observation boreholes
The sites were initially flagged up by and an extensive programme of
the Environment Agency and included groundwater level and spot flow
several SSSIs and a Habitats Directive gauging (80 sites) over a 3-5 year
site. ESI worked closely with STWL, period at each site. The data
the regulators and other specialists collected was regularly reviewed and
to determine whether these concerns annual reports presented. At the
were justified. At several of the sites it end of the monitoring period, ESI
was quickly apparent that either there prepared impact assessment reports
was a significant low flow problem to summarise the improvement
and the site could progress to options of understanding of the problem
appraisal or there was no significant and to make an assessment of the
PWS impact and the sites could be significance of any impacts.
Cornelly Group of Quarries
The planning permissions for the boreholes and borehole and surface
Cornelly Group of Quarries were geophysics), monitoring (level, flow
subject to review under the provisions and quality), tracer tests, data review
of the Environment Act 1995 and analysis, development of a
(ROMP). The National Assembly for conceptual model and preparation of
Wales (NAW) had concerns about the Environmental Statement.
the potential impacts of further
working of the quarries; the regulators Negotiation and technical discussion
had particular concerns about the with the regulators was a central
potential for dewatering Special part of the assessment due to the
Areas of Conservation under the complexity of the local hydrogeology
Habitats Directive. and the potential degree of uncertainty
in any predictions that could be made.
The NAW requested Environmental The work was carried out in a phased
Statements to assist in the manner to allow results from the early
determination of the ROMP stages to be circulated and the scope
submissions. Tarmac appointed for later phases to be adjusted in
ESI to carry out a hydrogeological the light of these findings. Work has
investigation and impact assessment, progressed through the EIA stage and
the work involved field investigations is now focussed around future water
(construction of 20 new monitoring management at the site.
Croydon Cable Tunnel
National Grid’s plan to construct a mitigating the potential risks to water
10 km tunnel to house its new 400kV supplies and supporting discussions
line through South Croydon was a with the Environment Agency and
great way of avoiding years of traffic Thames Water.
disruption. The tunnel needed to be
The risks to the sources were
built carefully through the chalk aquifer,
minimised by changes to the design of
an important source of public water the tunnel and an ongoing groundwater
supply, passing within a few hundred level and quality monitoring programme
metres of several of Thames Water’s throughout the course of the project.
critical supply boreholes, without Detailed contingency measures were
affecting water supplies. The contract designed that would be actioned if
for the detailed design and construction certain triggers were breached. The
of the tunnel was awarded to Morgan tunnel was completed on time and
Est. ESI were a technical partner to budget with no significant adverse
involved in finding pragmatic ways of impacts on the environment.

6. Expert Witness Support
ESI has a team of senior consultants with experience of delivering Expert Witness
support in groundwater, groundwater flooding, land contamination, ground source
energy and in relevant sub-specialisms. The Expert Witness team is supported by
industry leading technical consultants.
EurGeol Mark Fermor Expert Witness
BSc MSc DUC MBA CGeol FGS
Managing Director ESI Ltd
Mark Fermor is a hydrogeologist with particular expertise in quantitative methods for resource management, contamination
assessment and groundwater modelling. He has practical experience of investigating and remediating a wide range of
contamination hazards in soil and groundwater and in undertaking hydrogeological risk assessments using both qualitative
and quantitative methods.
Mike Streetly Expert Witness
BSc MSc CGeol FGS
Water Resources Director ESI Ltd
Mike Streetly is a very experienced hydrogeologist and project director/manager who is well known throughout the industry for his
skills and experience in water resource assessment. He has strong numerical skills which have been applied to solving a wide variety
of hydrogeological problems. He also has extensive practical experience, particularly in the design, installation and operation of
hydrometric networks and pumping tests.
Dr Steve Buss Expert Witness
MA MSc PhD FGS CGeol
Principal Hydrogeologist, ESI Ltd
Dr Steve Buss is a Chartered Geologist with extensive experience of understanding and modelling groundwater flow and
contaminant transport. He has led projects that have examined groundwater flow and contaminant transport in all the principal UK
aquifers; from the site scale to the scale of regional aquifers. These have included: assessments of groundwater resource availability,
the impact of groundwater abstraction on stream flows, the impacts of changes in groundwater flow on groundwater chemistry, and
risk assessments for groundwater flooding.
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