Modelling can be a useful support to decision-making, permitting our understanding of groundwater systems to be tested and refined, and allowing the results of the proposed management strategies to be predicted. We have a long and successful track record, both in the application of industry standard modelling approaches and in the development of modelling tools and practice.

Groundwater Resource Modelling

The Environment Agency uses groundwater models extensively as tools to facilitate their management of groundwater resources. For example, over the last 15 years it has run a programme to develop a series of regional scale groundwater models covering the major aquifers of the UK, and these are used routinely for hydrogeological impact assessment in connection with a wide range of issues. We have worked extensively in this programme, providing project management and technical direction to individual projects, contributing to the development of a national, user friendly platform for model use, and involved in initiating an active forum for knowledge transfer amongst groundwater modellers.

We can provide:

• Conceptual modelling; types and availability of data, techniques for integration, analysis and interpretation of data, identification of key processes, recharge calculations (FAO method, EA and 4R codes etc...), water balance calculations
• Development of models, translation of conceptual models into numerical models. Critical assessment of advantages and limitations of various boundary conditions, presentation of modelling results, techniques for refinement and validation of models. Treatment of uncertainty is a key component of our modelling process; estimation or analytical/numerical propagation, significance of results in the context of decision-making.
• Predictive modelling: assessment of the capabilities and limitations of models (e.g. calibration envelopes), scaling issues relating to application of large-scale model results to small-scale sites (e.g. wetlands), techniques for down-scaling predictive results, predictive error versus receptor sensitivity, drought and climate change predictive modelling
• We have experience in developing modelling software, with a central role in the development of the Agency's MODFLOW VKD package for modelling variable permeability with depth in the Chalk aquifer, and involvement with the development of the Environment Agency’s National Groundwater Modelling System (NGMS)

Assessing the risks from groundwater contamination

We have extensive experience of undertaking and reviewing 'controlled waters risk assessments', including those for re-development of brownfield sites under the planning regime, Part 2A (contaminated land) of the Environment Protection Act (1990), the Groundwater Regulations (1998) and pollution under the Water Resources Act (1991). This is always underpinned by an appropriate level of conceptual modelling, identification and quantification of critical features and processes within a source-pathway-receptor framework.

Our services include both deriving and reviewing remedial targets for planning applications, voluntary remediation or Part 2A using the EA's Remedial Targets Methodology, RBCA, bespoke probabilistic modelling, and modelling the behaviour of contamination using ConSim and numerical modelling solutions (including MT3D). We provide peer review, regulatory advice and guidance on assessment of the risks to controlled waters from soil and groundwater contamination.

Hydrogeological risk assessment for landfill

We have undertaken numerous Hydrogeological Risk Assessments (HRA) of the potential risk posed to groundwater in compliance with the Landfill Regulations and PPC (now EPR), and have undertaken extensive reviews of third party HRAs when working for the Environment Agency. Risk assessments are undertaken using LandSim or bespoke probabilistic models. Our services include review and management of site investigation data, review of groundwater, surface water and leachate monitoring regimes, detailed hydrogeological conceptualisation of a site, review and derivation of control and trigger levels, and support with regulatory matters.