ESI, now part of Stantec, supported the preparation of the hydrogeological component of the Environmental Impact Statement for a proposed reservoir. Groundwater and solute transport modelling were used to predict groundwater chemistry in the aquifer beneath the proposed reservoir site resulting from a complex hydrogeological history, with old, brackish water being flushed by fresh recharge wasters.
Thames Water wished to re-evaluate the requirement for a major water resource development in the Upper Thames area including the case identified previously for a reservoir south west of Abingdon. A project team was appointed by Thames Water to undertake this work.
ESI supported Thames Water and Cascade Consulting in the preparation of the hydrogeological component of the Environmental Impact Statement (EIS) for the proposed scheme. ESI also worked alongside Jacobs UK Ltd which was appointed by Thames Water to lead the engineering input to the project. An integrated approach to the groundwater related aspects of the engineering and environmental components of the project is critical to a successful outcome for the project.
ESI had previously been working with Thames Water for a number of years to carry out baseline work at the site. In parallel with the ongoing fieldwork programme, ESI developed the hydrogeological conceptual model that was a critical component of the EIS, and a fundamental step towards determining whether the proposed scheme will have impacts on the groundwater system and wider surface water environment.
One key technical challenge to understanding the impact of a future reservoir was to be able to accurately predict current conditions. The distribution of groundwater chemistry in the aquifer beneath the proposed reservoir site is the product of a complex hydrogeological history, with old, brackish water being flushed by fresh recharge waters. Groundwater and solute transport modelling were used to successfully predict this distribution at the site.
This not only provided quantitative support for the current conceptual model but also lead to the development of a tool to predict the likely effects of the proposed development. The hydrogeological reports were reviewed by the Environmental Agency and all significant issues were addressed to its satisfaction. The need for the reservoir is currently under review as part of the public inquiry into Thames Water’s Resources Management Plan.
ESI’s innovative and proactive approach to groundwater investigation and characterisation has yielded key contributions to the EIS and improved the understanding of the groundwater system greatly.
Please contact us for more information on ‘Upper Thames Major Resource Development’.