Hydrogeological Impact Appraisal HIA
A hydrogeological impact appraisal (HIA) is a methodology designed to fit into the Environment Agency’s abstraction licensing process, including the changes brought about by the Water Act 2003. It also fits within the Environment Agency's overall approach to environmental risk assessment and can be matched to the risk of environmental impact associated with dewatering.
The HIA should include a conceptual understanding of the groundwater system and a survey to identify water-related features that could be affected by the dewatering e.g. water supply boreholes, rivers and protected sites. The assessment is backed up by calculations of the dewatering rates and the predicted impact (groundwater level drawdown) on nearby water features. A tiered approach is taken, with the level of detail, time and cost depending on the sensitivity of the site (presence or absence of rivers, protected sites etc.) and the scale of dewatering.
For sites where high dewatering rates are needed and/or in sensitive areas, the HIA may require extensive ground investigation, water features survey(s), pumping test(s) and stream/spring monitoring. This is likely to take several months. Once the HIA is completed and submitted, the regulator has up to four months to assess the application.
Additional guidance on HIAs is available through the Environment Agency.
[edit] Related articles on Designing Buildings
- Dewatering construction sites.
- Environment Agency.
- Environmental impact assessment EIA.
- Groundwater.
- Groundwater control.
- Hydrogeology.
- Raising awareness of dewatering regulation.
- Water abstraction licence.
- Water impoundment licence.
[edit] External resources
Featured articles and news
Boiler Upgrade Scheme and certifications consultation
Summary of government consultation which closes 11 June 2025.
Deputy editor of AT, Tim Fraser, discusses the newly formed society with its current chair, Chris Halligan MCIAT.
Barratt Lo-E passivhaus standard homes planned enmasse
With an initial 728 Lo-E homes across two sites and many more planned for the future.
Government urged to uphold Warm Homes commitment
ECA and industry bodies write to Government concerning its 13.2 billion Warm Homes manifesto commitment.
Places of Worship in Britain and Ireland, 1929-1990. Book review.
The emancipation of women in art.
CIOB Construction Manager of the Year 2025
Just one of the winners at the CIOB Awards 2025.
Call for independent National Grenfell oversight mechanism
MHCLG share findings of Building Safety Inquiry in letter to Secretary of State and Minister for Building Safety.
The Architectural Technology Awards
AT Awards now open for this the sixth decade of CIAT.
50th Golden anniversary ECA Edmundson awards
Deadline for submissions Friday 30 May 2025.
The benefits of precast, off-site foundation systems
Top ten benefits of this notable innovation.
Encouraging individuals to take action saving water at home, work, and in their communities.
Takes a community to support mental health and wellbeing
The why of becoming a Mental Health Instructor explained.
Mental health awareness week 13-18 May
The theme is communities, they can provide a sense of belonging, safety, support in hard times, and a sense purpose.
Mental health support on the rise but workers still struggling
CIOB Understanding Mental Health in the Built Environment 2025 shows.
Design and construction material libraries
Material, sample, product or detail libraries a key component of any architectural design practice.
Construction Products Reform Green Paper and Consultation
Still time to respond as consultation closes on 21 May 2025.
Resilient façade systems for smog reduction in Shanghai
A technical approach using computer simulation and analysis of solar radiation, wind patterns, and ventilation.