Basement Impact Assessments to Satisfy Planning and Keep Your Build on Track.
Building downwards comes with strict regulatory hurdles.
About
Get the precise, defensible basement groundwater and hydrogeological assessments required by UK local authorities to secure your planning permission for subterranean developments.
Our expertise enables us to provide you the right advice for your basement’s construction.
A Coordinated Approach to Subterranean Planning.
Local planning authorities frequently request a Basement Impact Assessment (BIA) to prove your subterranean build will not cause flooding, subsidence, or alter local water flows. A complete BIA is a multidisciplinary process.
Groundwater & Hydrogeology
We conduct the essential screening, scoping, and detailed hydrogeological assessments to evaluate how your basement interacts with the local water table.
Drainage & Flood Considerations
We assess surface water and flood risks, ensuring your drainage strategies are robust and compliant.
Ground Conditions & Structural Design
We supply the critical groundwater data that your geotechnical engineers, structural designers, and waterproofing contractors need to safely design the physical structure and assess ground movement.
Mapping the Invisible Risks Below Your Site
To satisfy planners, we must prove your basement will not act as an underground dam. Our basement groundwater assessment maps the exact conditions below your site.
What we assess:
Current Groundwater Levels
Establishing a robust baseline using site-specific monitoring evidence.
Flow Pathways & Obstructions
Calculating how the physical presence of your new basement might divert natural groundwater flows or increase flood risks for your neighbours.
Hydrogeological Conceptualisation
Building a clear, defensible model of the ground conditions for regulators.
When is groundwater modelling necessary? Not every basement requires complex numerical modelling. Often, analytical calculations are enough to satisfy planning requirements. We only recommend advanced numerical modelling if your site features highly complex hydrogeology or sits in a sensitive location.
Think you might need advanced flow simulation? Explore our Groundwater Modelling Services
Frequently Asked Questions
Does every basement need complex numerical groundwater modelling?
No. We apply a proportionate approach to every site. If simple analytical screening proves your basement has a negligible impact on groundwater flow, we will report that definitively to the planners. We only escalate to complex numerical modelling when the site’s geology or local authority explicitly demands it.
Do you handle the structural ground-movement modelling and waterproofing design?
No, those are distinct engineering disciplines. We provide the specialized basement hydrogeological assessment (calculating water levels, flows, and pressures). Your structural engineers and waterproofing specialists will then use our robust groundwater data to design the retaining walls, calculate structural ground movement, and specify the correct waterproofing systems.
What information do you need to start my assessment?
To give you an accurate scope, we need your proposed architectural basement drawings (showing depth and extent), any existing site investigation or borehole data, and any specific BIA guidance or scoping feedback you have already received from your local planning authority.