Flood Investigation
When flooding incidents occur, understanding the source, pathway and mechanism of the flood is essential — whether the goal is an insurance claim, a planning application, or preventing it from happening again. Water Environment undertakes detailed flood investigations for property owners, developers, and local authorities across the UK.
Why investigate a flood?
A flood investigation answers the questions that matter after — or before — water reaches a property: where did it come from, how did it get there, and will it happen again? A clear, evidence-based answer supports a range of outcomes:
- Insurance and liability — independent evidence of the cause of flooding to support a claim or resolve a dispute over responsibility.
- Planning and development — establishing the true flood risk at a site before committing to a design or an application.
- Prevention — identifying the mechanism so that proportionate mitigation can stop the flooding recurring.
Whatever the purpose, the method is the same: establish the source, the pathway and the receptor, and back it with data rather than assumption.
Sewer and Drainage Blockage Investigations
Sewer flooding is often caused by a blockage or capacity constraint somewhere in the upstream network. We investigate the problem systematically — reviewing as-built records, undertaking site surveys, and liaising with the sewerage undertaker — to identify the source of the failure and recommend a proportionate solution, whether that is a cleansing programme, a network upgrade, or a new attenuation facility.
Surface Water Flood Investigations
Surface water flooding during intense rainfall events can affect properties that are nowhere near a river or sewer. Using LiDAR terrain analysis, hydraulic modelling and site walkover surveys, we map overland flow pathways and ponding zones, identify the contributing catchment, and model the critical return period event. Our reports identify practical mitigation options, from small-scale interception features to catchment-wide drainage strategies.
River Flood Investigations
Where riverside properties or infrastructure have been affected by fluvial flooding, a detailed post-event analysis can clarify whether the flooding was exceptional, whether it reflects a change in the river's behaviour, or whether an upstream development or change in land management is responsible. We combine gauged data, hydraulic modelling and site evidence to produce a robust and defensible investigation report.
Development Site Appraisals
If you have a development proposal for a site in or near the floodplain, we can provide a rapid appraisal of the flood risk constraints and give you a clear, honest picture of your chances of obtaining planning permission. Early-stage appraisals save time and money by identifying constraints before significant design investment is made, and they allow us to advise on how best to frame the sequential and exception test arguments for your site.
How we work
- Briefing and records review — we establish what happened and gather the evidence: as-built drainage records, flood history, gauged data, mapping and any photographs or accounts of the event.
- Site investigation — we walk the site and catchment, survey the relevant drainage and watercourses, and record the physical evidence left by the flood.
- Analysis and modelling — we analyse the data and, where it is needed, build a hydraulic model to reproduce the event and test the likely cause.
- Reporting — we set out our findings in a clear, defensible report that identifies the source, pathway and mechanism of the flooding.
- Recommendations — we recommend a proportionate way forward, whether that is mitigation works, a maintenance regime, or the evidence needed to support a claim or application.
Why Water Environment?
Our directors have a combined 40+ years of specialist experience in flood risk and hydrology, and our investigation reports are built on the same modelling and analysis we use on major flood defence and planning schemes. That means a flood investigation from us stands up to scrutiny — from insurers, planning authorities, the Environment Agency, and the courts. We work across all of England and Wales for property owners, developers and local authorities.
We are members of the Chartered Institution of Water and Environmental Management (CIWEM) and hold professional qualifications with the Institution of Civil Engineers (ICE).
Related Projects
Sainsbury's Alsager
River Daylighting · Hydraulic Modelling · Flood Investigation
Water Environment provided specialist consultancy services for this project.