Flood Risk Assessments
Professional Flood Risk Assessments for residential, commercial and mixed-use developments, identifying potential sources of flooding and setting out practical mitigation to support planning applications.
Flood Risk Support for Planning and Development
A Flood Risk Assessment examines whether a proposed development could be affected by flooding and whether it may increase flood risk elsewhere. It considers the site, proposed use, surrounding drainage network and available mapping or flood-model information.
One Stop Consult coordinates experienced flood-risk and drainage consultants to assess potential flooding from rivers, the sea, surface-water runoff, groundwater, sewers, reservoirs and other relevant sources.
The final assessment can support a planning application by explaining the level of risk, identifying suitable mitigation and demonstrating how the proposed development can remain safe and appropriate over its lifetime.
When May a Flood Risk Assessment Be Required?
Requirements depend on the site's location, development type, Planning Authority and identified flood-risk constraints.
Flood Zones 2 and 3
Development proposed within areas identified as having a medium or high probability of river or sea flooding.
Sites Over One Hectare
Larger sites in Flood Zone 1 where surface-water management and wider flood risk must still be considered.
Surface-Water Risk Areas
Sites affected by mapped surface-water flow routes, ponding or local drainage constraints.
Change of Use
Conversions that introduce a more vulnerable use into an area where flooding may affect occupants or safe access.
Planning Conditions
Developments where an approved flood-risk or drainage strategy must be submitted or updated before works progress.
Local Flooding Concerns
Sites with known drainage problems, historic flooding, nearby watercourses or groundwater constraints.
Potential Sources of Flooding
Flood risk can arise through several mechanisms, and a robust assessment should consider all sources that may be relevant to the site.
The available evidence is reviewed to establish which risks require detailed assessment and which can reasonably be screened out.
What the Flood Risk Assessment May Include
The report is tailored to the site, development proposal and relevant planning requirements.
Site and Development Review
Description of the existing site, proposed development, ground levels, access and surrounding land uses.
Flood-Zone Appraisal
Review of available flood mapping, strategic assessments and other relevant published information.
Historical Flood Information
Consideration of known flooding incidents, local records and previous site or area studies where available.
Climate-Change Allowances
Review of how future climate change may affect flood levels, rainfall intensity and long-term site resilience.
Safe Access and Egress
Assessment of whether occupants can safely enter and leave the site during a flood event where this is relevant.
Mitigation Strategy
Clear recommendations covering finished-floor levels, layout, resilience, drainage and other appropriate measures.
Flood Mitigation Measures
The appropriate measures depend on the type and severity of risk, site constraints and proposed use.
Finished-Floor Levels
Raising internal floor levels where appropriate to reduce the likelihood of floodwater entering the building.
Flood-Resilient Design
Using suitable materials, services locations and construction details to reduce damage and speed recovery.
Site Layout
Positioning more vulnerable uses away from higher-risk parts of the site where possible.
Safe Access Routes
Identifying suitable routes, refuge measures or management arrangements where flood access is a concern.
Surface-Water Management
Controlling runoff through suitable drainage, storage and discharge arrangements.
Flood Warning and Management
Operational measures, warning arrangements or emergency planning where these form part of the risk strategy.
How the Flood Risk Assessment Process Works
The assessment starts with a review of the proposal, planning requirement and available site information.
Initial Review
Confirm the site, proposal, planning requirement and available supporting information.
Data Review
Review flood maps, local evidence, watercourse information and relevant strategic documents.
Risk Appraisal
Assess the likelihood, depth, source and potential impact of flooding.
Mitigation Design
Identify suitable floor levels, layout changes, resilience and drainage measures.
Final Assessment
Issue the completed Flood Risk Assessment for the planning application or condition submission.
Information Required for a Quotation
Provide the full site address, a description of the proposed development and the latest architectural drawings.
Please also send the relevant planning-policy wording, validation requirement, pre-application comments or planning condition, together with any available topographical survey, drainage information or previous flood reports.
Flood Risk Assessments for a Range of Developments
The assessment is adapted to the size, use, vulnerability and location of the proposed development.
Nationwide Flood Risk Assessment Service
One Stop Consult coordinates Flood Risk Assessments for residential, commercial and mixed-use developments throughout mainland UK. Each assessment is tailored to the relevant Planning Authority, site constraints and available flood-risk information.
Other Services Your Project May Require
Flood Risk Assessments are often coordinated alongside drainage, planning and environmental services.
Important Flood Risk Assessment Information
Flood Risk Assessment requirements vary between Planning Authorities, development types and individual sites. The scope, conclusions and recommended mitigation depend on the available data, proposed design, climate-change allowances and project stage. Additional modelling, surveys, drainage design or consultation may be required where the available evidence is limited or the risk is complex. One Stop Consult provides consultancy and coordination support through its specialist flood-risk and drainage consultant network.
Flood Risk Assessment FAQs
What is a Flood Risk Assessment?
It is a technical report assessing whether a development may be affected by flooding, whether it could increase flood risk elsewhere and what mitigation may be required.
Do I need a Flood Risk Assessment in Flood Zone 1?
It may still be required for larger sites, areas with surface- water or drainage concerns, certain changes of use or where local policy specifically requests one.
What types of flooding are considered?
The assessment may consider rivers, the sea, surface water, groundwater, sewers, reservoirs, canals and other relevant sources.
Does the report include drainage design?
A drainage strategy may be included or separately required, depending on the planning request and agreed scope.
Can you review Environment Agency flood data?
Yes. Available mapping, model outputs and other relevant flood information can be reviewed as part of the assessment.
Can an FRA help discharge a planning condition?
Yes. Where a condition requests a Flood Risk Assessment, mitigation update or drainage information, the report can be prepared around the wording of that condition.
Do you provide Flood Risk Assessments nationwide?
Yes. We coordinate suitable flood-risk consultants for eligible projects throughout mainland UK.
Request Your Free Flood Risk Assessment Quote
Complete the form below with the site address, proposed development and current project stage. Upload any available drawings, planning requirements, topographical information and previous reports so our team can review the project and coordinate an appropriate quotation.