Flood Risk Assessment For Planning Applications
For Housing, Commercial & Industrial Developments
Our Flood Risk Assessment Reports
Our highly experienced chartered engineers and expert modellers ensure that our Environment Agency flood risk assessments are based on reliable data.
Our reports will be fully compliant with the Environment Agency, the local council and the National Planning Policy Framework. This will safeguard your development from flooding throughout its lifetime. The flood risk assessment cost is as follows:
How do we Work?
We will contact the Environment Agency and get to work on your report.
You receive a flood risk report showing our initial findings.
You can submit our report to register or validate the planning application.
We will obtain the flood levels or complete the river modelling within 4 weeks.
Resistance and Resilience Interventions
Access and Evacuation Plan
Surface Water Management Principles
Flood Compensations Calculations
Evaluation flooding from other sources.
Our Benefits
Our Flood Risk Assessment Methodology
We listen to and work with developers, contractors, communities, architects, planning consultants and the Environment Agency to develop sustainable flood risk interventions. Our work is a reflection of our ethics and our commitment to building a more inclusive and sustainable society. We are one of the leading flood risk assessment companies.
We obtain your development’s drawings, topographical survey levels in mAOD and site location.
We collect flood risk information for rivers, sea, surface water run-off, groundwater, critical drainage and reservoirs.
We evaluate the detailed flood risk information for all potential sources of flooding and create flood river modelling as required.
We consult the Environment Agency, water company and local planning authorities to obtain the relevant approval.
Our proactive engineers and modellers utilise their experience with and understanding of the complexities of flood management to provide your development with flood protection.
Other Services
Flood Risk Map Tool
We have created a flood risk map tool to determine the flood risk for your development. We have put together all of the relevant databases so you have all of the flood risk information at your fingertips. You can find the flooding history of your development with the postcode or by using the site address.
For example, you can identify the flood risk by town by using flood risk map Oxford or flood risk map London.
Check out this flood risk assessment map tool.
Frequently Asked Questions
Is a Flood Risk Assessment always required?
A flood risk assessment is required when the development is located within an area at a medium to high risk of flooding. The requirements of a flood risk assessment are underpinned within the National Planning Policy Framework (NPPF) for developments. The aim of the NPPF is to move properties away from flood risk areas. The flood risk assessment should demonstrate that areas at low risk of flooding have been considered.
How does a Flood Risk Assessment get approved?
The Environment Agency approves Flood Risk Assessments using the recommendations provided by the National Guidance. The local council approves the Flood Risk Assessments for house extensions and areas located away from main rivers.
When is a Flood Risk Assessment required?
You can check our flood maps to see if you need a Flood Risk Assessment, we have included the Environment Agency flood map for planning within our tool. You can explore our maps using a flood risk post code check. The local authority will request a Flood Risk Assessment for your development site if it is located within Flood Zone 2 or 3 when trying to obtain planning permission.
You will also need a Flood Risk Assessment if your development is located within Flood Zone 1 but is affected by any other sources of flooding. Examples of other sources of flooding include: groundwater flooding, surface water run-off, or if your development is situated within a critical drainage area.
How long does it take to confirm the flood levels?
It takes 20 working days to get flood levels from the Environment Agency. This is the standard response time for a freedom of information request.
The flood modellers at the Environment Agency analyse their river models and supply the latest flood levels.
How is hydraulic model made?
A hydraulic model is a detailed mathematical representation of hydraulic equations that mimics the movement of water over a surface. The hydraulic models will provide the levels, velocity and volume of water. A hydraulic modeller uses either a 1D or 2D model to determine the water movement depending on the type of structures located within the watercourse of the flood zone.
How do I get the flooding history for a property?
To determine the flood history of a property, follow these steps:
- Obtain the address of the property and create a site location map.
- email to enquiries@environment-agency.gov.uk to provide your contact details and request flooding history. This service will usually cost £25.
- 20 working days later, you will be emailed the flooding history report.
If the property details are not available on the flood register, you can do the following:
- Check our flood risk map UK to determine if the property has been flooded in the past.
- Contact the local surveyors and property agents to request property details.
- Use the internet or local newspapers.
What does Flood Zone 2 and 3 mean?
How to check if a property is in a flood zone?
You can determine if your property is in the river flood zone in a number of ways:
- By consulting our flood risk map.
- By referring to the Environment Agency flood risk map for planning.
- By establishing if part of the development or property is located within the blue area i.e. Flood Zone 2 or Flood Zone 3.
- By obtaining the river flood levels (directly from the environment agency) and the property levels if the development is located within Flood Zones 2 or 3.
- By sending an e-mail to enquiries@environment-agency.gov.uk and requesting the Product 4 information. You must attach a drawing demonstrating the location of your property along with the post code.
- By employing a topographical surveyor to carry out a level survey or your house. The levels must be in mAOD.
- By comparing the levels of your property against the Environment Agency flood levels. Your property is in a Flood Zone 2 or a Flood Zone 3 if the flood levels are higher than your property levels.
We can assist you throughout this process and determine if your property is located within the flood zone. We can also help you to establish the best ways to protect your property against flooding.
Is my house at risk of flooding in the UK?
You can find out if your property is at risk of flooding in the UK by:
- Consulting our flood map UK which provides details of flood risk for rivers, surface water and reservoirs. You can even find if you area has been flooded in the past.
- Referring to the Environment Agency long term flood risk map including the surface water flooding map, the Environment Agency flood risk map for planning and the Environment Agency flood risk from reservoirs map.
- Getting in touch with your local council and requesting the surface water flood map for your location, as well as the information on the risk of groundwater flooding. You can also send an email to the local planning office or Highways Department.
- Using your postcode to find your local council on the gov.uk website.
- Sending an e-mail to: enquiries@environment-agency.gov.uk and making a request for the Product 4 information. You can then compare the river levels against your property levels.
It is impossible to determine with certainty if a property is at risk of flooding by consulting the maps alone. Your property can still be at risk of flooding even if it is situated on the border of flood risk areas.
The most successful way of establishing if your house is at risk of flooding is by comparing the levels of your property against the flood levels. You must then factor in climate change allowance to all of these levels.
The climate change allowance for England varies from 600mm to 1100mm. This will give you a better idea of the depth of a potential flood and will allow you to make advance preparations for a flood. These models are updated every three months and should be used only as guidance. It is important to recognize that flood events can be higher than estimated.
For example, in England the Environment Agency provides levels for 1 in 100 and 1 in 200 storm events. By comparison, in Germany and the Netherlands the levels are provided for 1 in 500 storm events.
We can assist you in identifying the level of risk your property is at and the steps you can take to protect against flooding.
Do canals flood?
Yes. Canals flood when the flood river levels are high and do not let the canal water have a free discharge. Canal floods are less likely to occur because the flow coming into the canal is in control. In spite of this, canals that do flood have a higher risk to users and to properties in the vicinity. The flood risks from canals are:
- Boats in the canal moving over the banks and affecting properties.
- The erosion of canal banks by flood water, leading to total failure of the bank. This can have catastrophic consequences to nearby properties.
- Water moving quickly over banks and affecting pathway users.
Although canal flooding is a possibility, canals are carefully maintained by the canal and river trusts, who invest substantially in the maintenance of waterways.
What is a high risk flood area?
In England, an area located within the Flood Risk Zone is classified as a high risk flood area. Flood Zone 3 is an area where the river flows and where flood water is stored. It is uncommon for basements and critical infrastructures to receive planning approval in these areas.
Will global warming cause floods?
Global warming increases the chances and consequences of flooding. This happens because a warmer atmosphere holds more water and thus causes heavier downpours in certain areas. Climate change brings less water to dry areas and more water to wet areas. Long dry spells ensure that already dry soils have les potential to absorb water quickly during torrential downpours. The models provided by the Environment Agency allow for a 30% and 70% climate change increase in flow. In some areas, this means that the current flood levels will rise by at least 600mm (2 feet)!
What should a flood risk assessment include?
A flood risk assessment should include the following:
- Site address and location.
- Review of the local Strategic Flood Risk assessment.
- Description and drawing of proposals.
- Evaluation of the site hydrology, geology and hydrogeology.
- Application of the sequential test or standing advice.
- Evaluation of flood hazard assessments from rivers and sea (including flood levels from the EA), canals, surface water run-off, sewer flood and groundwater.
- Management of the flood risk. This involves flood resilience and resistance interventions, site access and progress evaluation.
- Evaluation of the off-site impact of the flood risk. This usually involves the principles for surface water management, the conveyance of flood and the flood compensation storage calculations.
- Determining the residual risk. This includes site access and public safety, flood warning and evacuation or an emergency response plan.
You can check out our blog which provides further information on flood risk assessment template.
Do I need a Flood Risk Assessment?
You need a flood risk assessment if your development is in the Flood Zone 2 or 3 or if your development is greater than 1Ha located within Zone 1. You also need a flood risk assessment if your development is less than 1Ha and is affected by surface water, groundwater or located in a critical drainage area.
Do I need a Flood Risk Assessment?
How long does a Flood Risk Assessment take?
A Flood Risk Assessment takes 48 hours to complete without the flood levels. This Flood Risk Assessment will allow you to register the planning application. The complete flood risk assessment with levels takes 25 days to undertake as the Environment Agency releases the flood level information within 20 working days. Flood models can be ready within two weeks if the flood level information is not available.
What does Flood Zone 1 mean?
Flood Zone 1 means that the river flood level of risk for your development is low. It also allows the development to be completed without having to put together resilience and resistance interventions.
Can you build on Flood Zone 3?
It is possible to build on land located within Flood Zone 3. For example, you can expand your house or create a development that fully integrates the flood levels within the location and layouts of properties. Housing developments should pass the sequential and exception tests and provide evacuation routes located above the flood levels.
How do you mitigate flood risk?
The flood zone mitigation interventions depend on the depth of floodwater.
For instance, for shallow depth of water up to 300mm (1 foot), the best option is to keep the water out by locating the building above the flood levels. This can be achieved by building walls and floodgates or by raising the final floor level of your development above the flood level by 300mm.
When dealing with deeper water levels, you must account for building materials, foundations, walls, floors, services, fittings, doors and windows that minimize water entry and maintain structural integrity.
For water entry, you will need to consider materials and construction techniques that facilitate drying and cleaning.
Mitigation strategy must be in compliance with the “CLG 2007 Improving the Flood Performance of New Buildings publication” for new buildings and the “Preparing for floods, Interim Guidance for Improving the Flood Resistance of Domestic and Small Business Properties” for existing buildings.
What is a Compensatory Flood Storage?
A compensatory flood storage is the volume that your development takes from the Flood Zone. It is calculated for all developments within flood Zones 2 and 3.
The compensatory flood storage for both zones should be in compliance with the following requirements:
- It should be provided on level for level and volume for volume basis by gradually lowering ground levels. Flood water within the storage should flow freely out of the lowered area when flooding recedes.
- It should be located next to the Flood Zone wherever possible.
- The volume of the compensatory flood storage provided must be equal to the volume of floodwater displaced by the development.
What do I need to submit as part of the compensatory flood storage?
The following information is required as part of the compensatory flood storage:
- A site plan indicating the proposed and existing development.
- A map of the flood zone demonstrating the extent and depth of the flood area for the existing/proposed development.
- Calculations illustrating the proposed area of displaced flood water and the compensatory storage area.
- Cross-sections showing proposed and existing ground levels in relation to finished floor levels.
- A digital terrain model showing the flood in relation to the development.
