What is a flood risk assessment?
A flood risk assessment (FRA) evaluates the potential flood risks associated with a specific area or development project. It involves identifying possible sources of flooding, such as rivers, coastal areas, or surface water, and assessing the likelihood of flooding based on historical data and current conditions. The FRA identifies the potential impacts of flooding on people, property, and the environment and proposes mitigation measures to manage or reduce these risks on site. It also verifies developments comply with current regulations and planning policies related to flood risk to the local council and relevant stakeholders. The assessment will consider any remaining risks after mitigation and includes plans for emergency response in case of a flood.
When are flood risk assessments needed?
Flood risk assessments (FRAs) are required in development and land use planning. They are needed for new construction projects, particularly in areas prone to flooding, and are a mandatory part of the planning application process if the site is within a designated flood risk zone or near water bodies. Significant alterations or extensions to existing buildings in flood-risk areas may also require an FRA to evaluate the impact of flood risk. Changes in land use, such as converting greenbelt or brownfield sites for construction, may require an FRA to assess associated flood risks alongside Geotechnical and Environmental Investigations. Larger infrastructure projects, like roads or bridges near water, often need an FRA as part of their Environmental Impact Assessment. Local planning authorities or government regulations may also need FRAs for specific projects or locations so that potential flood risks are adequately addressed before further construction.
When you don’t you need a flood risk assessment?
In the UK, you generally don’t need a Flood Risk Assessment (FRA) when your development is in an area that is considered to have a low probability of flooding, such as Flood Zone 1. This zone is characterised by a low flood risk, with less than a 1 in 1,000 annual chance of flooding. However, even in this zone, an FRA might be required if your site is larger than one hectare or if your development could increase flood risk elsewhere. Ultimately, it is crucial to check with your local governing authority or a local environment agency, as specific local conditions or policies might still necessitate an FRA even in cases where it is typically not required.
What about minor developments, do they need a flood risk assessment?
For smaller projects, like minor extensions or alterations that do not increase the size of existing buildings, an FRA is typically not necessary, especially if the site is located within a Flood Zone 1 area. Similarly, if your development involves a change of use that doesn’t increase the flood vulnerability, like converting a commercial space into residential use in a low-risk area, an FRA may not be required. However, it is still important to check whether an FRA is needed with a specialist.
Why are flood risk assessments needed?
Flood risk assessments (FRAs) are crucial for several reasons. They help identify sites that are prone to flooding, preparing measures that protect lives and reduce property damage. FRAs play a key role in environmental protection by guiding development away from sensitive areas and preventing habitat loss and pollution. The assessment is required for regulatory compliance and policies so that developments are eligible for insurance and enable cost-effective planning, minimising potential flood-related losses. FRAs create informed land use decisions based on the unique situation of the site whilst contributing to sustainable development, considering long-term risks like climate change.
What is the flood risk assessment process?
The flood risk assessment (FRA) process begins with site evaluation, where data on location, topography, hydraulic modelling and historical flood events is collected to determine if the site is in a flood-prone area. The next step involves analysing potential flood hazards by identifying sources of flooding, assessing flood extent and depth, and studying flow paths. Following this, a risk assessment is conducted to evaluate the likelihood and impact of a flood and the vulnerability of the site. Residual risks are considered, and emergency response plans are developed for scenarios where mitigation measures might fail or extreme events occur. The entire process is documented in a FRA report, which is submitted to authorities for review and approval. Once approved, the mitigation measures are implemented during development, and ongoing monitoring ensures that flood risks remain managed effectively over time. This process ensures that potential flood risks are comprehensively assessed and managed to encourage a safe and sustainable future for the development.
How can flood risk be managed and mitigated?
A variety of strategies are employed to address and manage flood risk. “Hard engineering” methods involve using construction techniques to prevent flooding. This can include building walls, flood barriers, and embankments to safeguard areas at risk. Another method of defence is “soft engineering” which uses natural processes to mitigate flood risk. This approach might involve restoring river meanders, modifying land management practices, creating salt marshes, and applying broader nature-based solutions. “Property-level resilience” encompasses both hard and soft measures. This includes “resistance” measures like installing flood doors and barriers, as well as “resilience” measures such as raising electrical outlets above potential flood levels. Preparing a site before construction involves optimising the layout to minimise flood risk as well as incorporating surface water management techniques, such as Sustainable Drainage Systems (SuDS), to increase runoff management and reduce surface water accumulation.
What are the different flood zones in England?
Flood zones are categorised based on the likelihood and severity of flooding, helping to guide land use and planning. Flood Zone 1 represents areas with a low probability of flooding, with less than a 1 in 1,000 annual chance of river or sea flooding, indicating a minimal risk. Flood Zone 2 covers areas at medium risk, with a flooding probability between 1 in 100 and 1 in 1,000 annually for rivers, or between 1 in 200 and 1 in 1,000 for the sea. Development in these areas typically requires a Flood Risk Assessment to address potential impacts and mitigation measures. Flood Zone 3 indicates areas at high risk of flooding, with a probability greater than 1 in 100 annually for rivers or more than 1 in 200 for sea flooding. This zone is further divided into Flood Zone 3a, where high flood risk exists, and development is generally limited, and Flood Zone 3b, the functional floodplain, where development is highly restricted to maintain the floodplain’s role in flood management. These classifications help manage flood risk effectively and guide appropriate development practices.
Can I prepare a flood risk assessment myself?
You might consider handling it yourself if you’re dealing with a simple, low-risk project, such as a house extension in an area not prone to flooding. However, it’s important to also take into account surface water drainage and verify whether your site is in a location flagged for critical drainage concerns. We offer services to ensure your planning application is backed by the necessary risk assessments and documentation from the early stages of the process. Our team has extensive experience across various sectors – including residential housing, commercial developments, educational facilities, healthcare, blue light facilities, and structural engineering.
How long does a flood risk assessment take?
Flood risk assessments take several weeks to complete. However, the actual duration of the assessment is governed by the complexity of the flood risk, scale of the development and time taken to receive responses from statutory bodies. Detailed site surveys are often required to complete the report. Flood risk assessments need to consider the impact of the proposed development on future flood risk to the wider environment.
Appointing a flood risk consultant
Whether you’re working on a small or a large-scale development, we provide solutions that are both practical and cost-effective. We ensure that all necessary documentation is prepared for approval. We keep you informed at every step of the process, explaining our findings in clear, understandable terms to the highest standards, giving you confidence when submitting your application. Our esteemed reputation for thoroughness and accuracy is something we’re proud of, and we’re happy to provide references or examples of our previous work. We’re here to assist – even after the assessment is complete, offering guidance and support as needed for your development.
How can Sutcliffe help?
Our chartered engineers and flood risk specialists will work closely with you to deliver a comprehensive and detailed flood risk analysis that will ensure the safety and increased lifespan of your development.
To seek further advice and support with your development, please don’t hesitate to get in touch by filling out our contact form, emailing us at enquiries@sutcliffe.co.uk, or by telephone at 0151 227 3155.
