Flood Risk Assessment Flood Zone 1
Flood Risk Assessment Flood Zone 1 evaluates the likelihood and impact of flooding in Zone 1. Flood zone 1 is one of the 3 Flood Zones defined by the Enviroment Agency. It is the lowest risk zone with less than 0.1% annual chance of river or sea flooding, and it is generally safe for developments without an FRA.
However, certain conditions can trigger a Flood Risk Assessment in Flood Zone 1, discussed below. RIDA Reports provide expert planning services, from quick flood risk appraisal for initial screening tests to full FRA for planning permission. Contact us today to discuss your project and find the right solution!
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Flood Zones Explained: 1, 2, 3 (and 3b)
England’s official flood map for planning by the Environment Agency has divided the land into three main flood zones:
- Flood Zone 1: This is the lowest risk zone with only 0.1% chance of flooding from the sea or river. Most developments are allowed here.
- Flood Zone 2: This zone has a medium probability of flooding with a 0.1-1% annual chance of river flooding and a 0.1-0.5% chance of coastal flooding. All development here needs careful consideration and a Flood Risk Assessment.
- Flood Zone 3: This zone has the highest risk of flooding, with 1% or greater annual chance of river flooding and a 0.5%+ chance of coastal flooding
Additionally, there is a flood zone 3b, a part of flood zone 3, where floodwater is allowed to flow or be stored. This zone is not explicitly shown on the main public map, but local plans and the strategic Flood Risk Assessment by RIDA Reports identify it. Development in flood zone 3b is highly restricted.
Kindly note that all developments in flood zone 2,3 or 3b usually require a full Flood Risk Assessment. In contrast, Flood Zone 1 is considered safe, but some site-specific factors can mandate a Flood Risk Assessment.
The Flood Map for Planning produced by the Environment Agency applies to England only. However, similar flood mapping systems are available in the other UK nations:
- Wales: Natural Resources Wales
- Scotland: Scottish Environment Protection Agency
- Northern Ireland: Department for Infrastructure
When Is an FRA Required in Flood Zone 1
A full FRA is not automatically required for small developments in Flood Zone 1, because it is considered a safe zone with the lowest chances of annual river and coastal flooding. However, the Environment Agency and Local Planning Authorities have set clear conditions which trigger a Flood Risk Assessment in Flood Zone 1.
Key triggers include:
- Large site size (≥1 hectare):
- Surface water flood risk:
- Critical drainage problems:
- Future flood risk (SFRA guidance):
Large Developments (≥1ha)
Development of 1 hectare or more in Flood Zone 1 requires an FRA. Even major developments like creating 10+ dwellings or 1000+ m² floor space also require a Flood Risk Assessment for planning permission.
A specialised Flood Risk Assessment in this condition ensures your design safely manages any flood source and will not increase the risk of flooding elsewhere. We at RIDA Reports quantify flood levels and drainage needs on large sites to ensure a compliant flood risk report.
Surface Water Flood Risk
Surface water is a major source of flooding in the UK. Hence, this source alone can trigger an FRA in flood zone 1 if official maps like RoFSW flag any part of the site at risk of surface water flooding. Additionally, if your site is in Flood Zone 1 has shallow drainage or a natural depression.
Critical Drainage Areas
Sites with areas officially designated as having critical drainage problems must submit an FRA along with the planning application for planning approval, regardless of being in a low zone designation.
A FRA in such conditions examines how your development might affect the local drainage and proposes Sustainable Drainage Systems ( SuDS) as part of the mitigation strategy. We offer drainage and foul water management, along with drainage consultancy, where our engineers tailor a solution specifically for your problems. Our Drainage Strategies are completed in 5 days.
Future Flood Risk (SFRA Guidance)
If local planning documents (the SFRA) indicate future climate change or new modelling will put a now safe site into a higher risk of flooding during its lifetime, you need an FRA for development in such sites.
Our flood risk reports in such cases check for future scenarios to predict flood risk throughout the development’s lifetime and proper mitigation strategies which reduce the given flood risk and protect the development for its lifetime.
Checking Flood Risk in Flood Zone 1
Official flood maps: Go to Floop Map for Planning by the Environment Agency and confirm your flood Zone. You can check your flood zone by adding your postcode or grid reference.
Local data and SFRAs: You can review the Local Planning Authority’s Strategic Flood Risk Assessment or local plans. These reports can show detailed flood data and any future flood risk at the site.
Flood Risk Appraisal: A Flood Risk Appraisal is a technical report that examines all flood sources and performs a screening test of the site to check if a full Flood Risk Assessment might be required at the given site. RIDA Reports perform a Flood Risk Assessment for development of any size, starting from £750.00, and you will receive your draft within 24 hours
Rainfall and climate projections: For long-term planning, consider future climate change allowances. The NPPF/EA climate change official guidance provides percentage increases in flood levels for 20, 50, and 100 years ahead. An engineer can calculate how higher flood levels might affect your development over time if your site’s exposure to rivers or the sea is marginal.
Consult experts: You can speak with local planning authorities, and even RIDA Reports, to get advice on whether your project needs an FRA or not!
RIDA Reports’ Flood Risk Appraisal starting from £750
A flood risk appraisal, also known as a preliminary appraisal, is a short report to check whether your site actually needs a full FRA. We provide a flood risk appraisal draft report within 24 hours,s and it starts from £750. Our flood risk appraisal covers:
- Site Flood Zone identification using the Environment Agency map and local sources
- All relevant flood sources : (river, coastal, surface water, groundwater, reservoirs, etc.
- Local Plans and SFRA notes on future flood risks
- Basic drainage and water concerns, such as soil type and planning history.
- Flood Risk constraints of your development
Our appraisal is:
- Completed within 24 hours, and you will receive your first draft with all the important information
- If you decide to hire us for your Flood Risk Assessment service after a flood risk appraisal, we offer a 20% discount
- You can ask for one round of changes after receiving the initial report.
Flood risk appraisal can identify any deal-breakers. For instance, if the site is under 1 ha with no surface water risk and drainage issues, the report may confirm that a full FRA is not needed. A flood risk appraisal by RIDA Reports often pays for itself as it avoids unnecessary work and catches all issues early on.
Our Flood Risk Assessment Services
If you need an FRA after performing a Flood Risk Appraisal, RIDA Reports deliver a compliant Flood Risk Assessment ready for planning submission. Our standard FRA methodology includes:
- Site Analysis: We analyse your site and map all the flood sources using the latest Environment Agency models and local data.
- Flood Modelling: When required, we perform 1D/2D hydraulic modelling to refine flood levels and flood extents on the site. The modelling is key, especially when your sites are on or near a river or coastal area.
- Climate Change & Future: As we know, climate change plays a key role in future flood risk, so we include climate change allowances. For instance, we apply the EA guidance to increase the flood estimate depending on the region and flood type. This step ensures your site is safe for its development lifetime.
- Design Recommendations: Our FRA includes clear mitigation strategies and design recommendations. We might recommend finished floor levels, flood proofing, specific construction material, emergency entry and exit, etc., depending upon what suits your development the best for protection.
- Regulatory Compliance: Our FRA reports meet the National Planning Practice Guidance and address all the items in the EA checklist, for example, climate allowances and sequential tests. This maximizes your chance of planning approval on first submission.
We also provide other flood risk-related services, such as:
- Sequential test
- Sequential test
- Exception test
- Drainage Strategies
- Drainage Consultancy
Our engineers prepare FRA for all development types: residential, commercial, mixed-use and industrial in Zone 1,2, or 3. We offer fixed rates and provide a no-obligation free quote based on your project details. You can contact our flood risk consultants to get a quote or discuss your project in more detail.
Why choose RIDA Reports for Flood Risk Services
We deliver Flood Risk Assessment services for commercial, residential, industrial and mixed-use developments across England. Our engineers have 21+ years of experience in performing complaint Flood Risk Assessments and helping our clients in streamlining their planning process.
We cover developments from minor to strategic and provide mitigation measures tailored specifically for your development. Our work is based on the latest national data from the Environment Agency and NPPF guidance, national checklist for Flood Risk Assessment and advanced methodology.
Our Flood Risk Assessment reports are compliant and structured to address risks and propose mitigation strategies early on. On the other hand, our Drainage Strategies are sustainable and completed in 5 days. We also provide additional services such as sequential tests to meet national policies and prevent planning delays due to refusals.
We offer the fastest turnaround in the UK, as our initial FRA reports are completed in 48 hours, our flood risk appraisal is completed within 24 hours, and our drainage strategies are completed within 5 days. Check out our services with pricing here.
Speak to our flood risk consultants
Whether you need a flood risk appraisal or a Flood Risk Assessment, our team can help you with both.Iff you are still unsure what is best for your development in Zone 1, you can discuss your project with our consultants and discuss the best approach for your development.
Speak to our consultants today at 01608 510 121 or leave us a message!