Preliminary Flood Risk Investigation and Scoping
If you’re looking at a prospective site for development, or simply considering an extension on a property, it is highly recommended that you are in possession of all the relevant flood risk information prior to incurring development design costs.
The scoping phase will help determine whether a project is likely to be feasible, and if so, what considerations are required.
The preliminary assessment includes in-depth desk studies analysing the likely areas of high flood risk with regards to factors such as an area’s location, the topography of the land and the underlying geology. This will allow us to assess where flooding is likely.
Overview: What’s involved?
- Request modelled flood level data from the Environment Agency (EA) Scottish Environment Protection Agency (SEPA) or Natural Resources Wales (NRW), where available.
- Consultation with the EA to confirm requirements for development which could include:
- – Additional hydraulic modelling.
- – Flood storage compensation.
- – Flood mitigation measures.
- – Finished floor levels.
- – Flood Evacuation Plans.
- Review site and wider area topography through provision of a topographic survey or LiDAR.
- Comparing topographic survey levels across the site with flood level data (if available) and calculating predicted flood depths for key events, including the appropriate allowances for Climate Change for the design flood event.
If flood level data is not available, we shall undertake analysis of the Flood Zone extents against topographic levels to determine approximate flood depths for the 1 in 100 year and 1 in 1,000 year events. It should be noted that we would not be able to assess the impacts of climate change through undertaking analysis of Flood Zone extents against topography using this methodology;
- Review flood risk information from the Lead Local Flood Authority (LLFA) in relation to the site and any historic flooding. The assessment will include a request for information and a comprehensive review of local and regional flood risk documents and flooding reports.
Review LLFA requirements for surface water drainage for proposed development. At the preliminary stage this would include reviewing the latest LLFA guidance and identifying what design standards may need to be adhered to as part of any development.