The Environment Agency has in the last month published new guidelines on how Climate Change should be considered in Flood Risk Assessments.

Consideration of potential climate change impacts on river flow, rainfall, sea level rise and wave heights is important to ensure that development is prepared for future conditions, and that the people who live in or use the developments are safe.

The new approach acknowledges the uncertainty around climate change predictions, and so uses a risk based approach. This means that where more vulnerable development is proposed, and where it is located in higher risk zones, more extreme estimates should be used, so that additional resilience is built in to the development design.

For developments where river flows may not be a consideration, drainage assessments will need to take account of ‘central’ and ‘higher’ estimates of rainfall intensity to ‘understand the range of impacts’. This is known as sensitivity analysis and can give additional nuance to the understanding of flood risk and adequacy of infrastructure capacity.

The full guidance note is available here: https://www.gov.uk/guidance/flood-risk-assessments-climate-change-allowances

Johns Associates can provide a full range of hydrological, geomorphological and hydro-ecological services including flood risk advice and Flood Risk Assessments to support planning applications. We can also design SuDS and provide advice on resilient design as well as undertaking flow monitoring, catchment scale studies, and land drainage studies.