Spatial prioritisation of catchments suitable for using Natural Flood Management

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The spatial prioritisation focuses on identifying catchments where there are properties at High & Medium flood risk as identified by the National Flood Risk Assessment. The following analysis of data was undertaken for all Water Framework Directive water bodies within each Environment Agency Area. 1. The number of residential & non-residential properties at High (1:30) & Medium (1:30 -1:100) levels of flood risk from fluvial/surface waters were identified in all current Water Framework Directive water bodies. This highlights where the public benefits can be achieved, i.e. where there is people and property at risk of flooding which could be reduced or managed by NFM. 2. The next step was to identify the total catchment area of agricultural and non-agricultural rural land (woodland etc) within every WFD WB and also in the catchments upstream of that WB. This identifies those smaller catchments with a significant area of agricultural land which could be utilised to reduce the risk of flooding. It also excludes urban catchments with large number of properties at risk of surface water flooding. 3. “Coastal Catchments” identified with no upstream areas were excluded i.e. they have been designated to focus on coastal waters and therefore properties are largely at risk of coastal flooding as opposed to fluvial flooding. Analysis of the above information enabled identification of smaller catchments with significant areas of upstream agricultural/rural land corresponding with areas with the largest numbers of people and property at high & medium risk of flooding. These have then been ranked to prioritise them. The highest ranked being the smallest catchments with the highest density of residential & non-residential properties at High/Med risk of fluvial and surface water flooding. The lowest ranked are large catchments with smaller number of properties at high and medium risk. We excluded properties at low and very low risk and also properties at risk from flooding from the sea from our analysis. Finally, we removed all water bodies with less than 50% of land identified as “Rural” to exclude water bodies primarily in urban settings. This was done as the prioritisation is primarily aimed at interventions of relevance to rural settings such as ELMs, Woodland creation and peatland restoration. The top 33% of ranked catchments have been selected for prioritisation within each Environment Agency Area, with the second third of medium priority and the lower third of low priority. Additional prioritisation catchments: Where not already identified for prioritisation through the above method the following catchments have been added to the prioritisation maps: a. Catchments participating in the Defra Natural Flood Management programme b. Catchments identified by Environment Agency Area Flood & Coastal Risk Management teams as a local priority following consultation