RDE 415 - WTP for Storm Overflows' rainfall target

Defra wishes to commission independent experts, eftec, through an established framework with CEH, to provide up to date benefits values for the IA, specific to the target, and one alternative target (zero spills each, on average, by 2050).

Key elements of the work • The Storm Overflow Evidence Project (Stantec, 2022) splits the benefits of reducing overflows into three main categories: river health, human health, and social value - the last of which captures "general satisfaction" and non-use values. All three categories are relevant, and the evidence supporting each could be improved with specific primary research. • At minimum Defra needs an update of the social value of reducing SO spills in England. We are content with advice from the consultants that it is more valid in this exercise to obtain a value for all 3 categories together. While that will mean that the individual impacts cannot be valued independently, it avoids potential double counting of impacts, issues of substitution between improvements, and income effects that might be present if the aspects were valued separately. • Minimum demographics should be included to ensure we have a representative sample of the England population e.g. gender, age, socio-economic group, and to enable analysis by water and sewerage company (WASC) area. • This survey will draw on the pilot question on SOs in the recent NWEBS phase 2 work, but more material will need to be developed to support the explanation of SO spills and impacts of reductions e.g. health and environmental consequences. • We accept the risk that the survey may produce unexpected results, for example due to emotive media coverage of the issue, and potential protest responses.

This contract was awarded by DEFRA.