b'Validation of soil erosion risk maps using legacy and agency farm assessment dataBaggaley N1, Gagkas Z1, Dobbie K2, Carson A2, Lilly A11The James Hutton Institute, Aberdeen, AB15 8QH, UK, 2 Scottish Environment ProtectionAgency, Edinburgh, UKFor agricultural advisors, regulators and farmers to have confidence in risk assessment tools these tools require validation. While some soil erosion models have been validated usingmeasured erosion rates from plot studies or inferred rates from sediment loads in rivers, many remain un-validated due to a lack of data. In Scotland we have applied a simple rule-based soil erosion risk assessment (Lilly et al., 2002) which uses soil runoff potential from the Hydrology of Soil Types (HOST) classification, slope and topsoil soil texture and has recently been adapted to take account of land management. We have used a novel combination of observed erosion events from research studies and regulatory data from farm assessments undertaken byScottish Environment Protection Agency (SEPA) staff to validate the risk assessment. This approach ensures that the risk maps were salient to their end-users, credible for decision making and legitimate in their treatment of different views of risks associated with soil and land management with respect to protecting the aquatic ecosystem. This approach could be used as a key part of the SMARTER BufferZ project (funded by the Irish EPA) where we are developing both conceptual models of breakthrough points and a screening tool to assess areas of high risk of sediment and nutrient delivery to water courses. 17'