Untangling Pollution Sources in UK Rivers: A Catchment-Scale Approach to Water Quality Apportionment

Water quality in UK rivers continues to receive significant media attention, with ongoing concern around the impacts of both diffuse agricultural pollution and point-source discharges from wastewater infrastructure. Distinguishing between these sources remains challenging, despite continued monitoring and regulation. Sapphire Agriculture is a UK Space Agency (UKSA) funded project under the National Space Innovation Programme (NSIP). The project explores approaches to water quality apportionment at the catchment scale. The project aims to improve understanding of the relative influence of agricultural activities and wastewater infrastructure on observed water quality patterns. The intention is to support water companies in identifying where improvements to wastewater infrastructure may have a greater influence, helping to inform the prioritisation of investment. The work draws on a range of complementary datasets, including earth observation and in situ data, to provide an understanding of catchment conditions and pressures. These inputs are combined and used to develop machine learning approaches that are being investigated for their ability to support backwards-looking apportionment of historical water quality events. The project also considers the potential for short-term forecasting, incorporating weather information to provide insight into near-future water quality.