Large-scale risk screening of raw water quality in the context of drinking water catchments and integrated response strategies

Abstract

Water resources provide multiple services, one of the most important being the provision of drinking water, conventionally treated before public consumption as potable supplies. With increasing pressures through from land use and climate change, there are important advantages cost- and carbon emission controls to be achieved by resisting further decline and indeed improving gained from considering raw water quality by as a fundamental characteristic of the natural resource, and to anticipate emerging risks within themanaging catchments from an ecosystem-service perspective, catchments rather than relying on treatment. This research proposes asignals the power of large-scalenational-scale , rapid risk screening of raw water quality, coupled with catchment sensitivity - determined as the product of resistance to change and the degree of modification - enablingbased on catchment sensitivity to pressures as prerequisite to a more strategic inclusion of emerging risks in water resource and ecosystem management. As an application,Unprecedented access to raw water quality observations from parameters of 154 surface water catchments in Scotland were investigated to determine the national baseline and to identify current pressures and underlying drivers. Risk-based spatial relationships between catchment characteristics and raw water quality Patterns and spatial dependencies were investigated using a mix of methods including principal component analysis, cluster analysis, and multi-target predictive clustering trees. These statistical approaches highlight the interaction between intrinsic catchment biophysical properties, land use and climate in characterising water quality risks and identify the focus for prioritising catchment interventions and risk-mitigation in the future. ation of actions including further analysis. The emphasis on raw water quality will also support an ecosystem-based approach to increase catchment resilience, in order to ensure long-term supply of good quality drinking water while simultaneously creating wider benefits for society and the environment.