Modelling the impact of future climate change on streamflow and water quality in Wales, UK
Richard Dallison, A. Prysor Williams, Ian Harris, Sopan Patil
Abstract
Climate change is likely to have a major impact on future hydrological regimes, impacting numerous sectors reliant on surface waters. We use the Soil and Water Assessment Tool (SWAT) to model future (2021-2080) streamflow and water quality variables (nitrogen, phosphorus, suspended sediment, and dissolved oxygen), in five catchments in Wales, under a worst-case scenario of future greenhouse gas concentrations (RCP8.5). Results show a decline in annual average flows (-4% to -13%) but larger changes seasonally (spring, up to 41% increase; autumn, up to 52% reduction). The magnitude and frequency of high flow events increases in spring (magnitude: Sen's slope range 0.165-0.589, p <0.01), with more low flows in autumn (Sen's slope range 0.064-0.090, p <0.01).