Changes in water quality of the River Frome (UK) from 1965 to 2009: Is phosphorus mitigation finally working?

► Complete water quality data from unique 44 year monitoring programme presented for the first time. ► Increases in nutrient pollution from 1965 to 1990 increased river productivity. ► Improvements in sewage treatment have reduced P concentration, and improved river ecology. ► The timing of diatom blooms is closely related to temperature. ► Full data set made freely available to wider research community.