Sources of nutrients in rural lowland headwater catchments and their ecological significance.
Abstract
Monitoring of storm run-off and streams in seven small (<10 km2) rural catchments in England and Wales suggests that surface and sub-surface run-off from agricultural land is not the only source of P contributing to the risk of eutrophication. Farmyard run-off, road run-off and discharges from septic tanks were all more concentrated sources of phosphorus (P) than run-off from farmed land. The more continuous delivery of P in run-off from impervious surfaces and/or in direct piped discharge of wastewater to the streams during the ecologically sensitive summer period suggests these sources need to be urgently controlled in order to achieve the water quality goals required by the EU Water Framework Directive. Catchment management strategies to control P transfer require collective actions and not simply those associated with control of major point sources and farming.