Weather radar to predict exceedances of faecal coliforms

Weather radar data have been used in a project in Scotland to develop a methodology to improve real-time predictions of faecal coliform concentrations in bathing waters. Poor bathing water quality, characterised by high faecal coliform concentrations, is primarily caused by pollutants mobilised during wet weather in river and urban drainage catchments discharging close to beaches. This paper reports on a study carried out with data for two sites in western Scotland, Irvine and Saltcoats, where good quality radar data and a high number of water quality samples exist. The analysis shows that radar data improve on rain-gauge data in their ability to predict water quality at the beach for one site and are marginally poorer than rain-gauge data at the other site. This is an innovative use of weather radar within a system for managing water quality and points the way for similar approaches to meet the challenge of the European Union's bathing water and water framework directives.