Estimates of annual loads of phosphorus, sediment, nitrogen and faecal coliform from non-agricultural sources to rivers in Scotland, reported at Water Framework Directive (WFD) catchment scale. The sources of pollutants include: urban, woodland, montane areas, river bank erosion, septic tanks and sewage treatment works. Loads are estimated based upon available data (e.g. septic tank licences) and modelling (bank erosion). The values specify phosphorous, nitrogen or sediment losses in kilograms per year and faecal coliform in 10^6 colony forming units (cfu) per year.
Publication date: 2017-02-16
Non-agricultural pollutant emissions were calculated for each WFD waterbody on the basis of tabulated discharges and empirical models. Losses from septic tanks were derived from SEPA licensing records and per capita coefficients, whilst losses from sewage treatment works were derived from consented dry weather flows and average concentrations from compliance monitoring. Losses from urban areas were calculated using the Event Mean Concentration model of  whilst montane and woodland losses were calculated using the PLUS and MARS models ( and  respectively). Losses from bank erosion were calculated using a simple index of bank erosion that was calibrated against available sediment tracing data.
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