Phosphorus Loading in the Frome Catchment, UK: Seasonal Refinement of the Coefficient Modeling Approach

• Published in: Journal of environmental quality Vol. 30; no. 5; pp. 1738 - 1746
• Main Authors: Hanrahan, Grady, Gledhill, Martha, House, William A., Worsfold, Paul J.
• Format: Journal Article
• Language: English
• Published: Madison American Society of Agronomy, Crop Science Society of America, Soil Science Society 01.09.2001; Crop Science Society of America; American Society of Agronomy
• Subjects: Agriculture; Applied sciences; British Isles, England, Dorset, Frome R; Catchments; Continental surface waters; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; England; Environmental Monitoring; Exact sciences and technology; Forecasting; Freshwater; Models, Theoretical; Natural water pollution; Phosphorus; Phosphorus - analysis; Poaceae; Pollution; Pollution, environment geology; Seasons; Sensitivity analysis; Sewage; Sewage treatment; Soil Pollutants - analysis; Turf; Wastewater treatment plants; Water Pollutants - analysis; Water treatment and pollution; England; United Kingdom; Great Britain; Europe; European Union; British Isles, England, Dorset, Frome Catchment; Load; Drainage basins; Stream discharge; Phosphorus; Quantity; Forecast model; Modeling; Reduction; Diffuse source; Seasonal variation; Surface water; Nutrient; Stream; Water pollution; Waste water purification; Waste water discharge; Point source
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2001.3051738x

ABSTRACT This paper describes the results of an export coefficient modeling approach to predict total phosphorus (TP) loading in the Frome catchment, Dorset, UK from point and diffuse sources on a seasonal (monthly) basis in 1998 and on an annual basis for 1990–1998. The model predicted an annual TP load of 25605 kg yr−1, compared with an observed (measured) value of 23400 kg yr−1 Monthly loads calculated using the export coefficient model agreed well with monthly observed values except in months of variable discharge, when observed values were low, probably due to infrequent, and therefore unrepresentative, sampling. Comparison between filterable reactive phosphorus (FRP) and TP concentrations observed in the period 1990–1997 showed that trends in FRP could be estimated from trends in TP. A sensitivity analysis (varying individual export coefficients by ±10%) showed that sewage treatment works (STWs) (3.5%), tilled land (2.7%), meadow–verge–seminatural (1.0%), and mown and grazed turf (0.6%) had the most significant effect (percent difference from base contribution) on model prediction. The model was also used to estimate the effect of phosphorus stripping at STWs in order to comply with a pending change in the European Union wastewater directive. Theoretical reduction of TP from the largest STW in the catchment gave a predicted reduction in TP loading of 2174 kg yr−1 This illustrates the value of this seasonal export coefficient model as a practical management tool.