Influence of different activities on water quality in a small basin

Abstract The relative influence a city has on river water quality depends on the land use within the river basin and the character of the basin. In this paper the small Höje River basin, typical for southern Sweden, is studied; the pollution loading from a number of sources is estimated and the effect of actions taken both in the city and outside on river water quality is evaluated. The results show that agriculture is a major source of nitrogen to the Höje River; however, phosphorus concentrations are largely influenced by urban discharges (storm runoff and treated wastewater) and urban storm runoff carries major loading of heavy metals. Treatment of agricultural runoff or replacement of agriculture with less intensive land use (e.g. forestry, less intensive agriculture) would have the largest relative effect on river nitrogen status. Treatment of urban storm runoff would contribute to minimising heavy metals loadings to the river.