Assessment of pressures and impacts on water quality of a small Mediterranean stream using an integrated approach

Water resources are under the threat of pollution from anthropogenic activities. The aim of this study is to present an integrated approach for analysis of pressures and impacts on the water quality. The application site is a small Mediterranean watershed, Acisu Stream, that is located in Antalya City of Turkey. This stream drains into the Mediterranean Sea and it has a high local impact on the sea water quality. An intense water quality monitoring program was conducted at twelve monitoring stations along the stream network with monthly intervals for a period of 1 y. The monitoring study involved onsite measurements and analyses of many physicochemical, bacteriological parameters and pesticides. The discharges of three wastewater treatments were the main sources of point pollution. The diffuse pollution of total nitrogen (TN) and total phosphorus (TP) were estimated on daily basis using MapShed watershed model and GIS. Cropland, septic systems and farm animals are the main sources of diffuse pollution. The areal loading rates of diffuse TN and TP were estimated at nearly 20 and 4 kg/ha/y. The contribution of cropland to TN and TP pollution loads was the highest among all sources and they were estimated at 58% and 67%, respectively. The pollution loads of TN (24.33%) and TP (21.99%) were also high for point sources. These pollution sources have an adverse impact on the water quality and there is a need for integrated management to improve water status both for the stream and the coastal water.