EFFECT AND CONTROL OF POLLUTION IN CATCHMENT-AREA OF LAKE SAPANCA, TURKEY

Land-based point and diffuse pollution sources in the catchment area o f Lake Sapanca, Turkey, were investigated. The present and future dist ribution of pollution loads were evaluated in terms of nitrogen, phosp horus, biochemical oxygen demand, and pesticides. A methodology for th e estimation of pollution loads was presented; most of which were base d on ''unit loads.'' Presently domestic End industrial point sources d ominate over diffuse sources including fertilizers and pesticides from agricultural use, nutrient loads from forests and meadows, urban runo ff, and leachates from unregulated dumps of solid wastes. For the futu re, the aim of the control action is to maintain the sustainability of the water quality of the lake, at least at the second class of Europe an Community standards. Within this framework; urgent/short-term and m edium/long-term control actions will be exercised. In the urgent/short -term stage, simpler and natural ways of treatment will be employed. I n the medium/long-term stage an integrated collection and treatment sy stem will be put on operation. After completion of a proposed collecti on system and treatment plants to handle point sources, the control of diffuse sources will be more significant. Control of diffuse sources for the abatement of further deterioration of water quality then becom es the key issue to be emphasized in the Lake Sapanca catchment area. Diffuse sources control will be achieved by dividing the catchment are a into three major protection zones. Use of pesticides and fertilizers on agricultural land and all other activities within these protection zones will be accomplished according to control plans, which will be supervised by an institution established to be responsible of ail the activities within the basin.