Pollution loads and surface water quality in the Kızılırmak Basin, Turkey

Abstract

A detailed study on the calculation of pollution loads and surface water quality classification was one of the most important outputs of the project on the preparation of watershed protection plans for the Kızılırmak Basin. For this purpose, the pollution loads for chemical oxygen demand (COD), total suspended solids, total nitrogen, and total phosphorus (TP) were calculated. The water quality classes of surface waters were determined based on Turkish regulations using the data obtained by the State Hydraulic Works between the years 2003 and 2009. The pollution loads and the surface water quality of rivers were displayed as maps using the geographic information systems. The connection between point and non-point pollution sources and water quality was examined. According to the obtained data, the main factors, which lead to environmental pressure on the surface waters in the Kızılırmak Basin, are non-point-source pollution originating from widespread agriculture and livestock breeding, solid waste dumping sites, and excessive salinity due to the natural formation and point-source pollution due to untreated domestic and industrial wastewaters. As a result of these pressures polluted rivers, namely Acıçay, Delice, Sarımsaklı, Kırşehir, and Yozgat creeks, were determined as hot spots in the basin. The water was polluted (Quality Class III) or highly polluted (Quality Class IV) in these rivers as measured by parameters such as COD, biochemical oxygen demand, ammonium nitrogen (NH4-N), TP, total dissolved solids, sulfate (SO42-), and sodium and chloride ions (Na+, Cl-).