Water Quality of Agricultural Drainage Systems in the Develi Basin in Turkey

Nutrients and/or pesticides used in agricultural areas are often responsible for reduced water quality. in this study, we analyzed the impact of agricultural activities on the water quality of the agricultural drainage in the develi basin, kayseri. develi basin is a closed agricultural basin located in the semi-arid central anatolia region. irrigation has long been practiced in the develi basin, but it has become more intense since the completion of the develi irrigation project in 1988. currently, about 30000 ha of agricultural land is irrigated in the basin and agricultural drainage is collected with a dense network of channels, which is eventually discharged into an ecologically important wetland, called the sultan marshes. water quality changes due to irrigation was evaluated based on surface water quality regulation using water samples collected from two irrigation reservoirs (kovalı and ağcaaşar reservoirs) and one drainage channel and two return flow pumping stations (ufaktepe and camızgölü pumping stations) for 24 month period. temperature, ph, dissolved oxygen and electrical conductivity, total nitrogen, total organic carbon, total phosphorus, nitrate, ammonium, chloride, sulfate and total suspended solids were measured. water samples from kovalı and ağcaaşar reservoirs were classified as class 1 (high quality water) while water samples from drainage canal and ufaktepe pumping station were classified as class ii (slightly contaminated water) and water samples from camızgölü pumping station, which is the station where almost all drainage waters are collected, were classified as class iv (very contaminated water). results showed that water quality deteriorated significantly after irrigation practices.