Determination of ground water-surface water relation in Kayseri city Develi-Yesilhisar-Yahyali closed basin by using environmental isotopes

Project area is the closed basin which covers Yesilhisar, Develi and Yahyali districts, its drainage area is approximately 3200 km2 and plain area is 800 km2. Wetland area (Yay Lake, Sultansazligi reedfield, Coel Lake, Akar reedfield) which is found at the lowest elevation of the basin covers 100 km2 area. Sultansazligi is one of the most important bird habitat of Turkey. There is an irrigation water supply problems in the basin; because of the aridity also aridity is a danger for the lives of birds and the other fauna and flora which are living in the wetland. Water level of the reedfield had been decreased in the recent years. In this study Surface water- groundwater interaction is analyzed by using environmental isotopes; tritium, deuterium, oxgen18. Keywords: isotope hydrology, surface water-groundwater interaction