Assessment of Ghoturchay River Environmental Water Right Using Hydrological and Eco-Hydrological Methods

Allocation of rivers environmental water right as missing link in sustainable water resources management in Iran is undeniable necessity to preserve existing ecosystems in its catchments and preventing the death of wetlands and lakes which have been feeding by the rivers. In this paper environmental Water right for Ghoturchay River, important sub basin watershed of Aras river, have been studied using 4 hydrological Methods (Tennant, Tessman, flow duration indicators, Smakhtin), and 2 eco-hydrological methods (Flow Duration Curve Shifting (FDCs) and Desktop Reserve Model (DRM)). Among these methods, FDCs in ecological class C has been chosen as an appropriate method because it’s had more adaptation to hydrological and ecological conditions of studied region than other methods and considering ecological limitations and its flexibility in wet and dry months. In order to maintain the Ghoturchay River at minimum acceptable environmental status (i.e. Class C of environmental management), average annual flows of 6.94 m3/s (48% natural flow of the River) are to flow in it. This study showed that, average annual flows of 6.5 m3/s arrives at the Aras River, which is approximately equal to the environmental water rights.