Assessment of water demand reliability using SWAT and RIBASIM models with respect to climate change and operational water projects

Abstract

Reliability assessment in the allocation of water resources under the changing climate condition has invaluable importance in planning the water demand at the basin scale. This study details an integrated framework for evaluation of the reliability between water supply and demand under climate change scenarios in the Zarrineh Rood River basin in the northwest of Iran. Initially, recorded climatic data in six synoptic stations are downscaled and projected for the period 2020–2040 based on the 14 GCMs using the LARS-WG method. Afterwards, the SWAT model is used to simulate the basin hydrology with consideration to the baseline and future climate periods at six hydrometric stations. Finally, the available water is allocated using the RIBASIM model based on the current supply-demand chain and predefined governmental water allocation rules for different sectors. Results showed that under climate change, the total runoff of the basin and the entrance catchments to the Zarrineh Rood River dam would decrease about 8% and 28%, respectively. The reliability of the water supply for joint drinking-industrial and agricultural demands would also decrease from 96.4% to 93.4%, and 90.2–89.5%, respectively. As such, the average annual streamflow from the Zarrineh Rood River ending to Lake Urmia will reduce by 10% if the operational water projects remain active.