The contributions of natural and anthropogenic climate change on water resources reduction in Zarrinehroud basin of Lake Urmia

Human activities and climate change have reduced the inflow to Urmia lake and caused a sharp drop in its water level. This study aimed to identify the breakpoint of rainfall and runoff to evaluate the relative contribution of climate change and human activities in reducing runoff at the Zarrinehroud watershed. The Zarrinehroud basin is the largest sub-basin of Urmia lake with a considerable contribution to the water supply. The  30 years,1988 -2017, data of discharge and precipitation were used and analyzed using SPSS software. A breakpoint was found based on an analysis of the data in terms of homogeneity and trend.  The data before and after the breakpoint were considered undisturbed and disturbed, respectively. The spatial data were analyzed in the GIS environment. The hydrologic model HEC-HMS was used to simulate rainfall-runoff data in the studied watershed and was developed in the undisturbed period. The validated HEC-HMS model was used to quantify the effects of climate change and anthropogenic activities in the disturbed period. The results of rainfall and trend analysis showed a negative trend for stations and a breakpoint was chosen for all sub-basins. The results confirm that 30% of the changes were due to human factors. This number is lower than the values obtained for other Urmia lake sub-basins, indicating the lack of water resource development activities in this sub-basin.

The contributions of natural and anthropogenic climate change on water resources reduction in Zarrinehroud basin of Lake Urmia Keywords:

Urmia Lake , climate change , Precipitation , Break Point , HEC-HMS