Estimating Agricultural Water Consumption impacts on water level fluctuations of Urmia Lake, Iran

Urmia Lake located in northwestern Iran is currently facing a critical situation where climate change, drought, and by a greater extent recent developing projects in water consumption areas (mainly agricultural) have endangered the whole existence of the Lake. In such a circumstance, proper simulation of water resources and demands of the basin may help to find effective solutions for saving the Lake. Therefore, a recovery plan for Lake Urmia would include the accurate assessment of the amount and impacts of agricultural water consumption, as the main water user of the basin. In this respect, the historical data must be investigated after gathering them from various sources in order to assess their impact on the lake level fluctuations. Since monitored databases may not be available in most of developing countries, in this paper, the impact of agricultural water consumption on Urmia Lake level fluctuations is investigated. To accomplish this task, a method is also proposed for estimating agricultural water consumption in the absence of monitored data sets. For this purpose, the main basin is divided into several sub basins and characteristics of irrigated areas along with water balance components in each sub basin are determined using satellite images, site visits and database. Then the Water Evaluating and Planning system (WEAP) software is used to simulate the water resources system of the Urmia Lake basin and evaluate the impact of agricultural water use on the Lake level. Achievements of this study show that the agricultural water consumption and its recently growing rate play an important role on Urmia Lake level fluctuations and the Lake ecosystem. It also reveals that through an improved irrigation system the Lake level could rise substantially by saving water from higher irrigation efficiency. It is obvious that the impact of improved irrigation efficiency is granted assuming that the extra water saved through this procedure is returned to the Lake and not used for further developments.

Keywords:

Agricultural water consumption , Urmia Lake Basin , Lake level Fluctuation , Irrigation efficiency , WEAP