Integrated Water Resources Management for Nazlou Chai sub basin at future condition by RIBASIM Model

Iran is on arid and semiarid world belt so there are period's drought events therefore our country faces to with water shortage in agriculture, municipal, industrial and environmental water demand. Many efforts do for decrease bad water shortage effect in the country to be responsible for different demands. Integrated Water Resources Management (IWRM) is one of the activities to be performed. Goal of IWRM is to balance supply and demand somehow minimum demand prepare for all stakeholders. To achieve this goal need to use of resources and consumptions simulation tools. Simulation provides suitable tools for sustainable use of present water resources. This tool facilitates analysis and estimation economic-social effects about different scenarios water resources management with simulation resources and consumption and water budget determination at different region (sub basin). In this paper attempt with use of Ribasim software designed simulation model water resources supply and demand at Nazlou chai sub basin in Uromia river basin. With use of rainfall and discharge time series data (35 year), evaporation, monthly average ground water exploitation data, different consumptions monthly data of agriculture, municipal, industrial and environmental water demand and inflow to lake are simulated and priorities of resources and consumptions are designated, and results of demands supplying and shortage are available at program output. At this point, two possible scenarios were defined for the future of the Nazlou chai sub basin at the year of 1400. In the future, the system of Nazlou dam is included for supplying of agriculture, domestic and industrial water demands that increased due to population growth. However, environmental requirements are added to the system. In this study, failure to supply more than 4% for drinking and industrial water needs and the failure to supply more than 10 percent for agricultural purposes are acceptable. In the first scenario agricultural development is prior than environmental water demands. In this scenario, have the first priority, agricultural water supply has second priority and the third priority is related to the environmental requirements. The reason for choosing this scenario is surveying amount decrease of water entering to the lake. As observed, the amount of water entering to the lake in the dry and wet year respectively is 108/19 and 604/21 million cubic meters. However, in the case of total loss of about 4/25 of million cubic meters As a result, about 96% of the total water requirements is supplied and deficit amount is less than the acceptable range. In the second scenario, drinking and industrial water demands id prior than environmental water demand and aquaculture, and the third priority is agricultural water supply. In this scenario, environmental water demands is a higher priority than before. As observed, In this scenario than the first scenario, there is not much difference in the supply, however deficit in the agricultural sector than the first scenario is slightly decreased. Since the environmental water demand than the agriculture sector has a higher priority, thus, the amount of water entering to the lake is more than in scenario 1.In this scenario, the amount of water entering to the lake in the dry and wet respectively is 129.71 and 606.53 of million cubic meters. Based on the results, since the river basin downstream Nazlou divided into several branches, and calculate the inlet to the lake in this case would not be accurate, it seems that the construction of the last section of river gauging stations is necessary. The actual amount of water entering the lake by more accurately is measured. Since the life of the Uromia Lake is faced to seriously threat for various reasons, including increasing cultivation, dam construction and figure on the policies which following to restore the lake, the first scenario is not applicable.