Water Resource Allocation Management and Dam Catchment Performance Evaluation Using the WEAP Model: A Case Study of Iran’s Bakhtegan Catchment

Meeting water demands with high reliability and allocation priority in watershed-delineated areas is an important challenge for decision-makers, especially in drought-prone regions. The purpose of this study is to evaluate the water consumption of a contiguous dam series including the Dorood Zan, Mulla Sadra, and Sivand Dams using the water evaluation and planning system (WEAP) model in Iran’s semiarid southern region. Here, WEAP is applied to these locations, separately as well as overall, to configure resources, costs, and other factors. First, for the separate location analysis, the reservoir capacity of every dam was investigated on a month-to-month basis for agricultural, drinking water, and industry uses regardless of other dams. Note that the water supply for demands relevant to environmental water right was not supplied because it has not been an important priority of water resource managers. Second, overall water demand, i.e., water demand for all dams combined, was evaluated by a monthly, simultaneous assessment of water supply at downstream demand points behind each of the dams. The coordinated operation has improved the condition of the downstream points; when a reservoir is not able to supply its downstream points, it can be met by releasing water from upstream dams. It was found that in case of the central Sivand Dam during successive drought years, water resource planning to meet the needs of downstream was highly problematic, especially with regard to agriculture usage. Furthermore, for continuing drought periods, drinking water needs only can be supplied. A flexible and well-balanced combination of surface and groundwater use is a key to treat water resource management, and, in times of drought, underground water resources can be utilized to meet water needs, especially in the months of low water.