Abstract
This study is concerning the planning and decision making process of water resources projects under uncertainty. It includes a mathematical analysis to optimize the operation of the Mosul reservoir sought to achieve two conflicting goals, diverting water from for irrigation and releasing water for hydroelectric generation. Four methods of solutions have been implemented. These are: weights, constraints, goal attainment, and step method. The results reveal that the used methods gave the optimal solution by allocating 5906 million cubic meters/ year for irrigation and 1600 Gw-hour/year for power generation ),(6236, 1555), (6188, 1558),and (6121,1568) under the given inflow conditions . The current study suggested that the average value of these solutions i.e (6113, 1570) can be taken as a compromise solution to the problem. It is believed that this solution has a good chance to be selected by the decision-maker, because it contains the least possible degree of subjectivity.