| Description |
Tarbela Dam is the largest in Pakistan, providing significant fractions of the country's irrigation supply, hydropower generation, and flood control. The operation of Tarbela Dam has been based on maximizing the release of water for irrigation supply. This single objective approach has provided benefits for Pakistan but has not maximized the potential of Tarbela Dam for targeting multiple objectives and considering multiple criteria. In this study, a model was created with the Water Evaluation and Planning (WEAP) System and used to explore the impact of altering the operations of Tarbela Dam in terms of reliability, resilience, and vulnerability (RRV) for the three objectives of irrigation supply, hydropower generation, and flood control. The reservoir performance for the altered operations was compared to the performance following historical operations for both historical and projected future climate and water demand conditions. Simulation results show that a new proposed operations strategy tested under historical climate and water demand conditions would increase RRV by 17%, 67%, and 7%, respectively, for the water supply objective and 34%, 346%, and 22%, respectively, for hydropower generation compared to the historical reservoir performance. The flood control reliability would increase by only 0.3%. For projected future conditions, the proposed operations strategy would increase RRV by 7%, 219%, and 11%, respectively, for water supply and 19%, 136%, and 13% for hydropower generation. For flood control, the reliability would increase by only 2%, while resilience and vulnerability would decrease by 33% and 39%, respectively. The study confirms the potential to improve the ability to provide more reliable and resilient irrigation supply and hydropower generation, although not to reduce vulnerability. The inability to improve flood control performance by altering operations confirms previous studies documenting the need for increased storage capacity. The use of multiple objectives and the RRV criteria is recommended as an approach to guide Tarbela Dam operations. |
