Existing reservoir infrastructure and operation policies are largely based on historical records, which may deviate from future projections. There are valid concerns regarding the enduring effectiveness of current infrastructure and operational strategies in the face of a changing climate. Climate change could amplify the opportunity cost of reservoir operation (evaporative loss), which is influenced by the complex interplay of hydrologic variability, reservoir characteristics and human decisions, and often overlooked. Disentangling and quantifying these impacts can benefit reservoir management strategy development to counter climate-induced challenges. Furthermore, it remains unclear whether reservoir storage reallocations can yield benefits. Our study focuses on the reservoir systems in Texas and pursues three primary objectives: 1) assessing how climate change alters hydrologic conditions and whether the current reservoir infrastructure and operation policies are sufficient to mitigate these alterations; 2) determining the impact of climate and operation policy on reservoir evaporative loss; 3) identifying the optimal strategies for re-operating existing reservoir infrastructure to enhance water supply performance without raising flood risks. The results reveal that current policies are largely successful in reducing flood risks by eliminating small floods, reducing peak magnitude and extending duration for large floods. Operation strategies can effectively reduce the risk of storage droughts for many cases, but the pressing issues of reservoir evaporation and sedimentation underscore an urgent need for revisions in the current guidelines to enhance system performance. Storage reallocation by raising the designated top of conservation pool illustrates potential benefits including improved resilience and reduced vulnerability. Our study also recognizes the role that sediment removal can play in maintaining the sustained operation of the system.
