Explicit Stochastic Procedure for Developing Reservoir Storage-Yield-Reliability-Vulnerability Relationships

In this study, refinements are introduced to the explicit stochastic Fletcher-Ponnambalam method applied to reservoir sizing, with a primary focus on the development of storage-yield-reliability-vulnerability (SYRV) relationships. Improvements to the original method include transitioning from annual to monthly analysis, providing insights into monthly reliabilities, probabilities of containment, deficit, spill, and statistical moments of storage. The model is further enhanced with estimates for monthly vulnerabilities, as well as first and second moments of deficit, spill and allocation, aspects previously unaddressed. To validate the model, historical natural flow data from the Sobradinho reservoir (Brazil) is utilized, and monthly simulations are conducted based on synthetic scenarios aligned with the Standard Operating Policy. The model’s performance is evaluated using metrics such as the error sum of squares and the mean squared error. Additionally, a residual sample (model minus simulation) is created to undergo parametric and non-parametric tests, confirming the adequacy of the model. The study also includes the development of SYR relationships and equations based on the model’s results.