Reliability, trade‐offs, and water resources development modeling with multiple crops

A hierarchy of models is developed to aid management and planning decisions in multicrop water resources systems located in higher latitudes of the world and featuring significant downstream requirements. A major objective is to quantify trade-offs between systems with a high reliability of water supply but low average benefits and those of low reliability with high average but also highly variable returns. Linear programing is used to select best crop combinations for given quantities of water available over the summer, associated water usage, and revenue estimates. A simulation model predicts changes in reservoir storage resulting from inflows and releases to meet requirements of crops selected by the linear program. Interseasonal water allocation is then optimized by using dynamic programing. A method is presented for determining variance of benefits as a function of system design parameters and downstream requirements. In an application to a water resources system in Montana, downstream water requirements and penalties were found to have a large effect on high reliability-low reliability trade-offs.