Optimal Design and Operation of River Basin Storage under Hydroclimatic Uncertainty

As populations and economies expand in regions with changing climates, demand for water can quickly grow beyond what natural supply can sustain. This paper proposes to mitigate shortages, such as those that occur along the Lower South Platte River in northeastern Colorado, via a three-step approach: (1) create flow data scenarios, which represent a wide array of hydroclimatic outcomes; (2) use an existing simulation model to process these scenarios in order to locate excess supply and unmet demand both spatially and temporally; and (3) minimize the cost of alleviating identified shortages using a new, multiperiod, two-stage stochastic programming model, which determines reservoir location, size, type, and operation over a 50-year time horizon. Results indicate that demand associated with historical and seasonally shifted scenarios can be satisfied, and unmet demand associated with more challenging reduced-mean runoff scenarios can be mitigated substantially. Furthermore, multiple smaller reservoirs are preferred over a single large reservoir to hedge against these uncertainties.