Author(s): Yi-Chen E. Yang
Linked Author(s):
Keywords: Reservoir reoperation; Ecohydrology; Watershed management; Lake Shelbyville
Abstract: Achieving environmental or ecological target for ecosystem restoration is one of the major reasons for reservoir reoperation. Traditionally, a minimum water release is set as a constraint for downstream ecosystem flow requirement. Today, re-establishing the natural flow regime to a practical degree is under consideration for reservoir operation and watershed management. The authors' previous work has created a quantitative relationship between the most ecologically relevant hydrological indicators (ERHIs) and a fish diversity index. In this study, those results are extended to incorporate the selected ERHIs and the quantitative relationship into a modeling framework. It demonstrates the implications of updating reservoir operation rules for both human water use purposes (such as water supply, flooding control, and hydropower generation) and ecological flow requirement. The multi-objective genetic algorithm (MOGA) is applied to determining optimum operation rules regarding two objectives: maximizing fish diversity as an ecosystem restoration target and minimizing flooding lost as an economic target. A daily reservoir water release generator is constructed with a flow generation module and a reservoir routing module. The flow generation module generates daily water release based on operation rules. The reservoir routing module, which considers historical inflow characteristics and reservoir capacity, tests the generated daily water release and maintains the mass balance of the reservoir operation. The generated daily reservoir water releases are used to calculate the fish diversity and flooding lost. The MOGA optimizes the operation rules which represented by a set of parameters. Lake Shelbyville, serves as a multifunction reservoir for flooding control, recreation, fish conservation, navigation and water supply located at central Illinois, is used to demonstrate the proposed modeling framework. The Pareto optima results are compared with the historical daily water release. Implications for reservoir reoperation are discussed using the results of the case study reservoir.
Year: 2009