A Research on the Ecological Operation of Reservoirs Based on the Indicators of Hydrological Alteration

Abstract

The conventional reservoir operation strategy considering hydropower production ignores the ecology of the downstream rivers and causes a series of environmental problems. To ensure the sustainable development of a reservoir, the operation strategy should consider both the economic benefits of the power station and the ecological benefits in downstream rivers, the key to which is to select suitable parameters for quantifying the ecological objectives of the rivers and incorporate them into the reservoir operation model. To this end, the ecological index (EI) based on the Indicators of Hydrological Alteration (IHA) was developed to reflect the ecology of the downstream rivers, and a reservoir ecological operation model that takes into account the power generation capacity of the power station and the degree of hydrological alteration was constructed, which can be solved using the Non-Dominated Sorting Genetic Algorithm II (NSGA-II). The results show that the mean EI values increase a lot, from 0.24 to 0.62, after the construction of reservoir, and the optimal reservoir operation strategy in each typical year can reduce the hydrological alteration significantly (the reduction rates of both the abundant and dry water years exceed 20%), while ensuring the hydropower production of the power station (the reduction rates of hydropower production are just 1.64%, 3.15%, and 3.16% for abundant, normal, and dry water years, respectively), which provides a good reference for restoring the natural hydrological situation of downstream rivers.