Ecologically-friendly operation scheme for the Jinping cascaded reservoirs in the Yalongjiang River, China

Abstract

Ecologically-friendly reservoir operation procedures aim to conserve key ecosystem properties in the rivers, while minimizing the sacrifice of socioeconomic interests. This study focused on the Jinping cascaded reservoirs as a case study. An optimization model was developed to explore a balance between the ecological flow requirement (EFR) of a target fish species (Schizothorax chongi) in the dewatered natural channel section, and annual power production. The EFR for the channel was determined by the Tennant method and a fish habitat model, respectively. The optimization model was solved by using an adaptive real-coded genetic algorithm. Several operation scenarios corresponding to the ecological flow series were evaluated using the optimization model. Through comparisons, an optimal operational scheme, which combines relatively low power production loss with a preferred ecological flow regime in the dewatered channel, is proposed for the cascaded reservoirs. Under the recommended scheme, the discharge into the Dahewan river reach in the dry season ranges from 36 to 50 m 3 /s. This will enable at least 50% of the target fish habitats in the channel to be conserved, at a cost of only 2.5% annual power production loss. The study demonstrates that the use of EFRs is an efficient approach to the optimization of reservoir operation in an ecologically friendly way. Similar modeling, for other important fish species and ecosystem functions, supplemented by field validation of results, is needed in order to secure the long-term conservation of the affected river ecosystem.

River Damming Impacts on Fish Habitat and Associated Conservation Measures

“…However, many studies have shown that by optimizing the operation of reservoirs, the ecological benefits can be ensured with a marginal loss, or even an increase of socio‐economic benefits. Under the optimal operation scheme, the Jinping cascade reservoirs in the Yalong River, China, only sacrifice annually 2.5% hydropower production to conserve more than 50% habitat for Schizothorax chongi in the dewatered reach (D. Chen et al., 2014). In the upper Yangtze River, under an optimal operation scheme, the hydropower production loss of the cascade dams is only 1.76%, while the fulfillment of ecological flow increases 17.45%, which greatly promoted the spawning of FMCCs (Dai et al., 2022).…”

A shorter time step for eco-friendly reservoir operation does not always produce better water availability and ecosystem benefits

“…Eco-friendly reservoir operation aims to sustain ecosystem health for a regulated river, while sustaining socioeconomic interests (Harman and Stewardson, 2005;Suen, 2011;Large, 2012;Zhou and Guo, 2013;Chen et al, 2014). Due to the contrasting objectives of maximizing human interests and minimizing hydrologic alterations to protect riverine ecosystems, reservoir operating schedules need to be carefully considered (Tharme, 2003;Suen and Eheart, 2006;Richter and Thomas, 2007;Petts, 2009;Tsai et al, 2015).…”