The Variation of Hydrological Regime According to the Daily Operation of a Complementary Hydro-Photovoltaic Reservoir and Its Impact

Abstract

Daily operation of a hydropower station is conducted to meet the energy requirement. The hydraulic parameters of the downstream are significantly affected by the dam operation, which has a negative impact on the aquatic system. When the multi energy complementary method is used, such as hydro-photovoltaic (hydro-PV) combined power generation, the problem will worsen. Hydropower station A (HSA) on River X was selected to investigate the impact of daily operation. HSA is a part of hydro-PV complementary power generation. The spawning and breeding period of typical fish, April to July, was selected as the study period. According to various scheduling, the changes of hydrological regime were analyzed. The results show that the maximum flow variation was 334 m3/s, and the variations in water surface width and velocity during reservoir operation were between natural conditions. The maximum daily water level variations under the two operating scenarios were 1.6 m and 3.5 m respectively. The remarkable change of water level may have a negative impact on aquatic organisms. Considering the daily variation limit of 1.2 m under natural condition, the relationship between the allowable daily variation of reservoir outflow and the reference base flow was proposed. The results in this paper serve as a technical reference for studying changes in the hydrological regime and lessening their impacts on aquatic organisms in hydro-photovoltaic complementary development.