Optimization of the flow conditions in the spawning ground of the Chinese sturgeon (Acipenser sinensis) through Gezhouba Dam generating units

Chinese sturgeon (Acipenser sinensis) is a critically endangered species, and waters downstream from Gezhouba Dam are the only known spawning ground. To optimize the velocity conditions in the spawning ground by controlling the opening mode of Gezhouba Dam generator units, a mathematical model of Chinese sturgeon spawning ground was established in FLOW-3D. The model was evaluated with velocity measurements, and the results were determined to be in good agreement. By inverting the 2016–2019 field monitoring results, the model shows that the preferred velocity range for Chinese sturgeon spawning is 0.6–1.5 m/s. Velocity fields of different opening modes of the generator units were simulated with identical discharge. The suitable-velocity area was maximal when all units of Dajiang Plant of Gezhouba Dam were open. For discharges below 12,000 m3/s, most of the area was suitable; for discharges above 12,000 m3/s, the suitable area rapidly decreased with increasing discharge. A comparison of suitable areas under high-flow showed that at discharges of 12,000–15,000 m3/s, opening 11–13 units on the left side was optimal. For discharges above 15,000 m3/s, all units should be open. We used these results to recommend a new operation scheme to support the conservation of Chinese sturgeon.

Optimization of the Flow Conditions in the Spawning Grounds of the Chinese Sturgeon (Acipenser Sinensis) Through Gezhouba Dam Generating Units

Chinese sturgeon (Acipenser sinensis) is a critically endangered species, and waters downstream from Gezhouba Dam are the only known spawning grounds. To optimize the velocity conditions in the spawning grounds by controlling the opening mode of Gezhouba Dam generator units, a mathematical model of Chinese sturgeon spawning grounds was established in FLOW-3D. The model was evaluated with velocity measurements, and the results was determined to be in good agreement. By inverting the 2016-2019 field monitoring results, the model shows that the preferred velocity range for Chinese sturgeon spawning is 0.6-1.5 m/s. Velocity fields of different opening modes of the generator units were simulated with identical discharge. The suitable-velocity area was maximal when all units of Dajiang Plant of Gezhouba Dam were open. For discharges below 12000 m3/s, most of the area was suitable; for discharges above 12000 m3/s, the suitable area rapidly decreased with increasing discharge. A comparison of suitable areas under high-flow showed that at discharges of 12000~15000 m3/s, opening 11~13 units on the left side was optimal. For discharges above 15000 m3/s, all units should be open. We used these results to recommend a new operation scheme to support the conservation of Chinese sturgeon.

Impacts of River Engineering on Multi-Decadal Water Discharge of the Mega-Changjiang River

Knowledge of river engineering impacts on water discharge is significant to flow guidelines and sustainable water resource managements for balancing human consumption and the natural environment. In this study, based on the collected multi-decadal discharge data at Yichang, Hankou, and Datong stations, we determined that in October, Three Gorges Dam contributed 34.4%, 24.5%, and 18.7% to the discharge decrease in the upper, middle, and lower reach, respectively, while Gezhouba Dam contributed 14.5%, 10.7%, and 10%. Danjiangkou Reservoir caused the discharge ratio of Hanjiang to Changjiang to decline from 7.2% during 1954–1973 to 6.3% during 1973–2014. Owing to growing water withdrawal and consumption, we suggest that the distribution of water diversion and consumption should be regulated to prevent the probable occurrence of the severe issue of salt water intrusion in the Changjiang Estuary in 2028.

Study on the Evaluation Scheme of Emergency Response Capacity of The Three Gorges - Gezhouba Dam

according to different navigation condition and environment of traffic emergency strategy, using fuzzy algorithm to the actual situation of ship parameters of the actual situation assessment, the result will be according to the instruction from the data graph for the actual operation, effectively avoid risk. Ships that should be properly arranged in a non-emergency session should avoid the concentration of traffic in heavy traffic and cause unnecessary security risks. The general function of ship safety is established by mathematical modeling, and the application function is used to control the ship. Ensure safe navigation.

Spatiotemporal Distribution and Assemblages of Fishes below the Lowermost Dam in Protected Reach in the Yangtze River Main Stream: Implications for River Management

Now more and more ecologists concern about the impacts of dam construction on fish. However, studies of fishes downstream Gezhouba Dam were rarely reported except Chinese sturgeon (Acipenser sinensisGray). In this study, catch investigations and five hydroacoustic detections were completed from 2015 to 2016 to understand the distribution, size, and categories of fishes and their relationship with the environmental factors below Gezhouba Dam in protected reach in the Yangtze River main stream. Results showed significant differences in fish distribution and TS (target strength) between wet and flood seasons. Mean TS in five hydroacoustic detections were −59.98 dB, −54.70 dB, −56.16 dB, −57.90 dB, and −59.17 dB, respectively, and dominant fish species areCoreius guichenoti(Bleeker),Siniperca chuatsi(Basilewsky), andPelteobagrus vachelli(Richardson). In the longitudinal direction, fish preferred to stay in some specific sections like reaches 2, 4, 7, 8, 11, and 16. Since hydrology factors change greatly in different seasons, environmental characteristics vary along the reaches, and human activities play an important role in the fish behavior, it is concluded that great cross-season changes in hydrology lead to the differences in TS and fish assemblages and that geography characteristics, especially channel geography, together with human activities influence fish longitudinal distribution. This finding provides basic knowledge of spatiotemporal distribution and assemblages of fishes in the extended reaches downstream Gezhouba Dam. In addition, it offers implications for river management. It could also serve as reference of future research on fish habitat.