The optimization of flow conditions in the spawning grounds of the
Chinese sturgeon (Acipenser sinensis) through Gezhouba Dam units
Abstract
The waters downstream from the Gezhouba Dam are the only spawning
grounds of the Chinese sturgeon. To optimize the flow conditions in the
spawning grounds by controlling the opening mode of the Gezhouba Dam
generator units, a mathematical model of the three-dimensional
hydrodynamics of the Chinese sturgeon spawning grounds was established
in FLOW-3D. The model was verified with velocity measurements, and the
results were in good agreement. Additionally, the model was used to
invert the flow field of monitoring results from 2016-2019, and it was
concluded that the preferred velocity range for the Chinese sturgeon was
0.6-1.5 m/s. The flow fields of different opening modes of the generator
units were simulated with the same flow rate, and the results showed
that the suitable velocity area was the largest when all units of the
Dajiang Plant of the Gezhouba Dam were open and that conditions were
especially favourable on the left side. Comparison of the suitable
velocity area with different flow rates showed that when the flow rate
was less than 12000 m3/s, more than 90% of the area
was suitable and that when the flow rate was greater than 12000
m3/s, the suitable area decreased rapidly with
increasing flow rate. Moreover, the suitable areas under different
opening modes under high-flow conditions were compared, and the results
showed that at flow rates of 12000 ~ 15000
m3/s, opening 11~13 units on the left
side was best. When the flow rate reached 15000 m3/s,
it was best to open all of the units. In this paper, the optimal opening
scheme at different flow rates was analysed, and the results provide new
ideas for Chinese sturgeon protection and ecosystem protection.