An Adaptive Control Method Of Reservoir Operation In Sediment-laden Rivers And Its Application

Sediment-laden rivers are generally characterized by less runoff and high sediment supply, concentrated water discharge, transversal section with main channel and floodplain, etc. So, reservoirs built on these rivers are required to not only well display their benefits but also appropriately deal with the sediment accumulation problems, whose operations are more complex than those on low sediment concentration rivers. It is significant to identify an appropriate operation method for the reservoirs on high sediment concentrated rivers.By introducing the adaptive control theory, the concept of adaptive operation of reservoir is proposed, and the corresponding adaptive operation model is constructed. Based on the constructed water and sediment mathematic models, the adaptive operation model can identify the real-time state of the reservoir and construct the adaptive controller considering the reservoir's water supply, flood protection, electric power generation and other benefits under the concerned state, and adjust the water level and discharge in real time according to the incoming water and sediment conditions, which can make the reservoir operation be in a optimized state all the while.In the adaptive operation model, stochastic hydrology data are created by time series method, which are used to identify the happening probabilities of floods with different discharge under different conditions. And the operation program is adjusted according to the probabilities, which reflecting the model's adaptability to the changing water and sediment conditions. Besides, several processing methods are used in the model, including: fuzzy sets are used to classify the flood season into prophase, main phase and anaphase; fuzzy cluster is used to analyze the incoming water and sediment magnitude; multi-objective optimization is used to initially identify the critical ungated flow and sediment content; the method of gradually raising normal pool level is used to decrease sediment accumulation; and the residual storage capacities of the reservoir in different periods of time are referenced to adjust the critical ungated flow and sediment content in real time. By synthetically using these methods, the difficulties occurring in the application of the model are overcome, and the efficiency and operability of the model are greatly improved.The adaptive operation model is individually applied to single operation of Tingkou reservoir on Heihe River in Shaanxi province and multiple reservoirs operation. The application results indicate that the adaptive operation model can well respond to the changing water and sediment conditions, its parameters can be adjusted in real time with the changes of the input variables, and the reservoir can supply abundant water with a large residual capacity conserved. Through comparing with the conventional multi-objective optimization method of reservoir operation, the adaptive model is found to supply more water with a larger residual capacity, and obviously be superior to the conventional method. The results and analysis prove the rationality of the adaptive operation and the feasibility and validity of the adaptive operation model.Furthermore, the water and sediment characteristics of high sediment concentrated rivers are analyzed, and the describing approaches about the momentum correction coefficient and transverse velocity distribution for the rivers are proposed. Then the water and sediment mathematic models for high sediment concentrated rivers are constructed, which provides good supports for the studies on the operation model of reservoirs on sediment-laden rivers.