How a reservoir can be used for long-term and not abandoned by sediment deposition

What is it about?

The long-term utilization of reservoirs is a disruptive concept in reservoir planning and design. It was conventionally believed that a large multi-purpose reservoir would eventually be abandoned due to sediment deposition caused by the long-term elevation of water levels. The concept of reservoir life was introduced based on this convention. The “long-term utilization of reservoirs” was first proposed by some Chinese researchers, i.e. reduce the water level in flood season (except for the duration of retarding floods) for sediment discharge, and raising the water level in the other period for reservoir utilization. The operation strategy has been successfully applied to some large and mid-sized reservoirs in China. The author has studied the mechanism of long-term utilization of reservoirs based on the general law of reservoir sedimentation, provided the quantitative relation between the conservation effective storage and the sediment discharge period and control water level. He developed a simplified mathematical model for planning the operation strategy, sediment discharge period, and control water level for the long-term utilization of reservoirs. Canadian International Project Management (CYJV 1984) commented on this long-term operation plan: “It is important to point out that the theory of equilibrium slope and of preserving the long-term storage of reservoirs, upon which the entire sediment management strategy of the Three Gorges Projects is based, is developed in China to a fine art. No other nation in the world has much experience in designing reservoirs so that their function in regulating and flood control storage can be preserved indefinitely.”

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Why is it important?

The abounded reservoir by sediment deposition causes huge economic losses and negative environment impact. Thus the planning operation strategy for long term operation has great significance. The research results lay the theoretical foundation for the operation strategy of long-term utilized reservoirs. It has not only explained why a reservoir can be designed and operated to conserve its effective storage for long-term, but it has also described the design approach of a long-term utilized .reservoir. The simplified mathematical model developed by the author will help experts plan and design a long-term utilized reservoir.