黄河小浪底水库拦沙后期运用方式的思考与建议

Ponderations and suggestions on operation mode of Xiaolangdi Reservoir in its second stage of sediment retaining

小浪底水库于1999年10月下旬下闸蓄水,2007年起进入拦沙后期。水库的运用方式,对于延长水库寿命,确保黄河下游防洪减淤,至关重要。本文基于三门峡水库数十年的运用经验,指出"拦粗排细"只有在水库淤积状态下出现,水库冲刷则可能出现"拦细排粗"或"粗细俱下、粗沙略多"的情况,评述了拟定的小浪底水库拦沙后期的运用方式,提出了水库运用应从"拦沙减淤"向"调沙减淤"转变的水库合理运用的基本原则和调整黄河中游大型水库的目的任务以确保黄河下游长治久安的建议。

The Xiaolangdi Reservoir is a large hydro-project on the Middle Yellow River with a total capac- ity of 12.65 billion m3 and the main tasks of flood control and sediment mitigation of the Lower Yellow River. Now, the reservoir is being operated in its second stage of sediment retaining. According to the planned scheme, the Xiaolangdi Reservoir will be operated in the form of so called ＂overyear regulation of sediment and indeterminate scouring of the reservoir＂ with the aim to prolong the life span of the reservoir. However, according to the experience from the Sanmenxia Reservoir, another major reservoir upstream of the Xiaolangdi, when the water level is dropped until the reservoir is empty, the strong retrogressive erosion would happen, and large amount of the eroded particles companied by the sediment from its upstream watershed would sluice and cause the tremendous siltation in the Lower Yellow River. Also from the San- menxia experience, a new operation mode including storing the fresh water in the nonilood season and sluic- ing the muddy water in the flood season, i.e., the mode of ＂water-sediment regulation＂ is suggested. The new mode could be of benefit to decrease the deposition both in the reservoir and the Lower Yellow River, and might be the only way for the operation mode of the Xiaolangdi Reservoir in its second operation stage. Furthermore, some other suggestions of deposition mitigation both in the reservoir and the Lower Yel- low River in the long time period on further are also submitted in this paper.