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分析认为 ,小浪底水库逐步抬高主汛期水位拦沙和调水调沙运用 ,库区为锥体淤积 ,由下而上、由低而高逐步淤积 ,比降变小 ,主汛期运用水位 2 5 4m ,形成高滩高槽形态 ,不影响三门峡坝下水位 ;支流拦沙库容充分淤积 ,拦沙库容约80亿m3。若水库一次抬高水位或主汛期高水位蓄水拦沙 ,水库为三角洲和带状淤积 ,在淤积向坝前推进过程中 ,洲面淤高 ,淤积上延 ,河床比降增大。为了不影响三门峡坝下水位 ,主汛期运用水位要降至 2 40～ 2 46m ,干流拦沙库容减少 15～ 2 5亿m3,支流河口拦门沙坎高 ,支流淤积面低 ,大量损失拦沙库容 ,因此应予避免。水库拦沙后 ,逐步降低主汛期水位至 2 30m ,形成高滩深槽的平衡形态 ,平均河床比降 3 .3 ,不影响三门峡坝下水位。小浪底水库选择最高水位 2 75m ,主汛期限制水位 2 5 4m ,死水位 2 30m ,总库容 12 6 .5亿m3,有效库容 5 1亿m3,其滩库容 41亿m3,槽库容 10亿m3,拦沙容积初期 80亿m3、后期 72 .5亿m3,下游平均减淤 78.7亿t
According to the analysis, the Xiaolangdi Reservoir gradually raised the water level for sand blockage and water and sediment adjustment in the main flood season. The reservoir area was conical siltation, which was from bottom to top, silted gradually from low to high, and the specific gravity decreased. In the main flood season, water level 25 4m, forming a high trough high trough morphology, does not affect Sanmenxia dam water level; tributary sediment storage capacity of silt, sediment storage capacity of about 8 billion m3. If the reservoir raises the water level once or the high water level in the main flood season stores water and sediment, the reservoir is deltaic and belt-shaped siltation. During the process of siltation to the dam, the silt surface will be silted up and deposition will be delayed and the river bed ratio will increase. In order not to affect the water level of Sanmenxia Dam, the water level in the main flood season should be reduced to 240 ~ 246m, and the trunk sediment storage capacity should be reduced by 150-250m m3. The tributary estuary blocked the sand high and the tributary silt surface low, The storage capacity should therefore be avoided. After the reservoir stopped sediment, the water level in the main flood season was gradually reduced to 230 m, forming a balanced pattern of high trough deep grooves with an average river bed ratio of 3.3, without affecting the water level at Sanmenxia Dam. The Xiaolangdi Reservoir has a maximum water level of 2 75 m, a main water level of 24 54 m, a dead water level of 30 m, a total capacity of 12.65 billion m3, an effective storage capacity of 501 million m3, a beach storage capacity of 4.1 billion m3 and a tank capacity of 1 billion m3. The volume of sediment blocking was 8 billion m3 in initial stage, 7.25 billion m3 in the latter period, and 7.87 billion t in the downstream