沙量平衡法计算冲淤量的不确定度：—兰州至花园口河段

本文主要讨论内容有三：一是研究分析兰州以下无实测冲淤变化资料河段的主河槽冲淤厚度，二是对有实测断面法冲淤量河段，可用沙量平衡方程计算综合误差值，中用沙量平衡计算的冲淤量实际上包括了综合误差，三是用无产测冲淤变化资料河段，本文用同流量水位法和沙量平衡法估算兰州以下各个河段的冲淤厚度。还引用不同研究答员用沙量的平衡法计算的头道拐－龙门河段1959－1989年冲淤量，说明其沙量平衡法的冲淤量涌反映实际的河道冲淤情况。

Uncertainties of Amount of Sedimentation Evaluated by Sediment Balance Equation __for Yellow River Reaches between Lanzhou and Huayuankou

The following three aspects were discussed in this paper: 1.The equivalent thickness of the amount of deposition or erosion in the main channel was analyzed for reaches below Lanzhou where no sedimentation survey data are available; 2. For reaches where amount of deposition or erosion can be obtained directly from systematic sedimentation survey data, sediment balance equation can be used to evaluate the composite error. The amount of deposition or erosion would involve largely the composite error if it were estimated by means of the sediment balance equation. 3. For reaches where no surveying data are available, thickness of the amount of deposition or erosion is estimated by sediment balance equation and also by the variation of water level under same discharge. Comparisons were made with the amount of deposition or erosion computed by different people for periods from 1959 to 1989 in different research projects. It is concluded that the amount of sedimentation obtained by means of the sediment balance equation can not reflect the actual status of river sedimentation.