Dynamic control of flood-limited water level (FLWL) is an effective method to realize floodwater utilization, which can alleviate the contradiction between flood control and conservation during flood seasons. In this study, a method of identifying upper bound of FLWL is presented simultaneously considering pre-release for water supply in rainless period and pre-release for flood control in the early period of flood. A risk analysis framework considering continuous rainless-day forecast error and flood forecast error is established. An improved truncated Gaussian distribution to describe rainless-day forecast error is proposed, combined with normal distribution describing flood forecast error to derive the distribution of excess storage determined by the method of pre-release based on forecasts. Then risk assessment and decision making are conducted. The Xianghongdian Reservoir is selected for a case study. The results indicate that the allowable excess storage can be determined under a given acceptable risk by using this analytical method. Moreover, the excess storage decreases with the safety margin reserved for the downstream increasing under the same acceptable risk.

动态控制汛限水位（FLWL）是实现洪水利用的有效方法，可以减轻汛期汛期防洪与保育之间的矛盾。在这项研究中，同时提出了一种确定FLWL上限的方法，该方法同时考虑了无雨期的供水预泄和洪水初期的防洪预泄。建立了考虑连续无雨日预报误差和洪水预报误差的风险分析框架。提出了一种改进的截断高斯分布描述雨天预报误差，并结合描述洪水预报误差的正态分布推导了基于预报的预发布方法确定的超额存储量分布。然后进行风险评估和决策。选择了香洪甸水库进行案例研究。结果表明，通过使用这种分析方法，可以在给定的可接受风险下确定允许的过量存储量。此外，在相同的可接受风险下，多余的存储量会随着为下游保留的安全裕度的增加而减少。