洞庭湖蓄洪能力具有重要的意义。首先，洞庭湖是湘、资、沅、澧四水洪峰的汇流中心，它的蓄洪能力直接关系到缓和洞庭湖自身流域的洪峰压力。其次，作为长江的支流湖，洞庭湖的蓄洪能力也间接关系到长江流域的蓄水系数，从而关系到缓和长江下游的洪水水位。在洞庭湖现有泄流系数不变的情况下，要增加洞庭湖的蓄洪能力，主要靠扩大蓄洪区和加高堤垸防洪高度。由于这两者都存在天然限制，所以不可偏废，只可兼顾。 Dongting Lake flood storage capacity is of great significance. First of all, Dongting Lake is the confluence center of Hunan, Ziyuan, Yuan and Yishu floodplains. Its flood storage capacity is directly related to easing the peak pressure of Dongting Lake itself. Secondly, as a tributary lake of the Yangtze River, the storage capacity of Dongting Lake also indirectly relates to the water storage coefficient in the Yangtze River Basin, thus affecting the flood level in the lower reaches of the Yangtze River. In the case of the existing discharge coefficient of Dongting Lake remains unchanged, it is necessary to increase the flood storage capacity of Dongting Lake, mainly by expanding flood control areas and raising the height of embankments for flood control. Due to the natural limitations of both, we can not afford to give up.