平原地区城市湖泊防洪与景观功能协调研究——以枝江市金湖为例

Study on coordination between flood control and landscape function of urban lake in plain area——A case of Jinhu Lake in Zhijiang City

为了使城市湖泊尽可能滞蓄雨洪、发挥景观功能、打造良好的居民"亲水空间",以枝江市金湖为例,根据金湖主要泄洪渠道的实际情况,利用Mike 21模型模拟计算汛限水位值,按照景观水位确定大、小洪水工况下合理的水位。在此基础上,提出传统的静态景观水位与改进的动态景观水位两种方案。结果表明:以50年一遇、30年一遇为代表的大洪水工况下合理景观水位为40.7 m,以20年一遇、10年一遇为代表的小洪水工况合理景观水位为41.3 m;静态方案采用50年一遇洪水计算结果为标准执行,将40.7 m作为金湖固定的景观水位;动态方案水位可在41.3~40.7 m之间波动;金湖适宜采用动态景观水位运行方案,水位可在40.7~41.3 m之间波动;根据短期预报及历史监测资料分析后合理调度,将41.3 m作为金湖常水位,确定预测洪水大小后调整水位迎战洪水。据此,可在充分利用水资源的同时有效协调景观高水位需求与防洪之间的矛盾。

In order to retain and store rainfall flood water in urban lake as much as possible and exert its landscape function for building better wateraccessiblespace for resident,Jinhu Lake in Zhijiang City is taken as the study case,and then the reasonable water levels under large and small flood conditions are determined in the light of the landscape water levels therein by means of simulatively calculating the flood control limited water level with Mike 21 in accordance with the actual statuses of the main flood discharge channels of Jinhu Lake,On the basis of this,two alternatives,i. e. conventional static landscape water level and improved dynamic landscape water level,are proposed herein. The result shows that the reasonable landscape water level under the conditions of the large floods represented by the returning periods of 50 years and 30 years is 40. 7 m,while the reasonable landscape water level under the conditions of small floods represented by the returning periods of 20 years and 10 years is 42. 3 m. The calculated result of the flood with the returning period of 50 years is taken as the standard for the static alternative,for which40. 7 m is taken as the fixed landscape water level for Jinhu Lake. The water level for the dynamic alternative can be fluctuated between 41. 3 - 40. 7 m. The dynamic landscape water level operation alternative is suitable for Jinhu Lake,for which the water level can be fluctuated between 40. 7 - 41. 3 m. In accordance with the reasonable dispatching after the analysis on the short-term forecast and historical monitoring data,41. 3 m is taken as the normal water level for Jinhu Lake,which can be adjusted to face and fight with flood after determining and predicting the relevant floodintensity. Accordingly,the contradiction between high water level demand for landscape and flood control can be effectively coordinated at the same time of full utilization of water resources.