基于MIKE21的潖江蓄滞洪区洪水危险性快速预测

Flood hazard forecast of Pajiang River flood storage and detention basin based on MIKE21

潖江蓄滞洪区是广东省唯一的蓄滞洪区,对该蓄滞洪区蓄滞北江上游超标洪水时造成的洪水危险性进行快速、动态的量化估算,有助于对这一蓄滞洪区的防洪调度和防洪规划进行科学的指导。从这一角度出发,运用成熟的MIKE21平台搭建了潖江蓄滞洪区洪水演进数值模型,应用MIKE21 FLOW MODEL FM模块中的有限体积法计算了潖江蓄滞洪区的洪水水位、滞洪时间、蓄洪量、流速的动态变化。数值模拟结果表明:当北江流域遭遇100 a和300 a一遇洪水时,潖江蓄滞洪区蓄洪量分别为3.45×108m3和3.98×108m3,蓄洪量的大小依赖于通过江口墟水位站水位的高低;结合该蓄滞洪区电子地图,得到面临洪水危险性较大的地区是地势低平的源潭镇、飞来峡镇和龙潭镇;洪水淹没历时、到达时间因子是洪水主要危险性因素。潖江蓄滞洪区产生的洪水危险性与该蓄滞洪区有关规定非常一致,进一步表明,基于MIKE21模块可用于陆地水文学的数值模拟,据此可进行快速的洪水危险性预测。

Pajiang River flood storage and detention basin is the only flood storage and detention area in Guangdong Province, thus a rapid, dynamic and quantitative estimation for flood hazard when it stores excessive standard flood of Beijiang River upstream is helpful to the scientific instructions for flood control and planning. Viewing on this, this paper built a Pajiang River flood evolution numerical model on the mature platform MIKE21, calculated the dynamic changes of flood water level, time of storage and detention, flow, storage capacity of Pajiang River flood detention employing the finite volume method in MIKE21 FLOW MODEL FM module. Numerical simulation results show that, for floods with return periods of 100 a and 300 a, the flood volumes of Pajiang River storage and detention basin, are 3.45 × 10s m3 and 3.98 ×10s m3 respectively, depending on the water level of Jiangkouxu station; with the information from the electronic map, low and flat areas that face heavy flood danger are figured out as Yuantan Town, Feilaixia Town and Longtan Town; main flood risk factors are flood duration and arrival time. Numerical simulation results based on platform MIKE21 agree very well with the relevant provisions of Pajiang Riverflood storage and detention basin, which further proves that MIKE21 module can be employed in terrestrial hydrology simulation and predict quickly flood hazard.