会仙湿地岩溶地下水数值模拟

以会仙岩溶湿地的核心区域为研究对象, 基于研究区的地质条件和水文地质条件, 概化出水文地质概念模型, 运用 Visual MODFLOW 软件对会仙湿地地下水的分布特征进行数值模拟, 经模型识别与验证, 其模拟水位与观测水位取得较好的拟合效果。结果表明: 研究区地下水总体呈自北向南递减趋势流动, 北部补给区地下水位最高, 西南部排泄区地下水位最低, 南北地下水位平均差值为 7.34 m; 水位动态变化受降雨强度影响较大, 呈现出明显的季节性变化规律; 南部分水塘、睦洞湖等排泄带水源补给充足, 地下水位变幅不超过 1 m, 北部补给区的水位变幅在 3 m 以上; 经水均衡计算, 模拟期的地下水总补给量为 44 272. 92 万 m3 / a, 其中降雨入渗补给量占 76.85% , 地下水的总排泄量为 42 723. 06 万 m3 / a, 地下水开采量与蒸发量分别占 33. 86% 、36. 63% ; 研究区在模拟期内总体处于正均衡状态, 但处于负均衡的枯水月份占到 2/ 3, 湿地的退化直接影响其防洪调蓄和保水、蓄水能力, 使“ 旱期过旱、涝期过涝” 现象极为显著。

Numerical simulation of karst groundwater in Huixian wetland

The core area of Huixian karst wetland is selected as the research object. Based on the geological and hydro geological conditions of the research area, the concept model of hydrogeology is generalized. Using Visual MODFLOW software, the distribution characteristics of groundwater in the Huixian wetland are simulated. The model identification, and verification showed that the simulated water level and the observed water level achieved a good fitting effect. Based on the simulation results, the dynamic change of groundwater in the research area is analyzed, and the water balance in each simulation period is calculated. The results show that: the g roundwater in the study area is generally decreasing from north to south, the groundwater level in the northern recharge area is highest, the groundwater level in the southwest drainage area is the lowest, and the average difference between the north and the south groundwater level is 7.34 m, respectively; the dynamic change of water level is greatly affected by rainfall intensity , showing obvious seasonal change rule; in the southern part of the pond, Mudong lake, and other drainage zones, the water supply is sufficient , and the underg ro und water is under control; the variation range of water level is not more than 1 m, and the variation range of water level in the northern recharge area is more than 3 m, the total recharge amount of groundwater in the simulation period is 442. 729 2 million m3 / a, after water balance calculation, of which the rainfall infiltration.recharge accounts for 76.85% , the total discharge of gro undw ater is 427.306 million m3 / a, and the exploitation and evaporation of groundwater account for 33.86% and 36.63% respectively ; the study area is generally in a positive equilibrium state in the simulation period, and the degradation of wetland directly affects flood control, storage capacity , water conservation, and water storage capacity , which refelcts the phenomenon of " excessive drought in drought periods and excessive waterlogging during floods" .