黄河下游悬河段断流对沿岸地下水影响评价

Influences of the Yellow River Downstream Breaking on Groundwater Resources of the Watershed

黄河下游悬河段地下水系统分布面积29288·27km2,含有两个含水层组。浅层含水层组赋存潜水和微承压水,中深层含水层组赋存承压水;并对含水介质结构、边界条件及地下水流态进行了研究,建立了水文地质概念模型,构建了三维地下水流数学模型。通过对数学模型的识别和验证,进行了悬河段地表水、地下水转化关系的模拟研究;预测了黄河下游在不同的断流时间和断流河段长度下,黄河侧渗量的变化趋势。模拟计算结果表明,花园口站—河口段全年断流时,黄河悬河段无侧渗补给;断流300天时,黄河全年侧渗量为2·98×108m3,较现状年侧渗量减少了52·25%。夹河滩站—河口段全年断流时,黄河全年侧渗量为1·6×108m3,较现状年侧渗量减少了74·4%;断流300天时,黄河全年侧渗量3·46×108m3,较现状年黄河侧渗量减少了44·5%。泺口站—河口段全年断流时,黄河全年侧渗量为4·83×108m3,较现状年黄河侧渗量减少了22·58%;断流300天时,黄河全年侧渗量为5·17×108m3,较现状年黄河侧渗量减少17·06%。利津站—河口段全年断流时,黄河全年侧渗量为6·15×108m3,较现状年黄河侧渗量仅减少1·5%。上述研究为水资源合理开发利用和黄河水量人工实时调控提供了依据。

Groundwater resources plays an important role for the areas of the Yellow River downstream, and the lateral seepage of surface water is an important source for groundwater recharge of the watershed. Groundwater system in the Yellow River downstream has a total area of 29288.27km^2, and consists of two aquifer systems：shallow aquifer system （the groundwater type is phreatic water and micro-confined water） and middle-deep aquifer system （the groundwater type is confined water）. Based on aquifer characteristics, boundary condition and groundwater flow regime, the hydro geologic concept model and the three-dimensional groundwater flow simulation mathematical model was built. The mathematical model was solved, calibrated and validation with Feflow （Finite Element subsurface FLOW system） software. According to validated numerical model, the paper simulated the relationship between surface water and subsurface water, and forecasted the trend of seepage quantity of groundwater from the Yellow River under different conditions including different breaking periods at time and length. The simulated result showed that, when the breaking length is from Huayuankou station to the river entrance, there was no lateral recharge of surface water to groundwater when the breaking occtLrred throughout the year, and the lateral recharge quantity is 2.98 × 10^8m^3 which is about 52.25% of the amount in a normal case when the breaking time is 300 days. When the breaking length was from Jiahetan station to the river entrance and the breaking happened in a year, the lateral seepage quantity of the Yellow River is 1.6 × 10^8m^3 , which is about 74.4% less than the current year. When the breaking time is 300 days, the relevant seepage quantity is 3.46 × 10^8 m^3 , which is about 44.5 % less than the current year. When the breaking length was from Lekou station to the river entrance and the breaking existed in the whole year, the lateral seepage quantity of the Yellow River is 4.83 × 10^8m^3 , which is about 22.58 % less than the current year;when the breaking time is 300 days,the relevant seepage quantity is 5.17 × 10^8m^3 , which is about 17.06% less than the current year. When the breaking length was from Lijin station to the river entrance and the breaking time is throughout the year, the lateral seepage quantity of the Yellow River is 6.15 × 10^8m^3, which is about 1.5% less than the current year. The above results provide the references for utilization and regulation of the Yellow River water and groundwater of the watershed.