现代黄河三角洲上部冲积平原降水入渗补给量研究

Study on Recharge of Precipitation Infiltration in the Upper Alluvial Plain of the Modern Yellow River Delta

大气降水是黄河三角洲地区浅层地下水的主要补给来源。确定降水入渗补给量是地下水资源可持续利用的基础。论文选择现代黄河三角洲上部冲积平原的典型地貌单元安装自记水位计,获得了2004年30 min一次的浅层地下水水位动态数据。结合日降水量资料,应用地下水位动态法,在Matlab中编程计算了2004年次降水入渗补给系数和年平均降水入渗补给系数,探讨了该系数时空变化的特点和主要影响因素,估算了降水补给浅层地下水的水量。主要结论如下:①研究区域内浅层地下水埋深主要在2 m以内变动,属于浅埋类型。②降雨特征决定了该区域次降水入渗补给系数的大小,地表渗透性决定该区域次降水入渗补给系数的时空变异。次降水入渗补给系数随着雨前地下水埋深的增加显示出增大的趋势。③研究区域平均年降水入渗补给系数为0.186。2004年降水补给浅层地下水总量为7.4×108m3,占当年黄河径流量的3.7%。

In the Modern Yellow River Delta, the runoff of the Yellow River decreased year by year, as a resuh of increased irrigation in the upper reaches area. The recharge of precipitation infiltration became the main fresh water source of shallow aquifer in the Modern Yellow River Delta. Accurate evaluation of the recharge of precipitation infiltration is the precondition to exploit groundwater rationally. Based on data loggers installed in boreholes of typical topographic areas in the Modern Yellow River Delta, groundwater table depth was read every thirty minutes. Combined with daily rainfall of 2004, the feed coefficients of precipitation infiltration were calculated by Matlab programming and the temporal and spatial varieties were analyzed to make the main factors clear. It is concluded that ： 1 ） groundwater table depth changed mainly within 2 m below surface ; 2） the features of rains and penetrability of land surface were the most important aspects decided the value and the temporal and spatial varieties of the feed coefficients of precipitation infiltration that increase with enlarging of groundwater table depth ; 3） the annual feed coefficient of precipitation infiltration was 0. 186. The groundwater recharge from precipitation is up to 7.4 ×10^8m^3 accounted for 3.7 % of the runoff of the Yellow River Delta in 2004.