河北平原典型小流域降雨入渗补给规律研究

Study on the law of rainfall infiltration and recharge in a typical watershed of Hebei Plain

准确计算降雨入渗补给量是评价平原区地下水资源量的基础,传统的年补给系数法未考虑降雨特征、土壤墒情等因素影响,导致评价结果精度不高。本研究以河北平原下博和沧县运西两个典型小流域为例,采用动态分析法研究次降雨的入渗补给过程。结果显示以7 d为时间间隔适合作为划分次降雨的标准,次降雨量加土壤含水量(P+SW)与降雨入渗补给量(Pr)相关性最好,优于次降雨量(P)和次降雨量加前期雨量(P+Pa);动态分析法计算的降雨入渗补给量较传统降雨入渗系数法,精度提高22%~40%,且年补给系数法高估了河北平原区的年地下水补给量。本研究为河北中东部平原准确评价降雨入渗补给量提供了技术参考,对支撑区域的地下水合理开发利用及地下水超采综合治理具有较强的科学和实践意义。

Accurate calculation of rainfall infiltration recharge is the basis of the evaluation of groundwater resources in plain areas.The traditional annual recharge coefficient method does not consider the influence of rainfall characteristics, soil moisture and other factors, which leads to low accuracy of the evaluation results.In this study, two typical watersheds in Xiabo and Yunxi of Cangxian County in Hebei Plain were taken as examples to study the infiltration and recharge process of secondary rainfall by dynamic analysis.The results show that the interval of 7 days is suitable for the time standard of secondary rainfall.The correlation between secondary rainfall plus soil water content(P+SW) and rainfall infiltration recharge(Pr) is the best, which is better than that of secondary rainfall(P) and secondary rainfall plus early rainfall(P+Pa).The accuracy of rainfall infiltration recharge calculated by dynamic analysis method is 22~40% higher than that of traditional rainfall infiltration coefficient method, and the traditional annual recharge coefficient method overestimates the annual groundwater recharge in Hebei plain area.This study provides a method reference for the accurate evaluation of rainfall infiltration recharge in the central and eastern plain of Hebei Province, and has strong scientific and practical significance for the rational exploitation and utilization of groundwater in the support area and the comprehensive treatment of groundwater overexploitation.