北京市“23·7”特大暴雨对平谷区地下水动态的影响

Influence of"23·7"extraordinary rainstorm on groundwater dynamics in Pinggu District in Beijing

为研究“23·7”特大暴雨对北京平谷区地下水动态的影响,及不同区域的地下水补给规律,基于地下水位和降雨数据,分析降雨前后平谷平原区地下水位的时空变化情况。结果表明:从2010年开始,平谷平原区年际地下水位呈波动回升趋势,年内地下水位呈先减少后回升的变化规律,汛期降雨对地下水补给有至关重要的作用。7月28日到8月2日强降雨期间,平谷区地下水得到了较大补给,截至8月16日,平谷区地下水位相较降雨前,回升了1.88 m。受山区侧向补给作用影响,平谷平原区地下水位在未来一段时间还会保持持续回升趋势,预计最终会在年末回升到峰值。本次降雨过程中,平谷平原区西北部地下水对降水响应更加敏感,与西北部相比,平谷平原区东部地下水对降水的响应存在2~3 d的滞后。本研究为探究平谷区降水与地下水的关系提供参考,为平谷区地下水储备建设提供支撑。

In order to study the impact of extraordinary rainstorm(23·7)on the groundwater dynamic in Pinggu District of Beijing and the groundwater recharge law in different regions,this paper analyzes the spatio-temporal changes of groundwater level in Pinggu Plain before and after the rainfall based on the groundwater level and rainfall data.The results indicate that the interannual groundwater level in Pinggu Plain has a fluctuating upward trend since 2010,and the variation of groundwater level during a year is decreasing in the first half of a year and increasing in the second half.The flood season rainfall has a vital role in groundwater recharge.During the heavy rainfall from July 28 to August 2,the groundwater in Pinggu District has been greatly replenished.By August 16,the groundwater level in Pinggu District has risen by 1.88m compared with before the rainstorm.Affected by the lateral recharge effect of the mountain,the groundwater level in Pinggu Plain will maintain a continuous rising trend in the future,and it is expected to reach the peak at the end of the year.During the rainfall,the groundwater in the northwest of Pinggu Plain has a faster response to the precipitation.Compared with the northwest,the groundwater in the eastern Pinggu Plain has a lag of 2-3 days to the precipitation response.This study provides a reference for exploring the relationship between precipitation and groundwater in Pinggu District,and supports for the construction of groundwater reserves in Pinggu District.