白洋淀湖岸带地表水与地下水垂向交换研究

A study of vertical exchange between surface water and groundwater around the banks of Baiyangdian Lake

地表水与地下水相互转化关系一直是水文地质研究的热点问题。以往研究更多关注河流的河岸带,但对于相对静止水体—湖泊的湖岸带研究相对偏少。选择白洋淀湖岸带作为研究对象,在周边湖岸带系统部署水位、水温监测系统,采用温度示踪法,开展白洋淀湖岸带区域的地表水与地下水垂向交换量化研究。同时,结合达西定律,间接反演获取垂向渗透系数,系统总结出一套联合利用温度示踪法和达西定律定量研究湿地垂向水交换的方法。结果表明,白洋淀湖岸带以地表水渗漏补给地下水为主,其垂向交换流速可达0.2~1.1 cm/d,沉积岩性主要为粉质黏土、粉土及粉细砂,垂向渗透系数为0.038~0.912 m/d。研究结果可为制定白洋淀湿地补水方案和生态环境保护措施提供基础数据支撑。

Interaction between surface water and groundwater has always been a hot topic in hydrogeological researches.Previous studies focused on the hyporheic zone of rivers,but the hypolentic zone of lakes with relatively static water bodies was seldom examined.The Baiyangdian Wetlands is taken as a pilot area in this study,and a monitoring system of water table and temperature is set up.The vertical interaction fluxes between surface water and groundwater is quantified by using a heat tracing method.According to the Darcy’s Law,the vertical coefficient of permeability is calculated inversely.Based on the heat tracing method and the Darcy’s Law,a way of quantifying vertical interaction between surface water and groundwater is summarized.The results show that infiltration from surface water to groundwater around the banks of the Baiyangdian Wetlands is dominant in the interaction procedure.The total infiltration velocity from surface water to groundwater during the monitoring period ranges from 0.2 to 1.1 cm/d,and the vertical hydraulic conductivity,from 0.038 to 0.912 m/d.The conclusions in this paper can provide data support for strategy of water diversion and protection of ecoenvironment in the Baiyangdian Wetlands.