水位变化影响下的河水-地下水侧向交互带地球化学动态  

Influence of water level change on the geochemical dynamics of the lateral hyporheic zone between river water and groundwater

作　　者：杨平恒[1,2] 张宇[1,2] 王建力[1,2] 谢世友[1,2] 

机构地区：[1]西南大学地理科学学院岩溶环境重庆市重点实验室,重庆400715 [2]国土资源部岩溶生态环境重庆南川野外基地,重庆408435

出　　处：《水科学进展》2017年第2期293-301,共9页Advances in Water Science

基　　金：中央高校基本科研业务费专项资助项目(XDJK2014A016);重庆市研究生科研创新项目(CYS16050)~~

摘　　要：为了解不同水位变化影响下的河水与地下水侧向交互带地球化学特征动态,以重庆市马鞍溪为研究对象,选取丰水期向枯水期过渡的10—12月为研究期,对河水、地下水及交互带的水位、水温、溶解氧(DO)、pH值、电导率(EC)进行监测,结合对水体主要离子浓度的分析。结果表明,随枯水期到来,侧向交互带水位发生较大变化,交互带与河水间的水位梯度缩小,河水入渗动力逐渐减弱。水位的变化及入渗水温的降低,使交互带微生物活动减弱,pH值上升且变幅减小,DO上升。在其影响下,交互带EC下降,变幅减小,交互带对NO_3^-、SO_4^(2-)的净化能力降低,对Mn、Zn等重金属固定能力增强。通过分析交互带地球化学特征的变化,可推断出随马鞍溪枯水期的到来,侧向交互带边界由距河岸30~50 cm移动至距河岸30 cm以内。Water level of the hyporheic zone essentially varies in different hydrological periods. In order to investigate the geochemical characteristics of the lateral hyporheic zone in different hydrological periods, Maanxi Creek in Chongqing was selected to be the study site. The water level, temperature, dissolved oxygen, pH, specific conductance, and selected ions concentrations of the river water, lateral hyporheic zone, and groundwater were monitored during the transitional period of wet season to dry season （ October to December）. Results show that the water level of the lateral hyporheic zone was changed greatly with the arriving of dry season. The water level gradient decreased be- tween river and hyporheic zone, resulting in a reduction of infiltration from the river water. Because of change of water level and temperature drop of infiltrated water, the microbial activities in the lateral hyporheic zone declined, which increases pH and decreases dissolved oxygen. These changes also reduced the specific conductance and weakened the purification capacity of the lateral hyporheic zone to nitrate and sulfate, and enhanced the fixation capacity to the heavy metals, like manganese and zinc. Based on the analysis of the geochemical dynamics of the hyporheic zone, it can be deduced that the boundary of the hyporheic zone was shifted from a place of 30--50 cm in the wet season to a place of less than 30 cm away from the riverbank in the dry season.

关 键 词：侧向交互带 水位变化 地球化学 马鞍溪 河水 地下水 

分 类 号：P592[天文地球—地球化学]