Institute of Hydraulic Engineering and Water Resources Management, Technische Universität Wien, E222/2, Karlsplatz 13, 1040 Vienna, Austria; Centre for Water Resource Systems, Technische Universität Wien, Karlsplatz 13, 1040 Vienna, Austria.
Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, N2L 3G1 Waterloo, ON, Canada.
Sci Total Environ. 2018 Jun 15;627:450-461. doi: 10.1016/j.scitotenv.2018.01.226. Epub 2018 Feb 3.
Characterization of surface water - groundwater interaction in riverbank filtration (RBF) systems is of decisive importance to drinking water utilities due to the increasing microbial and chemical contamination of surface waters. These interactions are commonly assessed by monitoring changes in chemical water quality, but this might not be indicative for microbial contamination. The hydrological dynamics of the infiltrating river can influence these interactions, but seasonal temperature fluctuations and the supply of oxygen and nutrients from the surface water can also play a role. In order to understand the interaction between surface water and groundwater in a highly dynamic RBF system of a large river, bacterial abundance, biomass and carbon production as well as standard chemical parameters were analyzed during a 20 month period under different hydrological conditions. In the investigated RBF system, groundwater table changes exhibited striking dynamics even though flow velocities were rather low under regular discharge conditions. Bacterial abundance, biomass, and bacterial carbon production decreased significantly from the river towards the drinking water abstraction well. The cell size distribution changed from a higher proportion of large cells in the river, towards a higher proportion of small cells in the groundwater. Although biomass and bacterial abundance were correlated to water temperatures and several other chemical parameters in the river, such correlations were not present in the groundwater. In contrast, the dynamics of the bacterial groundwater community was predominantly governed by the hydrogeological dynamics. Especially during flood events, large riverine bacteria infiltrated further into the aquifer compared to average discharge conditions. With such information at hand, drinking water utilities are able to improve their water abstraction strategies and react quicker to changing hydrological conditions in the RBF system.
地表水-地下水相互作用的特征对于饮用水供应公司来说至关重要，因为地表水的微生物和化学污染日益严重。这些相互作用通常通过监测水质的变化来评估，但这可能并不能说明微生物污染的情况。渗透河流的水文动态会影响这些相互作用，但季节性温度波动和地表水提供的氧气和养分也会起作用。为了了解大河中一个高度动态的河岸渗滤系统中的地表水与地下水之间的相互作用，在不同的水文条件下，对细菌丰度、生物量和碳产量以及标准化学参数进行了 20 个月的分析。在所研究的河岸渗滤系统中，尽管在正常流量条件下流速相当低，但地下水位变化表现出显著的动态。从河流到饮用水取水口，细菌丰度、生物量和细菌碳产量显著下降。细胞大小分布从河流中较大细胞的比例较高，变为地下水中小细胞的比例较高。尽管生物量和细菌丰度与河流中的水温及其他一些化学参数相关，但在地下水中则不存在这种相关性。相比之下，细菌地下水群落的动态主要受水文地质动态控制。特别是在洪水事件期间，与平均流量条件相比，大量的河流细菌渗透到含水层中。有了这些信息，饮用水供应公司能够改进其取水策略，并对河岸渗滤系统中的水文变化做出更快的反应。
