Riverbed Clogging Associated with a California Riverbank Filtration System: An Assessment of Mechanisms and Monitoring Approaches

JOURNAL OF HYDROLOGY

卷:529

Article

Ulrich, Craig¹  Hubbard, Susan S.¹  Florsheim, Joan²  Rosenberry, Donald³  Borglin, Sharon¹  Trotta, Marcus⁴  Seymour, Donald⁴ 

[1] Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA

[2] Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA

[3] US Geol Survey, Berkeley, CA USA

[4] Sonoma Cty Water Agcy, Santa Rosa, CA USA

关键词: Riverbank filtration;    Riverbed clogging;    Riverbed permeability;    Thermal seepage;    Electrical resistivity;    Seepage meter;   

DOI  :  10.1016/j.jhydrol.2015.08.012

来源: Elsevier

【 摘 要 】

An experimental field study was performed to investigate riverbed clogging processes and associated monitoring approaches near a dam-controlled riverbank filtration facility in Northern California. Motivated by previous studies at the site that indicated riverbed clogging plays an important role in the performance of the riverbank filtration system, we investigated the spatiotemporal variability and nature of the clogging. In particular, we investigated whether the clogging was due to abiotic or biotic mechanisms. A secondary aspect of the study was the testing of different methods to monitor riverbed clogging and related processes, such as seepage. Monitoring was conducted using both point-based approaches and spatially extensive geophysical approaches, including: grain-size analysis, temperature sensing, electrical resistivity tomography, seepage meters, microbial analysis, and cryocoring, along two transects. The point monitoring measurements suggested a substantial increase in riverbed biomass (2 orders of magnitude) after the dam was raised compared to the small increase (similar to 2%) in fine-grained sediment. These changes were concomitant with decreased seepage. The decreased seepage eventually led to the development of an unsaturated zone beneath the riverbed, which further decreased infiltration capacity. Comparison of our time-lapse grain-size and biomass datasets suggested that biotic processes played a greater role in clogging than did abiotic processes. Cryocoring and autonomous temperature loggers were most useful for locally monitoring clogging agents, while electrical resistivity data were useful for interpreting the spatial extent of a pumping-induced unsaturated zone that developed beneath the riverbed after riverbed clogging was initiated. The improved understanding of spatiotemporally variable riverbed clogging and monitoring approaches is expected to be useful for optimizing the riverbank filtration system operations. Published by Elsevier B.V.

【 授权许可】

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