An Analysis of River Bank Slope and Unsaturated Flow Effects on Bank Storage

Rebecca Doble, Philip Brunner, James McCallum, Peter Cook

    Research output: Contribution to journalArticle

    53 Citations (Scopus)

    Abstract

    Recognizing the underlying mechanisms of bank storage and return flow is important for understanding streamflow hydrographs. Analytical models have been widely used to estimate the impacts of bank storage, but are often based on assumptions of conditions that are rarely found in the field, such as vertical river banks and saturated flow. Numerical simulations of bank storage and return flow in river-aquifer cross sections with vertical and sloping banks were undertaken using a fully-coupled, surface-subsurface flow model. Sloping river banks were found to increase the bank infiltration rates by 98% and storage volume by 40% for a bank slope of 3.4° from horizontal, and for a slope of 8.5°, delay bank return flow by more than four times compared with vertical river banks and saturated flow. The results suggested that conventional analytical approximations cannot adequately be used to quantify bank storage when bank slope is less than 60° from horizontal. Additionally, in the unconfined aquifers modeled, the analytical solutions did not accurately model bank storage and return flow even in rivers with vertical banks due to a violation of the dupuit assumption. Bank storage and return flow were also modeled for more realistic cross sections and river hydrograph from the Fitzroy River, Western Australia, to indicate the importance of accurately modeling sloping river banks at a field scale. Following a single wet season flood event of 12 m, results showed that it may take over 3.5 years for 50% of the bank storage volume to return to the river.

    Original languageEnglish
    Pages (from-to)77-86
    Number of pages10
    JournalGroundwater
    Volume50
    Issue number1
    DOIs
    Publication statusPublished - Jan 2012

    Fingerprint Dive into the research topics of 'An Analysis of River Bank Slope and Unsaturated Flow Effects on Bank Storage'. Together they form a unique fingerprint.

  • Cite this