Nonlinear quickflow response as indicators of runoff generation mechanisms

  • Authors: Scaife, Charles I; Singh, Nitin; Emanuel, Ryan; Miniat, Chelcy F.; Band, Lawrence
  • Publication Year: 2020
  • Publication Series: Scientific Journal (JRNL)
  • Source: Hydrological Processes

Abstract

Linking quickflow response to subsurface state can improve our understanding of runoff processes that drive emergent catchment behavior. We investigated the formation of nonlinear quickflows in three forested headwater catchments and also explored unsaturated and saturated storage dynamics, and likely runoff generation mechanisms that contributed to their formation. Our analyses focused on two reference watersheds at the Coweeta Hydrologic Laboratory (CHL) in western North Carolina, USA and one reference watershed at the Susquehanna Shale Hills Critical Zone Observatory (SHW) in Central Pennsylvania, USA with available hourly soil moisture, groundwater, streamflow, and precipitation time series over several years. Our study objectives were to characterize 1) nonlinear runoff response as a function of storm characteristics and antecedent conditions, 2) the critical levels of shallow unsaturated and saturated storage that lead to hourly flow response, and 3) runoff mechanisms contributing to rapidly increasing quickflow using measurements of soil moisture and groundwater. We found that maximum hourly rainfall did not significantly contribute to quickflow production in our sites, in contrast to prior studies, due to highly conductive forest soils. Soil moisture and groundwater dynamics measured in hydrologically representative areas of the hillslope showed that variable subsurface states could contribute to non‐linear runoff behavior. Quickflow generation in watersheds at CHL were dominated by both saturated and unsaturated pathways, but the relative contributions of each pathway varied between catchments. In contrast, quickflow was almost entirely related to groundwater fluctuations at SHW. We showed that co‐located measurements of soil moisture and groundwater supplement threshold analyses providing stronger prediction and understanding of quickflow generation, and indicate dominant runoff processes.

  • Citation: Scaife, Charles I.; Singh, Nitin; Emanuel, Ryan; Miniat, Chelcy F.; Band, Lawrence. 2020. Nonlinear quickflow response as indicators of runoff generation mechanisms. Hydrological Processes. Hydrological Processes 34:2949-2964 . DOI 10.1002/hyp.13780
  • Keywords: antecedent soil moisture, Appalachian Mountains, emergent behaviour, forested catchments, piecewise linear regression, rainfall intensity, riparian groundwater wells, storage flux relationships
  • Posted Date: April 27, 2020
  • Modified Date: November 12, 2020
  • Print Publications Are No Longer Available

    In an ongoing effort to be fiscally responsible, the Southern Research Station (SRS) will no longer produce and distribute hard copies of our publications. Many SRS publications are available at cost via the Government Printing Office (GPO). Electronic versions of publications may be downloaded, printed, and distributed.

    Publication Notes

    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
    • Our online publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact the SRS webmaster if you notice any errors which make this publication unusable.
    • To view this article, download the latest version of Adobe Acrobat Reader.