Research Article

Effect of morphology and discharge on hyporheic exchange flows in two small streams in the Cascade Mountains of Oregon, USA

  1. Steven M. Wondzell*

Article first published online: 26 AUG 2005

DOI: 10.1002/hyp.5902

Issue

Hydrological Processes

Hydrological Processes

Volume 20, Issue 2, pages 267–287, 15 February 2006

Additional Information

How to Cite

Wondzell, S. M. (2006), Effect of morphology and discharge on hyporheic exchange flows in two small streams in the Cascade Mountains of Oregon, USA. Hydrological Processes, 20: 267–287. doi: 10.1002/hyp.5902

Author Information

  1. Olympia Forestry Sciences Laboratory, Pacific Northwest Research Station, USDA Forest Service, Olympia WA 98512, USA

*US Forest Service, Pacific Northwest Research Station, Olympia Forestry Science Lab, Olympia, WA 98512, USA.

Publication History

  1. Issue published online: 6 FEB 2006
  2. Article first published online: 26 AUG 2005
  3. Manuscript Accepted: 7 JAN 2005
  4. Manuscript Received: 23 OCT 2003

Funded by

  • National Science Foundation. Grant Numbers: EAR-9506669, BSR-90-11663, DEB-96-32921
  • H. J. Andrews Long-Term Ecological Research Program. Grant Number: DEB-9632921
  • USDA Forest Service, Pacific Northwest Research Station's Ecosystem Processes and Aquatic and Land Interactions Programs

SEARCH

SEARCH BY CITATION

ARTICLE TOOLS

Get PDF (275K)

Keywords:

  • hyporheic zone;
  • stream tracer experiments;
  • transient storage models;
  • groundwater

Abstract

Stream-tracer injections were used to examine the effect of channel morphology and changing stream discharge on hyporheic exchange flows. Direct observations were made from well networks to follow tracer movement through the hyporheic zone. The reach-integrated influence of hyporheic exchange was evaluated using the transient storage model (TSM) OTIS-P. Transient storage modelling results were compared with direct observations to evaluate the reliability of the TSM. Results from the tracer injection in the bedrock reach supported the assumption that most transient storage in headwater mountain streams results from hyporheic exchange. Direct observations from the well networks in colluvial reaches showed that subsurface flow paths tended to parallel the valley axis. Cross-valley gradients were weak except near steps, where vertical and cross-valley hydraulic gradients indicated a strong potential for stream water to downwell into the hyporheic zone. The TSM parameters showed that both size and residence time of transient storage were greater in reaches with a few large log-jam-formed steps than in reaches with more frequent, but smaller steps. Direct observations showed that residence times in the unconstrained stream were longer than in the constrained stream and that little change occurred in the location and extent of the hyporheic zone between low- and high-baseflow discharges in any of the colluvial reaches. The transient storage modelling results did not agree with these observations, suggesting that the TSM was insensitive to long residence-time exchange flows and was very sensitive to changes in discharge. Disagreements between direct observations and the transient storage modelling results highlight fundamental problems with the TSM that confound comparisons between the transient storage modelling results for tracer injections conducted under differing flow conditions. Overall, the results showed that hyporheic exchange was little affected by stream discharge (at least over the range of baseflow discharges examined in this study). The results did show that channel morphology controlled development of the hyporheic zone in these steep mountain stream channels. Copyright © 2005 John Wiley & Sons, Ltd.

Get PDF (275K)