Journal
WATER RESOURCES RESEARCH
Volume 48, Issue -, Pages -Publisher
AMER GEOPHYSICAL UNION
DOI: 10.1029/2011WR011461
Keywords
-
Categories
Funding
- National Science Foundation [DEB 08-23380, EAR-0911435]
- U. S. Forest Service Pacific Northwest Research Station
- Oregon State University
- Natural Environment Research Council [ceh010010] Funding Source: researchfish
- Direct For Biological Sciences
- Division Of Environmental Biology [0823380] Funding Source: National Science Foundation
- Direct For Biological Sciences
- Emerging Frontiers [752017] Funding Source: National Science Foundation
- Directorate For Geosciences
- Division Of Earth Sciences [0911435] Funding Source: National Science Foundation
- Division Of Earth Sciences
- Directorate For Geosciences [1261005, 0747629] Funding Source: National Science Foundation
Ask authors/readers for more resources
Hyporheic hydrodynamics are a control on stream ecosystems, yet we lack a thorough understanding of catchment controls on these flow paths, including valley constraint and hydraulic gradients in the valley bottom. We performed four whole-stream solute tracer injections under steady state flow conditions at the H. J. Andrews Experimental Forest (Oregon, United States) and collected electrical resistivity (ER) imaging to directly quantify the 2-D spatial extent of hyporheic exchange through seasonal base flow recession. ER images provide spatially distributed information that is unavailable for stream solute transport modeling studies from monitoring wells alone. The lateral and vertical extent of the hyporheic zone was quantified using both ER images and spatial moment analysis. Results oppose the common conceptual model of hyporheic compression'' by increased lateral hydraulic gradients toward the stream. We found that the extent of the hyporheic zone increased with decreasing vertical gradients away from the stream, in contrast to expectations from conceptual models. Increasing hyporheic extent was observed with both increasing and decreasing down-valley (i.e., parallel to the valley gradient) and cross-valley (i.e., from the hillslope to the stream, perpendicular to the valley gradient) hydraulic gradients. We conclude that neither cross-valley nor down-valley hydraulic gradients are sufficient predictors of hyporheic exchange flux nor flow path network extent. Increased knowledge of the controls on hyporheic exchange, the temporal dynamics of exchange flow paths, and their the spatial distribution is the first step toward predicting hyporheic exchange at the scale of individual flow paths. Future studies need to more carefully consider interactions between spatiotemporally dynamic hydraulic gradients and subsurface architecture as controls on hyporheic exchange.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available