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The importance and challenge of hyporheic mixing
Author(s) -
Hester Erich T.,
Cardenas M. Bayani,
Haggerty Roy,
Apte Sourabh V.
Publication year - 2017
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2016wr020005
Subject(s) - hyporheic zone , mixing (physics) , groundwater , surface water , hydrology (agriculture) , streams , environmental science , geology , soil science , geotechnical engineering , environmental engineering , computer network , physics , quantum mechanics , computer science
The hyporheic zone is the interface beneath and adjacent to streams and rivers where surface water and groundwater interact. The hyporheic zone presents unique conditions for reaction of solutes from both surface water and groundwater, including reactions which depend upon mixing of source waters. Some models assume that hyporheic zones are well‐mixed and conceptualize the hyporheic zone as a surface water‐groundwater mixing zone. But what are the controls on and effects of hyporheic mixing? What specific mechanisms cause the relatively large (>∼1 m) mixing zones suggested by subsurface solute measurements? In this commentary, we explore the various processes that might enhance mixing in the hyporheic zone relative to deeper groundwater, and pose the question whether the substantial mixing suggested by field studies may be due to the combination of fluctuating boundary conditions and multiscale physical and chemical spatial heterogeneity. We encourage investigation of hyporheic mixing using numerical modeling and laboratory experiments to ultimately inform field investigations.