Geomorphology, hydrology, and aquatic vegetation drive seasonal hyporheic flow patterns across a gravel-dominated floodplain

Krista L. Jones, Geoffrey C. Poole, William W. Woessner, Matt V. Vitale, Brian R. Boer, Scott J. O'Daniel, Steven A. Thomas, Brook A. Geffen

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Across 1.7 km2 of the Umatilla River floodplain (Oregon, USA), we investigated the influences of an ephemeral tributary and perennial 'spring channel' (fed only by upwelling groundwater) on hyporheic hydrology. We derived maps of winter and summer water-table elevations from data collected at 46 monitoring wells and 19 stage gauges and used resulting maps to infer groundwater flow direction. Groundwater flow direction varied seasonally across the floodplain and was influenced by main channel stage, flooding, the tributary creek, and the location and direction of hyporheic exchange in the spring channel. Hyporheic exchange in the spring channel was evaluated with a geochemical mixing model, which confirmed patterns of floodplain groundwater movement inferred from water-table maps and showed that the spring channel was fed predominantly by hyporheic water from the floodplain aquifer (87% during winter, 80% during summer), with its remaining flow supplied by upslope groundwater from the adjacent catchment aquifer. Summertime growth of aquatic macrophytes in the spring channel also influenced patterns of hyporheic exchange and groundwater flow direction in the alluvial aquifer by increasing flow resistance in the spring channel, locally raising surface water stage and adjacent water-table elevation, and thereby altering the slope of the water-table in the hyporheic zone. The Umatilla River floodplain is larger than most sites where hyporheic hydrology has been investigated in detail. Yet, our results corroborate other research that has identified off-channel geomorphic features as important drivers of hyporheic hydrology, including previously published modeling efforts from a similar river and field observations from smaller streams.

Original languageEnglish (US)
Pages (from-to)2105-2113
Number of pages9
JournalHydrological Processes
Issue number13
StatePublished - Jun 30 2008
Externally publishedYes


  • Alluvial aquifer and streams
  • Aquatic macrophytes
  • Channel roughness
  • Groundwater and surface water interactions
  • Hydrogeology
  • Oregon
  • Umatilla river

ASJC Scopus subject areas

  • Water Science and Technology


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