Hyporheic and Parafluvial Zones in…
The
Arctic
Tundra!
The hydraulic characteristics and geochemistry of hyporheic and
parafluvial zones in Arctic tundra streams, north slope, Alaska
Edwarson et al. (2003): Advances in Water Resources
Purpose: Investigate the hydrologic and chemical dynamics of hyporheic and parafluvial zones in Arctic tundra streams
Importance: Essentially no information on Arctic streams
– First comprehensive description of hyporheic and parafluvial zones in Arctic tundra streams
– Continuous permafrost• Limit the importance of hyporheic processes?
Scope of Work• 17 conservative tracer additions on 7
streams from 1994-1996– Stream reaches varied greatly
• Characterize in-stream hydrologic parameters using hyporheic samplers and OTIS-P simulations
• Biogeochemical and nutrient processing in hyporheic and parafluvial zones
Background: Definitions and Key Concepts
• Transient storage zones
• Parafluvial
• Beaded stream
• Importance of hyporheic and parafluvial zones
• 3 key factors that control water movement in these zones
• DO in the hyporheic zone
• Modeling limitations
Study Area
Study Area: Kuparuk R. and Oksrukuyik Cr.
KupafertilizedKupa
MouthOfKupa
Oks
Whole Lotta Methods:• Hyporheic Samplers
• Tracer Additions
• Conservative Tracer Analysis
• Solute Modeling
• Vertical Hydraulic Gradient (VHG)
• Nutrient Chemistry
http://pubs.usgs.gov/sir/2005/5255/section4.html
http://water.usgs.gov/ogw/gwrp/images/photos/rhodamineWT_injection.jpg
Results: OTIS Modeling
• No significant relationship between As/A and discharge – General relationship held true
• Average storage zone cross-sectional area of the Arctic streams– 43% (Range: 8 – 254%)– 32% (Range: 8 – 112%) without Imnavait Cr.
Results:Channel, Upwelling, and Downwelling Sites
Transient Storage Zones
Results: Channel, Upwelling, and Downwelling Sites
Tracer Penetration
Hyporheic
Parafluvial
Hyporheic
Parafluvial
Bottom of RiffleTop of Riffle
Results: Channel, Upwelling, and Downwelling Sites
Water Quality
Results: VHG and Temperature
VHG
Riffle Parafluvial zones in left and right point bars
Results: Benthic Uptake
Key Discussion Points and Conclusions
• Transient storage in Arctic Streams– Similarity to temperate regions
• As/A relationship not signifcant
– Δmorphology and Δstage height are boss.– Importance of eddies
• BUT hyporheic storage still muy importante!
– Biogeochemical importance of hyporheic flowpath.
• Permafrost– Hyporheic flow not limited by permafrost in ice-free
season– Spring ice-out (thaw) may results in much lower As/A
values due to high snow-melt Q and reduced interstitial area
• Water Quality– Interstitial waters served as sources of NO3, NH4,
PO4, and CO2
– Interstitial temperature inversely related to VHG and residence time in hyporheic and parafluvial zones.
Key Discussion Points and Conclusions
Questions?
NOQUESTIONS