Hyporheic and Parafluvial Zones in… The Arctic Tundr a!
Feb 19, 2016
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