Hyporheic and Parafluvial Zones in… The Arctic Tundra!

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.

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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