PowerPointPrsentation

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Department of Forest Resources University of
Idaho, Moscow USA
Isotope mass balance Mica Creek
Paul Koeniger, Tim Link, John Marshall
03/28/2006 Mica Creek Group Meeting
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What we plan to do
Combination of watershed hydrology and isotope
techniques for an isotopic mass balance in
forested watersheds - Snow sampling / spring
snowmelt - Base flow sampling - Water vapour
- evaporation vs. transpiration (- Isotopes
as applied tracers soil water-xylem-transpirati
on)
Isotope hydrological mass balance (Mica
creek) PCP (ECE TCSW) RCR GWrCSW
/- DSWCSW C Isotope concentration P
precipitation R runoff E evaporation T
transpiration GWr groundwater (recharge) SW
soil water
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Isotopes inprecipitation available data
IAEA (2001).  GNIP Maps and Animations,
Accessible at http//isohis.iaea.org
Bowen (2003).  Accessible at http//www.waterisot
opes.org
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Isotopes in precipitation

• Three to 5 sampling points
• in monthly resolution (altitude effect)
• - Reference station in Moscow (weekly)
• Snow sampling campaign in winter
• Event sampling

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Isotopes in snow

• Altitude effect in snow
• Spatial variability
• Snow profiles
• Spring snowmelt event

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Stream flow
Clearwater River / Spalding
Isotopes in stream flowavailable data?
(Coplen and Kendall 2000 U.S. Geological Survey
Open-File Report 00-160)
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Stream flow

• Continuous (monthly) sampling at 3 to 5
  locations
• (control site, partial-, clear cut)
• Event sampling residence time distributions
• Base flow
• Isotope hydrological and hydro chemical
  characterization of base flow at Mica creek
  best in Sept. / Oct. 2006
• - Salt dilution discharge measurements
• - 18O, 2H (and 3H/3He or 3H)
• - Conductivity, pH, chloride, water chemistry

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Evaporation transpiration water vapor isotopes

• Soil water
• Continuously - should represent transpiration
• Transpiration
• Xylem
• Water labeling of sap flow
• with 18O possibilities for in situ
  equilibration techniques ??
• with 2H sugar exchange??
• Evaporation
• Water vapor collecting techniques

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Conclusions

• Water balance components are crucial for isotope
  mass balance
• Isotopes in precipitation reference station in
  Moscow -gt regionalization
• Isotopes in stream flow, soil water, xylem
  sampling is ongoing
• Isotopes in snow results are soon to come
• Evaporation / transpiration component is probably
  the biggest challenge