2003 Seattle Annual Meeting (November 2–5, 2003)

Paper No. 4
Presentation Time: 1:30 PM-5:30 PM

ANALYZING APPROPRIATE SAMPLING SCHEMES FOR d18O IN HYDROGRAPH SEPARATIONS


KORMOS, Patrick R., Geosciences, Boise State Univ, 1010 Floral Lane, Boise, ID 83712 and MCNAMARA, James P., Geosciences, Boise State Univ, 1910 University Dr, MG 225, Boise, ID 83725, patrickkormos@mail.boisestate.edu

d18O IS A WIDELY ACCEPTED CONSERVATIVE TRACER USED IN SEPARATING EVENT HYDROGRAPHS INTO NEW AND OLD WATER CONTRIBUTIONS TO STREAMFLOW. SNOWMELT EVENTS REQUIRE A LARGE NUMBER OF d18O MEASUREMENTS BECAUSE THE CONCENTRATION OF SNOWMELT IS TEMPORALLY VARIABLE THROUGHOUT A SPRING MELT. OBTAINING A LARGE NUMBER OF d18O SAMPLES IS LABOR INTENSIVE AND LABORATORY RESULTS ARE EXPENSIVE. THE NUMBER OF SNOWMELT d18O SAMPLES ANALYZED MAY BE MINIMIZED IF A SYSTEMATIC DIFFERENCE OR LACK OF DIFFERENCE IS OBSERVED BETWEEN SAMPLE LOCATIONS. SNOWMELT SAMPLES HAVE BEEN COLLECTED FROM TWELVE BUCKETS BURIED AT DIFFERENT ELEVATIONS AND ASPECTS IN A 0.2 KM2 MOUNTAINOUS CATCHMENT WITHIN THE DRY CREEK EXPERIMENTAL WATERSHED NORTH OF BOISE, ID. THIRTY-SIX SAMPLES FROM 6 DIFFERENT DAYS DURING A MELT EVENT WILL BE ANALYZED FOR d18O AND THE BENEFITS OF HAVING A HIGH SPATIAL AND TEMPORAL SAMPLING DENSITY WILL BE EVALUATED. BY MINIMIZING THE NUMBER OF SAMPLES ANALYZED THE COST OF AN EFFECTIVE HYDROGRAPH SEPARATION MAY BE MINIMIZED.