HR: 0800h
AN: C21B-0450 [Abstracts]
TI: Long-term changes in snow water equivalent and streamflow in northern Idaho
AU: * Link, T
EM: tlink@uidaho.edu
AF: University of Idaho, 975 W. 6th Street, Moscow, ID 83871, United States
AU: Luce, C
EM: cluce@fs.fed.us
AF: USFS Rocky Mountain Research Station, 322 E. Front St., Ste. 401, Boise, ID 83702, United
States
AU: Denner, B
EM: bdenner@fs.fed.us
AF: USFS Rocky Mountain Research Station, 1221 South Main Street, Moscow, ID 83843,
United States
AB:
Concern regarding the hydrologic impacts of climate warming in snow-dominated systems emphasizes the need
for long-term analyses of historical snowpack and streamflow data. Several studies have indicated a decline in
peak snow water equivalent (SWE), advance of seasonal meltout dates, and corresponding temporal advance in
snowmelt-dominated hydrographs in the inland northwest of the U. S. Analyses to date focused primarily on
snowpack records less than 50 years and on streamflow records from relatively large basins. There is a need to
assess trends over longer time periods and in smaller catchments to advance our understanding of the historical
hydrologic trends across a wider range of systems. An analysis of SWE and headwater streamflow trends at two
USFS experimental forests in northern Idaho is presented for data collected over the past 70 to 95 years. Both
annual and winter precipitation values exhibited a slightly increasing, but non-significant trend. SWE trends
indicated a consistent decline for most of the months of February through May. Statistically significant rates of
decline ranged from 0.7 to 3.8 mm yr-1. Over the period of record, these declines have resulted in
approximately 75% to 50% reductions in SWE at all sites during the melt season. Since the 1950's, annual
streamflow at one of the sites showed no significant trend, however the timing of the 50th percentile flow has
advanced approximately 12 days, which is comparable to larger basins in the area.
DE: 0736 Snow (1827, 1863)
DE: 0740 Snowmelt
DE: 1637 Regional climate change
DE: 1860 Streamflow
SC: Cryosphere [C]
MN: 2007 Fall Meeting