University of Alaska, Institute of Water Resources
Abstract
ERTS Project 110-5Snowmelt and rainfall floodinq is a major water resource problem in
Alaska. At the present time, forecastinq of these floods is based on a
sparse hydrological and climatological network. Numerous basins with
drainage areas of 5,000 km2 and less remain completely ungaged. The lack
of data causes uncertainty in the design of transportation schemes such as
tile Trans-Alaska oil pipeline. This project studied the utility of using
ERTS-l imagery as a source of additional data for the prediction of snowmelt
runoff, the most dynamic hydroloqic event in arctic and subarctic
basins. Snow distribution as determined from the satellite imagery was
compared with values determined from the conventional snow course stations
and with the results of a snowmelt energy model. The Chena River Basin
was selected because of the availability of ground truth data for comparison.
Very good agreement for snow distribution and rates of ablation was
found between the ERTS-l imagery, the snowmelt model, and field measurements.
Monitoring snowmelt rates for relatively small basins appears to be practical.
The main limitation of the ERTS-l imagery is the interval of coverage.
More frequent overflights providing coverage are needed for the study of
transient hydrologic events. ERTS-l data is most useful when used in conjunction
with snowmelt prediction models and existing snow course data.
These results should prove very useful in preliminary assessment of hydrologic
conditions in ungaged watersheds and will provide a tool for month-to-month
volume forecasting.This work was supported by National Aeronautics and Space Administration,
Grant NAS 5-21833