Basins tributary to the Snake River in the SR3 study area cover
parts of Idaho, Wyoming, Utah, Nevada, and Oregon. The Snake
River from Jackson Lake, Wyoming to Brownlee Dam, on the Idaho-
Oregon border, is nearly 700 miles long. The tributary basins,
combined with the east and west parts of the Snake River Plain,
drain more than 72,000 square miles (46,000,000 acres).
Depending on the scale or detail with which the Snake River
drainage system is examined, there are at least 60 separate
streams or drainages that connect to the main stem of the river
or at least deliver water to the Snake River Plain (Kjelstrom,
1986; Peterson, 1988). Jackson Lake is the beginning of the
Snake River. The lake is nestled at the base of the Teton
Mountains within Grand Teton National Park About 15,300 square
miles of the study area is associated with the Snake River Plain
with an additional 56,000 square miles within the hydrologic
units that extend up the tributary basins. Water in the Snake
River begins its journey flowing sout