Portneuf River (Idaho) - Watershed and Discharge

Watershed and Discharge

The Portneuf watershed drains 850,290 acres (3,441.0 km2) in southeastern Idaho and is bounded by Malad Summit to the south, the Bannock Range to the west, the Portneuf Range to the southeast, and the Chesterfield Range to the northeast. Marsh Creek is the only major tributary to the Portneuf River. Other creeks in this watershed include Mink, Rapid, Garden,Hawkins, Birch, Dempsey, Pebble, Twentyfourmile, and Toponce creeks. The total area of the Chesterfield Reservoir is estimated at 1,236 acres (500 ha).

The Portneuf River's drainage basin is approximately 1,329 square miles (3,442 km2) in area.

Its mean annual discharge, as measured by USGS gauge 13075910 (Portneuf River at Tyhee), is 418 cubic feet per second (11.8 m3/s), with a maximum daily recorded flow of 1,730 cu ft/s (49.0 m3/s) and a minimum of 32 cu ft/s (0.906 m3/s).