Ririe Dam


Ririe Dam is located on Willow Creek, a minor tributary of the Snake River, in Bonneville County of eastern Idaho. The dam is 15 miles northeast of the city of Idaho Falls and about 4 miles southeast of the town of Ririe. Constructed by the Corps of Engineers, the dam is an earth and rockfill structure, 253 feet high and 1,070 feet long. The reservoir impounded by the dam has a total capacity of 100,500 acre-feet (active 90,500 acre-feet).



Ririe is located in the Willow Creek Drainage on the western flank of the Caribou Range of the Middle Rocky Mountains. The stream flows from the southeast to the northwest and enters the adjoining Snake River Plain about three miles below Ririe Dam. The upper watershed is an area underlain by Paleozoic and Mesozoic age rocks, mainly of sedimentary origin. The lower watershed near the damsite is an erosion-dissected plateau surface, which is slightly tilted toward the northeast. The plateau into which Willow Creek is entrenched is comprised of Pleistocene volcanic flows and intercalated sediments which, in turn rest with angular unconformity on the regional widespread Salt Lake Formation. This formation, identified locally as "basalt sediments", is a Pliocene age unit of continental origin with highly variable lithology. The surface of the volcanic rocks is often overlain by a variable thickness of unconsolidated, windblown silt deposits. At the damsite Willow Creek has entrenched itself 250 feet below the surrounding plateau surface. The floor of the river valley under normal conditions is about 550 feet wide and nearly level at elevation 4,960, with the meandering stream channel incised about 5 to 10 feet into alluvial deposits.  The valley alluvium is about 70 to 90 feet deep and is underlain by the canyon wall basalt sequence, except where erosion and faulting have exposed the underlying basal sediment formation.

RegionFacilities in Pacific Northwest | Pacific Northwest Home Page
Dam TypeEarth and Rockfill
WatercourseWillow Creek
Original Construction1970-1977
Modified Construction
National ID NumberID00344
Hydrologic Unit Code

Structural Height253.0 ft
Hydraulic Height (Normal Operating Depth at Dam)169.0 ft
Top Parapet (Elevation)
Spillway Crest Elevation5119.0 ft
Crest Elevation5128.0 ft
Crest Length1070.0 ft
Crest Width
Base Width
Volume of Dam Construction Materials
Streambed at Dam Axis4950.0 ft
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)5112.8 ft
Top of Active Conservation Pool (Elevation)5112.8 ft
Top of Inactive Conservation Pool (Elevation)5023.0 ft
Top of Dead Storage Pool (Elevation)4997.0 ft

Hydraulics & Hydrology
Total Water Storage at Elevation90,500 ac-ft
Maximum Water Surface Elevation
Normal Water Surface Elevation5112.8 ft
Spillway Typeradial gates
Auxiliary SpillwayNo
Spillway Capacity at Elevation40,000 cfs at 5119.0 ft
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation4,250 cfs
Diversion Capacity at Elevation
Drainage Area487.00 sq mi
Hydrometeorological Report (HMR)HMR 43
Probable Maximum Flood (PMF) Report

Contact Information
OrganizationUpper Snake Field Office 
Address470 22nd Street
CityHeyburn, ID 83336
Phone (Fax) 208 678-4321 
Phone (Office)208 678-0461
OrganizationUpper Snake Field Office 
Address470 22nd Street
CityHeyburn, ID 83336
Phone (Fax) 208 678-4321 
Phone (Office)208 678-0461

Last updated: Oct 25, 2012