Jackson Lake Dam


Jackson Lake Dam, a temporary rockfilled crib dam was completed in 1907 by the Bureau of Reclamation at Jackson Lake to store 200,000 acre-feet for the Minidoka Project until the storage requirements could be determined. A portion of this dam failed in 1910, and in 1911 a concrete gravity structure with earth embankment wings was built at the site. The new dam increased storage capacity to 380,000 acre-feet. In 1916, further construction raised the dam 17 feet to a structural height of 65.5 feet, with a total storage capacity of 847,000 acre-feet (active 847,000 acre-feet).

Safety concerns were identified at the dam in the mid-1970s, and from 1977 to 1989 the level of Jackson Lake was maintained at a lower than normal level because of concerns for possible dam failure during an earthquake. The dam foundation was completely replaced using a technique called dynamic compaction, and a grout curtain was installed below the foundation. The combination water release structure/bridge was also replaced. This work was completed in 1989 under authority of Reclamation's Safety of Dams Act making the full capacity available again.


Foundation: Rock ledge about 30 feet thick underlain by a 10 foot layer of stiff, blue clay overlying second rock formation.

RegionFacilities in Pacific Northwest | Pacific Northwest Home Page
Dam TypeConcrete gravity / zoned embankment
ReservoirJackson Lake
WatercourseSnake River
Original Construction1912
Modified Construction1916, 1986-1988
National ID NumberWY01385
Hydrologic Unit Code

Structural Height65.5 ft
Hydraulic Height (Normal Operating Depth at Dam)42.0 ft
Top Parapet (Elevation)
Spillway Crest Elevation6769 ft
Crest Elevation6774.5.0 ft
Crest Length4920.0 ft
Crest Width24.0 ft
Base Width72.0 ft
Volume of Dam Construction Materials
Streambed at Dam Axis
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)6769.0 ft
Top of Inactive Conservation Pool (Elevation)
Top of Dead Storage Pool (Elevation)

Hydraulics & Hydrology
Total Water Storage at Elevation 847,000 ac-ft
Maximum Water Surface Elevation6770.3 ft
Normal Water Surface Elevation 6769.0 ft
Spillway Type gated
Auxiliary Spillway
Spillway Capacity at Elevation8,690 cfs at 6769.0 ft
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation24,000 cfs at 6769.0 ft
Diversion Capacity at Elevation
Drainage Area1824.0 sq mi
Hydrometeorological Report (HMR)
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 29, 2012