Pathfinder Dam


Waters of the North Platte River must pass the Seminoe and Kortes Damns before entering the reservoir at Pathfinder Dam, which impounds the flow from Sweetwater River. Pathfinder Reservoir has a storage capacity of 1,016,000 acre-feet and holds much of the North Platte Project water. During the nonirrigation season, a small amount of water is released to satisfy other water rights, enhance fish and wildlife, and operate powerplants downstream. During the irrigation season, water is released as required, including water flowing from Seminoe Reservoir to be diverted at Alcova Dam for irrigation on the Kendrick Project.

Pathfinder Dam is one of the first constructed by the Reclamation Service. The dam is in a granite canyon on the North Platte River about 3 miles below its junction with the Sweetwater River and about 47 miles southwest of Casper, Wyo. It is made of granite quarried from nearby hills, and is faced with large rectangular blocks laid in horizontal courses. It is an arch dam with a gravity-type section, and has a structural height of 214 feet.

Pathfinder Dike fills a depression in the natural ground surface about0.25 miles south of the dam. It is an earth-fill structure, 38 feet high, with a concrete corewall.

Foundation: Coarse-grained, massive granite; local vertical crush zone at left abutment; some flat mud seams in canyon floor

RegionFacilities in Great Plains | Great Plains Home Page
ProjectNorth Platte
Dam Type Cyclopean masonry (granite)
WatercourseNorth Platte River
Location 47 miles southwest of Casper, WY
Net Generation
Original Construction1905-1909
Modified Construction1910-12, 1915, 1919-22, 1981, 1949-50, 1958-61, 1996-97
National ID NumberWY01296
Hydrologic Unit Code

Structural Height214.0 ft
Hydraulic Height (Normal Operating Depth at Dam)192.0 ft
Top Parapet (Elevation)
Spillway Crest Elevation
Crest Elevation5858.1 ft
Crest Length432.0 ft
Crest Width10.9 ft
Base Width96.5 ft
Volume of Dam Construction Materials65700 cu yd
Streambed at Dam Axis
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)
Top of Inactive Conservation Pool (Elevation)
Top of Dead Storage Pool (Elevation)

Hydraulics & Hydrology
Total Water Storage at Elevation1070000.0 acre-ft at 5852.49
Maximum Water Surface Elevation5858.1 ft
Normal Water Surface Elevation
Spillway Type
Auxiliary Spillway
Spillway Capacity at Elevation38000 cfs at 5858.1
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation3000.0 cfs at 5858.1 ft
Diversion Capacity at Elevation
Drainage Area14600.0 sq mi
Hydrometeorological Report (HMR)HMR 55A
Probable Maximum Flood (PMF) Report

Contact Information
TitleFacility Manager
OrganizationNorth Platte Projects Field Office
Address22122 Kortes Road
CityAlcova, WY 82620
Phone (Office)307-261-5960

Last updated: May 31, 2013