Sun River Diversion Dam

The Sun River Diversion Dam, located 3 miles downstream from Gibson Dam, is a concrete arch structure with a structural height of 132 feet and a crest length of 261 feet. The dam contains 6,500 cubic yards of concrete. It is equipped with an overflow crest for a spillway. The outlet works tunnel runs through the canal wall of the right abutment. the capacity of the outlet works feeding the Pishkun Supply Canal is 1,400 feet per second.

RegionFacilities in Great Plains | Great Plains Home Page
CountyTeton, Lewis and Clark
ProjectSun River
Dam Type Concrete arch weir
WatercourseNorth Fork Sun River
Location On the North Fork of Sun River, 17 miles north west of Augusta, Montana, three miles downstream from Gibson Dam.
Original Construction1915
Modified Construction
National ID NumberMT00585
Hydrologic Unit Code

Structural Height132.00 ft
Hydraulic Height (Normal Operating Depth at Dam)114.00 ft
Top Parapet (Elevation)
Spillway Crest Elevation
Crest Elevation4,474.00 ft
Crest Length261.00 ft
Crest Width7.50 ft
Base Width40.00 ft
Volume of Dam Construction Materials6,500 cu yds
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 Elevation
Maximum Water Surface Elevation
Normal Water Surface Elevation
Spillway Type Overflow crest
Auxiliary Spillway
Spillway Capacity at Elevation
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation 34,000 cfs at 4,474.00 ft
Outlet Works Capacity at Elevation
Diversion Capacity at Elevation 1,400 cfs at 4,474.00 ft
Drainage Area
Hydrometeorological Report (HMR)
Probable Maximum Flood (PMF) Report

Contact Information
TitleArea Manager
OrganizationMontana Area Office
AddressP.O. Box 30137
CityBillings, MT 59107-0137
Phone (Fax)406 247-7338
Phone (Office)406 247-7300
OrganizationGreenfields Irrigation District
AddressBox 157
CityFairfield, MT 59436
Phone (Office)406 467-2533

Last updated: Apr 02, 2013