Upper Stillwater Dam


Upper Stillwater Dam is a roller compacted concrete gravity dam located on Rock Creek, about 31 miles northwest of Duchesne, Utah.


Foundation: The foundation consists of Pre-Cambrian sandstone and argillites with nearly  horizontal bedding planes. Most of the length of the dam bears on hard sandstone. Near each  abutment the dam bears on argillite, which overlies the sandstone.

RegionFacilities in Upper Colorado | Upper Colorado Home Page
ProjectCUP-Bonneville Unit
Dam TypeRoller compacted concrete
ReservoirUpper Stillwater
WatercourseRock Creek
Original Construction1983-1987
Modified Construction
National ID Number
Hydrologic Unit Code

Structural Height310 ft
Hydraulic Height (Normal Operating Depth at Dam)188.5 ft
Top Parapet (Elevation)
Spillway Crest Elevation
Crest Elevation8180.0
Crest Length2660 ft
Crest Width29 ft
Base Width177 ft
Volume of Dam Construction Materials1,490.000 cu yds
Streambed at Dam Axis 7987.0 ft
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation) 8272.0 ft
Top of Inactive Conservation Pool (Elevation) 8028.4 ft
Top of Dead Storage Pool (Elevation) 8010.0 ft

Hydraulics & Hydrology
Total Water Storage at Elevation
Maximum Water Surface Elevation8175.5 ft
Normal Water Surface Elevation
Spillway Type
Auxiliary Spillway
Spillway Capacity at Elevation7820 cfs at 8175.5
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation820 cfs at 8172 ft
Diversion Capacity at Elevation
Drainage Area102 sq mi
Hydrometeorological Report (HMR)HMR 49
Probable Maximum Flood (PMF) Report1985 Local Thunderstorm

Contact Information
TitleArea Office Manager
OrganizationProvo Area Office
Address302 East 1860 South
CityProvo, UT 84606-7317
Phone (Office)801 379-1101
OrganizationCentral Utah Water Conservancy District
Address355 West University Parkway
CityOrem, UT 84058-7303
Phone (Office)801 226-7100

Last updated: Jun 23, 2009