Rifle Gap Dam

Overview

Rifle Gap Dam is about 5 1/2 miles north of Rifle, at a point where Rifle Creek cuts through the Grand Hogback. The dam is an earthfill structure with a spillway. Rifle Gap Reservoir has a total capacity of 13,602 acre-feet and an active capacity of 12,168 acre-feet, and when full, a surface area of 359 acres.

Geology

Rifle Gap Dam is located at the head of a narrow canyon eroded through the Grand Hogback by Rifle Gap.  The hogback stands in relief above the adjacent topography because it is formed by Mesaverde sandstone and shale which are most resistant to erosion than formations an either side.  Mancos shale outcrops north of the hogbacks and forms a strike valley.  The soft Wasatch and Ohio Creek formations are found to the south and form valleys and badlands topography.  Prior to construction West Rifle Creek and East Rifle Creek merged to form Rifle Creek at a point approximately 400 feet downstream from the centerline of the dam.  Valley fill in the area is as thick as 120 feet or more.  The fill consists of coalescing stream deposits, alluvial fan material, and in the upper portions, variable thickness of glacial outwash fan material.  A considerable portion of the slopes above the valley are covered with slope wash.  A small northwest-southeast fault was mapped between the upper and lower axes during preliminary exploration.  The fault is located about 100 feet south of the downstream toe of the dam.  Records indicate that rock on either side of the fault is sheared in the left abutment.


General
RegionFacilities in Upper Colorado | Upper Colorado Home Page
StateColorado
CountyGarfield
ProjectSilt
Dam TypeZoned earthfill
ReservoirRifle Gap
WatercourseRifle Creek
Location5.5 miles north of Rifle, Colorado
Longitude-107.76025772094727
Latitude39.62720076390745
Original Construction1964-1967
Modified Construction
National ID NumberCO01692
Hydrologic Unit Code

Dimensions
Structural Height157 ft
Hydraulic Height (Normal Operating Depth at Dam)113.8 ft
Top Parapet (Elevation)
Spillway Crest Elevation5960.0 ft
Crest Elevation5978.00 ft
Crest Length1450.0 ft
Crest Width
Base Width
Volume of Dam Construction Materials1,768,000 cu yds
Streambed at Dam Axis5858.0 ft
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)5960.0 ft
Top of Inactive Conservation Pool (Elevation)5908.0 ft
Top of Dead Storage Pool (Elevation)5903.0 ft

Hydraulics & Hydrology
Total Water Storage at Elevation 13,602 ac ft at El 5960
Maximum Water Surface Elevation5971.8 ft
Normal Water Surface Elevation
Spillway Type
Auxiliary SpillwayNo
Spillway Capacity at Elevation3645.0 cfs at 5971.8 ft
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation326.0 cfs at 5971.8 ft
Diversion Capacity at Elevation
Drainage Area136 sq mi
Hydrometeorological Report (HMR)HMR 49
Probable Maximum Flood (PMF) Report

Contact Information
Owner
TitleArea Office Manager
OrganizationWestern Colorado Area Office
Address2764 Compass Drive, Suite 106
CityGrand Junction, CO 81506
Phone (Office)970 248-0600
Operator
OrganizationSilt Water Conservancy District
AddressPO Box 8
CitySilt, CO 81652
Phone (Fax)970 876-2874
Phone (Office)970 876-2393


Last updated: Nov 03, 2009