Vega Dam

Overview

Vega Dam is near the Grand Mesa in western Colorado, about 10 miles east of the town of Collbran. The dam is a zoned, rolled earth and rockfill structure with a maximum height above foundation of 162 feet, a crest length of 2,100 feet, and a volume of 981,825 cubic yards of material. The outlet works is near the left abutment and consists of an intake structure, 5-foot diameter concrete pressure conduit, concrete gate chamber for a 3.5-foot-square high-pressure emergency gate, 8-foot-diameter concrete horseshoe conduit containing a 51-inch-diameter steel pipe, control house containing two 2.25-foot-square high-pressure control gates, concrete stilling basin, and an outlet channel which discharges into the Southside Canal.

Vega Reservoir has a surface area of about 900 acres, with a capacity of 33,800 acre-feet, and a shoreline of approximately 7 miles.

Geology

Collbran Project is located along the northeastern slope of Grand Mesa.  The mesa is composed of horizontally bedded, tertiary rocks belonging to the Wasatch and Green River formations and capped by lave flow of Quaternary basalt.  During Pleistocene times, sheet-like glaciers covered the mesa.  Glacial scouring produced the many small mesa lakes and the heterogeneous deposits of glacial debris, which mantle a large part of the surface rock.  These glacial deposits cover the lava in varying depths from one hundred to several hundred feet.  The Vega Damsite is in an erosional narrows cut across the toe of a large fan.  Overburden debris covers bedrock at the damsite to a depth of 135 feet, becoming progressively deeper to the south.  The fan is composed of clayey silt containing basalt boulders.  It is compact and seepage tests indicate that it is watertight.  Even with a high water table, little or no slumping of side slopes has occurred, and other field evidence indicates good stability.


General
RegionFacilities in Upper Colorado | Upper Colorado Home Page
StateColorado
CountyMesa
ProjectCollbran
Dam TypeZoned rolled earth, rockfill
ReservoirVega
WatercoursePlateau Creek
Location10 miles east of Collbran, CO
Longitude-107.81081199645996
Latitude39.222990274902536
Original Construction1957-1959
Modified Construction
National ID NumberCO01697
Hydrologic Unit Code

Dimensions
Structural Height162.0 ft
Hydraulic Height (Normal Operating Depth at Dam)110.7 ft
Top Parapet (Elevation)
Spillway Crest Elevation
Crest Elevation7997.0 ft
Crest Length2100.0 ft
Crest Width
Base Width
Volume of Dam Construction Materials981,825 cu yds
Streambed at Dam Axis7880.3 ft
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)7984.0 ft
Top of Inactive Conservation Pool (Elevation)7906.0 ft
Top of Dead Storage Pool (Elevation)7906.0 ft

Hydraulics & Hydrology
Total Water Storage at Elevation
Maximum Water Surface Elevation7990.0 ft
Normal Water Surface Elevation
Spillway Type
Auxiliary SpillwayNo
Spillway Capacity at Elevation
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation
Diversion Capacity at Elevation
Drainage Area24.4 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
OrganizationCollbran Conservancy District
AddressPO Box 163
CityCollbran, CO 81624
Phone (Office)970 487-3306


Last updated: Apr 10, 2009