Jackson Gulch Dam

Overview

Jackson Gulch Dam is a rock-faced earthfill structure 180 feet high with a concrete cutoff wall. The reservoir is off-stream on Jackson Gulch, 5 miles north of Mancos, and has a total capacity of almost 10,000 acre-feet. The dam does not have a spillway. The 280-cubic-foot-per-second-capacity outlet works is a concrete pressure conduit from trashrack to gate chamber, and a steel pipe from gate chamber to two hollow jet valves. The Inlet Canal extends from the West Mancos River to the reservoir.

Geology

Below elevation 7790 on the left abutment and 7805 on the right abutment Jackson Gulch Dam will rest on a layer of wash composed of gravel, rock and clay-silt four to eleven feet thick, apparently quite impervious, overlying a sandy shale of varying degrees of hardness, and Dakota sandstone.  Above these elevations one test pit near each end of the dam shows two to five feet of soil, compacted clay and a few boulders overlying 28 to 32 feet of gravel and boulders, which in turn rest on shale.  Top soil and loam varies from 1 to 2.5 feet in depth.  In the valley bottom the silt is stripped above the dam axis to the sandstone.


General
RegionFacilities in Upper Colorado | Upper Colorado Home Page
StateColorado
CountyMontezuma
ProjectMancos
Dam Type
ReservoirJackson Gulch
WatercourseOffstream
Location
Longitude-108.2740831375122
Latitude37.39845994620459
Original Construction1942-1949
Modified Construction
National ID NumberCO01685
Hydrologic Unit Code

Dimensions
Structural Height180.0 ft
Hydraulic Height (Normal Operating Depth at Dam)154.0 ft
Top Parapet (Elevation)
Spillway Crest Elevation
Crest Elevation7831.0 ft
Crest Length1900.0 ft
Crest Width
Base Width
Volume of Dam Construction Materials1,710,000 cu. yards
Streambed at Dam Axis7671.0 ft
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)7825.0 ft
Top of Inactive Conservation Pool (Elevation)
Top of Dead Storage Pool (Elevation)7708.6 ft

Hydraulics & Hydrology
Total Water Storage at Elevation
Maximum Water Surface Elevation7825.0 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 Elevation280 cfs at 7825.0 ft
Diversion Capacity at Elevation
Drainage Area1.44 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
OrganizationMancos Water Conservancy District
Address42888 County Rd N
CityMancos, CO 81328
Phone (Office)303 533-7325


Last updated: Mar 05, 2009