Shadow Mountain Dam is located approximately .8 miles upstream from the alpine glacial limit. The terminal moraine is located to the south of Grand Lake and is mapped as glacial drift. The dam is located in an area where recurrent glaciers mover various distances down the valleys and left a mantle on morainal materials over the older formations. Occasional ridges of glacial debris were deposited across the valleys as end moraines when the ice receded. Shadow Mountain Dam is located in one of these moraines. The upper foundation materials are described as undifferentiated glacial moraine deposits. The heterogeneous mixture of sand, gravel, cobbles and bounders with minor amounts of silt and clay are 28 to 38 feet thick. A 13 to 17 foot thick layer of silt with sand and sandy silt, described as alluvium, lies below the undifferentiated deposits. Underneath the silt layer is the Tertiary Age North Park Formation, consisting of a conglomertitic and tuffaceous sandstone. All the material above the bedrock is described as a glacial deposit.
General
Project
Colorado-Big Thompson
Longitude
-105.84102
Latitude
40.20785
Watercourse
Colorado River
Reservoir
Shadow Mountain
Original Construction
1944-1946
National ID Number
CO01666
Dimensions
Top of Inactive Conservation Pool (Elevation)
8366.0 ft
Crest Elevation
8375.0 ft
Hydraulic Height (Normal Operating Depth at Dam)
37.0 ft
Crest Length
3077.0 ft
Top of Active Conservation Pool (Elevation)
8367.0 ft
Top of Dead Storage Pool (Elevation)
8347.0 ft
Streambed at Dam Axis
8330.0 ft
Structural Height
63.0 ft
Spillway Crest Elevation
8348.0 ft
Hydraulics & Hydrology
Normal Water Surface Elevation
8367.0 ft
Auxiliary Spillway
No
Drainage Area
187.0 sq mi
Spillway Capacity at Elevation
10000 cfs at 8367.0 ft
Hydrometeorological Report (HMR)
HMR 49
Contact
Owner
Title: Area Office Manager Organization: Eastern Colorado Area Office Address: 11056 W. County Rd 18E City: Loveland, CO 80537-9711 Fax: 970-663-3212 Phone: 970-461-5410
Operator
Organization: Northern Colorado Water Conservancy District Address: 220 Water Ave. City: Berthoud, CO 80513 Phone: 800-369-7246
More Information about the U.S. Bureau of Reclamation