Shadow Mountain Dam

Shadow Mountain Dam is located approximately .8 mi 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.

RegionFacilities in Great Plains | Great Plains Home Page
ProjectColorado-Big Thompson
Dam Type
ReservoirShadow Mountain
WatercourseColorado River
Original Construction1944-1946
Modified Construction
National ID NumberCO01666
Hydrologic Unit Code

Structural Height63.0 ft
Hydraulic Height (Normal Operating Depth at Dam)37.0 ft
Top Parapet (Elevation)
Spillway Crest Elevation8348.0 ft
Crest Elevation8375.0 ft
Crest Length3077.0 ft
Crest Width
Base Width
Volume of Dam Construction Materials
Streambed at Dam Axis8330.0 ft
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)8367.0 ft
Top of Inactive Conservation Pool (Elevation)8366.0 ft
Top of Dead Storage Pool (Elevation)8347.0 ft

Hydraulics & Hydrology
Total Water Storage at Elevation
Maximum Water Surface Elevation
Normal Water Surface Elevation8367.0 ft
Spillway Type
Auxiliary SpillwayNo
Spillway Capacity at Elevation10000 cfs at 8367.0 ft
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation
Diversion Capacity at Elevation
Drainage Area187.0 sq mi
Hydrometeorological Report (HMR)HMR 49
Probable Maximum Flood (PMF) Report

Contact Information
TitleArea Office Manager
OrganizationEastern Colorado Area Office
Address11056 W. County Rd 18E
CityLoveland, CO 80537-9711
Phone (Fax)970 663-3212
Phone (Office)970 667-4410
OrganizationNorthern Colorado Water Conservancy District
AddressPO Box 679
CityLoveland, CO 80539
Phone (Office)970 667-2437

Last updated: Apr 08, 2013