Keyhole Dam

Overview
Three geologic units are exposed at Keyhole damsite:

1)Lakota sandstone which is soft to medium hard with considerable bedding and has a system of vertical joints that separates the bedrock into blocks or large masses.  The lower portion of the Lakota sandstone across the valley floor.

2)Fuson shale lies above Lakota sandstone.  It is dark-gray shale with sandy shale and sandstone zones.

3)Dakota sandstone (similar to Lakota) lies above the Fuson shale on both banks

Lakota sandstone forms the basal portion of both dam abutments with Fuson shale lying above the Lakota formation.  Dakota sandstone lies high on the abutments above the Fuson shale.  Dips of these strata are essentially horizontal at the damsite.  Over burden near the dam axis consists of clay, silt, sand, and minor quantities of fine gravel.

General
RegionFacilities in Great Plains | Great Plains Home Page
StateWyoming
CountyCrook
ProjectPSMBP-Keyhole
Dam Type
ReservoirKeyhole
WatercourseOffstream
Location
Longitude-104.7792
Latitude44.3819
Original Construction1950-1952
Modified ConstructionWY01380
National ID Number
Hydrologic Unit Code

Dimensions
Structural Height168.0 ft
Hydraulic Height (Normal Operating Depth at Dam)113.0 ft
Top Parapet (Elevation)
Spillway Crest Elevation4099.3 ft
Crest Elevation4134.0 ft
Crest Length
Crest Width
Base Width
Volume of Dam Construction Materials
Streambed at Dam Axis
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)4099.3 ft
Top of Inactive Conservation Pool (Elevation)4051.0 ft
Top of Dead Storage Pool (Elevation)4036.0 ft

Hydraulics & Hydrology
Volume
Total Water Storage at Elevation
Maximum Water Surface Elevation
Normal Water Surface Elevation4128.7 ft
Spillway Type
Auxiliary SpillwayNo
Spillway Capacity at Elevation10850 cfs at 4128.7 ft
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation1480.0 cfs at 4128.2 ft
Diversion Capacity at Elevation
Drainage Area
Hydrometeorological Report (HMR)
Probable Maximum Flood (PMF) Report

Contact Information
Owner
TitleArea Office Manager
OrganizationDakotas Area Office
AddressPO Box 1017
CityBismarck, ND 58501
Phone (Fax)701 250-4326
Phone (Office)701 250-4242
Operator
TitleArea Office Manager
OrganizationDakotas Area Office
AddressPO Box 1017
CityBismarck, ND 58501
Phone (Fax)701 250-4326
Phone (Office)701 250-4242


Last updated: Apr 02, 2013