Hungry Horse Dam

Overview

Hungry Horse Dam is 564-feet-high and has a variable-thickness concrete arch structure with a crest length of 2,115 ft. The dam and appurtenant works contain 3,086,200 cubic yards of concrete. The spillway is the highest morning-glory structure in the world. Water cascading over the spillway rim drops a maximum distance of 490 feet. The capacity of the spillway is 50,000 cubic feet per second, and the reservoir has a total capacity of 3,468,000 acre-feet.

Geology

Foundation: Siyeh limestone in regular beds ranging from a few inches to several feet thick, made highly insoluble by impurities. Cut by one major and several minor shear zones, and one major bedding-plane slip.


General
RegionFacilities in Pacific Northwest | Pacific Northwest Home Page
StateMontana
CountyFlathead
ProjectHungry Horse
Dam TypeConcrete Thick Arch
ReservoirHungry Horse
WatercourseSouth Fork of Flathead River
Location9 miles SE of Columbia Falls, Montana
Longitude-114.013023376
Latitude48.34130
Net Generation1,379,192,500 kWh
Original Construction1948-1953
Modified Construction1994-1995
Hydrologic Unit Code
National ID NumberMT00565

Dimensions
Structural Height564.0 ft
Hydraulic Height (Normal Operating Depth at Dam)520.0 ft
Top Parapet (Elevation)
Spillway Crest Elevation3565.0 ft
Crest Elevation3548.0 ft
Crest Length2115.0 ft
Crest Width39 ft
Base Width330 ft
Volume of Dam Construction Materials2,934,500 cu yd
Streambed at Dam Axis
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)3560.0 ft
Top of Inactive Conservation Pool (Elevation)
Top of Dead Storage Pool (Elevation)

Hydraulics & Hydrology
Total Water Storage at Elevation3,467,179 acre-ft at 3560
Maximum Water Surface Elevation3562.3 ft
Normal Water Surface Elevation3336.0 ft
Spillway TypeGated Morning Glory
Auxiliary Spillway
Spillway Capacity at Elevation50,000 cfs at 3565.0 ft
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation14,040 cfs at 3565.0 ft
Outlet Works Capacity at Elevation14,000 cfs hollow-jet valves; 9,000 cfs powerplant
Diversion Capacity at Elevation
Drainage Area1640 sq mi
Hydrometeorological Report (HMR)

Contact Information
Owner
OrganizationGrand Coulee Power Office
AddressPO Box 620
CityGrand Coulee, WA 99133-0620
Phone (Fax)509 633-9138
Phone (Office)509 633-1360
Operator
OrganizationGrand Coulee Power Office
AddressPO Box 620
CityGrand Coulee, WA 99133-0620
Phone (Fax)509 633-9138
Phone (Office)509 633-1360


Last updated: Oct 18, 2013