Black Canyon Diversion Dam

Overview

Black Canyon Diversion Dam, on the Payette River near Emmett, Idaho, is a concrete gravity type dam with an ogee overflow spillway. The dam has a structural height of 183 feet and serves to divert water to the Payette Division through Black Canyon Canal. The original capacity was 44,700 acre-feet but heavy siltation has reduced the capacity. At full pool there is now a volume of 31,200 acre-feet. Water is diverted at Black Canyon Diversion Dam by gravity into the Black Canyon Main Canal on the south side of the Payette River and by two direct connected turbine-driven pumps, located in the powerhouse, to serve the Emmett Irrigation District Canal on the north side of the river. The two unit powerplant had an initial total capacity of 8,000 kilowatts. The unit’s electrical components were upgraded to 5,100 kilowatts each in 1995 to provide the capability of generating 10,200 kilowatts with further upgrade of the turbines. Present generating capacity however, is limited to about 10,000 kilowatts. The plant supplies power to the Southern Idaho Federal Power System for Bureau of Reclamation project uses and for non-project purposes.

In 1998, a six-inch raise in Black Canyon Reservoir water surface was implemented by modifying the spillway drumgate and the radial gate at the Black Canyon Main Canal headworks. This was done to improve regulation of irrigation diversions from Black Canyon Reservoir to the Black Canyon Main Canal and to conserve the amount of stored water released from upstream reservoirs to meet fluctuating irrigation demands.

Geology

Foundation:  Primarily basalt flow ranging in thickness from about 100 feet at the left abutment to founded on sedimentary units (which underlie the basalt) at the right abutment.


General
RegionFacilities in Pacific Northwest | Pacific Northwest Home Page
StateIdaho
CountyGem
ProjectBoise
Dam Type Concrete gravity
ReservoirBlack Canyon
WatercoursePayette River
Location5 mi NE of Emmett, ID
Longitude-116.43756
Latitude43.9314
Original Construction1922-1924
Modified Construction1951-1952, 1955
National ID NumberID00282
Hydrologic Unit Code

Dimensions
Structural Height183 ft
Hydraulic Height (Normal Operating Depth at Dam)112.0 ft
Top Parapet (Elevation)
Spillway Crest Elevation
Crest Elevation2500.0 ft
Crest Length
Crest Width
Base Width
Volume of Dam Construction Materials81,200 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)
Top of Inactive Conservation Pool (Elevation)
Top of Dead Storage Pool (Elevation)

Hydraulics & Hydrology
Total Water Storage at Elevation31,200 acre-ft at 2498.0
Maximum Water Surface Elevation2500.0 ft
Normal Water Surface Elevation 2498.0 ft
Spillway Type Ogee crest controlled by three 64-foot-long steel drum gates
Auxiliary Spillway
Spillway Capacity at Elevation41,240 cfs at 2498.0 ft
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation2,420 cfs at 2498.0 sluice gates; 1,600 cfs Powerplant at 2498.0 ft
Diversion Capacity at Elevation 1,360 cfs diversion Black Canyon Canal at 2498.0 ft
Drainage Area2,680 sq mi
Hydrometeorological Report (HMR)HMR 43

Contact Information
Owner
TitleArea Office Manager
OrganizationSnake River Area Office
Address230 Collins Road
CityBoise, ID 83702-4520
Phone (Fax)208 383-2275
Phone (Office)208 383-2248
Operator
TitleArea Office Manager
OrganizationSnake River Area Office
Address230 Collins Road
CityBoise, ID 83702-4520
Phone (Fax)208 383-2275
Phone (Office)208 383-2248


Last updated: Oct 24, 2012