Monday, September 4, 2023

1949 50mw Canyon Ferry Dam and 1958 Helena Valley Pumping Plant on Missouri River near Helena, MT

Dam: (Satellite)
Pump House: (Satellite)
Water tunnel exit and canal head: (Satellite)
Irrigation Reservoir: (Satellite)

usbr_dam
"Canyon Ferry Dam and Power Plant are on the Missouri River about 1.5 miles downstream from the original Canyon Ferry Dam and the Montana Power Company's 6,700 kilowatt in the backwater Hauser Lake. The dam is a concrete gravity structure approximately 1,000 feet in length along the crest with a structural height of 225 feet. It contains 414,400 cubic yards of concrete. The spillway is an overflow section in the central portion of the dam, controlled by four radial gates. The spillway capacity is 150,000 cfs. The total capacity is 2,051,000 acre-feet at elevation 3,800.00. Four river outlets are in the spillway section of the dam. The maximum discharge capacity of these outlets is 9,500 cfs. One 156-inch-diameter pumping intake pipe is embedded in the concrete of the dam near the left abutment for the Helena Valley Pumping Plant. Three 162-inch-diameter penstock pipes for the power generating units are embedded in the dam near the right abutment. The power plant is on the right downstream toe of the dam adjacent to the spillway apron. It is of reinforced concrete construction and houses three 16,667-kilowatt vertical-shaft generators driven by 23,500-horsepower turbines."
 
usbr_powerhouse
[The head is 150' (46m). I could not find a flow rate for the turbines. Each has a 13.5' (4m) penstock.]

Mike S, Jun 2017

The previous dam:
HelenaHistory_dams

Jason Francis posted
This photo is of my great grandfather shutting down the masters at the original Canyon Ferry Dam near Helena, MT circa 1949. The old Canyon Ferry dam operated from about 1900 to 1949, supplying electric power to the city of Helena, as well as many surrounding mines. The old dam was replaced by the current dam, which is operated by the US Bureau of Reclamation.
Geoffrey Bradford: Could someone educate a neophyte here ? In the picture foreground are several levers right out of Dr Frankenstein’s lab- are those for opening/closing circuits and if so wouldn’t there be a significant arc every time they’re moved? I don’t think those devices do what I think they do lol!
Alan Taylor: Geoffrey Bradford Up above are contactors that are used to start and stop the machine. The disconnects [knife switches] are to isolate the machine so maintenance can be done on the contactors and machine (The white round cornered squares are part of the contactors Asbestos arc shields)
Kevin Carey: I like the marble front board. I remember seeing marble switchboards on other old installations.

Spring 2023
1:29 video @ 0:42

Summer 2023
1:29 video @ 0:15

The pumping plant is for irrigation and water supply, not hydro power storage.
usbr_pumping
"The Helena Valley Unit water supply is discharged from Canyon Ferry Reservoir, 17 miles east of Helena on the Missouri River. Helena Valley Pumping Plant, below Canyon Ferry Dam, lifts water by turbine-driven pumps to Helena Valley Tunnel. This water flows by gravity through the 2.7-mile tunnel under the Spokane Hills into Helena Valley. Helena Valley Canal conveys the water around the south, west, and north sides of the valley, terminating in a wasteway into Lake Helena. Helena Valley Reservoir, with an active capacity of 5,897 acre-feet, is located at mile 11 of the Helena Valley Canal. This reservoir regulates pumped water and supplies water through a two-level outlet works to the municipal works constructed by the city of Helena.
"Helena Valley Pumping Plant, 500 feet downstream from Canyon Ferry Dam, houses two 5,000-horsepower Francis type hydraulic turbines; each turbine is connected directly to a 150-cubic-foot-per-second centrifugal pump; the two pumps lift a total of 300 cubic feet per second of water to the inlet end of the Helena Valley Tunnel."

"The reservoir area upstream from the dam has been earth blanketed to reduce seepage from the reservoir, and pressure relief wells have been installed near the downstream toe of the dam. These measures have not been totally effective and other measures are being considered to relieve the uplift pressures on the downstream toe of the dam."


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