History

The Helena Valley Irrigation District was built from 1956 through 1958 and was designed to reclaim land destroyed or inundated by the backing up of water from Canyon Ferry Dam. Other irrigation districts formed at the same time and for the same purpose were the East Bench Irrigation District (Dillon), and the Crow Creek Unit (Toston). Between the three irrigation districts enough land was irrigated to offset irrigated acres covered by water in Canyon Ferry Reservoir.

The HVID was built as a “Multi-Purpose” project. Its mission is not only to provide water to irrigate crop lands but also to provide municipal water for the City of Helena. Currently, the HVID irrigates approximately 18,000 acres and with the updates and capacity expansion of the Missouri River Water Treatment Plant, the mission of providing municipal water to the City of Helena continues to increase in importance.

The HVID consists of an enclosed pumping plant located just downstream of Canyon Ferry Dam. The plant receives its water through a penstock pipe out of Canyon Ferry Dam and goes directly into the intakes of the pumps. The intake penstock begins at 13’ diameter and reduces to 10’ diameter before it enters the plant. The water powers two water turbines that turn the centrifugal pump shafts to deliver water to the discharge canal system. The turbines can produce approximately 7000 horse power. The overhead of the HVID would be much higher if it had to pay electrical power bills for 7000 hp, but by being powered by water, the cost to pump water is very low. Each pump is capable of pumping 150 feet of head at 180 cfs. Combined, the output is 150 ft/hd @ 360 cfs. The discharge water is pumped through a 6’ discharge pipe which goes steeply up a mountain about 150’ in elevation. The pipe transitions into a 7’ horseshoe shaped concrete tunnel which travels 2.6 miles through the mountains. The water then empties into the main canal which travels approximately 8 miles to the Helena Valley Regulating Reservoir. The Helena Valley Regulating Reservoir’s purpose is to store water and has a capacity of about 10,000 acre feet of water. Two gates are operated and adjusted on a daily basis to add or reduce water flows into the canal leaving the regulating reservoir to irrigate the remainder of the Helena valley. There is also a city outlet located in the dam of the regulating reservoir which diverts water to the City of Helena, Missouri River Water Treatment Plant.

The main canal leaving the regulating reservoir is approximately 25 miles long and loops around the valley in a clockwise fashion and ends near the north east corner of Lake Helena. Coming off of the main canal are twenty smaller lateral ditches which deliver water throughout the entire valley and adds up to around 40 miles of additional ditch.

A series of underground (piped) and above ground (open ditch) drains also thread throughout the valley. The drains work to lower the water table so crops can be raised.

System

  1. 7,000 HP centrifugal pumps
  2. Pumps develop 400 cfs @ 150’ HD
  3. 10’ diameter intake penstock
  4. 6’ diameter outlet steel pipe
  5. 7’ concrete tunnel (2.6 miles)
  6. Reservoir, 10,000 ac/ft capacity
  7. Main Canal capacity, 360 cfs
  8. Acres irrigated, 18,000
  9. Diverts approximately 85,000 acre/feet annually
  10. Provide water for special projects such as, waterfowl nesting, soccer fields, wetland habitat, in-stream flows for Prickly Pear Creek

Helena Valley Irrigation District
3840 N. Montana Avenue
Helena, MT 59602
(406) 442-3292