Storage Dams (regulating)

1      

Canals

31.7 mi  

Laterals

64.8 mi  

Pumping Plants

1      

Tunnels

2.6 mi  

Drains

56.5 mi  

Location:

From Helena Valley Tunnel to Helena Valley Reservoir, terminating in Lake Helena.

Construction period:

1957-1958  

Length

31.7 mi  

Capacity (maximum)

300 cfs  

Typical section in earth:

    Bottom width

14 ft  

    Side slopes

1.5:1  

    Water depth

5.5 ft  

Location:

From a point 500 ft downstream from Canyon Ferry Dam westerly through the Spokane Hills to the Helena Valley Canal.

Construction period:

1957-1958  

Length

13,985 ft  

Capacity (maximum)

300 cfs  

Cross section:

Horseshoe

Diameter

7 ft  

Lining

Concrete

Designation

Number of units

Total capacity, cfs

Total dynamic head, ft

Total horsepower

Helena Valley

2

300

145

¹10,000