Storage Dams

3      

Diversion Dams

2      

Canals

131 mi  

Laterals

479 mi  

Drains

257 mi  

Type:

Concrete arch weir

Location

On the North Fork of Sun River, 17 miles northwest of Augusta, Montana, 3 miles downstream from Gibson Dam.

Year Completed

1915  

Dimensions:

   Structure height

132 ft  

   Hydraulic height

114 ft  

   Crest width

7.5 ft  

   Base width

40 ft  

   Crest length

261 ft  

   Weir crest elevation

4,474.0 ft  

   Volume

6,500 yd³  

Spillway:

Overflow crest

   Capacity

34,000 cfs  

Headworks:

Concrete gate structure in right abutment, discharging into tunnel approximately 11 ft in diameter and 693 ft long. Two 5-by 10-ft steel slide gates, hand operated.

   Diversion capacity

1,400 cfs  

Type:

Rock overflow section

Location

On the Sun River, 12 miles upstream of Fort Shaw, Montana, 40 miles downstream from Sun River Diversion Dam.

Year Completed

1908  

Dimensions:

   Structure height

9 ft  

   Hydraulic height

9 ft  

   Crest length

400 ft  

   Approximate volume rock fill

3,000 yd³  

   Diversion capacity

225 cfs  

Location

From Sun River Diversion Dam, 3 miles downstream from Gibson Dam on the North Fork, Sun River, generally northeast to Pishkun Reservoir.

Construction period

1913-1920. Enlarged 1935-1938  

Length

12.1 mi  

Diversion capacity

1,400 cfs  

Typical section in earth:

   Bottom width

27 ft  

   Side slopes

1.5:1  

   Water depth

12 ft  

Location

On the Sun River near Sun River Diversion Dam.

Description:

Monolithic concrete siphon

Length

700 ft  

Diameter

10 ft  

Capacity

1,400 cfs  

Location

Along Pishkun Supply Canal

Diameter

10 ft  

Total length

3,260 ft  

Capacity

1,400 cfs  

Location

Southeast from Sun River Crossing entrance on Pishkun Supply Canal.

Construction period

1938  

Length

7.3 mi  

Diversion capacity

500 cfs  

Typical section in earth:

    Bottom width

14 ft  

    Side slopes

1.5:1  

    Water depth

4.5 ft  

Location

From Pishkun Reservoir generally southeast.

Construction period

1917-1919  

Length

25 mi  

Diversion capacity

1,600 cfs  

Typical section in earth:

    Bottom width

36 ft  

    Side slopes

1.5:1  

    Water depth

12.6 ft  

Typical section, concrete lined:

    Bottom width

12.33 ft  

    Side slopes

1:1  

    Water depth

10.7 ft  

    Lining thickness

4 in  

Location

East from a point on Sun River Slope Canal near its end, to vicinity of Fairfield, Montana.

Construction period

1931-1932  

Length

14.2 mi  

Diversion capacity

1,200 cfs  

Typical section in earth:

    Bottom width

40 ft  

    Side slopes

1.5:1  

    Water depth

8 ft  

Location

From end of Spring Valley Canal near Fairfield, Montana, generally northeast.

Construction period

1913-1920. Enlarged 1940.  

Length

27.4 mi  

Diversion capacity

1,200 cfs  

Typical section in earth:

    Bottom width

38 ft  

    Side slopes

1.5:1  

    Water depth

7.3 ft  

Location

From point on Greenfields Main Canal near Fairfield, Montana, generally east.

Construction period

1913-1920. Enlarged 1940.  

Length

14.6 mi  

Diversion capacity

425 cfs  

Typical section in earth:

    Bottom width

24 ft  

    Side slopes

1.33:1  

    Water depth

4 ft  

Location

East and south from Greenfields South Canal near Fairfield, Montana.

Construction period

1913-1920. Enlarged 1940.  

Length

10.7 mi  

Diversion capacity

200 cfs  

Typical section in earth:

    Bottom width

20 ft  

    Side slopes

1.5:1  

    Water depth

3 ft  

Location

From diversion on the Sun River about 5 mi west of Simms, Montana, generally east to vicinity of Sun River, Montana.

Construction period

1907-1908  

Length

12.1 mi  

Diversion capacity

225 cfs  

Typical section in earth:

    Bottom width

12 ft  

    Side slopes

1.5:1  

    Water depth

4 ft