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 Lewiston Orchards Project 
 Engineering Data

Lewiston Orchards Project  -  Main Page

Facilities in Operation

Storage Dams

2      

Diversion Dams

4      

Canals (irrigation)

19 mi  

Laterals (irrigation, pipeline)

88 mi  

Pumping Plants (irrigation)

1      

Domestic pipelines

58 mi  

Wells (domestic)

1      


Storage Facilities

Diversion Facilities

Webb Creek Diversion Dam

Type:

Rockfill weir, concrete crest wall

Location

On Webb Creek, about 15 miles south-east of Lewiston, Idaho.

Year Completed

1948  

Dimensions:

 

   Structural height

20 ft  

   Hydraulic height

10 ft  

   Crest length

75 ft  

   Crest elevation

3,599.0 ft  

   Volume

1,300 yd³  

Headworks:

30-in concrete pipe in 30-in concrete sluice pipe, controlled by 30-in intake and sluice gates, respectively

   Diversion capacity

20 cfs  


Sweetwater Diversion Dam

Type:

Rockfill weir, concrete crest wall.

Location

On Sweetwater Creek, about 12 miles southeast of Lewiston, Idaho.

Year Completed

1948  

Dimensions:

 

   Structural height

12 ft  

   Hydraulic height

8 ft  

   Crest length

80 ft  

   Crest elevation (approximate)

2,075.0 ft  

   Volume

7,500 yd3  

Headworks:

5- by 4-ft slide gate, concrete flume, and sand trap.

   Diversion capacity

77 cfs  


Other Diversion Structures

Captain John Diversion Dam, at the head of Captain John Feeder Canal, supplements the water supply for Soldiers Meadow Reservoir. This dam was built by the Irrigation District in 1934 out of log cribs following a simple standard design. The dam is about 50 mi south of Lewiston, Idaho, and is still in use.

The diversion dam at the head of Lake Waha Feeder Canal was constructed by the Irrigation District in 1912 and replaced by a concrete structure about 1941. The dam is on the West Fork of Sweetwater Creek, about 23 mi southeast of Lewiston.

Carriage Facilities

Webb Creek Diversion Conduit and Canal

Location

From Webb Creek Diversion Dam, about 15 miles southeast of Lewiston, Idaho, generally northwest to East Fork of Sweetwater Creek

Construction period

Work by Reclamation consisted of replacing sections of deteriorated wooden flume with 7,800 ft of 30-in precast concrete pipe, and constructing about 500 ft of earth-lined canal in 1947-1948.

Length

2.5 mi  

Capacity

20 cfs  

Typical section, earth lined:

 

   Bottom width

6 ft  

   Side slopes

1.5:1  

   Water depth

1.9 ft  

   Lining thickness

6 in  


Sweetwater Canal

Location

From Sweetwater Diversion Dam on Sweetwater Creek about 12 miles southeast of Lewiston, Idaho, generally north to Reservoir "A."

Construction period

1948-1949  

Length

9 mi  

Capacity

20 cfs  

Typical section (flume):

 

   Bottom width

5 ft  

   Water depth

3.5 ft  

   Wall thickness

6 in  

Typical section (canal):

 

   Bottom width

8 ft  

   Side slopes

1.5:1  

   Water depth

3.2 ft  


Main Pipeline  -  Reservoir "A"

Location

From Reservoir "A" outlet works west to Lewiston Orchards distribution system.

Construction period

1948-1949  

Length

4.4 mi  

Description:

4,450 ft of 36.5-in outside-diameter enameled welded steel pipe to water treatment plant; 18,900 ft of 30.5-in pipe to end of line.


Irrigation Distribution System

In addition to 4.4 miles of large steel supply lines, 71.2 miles of pressure pipe ranging from 1 to 30 inches in diameter were installed by the Irrigation District totaling 12 miles.

Domestic Distribution System

The domestic distribution system consists of 47 miles of pipeline ranging in diameter from 9.75 to 14 in installed by Reclamation and 11 mi of extension installed by the Irrigation District.

 

 

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