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Elgin. Library

TC

~ MISSOURI RIVER BASIN PROJECT

. -- _, Farwell Unit. Nebraska

UStf General Information

Sherman Dam is the principal feature of the Farwell unit. It was constructed to provide
storage of off-season flows for release during the irrigation season to supplement direct
flows as needed to assure some 52, 530 acres (21, 258 hectares) in central Nebraska,
an adequate water supply.

Sherman Dam

Type: Homogeneous earthfill

Location: 4. 5 miles (7. 2 kilometers) northeast of Loup City, Nebr. , on Oak Creek
Constructed: 1959-1962
Reservoir: Sherman
Total capacity to normal water surface level, elevation 2162 (658. 97 meters):

68, 211 acre-feet (84, 138, 000 cubic meters)
Active capacity: 57, 715 acre-feet (71, 191, 000 cubic meters)
Inactive capacity plus dead storage: 10, 496 acre-feet (12, 946, 000 cubic meters)
Surface area: 2, 845 acres (1, 151 hectares)
Maximum reservoir elevation: 2169. 7 (661. 32 meters)

Dam Dimensions

Structural height: 134 feet (40. 84 meters)
Height above streambed: 98 feet (29. 87 meters)
Top width: 30 feet (9. 14 meters)
Maximum base width: 610 feet (185. 93 meters)
Crest length: 4, 450 feet (1, 356. 36 meters)
Crest elevation: 2178. 0 (663. 85 meters)
Volume: 1, 892, 000 cubic yards (1, 447, 000 cubic meters)

Spillway

Located in the dam near the toe of the left abutment and consists of a drop inlet or morning- glory- type inlet structure, an 8-foot-diameter (2. 44-meter) concrete, circular conduit, a hydraulic-jump-type stilling basin structure, and an outlet channel. It is capable of discharging 1, 095 second-feet (31 cubic meters per second) back into Oak Creek.

Outlet Works

Located adjacent to spillway and consists of a drop-inlet-type inlet structure, 96-inch-
diameter (243. 8-centimeter) circular upstream pressure conduit with steel pipelining,
a gate chamber housing a 6-foot by 7-foot 6-inch (1. 83- by 2. 29-meter) high-pressure
gate, a downstream 12-foot-diameter (3.66-meter) horseshoe-shaped conduit containing
a 90-inch-diameter (228. 60-centimeter) steel outlet pipe and a passageway, a control
house enclosing two 4- by 5-foot (1. 22- by 1. 52-meter) high-pressure regulating gates
at the downstream toe of the dam, and a stilling basin that empties into the Farwell
Main Canal.

Arcadia Diversion Dam

Type: Concrete gate structure with embankment wings
Location: Middle Loup River
Year completed: 1960-1962
Dimensions:

Structural height: 36 feet (10. 97 meters)

Height above streambed: 8 feet (2. 44 meters)

Weir crest (spillway) length: 388. 5 feet (118. 49 meters)

Total crest length: J./7, 960 feet (2, 426. 20 meters)

Weir crest elevation: 2201. 00 (670. 86 meters)

Volume (cubic yards): 2/14, 000 (10, 704 cubic meters)

I/Includes length of desilting works.
2/Includes volume of desilting works.

_.

Gates: 'Z

Spillway: Twelve 30- by 10-foot (9.14- by 3.05-meter) radial gates
Sluiceway: One 14- by 10-foot (4. 27- by 3.05-meter) radial gate
Headworks: Two 20- by 7-foot (6.10- by 2.13-meter) radial gates
Diversion capacity: 850 second-feet (24. 07 cubic meters per second)

Sherman Feeder Canal
Length: 19.1 miles (30. 7 kilometers)

Capacity: 850 second-feet (24. 07 cubic meters per second)

Description: Most of its length either earth-lined or unlined with a maximum base width of 28 feet (8. 53 meters) and a maximum depth of 8. 5 feet (2. 59 meters)

Included as an integral part of the canal is the Sherman Tunnel. The concrete tunnel
is 2, 053 feet (625. 75 meters) in length with a circular cross section 11 feet 6 inches
(3. 53 meters) in diameter and having a designed capacity of 850 second-feet (24. 07
cubic meters per second)
Location: Headworks located in the Arcadia Diversion Dam and the terminal in the

Sherman Reservoir
Purpose: To convey water from the Middle Loup River to Sherman Reservoir

Farwell Canals

Radiating southeasterly from Sherman Dam are a group of canals which convey supplemental water to some 52, 530 acres (21, 258 hectares). The Farwell Main Canal, with an initial capacity of 960 second-feet (27.18 cubic meters per second) begins at the outlet works below Sherman Dam. This canal, in addition to supplying water to irrigable land, also supplies water to the Farwell South and Farwell Central Canals. The Farwell Canals, for the most part, have unlined earth sections and have maximum capacities as follows:

Farwell Main and Lower Main--37. 5 miles (60. 3 kilometers)--960 second-feet

(27.18 cubic meters per second) Farwell Central--18. 5 miles (29. 8 kilometers)--170 second-feet (4. 81 cubic meters

per second)

Farwell South and Upper South--39. 7 miles (63. 9 kilometers)--340 second-feet (9. 63 cubic meters per second)

Note: Metric equivalents are in parentheses ( ). See appendix E for conversion factors.

Frontispiece. --Aerial view of downstream face of Sherman Dam. Spillway outlet is at left, and control house, outlet works and beginning of Farwell Main Canal are in center. P-707-D-42952 FOREWORD

[graphic]

Technical records of design and construction are a series of publications which record the planning, design, construction, and initial operation of Bureau of Reclamation structures.

This technical record of design and construction for Sherman Dam is divided into three parts. Part I is devoted to general planning, historical information, a brief description of the features, a summary of costs and geology. In part n, there are three chapters covering the design of the various features and their components. Part HI contains one chapter on contract administration and one chapter comprising a concise narration of construction operations.

This technical record was prepared by the Technical and Foreign Services Branch of the Office of Chief Engineer in Denver, Colo., from final design reports submitted by the design branches, final construction reports and cost information submitted by the field offices, and various planning reports. Acknowledgment is gratefully made to the designers and field personnel for their contributions to this work.

There are occasional references to proprietary materials or products in this technical record. These must not be construed in any way as an endorsement, as the Bureau cannot endorse proprietary products or processes of manufacturers or the services of commercial firms for advertising, publicity, sales, or other purposes.

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