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Wilbur A. Dexheimer, Commissioner
L. N. McClellan, Assistant Commissioner and Chief Engineer

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Engin. Library

TRENTON DAM Missouri River Basin Project--Nebraska

Dam (Continued)

Main cutoff trench: 50-foot base width

with 1-1/2 to 1 side slopes, length

about 6, 760 feet
Auxiliary cutoff trench: 50-foot base

width with 1-1/2 to 1 side slopes,
length about 570 feet


Type: Concrete overflow chute type

with stilling basin Crest length of overflow section: 126

feet Crest: Elevation 2743.00 Maximum discharge: 126, 500 secondfeet at water surface elevation 2785. 6

(as determined by model studies) Gates: Three, 42 by 30 feet Stilling basin: Reinforced concrete with dentated sills

558 General Information

Purpose: Flood control, diversion for .217 irrigation, storage, sedimentation TO

control, fish and wildlife preserva

tion, and recreation 1158 Location: On Republican River, about

2-1/2 miles west of Trenton, Nebr. Constructed: 1949-1953 Water supply: Republican River

Drainage area: 4,003 square

miles Maximum flood: 200,000 second

feet (May 31, 1935) Average yearly flow: 211 second

feet (1947-1952)

Official name: Swanson Lake
Area: 7,975 acres at elevation

Flood control storage: 133, 800
acre-feet, between elevations

2752.0 and 2773.0
Active irrigation storage: 116, 100
acre-feet, between elevations

2710.0 and 2752.0
Dead storage: 4, 100 acre-feet,
between elevations 2693.0 and


Type: Zoned rolled-earth fill
Foundation: Pierre shale
Slope protection: Riprap on gravel
blanket on upstream face, seeded
topsoil on downstream face

Height: 144 feet above lowest ex

cavation in cutoff trench, 100 feet above riverbed Crest length: 8, 600 feet Crest elevation: 2793.0 Crest roadway width: 30 feet Volume: 7,800,000 cubic yards Slopes: Upstream, 6 to i to elevation 2710, 3 to 1 to elevation 2760, and 2-1/2 to 1 to elevation 2793

Downstream, 10 to 1 to elevation 2710, 4 to 1 to elevation 2735, 2-1/2 to 1 to elevation 2760, and 2 to 1 to elevation 2793

River Outlets

Outlets: Two
Invert: Elevation 2710.00
Gates: Four, 6 by 7.5 feet (two are in-

stalled in each outlet)
Discharge capacity: 1,000 second-feet
with reservoir water surface eleva-
tion at 2720.0

Canal Outlet Works
Intake structure:

Vertical shaft: 50 feet high

Sill elevation: 2710.00
Outlet conduit: 5 feet 6 inches in diam-

eter, 208 feet long
Outlet pipe: 56-inch-diameter pipe in

horseshoe conduit, 244 feet long Gates: Two, 4 by 4 feet (one is in

stalled in the emergency gate chamber and the other in the control house) Discharge capacity: 300 second-feet

with reservoir water surface elevation 2720.0, and canal water elevation 2705.0

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October 1, 1953

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