Dam and River Basin

Rathbun Lake was constructed and is operated by the U.S. Army Corps of Engineers. Located at Chariton River mile marker 142, approximately 7 miles north of Centerville Iowa, in Appanoose County, it is one of the largest lakes in Iowa. The lake was constructed to control flooding, provide recreation opportunities, abate stream pollution, fish and wildlife enhancement, and maintain minimum stream flow on the Chariton, Missouri, and Mississippi Rivers.

The Chariton and South Fork of the Chariton River are the major sources of water flowing into Rathbun Lake. The Chariton River Basin drains a total or 2,309 square miles, of which 549 square miles are located above the dam. The basin runs generally from north to south. The drainage area has a maximum width of 25 miles and an average width of 12 miles. Rathbun Lake has a flood control pool of 20,948 surface acres and a multipurpose pool of 11,013 surface acres. Rathbun Lake averages about one mile in width and has 155 miles of shoreline at the top of multipurpose pool elevation. At full pool elevation, the lake has 319 miles of shoreline and extends generally westward a distance of about 21 miles into Lucas, Wayne, and Monroe Counties.

The dam consists of a rolled earthfill embankment with an uncontrolled spillway located approximately 3,000 feet westward of the right abutment. Discharges enter a concrete stilling basin. Additional pertinent data is listed below:

Pertinent Data

Authorization: Flood Control Act of 1954 (Public Law 83-780)
Record near Damsite: 21,800 c.f.s. 31 March 1960
Channel Capacity: Initial damage 1,500 c.f.s.
Below dam: Appreciable damage 2,000 c.f.s.
Cost (Dam and Reservoir): $26,500,000 (1969)

Dam and Embankment

Type: Rolled earthfill
Fill Quantity: 5,500,000 cubic yards
Crest Elevation: 946.00
Top Width: 30 feet
Maximum Base Width: 800 feet
Length: 10,120 feet
Maximum Height above streambed: 100 feet
Freeboard: 5.8 feet
Closure Date: 29 December 1967
Storage Began : 21 November 1969
Multipurpose Level Reached: 10 October 1970

Reservior

Multipurpose pool: From elevation 844.0 to 904.0
Flood control pool: From elevation 904.0 to 926.0
Surcharge: From elevation 926 to 940.0
Multipurpose pool storage: 205,359 acre-feet
Flood control pool storage: 346,297 acre-feet
Surcharge storage: 349,514 acre-feet

Spillway

Type: Uncontrolled Notch
Crest Elevation: 926.0
Width: 500 feet
Discharge Capacity at Elevation 940: 45,600 c.f.s.
Side slopes: 1 on 3