Historic Bridges

Red Rock Lake bridge

Marion County

Bridge information

Year constructed: 1965
Bridge type: Steel Continuous Welded I-Girder w/Floorbeams (2 Girders)
Length: 5653 feet
National Register of Historic Places status: Eligible
Width: 36 feet
Spans: 42
FHWA: 035200
Jurisdiction: Iowa DOT
Location: Iowa 14 over the Des Moines River (Red Rock Lake resevoir) north of Knoxville, 1.2 miles north of SR G40, Section 1, T76N-R20W & Section 36, T77N-R20W (Red Rock Township)


The bridge was designed by the Iowa Highway Commission. The contract for the 42-pier substructure of the over one-mile long bridge was let to Schmidt Construction Company of Winfield, Iowa in October 1963. The contract for the superstructure was let in April 1964 to Schmidt Construction Company. The substructure was completed in September 1964. The bridge was opened to traffic on November 4, 1965. The total cost of the bridge was $2,400,600 and was financed by federal funds as part of the $83 million Red Rock dam and reservoir project. (New Paragraph) The Red Rock Lake Bridge is eligible for inclusion in the NRHP under Criterion C as it does meet registration requirements outlined in the MPD as it is a continuous welded I-girder bridge with an exceptional length of over 2,000'. With an overall length of 5653', this bridge does meet that requirement. The Red Rock Lake Bridge does meet registration requirements under Criterion A for its association with the major federal undertaking of the construction of the Red Rock Dam and Reservoir. Though, the bridge is less than 50 years of age, it does possess characteristics of exceptional importance and thus does meet Criteria Consideration G. The Red Rock dam and reservoir project was one of the largest undertakings of its kind in Iowa and the Red Rock Lake Bridge was the longest and tallest bridge in Iowa at the time of its construction.

The Red Rock Dam project was authorized in the Flood Control Acts of June 1938 and December 1944. In June 1944, the Senate Commerce Committee approved $15 million of the $1 billion national flood control program for a large dam to the southeast of Des Moines (Council Bluffs Nonpareil June 25, 1944:7). Floods in 1947 prompted a second dam on the Des Moines River at Saylorville (Pella Chronicle July 19, 1956:1). In 1956, planning for the project began. On June 4, 1960, the groundbreaking ceremony was held. Approximately 86 miles of railroad, 10 miles of state highway, 85 miles of county roads, and numerous bridges in the area would be impacted, either through submersion or relocation (Pella Chronicle-Advertiser September 3, 1969:9B). Thus, while the dam was being built, several new bridges and roads were constructed. The 5,653' Iowa 14 Bridge over the Des Moines River / Red Rock Lake (FHWA #35200) was designed by the ISHC and opened to traffic on November 4, 1965. The total cost of the bridge was $2,400,600. The concrete road over the spillway and dam (FHWA #240385) was one of the last items constructed in 1967 (Pella Chronicle-Advertiser January 30, 1968:1). The IA 316 Bridge (FHWA #280555) between Runnells and Swan was completed in 1968. New bridges also had to be built for relocated routes such as IA 5 southwest of Knoxville. On March 17, 1969, the dam went into operation and the permanent pool level of 725’ was reached in three days due to the spring melt (Pella Chronicle-Advertiser September 3, 1969:Special Insert, p.7). The Red Rock Dam and Reservoir was dedicated on September 6, 1969. Four days of festivities accompanied the dedication of the dam. When completed, the 6,300-acre dam was the largest man-made lake in Iowa.


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