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Cocheco River Local Protection Project

Cocheco River, FarmingtonThe Cocheco River Local Protection Project in Farmington is located along the Cocheco River. The entire project protects about 45 acres of industrial, commercial, and residential property in the center of Farmington.

The limited channel capacity of the Cocheco River frequently caused the river to overflow, resulting in flood damage to the center of Farmington. The town suffered serious flood damage in March 1936 and May 1954. This limited channel capacity was aggravated by periodic ice jams. Cakes of ice that had lodged against obstructions in the river, such as debris and several small wooded sand bars and islands, plagued Farmington for many years and was the cause of most of the area’s flooding.

To increase the channel capacity of the Cocheco River, the Corps built a project on the upper part of river between the Central Street Bridge and the South Main Street Bridge. The work, constructed under Section 205 of the Continuing Authorities Program, was completed between June-November 1956 and cost $87,500. The project was turned over to Farmington for operation and maintenance.

In January 1957, however, ice cakes, flowing from the upper part of the Cocheco River between the Central Street and South Main Street bridges to the lower part of the river, below the South Main Street Bridge, lodged in the vicinity of Dames Brook, located about 2,000 feet below the South Main Street Bridge. The river overflowed and caused considerable flood damage to one of Farmington’s major industrial employers. Town officials, businessmen, and manufacturers, weary of the periodic ice jams that continually jeopardized their community, approached the Corps and emphasized the importance of a project that would extend to the lower part of the Cocheco River the same degree of protection afforded to the upper river by the existing project. The Corps responded by constructing a project on the lower river between June and November 1959 at a cost of $48,600. This work was also constructed as a small project under Section 205 of the Continuing Authorities Program, and was turned over to Farmington for operation and maintenance.

The entire project extends along a 7,800-foot-long stretch of the Cocheco River. It begins at the Central Street Bridge and ends at a point 4,700 feet downstream of the South Main Street Bridge.

Work completed on the upper part of the river centered mostly on the approximately 3,100 feet of river between the Central Street and South Main Street bridges. It involved constructing about 3,000 feet of earthfill dike along the left bank of the river. The dike, constructed of materials excavated from the channel, begins at a point about 200 feet downstream of the Central Street Bridge and ends at the South Main Street Bridge. Along the left bank of the river, approximately 125 feet of concrete floodwall, 10-12 feet high, was constructed. The wall extends from the existing masonry wall at the Central Street Bridge to the beginning of the earthfill dike. A concrete cap was constructed on the existing masonry wall to give the wall additional height, thereby providing an extra measure of flood protection. Also included was enlarging and straightening about 3,100 feet of the Cocheco River, straightening about 600 feet of the Mad River at its confluence with the Cocheco River, removing an abandoned wooden dam, and clearing and snagging about 2,000 feet of the Cocheco River. This work extended from the South Main Street Bridge to the mouth of Dames Brook.

Work completed on the lower part of the river, below the South Main Street Bridge, involved widening and deepening about 4,000 feet of the Cocheco River, beginning at the South Main Street Bridge and extending downstream; snagging and clearing an additional 700 feet of the Cocheco River, beginning at the point where the aforementioned widening and deepening ended; constructing 200 feet of earthfill dike with stone slope protection along the left bank, just downstream of the bridge from materials excavated from the channel and straightening and widening the lower end of Dames Brook, from the Elm Street Bridge to its confluence with the Cocheco River.

In the early 1960’s, the project suffered significant flood damage. Consequently, the Corps repaired and restored the project between September and December 1964. This work included widening and reshaping the channel; constructing stone slope protection at areas subject to severe erosion; and constructing a deflecting stone groin at the confluence of the Mad and Cocheco rivers. The work was completed under Section 205 of the Continuing Authorities Program and cost $47,000.

In April 1984, heavy flooding significantly eroded two sections of the 3,000-foot-long dike on the upper part of the river. Emergency repairs included placing stone slope protection along these eroded areas and repairing a drain pipe. This work, constructed under the Corps’ emergency repairs authority (Public Law 99 of the Flood Control Act of 1941), was accomplished between September and October 1985 and cost $137,000.