Rainbow Lake Dam

About Rainbow Lake Dam

The primary purpose of Rainbow Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Njdot (state). It impounds the Troy Brook near Deerfield.

The dam stands 20 feet tall and stretches 900 feet across, creates a reservoir covering 80 acres, has a storage capacity of 240 acre-feet, and collects water from a drainage area of 53 square miles. Completed in 1774, the structure is one of the older dams in the region, with over a century and a half of service.

This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 07/18/2023.

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