New York

Improving Culverts

See how we're improving culverts to make river and stream crossings work better for local communities and wildlife.

Roaring Brook culvert prior to replacement: At lower flows this culvert outlet was perched above the water surface, creating a barrier to the movement of fish. The stream was constricted by the pipes’ combined span of 12 feet, which caused debris build-up and localized flooding.

Roaring Brook culvert replacement: With a width of 35 feet, the new culvert – an open-bottom concrete box with a natural streambed – allows the stream to pass freely underneath, opening six miles of upstream habitat for fish and designed to withstand high water flows.

Prior to construction, U.S. Fish & Wildlife technicians inventory fish on the downstream side of the culvert. Afterward, on the upstream side, they check to see if any fish they marked have moved through the new culvert.

The outlet drop here is too large for most aquatic species to jump, and the water is moving too quickly for them to swim.

A carefully designed step pool system raised the streambed to eliminate the drop and restore fish passage, while maintaining the natural slope of the stream and supporting a more natural flow of water and sediment.

In 2015, the Conservancy’s Adirondack Chapter worked with partners on three high priority culvert replacement projects. Not only do these demonstration sites improve fish passage and bolster resiliency, each now serves as a model for similar work.

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