Undersized culverts found to be a main source of Wood-Pawcatuck flooding

By Judy Benson, Day staff writer

Richmond, R.I. — Nearly half of all the culverts in the watershed of the Wood and Pawcatuck rivers are too small to allow for adequate water flow during intense storms, contributing to the risk of flooding in the 317-square-mile area.

“We’re got a problem here,” said Erik Mas, vice president of the engineering firm Fuss & O’Neill, during a presentation Thursday to about 25 people at the H.L. Arnold Fire & Safety Complex. About 38 percent of the more than 400 culverts and bridges his firm inspected are undersized, and another 11 percent are expected to be undersized by the year 2070 as annual rainfall increases with climate change, he said.

The information about culverts and bridges was part of Mas’ presentation of findings of a study commissioned by the Wood-Pawcatuck Watershed Association of how to make the watershed less vulnerable to flooding. Funded by a $720,000 federal grant, the work began in 2015 and will result in creation of a plan for projects the 14 communities in the watershed can undertake to lessen damage from future floods like the one that occurred in 2010. Input from local officials and community residents at the meeting Thursday and another next week will be incorporated into Fuss & O’Neill’s final report, to be called the Wood-Pawcatuck Watershed Flood Resiliency Management Plan.

Denise Poyer, project coordinator for the watershed association, said a draft plan will be presented to the community in January, and a final plan issued in March. After that, the association will host training sessions for municipal officials about how to implement the recommendations of the plan and obtain funding for projects.

“It’s not just about culverts and dams,” she said, “but also about putting in green infrastructure projects.” Creating swales, wetlands and gardens to store water would help minimize flooding and improve water quality. The plan will also make recommendations for changes in town regulations to discourage building in flood plains, she said. In addition, it will identify areas where stream channels could be restored with their natural meanders to slow floodwaters, and provide preliminary engineering plans for proposed projects. In all, about 30 proposed “green infrastructure” projects throughout the watershed are described in the preliminary plan.

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