More than 8 inches of rain fell on the Pawtuxet River watershed during spring 2010. Add that to 11 inches that had fallen over the previous 35 days and central Rhode Island's urban impervious surfaces and you have a recipe for historic flooding: at 20.8 feet, about 6.3 feet over the previous record. The Pawtuxet River Stabilization Project reconstructed failed infrastructure that protects two historic mill buildings.
The existing challenge was to combat erosion along the river. A potential future challenge was storm intensification due to climate change. To ensure the reconstruction would withstand environmentally driven stress, an innovative two-tier system was deployed.
Stone arch weirs and stream barbs in the river control elevation changes, reduce velocities within the river, and direct erosive velocities away from critical infrastructure and into the center of the river. These also improved habitat value because they were constructed using natural rock to provide shelter for fish and other aquatic organisms.
Articulated concrete mats overlain by river stone filled with soil also guard against scour and provide habitat value. The lower articulated concrete matting layer serves as extra protection against extreme events along critical sections of the river.
Prefabricated walls were used along the river to reduce overall project costs. Additionally, a control system was built to make segments of the river dry for construction and then flipped to the other side of the river to make that part of the river dry for construction.
The solution earned the American Public Works Association (APWA) 2017 Public Works Project of the Year award in the Small Cities/Rural Communities – Disaster/Emergency category. This award honors agencies that demonstrate creativity, ingenuity, and efficiency in delivering projects that profoundly impact communities with 75,000 or fewer people. The winning team: Town of Coventry, R.I., and U.S. Department of Agriculture Natural Resources Conservation Service (managing agency); Cardi Corp. (primary contractor); and Fuss & O’Neill Inc. (primary consultant).
