On scenic Peirce Island, where the earthen remains of Fort Washington hearken back to the Revolutionary War and the War of 1812, building the largest public works project in Portsmouth, N.H., history required close coordination from Day 1.

Crews tasked with upgrading the Portsmouth Wastewater Treatment Plant on the banks of the Piscataqua River in the same footprint as the existing plant had to maintain wastewater treatment operations and public pool access. The project team, led by Plaistow, N.H.-based Methuen Construction, also had to manage traffic flow and deliveries on a single access road to the rocky 27-acre historic island.