Nashua, located in Southern New Hampshire, is at the confluence of the Merrimack and Nashua Rivers, including Pennichuck Brook and Salmon Brook. Pennichuck Water Works, Inc., Nashua, developed the Pennichuck Brook Watershed Restoration Plan that addresses the area’s water quality concerns. A component of this restoration plan is an upgrade of the water treatment plant in Nashua. After researching the costs and benefits of available alternatives, Pennichuck specified an AWWA D110 Type III prestressed concrete water storage tank because of its cold climate performance and negligible maintenance requirements. Preload, a recognized innovator in the prestressed concrete tank industry, was selected as the preferred firm to construct the tank.
Built in 2005, this Preload clearwell holds up to 6.5 MG of treated water, and has an inside diameter of 192’ and a side water depth of 30’. Its dome roof can withstand heavy snow loads experienced in this region of the country. This durable dome design results in uniform compression throughout the dome shell, allowing relatively thin sections of concrete to span large tank diameters.