The Merrimack River Crossing in Manchester, New Hampshire, created a vital component of the City’s water distribution system. The project included construction of nearly 5,000 feet of 20-inch water main for the City’s water utility, Manchester Water Works.
The project involved crossing the Merrimack River and an adjacent active railroad line in an environmentally sensitive area. Crossing the railroad required installation of a 42-inch steel sleeve below the railroad by means of pipe ramming, and then guiding the horizontal direction drill through the sleeve and under the river in one operation. The total length of the horizontal directional drilled river crossing is 900 feet.
Kleinfelder designed and oversaw the horizontal directional drilling component of the project, which involved several elements unique to the New England region. This included: horizontal direction drilling to install a 20-inch diameter fusible PVC pipe; variable subsurface conditions, such as bedrock; surface topography and features that minimized feasible alignment options; and the active railroad crossing.
Kleinfelder delivered innovative, timely, and cost-efficient engineering services for this project, which provides a much-needed connection to “close the loop" between isolated segments of the water system on the west and east sides of the river. This connection is critical for improving water pressure, enhancing water quality, and improving the overall level of service in this section of the distribution system.