Merrimack Water Main Crossing & Intake

Project Highlights

  • 2020 ACEC/NH Silver Award for Engineering Excellence
  • Horizontal Directional Drilling
  • Water System Expansion
  • Groundwater Trust Fund
  • State, Federal, Muncipal & Private Coordination
  • River Crossing Design Alternatives

Tighe & Bond Awarded for Helping to Create a Safe Public Water Supply

When PFAS contaminated more than 360 wells in Litchfield, New Hampshire, Pennichuck Water Works (PWW), a local water utility, needed a fast-tracked solution. Tighe & Bond was already under contract with PWW to design and provide construction administration services for a new 30 MGD in-river raw water intake on the Merrimack River next to Litchfield. Our firm shifted priorities and worked with multiple stakeholders, sub-consultants, and contractors on designing and constructing a new water main that would cross the Merrimack River and connect Litchfield to a safe public water supply.

After an extensive alternatives analysis, we recommended an open-cut, wet installation of the pipe into the riverbanks on each side of the Merrimack River and an armored pipe installed across the river bottom. This approach prevented safety risks, the costly risk of scheduling delays with directional drilling frac out, and minimized disruption to the environment.

In August 2018, 650 linear feet of HDPE pipe for the new water main was pulled across the Merrimack River. By October 2018, the full interconnection was substantially complete, and over 368 private wells in Litchfield were connected to the new water service. The completion of the project significantly improved service for the Town of Litchfield and the overall resiliency of the PWW distribution systems without disrupting pump station operations or water service for customers. After completing the river crossing water main, Tighe & Bond continued working on the raw water intake to provide a permanent redundant source and completed the project in spring 2020.

Our team was awarded a 2020 Silver Engineering Excellence Award from ACEC/NH for the team’s swift action and innovative solutions to a potential health crisis.

Services Snapshot

Tighe & Bond provided design and construction administration services for this project. Our work also included the development of alternatives analysis to compare and implement recommendations surrounding the new water main.

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