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Ellwood Water Treatment Plant Design

Overcoming site challenges allows cutting-edge facility to be built at an optimal location near two waterways.
  • Aerial view of construction to install two tunnels between Beaver River and railroad tracks - Gannett Fleming.

    The installation of two 520-foot long bores accessed the raw water supply at the Beaver River.

  • View of the inside of a deep caisson - Gannett Fleming.

    The construction of a 160-foot-deep caisson was essential to project success.

  • Microtunneling machine ready to bore - Gannett Fleming.

    The caisson enabled microtunneling, which reduced site disruption and achieved railroad crossings.

Client
Pennsylvania American Water

Partner(s)
Buchart Horn

Location
Lawrence County, Pennsylvania

Our Role
Design, Engineering Services.

Data
Size
8 mgd (expandable to 16 mgd)
Construction Cost
$50 million
Completed
2019
Type
New Construction
Outcomes
  • Improved service reliability for 18,000 water customers
  • System capacity increased by 60%, with room for further expansion
  • Maximized protection of raw water supply by using two sources.

To increase drinking water system capacity and improve service reliability for approximately 18,000 customers in the Ellwood City area, Pennsylvania American Water (PAW) made its largest infrastructure investment ever in northwestern Pennsylvania. The $50-million Ellwood Water Treatment Plant and raw water intake/pumping facilities in Lawrence County replace a 100-year-old facility, bringing it into the modern era.

The new plant is located at the confluence of the Beaver River and Connoquenessing Creek to provide adequate supply and the added reliability of two raw water sources. Whereas the previous plant’s capacity was 5 mgd, the new plant features an 8 mgd raw water pump station (RWPS), expandable to 16 mgd. Gannett Fleming provided engineering services for the preliminary and final design and permitting of the plant’s intakes and RWPS. The investment in new infrastructure is already paying dividends—the plant is efficiently delivering high-quality drinking water to sustain the local community.

What We Did

Our firm verified the constructability of the plant’s planned submerged intakes by conducting an extensive stream survey of the confluence area, including 500 feet upstream into the rivers. Installing temporary intakes enabled the team to extract monthly two-year samples for testing at the proposed intake depth before construction began, ensuring that the source water would meet or exceed state requirements.

Because the RWPS is located at the top of a steep embankment, with two railroad tracks between it and the Beaver River intake, construction of a 30-foot-diameter, 160-foot-deep caisson was required. The structure served as a launching site for a microtunneling machine and facilitated the installation of vertical turbine pumps to supply raw water to the plant. Microtunneling was used to install 60- and 75-inch bores, each approximately 520 feet long, from the bottom of the caisson to the riverbank. A second 75-inch bore was installed across a third set of tracks and a designated archeologically sensitive area to an intake location on the Connoquenessing Creek. The process allowed tunnels to cross the tracks, avoid sensitive areas, and significantly reduce site disruption. Because of the project’s multiple railroad crossings, careful coordination with railroad companies and a conservation society was essential to successful delivery.

Key Features

  • Preconstruction testing ensured that the proposed sites of wedge-wire intakes would provide quality source water
  • Deep caisson construction created a launching site for a microtunneling machine and facilitated the installation of turbine pumps
  • Microtunneling enabled bore installation with minimal site disruption and no impacts to archaeologically sensitive areas
  • Extensive coordination with railroads facilitated permitting for necessary track crossings.

Awards & Recognition

  • Honorable Mention, New Installations, 2019, Trenchless Technology, Projects of the Year
  • Top Project Award, 2018, Water & Wastes Digest, Projects of the Year

Similar Projects: Water/Wastewater: Drinking Water, Engineering, Environmental Management & Remediation, Geotechnical, Environmental Management & Remediation: Permitting, Geotechnical: Site Evaluation, Drinking Water: Water Treatment Plants, Water/Wastewater, Engineering: Water/Wastewater