For over 120 years, the York Haven Hydroelectric Station Dam stood across the Susquehanna River, generating power for surrounding communities. But it also prevented American shad and blueback herring from migrating to their historic spawning grounds in upstate Pennsylvania and New York.
As the deadline to renew the dam’s operating permit approached, so did the opportunity to reconnect these fish with their spawning grounds. Flyway Excavating partnered with Eagle Creek Renewable Energy in 2024 to construct the York Haven Fishway, an inland bypass around the dam and a critical environmental restoration project.
Project Goals
- Restore fish passage around the York Haven Dam by constructing a nature-like fishway.
- Complete the fishway without interrupting the dam’s operation and in time to renew its operating permit.
Flyway’s Involvement
Flyway served as the prime contractor for building the nature-like fishway, only the second of its kind in Pennsylvania. Designed to mimic a natural waterway, it provides an open channel that allows fish to bypass obstacles such as dams.
The project required coordination among multiple agencies, including the Federal Energy Regulatory Commission (FERC), the Pennsylvania Department of Environmental Protection, Division of Dam Safety (PADEP Dam Safety), the Pennsylvania Fish and Boat Commission, the Dauphin County Conservation District, and the Delaware Nation.
Construction took place at the southern tip of Three Mile Island in Dauphin County, with a scope of work that included:
- Clearing more than 22 acres of the project site
- Installing two temporary cofferdams for water control, including 370 linear feet of sheetpiling, 230 concrete blocks, and more than 10,000 cubic yards of rock
- Excavating approximately 55,000 cubic yards of soil
- Removing a 90-foot section of the existing dam to create a cascade to draw fish to the entrance of the fishway
- Constructing a 385-foot cutoff subsurface wall and 130-foot concrete fishway weir
- Creating 11 rock weirs using more than 7,400 tons of limestone boulders
- Installing 8,400 tons of riprap to prevent stream bank erosion
- Planting 15 acres with native meadow and forest grasses and 3,400 trees and shrubs
The Result
At 120 feet wide and 750 feet long, the York Haven Fishway runs through the southern end of Three Mile Island and provides a way for fish to bypass the dam that had cut off their migration route. Flyway also planted thousands of native trees, shrubs, and grasses surrounding the fishway, restoring 15 acres of natural habitat for other species.
The project was completed over 15 months and finished within one week of the planned schedule without interrupting the York Haven Dam’s operation. When field conditions revealed that portions of the original design could not be constructed as planned, Flyway worked with the project team to develop innovative alternatives that reduced construction time, lowered costs by $1.1 million, and maintained the project’s environmental goals.
With the completion of the York Haven Fishway, Eagle Creek Renewable Energy secured its permit to continue operating the dam, and the American shad and blueback herring are once again able to navigate the Susquehanna River northward to their ancestral spawning riverbeds.