Lake Chillisquaque
Spillway Upgrade

The project will expand and deepen the spillway. It will also install a concrete drop structure within it. The project includes 3 key phases: excavation, construction of the concrete drop structure, and site remediation.

The updated spillway will slow the flow of water from the lake in the event of a significant rainfall event, which will improve its functionality and help minimize future erosion. The new structure will also extend the spillway’s longevity.

Talen, with oversight and approval from the PA Department of Environmental Protection (PADEP) and the Army Corps of Engineers, made repairs and improvements to the spillway after a significant rainfall event in 2018. In 2019, Talen, in conjunction with PADEP, began the modeling and analysis work needed to support this project. In 2022, Talen submitted a dam safety permit modification request to PADEP to rehabilitate and improve the spillway. Talen received permit approval from PADEP in December 2025 and immediately began an RFP process for the project.

Construction is expected to start in the spring of 2026 and last approximately 12-18 months.

The project will consist of three major phases:

1. Excavation – The spillway will be expanded and deepened to accommodate a roller compacted concrete (RCC) drop structure and stilling basin. During the excavation phase of the project, it will be necessary to use controlled, low-level blasts to loosen and remove select sections of rock below the surface of the existing spillway channel. This is a common construction practice, and experienced contractors will follow a comprehensive plan to safely complete this work. The activity is expected to occur once a week for a handful of weeks in early to late summer, with the blast itself taking only a few minutes. Engineers have compared the magnitude of the blasting, which is only expected to be felt in close proximity to the site, to a large truck driving down a two-lane road.

   As a safety precaution, access to sections of the Montour Preserve will be limited for a short period of time just prior to and following each event.  Traffic on adjacent roadways will also be halted while blasts take place.

   Notifications will be sent to neighbors, posted on the project website, and shared on social media well in advance of any scheduled blasting, and every effort will be made to minimize the impact to visitors and neighbors.

2. Drop Structure Construction – Following excavation, a roller compacted concrete (RCC) drop structure will be constructed on site, and a stilling basin will be installed within the existing auxiliary spillway channel to safely convey spillway discharges.
3. Site Restoration – Final grading will be completed during this phase and disturbed areas will be restored with grass, which is the preferred cover to support inspections and observe deficiencies. Grass cover will support permanent stabilization of the site.

Minimal disruptions could temporarily impact amenities at the Montour Preserve during certain phases of the project. Those include access to the pavilions, a portion of the Chilisuagi trail, and the boat launch. We are working closely with MARC and other stakeholders to communicate with the community in advance of these temporary disruptions. We will also post information on our website. Please continue to check this website and/or sign up for project updates.

Updates about the project will be posted on this website. You can also sign up to receive updates using the form on our site. The Montour Area Recreation Commission and other local stakeholders will also share key updates on their social channels.