Dam Removal Underway at Tyler State Park: Pennsylvania’s Second-Largest Dam Removal Reconnects Neshaminy Creek

Construction is now underway to remove the Spring Garden Dam on Neshaminy Creek in Bucks County, Pennsylvania’s Tyler State Park, marking a major milestone for river restoration efforts across the Commonwealth. At approximately 225 feet wide and 9 feet tall, the structure will become the second-largest dam ever removed in Pennsylvania.

Originally constructed around 1819, the dam was built to power the nearby Spring Garden Mill, creating a mill pond and directing water through a mill race to drive grain-milling operations along Neshaminy Creek. For generations, the dam supported an important piece of the region’s agricultural and industrial history.

Today, however, its original purpose has long since faded, and attention has turned to restoring the creek’s natural flow and ecological function. The dam removal will restore river connectivity and fish passage, improve aquatic habitat, enhance public safety, and create new opportunities for recreation.

With construction underway, the project has garnered media attention across the region, including recent coverage from NPR’s WHYY, which highlights both the benefits of restoring a free-flowing Neshaminy Creek and the Commonwealth’s leadership in dam removal. According to the report, Pennsylvania has removed more than 430 dams since 1912, making it the nation’s leader in dam removals.

Click here to read (or listen to) the full story.

Princeton Hydro’s Role in the Project

While the removal itself is making headlines today, projects of this scale often require years of scientific investigation and planning before construction can begin.

In 2023, Princeton Hydro was retained by the Commonwealth of Pennsylvania to conduct a comprehensive sediment impact assessment for the proposed removal of Spring Garden Dam. The study quantified the volume and characteristics of sediment stored within the impoundment, evaluated channel conditions upstream and downstream of the dam, and assessed how Neshaminy Creek could adjust following restoration of free-flowing conditions. The resulting analyses provided project stakeholders with critical technical information to support environmental review, regulatory coordination, sediment management planning, and project design.

The sediment impact assessment included:

• Detailed bathymetric mapping of the impoundment
• Sediment thickness and volume calculations
• Sediment sampling and grain-size characterization
• Longitudinal stream profile surveys upstream and downstream of the dam
• Evaluation of anticipated channel adjustments following removal
• Habitat assessments to support environmental review efforts

These photos below were taken as part of the pebble count analysis, which is a field survey technique used to understand the composition of a stream channel. By measuring and categorizing sediment particles throughout a stream reach, streambed composition can be characterized across a range of materials, from fine sand and silt to gravel, cobbles, boulders, and bedrock.

The removal of Spring Garden Dam marks an important milestone in the ongoing restoration of Pennsylvania’s waterways. Princeton Hydro is proud to have supported the Commonwealth of Pennsylvania during the planning and assessment phase of this historic project and looks forward to seeing the long-term recreational and ecological benefits take shape as Neshaminy Creek once again flows freely through Tyler State Park.

To read about our work to remove the largest dam in New Jersey’s history, click here.

• Dam and Barrier
• Stream Restoration