Celebrating Progress on Tredyffrin Township’s Upper Weadley Stormwater Improvement Project

On July 16, Pennsylvania State Senator Carolyn Comitta joined municipal leaders, project partners, and community residents in Tredyffrin Township to celebrate the progress of the Willis Lake, Woodcrest Road, and Upper Weadley Road Stormwater Improvement Project, a significant initiative designed to reduce flooding, modernize aging infrastructure, and improve water quality within the Upper Weadley tributary, which feeds into Trout Creek and ultimately flows into the Schuylkill River.

Tredyffrin Township Engineer Steve Burgo, PE, led participants on a guided site tour that showcased key construction milestones and recently completed improvements, and provided a deeper look into the long-term stormwater management benefits the project provides to community residents, local water resources, and the watershed as a whole.

Tredyffrin Township has worked closely with Princeton Hydro since 2012 through an ongoing on-call engineering services partnership. Over the past decade, this partnership has supported watershed assessments, stormwater planning, identification and prioritization of improvement projects, grant funding efforts, and the implementation of practical, science-based solutions to address flooding, improve watershed health, and strengthen community resilience. The collaboration has also extended to numerous municipal infrastructure initiatives and major residential, commercial, and institutional redevelopment projects throughout the Township.

The Willis/Woodcrest/Upper Weadley project, which began in 2022, represents an important milestone in Tredyffrin Township’s ongoing efforts to address persistent stormwater management and flooding challenges. The planning process began with a comprehensive evaluation of the approximately 70-acre watershed. Princeton Hydro developed a hydrologic model of the watershed and its existing stormwater system using field survey data, Township records, and other site-specific information. This analysis helped identify critical areas where aging infrastructure and system limitations were contributing to localized flooding and drainage issues.

Community engagement also played a key role in shaping the project. Township officials and Princeton Hydro hosted public meetings with residents to gather local knowledge, document firsthand experiences with flooding, and discuss potential solutions. This input provided valuable insight into how stormwater impacts neighborhoods during major storm events and helped inform project priorities.

Combining technical analysis with community feedback, the project team evaluated a range of potential improvements, including both traditional “gray” infrastructure upgrades and nature-based “green” stormwater management strategies. The solution incorporates a series of targeted improvements that work together to reduce peak stormwater flows, increase storage and infiltration, modernize aging infrastructure, and improve the overall performance and resiliency of the watershed.

The final design combines critical upgrades to aging drainage infrastructure with new stormwater management measures that work together to better capture, convey, store, and infiltrate runoff throughout the watershed. Construction is anticipated to be completed later this year. The project is being funding from several funding sources, including the Pennsylvania Department of Community & Economic Development (DCED) H2O PA – Water Supply, Sanitary Sewer and Storm Water Projects Program, which supports critical water infrastructure investments throughout the Commonwealth.

Key project improvements include:

• New and upgraded stormwater piping, inlets, and manholes
• Construction of a new above-ground stormwater management basin
• Installation of underground stormwater infiltration facilities
• Modernization of aging drainage infrastructure
• Improvements designed to reduce peak stormwater flows and mitigate downstream flooding impacts
• Construction of a stormwater basin designed to capture and manage runoff from upstream portions of the watershed
• Installation of 160 native trees and 90 shrubs to stabilize the basin and surrounding area as well as providing screening. The new plantings also replaced trees that had deteriorated and were in poor health.
• Lining of the sanitary sewer pipe network within the project area further providing infrastructure upgrades and improvements.

One of the most compelling aspects of this project is the visible transformation that has occurred across the project site. The before-and-after photos below highlight the significant being progress made to address longstanding drainage challenges and improve stormwater management throughout the project area.

Before Construction:

After Construction:

Before Construction:

After Construction:

Before Construction:

After Construction:

These additional pre-construction photos taken in 2023 document the conditions that prompted the project, including aging drainage infrastructure, erosion, and areas impacted by repeated stormwater flooding.

Today, as the construction work continues, the results of these improvements are already clearly visible throughout the project area. Modern stormwater infrastructure, enhanced drainage capacity, and thoughtfully integrated stormwater management features have transformed the site into a more resilient landscape capable of better managing runoff and reducing flood risk.

Princeton Hydro is honored to partner with Tredyffrin Township and support their continued leadership in and commitment to stormwater management. Please stay tuned for more updates later this year once construction is complete!

To learn more about this project, click here. To learn more about our work in Tredyffrin Township, click here.

• Landscape Architecture
• Flood Mitigation
• Natural Resource Management
• Stormwater Management