By Lauren McGrath, Director of Watershed Protection Program, Anna Walsh, Conservation Data and
GIS Specialist and Sarah Barker, Watershed Program Technician
The Darby and Cobbs Creek Community Science Program (DCCCS) was established in 2021 by the Darby Creek Valley Association and Willistown Conservation Trust with technical support from Stroud Water Research Center. While the initial goal of this collaborative project was to supplement the existing water chemistry data set collected by WCT Watershed Protection Program staff in Ridley, Crum, and Darby Creeks, this program has evolved into much more. DCCCS aims to create a network of training and mentoring opportunities to empower the residents and neighbors of Darby and Cobbs Creek watersheds to collect high quality environmental data and become advocates for healthy water in their communities. Detailed monitoring data also helps to identify pollution sources and areas of the landscape that pose a risk to watershed health and integrity.
At the time of publication of this article, the DCCCS program has 37 active sites across the Darby and Cobbs watershed. Each site has a dedicated volunteer who goes out every four weeks to collect data. In a watershed that is home to over half a million people, it is crucial to understand the relationship between human activity on the landscape and the function of these waterways. The data collection efforts of DCCCS volunteers have been making great strides towards aiding that understanding.
The network of DCCCS volunteers has captured the influence of overapplication of road salts and other contaminants on the landscape, as well as the impact of climate-related issues such as the severe drought during the fall of 2024. Additionally, the discovery of sensitive wildlife by volunteers is particularly notable. In 2024, a large bed of breeding freshwater mussels was documented as a result of volunteer sampling and exploration. Over the summer, the Watershed Team, led by Dr. Erik Silldorff of the Delaware RiverKeeper Network, and supported by community volunteers and students, completed a second year of freshwater mussel surveys in the headwaters of Darby Creek. To date, over 1,000 mussels (including two species) have been identified! This incredible community science discovery was shared at the Ecological Society of America conference in Baltimore, MD this past August.
The DCCCS website has also acquired a brand new time-slider tool to visualize the data collected by volunteers. Every month, when volunteers upload their data to the DCCCS portal, it is added to the website, where it is publicly accessible. Now, each site can be observed both in comparison to other sites within the study area, as well as how it changes over time, allowing you to watch how each winter’s salt application ahead of winter storms influences the water chemistry at every site. The relationship between land use type and water quality data is complicated, but several trends have become apparent in the data set: as impervious surfaces increase, so do the negative impacts on water quality. However, as forest cover increases, regardless of impervious surfaces, water quality improves.
These patterns are best reflected in water temperature, conductivity (water’s ability to transmit electricity as a result of dissolving minerals and contaminants from the surrounding environment), and chloride (primarily an indicator of road salt) data. This means that where there is more undeveloped open space, as is found in the northern portions of the watershed, planting more native trees and shrubs along the stream can support healthier waterways. In the sections of Darby and Cobbs Creek closer to Philadelphia, where undeveloped open space is limited, actions like reducing the amount of road salt applied to the landscape and sweeping up road salt after winter storms, may be more impactful. The key to a healthier watershed lies in the collaboration between individuals, organizations, and municipalities across the Darby and Cobbs watershed, from the headwaters all the way to John Heinz National Wildlife Refuge. Visit the website, darbycreekcommunityscience.com, to see the data from the DCCCS program, and check out the new edition of the State of Our Streams Report to learn more about the relationship between land and water!
The critical work of the DCCCS Program volunteers was recognized through a grant from the Pennsylvania Department of Environmental Protection Environmental Education Grants Program. The award will support the continued education and empowerment of the Darby and Cobbs Creek communities, and highlight the data collected by the DCCCS program, what it means, what questions are raised, and actionable steps participants can take to positively affect the health of their local waterways. Three workshops across Chester and Delaware Counties are being scheduled for early spring 2026.
