Watershed Ecology

Surbering & Flowmeter

The objectives of the Patrick Center’s Watershed Ecology Section are to understand, conserve and restore aquatic ecosystems through holistic analysis, and to make our science accessible to a broad audience. We collaborate with the other Patrick Center sections to evaluate multiple aspects of ecosystem structure and function, and to relate them to stressors from human activities. We are interested in how our studies and data can be used by conservation practitioners and everyday people to advocate for water quality around them. We are also committed to increasing the diversity of our team and the people served by our work through activities related to justice, equity, diversity and inclusion. We are inspired by the pioneering work of our founder, Dr. Ruth Patrick, as she laid the groundwork for women and other groups to make meaningful contributions in the environmental science fields. Our focus on analyzing aquatic macroinvertebrate communities (insects, snails, worms and others) continues her legacy to focus on what living creatures can tell us about the quality of an ecosystem. Through study design and statistical techniques, we work to parse out the main issues affecting stream health from multiple stressors, including agricultural and urban land use, stormwater, chemical pollution (including excess nutrient inputs from agriculture and wastewater) and other types of habitat degradation and ecosystem alteration.

Clear here to learn more about our staff.

Click here to visit our Macroinvertebrate Lab webpage.


  • Aquatic invertebrate sampling and analysis to genus
  • Multiple scale analyses of stream networks (microhabitat, reach, and watershed)
  • Use of diverse sampling and analysis methods to align with state and federal protocols, diversity studies, or research questions.


The Watershed Ecology Section builds upon The Academy’s diverse set of skills in systematics, ecology, engagement and education. We have access to a variety of sampling gear, vehicles, laboratory equipment, and other facilities to complete large, multidisciplinary studies.

  • Database of streams in the Delaware Basin at multiple scales
  • DRWI data, in collaboration with the Environmental Data Science and Biogeochemistry Sections.
  • Vehicles such as motor boats and trucks
  • Field sampling equipment for fish, macroinvertebrates, plankton, and epiphyton
  • Fisheries laboratory (fish identification, aging using scales or otoliths)
  • Library and collections of biota from Patrick Center projects throughout the country, spanning the past several decades
  • Collections in the Departments of the Diatom Herbarium, Entomology and Malacology
  • Sediment and water chemistry laboratories
  • Variety of microscopes and dissecting scopes

Selected Projects

Delaware River Watershed Initiative
P.I. -Stefanie Kroll, Ph.D.
The Delaware River Watershed Initiative (DRWI) is an unprecedented collaboration to protect and restore water quality in the Delaware River watershed. More than 50 leading nonprofits have joined together to accelerate conservation in eight regions of the watershed. Informed by science, the Initiative implements land protection and restoration projects in these eight ecologically significant areas. As the scientific lead for the DRWI, the Academy helps prioritize areas for on-the-ground work, designs and coordinates stream monitoring efforts at more than 300 sites throughout the watershed, and analyzes data to assess the impacts of DRWI protection and restoration projects on stream water quality.
The DRWI data collection allows us to work closely with on-the-ground conservation professionals to understand their objectives and needs for monitoring data. Our goal is to provide them with information they can use in outreach to government agencies, local decision-makers and other stakeholders within their communities. Our first years of data are now available in raw form on Hydroshare (CUAHSI database) for download. However, we know that most people want the data in a form that they can use to speak to diverse audiences, which is why we work one-on-one with our partners to develop small reports with interpretations. Requests can be made directly to Kathryn Christopher, at kac388@drexel.edu.
Assessment of Past Restoration Projects in Southeast PA, 2015 - 2018 – PA DEP Growing Greener
P.I. -Stefanie Kroll, Ph.D.
Stream restoration projects (streamside vegetation plantings, modified stormwater basins, stream fencing, stream channel modification, etc.) have been completed throughout the Delaware River watershed over the past 20 years, with a goal of improving aquatic habitat and/or water quality. From 2002 to 2006, Academy scientists studied the streams where these restoration projects had been implemented, using biological, chemical, and physical analyses to determine changes in aquatic habitat and water quality in relation to the completed project. The Watershed Ecology section builds on this study by surveying those previously-studied restoration project sites (now 12-20 years old), as well as sites restored more recently (5-10 years old). Results will be analyzed and applied to current and future restoration and monitoring efforts.
Assessing restoration outcomes in aquatic habitat and biotic communities in MD and PA – Maryland Sea Grant
P.I.s –Matthew Baker, Ph.D. (University of Maryland, Baltimore County) & Haley Oakland
Collaborator –Stefanie Kroll, Ph.D.

Utilizing preliminary outcomes from the Academy’s PA DEP Growing Greener project (Assessment of Past Restoration Projects in Southeast PA, 2015-2018), UMBC and the Academy’s Watershed Ecology section collaborate to study restoration projects in Pennsylvania and Maryland. While the restoration project assessments in Southeast PA take a close look at stream chemistry and biological communities (algae, fish, aquatic insects, etc.), this study combines those traditional assessments of aquatic habitat and biota with remote sensing techniques to attempt to improve the ability to measure changes in stream ecosystems, and understand relationships between biological communities and habitat post-restoration.
Wissahickon Valley Park – Habitat Management Plan
P.I.s – Will Ryan, Ph.D. & Richard Horwitz, Ph.D.
Friends of the Wissahickon has contracted the Academy of Natural Sciences to collaborate on creating the Wissahickon Valley Park (WVP) Habitat Management Plan. In 1999, the Fairmount Park Commission selected the Academy of Natural Sciences to work on the Natural Lands Restoration and Environmental Education Program (NLREEP), which resulted in the creation of the WVP Master Plan. We will evaluate gaps in data from the WVP, and identify, define and prescribe best management practices for ecological restoration and maintenance of ecosystem integrity, with special attention to locations in the park for which the actions are appropriate. In addition, we will describe appropriate monitoring techniques to quantify improvements in and/or maintenance of environmental conditions. Lastly, we will suggest research avenues that could further elucidate the complex ecological interactions present in the WVP.
Existing Conditions Report on Wissahickon Creek in the Whitemarsh Valley
P.I. – Will Ryan, Ph.D.
As the Wissahickon Creek flows through the limestone-rich Whitemarsh Valley, it passes through a culturally rich landscape, including Ft. Washington State Park, Erdenheim Farm, and Morris Arboretum. A number of stressors impact stream water quality (e.g., upstream impervious surfaces, obstructions, invasive species, and point-source pollutants) in this watershed. We have embarked on a multi-year project which aims to assess the current ecological and environmental conditions of the Creek. As we begin to analyze results, we will develop strategies to address local-scale factors, which, if dealt with, have the potential to ameliorate conditions in the Wissahickon Creek.
Lentic Habitats
P.I. - Stefanie Kroll, Ph.D.
Lentic habitats are areas in a stream with little to no flow. This study aims to assess possible relationships between agricultural land use, aquatic insect communities and habitat quality of these in-stream “pools” in agriculturally dense landscapes in the Schuylkill and Christina river watersheds. When studying aquatic insects for use as indicators of stream ecosystem integrity, samples are often only taken from riffle areas, because riffles typically display the greatest species diversity. In lentic areas, agricultural runoff that carries excess fertilizer into the streams may affect oxygen, sediment deposition, and temperature differently than in lotic (flowing) areas. In lentic habitats, we find taxa that are often absent in riffles, with a high percentage of predators and air-breathing species. We are also interested in whether watershed size plays a role in the relationships between habitat quality and community composition.