Stabilizing the Gully: A Step Pool Solution for Stormwater Erosion in Historic Oella, Maryland

Brief Description

The Oella Homeowners Association, a historic mill community in Baltimore County, Maryland, is working to stop an eroding gully that carries stormwater off Charles James Circle and threatens nearby roads, private property, and water quality in the Patapsco River. This project aims to design a step pool conveyance system that slows runoff, stabilizes the gully, and reduces the sediment reaching the Chesapeake Bay. The community is seeking a scientist or engineer to help confirm the design approach, prioritize among several eroding sites, and prepare the plan needed to pursue funding and construction. The result will be a practical, buildable plan that protects the neighborhood and the watershed.

Description

About the Community

Oella is a historic mill town in Baltimore County, Maryland, situated along the Patapsco River within the Patapsco River watershed. Industry shaped the community from the early nineteenth century, and its nineteenth-century workers’ houses and former mill complex earned the Oella Historic District a place on the National Register of Historic Places in 1976. Today the neighborhood is represented by the Oella Homeowners Association (HOA), which owns about 19 of the roughly 46 acres that make up the community, with the remainder in private ownership. Steep hills and an aging storm drain system leave the community with high flows, nuisance flooding, and soil erosion during rain events.

In 2021 the HOA worked with the Center for Watershed Protection to complete a Stormwater Assessment and Action Plan that documented eight problem sites and recommended practical improvements. The HOA’s priority now is to move from assessment to action on the erosion problems that most threaten roads and property, starting with the gully near Charles James Circle. Several members bring relevant experience, including a community lead with a long background in disaster response, and the HOA is partnering with Thriving Earth Exchange to add the technical expertise needed to design and prioritize solutions.

About the Project

This project focuses on the eroding gully at Site 3, near the overflow parking lot off Charles James Circle. Stormwater from the parking lot and surrounding lawns collects in a catch basin about 12 feet deep and discharges through a pipe into the woods, where the flow has cut a gully that continues to erode down toward a neighboring church parking lot. Part of the gully sits on HOA land and part on church property, and the erosion has already produced a sinkhole and repeated flooding downhill. The 2021 stormwater plan recommends a stormwater step pool conveyance system (SPCS) for this site. This is an open channel of pools and riffles built from cobble and stone that slows the water, lets it soak into the ground, stabilizes the side slopes, and filters sediment before it reaches the Patapsco River and the Chesapeake Bay.

The project will produce a refined, buildable design concept for the step pool system, along with a clear sense of how the Site 3 gully compares in urgency to other eroding sites in the community, such as the roadway gully near Charles James Circle above Logtown Road. With a scientist or engineer on the team, the HOA will confirm the feasibility of the recommended approach, identify the data still needed for design, and prepare the documentation required to pursue grant funding and permits. When the work is complete, the community will have a practical plan to reduce erosion, protect its roads and homes, and improve water quality downstream. The project will also give a small, volunteer-run HOA a repeatable model for addressing the remaining gullies that affect the neighborhood.

Timeline and Milestones

The team expects the following milestones, to be refined once a scientist joins the project:

•  Scope finalization and publication of the project page on the Thriving Earth Exchange website

•  Recruitment and onboarding of a scientist or engineer with stormwater and erosion expertise

•  Review of existing studies (2021 Oella Stormwater Assessment and Action Plan and 2012 Baltimore County Lower Patapsco River Small Watershed Action Plan) and identification of any additional site data needed

•  Creation of a refined design concept and feasibility assessment for the Site 3 step pool conveyance system

•  Prioritization of the gully sites and a recommended sequence for future work

•  Host a community meeting to share findings and next steps

•  Develop a summary of options for funding, permitting, and construction

•  Develop a summary of project results and share potential solutions to the broader community experiencing the same issue

Project Team

Community Leads

Winnie Carpenter is a community lead for the project and a 22-year resident of Oella. She brings extensive experience with the Federal Emergency Management Agency (FEMA), including numerous deployments for water-related disasters, and has helped bring the gully erosion problem to the HOA and to Thriving Earth Exchange. As a Member-at-large with the HOA, she hopes that completing the gully project will lead to the mitigation of additional flood-prone sites in her neighborhood. 

Amanda Reardon is a community lead who supports the project with a background in emergency management and transportation incident management, including coordination as well as facilitation of communication between Federal, State and local jurisdictions. She additionally sits on the Oella HOA as Vice President. She absolutely loves Oella and am looking forward to the process and completion of our submitted gully project. It is just one more way to help our neighbors and better our community.

Community Science Fellow

Jan Philip de Leon (he/him) is the Community Science Fellow supporting this project through Thriving Earth Exchange. He is a PhD student in geography and spatial sciences at the University of Delaware and a licensed civil engineer whose research focuses on hydrology and flooding, including community flooding studies in Lewes, Delaware. As a Fellow, he will help the community define a workable project, connect the team with a volunteer scientist, and guide the effort toward a feasible outcome.

Scientist Wanted

Scientist Role

The team is looking for a scientist or engineer with experience in stormwater management and stream or gully restoration to help move the Site 3 gully from assessment to a buildable design. The scientist will review the 2021 stormwater plan and current site conditions, confirm whether a step pool conveyance system is the right fit, identify any additional data or field measurements needed, and help prepare a design concept and rough cost estimate that the HOA can use to pursue funding and permits. The scientist will also help the community compare the gully sites and decide where to act first. This is a pro bono, volunteer role suited to a few hours a month over roughly 12 months, not a full-time commitment. The team would welcome a scientist who can visit the site in person, though much of the work can be done remotely. A local environmental scientist has expressed interest and may take part alongside the matched expert.

Desired Skills and Qualifications

•  Background in civil or environmental engineering, hydrology, or geomorphology

•  Experience with stormwater conveyance, erosion control, or stream restoration (step pool conveyance systems)

•  Familiarity with green infrastructure and water quality practices

•  Ability to translate technical findings into plain language for a volunteer community group

•  Strong listening and collaboration skills

•  Willingness to work with a small, volunteer-run homeowners association

•  Able to visit the community in person when needed

Thriving Earth Exchange asks all scientific partners to work with the community to help define a project with concrete local impact to which they can contribute as pro-bono volunteers and collaborators. This work can also position the scientists and communities to seek additional funding, together, for the next stage. Unsure if you’re the right fit for this project? Reach out to us via email at [email protected] to learn more. 

Interested in volunteering as a scientist? Apply now!