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Gwynns Falls Watershed

Watershed Management Program
Phone: 410-887-5683
Fax: 410-887-4804


This is a map showing the location of the Gwynns Falls watershed.

Located in the southwestern portion of Baltimore County, the Gwynns Falls Watershed extends from Reisterstown to Owings Mills. The lower third of the watershed continues into Baltimore City and includes the communities of Dickeyville, Franklintown and Rosemont. The 66 square mile watershed (City and County combined) contains 133 miles of streams and drains to the Middle Branch of the Patapsco River in downtown Baltimore.

Owings Mills is designated as one of the county’s growth areas and much of this portion of the watershed has experienced development particularly along the I-70 and Reisterstown Road corridor. The watershed lies almost entirely within the Urban Rural Demarcation Line and is serviced by water and sewer. The watershed has a population of 356,000 and 74.3 percent of the watershed is classified as urban.

Two major public land holdings are located in the watershed and represent the largest forested segments of the watershed. The Soldiers Delight Natural Environment Area consists of 1,000 acres and is located in Owings Mills. The property protects and preserves unusual serpentine barren habitat with 39 rare and endangered species. In Baltimore City, the 1,200 acre Leakin Park is one of the largest urban wilderness parks on the East Coast and also contains the trail heads for the 154-mile Gwynns Falls Trail. This urban greenway is a walking and biking trail that links with the Inner Harbor promenade and is part of the East Coast Greenway and the Chesapeake Bay Gateways Network. 

Small Watershed Action Plan

A small watershed action plan (SWAP) identifies strategies to bring a small watershed into compliance with water quality criteria. Strategies go beyond traditional government capital projects and include actions in partnership with local watershed associations, citizen awareness campaigns and volunteer activities.

Middle Gwynns Falls

A SWAP has been completed for the Middle Gwynns Falls watershed. This planning area includes communities in Randallstown, Woodlawn and a portion of Pikesville, which drain to the Gwynns Falls main stem, Scotts Level, Powder Mill Run, Dead Run and Maiden Choice Run.

  • SWAP Volume 1 (PDF) outlines the actions identified as part of the strategy.
  • SWAP Volume 2 (PDF) contains the results of the field and geographic information systems data assessments.
  • Addendum A (PDF) provides the Sediment and Bacteria TMDLs Analysis and Actions.

Upper Gwynns Falls

A SWAP has been completed for the Upper Gwynns Falls.

  • SWAP fact sheet (PDF) describes the Upper Gwynns Falls planning area.
  • SWAP Volume 1 (PDF) outlines the actions identified as part of the strategy.
  • SWAP Volume 2 (PDF) contains the results of the field and GIS data assessments.

Watershed Management Plan

The Gwynns Falls Watershed was the first watershed designated in the City and County Watershed Agreement for development of a collaborative watershed management plan (PDF). The watershed management plan identifies three primary joint goals to identify non-point source stormwater pollution, determine methods to reduce non-point source pollution and to provide a planning tool for capital restoration projects.

Baltimore Ecosystem Study

The Gwynns Falls Watershed was selected as an urban study area for the Baltimore Ecosystem Study. Baltimore City is one of two urban locations funded by the National Science Foundation and chosen as part of their Long-Term Ecosystem Research program. The Gwynns Falls Watershed has been the subject of research projects by many of the scientists working on the project.

Volunteer Activities

To participate as a volunteer for the Gwynns Falls watershed, contact Blue Water Baltimore, formerly the Gwynns Falls Watershed Association.

Revised June 28, 2021         


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