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Patapsco Non-Tidal Watershed

Patapsco Non-Tidal Watershed

Watershed Description

The Patapsco Non‐Tidal watershed is situated in the northwestern portion of the County. The watershed shares political boundaries with Howard County along Deep Run and Baltimore County along the mainstem of the Patapsco River. The most downstream extent of the watershed bounds Baltimore City in the most northern extent of the County. It includes the communities of Brooklyn Park, Pumphrey, North Linthicum, Linthicum Heights, Linthicum Hills, Kignston Heights, Hanover, Harmans, Severn Hills, Sandal Wood and Stoney Run.

The Patapsco Non‐Tidal watershed is approximately 15,281 acres in area. The watershed includes several named streams including Stoney Run, Piney Run, Deep Run, Holly Creek, and the mainstem of the Patapsco River.  These named streams are distributed among 12 sub-watersheds ranging in size from 431 to 2,646 acres. The Patapsco Non‐Tidal Watershed contains approximately 96 total miles of streams. 

Land use throughout the watershed varies. Woods occupy a majority of the watershed, representing approximately 37% of the total area. Collectively, residential land cover categories constitute almost 25% of the watershed. Open space represents the next largest portion of the watershed and occupies over 11% of the total area. Industrial, transportation, commercial, and airport land covers all individually occupy 4% ‐ 10% while water, open and forested wetlands, utilities, row crops, residential woods, pastures/hay, and undesignated covers are all individually less than 0.5%. Impervious surfaces represented by roads, building footprints, parking lots and other hard surfaces cover approximately 28% (~4,352 acres) of the Patapsco Non-Tidal watershed.

The Patapsco Non‐Tidal watershed has been developed over the course of several centuries.  The earliest documented development occurred in the late 1700’s and has continued to increase, exponentially so, through the present.   Development peaked between 1980 and 1999 before stormwater management regulations for water quality were put in place in 1999. However, a significant amount of development has continued to occur even after water quality regulations were developed. The majority of the development in the last decade has occurred along the Baltimore‐Washington Parkway. 

The Patapsco NonTidal watershed contains portions of several major transportation corridors including Interstate 695, Interstate 195, MD Route 100 and the Baltimore Washington Parkway. In addition, a majority of the Baltimore Washington Thurgood Marshall International Airport is located within the boundaries of the watershed. Other major landmarks include Patapsco Valley State Park which borders Baltimore County in the north, Arundel Mills Mall, and several County Parks including Pumphrey Park, Overlook Park, Jessup/Dorsey Park and Joe Cannon Stadium.

Watershed Assessment

The Watershed Protection and Restoration Program utilizes a watershed based approach to restoring and protecting our waterways. Assessments are conducted on each of the 12 primary watersheds to evaluate water conditions, establish priorities and goals for improvement, and take actions designed to restore or protect water quality.

A comprehensive watershed assessment for the Patapsco Non-Tidal watershed has been completed. The reports include a discussion of the water quality problems and sources of pollution and strategies for improving the water quality in the watershed. Click here to read more.

Local Watershed Organizations

Successful conservation and preservation of Anne Arundel County's watersheds takes teamwork. Here is a list of organizations that work to protect the Patapsco Non-Tidal watershed:

Anne Arundel Patapsco River Alliance
Anne Arundel County Watershed Stewards Academy


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