Patapsco River Lower North Branch
Watershed Characterization

The Patapsco River Basin is entirely in the State of Maryland. The River drains to the Baltimore Harbor area, then to the Chesapeake Bay and eventually to the Atlantic Ocean. One subwatershed within the Patapsco River Basin is known as the Lower North Branch (LNB). It encompasses 118 square miles in Baltimore City and four Counties: Anne Arundel, Baltimore, Carroll and Howard. About 38 square miles of the Patapsco LNB watershed is in Howard County. Howard County is receiving Federal grant funding to prepare a Watershed Restoration Action Strategy (WRAS) for their portion of the Patapsco LNB Watershed.

As part of the WRAS project, the Maryland Department of Natural Resources (DNR) is providing technical assistance, including preparation of a watershed characterization (compilation of available water quality and natural resources information and identification of issues), a stream corridor assessment (uses field data to catalog issues and rate severity) and a synoptic survey (analyzes benthic macroinvertebrates, fish and water samples with focus on nutrients). The County will consider the information generated in these efforts as it drafts the County Watershed Restoration Action Strategy.

Note: (Documents are in PDF format and require Adobe Acrobat Reader which can be downloaded free from