Baltimore Harbor Watershed, Baltimore City, Baltimore County and Anne Arundel County, MD

Notice of Intent to Establish a TMDL for Sediments

Section 303(d) of the federal Clean Water Act (CWA) directs States to identify and list waters, known as water quality limited segments (WQLSs), in which current required controls of a specified substance are inadequate to achieve water quality standards.  For each WQLS, the State is required to establish a Total Maximum Daily Load (TMDL) of the specified substance(s) that the waterbody can receive without violating water quality standards, demonstrate that another program or action will achieve water quality standards, or demonstrate via the development of a Water Quality Analysis (WQA) that water quality standards for the specified substance(s) are currently being achieved.  The Maryland Department of the Environment (MDE) hereby gives notice of the public availability of a draft TMDL document for Sediment for the Baltimore Harbor Watershed (basin code 02130903).

The Maryland Department of the Environment (MDE) identified the waters of the Baltimore Harbor watershed and associated assessment units on the State’s 2018 Integrated Report as impaired by multiple pollutants including sediment or total suspended sediment (TSS). The Baltimore Harbor watershed is associated with three assessment units in Maryland’s Integrated Report: a non-tidal 8-digit watershed (02130903) and two estuary portions [Chesapeake Bay Segments Upper Chesapeake Bay Mesohaline (CB3MH) and Patapsco River Mesohaline (PATMH)]. For more details about these listings, please see the TMDL report being made available for public comment. A data solicitation for TSS/sediment was conducted by MDE in November 2018, and all readily available data has been considered.

The TMDL sets the maximum load limit for the impairing substance.  The TMDL also reflects load allocations to point sources, nonpoint sources and a margin of safety that accounts for uncertainty in the procedures used to estimate the TMDL.  Once established by the State, the TMDL will be subject to approval by the U.S. EPA.  The approved TMDL will support measures needed to attain water quality standards in the Baltimore Harbor Watershed.


A 30-day public comment period for the draft document will take place from August 24, 2020 to September 22, 2020.  The draft document is available on the Internet at web site under Drafts for Public Comment or by contacting Ms. Melissa Chatham by email at, or by telephone at 443-908-0338 (outside the Baltimore area, dial 1-800-633-6101 x3937).  Anyone  wishing to review the draft documents and supporting information or needing technical information may contact Ms. Chatham during normal business hours.

Written comments concerning the draft document may be submitted to the Department on or before September 22, 2020 and should be sent to Ms. Chatham at the above address or emailed to  All comments received during the comment period will be considered and the draft document may be revised accordingly prior to its submittal to EPA for approval.

Draft Total Maximum Daily Load of Sediment
in the Non-Tidal Baltimore Harbor Watershed, Baltimore City, Baltimore County and Anne Arundel County, MD

Fact Sheet Baltimore_Harbor_TSS_TMDL_fact_sheet.pdf (314KB)
Main Report Baltimore_Harbor_Sed_TMDL_PN.pdf (2478KB)
Point Source Technical Memorandum Baltimore_Harbor_Sed_TMDL_PS_TechMemo.pdf (198KB)
Nonpoint Source Technical Memorandum Baltimore_Harbor_Sed_TMDL_NPS_TechMemo.pdf (161KB)

Additional Supporting Information

Biological Stressor Identification Baltimore Harbor Watershed Report (700KB)

Biological Stressor Identification Methodology (459KB)

Nontidal Sediment TMDL Methodology Report (361KB)

Addendum to the Nontidal Sediment TMDL Methodology Report (23KB)