The Official Website of the Massachusetts Bays Program


What are TMDLs?

A total maximum daily load (TMDL) is the greatest amount of a pollutant that a waterbody can accept and still meet water quality standards for protecting public health and maintaining the designated beneficial uses of those waters for drinking, swimming, recreation, and fishing. A TMDL is essentially a clean-up plan required through the Federal Clean Water Act and is implemented by specifying how much of that pollutant can come from point, nonpoint, and natural sources. States are required to identify and list waterbodies that are threatened or not meeting water quality standards despite controls on point source discharges. This list, referred to as the "Massachusetts Integrated List of Waters," is updated every two years by the Massachusetts Department of Environmental Protection (DEP).

DEP has developed a TMDL Strategy that prioritizes all listed waterbodies, establishes TMDLs for degraded waters, and plans for implementation of best management practices (BMPs) to clean up polluted waterbodies.

Click on any of the communities in the map below to view maps of waterbodies within the Massachusetts Bays region that are included in the 2002 Integrated list of waters (a chart below the map explains how the waterbodies are categorized). Please note that the 2002 data is the most recent GIS data available, however a final 2004 Integrated List of Waters and proposed 2006 list are now available and do include some changes since 2002. Visit the DEP TMDL website to download the most recent reports.

303d map TMDL map for Rowley, Ipswich, and Essex TMDL map for Amesbury, Salisbury, Newburyport, Newbury, and Rowley TMDL map for Essex, Gloucester, Rockport, and Manchester TMDL map for Manchester, Beverly, Danvers, Peabody, Salem, Marblehead, Swampscott, Lynn, and Nahant TMDL map for Danvers, Peabody, Salem, Nahant, Lynn, Saugus, Revere, Chelsea, and Everett TMDL map for Chelsea, Everett, Winthrop, Boston, Quincy, Braintree, and Weymouth TMDL map for Weymouth, Hingham, Hull, Cohasset, Scituate, Norwell, Marshfield, Hanover, Pembroke, and Duxbury TMDL map for Hanover, Norwell, Marshfield, Pembroke, Duxbury, Kingston, and Plymouth TMDL map for Kingston, Plymouth, and Bourne TMDL map for Sandwich and Barnstable TMDL map for Barnstable, Dennis, Yarmouth, and Brewster TMDL map for Wellfleet, Orleans, Eastham, and Brewster TMDL map for Provincetown, Truro, and Wellfleet

The mapped waterbodies are categorized as follows:
Category Description
Category 1 Attaining all designated uses.
Category 2 Attaining some of the designated uses and insufficient or no data and information is available to determine if the remaining uses are attained.
Category 3 Insufficient or no data and information to determine if any designated uses are attained.
Category 4a Impaired for one or more designated uses but does not require the development of a TMDL: TMDL has been completed.
Category 4b Impaired for one or more designated uses but does not require the development of a TMDL: Other pollution control requirements are reasonably expected to result in the attainment of designated uses.
Category 4c Impaired for one or more designated uses but does not require the development of a TMDL: Impairment is not caused by a pollutant.
Category 5 Impaired for one or more designated uses, requires the development of a TMDL: Impairment is caused by a pollutant.

Data on all maps courtesy of the Office of Geographic and Environmental Information (MassGIS), Commonwealth of Massachusetts Executive Office of Energy and Environmental Affairs.

URL: www.mass.gov/envir/massbays/tmdl.htm
Updated 04/27/09

learn more
For more Massachusetts GIS data visit MassGIS.

For more on TMDLs in Massachusetts, see the Mass DEP TMDL page.