Approved or Established TMDL Review

A Total Maximum Daily Load (TMDL) is a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards. Industrial activities can generate a number of pollutants in stormwater that can lead to violations of water quality standards, and construction activities typically generate sediment, which can affect related parameters such as turbidity and total suspended solids. Other pollutants may also be of concern, depending on local conditions.

If a TMDL has been established for the waterbody where your site or facility will discharge, and the TMDL (or the state/territory authority) indicates that it applies to construction, industrial, or stormwater discharges, then you must develop a SWPPP that is consistent with the requirements of that TMDL.

• Check the table below to determine the instructions for your state or territory.
• If TMDLs have been established in your state or territory, in most cases you will need to contact your state or territory authority to determine if there are specific TMDL requirements that you must comply with.
• If there are requirements for construction or industrial activities or stormwater discharges, you must incorporate these requirements into your SWPPP and implement necessary steps to meet the TMDL.

Construction activities must comply with all requirements of the CGP, so please review the complete TMDL provisions of the Construction General Permit (PDF) (59 pp, 1.96MB) . Industrial facilities must comply with all requirements in the MSGP-2000, including the provision that all discharges be consistent with established or EPA-approved TMDLs (see section 1.2.3.8.2 in the MSGP-2000 (PDF) (19 pp, 196K)).

There may be additional TMDL-related requirements for your specific state. Certain policies on TMDLs may change. For the most current information, please check this web site or with the TMDL authority each time you plan a construction project.

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Last updated on April 25, 2008 3:39 PM
URL:http://cfpub.epa.gov/npdes/stormwater/tmdl.cfm