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Total Maximum Daily Load

Total Maximum Daily Load

What is a TMDL?
Simply stated, Total Maximum Daily Load (TMDL) is the amount of a particular pollutant that a particular stream, lake, estuary or other water body can 'handle' without violating state water quality standards. Once a TMDL is established, responsibility for reducing pollution among both point sources (discharge pipes) and non point sources is assigned. Non point sources include, but are not limited to, run-off from urban, residential, agricultural, and construction areas, stream channel alteration, and damage to riparian areas. Clean up is ultimately the responsibility of everyone who lives, works or plays in a watershed that drains into an impaired water body. However, according the Clean Water Act, EPA is responsible ... if the states forgo their responsibility. Perry County currently has 8 impaired streams however the County has no streams with TMDL status. To view streams with a TMDL in Pennsylvania click on the following link to go to the DEP Emap webpage
 
Establishing a TMDL

  • Identify waters that do not meet water quality standards. In this process, the state identifies the particular pollutant(s) causing the water not to meet standards.
  • Prioritize waters that do not meet standards for TMDL development (for example, waters with high naturally occurring "pollution" will fall to the bottom of the list).
  • Establish TMDLs (set the amount of pollutant that needs to be reduced and assign responsibilities) for priority waters to meet state water quality standards. A separate TMDL is set to address each pollutant with concentrations over the standards.
  • Strategy to reduce pollution and assess progress made during implementation of the strategy. This is when a watershed partnership most likely will want to get involved. If the partnership has already developed a plan of action, it should be shared with the state. In fact, several states have incorporated watershed partnership plans in the state's strategy for specific TMDLs.