Question

Describe TMDL in detail?

Answer 1

TMDL stands for "Total Maximum Daily Load". A TMDL is a calculation of the maximum amount of a pollutant that a waterbody can accept and still meet the state's Water Quality Standards for public health and healthy ecosystems. The federal Clean Water Act requires all states to identify water bodies that do not meet state standards and develop TMDLs for them.

TMDL = ΣWLA + ΣLA + ΣMOS

ΣWLA = Waste Load Allocations

It is Point source (i.e. end of pipe discharge).

ΣLA = Load Allocations

It is Non-point sources (i.e. precipitation runoff) and Non-regulated.

ΣMOS =  Margin of safety

It Considers natural background.

Who is responsible for developing a TMDL?

As a general matter, states are responsible for developing TMDLs and submitting them to EPA for approval. Even if third parties assist in the development of the TMDL or its supporting analysis, such TMDLs must still be submitted to EPA by the states.