A TMDL is a technical analysis that:

determines the maximum loading of the pollutant
of concern a water body can receive and still both
attain and maintain its water quality standards;

and

allocates this allowable loading to pollutant sources
in the watershed. Upon approval by the Commission,
this technical analysis must be submitted to EPA for
review and approval.

TMDL stands for Total Maximum Daily Loads. These projects
evaluate stream and lake segments, ultimately determining the
amount of pollutant which can be contributed by both point and
non-point sources.

For more TMDL information read the Clean Water for Texas document produced by the TCEQ.

Lake O' the Pines TMDL

More Info On TMDL