Total Maximum Daily Load (TMDL)
DEQ manages the Total Maximum Daily Load program for the State of Oklahoma. A TMDL is the process of establishing the sources of impairment in a given waterbody, whether from point sources (discharges) or non-point sources (runoff), determining the amount of reduction necessary to meet water quality standards in that waterbody, and allocating the loads to the various contributors of pollution. A margin of safety is also included in the TMDL calculation process.
Water quality modeling is the linkage between the sources of pollution and the instream water quality of a given waterbody. A model is a representation of the water-quality processes that occur in a given waterbody. Water quality modeling can be resource-intensive. Different levels of complexity may be used depending on the level of confidence required in a given situation.
An interactive map of Oklahoma’s waterbodies is available at http://gis.deq.ok.gov/maps/.