Indiana Administrative Code (Last Updated: December 20, 2016) |
Title 327. WATER POLLUTION CONTROL DIVISION |
Article 327IAC5. INDUSTRIAL WASTEWATER PRETREATMENT PROGRAMS AND NPDES |
Rule 327IAC5-1.5. Definitions |
Section 327IAC5-1.5-66. "Total maximum daily load" or "TMDL" defined
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"Total maximum daily load" or "TMDL" means the sum of the individual wasteload allocations for point sources and load allocations for nonpoint sources and natural background minus the sum of a specified margin of safety and any capacity reserved for growth. If a receiving water has only one (1) point source discharger, the TMDL is the sum of that point source WLA plus the LAs for any nonpoint sources of pollution and natural background sources, tributaries, or adjacent segments minus the sum of a specified margin of safety and any capacity reserved for growth. TMDLs can be expressed in terms of either mass per time, toxicity, or other appropriate measure. If best management practices (BMPs) or other nonpoint source pollution controls make more stringent load allocations practicable, then wasteload allocations may be made less stringent. Thus, the TMDL process provides for nonpoint source control tradeoffs. A TMDL sets and allocates the maximum amount of a pollutant that may be introduced into a waterbody and still assure attainment and maintenance of water quality standards. (Water Pollution Control Division; 327 IAC 5-1.5-66; filed Jan 14, 1997, 12:00 p.m.: 20 IR 1420; readopted filed Jan 10, 2001, 3:23 p.m.: 24 IR 1518; readopted filed Nov 21, 2007, 1:16 p.m.: 20071219-IR-327070553BFA; readopted filed Jul 29, 2013, 9:21 a.m.: 20130828-IR-327130176BFA)