Total Maximum Daily Load (TMDL)
DEQ manages the Total Maximum Daily Load (TMDL) 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.
Southeast Oklahoma Draft Bacteria and Turbidity TMDL Report and Public Notice
Please submit comments in writing to: Soojung Lim, Water Quality Division, Oklahoma Department of Environmental Quality, PO Box 1677, Oklahoma City, OK 73101-1677
or by email at Water.Comments@deq.ok.gov
Public Notice for the Southeast Oklahoma Bacteria and Turbidity TMDL – Comment period closes June 27, 2025
Southeast Oklahoma Bacteria and Turbidity Draft TMDL Report
Southeast Oklahoma Bacteria and Turbidity Draft TMDL 208 Fact Sheet
Arkansas – Keystone Basin Study Area Draft Bacterial TMDL Report and Public Notice
Please submit comments in writing to: Soojung Lim, Water Quality Division, Oklahoma Department of Environmental Quality, PO Box 1677, Oklahoma City, OK 73101-1677
or by email at Water.Comments@deq.ok.gov
Public Notice for the Arkansas – Keystone Basin Bacterial TMDL – Comment period closes June 20, 2025
Arkansas – Keystone Basin Draft TMDL Report
Arkansas – Keystone Basin Draft TMDL 208 Fact Sheet
Neosho and Verdigris Basins Bacterial and Turbidity Draft TMDL Report and Public Notice
Please submit comments in writing to: Tamara Scott, Water Quality Division, Oklahoma Department of Environmental Quality, PO Box 1677, Oklahoma City, OK 73101-1677
or by email at Water.Comments@deq.ok.gov
Public Notice for the Neosho and Verdigris Basins TMDL – Comment period closes May 9th, 2025
Neosho and Verdigris Basins Draft TMDL Report
Neosho and Verdigris Basins Draft TMDL 208 Fact Sheet
Lake Oologah TMDL Report
Public Notice for the Lake Oologah Draft TMDL
Lake Oologah Draft TMDL Report
Appendix A – Data Acquisition and Assessment
Appendix B – Watershed Model Calibration and Validation Report
Appendix C – EFDC Hydrodynamic and Water Quality Model
Appendix D – Oklahoma Antidegradation Policy
Appendix E – Water Withdrawals in Verdigris River Basin
Appendix F – Sanitary Sewer Overflow Bypass Events
Appendix I – Ambient Monitoring Data at Watershed and Lake Stations
Appendix J – Stormwater Permitting and BMPs
Fort Gibson Lake TMDL Report
Public Notice for the Fort Gibson Lake Draft TMDL
Fort Gibson Lake TMDL – EPA Approval Letter
Fort Gibson Lake Draft TMDL Report
Appendix A – HSPF Watershed Model
Appendix C – Antidegradation Policy
Appendix D – Ambient Monitoring Data
Appendix E – Stormwater Permitting and BMPs
Appendix F – SSO Bypass Events
Appendix I – Distributions for Maximum Daily Loads
Fort Gibson Lake 208 Factsheet
Contact Watershed Planning
An interactive map of Oklahoma’s waterbodies is available at http://gis.deq.ok.gov/maps/.