In the Tulsa area, as elsewhere in Oklahoma, there are many streams and lakes that have been designated as impaired. The designation is done according to a specific type of study using data of high quality. The studies are mostly done by the Oklahoma Water Resources Board (OWRB) through their Beneficial Use Monitoring Program (BUMP), and the Oklahoma Conservation Commission (OCC) Water Quality Division. INCOG has contributed to this effort as well as other State and Federal agencies.
The Oklahoma Department of Environmental Quality (ODEQ) must report updates of the impairment list biannually to EPA. In the past this was known as the 303(d) List of impaired waterbodies, but recently ODEQ consolidated the 303(d) Report with the 305(b) report into the “Oklahoma Integrated Water Quality Assessment Report”. Impaired waterbodies in the integrated report are known as Category 5. The latest EPA approved list is dated 2004.
Any waterbody remaining on the Category 5 list will eventually have a special type of pollutant load study called a Total Maximum Daily Load (TMDL). The TMDL characterizes all point source loads (such as wastewater treatment plants) and all non-point source loads (such as agricultural activities) to determine the maximum amount of pollutant loads that can be added from all sources and still maintain water quality. A map of the current 303(d) impaired streams in the INCOG area can be found on the Green Country Stormwater Alliance website.
|In years past, most load studies focused on point sources, and most of these dealt with oxygen-demanding substances. However, within the past few years the emphasis has expanded to include pollutants associated with non-point sources, such as turbidity, pesticides, nutrients and bacteria. The ODEQ website provides a great deal of information about the state’s water quality and regulatory programs to assess and improve our natural resources.
The ODEQ’s Integrated Report states that the greatest causes of waterbody impairment in Oklahoma are pathogens (that is, bacteria) and turbidity. Phosphorus, low dissolved oxygen and dissolved solids comprise a second important group of impairment causes. The toxics (e.g., heavy metals and organic compounds) are also important, but do not constitute the main impairment causes. Most impairment causes have a significant nonpoint source component. Nonpoint sources are much more difficult to characterize (that is, identify and quantify) as well as not being easily controlled through regulatory programs.