Lake Thunderbird TMDL Project

Lake Thunderbird is located east of Norman, Oklahoma, with a drainage area covering large parts of the Cities of Norman, Oklahoma City, and Moore. The lake serves as a drinking water source for the cities of Norman, Midwest City, and Del City. It was designated as a Sensitive Water Supply (SWS) lake by the State of Oklahoma in 2002. It is also a major recreation destination providing boating, fishing and other water related opportunities.

Lake Thunderbird is listed as not supporting the beneficial uses of public and private water supply and warm water aquatic community. The causes of the impairments are low dissolved oxygen (DO), high Chlorophyll-a, and high turbidity. As there are no wastewater discharges in the lake watershed, nutrient and sediment loadings from MS4 stormwater flows and nonpoint sources during runoff events through tributary streams are the major sources of the impairments. Internal processes in the lake also contribute pollutant loadings.

The federal Clean Water Act and related regulations require total maximum daily loads (TMDLs) be developed for impaired waterbodies on a state’s 303(d) list. TMDLs provide goals and guidelines to improve the water quality in these waterbodies. TMDLs for nutrients, turbidity, and dissolved oxygen were completed by DEQ and received EPA approval on November 13, 2013. The TMDLs specify the pollutant load reduction from MS4 permittes and non-point sources for the lake to achieve water quality standards.

The EPA approved TMDL report and associated project documents are available in the following menu.

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