NORMAN — The state Environmental Quality Department will hold an informational meeting Thursday on water quality issues affecting Lake Thunderbird.
The meeting will be from 6:30 to 8:30 p.m. in the Lowry Room at the Norman Public Library, 225 N Webster Ave.
State officials will discuss work toward establishing “total maximum daily loads” for the lake. Total maximum daily loads is a regulatory term in the U.S. Clean Water Act, which is a calculation of the maximum amount of a pollutant that a water body can receive and still meet water quality standards.
Water quality models are used to determine the magnitude of pollutants in the lake and estimate the reduction needed to achieve water quality goals.
Officials will discuss preliminary results of a study using water quality models to determine water quality standards for the lake and provide an update on efforts to establish total maximum daily load amounts.
Lake Thunderbird is a drinking supply for Norman, Midwest City and Del City.
Problems associated with Lake Thunderbird are high chlorophyll-A levels, which come from excessive growth of algae, and high turbidity.
Chlorophyll-A levels in lake water should be no higher than 10 micrograms per liter, according to water quality experts. Lake Thunderbird tests at 60 to 70 micrograms per liter.
The lake also suffers from excessive sedimentation, caused by erosion along streams that feed into it. Sedimentation can introduce toxins into the lake water, which can be difficult to filter out.
Excessive algae growth and sedimentation problems can pose health risks.
In 2002, the state designated Thunderbird as a Sensitive Water Supply lake. The Clean Water Act requires total maximum daily load amounts be established for impaired water bodies on the state list.
The Central Oklahoma Master Conservancy District, Lake Thunderbird's governing body, filed a lawsuit in April against the state Department of Environmental Quality, contending the department has not completed work in a timely manner on establishing total maximum daily load amounts for the lake.
The conservancy district wants a court order that the total maximum daily load project be completed by November.