Georgia EPD - Lake Lanier Chlorophyll a TMDL Study
The Environmental Protection Division (EPD) recently initiated a major two-year study, including one year of intensive data gathering and one year of advanced water quality modeling, to develop the Chlorophyll a Total Maximum Daily Load (TMDL) for Lake Lanier, and to lay the foundation for future regulatory decisions to be made concerning the Lake Lanier watershed.
Stakeholder involvement will be an important part of this process. We therefore intend for this web page to serve as a bulletin board for all those interested in periodic updates on the project. Accordingly, the contents should grow as the project evolves starting with initial field study plans and progressing to include field data and other activities being performed. Your suggestions about its content will be appreciated. The paragraphs below provide more specific background on this effort.
The Georgia Environmental Protection Division (GAEPD) proposed water quality standards for Lake Lanier in 1999. The Board of Natural Resources adopted water quality standards for Lake Lanier and its major tributaries in 2000. Lake wide standards for pH, total nitrogen, phosphorus, fecal coliform bacteria, dissolved oxygen and temperature were established. Site- specific growing season average chlorophyll a standards (May-October) were set as follows:
Location |
Chlorophyll a |
At Lanier Bridge (State Road 53) on the Chattahoochee River |
10 mg/L |
At Bolling Bridge (State Road 53) on the Chestatee River |
10 mg/L |
At Browns Bridge Road (State Road 369) |
5 mg/L |
Upstream from Flowery Branch Confluence |
5 mg/L |
Upstream from the Buford Dam Forebay |
5 mg/L |
In addition, standards for annual total phosphorus loading were also established for major tributaries to the lake as shown below.
Location |
Annual Phosphorus Load |
Chattahoochee River at Belton Bridge |
178,000 lbs/year |
Chestatee River at Georgia Highway 400 |
118,000 lbs/year |
Flat Creek at McEver Road |
14,400 lbs/year |
In 2006, the Georgia Environmental Protection Division (GAEPD) listed three segments of Lake Lanier on the State’s 303(d) list for not meeting the chlorophyll a water quality standard. These included Lanier Bridge, Browns Bridge, and Flowery Branch. As a result of the listing, the GAEPD will prepare a TMDL for Lake Lanier. The TMDL will be developed using water quality models of the watershed and lake.
The specific purpose of the Lake Lanier Chlorophyll a Study is to evaluate the effects of nutrient loads on lake chlorophyll a concentrations. During 2007, data will be collected to calibrate and validate the watershed and lake water quality models. The modeling will be performed in 2008 and in 2009 the TMDL for Lake Lanier will be prepared by the GAEPD. The field study plan is composed of six coordinated modules. Follow the links below for an overview of the work planned for 2007, followed by specific details on each individual module.
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