Heavy rainfall and too much fertilizer may be causing serious water quality problems for Lake Lanier, according to environmental watchdog group Chattahoochee Riverkeeper.
Over the past two years, chlorophyll levels at five monitoring sites between Buford Dam and Browns Bridge have exceeded state standards, the group said in a news release Tuesday, March 9.
Chlorophyll is the main indicator used to detect algae, which blooms as result of excess nutrients flowing into the lake. Too much algae in the water can “negatively affect water quality, impact taste and smell of drinking water even after treatment, raise the cost of treating water to meet drinking water standards, and cause decreased oxygen levels that fish and other aquatic life need to survive,” Chattahoochee Riverkeeper says.
Much of the pollution is caused by stormwater runoff from fertilizers used on lawns and farms. Other sources include treated sewage discharges, failing septic systems and clogged sewer pipes from improper household disposal of fats, oil and grease, the group says.
“We are working with several local governments, utilities and other stakeholders to address this problem, but individuals who reside in the watershed have a critical role to play as well,“ said Dale Caldwell, the group’s headwaters director. “Cumulative and seemingly small impacts can multiply and lead to a positive impact on this very valuable water source.”
Linda MacGregor, director of the Gainesville Department of Water Resources, said that excess nutrients in the lake, combined with various environmental factors, “can cause taste and odor anomalies in drinking water.
“We monitor these parameters and adjust our drinking water processes to address changes,” she added.
Also, Gainesville has invested in a powdered-activated carbon system at its Riverside Water Treatment Plant to address taste and odor compounds. The city is in the process of adding similar facilities at its Lakeside Water Treatment Plant, MacGregor said.
Otherwise, people can help by limiting the amount of fertilizers they put on their lawns, routinely maintaining their septic systems and not pouring fats, oils and greases down the drain.
Chlorophyll levels are higher than they have been since Chattahoochee Riverkeeper began testing in 2010 and since Georgia Environmental Protection Division began testing in 2000, the group says.
The EPD sets chlorophyll limits at five monitoring locations on the lake.
Lake Lanier contained more algae in 2019 than in the previous 20 years, according to data reported last year by Chattahoochee Riverkeeper.
Data collected by Chattahoochee Riverkeeper is averaged with data collected by the EPD and Gwinnett County’s Department of Water Resources. Between 2000 and 2018, these monitored chlorophyll levels increased at an average of 0.17 micrograms per liter each year. Between 2018 and 2019, however, the increase was about 3.72 micrograms per liter.
Jennifer Flowers, executive director of the Lake Lanier Association, said that last year, her group documented nine cyanobacteria blooms, which can produce potentially harmful blue-green algae.
They weren’t large blooms, but the number of them was “concerning,” she said.
“We don't know what will happen this year as the algae growth is very dependent upon the weather and the runoff that is flushed into the lake.”
The group plans to stay on top of the issue through working with area governments, educating its members and providing a way for people to report issues on its website in a “See Something, Say Something” program rolling out this spring, according to the association’s newsletter released Monday, March 8.
“There are many examples across the nation where nutrient pollution has gone unchecked to the detriment to the community as a whole,” Flowers said. “An ounce of prevention will lead to a pound of cure and in this case, the long-term health of Lake Lanier.”