The 20-year spike in algae levels recently reported on Lake Lanier occurred last summer and was likely weather-related, according to a Georgia Environmental Protection Division official. Measurements of chlorophyll a, the main indicator used to detect algae, rose “off the charts” last summer in reservoirs and streams statewide, said Elizabeth Booth, EPD manager of watershed planning and monitoring.
She theorized the increase was sparked by near record rainfall in 2018 that loaded Georgia waterways with runoff stoked with nutrients, such as those in fertilizers. Nutrients then simmered in spring and summer sunshine and cooked up algae blooms throughout the state. Lanier was not the sole reservoir sporting green. Data collected on all 28 lakes and 11 estuaries monitored by EPD showed elevated chlorophyll a levels, Booth said.
She stressed that the widely reported levels occurred in summer 2019 and that annual test data was compiled early this year. The state agency, along with Chattahoochee Riverkeeper and other entities, sample water April-October. Media outlets pounced on the high chlorophyll a count on Lanier after CRK disseminated an early February press release about last year’s data.
One newspaper erroneously reported a “spike in bacteria,” mistakenly labeling the algae-producing material. Chlorophyll a is a pigment in green plants that absorbs light for photosynthesis to produce food. Nutrients such as nitrogen and phosphorus fuel the process. When nutrient loadings are high, algae can proliferate, thus increasing the amount of measurable chlorophyll a in the water.
Julia Regeski, CRK communications manager, said the press release contained the environmental group’s latest information about chlorophyll a levels. She explained that it takes about a month for independent laboratories to analyze algae data. The one-month turn around after the final test in October postponed actual result posting until November or December. Then, the results got checked for quality assurance and the annual data from each testing station was compared to state standards. “This data is collected over long periods of time and indicate problems that will also require long periods of time to correct,” Regeski said.
Too much algae in the water can negatively affect water quality, impact taste and smell of drinking water and raise the cost of treating to drinking water standards, according to CRK. Booth said that most of the time, water treatment plants can alleviate odor or taste problems before water reaches household faucets. Although excess algae can decrease oxygen needed by fish and aquatic life, anglers might make some big hauls near algae. Booth said fish love to eat it. But she cautioned against swimmers and pets getting into algae-infested water. “Blue-green algae blooms are toxic … it can make people and pets sick.”
Booth believes run-off from non-point sources after heavy rains, not from permitted facilities such as wastewater treatment plants, loaded reservoirs and tributaries with nitrogen and phosphorus in 2018. According to EPD, non-point “sources of nutrients in urban areas include wastes that are attributable to fertilizers, domestic animals, leaks and overflows from sanitary sewer systems, illicit discharges of sanitary waste, leaking septic systems, runoff from improper disposal of waste materials, and leachate from both operational and closed landfills.” In agricultural areas, nutrients may flow in from “animals grazing in pastures, manure application, manure lagoons, and direct access of livestock to streams. Wildlife, especially waterfowl, can also be a significant source of nutrients.”
As the weather warmed in 2019, the nutrient-laden soup grew algae, resulting in last summer’s high chlorophyll a level. Booth expects “very interesting” chlorophyll a testing this summer after another winter of extraordinary rainfall, especially in Lanier’s watershed. Heavy February rain may have “washed everything off,” diluting and transporting nutrients out of the lake or may have washed more nutrients in. If the latter scenario occurred, a warm spell this month or April might percolate some algae blooms, she said.
If folks want visual evidence of chlorophyll a on Lanier, they may see it at Four Mile Creek in Forsyth County when the weather warms, according to Dale Caldwell CRK Headwaters Director. Caldwell and Riverkeeper Jason Ulseth boat a 70-mile route once a month April-October collecting samples at Lanier Bridge, Boling Bridge, Brown’s Bridge and upstream from Flowery Branch and Buford Dam. CRK has monitored Lanier and tributaries since 2010. EPD’s testing started in 2000. Caldwell said CRK and EPD crews sample independently on different days. Gwinnett County also tests water quality. EPD averages the results to get the data.
According to the Feb. CRK press release, between 2000 and 2018, the monitored chlorophyll a levels increased at an average of .17 milligram per liter. Between 2018 and 2019, however, the increase exceeded 20 times the previous average, reaching 3.72 mg/l. Even before the recent data was recorded, EPD’s 2017 evaluation of chlorophyll a in Lake Lanier sounded an alarm in a 90-page document. “It is believed that if nutrient loads are not reduced, the lake will continue to degrade over time. Remedies exist for addressing excess nutrients from both point and nonpoint sources,” it says before outlining plans to reduce total nutrient load.
“The high algae levels that we saw in 2019 indicate that we need to do a better job of controlling the amount of nutrients flowing into the lake,” Caldwell said. He attributed excess nutrients to a “a combination of things,’ from lawn fertilizers, faulty septic tanks, livestock on small farms, and possibly from municipal facilities in Lanier’s headwaters that may lack up-to-date water treatment practices. He also cited heavy rainfall and resultant stormwater runoff as potential factors, but not ones that can excuse landowners and facilities from responsible practices. “I don’t deny (weather) is a factor, but the (increase in chlorophyll a) is not fully driven by rain over the years,” he said. “We strongly advocate for everybody to cough up the money for good practices, good treatments that impact everybody,” Caldwell said.
For instance, he mentioned that homeowners and developments looking to green up their lawns this spring should be mindful of the weather forecast and their own soil composition before applying fertilizer. He recommended landowners get a soil test from their county extension office to determine the type and amount of fertilizer they need rather than spreading bag after bag of popular nutrients they may not need. Additionally, landscapers should take care not to fertilize within two days of predicted rain, after which a deluge might wash nutrients into the watershed.
Caldwell mentioned that press releases are a CRK tactic to motivate people to take action. “We want this in the media. We want people to care,” he said. “We want people to speak up and comment to EPD” about cleaning up the nutrient load on the lake.
The high chlorophyll a level last year highlights the need for the EPD clean-up plan outlined in 2017 and mandated by the federal government to target nutrient reductions in the Lanier watershed, said Ulseth, CRK Riverkeeper.