Serving Barnwell County and it's neighbors since 1852
In Barnwell County, Lake Edgar Brown is a beloved attraction that brings visitors from surrounding counties, and contains teeming populations of largemouth bass, turtles, alligators, catfish and bluegill.
Yet, the lake is also known for its ecological issues, namely overgrowths in harmful algal blooms (HABs), with community conversations reemerging in July after locals reported dead fish washing up on the lake’s shores. Concurrently, local public officials and the South Carolina Department of Natural Resources (DNR) have begun efforts to clean up the lake's waters and turn it into a tourism destination.
Fertilizer runoff and excessive heat are the common explanation for HABs, which sicken freshwater ecosystems and have adverse health effects on humans. As greenhouse gasses from burning fossil fuels continue raising the temperature of Earth’s lakes and oceans, HABs are becoming more likely, particularly in freshwater, according to Climate Central, a science non-profit.
But documents from the South Carolina Department of Environmental Control (DHEC) and the Environmental Protection Agency (EPA) reviewed by The People-Sentinel provide a larger picture; Lake Brown’s pollution dates back decades, with the lake’s ecosystem having been unstable since its inception.
A polluted history
Lake Brown was first created in the early 1960s by damming Turkey Creek, which flows through the City of Barnwell from the outskirts of Elko before joining up with the Salkehatchie River south of town.
In 1968, Turkey Creek was diverted around the lake. Since then, the only source of water to the lake has been rainwater and runoff, and the lake has no tributaries, according to a report by DHEC’s Bureau of Water.
The original intention was to build a fishing lake for the community. But in order to build an ecosystem that would support a large population of fish, the city first needed to fill the lake with algae, a foundation of a freshwater ecosystem’s food chain. So, the 96-acre lake was fertilized with 3,858 pounds of phosphorus (a nutrient that encourages plant growth) every year between 1968 and 1977, according to the Bureau of Water report. All told, 38,581 pounds of phosphorus were dumped into the lake.
At a certain point, a pipe was built underneath the land barrier that separates Turkey Creek and Lake Brown to keep fresh water flowing into the lake. But over time, mud and debris closed the pipe, according to Barnwell County Council chairman Jerry Creech.
The phosphorus overperformed. DHEC scientists reported that the lake’s ecosystem was quickly transformed as HABs of polycystic aeruginosa — a pathogen with a wide variety of adverse health effects ranging from infection and burns to respiratory issues — filled the lake's waters. Harmful algal blooms were not just occurring during the typical summer months but also during winter, DHEC reported.
As algal blooms exploded, the lake’s pH levels rose above the state’s water quality standard; during photosynthesis, algae release hydroxide as a byproduct. With no freshwater tributary to flush out the excess phosphorus, the dammed up lake’s ecological issues persisted throughout the 1980s and 1990s.
Oxygen levels in the lake also fell. In 1988, DHEC sent the United States Congress a Clean Water Act water quality assessment that ranked Lake Brown as the third highest minor lake in South Carolina by eutrophication. In other words, the lake was the third highest in the state for its excess amounts of nutrients that encourage the growth of aquatic plant life like algae at a cost to oxygen levels and animal life.
“[In] a well-balanced ecosystem, every single component occupies its own niche, including the predator-prey relationship and other forms of competition,” said Meiyin Wu, an aquatic ecologist at Montclair State University. “Sometimes, a certain change would tip the balance in one way. In this case, when you have an overgrowth of, that causes the components that keep them in check to become less dominant.”
Between 1986 and 1995, 99 percent of test samples from Lake Brown exceeded EPA phosphorus recommendations: “The lake no longer possesses a balanced indigenous aquatic community,” the DHEC document states.
In 2000, the lake was among a DHEC list of bodies of water in South Carolina that were “violating aquatic life standards,” which was sent to the EPA. The Bureau of Water report recommended reconnecting Turkey Creek as a tributary to Lake Brown to decrease phosphorus loads in the lake.
“As long as the flushing rate exceeds … growth rates, recurring algal blooms will not be a problem,” the Bureau of Water report stated. “A 77 percent reduction in phosphorus loading will be necessary to meet water quality standards during the critical period.”
But Turkey Creek also struggles with high levels of per- and polyfluoroalkyl substances (PFAs), a group of toxic chemical compounds often called “forever chemicals” that never break down and are associated with adverse health effects on both humans and animals. DHEC tests from April 2023 found PFAs levels in Turkey Creek at 746 parts per trillion, over 186 times the EPA’s limit of four parts per trillion.
Lake Brown has also been tested for PFAs, which can accumulate in the flesh of fish. Industrial PFAs pollution in the local watershed has been previously reported by The People-Sentinel.
Modern problems
Both toxic and nontoxic algae blooms have persisted at Lake Brown in recent years, most notably in 2020, when DHEC issued a recreational water advisory following the discovery of HABs in the lake's waters.
At the time, DHEC’s manager of aquatic science programs, Bryan Rabon, said: “Until further notice, no one should swim, wade or come into contact with the water or scum, foam or algae at Lake Edgar Brown.”
The extent to which the phosphorus dumping of the 1960s and 1970s are still affecting the lake’s algae blooms are “inconclusive,” according to Ross Self, Chief of Freshwater Fisheries at DNR. Self believes that fertilizer runoff from other sources, such as local agriculture and roads may also be contributing to the problem.
Self noted that higher levels of fertilization can be helpful for the purposes of cultivating a fishing lake.
“An unfertilized lake in the south is probably capable of supporting 150 or 200 pounds of fish per acre,” Self said. “When you start fertilizing you can bump that up to 400 or 500 pounds per acre. When you’re managing fish for recreational fishing for the public, you want a robust enough fish population.”
The fish kill that occurred in Lake Brown was likely not a result of HABs, Self said. The fish that died were mostly threadfin shad, a small freshwater fish species whose populations are cultivated in fishing lakes to feed larger fish like bass, and are more vulnerable than other fish species to high temperatures.
“SCDNR biologists believe high water temperatures were the likely cause,” said Greg Lucas, DNR’s public information officer. “The biologists investigating the kill observed that dead fish appeared to be older, post-spawn individuals, and that mortality coincided with a period of extreme heat.”
This summer, as Barnwell, Allendale and the broader southeast ricocheted between triple-digit heat waves, The People-Sentinel reported that human-caused climate change was making those heat waves more likely, and in one case four times more likely. In addition to increasing atmospheric temperatures, climate change is raising water temperatures, which increases the intensity and frequency of HABs.
“Climate change has a couple different ways it affects harmful algal blooms,” Wu said. “We have elevated temperatures and are able to grow faster at hotter temperatures. During drought conditions, water levels are lower and that increases nutrient concentration. We have intensifying storms in North America, which increase runoff and erosion of nutrients.”
Ongoing development and solutions
This summer's fish kill and the resurfacing of Lake Brown’s ecological turmoil has occurred concurrently with local efforts to transform the lake into a tourist attraction.
The areas surrounding the lake are currently undergoing development. On August 13, the Barnwell County Council approved the third reading of an ordinance to purchase 15 acres surrounding Lake Brown for the construction of an amphitheater, pursuant to a capital project sales tax funding approval.
DNR is also seeking bids to repave the parking lots and boat ramps near the lake, and the city and county are partnering to bring kayaks to the lake. The South Carolina Heritage Trust Program is another group involved in recent efforts to revitalize the lake.
On August 15, biologists from DNR, which manages Lake Brown, met with the Barnwell County Council. DNR has installed what Lucas describes as an “ultrasonic algae remediation device” on the lake.
“Blue-green algae cells contain gas vesicles, which are small, air-filled compartments that allow them to float, “ Lucas said. “The new remediation device emits sound waves at a specific frequency that causes the walls of these compartments to burst–much like an opera singer shattering a wine glass. The blue-green algae then sinks to the bottom of the lake and dies, leaving fish and beneficial aquatic plants unharmed.”
The device, powered by solar panels, currently floats on the south side of the lake. But the lake remains disconnected from the less stagnant waters of Turkey Creek, which is DNR’s next project for the lake.
“In our state budget request, we’re requesting funds to install water exchange structures [in Lake Brown],” Self said. “It’s a little more complicated than putting a pipe through the dike. We need to be able to control the amount of water going in and coming out.”
Self said hydrologists and engineers will have to get involved in constructing a water exchange structure that acts as a long-term solution.
Until then, it may be a while before Lake Brown’s ecosystem finds harmony.
Elijah de Castro is a Report for America corps member who writes about rural communities like Allendale and Barnwell counties for The People-Sentinel. Your donation to match our RFA grant helps keep Elijah writing stories like this one; please consider making a tax-deductible gift of any amount today.
