Lagoon in mid-2000s aided by natural phenomena
STORY
For more than 10 years prior to 2011, conditions in the Indian River Lagoon improved steadily and dramatically with water clarity increasing and seagrass, the lush green foundation of the lagoon’s ecology, spreading into areas where it had not grown since before the Second World War.
“The water was like what you see in the Keys,” says St. Johns River Water Management District scientist Joel Steward, recalling the glory days in the mid-2000s. “It was better than anyone had ever seen. We were ecstatic.”
Now, ironically, it turns out most of the efforts of agency and elected government officials – who were quick to take credit for the aquatic renaissance – had little to do with the restoration, which was actually caused in large part by a series of natural phenomena, including a prolonged drought and two hurricanes.
Steward, who revealed the disconcerting news about the limited relevance of human efforts in estuary restoration in his keynote address at the Harbor Branch Oceanographic Institute lagoon symposium last month, says the improvements lulled some government officials and entities into an ill-founded complacency.
“A lot of people thought the improvements were the result of actions taken in the watershed. People in positions of authority from the state to the county and other local entities thought, ‘We are doing our job. Everything is going well!’
“The sense of urgency about reducing pollution we had in the '80s and '90s dropped off. Some of those subject to regulatory requirements even began to question the need for TDMLs. They wondered if these programs are even necessary.”
TDML stands for Total Maximum Daily Loads. It is a measure imposed by the Florida Department of Environmental Protection (DEP) in compliance with a federal court order meant to limit the amount of nitrogen and phosphorous that enters the lagoon and other impaired water bodies.
Steward says the period of natural restoration began in the late 1990s, with the onset of a period of low rainfall.
“There were some pretty severe wildfires back in 1998 when moisture was low that mark the beginning of the period,” he said. “Improvements lasted up until around 2010.”
During that 12-year stretch, 20 percent less rain fell on Indian River County, which meant 20 percent less runoff laden with fertilizer residue and other pollutants. Low rainfall also reduced leaching from the septic tanks into the estuary-bound groundwater flow.
With a lower volume of nutrients entering the lagoon, the algae that feeds off of nitrogen and phosphorous thinned out. That made the brackish water that supports 4,000 life forms clearer, letting more sunlight shine on the seagrass meadows, which thickened and extended out into deeper water.
The process of clarification was supercharged in 2004 when hurricanes Frances and Jeanne blew through.
Even though the hurricanes brought heavy rainfall, which briefly increased surface runoff, other positive effects were more powerful, according to Steward.
“The 2004 hurricanes sliced through basin near the southern end and came up parallel with the lagoon through Brevard and Volusia counties,” he says. “The wind and waves stirred up the water. There was some scouring and all the junk on the bottom whirled up into the water column.
“At the same time, there was a powerful oceanic storm surge. Seawater flooded in, rapidly raising the water level in the lagoon, and then flooded back out just as quickly. All the stuff stirred up in the water column was flushed out in the downfall of the storm surge, leaving the lagoon cleaner than it had been in our experience.”
Seagrass responded dramatically and the period of self-congratulation and doubt about the need for regulation set in.
DEP came up with a basin action management plan that says counties, cities and water districts do not need to do anything else to reduce nutrient loads because conditions in the lagoon are improving.
The good mood lasted up until 2011 when the now infamous superbloom of oxygen-consuming algae exploded in the northern lagoon, killing 44 percent of the seagrass in eight months and ushering in a period of rapid decline in lagoon health that continues today.
“In total we have lost two-thirds of the seagrass between Vero Beach and the northern end of the Indian River Lagoon," said Lori Morris, another St. Johns scientist who spoke at the Harbor Branch symposium. "For some reason, Indian River County was the hardest hit area.”
Steward says there was one main human effort that contributed to restoration of the estuary prior to the superbloom, and that there are things people can do going forward to aid recovery in the ecosystem.
“Of all the activities we have carried out in the basin, the reduction in wastewater effluent in Indian River, Brevard and Volusia counties was the one thing that made a big difference.
“When we were developing the external nutrient loading budget back in the 1980s, it was determined that treated wastewater contributed about 25 or 30 percent of the nitrogen and phosphorous in lagoon. Now that is about 2 percent.”
Mike Hotchkiss, the Indian River County utility department capital projects manager, says nutrient reduction was achieved by cleaning up wastewater to a reuse standard and using it for irrigation.
He says there was a time when effluent was discharged into wetlands and canals but that now almost all the wastewater from the county’s three treatment plants is used by golf courses and other customers to irrigate lawns, greens and fairways, which mean the already triple-purified effluent is further filtered by the earth before it enters the lagoon.
“Facilities in Indian River County have done an excellent job of reducing nutrient flow into the estuary,” says Steward. “We estimate the county’s wastewater treatment improvements have reduced the annual flow of phosphorous and nitrogen into the lagoon by 60,000 kilograms.”
That compares to about 6,000 kilograms for all other projects combined.
According to St. Johns River Water Management models, the drought was responsible for keeping 80,000 kilograms of chemicals out of the lagoon each year while it lasted, substantially surpassing human actions.
Scientists held out hope for the lagoon, despite the futility of some past efforts and the extent of recent catastrophes.
“Nature will restore itself if conditions are right,” Harbor Branch scientist Dennis Hanisak said at the symposium.
Steward says people cannot control many of the factors needed to restore the health of the lagoon and preserve its unique ecology, but that there are three things that can be done.
“We can limit the external nutrient loading,” he said. “We know with a high degree of certainty that can do a lot for the system.”
Limiting external nutrient loading is the aim of the fertilizer regulations passed by Vero Beach, Sebastian and Indian River Shores in the past year or two, an action the county has refused to emulate, with obstruction led by county Commissioner Bob Solari who says such a regulation would undermine liberty and damage the human spirit.
Steward said dredging muck that completely covers the bottom of the lagoon in some places is a second thing government agencies can do. The muck contains large quantities of nutrients that are released under certain conditions, and removing the muck would help restore water clarity and seagrass.
“Flushing is another possibility,” Steward said, “but we need to evaluate that one very carefully.”
There has been discussion in the county about creating an opening between the lagoon and the Atlantic at Bethel Creek to accomplish an effect like that achieved by the 2004 hurricanes on a smaller scale.
Steward says that could conceivably help conditions in the lagoon but that any plan would have to be studied in great detail to make sure there would not be unintended consequences, such as a change in lagoon salinity that would further damage the ecosystem.
