The county spent millions building two artificial marshes intended in part to reduce the amount of pollution going into the Indian River Lagoon, but now a top water official says the facilities are actually increasing the flow of harmful chemicals into the ecologically sensitive estuary.
The 67-acre Spoonbill Marsh, which is supposed to treat mineral-rich effluent from the county’s north water purification plant and clean nutrients out of lagoon water that is mixed with the effluent, was built north of Grand Harbor in 2008. The West Regional Wastewater Treatment Facility marsh, built in the 1990s, is intended to remove nutrients from treated sewage effluent before it flows into the 8th Street Canal, which leads to the lagoon.
But David Gunter, who has been superintendent of the Indian River Farms Water Control District for more than 40 years, says both marshes are malfunctioning and leaking large amounts of algae-producing nitrogen into the lagoon. A series of massive algae blooms has decimated the estuary in recent years, killing seagrass and aquatic animals.
In a nutshell, Gunter says that due to faulty design or construction, the marshes are seeping nitrogen into the ground water that ends up in the lagoon. “If you add up all the nutrients from tributaries and canals into the lagoon, the nutrients in the lagoon are higher,” Gunter said. “There is another source of nutrients – groundwater – seeping into the lagoon.”
So far, the County Commission and the Florida Department of Environmental protection, which permits the marshes, have turned a blind eye to the alleged pollution. Vero Beach 32963 asked all five commissioners to comment on Gunter’s allegations, but only one responded.
Since the county and FDEP are in the business of not polluting, “understandably, they don’t want to hear about the pollution, or test for it,” Gunter said.
Gunter says there is a twofold problem at the wastewater treatment marsh. First, the county has failed to harvest aquatic plants in the marsh that are intended to absorb nitrogen from the effluent. Unharvested, the plants die and sink to the bottom of the marsh, adding more nutrients that seep into the water table, eventually ending up in the lagoon.
Over time, Gunter said, the settling ponds have built up a mucky bottom that holds life-killing bacteria that depletes oxygen in the water.
The “telltale signs” the lake has a dead, oxygen-less bottom, Gunter said, is the rotten-egg smell, gray spider-web like growth on vegetation along that part of the canal and the ammonia spike in recent samples taken.
Another indication of leaks is the rampant growth of plants in the 8th Street Canal near the treatment facility, which he said is fed by nitrogen coming from the marsh.
“The plants don’t lie,” Gunter said. “For the last 15 years that’s the first place we hit with herbicides. They need sun, water and nutrients. If we don’t remove them they stop the water from flowing.”
The second factor contributing to the pollution, besides a failure to harvest plants, is that neither the levee that separates the sewage treatment facility from the 8th Street Canal nor the 13 ponds where the nitrogen-rich plants grow were lined with clay to keep them from leaking.
Gunter says the weight of the water – millions of gallons a day – going into the interconnected ponds at the treatment facility is pressing down on the unconfined lake bottom, which is higher than the canal, and forcing polluted groundwater into the canal.
Carter Taylor, a longtime member of the Indian River Neighborhood Association’s lagoon committee, says seepage at Spoonbill Marsh has a similar cause. Along with Gunter, he contends Spoonbill’s confining capstone was breached when the large holding pond was built, enabling chemically-laden water to seep into the lagoon without going through the marsh for purification as intended.
Chip Swindell, owner and head engineer at Ecotech Consultants, designed both marshes for the county. He argued there is no problem at either facility.
The aquatic plants don’t need to be harvested because they are removing nutrients by turning them into gases, according to Swindell, emitting them into the atmosphere in a process called transpiration. At Spoonbill, most of the transpiration is through mangroves, he said. At the sewage treatment facility, most of the transpiration is through coontails, a rooted aquatic plant, “that decomposes so fast there are no nutrients,” Swindell said.
Swindell answered concerns Spoonbill is seeping nutrients into the lagoon by stating the nitrogen there is in a form not absorbable by algae.
He said he will investigate the situation at the West Regional Treatment Facility, but doubts its nutrients are seeping into the canal. “I walked the length of the canal facing the marsh and didn’t see one single seep area coming through the levee,” Swindell said.
Bob Solari, the only commissioner who responded to inquiries about lagoon pollution, refused to address Gunter’s groundwater-seepage argument. “It is beyond my ken,” he said.
Solari both agreed and disagreed with Gunter’s harvesting argument.
“Harvesting hydroponic plants – we agree – the county has long understood it is supposed to be harvesting,” Solari said, but did not state that any action would be taken. He also suggested that storm-downed mangroves the county has on occasion removed from Spoonbill Marsh was a form of harvesting.
Asked if the county will conduct tests to find out if the sewage treatment facility marsh is seeping nutrients, Solari said, “the County does not believe [the marsh] is the cause of hot spots in the canal system.”
Concerning Spoonbill Marsh, Solari said that because the marsh’s shoreline is only a tiny fraction – about “0.3 percent” – of the total shoreline, the notion it is having an effect on the lagoon “is almost silly.”
That argument seemed not to account for the fact that millions of gallons of water are pumped into the lagoon at the location each day, something that does not happen along other similar stretches of the lagoon.