Spoonbill Marsh project provides net benefit to lagoon
Indian River County this week released four years of water-quality data on its 27-acre Spoonbill Marsh project showing that the water filtered and processed by the marsh tests is consistently lower in harmful nitrogen and phosphorus concentration than the water naturally present in the Indian River Lagoon today.
Officials stand by their choice in 2009 to spend $4 million on the project instead of drilling a deep-injection well, which could have cost utility ratepayers two to three times more (Vero Beach's deep injection well project cost water customers $11 million).
The county’s permit from the Florida Department of Environmental Protection dictates that the water coming out must have a “net environmental benefit” of at least one pound of nutrients to be in compliance. According to data released a few days ago, Spoonbill Marsh consistently exceeds this goal, having removed nearly 25,000 pounds of nitrogen and more than 8,300 pounds of phosphorus from the water renewed by the marsh since the project’s inception.
Too much nitrogen and phosphorus in the lagoon, scientists say, can cause algae blooms which block out life-giving light from the sea grasses that are critical to the lagoon’s health.
“It works, it has worked and it will continue to work while the people of Indian River County enjoy the clean water being put back into the lagoon,” said Utilities Director Vincent Burke.
Technical staff and environmental engineer Chip Swindell of Ecotech Consultants compiled monthly reports sent to FDEP into annual numbers presented to the Board of County Commissioners. In the first year of operation of Spoonbill Marsh, the water coming directly from the lagoon tested as having 14,013 pounds of nitrogen and 3,150 pounds of phosphorus. The demineralization concentrate coming from the water plant tested as having 4,308 pounds of nitrogen and 122 pounds of phosphorus.
The water flowing back out into the lagoon after natural processing through the marsh had 7,729 pounds of nitrogen and 377 pounds of phosphorus – roughly half the nitrogen and about one tenth the phosphorus of the river water taken into the marsh project.
“Over the years, Spoonbill Marsh has removed tons of nitrogen and phosphorus from the river,” Swindell said.
The idea of using earth, water, sunshine, aquatic plants and even oysters as natural percolation and filtration devices to treat the by-product of reverse osmosis water treatment was, and still is, considered a cutting-edge practice. Like most things that break with tradition, the Spoonbill Marsh concept has drawn its share of detractors and skeptics from the community of scientific consultants for hire, but the throngs of migratory birds, fish and other wildlife which have taken up residence in its waters and along its banks don't seem to mind the experimental nature of their man-made habitat.
When water is pulled from the county’s 15 wells, which are dug 750 feet deep into the Floridan Aquifer, minerals and nutrients must be removed during the drinking water purification process. For every 800 gallons of drinking water produced, about 200 gallons of concentrate remains as a by-product.
It used to be a common practice to release that by-product straight into the lagoon or into a canal system, but utilities still discharging into the lagoon are on a strict timetable to find an alternative way. Vero chose to inject its concentrate into a deep well. For its North County Water Treatment Plant, Indian River County chose instead to enter into a public-private partnership with Grand Harbor to turn a degraded citrus grove that was overrun with invasive Brazilian pepper trees into an engineered, managed marsh.
Water is pumped in from the Indian River Lagoon just north of Grand Harbor, and it is tested weekly at the intake point for salinity, nitrogen and phosphorus. That lagoon water is mixed with the demineralized concentrate that is pumped from the North County Reverse Osmosis Plant near the county fairgrounds, tested at its entry point and released into the marsh to wind its way through the mangrove-lined wetland eastward back to the lagoon, where the water is tested on the way out.
Burke said it’s a bit frustrating combatting some of the misconceptions people have about Spoonbill Marsh. He pointed out that “this is not a wastewater treatment plant,” and that the concentrate piped in from the water treatment plant is very similar to river water. The purpose of Spoonbill Marsh, he said, is to increase the effectiveness of the water treatment plant, but the environmental benefits and wildlife habitat provided by the marsh are just a bonus.
“At the end of the day, the county made a bold decision and here are the results – let them speak for themselves,” Burke said.
A long-time Harbor Branch Oceanographic Institute engineer, Burke brought vast environmental, permitting and compliance experience to the county’s utility department when he replaced retiring director Erik Olson in December 2012. Olson, who oversaw the water, wastewater and solid waste departments since 2001, brought Spoonbill Marsh from concept to fruition with long-time advisor Swindell.
The county constructed a boardwalk for public access, and Burke said he hopes to open the site up to the public on a regular basis going forward so taxpayers can see for themselves what Spoonbill Marsh is all about. Currently, the Indian River Land Trust conducts periodic tours, and Grand Harbor residents also have limited access to the facility, as Grand Harbor donated much of the land.
The riverfront property was set for development, according to Swindell and Burke. “A developer had plans to turn this into a hole of a golf course,” Swindell said, gesturing to a swath of the marsh. Housing would soon follow the golf course, and another chunk of undeveloped riverfront would be gone.
“I have the philosophy of getting a net return on your investment. If you shoot it down a well, it’s gone,” he said, adding that millions of gallons of valuable water resources are lost each year, and the lagoon is not improved.
The site had some degraded citrus grove on it, but mostly it had been taken over by Brazilian peppers, which spread rapidly and choke out other vegetation. The peppers were removed – and removed again and again when they started to grow back. Then three main holding areas of the marsh where the water is pumped in were dredged, along with a winding network of canals that run through white, red and black mangroves, past installed colonies of oysters and eventually out to the lagoon. The oysters were added post-construction by former Florida House Rep. Charles Sembler, for added filtering of the water.
“There is a bevy of oyster colonies. We are on the fifth generation of oyster colonies which have propagated since the opening of the site,” Swindell said. “From the 2011 annual report the average density of oysters was approximately 2.5 oysters per square meter. From the 2013 annual report the numbers have grown to approximately 5.28 oysters per square meter.”
Wildlife counts conducted by county staff and consultants show that a total of 58 species have been observed on the 27-acre tract since 2010. The number of bird species has more than doubled from 14 to 34 species. Mammal species have also doubled from six to 12. Varieties of amphibians and reptiles fluctuate, but at least one nine-foot alligator traverses a canal, a road and a gravel parking area to get to the marsh to hunt.
Some catch-and-release fishing happens at the marsh, with snook and barracuda being among the fish species hooked by anglers. Swindell said smaller fish like the safety of the complex, finger-like root systems of the red and black mangroves that thrive on the site.
Building off the success of Spoonbill Marsh, the county is planning to open a second facility to take concentrate from the South County Water Plant. That by-product is currently being discharged into the lagoon, but soon it will be mixed with canal water, “scrubbed” using natural and engineered processes and returned to the canal system, improved in quality and nutrient content. That project is still in the construction and testing phase.