Can Sea Water Save The Lagoon?

Written for Florida Specifier, 2023

It’s been clear for a long time that the northern Indian River Lagoon in Brevard County is a heavily polluted body of water. High nutrient levels trigger blue-green algae blooms that kill fish and seagrass. Record manatee deaths in the lagoon the past two years are attributed to the seagrass die-off, which robs manatees of their primary food source.

The Florida Institute of Technology (FIT) is working under state grants to study the idea of “ocean inflow”, whereby ocean water is introduced into the lagoon in an attempt to improve water quality. The idea isn’t new, originally going back to a 2015 FIT study. But new studies now underway are expected to lead to experimental real time water inflow as soon as 2024.

According to FIT assistant professor Jeff Eble, a researcher of ocean engineering and marine science, ocean inflow is viewed as a possible way “to help stabilize the lagoon and give it a chance to heal itself.” Eble told a recent lagoon forum sponsored by the Brevard Indian River Lagoon Coalition, “we need to move some water to see what actually will happen.”

Under the plan being studied a pumping system will be created at the existing Cape Canaveral lock to pump sea water into the Banana River. The results will be studied to see if the sea water is effective at reducing nutrient levels. The Banana River is considered the worst water quality in the lagoon system, with an estimated 98% of seagrass lost in recent years.

Eble calls the Banana River the “problem child” for the lagoon. He says pollution in the Banana River contaminates the entire lagoon in Brevard County.

In earlier studies the ocean inflow concept has received mixed reviews. An original plan to leave the Cape Canaveral canal locks open most of the time was rejected by the Army Corp of Engineers. In a test period following a hurricane some years ago the locks were left open, but sand built up from the ocean currents making it difficult to eventually close the locks. 

Other FIT studies support the idea of a number of pipes and pumping stations along the Brevard beachside to introduce sea water into the lagoon. This system would be primarily in the north Brevard section of the lagoon. 

Discussion has also taken place on building a weir in the Banana River at Cape Canaveral. The weir acts as a low-rise dam, which is flooded over during high tides to release the ocean water into the river. 

The most ambitious plan is the idea of dredging an entire new inlet from the ocean to the lagoon in Cocoa Beach, just north of the Patrick Space Force base. While a previous FIT study shows the inlet would definitely improve flushing of the lagoon, that idea would involve huge expense, and has received vigorous push back from scientists and marine experts.

Leesa Soto is Executive Director of the Marine Resources Council in Palm Bay. “Everybody wants to say open an inlet and ‘ta-da’ the water quality will improve. I don’t think that’s true.”

She says a two-way flow of water, like an inlet, could harm the off-shore reef system because of the high level of nutrient pollution that would outflow on the tides from the Banana River.  She indicated the one-way pumping idea being studied by FIT is worth a look. “It’s important to do the study, if only to put to rest the ocean inflow concept.”

Aaron Adams, Senior scientist at Harbor Branch Oceanographic Institute at Florida Atlantic University, says ocean inflow ignores more important efforts to stop lagoon pollution at its source. That means reducing polluted storm water runoff, septic tank leakage, and fertilizer contamination.

Adams says ocean inflow is only designed “to take pressure off policy makers.” He says “the only way to fix the problem is to fix the causes.” He says the Brevard Save Our Indian River Lagoon (SORIL) program is working and needs to continue long term.  

A special ten year sales tax approved by Brevard voters (SORIL) is funding projects that attack the source pollution problems mentioned by Adams. Since the tax started in 2017 Brevard County has collected more than $250-million toward lagoon cleanup projects. They range from hooking up septic systems to treatment plants, dredging muck from the lagoon bottom, and installing baffle boxes to filter stormwater runoff. Even nature’s natural water filters, oysters and clams, have been reintroduced into the lagoon. It may be showing some progress.

“Right now sea grass is rebounding, water quality is best we’ve seen in a decade, all without pumping in sea water,”  says Dr. Duane DeFreese, Executive Director of the lagoon’s National Estuary Program. He says the real challenge is stopping the polluted water from getting into the lagoon in the first place. “There are no silver bullets….we have to see the science” before making decisions.

The lagoon is part of the St. Johns River Water Management District. The district’s senior scientist, Chuck Jacoby, said via email there is no quick solution to the lagoon’s problems. Fixing the lagoon “will need to be done through a variety of avenues, including the numerous projects that are ongoing throughout the lagoon, help from the local community in reducing their impact, and innovative projects like those being conducting at the Florida Institute of Technology (FIT).”

Some opposition to the ocean inflow idea also comes from the fishing community, which contends introducing salt water into the lagoon will destroy the ecological balance and threaten marine life. 

Fishing charter Captain Frank Catino, a former mayor of Satellite Beach and a member of the National Estuary Program advisory board, says “a lot is unknown.” He expressed concern on how sea water would mix with the brackish water of the lagoon, the natural habitat for the fish. “I want to hear from the marine biologists on that. Science is the key to this.”

The Brevard Indian River Lagoon Coalition has been advocating for clean up efforts in the lagoon since 2017. Chairman Craig Wallace supports the study, but not the inlet idea.

“The Coalition is always looking for science-based lagoon restoration solutions. The Florida Tech Lagoon Inflow trial project piqued our interest because it is a controlled method of using ocean water to mitigate the lagoons pollution problems, without cutting an inlet which would have a significant impact on lagoon marine life.”

So the study continues, and as Dr. Eble said, it’s time to move some water to see what happens.