MIAMI-DADE COUNTY, Fla. – It’s been a year since the unprecedented fish kill that ravaged Biscayne Bay, caused by a dramatic loss of oxygen.
Scientists now know why it happened, but fixing it won’t be cheap or fast — and as the effort to save the bay has never been more urgent, as signs point to further issues in the Little River.
Biscayne Bay had never seen the likes of the devastating mass fish kill that stretched from North Miami to Virginia Key last August.
Over five days, more than 27,000 fish and other marine animals would die, suffocating due to a sudden lack of oxygen in pockets of the bay. It was primarily caused by the overload of deadly nutrients in the canals that flow into the watershed, just like scientists had been warning about for years
“What’s become clear is that we have major pollution issues in our canal system,” said Rachel Silverstein, executive director of Miami Waterkeeper.
Right before the fish kill last summer, very high flows — higher than any time over the past 30 years — were being discharged from the Little River Canal into the bay. It’s troubling for scientists because today there are still big problems in the Little River.
“Every morning the Little River is showing us that,” said Dr. Todd Crowl, executive director of Florida International University’s Institute of Environment.
Data from a research buoy from the Institute of Environment that’s been permanently positioned near the outfall of that canal since last summer consistently shows low oxygen readings.
“The oxygen in the Little River has dropped down to about 3 millimeters per liter,” Crowl said.
It is the dirtiest of waterways. Enormous amounts of trash and debris regularly accumulate there.
The South Florida Water Management District now deploys a scavenger vessel to patrol the canal every week, scooping up all the garbage and muck on the surface. But what lies beneath is even more menacing.
“Ultimately, it comes down to the pollutants like phosphorus — that’s our ultimate issue,” Crowl said.
Recent data from samples taken by Miami Waterkeeper during the first six weeks of summer show just how polluted the canal is. Orange spots indicate high fecal bacteria contamination, and four of the biggest points are on the Little River.
“So we haven’t fundamentally fixed the underlying problem,” Silverstein said.
The biggest culprit? Aging septic tanks that no longer work.
According to Miami-Dade Water and Sewer, there are over 300 homes along the Little River currently on septic.
Many of the septic systems along the Little River are more than 80 years old, back when climate change and sea-level rise weren’t part of our vernacular. Over the years, those septics have become dislodged, spewing all that wastewater and deadly nutrients right into the groundwater that flows back into the Little River, especially after heavy rain.
Connecting those failing septics to sewer lines has been a top priority for Miami-Dade Mayor Daniella Levine Cava.
“She put out a report with the most vulnerable septics in the county, so we’re starting there,” said Irala Bague, the county’s chief bay officer.
Over the next year, the Miami-Dade Water and Sewer Department will install sewer laterals for 41 homes on septic along the Little River. And in the next two years, approximately 300 homes in the area on septic will be connected to sewer lines. Both projects are partially funded by a state grant.
“We’re honing in on the problem but it can’t be fast enough,” Crowl said.
According to the county report, of the 120,000 septic tanks in Miami-Dade, more than 57,000 are in the North Bay area.
Data shows that 56% of them are already failing and 67% are compromised to sea-level rise. Converting all of them to sewer won’t come cheap, upwards of $4 billion.
“We’re all going to need to pay for this,” Bague said.
But look at what we have to lose: It’s our environment, our property value, our water supply and our economy, driven largely by tourism.
With so much at stake, Miami-Dade Water and Sewer is also under the gun to complete a federally mandated $1.8 billion infrastructure improvement by 2026 to upgrade the county’s sewer mains and prevent more breaks from spewing millions of gallons of waste into our aquifer and waterways.
“We have no option,” Crowl said. “We have to get infrastructure put into place.”
In the meantime, to mitigate the flow of damaging nutrients entering the watershed, Miami-Dade County passed in April the toughest fertilizer ban in the state, making it illegal to fertilize your lawn during the summer rainy months of May through October and anywhere near a body of water or storm drain. That fertilizer just washes off and adds more phosphorous to our groundwater and bay, killing seagrass and feeding algae.
It’s a big win for Biscayne Bay — as long as residents comply.
There’s also the urgent issue of modernizing all the storm drains in the county.
“We have to really make sure that we’re cleaning the stormwater system so that the chemicals, the plastic, and other debris in our storm system are not getting into our waterways,” Silverstein said.
It’s another tall order that won’t just take money but years, as Biscayne Bay hangs at a perlious tipping point with the threat of another fish kill a very real possibility.
“You know, fingers crossed,” Crowl said. “We’re in better shape. But we still have a long way to go.”
Miami-Dade County is ready to activate an emergency reaction plan should Biscayne Bay show signs of dangerously low oxygen levels in the future.
The plan was developed in collaboration with Miami-Dade County, Miami Waterkeeper, FIU’s Institute of Environment, University of Miami, and other scientists working to restore Biscayne Bay. For more info on the Fish Kill Emergency Plan, click here.
Call to action
Help the county keep watch over Biscayne Bay. There are three ways to report a fish kill: