Metro Jacksonville

http://jacksonville.com/news/metro/2010-07-09/story/jacksonville-fights-algae-blooms-experimental-floating-gardens

QuoteJacksonville fights algae with 'floating gardens’

Source URL: http://jacksonville.com/news/metro/2010-07-09/story/jacksonville-fights-algae-blooms-experimental-floating-gardens

By James Cannon
Hoping to stem harmful algae blooms in the St. Johns River, Jacksonville is experimenting with a natural way of filtering out contaminants.

The answer may lie in floating gardens of specially selected grasses and weeds that serve as high-powered water scrubbers.

Initial testing by a company is being done at a retention pond near Talleyrand Avenue, and so far Jacksonville city officials are optimistic.

The problem is an overload of nitrogen and phosphorous, much of it the result of stormwater runoff from over-fertilized lawns and failing septic tanks. High nitrogen levels lead to algae blooms, which kill fish and raise an unmistakable stench. Jacksonville residents witnessed the adverse effects of nutrient pollution in May and June, when clouds of algae wreaked havoc on the river’s ecosystem.

The city has built hundreds of retention ponds over the years to control flooding and help remove pollutants before they hit the river, and launched an advertising campaign to inform the public about the dangers of over-fertilizing. But the problem remains.

“And this is only the beginning. Conditions are right for an even more severe problem,” said St. Johns Riverkeeper Neil Armingeon .

A typical retention pond removes about 35 percent of the nitrogen and phosphorous in the water before it enters the river. Natural degradation and absorption by plants are the primary tools for eliminating excess nutrients, said Dana Morton, an aquatic biologist with the city’s Environmental Quality Division.

The vegetation mats involved in the Talleyrand experiment aim to double the filtration rate â€" and save the city a lot of money.

“This has the potential to revolutionize how water is filtered in cities with high nutrient levels,” said Steve Beeman , co-owner of Beemats, the company that designed and built the garden floats.

There are currently four sections in the middle of the retention pond and a U-shaped grouping of mats around the outtake valves to give the water a final screening.

The octagonal mats are made of closed-cell foam rubber dotted with holes housing six varieties of nutrient-eating plants: Redtop, Soft Rush, Canna, Pickerel, Bur-Marigold and Arrowhead . Most of the plants can be found growing wild in Northeast Florida.

When the plants reach maturity, their root systems extend up to 2 feet under water, greatly increasing their efficiency as water cleaners.

Beemats, a New Smyrna Beach-based company, has installed enough mats to cover 12,000 square-feet, or 5 percent of the 51/2-acre pond’s surface area. Although Canna and Soft Rush absorb the most nitrogen and phosphorous, Beeman believes diversity is key.

“We need to find out which types of plants work well in different seasons and climates,” he said. “We are trying to find the least labor-intensive, most efficient and most cost-effective way to do this.”

The mats’ 30,000 plants must be replanted every year to ensure damaging nutrients are being effectively removed from future river water, he said. Once the plants are removed, they’re composted and used to fertilize top soil in the area.

A study of nutrient levels

Nutrient levels at the retention pond have been studied for the past two years so that comparisons can be made after the experiment, which began last month, runs its course.

Although Beeman’s mats have been used in other cities â€" Naples, Fort Myers and Tallahassee â€" Jacksonville is the first to have them installed as part of a statewide pollution-control experiment. To qualify, a city must study nutrient levels in its reservoirs for a specified time period. South Daytona is gearing up to try the same experiment in one of its retention ponds and will have the plant mats installed next year.

Beeman’s company isn’t being paid for the Talleyrand work, but he sees the $90,000 investment as a no-brainer.

“If this pays off and we get the reduction levels we’re hoping for, it’s a win-win for everyone,” he said.

If the vegetation mats get the job done, it could be a boon to taxpayers. It’ll cost considerably less to place them in retention ponds than to build new reservoirs, Morton said.

Adding the floating gardens to the ponds is like taking steps to improve a car’s gas mileage, he said. “Why not get more bang for the buck?”

In Florida, cities must meet state pollution standards and are assigned credits for using a range of techniques to address the problem. The mats could help increase the number of credits per pond, easing pressure to continue building the stormwater reservoirs.

Research by Sarah White, an environment and horticulture professor at Clemson University, has been encouraging. She was able to reduce nutrient pollution  by covering the entire surface of a test pond with vegetation.

The state had been creating artificial wetlands to help deal with stormwater pollution, but the experiment raises hopes of a cheaper alternative.

“Finally, technology, cost-effectiveness and governmental policy has paved the way for the entrepreneur to address these problems,” Beeman said. “It has all come together at the right time.”



james.cannon@jacksonville.com

(904) 359-4207

(http://jacksonville.com/sites/default/files/met_18VegetationMat0_0.jpg)
(http://jacksonville.com/sites/default/files/071010plantmats.jpg)

What a neat idea. Grow plants that will use the fertilizing chemicals for their intended purpose. What I thought was interesting was this:

"Beeman’s company isn’t being paid for the Talleyrand work, but he sees the $90,000 investment as a no-brainer."

Surely he's just hoping to win a high-dollar government contract but the optimist in me (small and withered though he may be) appreciates somebody giving almost a hundred grand towards an experiment to reduce pollution and the costs associated with mitigating it.

Had this idea years ago. They're not turning plants into pollution filters, they're accepting them for what they are and allowing them to be recognized for what they do.

Well now that we have destroyed and filled all of the natural wetlands in the area we are required to make artificial versions to do the same function.

Time for a big "Told you so".

I understand that they were doing this with the pond at Riverside Park but I didn't see the "floating garden" when I was there eariler this week. This is a good idea. Supporting denser growth with fewer surface parking lots would help with the river's health too I would imagine since the run-off would be naturally filtered by the ground.

They put one little float in the pond a Riverside Park.  The ducks immediately ate all of the vegetation on the top and the turtles took only a little longer to eat all of the roots.  One little float wouldn't have made any difference in the pond anyway.

Last week an air pump was installed to supply four aeration heads in the pond.  They are supposed to turn over the water in the pond about three times per day.  This has a much better chance of working than the floating plant mat given the circumstances in this particular pond.

Some sort of biologicals were added at the same time, I guess microbes to break down the nitrogenous wastes from the birds and all the bread that is thrown into to pond.  It's been a week now and so far the pond has not returned to its disgusting green goop and sewer smell.

Fingers crossed!

Green Sheen  TMDL of TMD reporting

Many more column inches required in most "River" pieces.

"The problem is an overload of Nitrogen and Phosphorous,much of it the result of stormwater runoff from over fertilized lawns and failing sepric tanks"

"Much of it...."...........how much,as a percentage?? What is the source of the balance??
Related to where the balance comes from,what about TMDL- 'Total Maximum Daily Load'  A nutrient load target deemed acceptable to a healthy river system.We are not there yet,but as per a legal mandate,we will be aspiring to reach TMDL goals.Then what?? Are we still looking for the ever demanding room for "Growth"??