- March 29, 2024
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What do you do when spray treatments don't get the spots out?
That's the question Heritage Harbour South Community Development District supervisors are asking as they consider ways to clean up ponds that have recurring problems with algae, water lettuce and other issues. Monthly spray treatments are not solving the problem.
Over the last month, Josh McGarry, sales manager with Aquatic Systems, and his team analyzed ponds 20, 24 and 39, because they have had recurring problems.
"Normal treatments should control these ponds for longer amounts of time than what we've been observing," McGarry said. "We're trying to determine the underlying issue."
The ponds have elevated levels of nitrogen and phosphorous,which may be due to fertilizer runoff, stormwater from a surrounding watershed, grass clippings and other landscape debris, McGarry told supervisors at their Nov. 3 meeting.
Nitrogen and phosphorous are found in fertilizers.
Pond 39 also has high levels of ammonia.
McGarry hasn't noticed as many grass clippings in the ponds, though, so he suspects cutting the grass too closely to ponds isn't the main source of the pond scum.
An immediate treatment, which is financially covered under Aquatic Systems' contract with Heritage Harbour, is to treat the ponds with Aluminum Sulfate, which removes phosphorous from ponds but makes them uninhabitable.
McGarry worries the ponds will build a resistance to chemical treatments over time.
"We can keep throwing chemicals at these ponds, but eventually they will create resistance to herbicide," McGarry said. "If that happens, it could lead to significant financial increases in the future."
If the ponds become immune to spraying and other temporary fixes, a long-term option could be an aeration system.
Heritage Harbour might consider a diffused aeration system that runs on electricity and introduces air to the pond from the bottom.
District Manager Greg Cox worries the system would become costly to set up and maintain. "We would have to get a meter and connect to a power source," Cox said. "We're looking at a minimum of $5,000 and annual utility costs of more than $1,500 just for maintenance."
But supervisors don't want to wait for too long, as they address other more time sensitive projects, such as road maintenance.
"Maybe we can focus on one pond per year," CDD Chairwoman Michelle Patterson said. "I don’t want to turn around in 10 years and see junk in 30 of our ponds. I don't want this to take priority over roads, but we need to start thinking about these ponds."
Contact Amanda Sebastiano at [email protected].