ANNA MARIA – The City Commission is considering committing $50,000 in federal American Rescue Plan (ARP) funds for a nutrient removal project.
At the request of Commissioner Robert Kingan, a potential nutrient removal project was discussed in general terms on Feb. 23. Kingan previously suggested the commission hear from the city’s contracted engineers about alternatives to the $50,000 clam and seagrass restoration project proposed by restaurateur and businessman Ed Chiles and his restoration project associates.
The commission has not made any final decisions regarding how the $55,000 in ARP funds earmarked for an environmental/water quality project will be spent.
Wednesday’s discussion began with Mayor Dan Murphy noting the city has spent millions of dollars in the last several years installing vertical infiltration trenches – many of which are located in city rights of way alongside the streets of Anna Maria.
Murphy said the infiltration trenches help improve drainage, but their primary purpose is to filter nutrients and other pollutants from rainwater eventually discharged into Tampa Bay, Anna Maria’s residential canals and other bodies of water.
The limestone-covered trenches are filled with granite rocks and man-made filtration mesh that help filter the rainwater that passes through the trenches and into the city’s stormwater system and the soil and groundwater below.
Murphy noted that in addition to the cost of installing the trenches, there’s also the ongoing cost to maintain them – which he believes is a good investment, even though the periodic maintenance needs increase as more trenches are installed.
Engineering insight
Participating in Wednesday’s meeting by phone was Quinn Duffy, project engineer with Infrastructure Solution Services. He provided the commission with his insight on the effectiveness and value of infiltration trenches.
Duffy said the city’s past two phases of infiltration trench projects, and a current third phase, have been paid for by equal cost-sharing funding cooperatives with the Southwest Florida Water Management District at a total shared cost of slightly more than $2 million.
Duffy said the city has installed tens of thousands of linear feet of infiltration trenches. He said the trenches collectively remove about 600 pounds of nitrates per year, 107 pounds of phosphorus per year and have removed about 9.3 tons of suspended sediments. He said infiltration trenches remove 50-60% of the nutrients that pass through them, which he feels is a good return on the city’s investment.
Infiltration trenches cost an average of $63 per linear foot, he said, which are a cost-efficient means of treating stormwater on an Island that, in some places, has an elevation of three feet above sea level. He also said there are more costly and complicated stormwater treatment and drainage methods the city could explore.
Commissioner Jon Crane opposes the proposed clam restoration project because he’s not convinced clams filter red tide organisms and other harmful elements from the natural waters to the degree that Chiles and others claim.
“We’re charged with spending federal taxpayer money to do something good. The clams may or may not be good, but right now there’s no proof. I would rather put money into something we know works,” Crane said.
Crane asked Duffy if he had any insight on the effectiveness of clams in terms of water filtration.
Duffy said he’s aware of studies conducted around the state, especially those conducted by the University of Florida. He said it would be possible to use those studies to compare the costs and benefits of a clam restoration project versus an infiltration trench project. He said the number and size of the clams would need to be factored into that comparison.
Duffy said infiltration trenches filter the water before it reaches the bay and other natural waters, while clams help filter the water they live in. Without doing more research, Duffy would not speculate as to the effectiveness of clams versus infiltration trenches.
Commissioner Mark Short noted the commission recently doubled the annual stormwater fees assessed to Anna Maria property owners. Those fees help fund stormwater and drainage improvements and maintenance.
Kingan made a motion to use $50,000 in ARP funds for a project that uses methods proven to remove nutrients, but his motion fell by the wayside without a vote as the discussion continued.
Commissioner Deanie Sebring expressed continued support for the clam restoration project. She said $50,000 is a “drop in the bucket” and the city should do something to help clean the local waters, even if the proposed project is experimental in terms of proven results.
Jim McDaniel serves as The Center of Anna Maria’s director of development. In recent years, The Center has embarked on environmental efforts that included mini-reef installations as part of its ongoing “Go Green” campaign. During public input, McDaniel said he is on a clean water committee in Holmes Beach and he encouraged the commission to consider all options.
“Doing the ditches is so important, but I don’t see it as binary. I don’t think it’s one or the other. I stopped using ‘but’ when I write and I change it to ‘and.’ Try it. I think we need to do this and this and this. Together, we come up with better solutions,” McDaniel said.
Wednesday’s discussion concluded without any decisions being made and Murphy said the ARP project funding discussions would continue at a future meeting or meetings.
Related coverage
Marine biologist opposes clam restoration project
Decision still pending on clam, seagrass restoration funds
