Here’s something to make the one percent boiling mad: Try putting a big warehouse for regular rich folks’ boats in their backyard.

And if that backyard also happens to be a much-loved, historic and ecologically sensitive park?

Sit back and watch the sparks fly.

A plan by Miami-Dade County and famed former Miami Dolphin Nick Buoniconti and his son Marc to erect an $18 million, five-story dry-stack building for 360 powerboats in Matheson Hammock Park’s marina has run into a veritable buzzsaw of opposition from its Coral Gables neighbors, including multi-millionaire HMO entrepreneur Miguel “Mike” Fernandez and his Gables Estates neighbor, Miami Heat President Pat Riley.

Fernandez — who paid $21 million for a house on a point of land overlooking the tranquil bayfront park and tore it down to build a massive mega-mansion — is bankrolling an opposition campaign that has the incensed Buonicontis, whose partnership won a competitive bid to build and manage the boathouse for the county, up against the ropes.

Complaining that he would hear noise generated by the operation and see the building’s roofline from his house, which sits 4,000 feet across an inlet from the park, Fernandez has hired a PR. firm, two prominent zoning attorneys, a traffic engineer and a noise expert to fight it. He also created a web site with a video ripping the plan that has generated 4,000 anti-boathouse petitions. Last week, Fernandez and several allies filed suit against the county.

Elected officials in Coral Gables, which has zoning jurisdiction over the county park because it lies inside city boundaries, have been deluged with hundreds of angry letters and emails, including an impassioned plea from Riley, who wrote to Coral Gables Commissioner Ralph Cabrera that he felt “like someone kicked me in the gut’’ when he found out about the plan.

At a meeting last week in neighboring Pinecrest, where the village council is weighing a resolution opposing the boathouse, several people vowed to lie down in front of the bulldozers should the project be approved, a tactic previously employed by some Pinecrest residents opposed to a new sidewalk. The vehemence has surprised even some veteran Gables politicians accustomed to fierce planning scraps.

Fernandez says he’s just trying to protect a valuable public asset from out-of-scale, out-of-place development.

“I’m not a spoiled brat. I made my way here through years of hard work and sacrifice to enjoy a certain quality of life,’’ Fernandez said in an interview. “But this is not about me. This would change the character of that park forever. It doesn’t fit here. It is not Black Point Marina.’’

Stuck in the middle is Miami-Dade Mayor Carlos Gimenez, a resident of nearby south Coconut Grove who keeps his boat in a Matheson wet slip and who represented the area as commissioner. He said through a spokesman that it would be “premature’’ for him to intervene in the debate.

The Buonicontis and their development team acknowledge the boat building is large and that concerns about noise, traffic and its impact on the low-scale, 80-year-old park are reasonable — concerns they say they are addressing as they refine a conceptual plan that’s not yet in final form. They say they expect to submit a formal, detailed plan to Coral Gables and county and state environmental regulators later this year.

But they say Fernandez and some other critics have gone too far by insinuating that their team tried to evade public scrutiny and misrepresented the project’s scope. Instead, they say, it’s Fernandez who has engaged in “scare tactics’’ by exaggerating the project’s impact.

“I feel I’m getting railroaded by someone I don’t even know with flat-out-false statements,’’ said Marc Buoniconti, who gained renown as co-founder for the Miami Project to Cure Paralysis after he was left a quadriplegic in a college football game. “But this is not Mike Fernandez’s private marina. This is a public marina, and the need for this facility is huge. What about people who want to take their family out on their boat on a weekend and don’t have a megayacht tied up behind their house?’’

The Buonicontis and their partners, dry-stack storage developer and operator Aqua Marine, bested four competitors for the contract, which was approved unanimously last July by the county commission in an advertised public hearing. No one from the public spoke at the hearing, records show.

Under the terms of the contract, the Buoniconti partnership must get its plan through the Gables’ famously picky and lengthy public review process. That means, Gables officials told the county in a 2008 letter, it must go to the city’s board of architects, its planning board, the historic preservation board and, finally, undergo two votes of the City Commission.

“The notion that we would be trying to sneak anything through is silly,’’ said the Buoniconti group’s lobbyist, Eston “Dusty’’ Melton.

A handful of Gables residents, including former mayoral candidate Gonzalo Sanabria, have strenuously opposed Miami-Dade’s intention of adding dry-storage stacks to Matheson since at least early 2009, when the idea first surfaced publicly as the city turned down an unrelated county parks department application for a new dockmaster’s building at the park. But it was only after Fernandez launched his campaign in December that the dry-storage issue caught fire.

If anything, though, the fate of the dockmaster building suggests how hard it may be for the Buonicontis to get their plan past the Gables. The city preservation board rejected the dockmaster building as too tall for the park at 55 feet — the same height as the proposed boathouse. Though some critics claim the Buoniconti plan is just a new version of the dockmaster proposal, the two are substantially different. For one thing, the boathouse is far larger.

The sharpening conflict has claimed one casualty. To design the building, the Buonicontis hired Gables architect Richard Heisenbottle, a well-regarded specialist in historic preservation who also designed the Shake-A-Leg marine facility in Coconut Grove, and who was at the time chairman of the Gables historic preservation board. Rules allow board members to work on proposals that come up for panel approval so long as they recuse themselves from debating or voting on them.

But Heisenbottle participated in what he and Melton described as informational meetings on the storage plan with two city commissioners before registering as a lobbyist in September. That earned him a slap from the county ethics commission, which investigated after the online Coral Gables Gazette published a column criticizing the architect. The commission did not sanction Heisenbottle, but the architect resigned from the board in January after what he characterized as a campaign of “ignorant babble’’ by critics of the Buoniconti plan. He remains on the development team.

The plan does have its supporters.

Since winning the contract, the Buonicontis have been diligent about presenting their conceptual plan to neighborhood groups. They have letters of support from the associations at Deering Bay and Cocoplum, and a positive letter outlining no objections but seeking more information on traffic impacts from Snapper Creek Lakes.

Tom Abraham, a resident of Old Cutler Bay whose home fronts the narrow canal that bounds the park’s northern edge, says he’s shouting distance from the proposed building. But he sees a need for it so long as it’s sensitively designed, especially since the Gables doesn’t allow residents to park boats in their driveways or yards.

“I know there’s some guy raising a stink about this, but he’s full of it,’’ said Abraham, speaking out at the request of the Buonicontis, who are family friends. “Those of us who live on the water don’t have the right to deny that access to others. It’s not just for multi-millionaires.’’

Gables Estates homeowners initially also had no objections, but retracted that position after Fernandez complained.

Since then, a combined group of residents from Gables by the Sea and Pinecrest by the Sea, a bayside sliver of the incorporated village south of the park, voted to oppose the project, citing concerns about its effect on homeowners’ property values as well as noise, increased auto and boat traffic and environmental impact on the popular park, widely regarded as one of the scenic jewels of the county’s extensive parks system.

When it opened in 1930, Matheson Hammock was the first county park, launched with a donation of 80 acres by William J. Matheson with the stipulation that it be used “to preserve... wild and natural beauty.’’ Through subsequent acquisitions it eventually grew to over 600 acres, most of it mangrove-ringed wetlands. The core of the park known to most users, including the marina, the rustic stone buildings and the famed atoll beach, were built mostly by hand by the Depression-era Civilian Conservation Corps, which also dug out the park’s artificial harbor.

By 2000, county parks officials say, the park’s marina and launch ramps, like those at other public parks, had reached capacity amid increasing demand by boaters. Over the next few years, a series of studies and surveys reviewed by The Miami Herald made a case for expansion of dry storage and wet slips and identified Matheson Hammock and Haulover, in north Miami-Dade, as candidates.

The studies found Matheson has room for growth and a nearby concentration of boat owners, and is not a breeding or congregation site for manatees. A traffic analysis also commissioned by the county concluded that Old Cutler Road, the busy, tree-lined, two-lane roadway that’s the main point of access for a string of affluent, gated bayfront communities, could easily handle the additional traffic generated by 300 dry slots.

Moreover, the study — like the Buonicontis — suggests that additional dry storage could ease frequent traffic backups on the Matheson entrance road and Old Cutler because some boat owners would choose to keep their boats in the facility rather than tailoring them in, a proposition to be further tested in new traffic studies.

“We would not have moved forward had we not spent years studying it,’’ said Kevin Kirwin, an assistant county parks director.

The parks department, however, appears not to have analyzed the effect of such a large structure on the low-key park’s look and feel, or held any public forums to explore community sentiment before advertising for proposals.

Assertions that the plan would not worsen local traffic have been greeted by jeering scoffs from the critics.

The proposed dry-stack boat building footprint, about 500 feet long and 150 feet deep, would occupy the site of a scruffy, fenced lot that now serves as the marina’s dry boat storage. Space won’t come cheap: Monthly rents would run from $828 to $1,080, depending on boat size, with some of the revenue going to the county.

With boats up to 50 feet in length stacked four high, the new building would more than double the marina’s capacity. The current trailer lot, which the county wants to move elsewhere, has 71 spots to supplement the marina’s 230 wet slips.

Making space for the footprint, parking and creating water access for the building would require dredging up what the Buonicontis say are small amounts of mangroves and, possibly, some upland vegetation behind the structure, actions they say would have to cleared by environmental regulators and likely require mitigation.

Because the Gables code required the building to be masonry, and not the usual metal panels, Heisenbottle proposes wrapping it in concrete perforated and textured to resemble limestone, draping it in ivy to blend in with its surroundings, and lighting it dramatically in the evening.

To allay neighbors’ concerns, the Buonicontis also propose camouflaging the roofline, which would protrude some 15 to 20 feet over the Matheson treeline, with a row of royal palms. To kill noise, they would also install mufflers on the forklifts, forgo the required beeping backup signals by hiring flagmen, and conduct all boat washing and maintenance inside the concrete building. That would have the advantage of containing oil, wastewater and suds that now go into the ground or the bay, they say.

Fernandez says he doesn’t believe them, just as he says he can’t understand why the county would propose a 55-foot-tall building when the Gables limited the height of the chimneys on his new house to 35 feet.

“Why would you employ people with flags? That’s b.s. and I don’t buy it,’’ he said. “I don’t like being misled.’’

Frustrated, Buoniconti suggests Fernandez is just suffering from building envy.

“It wasn’t until Mike Fernandez got wind of the fact that our building is going to be bigger than his house that he got out his checkbook,’’ he said.