The South Florida Water Management District is getting into the billboard business and has picked a company owned by a former board member and former business partner of the executive director to build digital signs on its lands.

The contract between the district and Florida Communication Advisors, owned by former board member Harkley Thornton, comes after Tallahassee lawmakers enacted a funding bill with a last-minute provision to allow — and recommend — “public information systems” on land owned by the state’s five water management districts.

Once the 2012 law passed, the South Florida district moved swiftly to award contracts to FCA and another firm.

Environmentalists and even some of the district’s board members have expressed dismay that its land will be used for ads.

“We’re about flood control and it just seems we’re taking on this issue and this responsibility in hopes we might make a few dollars,” governing board member James Moran said at meeting in December. “In all due respect to folks here in the sign business … it’s not the business of the South Florida Water Management District.”

Just who was behind the measure remains a mystery but several things are known:

• Thornton not only has ties to the district and its executive director but also is a close friend of former House Speaker Dean Cannon, who was in charge when the bill passed.

• Public records do not identify who slipped the billboard provision into the funding bill.

• Neither the lobbyist for the Florida billboard industry’s trade association nor the district’s legislative director say they knew about the billboard initiative before it passed.

• Nowhere in the law does the words “billboard” or “sign” appear. Instead, the phrase “public information system” is used.

After the bill passed, district staff briefed the board without mentioning billboards and instead focused on the potential profit and public awareness that could be raised by displaying public service announcements about district services, drought restrictions, flood warnings or Amber Alerts.

But the board learned in December that under the proposed contracts, such announcements would be placed on the billboards as little as 5 percent of the time, with 95 percent allotted to commercial ads.

The district’s cut remains under negotiation but officials say they hope for at least 15 percent of the revenues.

Thornton is an Orlando billboard executive who also has outdoor advertising companies in Ohio and Louisiana.

As recently as 2011, he was a business partner of Melissa Meeker, the district’s executive director, who previously served with him on the governing board.

He also is a Republican fundraiser and was chairman of Cannon’s political spending committee in 2010, the Florida Liberty Fund.

Thornton said he knew of no backroom deals in getting the law passed or favoritism in the contract. He had been off the governing board since 2008, well beyond the district’s two-year ban on doing business with the district. .

“I haven’t done anything with the district in five years, and to insinuate I’ve done something wrong isn’t fair,” Thornton said.

The lobbyist for the Florida Outdoor Advertising Association, Pete Dunbar, said that the industry group wasn’t aware of the billboard provision until after the bill passed.