JACKSONVILLE, FLA. ? A river runs through it — and that’s a security problem for this city’s first Super Bowl.

From jet skis to cruise ships, watercraft regularly ply the St. Johns River, a federal waterway that runs right alongside Alltel Stadium.

All boats must be checked and rechecked. Ships carrying visitors by the thousands are monitored around the clock. And Coast Guard divers have to search the river on a regular basis.

NFL vice president for security Milt Ahlerich called the river “a unique aspect of this Super Bowl,” but he also downplayed the impact it had on the security plan Tuesday.

“We are very pleased with what we have seen here,” Ahlerich said. “We have complete confidence our fans, our teams, our employees will be safe — not just at the game but at the many other events.”

Although Ahlerich and Jacksonville Sheriff John Rutherford said the three-pronged approach to Super Bowl security — via land, air and sea — was the first of its kind, they also said it merely was an additional part of a detailed security plan.

Jet skis are being banned on the river, largely because of the cruise ships. Only certain private boats, whose owners won permits in a lottery, are allowed on the river. And Coast Guard divers regularly are inspecting the bottom of the ships, plus keeping other boats a safe distance away.

Also, more than 50 agencies — some federal, some state and some local — combined to develop, install and carry out the security plan.