At least 200 individual land owners now know Orange County needs to buy a total 750 acres of their wetlands before it can break ground on a $750 million, one million-sf expansion of the Orange County Convention Center.

The South Florida Water Management District is ordering the county to spend about $7.75 million to buy the land so that neighboring endangered species such as the osprey and gopher tortoises will continue to have a survival home. That is state law.

The county originally had planned to spend $2.5 million or $8,333 per acre (19 cents per sf) to buy 300 acres just north of the Osceola County line. The water district ordered the county to invest another $5.25 million for an additional 450 acres. That equates to $11,666 per acre or 27 cents per sf.

The district computed the additional 450-acre number using a ratio of 15 to 1. That means the county has to replace 15 acres of wetlands for every acre it destroys in constructing the four million-sf convention center on a 50-acre site. The ratio could have gone to 60 to 1 if the land was even more species-sensitive, water district officials tell GlobeSt.com.

Landowners are expected to triple their asking or appraised price, knowing the county previously budgeted $8,333 per acre, brokers familiar with the project tell GlobeSt.com.

"The county could seize their dirt, using the state's eminent domain laws, but that probably would be even more costlier for taxpayers when the county has to fight the landowners in court," Dean Fritchen, a senior broker at Arvida Realty Services Commercial Division in Winter Park, tells GlobeSt.com.

Under eminent domain laws, the county would pay a landowner the current or fair market value of the land determined by independent appraisers. If the landowner disagrees with the appraised price, he would sue the county in Circuit Court, hoping to win a higher figure.

Orange County paid Universal Orlando $15 million or $300,000 per acre for the 50-acre expansion site four years ago.

The county maintains the additional $5.25 million it will have to spend for additional wetlands purchases is still within the $750 million budgeted for the convention center expansion. The money comes out of a $120 million-a-year tourist revenue fund generated from daily taxes the county collects on the area's 110,000 hotel rooms.