(Reuters) – Florida environmentalists are hoping voters will approve a ballot amendment on Tuesday to fund the purchase and conservation of land critical to protecting the state’s water supply.

Amendment One would reserve a portion of tax money collected on real estate transactions for the next 20 years, potentially raising $648 million to buy and maintain lands in its first year, increasing to $1.27 billion by the 20th year, according to Florida’s Office of Economic and Demographic Research.

Amendment supporters hope the money can be used to buy land north of Lake Okeechobee, one of Florida’s largest fresh water sources, to help filter out pollution from the Orlando metropolitan area, as well as agricultural runoff south of the lake.

When Lake Okeechobee rises too high the Army Corps of Engineers has to pump the excess out to sea. The polluted lake’s untreated waters cannot be diverted into nearby rivers or marshes that flow into the Everglades and are lost.

“We’re wasting billions of gallons of fresh water every year,” said Everglades Foundation Chief Executive Officer Eric Eikenberg.

Other land conservation concerns involve protecting iconic Florida springs, limiting population density in fragile coastal eco-systems such as the Florida Keys, as well as beach erosion, said Janet Bowman, Florida director of legislative policy for The Nature Conservancy.

“In Florida the environment is the economy,” she said.

But opponents ranging from lawmakers to a statewide business group, say the amendment could tie the legislature’s hands should the state experience another economic downtown.

“We could very well put ourselves in a place where the legislature is forced to cut other programs or has to raise taxes during a recession,” said David Hart, executive vice president for the Florida Chamber of Commerce.

Backers say the amendment is needed because Governor Rick Scott, who has not taken a position on it, has failed to fund land programs even as the economy rebounds.

Florida Forever, the state’s land buying program created by former Governor Jeb Bush in 2000 and funded at first by $300 million in bonds, was not funded in 2011 and received only $15 million to $20 million in the last fiscal year, according to Bowman.

“If the governor and legislature aren’t going to fund it, this is the bill that will,” said Paula Dockery, a former Republican state senator who authored Florida Forever.

TALLAHASSEE, Florida (AP) – Florida voters have passed a measure that designates billions of dollars to conservation efforts over the next 20 years.

The Associated Press declared Amendment 1 passed on Tuesday. With about half the expected votes counted, the amendment had 75 percent “yes” votes to 25 percent no. It needed 60 percent of the vote to pass.

Amendment 1 will draw its funding from an existing real estate tax, and would dedicate 33 percent of it annually to conservation. That would be about a billion a year.

About half of the money will fund Florida Forever, a conservation land purchasing program that saw its budget slashed by 97 percent since 2009 dude to the Great Recession. The money was never restored after the economy rebounded