The decision reversed an announcement from July 18, when the state Department of Environmental Protection said it would order water managers to sharply reduce the amount of runoff they pump into the lake's south end.

The DEP also made an unusual confession for a major state agency: Department officials said they had erred last month, when they issued a news release declaring they could replace that pumped runoff with cleaner water from various canals.

In fact, the canal water is no cleaner than the farm runoff, and in some cases is much dirtier, DEP Assistant Director Jerry Brooks said Friday.

Meanwhile, the department said the region's drought is such a dire emergency that the lake needs water from both sources -- the farm runoff and the canals.

The reversal outraged environmentalists, who accused the department of succumbing to pressure from sugar growers who depend on the lake for irrigation.

"This is what you get when Big Sugar runs this governor's environmental agencies," said Richard Grosso, director of the Environmental & Land Use Law Center in Fort Lauderdale, which has filed legal challenges to stop the practice. "Even I was not so cynical to think they (DEP officials) would fail to live up to what they had said they would do in a press release -- that they would take the public embarrassment of caving in."

"Nothing has changed in 40 years," said Wayne Nelson, of the group Fishermen Against Destruction of the Environment. "State government still operates Lake Okeechobee for the benefit of agriculture, to the detriment of everybody else."

DEP spokeswoman Lucia Ross said Friday's decision was no cave-in, just a result of taking a closer look at the data on pollution levels.

"This action is not the result of any undue political pressure from any quarter," Ross said. "This doesn't change the department's steadfast commitment to its 30-year plan to restore Lake Okeechobee."

Malcolm "Bubba" Wade, senior vice president of United States Sugar Corp., praised the DEP's decision. But he denied that his industry has any stranglehold on the department's policies, and called Grosso's comments an insult to DEP employees.

"We have not been involved in the agency's discussions of this issue, as much as we would like to have been," Wade said.

Since late March, the South Florida Water Management District has moved 43 billion gallons of runoff into the lake from pump stations near Belle Glade and South Bay.

The DEP's order Friday allows the district to continue that pumping until the lake reaches 11 feet above sea level and stays there for 80 days. (On Friday, the lake was at 10.77 feet, just 2 3/4 inches below that target.)

And the department is allowing the district to add water to the lake from other sources, including the West Palm Beach Canal to the east and the Caloosahatchee River to the west.

On July 18, the department had said it would force the Belle Glade pumps to shut down, but would let the district keep operating the South Bay pumps and add water from the canals. The switch would "improve the lake's water quality, thereby making it even safer to drink," the DEP said in a news release issued at that time.

But on Friday, the DEP's order called the lake's low level -- not the pollution -- "an immediate threat to the public health, safety, or welfare."

Brooks said Friday that the July announcement was based on miscalculations about the level of algae-feeding phosphorus in the canal water as compared to the runoff from Belle Glade.

New calculations also concluded that the canals could not provide enough water to make up for the loss of the Belle Glade runoff, Brooks said.

Brooks said the errors appeared to originate primarily in the department's West Palm Beach regional office, which may have seized on data that didn't show a complete picture of the water the canals could provide. But he didn't know details of how the mistakes occurred and said he didn't want to cast blame.

"The agency made a mistake," Brooks said.

Brooks added that while the continued pumping will add pollution to the lake, it will be minuscule compared to the decades of abuse the lake has already suffered.

To partly counteract the environmental damage from pumping, the DEP also ordered the water district to plant 50,000 fish-nurturing bulrush plants in the lake, and pay $200,000 toward a state restoration project there. The district also must pay for any additional water-treatment costs incurred by the cities of Belle Glade and Pahokee, which draw their drinking water from the lake.