The report from independent scientists appointed by the National Resource Council is more upbeat than previous reviews but also finds much to question in the joint state-federal effort launched in 2000.

After a dozen years, the report finds plenty of positive signs with eight projects under construction, a new $880 million state plan to clean up polluted farm and suburban runoff and efforts to reduce federal red tape that has delayed work for years.

But life in the vast interior Everglades, from tree islands to endangered snail kites, continues to decline for a lack of water, and restoration could stall again in the near future unless Congress signs off on pending projects and steps up with more money. The report finds that too much early work has focused on the edges of the Everglades, with water storage and flood-control projects intended to protect or benefit cities and farmers, while little has been done to revive the interior marshes and sloughs starving for more water.

"The key point is there is continuing degradation in ecosystems that will take decades or perhaps centuries to recover,'' said William Boggess, an agricultural sciences professor at Oregon State University-Corvallis and chair of the committee of 14 scientists who wrote the congressionally mandated analysis.

The two-year progress report from the council, part of the nonprofit National Academy of Sciences, is the fourth in a series of independent assessments ordered by Congress of a restoration plan jointly managed by the U.S. Army Corps of Engineers and the South Florida Water Management District.

Previous reports have been broadly critical of restoration efforts, particularly in 2008 when a blistering analysis found efforts paralyzed by delay, interagency turf battles, spiraling cost projections and indifferent political support. The agencies have used recommendations in past reports to overhaul plans.

The water district and the Florida Department of Environmental Protection issued a joint statement saying the report "reaffirms the significant progress that has been made, including advances in scientific understanding, while recognizing the considerable work that lies ahead."

The latest report points to an array of remaining science, engineering and money challenges for an ecological restoration project of unprecedented complexity and but also finds substantial movement over the last two years, citing "notable progress" on the eight construction projects, plus advances in science and improvements in water quality that are key to a healthy Everglades.

"There are signs of hope,'' Boggess wrote in a preface to the 210-page report.

The report was completed before the Florida Department of Environmental Protection and the U.S. Environmental Protection Agency earlier this month finalized an $880 million state plan intended to dramatically reduce the flow of farm and suburban pollution into the Everglades.

But even without the additional projects, the report suggests the $1.8 billion the state has spent on a network of pollution-scrubbing marshes is having an effect. There are signs that concentrations of the damaging nutrient phosphorus are starting to stabilize. The spread of cattails - plants once dubbed by a scientist as "grave markers of the Everglades'' because they crowd out native plants in polluted areas - has begun to slow.

The most pressing challenge, the report finds, is to move more quickly to restore natural flows to the parched sloughs of Everglades National Park and to sawgrass marshes and prairies between Tamiami Trail and the farms south of Lake Okeechobee.

Last year, agencies launched a Central Everglades project intended to speed up that work by reducing the typical planning period from six years to 18 months. An initial blueprint is expected by year's end but where funding will come from remains uncertain.

Despite a deep recession and resulting budget shortages, both the state and federal government continue to support restoration and pollution control efforts - though the report notes that future funding on the federal side is uncertain unless Congress approves major legislation that typically funds large civil works projects across the nation.

Though funding has increased under the Obama administration, restoration remains far from the 50-50 cost-share it was supposed to be, the report finds. The state has outspent the federal government - $3 billion to $854 million - on specific restoration projections since 2002. On overall Glades spending, including pollution clean-up and previously approved projects, the gap is even larger, $10.1 billion in state funding to $3 billion in federal dollars.

Boggess, who was in Washington Thursday briefing agencies and congressional aides on the report, said "We've been encouraging the federal interests to pick up the slack and focus a bit more on the water quantity.''

After 12 years and billions of dollars, "little progress" has been made in restoring the core of the Everglades, according to a report released Thursday by the National Research Council.

The report, an annual assessment required by Congress, found most restoration projects took place around the edges of the Everglades, improving water quality but failing to address the more severe problem of the quantity of water flowing through the vast marsh. As a result, there has been a continued decline of the classic central Everglades ecosystems, the sawgrass sloughs, ridges and tree islands inhabited by alligators, wading birds, snakes and panthers.

"There has been minimal progress in restoring the water flow volumes and velocities, depth, and duration that sustain the distinctive terrain of the Everglades," states the report, prepared by 18 scientists from universities and the research council's staff.

Of the 3 million acres of the original Everglades, about half has been drained to make way for farms and cities. What remains has been degraded by a system of canals, levees and pumping stations that have destabilized the natural flow of water, leaving some sections of the Everglades too dry, others too wet. The water that does arrive contains too much phosphorus and other pollutants, which fertilizes the growth of cattails, crowding out native vegetation.

The $13.5 billion Everglades restoration is a state-federal project to restore natural flows of clean water through marshes, tree islands and sloughs, improving habitat for a vast range of wildlife and ensuring water supplies for South Florida's human population.

"I think the scientists are looking at this and saying, 'Hey, time is running out,'" said Jonathan Ullman, Everglades representative for the Sierra Club. "This isn't moving fast enough, and if we really want to restore the Everglades, we have to restore the flow through the central Everglades and provide clean water."

Gov. Rick Scott and federal environmental officials last year announced plans to reemphasize the central Everglades, and the authors of the report said they were "encouraged" by this development. But they warned that time was growing short, and expressed concern about funding.

Although costs were intended to be split by the state and federal governments, Florida has so far put up $3.1 billion and the federal government $854 million.

Howie Gonzales, ecosystem branch chief of theU.S. ArmyCorps of EngineersJacksonville District, the lead federal agency on the restoration, acknowledged most progress so far has been on the peripheries but said plans for several central Everglades projects will be delivered to Congress for approval in the next two years.

These "will identify and plan for projects on land already in public ownership to allow more water to be directed south to the central Everglades, Everglades National Park and Florida Bay while protecting coastal estuaries."

The report said it could take centuries for some of the most ravaged parts of the Everglades to recover, including tree islands, ridges and sloughs and the thinning peat soil underlying the marsh.

dfleshler@tribune.com, 954-356-4535

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