SOUTH FLORIDA -- The $13.5 billion Comprehensive Everglades Restoration Plan was conceived in 2000 as a habitat restoration and flood control project.
But 14 years later, the authors of a congressionally mandated report say that climate change and sea-level rise, by threatening Florida's freshwater supply, are at least partially repurposing the entire enterprise.
"Rather than compromising restoration, climate change and sea-level rise provide even more incentive for restoring the Everglades ecosystem," wrote the National Research Council last month in its fifth biennial evaluation of the progress being made on the restoration plan. "Indeed, in this context the CERP can be viewed as a water sustainability plan for both the natural and human environments."
According to the National Oceanic and Atmospheric Administration, South Florida's seas have risen 9 inches over the past century. Looking forward, the Southeast Florida Climate Compact, comprised of Palm Beach, Broward, Miami-Dade and Monroe counties, is projecting 9 to 24 inches of additional sea level rise by 2060.
There is significantly less scientific consensus on how climate change will impact rainfall in South Florida. But according to the NRC report, scenarios range from rainfall increasing by 10 percent per year to rainfall decreasing by 10 percent. A decrease is the more commonly expected outcome.
Already, the rising seas have caused saltwater inundation in some coastal areas. At Everglades National Park's Cape Sable, on the far southern edge of mainland Florida, land mass comprised of organic peat communities has collapsed under the weight of the sea, spearheading a transformation of freshwater wetlands into brackish marshes.
Sea-level rise also threatens the Biscayne Aquifer, from which South Florida draws its supply of fresh water for drinking, agriculture and other uses. A joint Broward County and U.S. Geological Survey study published last year by the journal Groundwater found that sea-level rise has exacerbated saltwater intrusion into the Biscayne Aquifer underneath Pompano Beach.
Human withdraws of freshwater from the aquifer, which lower the water table and provide an avenue for the heavier saltwater to push inland, were the leading cause of intrusion.
Water demands on the aquifer are only expected to grow in the coming decades as South Florida's population trends upward. Meanwhile, the potential that climate change will reduce rainfall places the local water supply in further jeopardy, according to the NRC report.
However, a better planned and faster moving CERP could alleviate both concerns by pushing back the advancing seawater, advocates and scientists say.
"We're literally fighting water with water," said Cara Capp of the National Parks Conservation Association.
The dovetail between restoration and protecting the Biscayne Aquifer is actually fairly simple to grasp.
At their essence, the 68 projects that make up CERP serve three primary purposes: They clean the water of phosphorus pollution; they increase water storage infrastructure; and they allow for more water to flow south from Lake Okeechobee to Everglades National Park, instead of being dumped out to sea through South Florida's extensive canal and levy system.
Projects that would be built under the recently completed $1.9 billion Central Everglades Planning Project, for example, would allow water managers to direct 65 billion more gallons of water per year south, engineers estimate, while maintaining flood protection.
While those enhancements weren't conceived to counter climate change, they would do so nonetheless, said Bob Johnson, the hydrologist who heads the South Florida Natural Resources Center in Everglades National Park.
"If sea level is rising by 1 ¬½ feet, then the best way to keep that water from seeping into the coastal areas is by raising the [fresh]water in coastal areas by 1 ¬½ feet," Johnson said.
Moving CERP ahead at a quicker pace is just one of two steps that the NRC suggests should be taken to protect the South Florida water supply. The other is to more fully incorporate long-term sea-level rise and climate models into project planning.
At present, the NRC report says, CERP planners only cursorily consider sea-level projections. Further, that analysis comes only at the end of the planning process to assess the potential loss of project benefits. Rainfall change projections aren't considered at all. Projects are mainly designed based upon historical hydrological records.
Considering climate change factors at the beginning of the process could lead planners to enhance some projects and do away with others.
"The outcome of these analyses would inform future system-wide decisions of project prioritization," the report says.
Johnson said the Everglades community should revise the entire manner in which it describes CERP.
"We try to sell Everglades restoration as a habitat protection project when you can better sell it based on its water sustainability benefit -- the benefits of being able to live down here based upon water supply and flood control," he said.