Senate saltwater intrusion study bill flows out of final committee

Flooding in Miami — resistance is futile. Image via Miami Herald.

The combination of dilapidated water and sewer systems with sea-level rise and flooding in coastal cities and towns make for increased concerns over saltwater intrusion. 

Figuring out where those problems are and the extent of the danger they pose is the aim of legislation approved by the Senate Committee on Appropriations this week.

A Senate bill (SB 734) opens up Resilient Florida grant funding to go toward coastal counties so those governments can authorize and complete saltwater intrusion vulnerability assessments.

“It is critical that more-specific studies be conducted as they relate to sea-level rise impacts, particularly in the state’s most vulnerable coastal communities,” Boca Raton Democratic Sen. Tina Polsky said. “The threat of saltwater intrusion requires that coastal municipalities and utilities be adequately prepared to mitigate this threat through fresh water supply management.”

There was no debate or public testimony on the proposal, which now heads to the full Senate.

Each vulnerability assessment would have to include looks at the county’s primary water utilities, projections of saltwater intrusion over the next decade, an analysis of the costs to relocate affected freshwater wellfields, and maps of the county’s freshwater wellfields, along with the latest saltwater intrusion impact lines.

The Department of Environmental Protection (DEP) would compile these and add them to the state’s Comprehensive Statewide Flood Vulnerability and Sea Level Rise Data Set, providing that information to the public online.

Counties with fewer than 50,000 people wouldn’t be required to cost-share on the grants, but for the others, DEP would provide 50% cost-share, up to $250,000.

“When an aquifer is contaminated by saltwater, it must either be treated to remove the salt — a costly process — or another source of freshwater must be found,” according to a Senate staff analysis.

“Public water supply utilities may shut down a well if it becomes too salty. Utilities with wellfields near the freshwater/saltwater interface that do not have an inland wellfield, have not developed alternative water supply sources, and have limited ability during a drought to meet user needs through interconnects with other utilities are considered more vulnerable.”

There’s also the flooding issue.

“Because saltwater is denser than freshwater, an aquifer can become stratified with a layer of freshwater on top of a layer of denser saltwater below,” according to the analysis. “When sea-level rise acts upon an aquifer like this, it can cause the freshwater layer to rise in response. This can cause flooding as the top of the water, called the water table, gets closer to (the) ground surface.”

Of course, saltwater going where it’s not expected damages and kills off vegetation that’s not salt-tolerant, an environmental problem generally and an agricultural problem in particular.

“We do a lot with resiliency, and that’s really important, but I believe this is the only bill that affects actual drinking water quality,” Polsky said.