SFWMD limits saltwater intrusion as utilities shift to Floridan Aquifer for 2050 demand

SFWMD limits saltwater intrusion as utilities shift to Floridan Aquifer for 2050 demandThe South Florida Water Management District's latest five-year saltwater interface mapping shows minimal inland movement in the Upper East Coast, validating regional strategies to cap surficial aquifer withdrawals ahead of a projected 36% population increase.

SFWMD's 2024 mapping project found no significant movement of the saltwater interface in Martin and St. Lucie counties, aided by the surficial aquifer's low permeability.

Future municipal water demand for the region's projected 470,000 residents by 2050 is being entirely met by new wells drilled into the deeper Floridan Aquifer system.

Targeted use of remediation wells by local utilities has successfully pulled the saltwater front back toward the coast, with chlorides dropping from over 200 mg/L to below 100 mg/L in key areas.

A 50-year Water Supply Vulnerability Assessment focusing on the surficial aquifer will be completed by the end of 2026 to guide further adaptation strategies.

The South Florida Water Management District (SFWMD) has largely halted the inland progression of the saltwater interface in its Upper East Coast planning area, according to data presented at a June 18, 2026, stakeholder meeting. The district's 2024 saltwater intrusion mapping update for Martin and St. Lucie counties showed minimal movement of the 250 mg/L chloride isochlor compared to 2019. Lead Hydrogeologist Stacey Coonts attributed the stability to the lower permeability of the local surficial aquifer system and a strategic shift in municipal water sourcing. Although the region's population is projected to jump 36% to over 470,000 by 2050, Coonts noted that "any of that future demand is getting met by wells being drilled in the Floridan Aquifer system and no new wells for the surficial aquifer system." Beyond shifting new withdrawals to the Floridan Aquifer, active aquifer management has proven effective. Resiliency Project Manager Karin Smith highlighted a utility success story where remediation wells successfully pulled the saltwater front back toward the coast. By pumping the advancing saline water and discharging it to coastal wetlands, the utility reduced chloride levels in its supply wells from over 200 mg/L to consistently below 100 mg/L. The district is continuing to monitor long-term threats to the region's water supply, including a projected one-foot sea-level rise by 2050 based on NOAA intermediate scenarios. Smith indicated that a 50-year Water Supply Vulnerability Assessment focusing on the surficial aquifer will be completed by the end of 2026 to guide future adaptation and infrastructure strategies. The mapping and resiliency data will feed into the 2026 Upper East Coast Water Supply Plan update, which outlines demand projections through 2050. Plan Manager Chad Brcka stated that the full draft plan will be posted for public review in late summer or early fall, with final governing board approval targeted for November 2026.