South Florida drinking water faces saltwater threat

Andy Reid in the Sun Sentinel (Florida): Summer rains can't wash away a growing underground threat to South Florida's water supply. Saltwater seeping in from the ocean keeps spreading farther west, threatening to foul underground freshwater supplies that provide most of South Florida's drinking water.

"Saltwater intrusion" in South Florida has worsened through the decades as providing water and flood control for a growing population siphons away freshwater and allows more saltwater to seep into aquifers and well fields. Ninety percent of South Florida gets its drinking water from underground supplies, most from the Biscayne aquifer. Pumping too much water from underground supplies can allow saltwater to push in from the coast.

Droughts can make saltwater intrusion worse as pumping to provide drinking water continues while rains don't come to replenish underground freshwater supplies. Now South Florida officials are projecting that sea-level rise due to climate change could increase the reach of saltwater that can make water from community wells undrinkable.

That has city and county utilities along the southeast Florida coast exploring expensive alternatives, with costs passed along to ratepayers, to avoid getting cut off from freshwater. "It is still progressing westward," Hector Castro, Hallandale Beach public works and utilities director, said. "Eventually all coastal communities will deal with this in some way, shape or form."...

Drainage patterns in South Florida as of 2005, from the US Geological Survey