In the eastern United States, water flows from higher elevations
toward the low-lying coast. As a result, most East Coast cities
should have water to spare. "Under natural conditions, if you drew
a well even close to the coast, you'd hit some freshwater," says
Paul Barlow, a hydrologist with the U.S. Geological Survey.
But overpumping can reverse the flow, drawing salt water where
freshwater once drained. Saltwater intrusion of freshwater aquifers
is a burgeoning problem in at least nine East Coast hotspots from
southeastern Florida to Cape Cod, Mass., according to the USGS.
Hardest hit of all may be South Carolina's Hilton Head Island.
There, saltwater contamination has forced the island's largest
water utility to abandon four supply wells since 1990. It may have
to shut a fifth later this year.
"Right now the saltwater intrusion comes to a point halfway through
the island, and a lot of our water comes from the edges of that
point," says Richard Cyr, general manager for the Hilton Head
Public Service District, which serves 25,000 homes.
Traditionally in the U.S., water supply problems were largely
confined to the arid West. But whether the cause is saltwater
intrusion, overuse by cities and farms, or drought — or a
combination of these problems — threatened water supplies are
becoming more common in the East. That's especially the case in
coastal regions, where populations have soared. "Drought and
overall short-of-water supply issues have really become much higher
on the agenda in the Gulf Coast and East Coast states in recent
years," says Donald Wilhite, director of the National Drought
Mitigation Center at the University of Nebraska.
Saltwater Intrusion Comparison
The area marked in red indicates the increase of salt intrusion
along the base of the Biscayne Aquifer from 1977 to
Figures modified from Parker and others (1955), Klein and
others (1975), Hughes (1979), and Sonenshein (1997)
As of mid-July, summer 2006 appeared to be shaping up as normal to
moderately dry on the East Coast. But water supply had already
become a hot issue in several states:
• In Florida, state and regional water officials rejected a
request by Miami-Dade County to boost withdrawals from the stressed
Biscayne Aquifer to support new developments. The state later
agreed to a temporary increase while Miami-Dade worked out a plan
to increase water reuse and make other major overhauls.
• In New Jersey, Governor Jon Corzine proposed a tax of
4¢ per 1,000 gallons of water to raise money for land
preservation and infrastructure improvements to help the state cope
with water shortages. Lawmakers rejected the proposal, but the
state is proceeding with a comprehensive water-supply plan. "People
are paying more attention to it now, because people know that is it
not an endless commodity," notes Joe Mattle, supervising
environmental engineer for New Jersey's Division of Water
• In Maine, conflicts between maintaining river flows and lake
levels to protect endangered Atlantic salmon and other species
while ensuring adequate water supply for cities were on the rise.
Water supply issues are "first emerging in the coastal zone because
that's where the population pressures are the greatest," explains
Catherine Schmitt, a science writer with Maine Sea Grant and the
author of a report on the effects of the 2001-2002 drought on the
Granite State's drinking water supplies.
Freshwater Distress Areas
Accessing groundwater resources along the Atlantic coast has caused
saltwater to intrude many highly productive freshwater aquifers.
Selected areas identified by the U.S. Geological Survey (indicated
here in red) show where salt water has intruded fresh groundwater,
and where future development may cause the most stress to
Up and down the coast, water supply threats have not forced
widespread restrictions on new buildings nor spurred major price
increases — at least not yet. But they are causing regional
conflicts over water supplies and shaping public policy shifts. In
June, for example, Georgia adopted a plan aimed in part at guarding
freshwater aquifers against more saltwater intrusion along the
South Carolina border in the Savannah-Hilton Head region. The plan
seeks to reduce withdrawals from the Upper Floridan Aquifer by 5
million gallons per day by the end of 2008 — no easy task in
light of the fact that Savannah-Hilton Head lie in an area
"expected to experience the highest rates of growth in population
during the next 25 years," the plan notes.
Potential fixes range from increased surface-water withdrawals to
boosted water reuse to desalination plants. The Hilton Head Public
Service District, which has faced the issue longer than most, now
pipes in water from a mainland surface-water system and relies on
an extensive reuse infrastructure to reduce demand for new water.
All but one of the island's more than 20 golf courses now tap
reused water, says Cyr, the water manager. Despite those and other
steps, the utility is moving forward with plans to build a
reverse-osmosis plant to transform brackish water into drinking
"There's not only the issue of more water for growth; there's also
the issue of losing what you have," Cyr notes. "Growth we could
handle. It's losing one of our major wells — that we can't
handle." — Aaron Hoover