THE VIRGINIAN-PILOT
Copyright (c) 1995, Landmark Communications, Inc.
DATE: Friday, August 25, 1995 TAG: 9508250652
SECTION: LOCAL PAGE: B3 EDITION: FINAL
SOURCE: BY FRANCIE LATOUR, STAFF WRITER
DATELINE: CHESAPEAKE LENGTH: Medium: 71 lines
The city has used almost half of its underground water reserve, and unless the region gets a dose of heavy rain, this source of salt-free water will be sucked dry.
Chesapeake's 318-million gallon aquifer has been pumping 3 million gallons of nonsalty water each day to about 40,000 residents.
The reserve was tapped July 23 as the city entered its worst sodium and chloride crisis in a decade.
Thursday, the water reached its highest levels of sodium and chloride since an extended drought in 1985 and 1986.
The Northwest River has been the city's main source of water since 1980, and when there isn't enough rain to flush it and winds blow steadily from the brackish Currituck Sound, saltier water is pushed into the treatment plant's intake pipes.
The aquifer was designed in 1990 as a short-term solution to the problem, storing good water in times of plenty to provide relief during droughts.
But the supply is running out - about 150 million gallons remain in the aquifer.
A sustained lack of rain may also force the City Council to impose water restrictions once the reserve is exhausted, City Manager James W. Rein said.
``The good news is, the water is reaching citizens and going where it's supposed to,'' Rein told council members in a Tuesday update on water conditions. ``The bad news is, we're a little less than halfway through the supply, and if we don't get rain in the next 30 to 45 days, we're going to have new problems.''
Once Chesapeake exhausts the reserve supply, residents who were getting some relief from the briny water - mostly in the southern Deep Creek section of the city - will join 90,000 city residents, including those in Great Bridge and Greenbrier, who now get only the salty, Northwest River water.
A thin slice of the city between Dominion Boulevard and the area of Fernwood Farms gets a blend of aquifer and river water.
Residents in Western Branch and South Norfolk receive their water from Portsmouth and Norfolk, respectively, which have no problems with salinity.
Public Utilities Director Amar Dwarkanath said the city could not afford to deplete the underground source entirely. A certain minimum level must remain, he said, in order for the city to continue to be able to inject new treated water in the future.
``It's not a tank with walls where the good water stays in and the bad water stays out,'' Dwarkanath said. As the city reaches the bottom of the aquifer, the water will be higher in salt and in fluoride because it is closer to the ground water, Dwarkanath said.
Chesapeake officials said it will take at least 2 to 5 inches of rain, and a change of winds, to send enough freshwater runoff into the Northwest River to push the brackish water back toward Currituck Sound.
Only 1 inch of rain fell last month, 5 inches below the city's average rainfall for that period.
Thursday's chloride count climbed to 965 parts per million, the highest level in a decade and nearly four times the 250-parts-per-million federal threshold for salty taste.
High levels of chloride give the water its brackish taste, but are not dangerous.
Sodium levels Thursday were at 483 parts per million, more than 24 times what doctors recommend for patients on severely salt-restricted diets. High sodium levels may also pose problems for people taking the drug lithium.
Chloride and sodium levels have not reached such heights since the droughts a decade ago, when salinity levels soared beyond 1,600 parts per million.
The salt content in ocean water is about 35,000 parts per million. by CNB