RAS AL-GHAR, SAUDI ARABIA — THE drawings on the chalkboard that Saleh al-Zahrani keeps on his office wall look like a military battle plan. And in a sense, they are. In a diagrammatic web of red, black, and blue, the manager of the world's largest desalination plant has outlined his defenses against what appears to be history's biggest oil spill, now bearing down the Gulf to threaten his water intakes.
Ras al-Ghar turns 230 million gallons of sea water a day into drinking water for this desert nation. It is critical not only to Riyadh, the capital, but also to the United States and other coalition troops who take the bulk of their water supplies from desalination plants along the Gulf coast, according to a military spokesman.
As he sets up a series of floating booms in defensive formation around his plant, Mr. Zahrani says he is confident that he can keep operating, despite the spill from a Kuwaiti oil loading installation.
``The oil is over 200 kilometers [125 miles] north of here,'' he said Jan. 30. ``We don't expect it will reach us as a slick but rather broken up, in the form of tar balls. They are easy to skim ... and I don't think we will have to close down the plant.''
Other experts dispute that forecast. ``It will take several weeks before the slick turns into a more solid state,'' predicts Nisar Tawfeq, vice president of the Saudi Environmental Protection Agency.
If the slick stays liquid, and finds its way into the plant's intake lagoon, authorities acknowledge they must shut Ras al-Ghar whatever the consequences for the kingdom's water supply. US military officials refused to comment on contingency plans.
``If the oil was in quantities that had gone through the booms, if we could not skim it, then we are not going to take any chances,'' says Abdullah al Hussayn, deputy governor of the Saline Water Conversion Corporation, the agency in charge of the Saudi government's 26 desalination plants.
Bombing stanches flow
Although a coalition bombing raid last Sunday stanched the flow of oil that Iraq had been releasing from the Mina al-Ahmadi sea island terminal off the Kuwaiti coast, Saudi officials estimate that about 7 million barrels of oil have poured into Gulf waters, forming a slick about 60 miles long and 30 miles wide.
A separate slick has been detected in the northern Gulf, leaking from an oil platform at Mina al-Baqr off the Iraqi coast.
Ras al-Ghar, a massive complex of tanks, tubes, and boilers, sits in the middle of otherwise empty sand flats on the Gulf coast, about 20 miles south of the industrial port of Jubail. Dominated by 12 chimneys rising 360 feet into the hazy sky, its five water intakes - each more than 30 yards wide - suck sea water from a shallow lagoon created by artificial breakwaters.
The placid turquoise waters are now slashed by three Day-Glo-orange floating booms. Another boom in the shape of an inverted ``V'' is to be placed across the lagoon mouth to divert the oil, Zahrani said.
This is the second time he has had to protect Ras al-Ghar from oil pollution. During the Iran-Iraq war about 4 million barrels spilled from the Nowruz oil field in the northern Gulf, but that time the oil reached here only as easily collected tar balls. Though that experience gives Zahrani confidence, other experts say this optimism may be misplaced.
``No two spills are alike,'' cautions US Coast Guard Capt. Don Jensen, head of a team of US oil spill experts who arrived in Saudi Arabia this week to assist the local authorities. Captain Jensen said he fears the sheer size of the present spill might ``overwhelm'' all the defenses against it.
He challenges predictions that the slick would soon evaporate and disperse. Only 15 percent of the oil would evaporate, he claims, leaving a sludgy emulsified goo floating on the surface for several weeks to come.
That is an alarming prospect, as winds and currents carry the slick south at a rate of 10 miles a day toward desalination plants here and near Dhahran. Those plants supply almost all the drinking water for Riyadh and the Eastern Province, where most coalition troops are stationed.
The soldiers in the desert receive water from three sources, says a spokesman for the US Army's Central Command, based in Riyadh. It comes from a local bottling plant, municipal water supplies, and desalination plants on the Gulf coast.
Almost all municipal and bottled water in Riyadh and Dhahran, however, comes originally from desalination plants.
Other plants at risk
Although the US Army has brought its own desalination plants, and others are operated by the Saudi Navy, the Arabian-American Oil Company (Aramco), and local authorities, those facilities would appear to be at the same risk at Ras al-Ghar, since they are in the same area.
The desalination plant at Khafji, near the Kuwait border, meanwhile, has been closed since the town was evacuated before the war broke out, according to Mr. Hussayn. Although its tanks are full, the recent fighting in the town illustrates the problems involved in drawing water from them, and the intakes are clogged with oil, reporters who visited the plant this week said.
Everything now depends on the weather, experts say. If the winds and currents break the slick up and carry it into the middle of the Gulf, as some predict, the spill would still be an ecological catastrophe, but would pose no military danger.
If the oil starts coming ashore as sludge, however, it might claim more than cormorants as victims.