WITH U.S. FORCES, SAUDI ARABIA -- In the first days of the expected allied invasion of occupied Kuwait, trucks filled with hundreds of thousands of gallons of fuel and water and tons of ammunition and food will stream out of the massive sand walls that surround this Marine Corps fortress in the desert and snake through the battle zone, feeding the troops and machinery of combat.

Many of those same trucks will return to this base loaded with the bodies of men and women maimed or killed on that battlefield.

"This war is a logistics war," said Brig. Gen. Chuck Krulak, who has been charged with equipping and supplying the more than 80,000 Marine Corps ground forces now poised to attack Iraqi forces inside Kuwait.

The long distances, brutal desert environment and an attack plan that varies dramatically from traditional Marine war-fighting doctrine have prodded commanders in Saudi Arabia to take risks, placing "rear" supply depots closer to the front lines than most of the combat troops they are feeding and fueling.

"We're normally in the rear with the gear," said Krulak, 48.

"The commanders took the calculated risk. . . . It primarily has to do with having a very mobile battlefield and getting the supply base as far forward as possible."

The Marine supply depot would normally support amphibious assaults, rather than large-scale land attacks like the one being considered against Iraqi troops in Kuwait.

Inside the high sand and rock ridges of this forward supply base are hundreds of acres of materiel, much of it hidden by dozens of sand bunkers designed for protection from artillery fire. In the evenings, as the orange sun sets behind the western bunkers, a ghostly haze hangs over the vast compound while dozens of trucks and bulldozers move new residents into the walled city. Eventually it will be the wartime home for thousands of Marines.

On one edge of the base, Capt. Tom Hawkins is directing construction of a field hospital with more than 200 beds and more than 10 operating rooms. On the dusty building site, a neurosurgeon hammers nails into walls while nurses haul lumber and supplies for one of the hospital wards.

"Everyone pitches in, from the doctors to the engineers," said Hawkins, who counts this facility as the third field hospital he has helped build in Saudi Arabia in recent months.

"It could be pretty rough casualty-wise," said Krulak of the expected ground war. Although allied planes have pummeled Iraqi troops for almost five weeks, destroying many of their supply lines, he noted, "They've been hurt, but they still have the capability to sustain a battle for a period of time."

Some of the first Marines to cross the Kuwaiti and Iraqi borders will be mine breachers, who will face one of the most dangerous tasks of combat here. But for the moment, their "Ninja dozers" -- boxy armored bulldozers designed to plow through the minefields -- are helping build the sand berms of this supply camp.

Living and working behind many of those berms are men and women whose little-noticed and frequently dull peacetime jobs have assumed dramatic new stature here.

For example, there's bulk fuel, said Krulak, pulling up beside the depot's multimillion-gallon fuel farm. "In peacetime, nobody cares. Now, it's on the pointy edge of the spear in this environment."

High above the town's submerged command center, a Kuwaiti flag cracks in the stiff desert wind next to the Stars and Stripes. Krulak said the flag was given to him by Kuwait's ambassador to the United States, Saud Nasir Sabah, whose son attended St. Alban's School in Washington with Krulak's son.

"I told the ambassador I'd carry the flag into Kuwait with me," Krulak said.