Israeli Army builds new fortifications as it prepares for pullback in Lebanon

The Awali River seems more a creek than a river. It is so shallow as it snakes its way toward the Mediterranean that Lebanese often park on the riverbed. Children splash, mothers open picnic hampers, and men wash their cars.

Yet the gentle Awali has become one of the most strategic rivers in the world , for over the centuries its waters have eaten away at the rough craggy terrain. Steep, seemingly impenetrable cliffs now rise from the river.

It is behind the Awali that the Israelis are scheduled to redeploy and consolidate, taking advantage of nature's own line of defense, after withdrawal from sites more vulnerable to attack near the capital.

But the Israeli Army is not trusting everything to nature. The pace of preparations throughout the so-called ''security zone'' in south Lebanon over the past 10 days has been ''staggering,'' says a Western military attache who recently toured the area.

Capt. Mark Mendelson, the Israeli spokesman in the Mediterranean port city of Sidon, tried to play down the advance work for the still undated redeployment. ''Preparations, there's not much really,'' he said.

But the frenzy of activity is conspicuous on every turn of the narrow roller-coaster roads that wind through the mountains above the Awali. And the type of new fortifications also have serious political implications.

The level of sophisticated military installations has a look of quasi-permanence, as if the Israelis do not hold out much hope of success for the new US Middle East negotiator, Robert McFarlane, who is shuttling around the region in a bid to resolve the Lebanese crisis.

There are few hopeful signs. After Mr. McFarlane held six hours of talks in Damascus with President Hafez Assad on Sunday, the Syrians made it clear they were not willing to withdraw their 40,000 troops from Lebanon under terms the US was offering.

Al Baath, the newspaper of the ruling party, editorialized on Tuesday: -''McFar-lane's mission is not going to be any more successful than its predecessors, undertaken by other diplomats who came from Washington before.''

And in reply to reports that Mr. McFarlane is attempting, as a first stage, to win a disengagement of Israeli and Syrian forces and thus avoid a possible war of attrition, the paper said: ''We refuse the policy of partial withdrawals because it consecrates the Israeli occupation of south Lebanon.''

Mr. McFarlane then flew on to Saudi Arabia, a country he hoped would be willing to exert pressure on Damascus to compromise. But his reception in Taif was noticeably cool, according to Western diplomats, who noted that he was kept waiting for several hours before seeing King Fahd for talks that lasted just over one hour.

Until there is an agreement by the Syrian and Palestinian forces to withdraw, Israeli policymakers have indicated they will remain at the new line along the Awali River and not carry through with the next two stages of an eventual evacuation that would take them home.

That the redeployment along the Awali is not a small-scale, temporary measure is reflected in estimates from Israeli officials that the consolidation will cost more than $30 million. The Israelis will pull out of a 240-square-mile area surrounding Beirut but hold on to a zone of 1,120 square miles, just under one-third of Lebanon.

The size of the operation can first be seen on the ridges above Sidon, which will become the ''frontline'' city for the Israelis. Massive white clouds of smoke rise from bulldozers and cranes that are scalping the mountaintops, leveling them in preparation for a triangle of military facilities.

One is to be a mini-town for Israeli troops, according to an Israeli civilian engineer. Forty prefab homes, the size of railway cars and all painted the olive green and soft brown of the Lebanese mountain terrain, arrived on the day the complex was started last week. The engineer said many more would be brought in by military convoys, which clog the coastal highway, from areas to be evacuated in the Shouf Mountains farther north.

But, he suggested, the construction site a half mile away was more interesting. ''A helicopter landed there yesterday,'' he said.

The Israelis vehemently deny their redeployment is sufficiently sophisticated to warrant airstrips. ''Go ahead. Look around,'' said Captain Mendelson. ''If you can find me a place to build an airstrip, tell me. There's no place for it. And it's not worth it. It's 57, say 60 kilometers to the border. That's also a big expense. Why bother? We are here for a short time.''

Ten minutes away by car, on the road that begins the climb from the coast to the hills, a Lebanese man sitting in front of a cafe, no one special, points his finger to the top of the ridge. ''The airstrip, it's up the hill.'' How does he know? He shrugged. ''Everyone knows,'' he said. Another man changing a tire on the side of the road offered the same directions.

An Israeli military patrol blocked the entrance to the alleged airstrip, where men and machines were busily clearing a long space. ''I know nothing. I can tell you nothing,'' said an officer, reflecting the secrecy surrounding the redeployment. Well, they say a helicopter landed here the day before. ''So what, '' he responded.

From the triangle, which includes a long-established observation post and office, a recently repaved road begins. It is reportedly part of the 30-mile network of roads layered with fresh black tarmac, one of the means to cut back on the dangers of land mines planted on the old direct tracks.

At the end of the road is Karkha, an idyllic little Christian town seemingly untouched by the many internal and international conflicts that have ravaged most other corners of Lebanon.

From the peak of Karkha, the view breaks spectacularly, the hills of the volatile Shouf visible to the north, the mauve-thistled mountains of Jezzin to the south. The Mediterranean stretches to the west and the Bekaa Valley, where Syrian troops are based, to the distant east. Physically, it is like being on the edge of the world. Strategically, it is even better.

But Karkha has lost the feeling of isolation. For the IDF has now set up a base to take advantage of the view. Israeli troops would not comment on its purpose, but many residents claimed the new clearing and the houses at the side constitute a radar installation with helicopter landing facilities. ''They told us because they don't want us to worry,'' said a farmer, pointing to Karkha's latest residents. ''They want us to understand why they are here.''