STRETCHED across the fog-enshrouded Euphrates River, the massive stone mountain that will soon be the world's ninth-largest dam stands in defiance of nature - and of protests downstream. Now nearing completion, Turkey's Ataturk Dam will be the crown jewel in an ambitious project to harness the Euphrates to produce electric power and irrigate 46,000 acres of arid land in the country's southeastern provinces.
But for Syria and Iraq, which share the waters of the Euphrates with Turkey, the implications of the $21 billion Southeastern Anatolia Project seem ominous. If the three nations fail to negotiate a water-sharing agreement by the time the Anatolia project is fully developed, Syria could lose 40 percent of its Euphrates water and Iraq up to 90 percent, according to Thomas Naff of the University of Pennsylvania, director of Associates for Middle East Research (AMER).
Such catastrophic reductions are not inevitable, says AMER, a group of international water experts. Even so, one year before its giant turbines begin spinning out electricity, the Ataturk Dam has emerged as the most disquieting symbol of the potentially dangerous competition for water that most experts believe will soon dominate the politics of the Middle East.
``The Ataturk Dam makes an implicit problem explicit,'' says Elias Salameh, director of the Water Research and Study Center at the University of Jordan. ``This is the beginning of water conflict in the Middle East.''
Under the terms of two international conventions, the Helsinki Rules of 1966 and a United Nations' convention of 1972, water rights are to be shared according to population and need, with historical allocation taken into account.
But international law also acknowledges the absolute sovereignty of nations over the resources they control.
Thus, upstream countries like Turkey insist that they are under no more obligation to give away their water than, say, Saudi Arabia is to give away its oil.
``We have no international obligations,'' says Turkey's State Minister Kamran Inan, who points instead to a 1987 ``gentlemen's agreement'' with Syria and Iraq ``to do our best not to harm our neighbors.''
Despite pressure from Syria and Iraq, Turkey has been unwilling to commit itself to a basinwide water-sharing agreement.
The case of the Euphrates also illustrates the complex synergism found elsewhere in the Middle East over water issues and other regional conflicts.
Tensions generated by the infiltration of Kurdish guerrillas into Turkey from Iraq and Syrian-controlled east Lebanon have been a major obstacle to a basinwide water sharing agreement, and have provoked fears downstream that Turkey might choke off the river in retaliation.
``We give them water, they give us terrorists,'' grumbles an official in Ankara who, nevertheless, insists that Turkey will never exploit its control of the Euphrates for political purposes.
On the other hand, reaching an agreement on water rights could pave the way for cooperation on such political issues as Kurdish terrorism and provide a catalyst to regional peace.
``Water can unite or divide the region,'' says Professor Naff. ``It can be a catalyst for cooperation and peace or for conflict.''
CONCERN over water rights in the region reached critical mass when Turkey closed off the Euphrates for one month in January to begin filling the huge reservoir behind the Ataturk Dam. It is one of 21 dams that will help irrigate an area of southeastern Turkey the size of East Germany.
Turkey compensated by increasing the flow downstream for 50 days starting late last year to blunt the effect of the closure. Meanwhile Turkish officials, members of a tripartite technical committee, have sought to allay concerns in Syria and Iraq, which will have to endure months more of such closures over the next five years before the reservoir is topped off.
But Damascus and Baghdad worry that the dam and the Anatolia project could pose big long-term problems in a region that is just coming out of the worst drought in 15 years, and that is heavily dependent on the Euphrates for irrigation to cut food import bills that in Syria alone last year claimed 6 percent of the national budget.
To meet the food needs of a population expected to swell from 13 to 22 million in 20 years, Syria plans to irrigate 100,000 acres of new land along the Euphrates. One official in Damascus calculates that because of extra demands on the river upstream, plus the rapid depletion of groundwater in Syria, the 15 million cubic meters of water needed for Syria to avoid severe food shortages by the year 2000 may be unavailable.
``It is a problem of `to be or not to be' for Syria,'' says the Syrian official of the consequences of excess demand on the Euphrates. ``You are dealing with a very hot problem.''
Matters are even worse for Iraq, which is at the end of the Euphrates water line.
Iraqi officials say that while the Ataturk reservoir is being filled, the country's electric power generation on the Euphrates could be cut by 40 percent, while water supplies to 5 million users in northwestern Iraq will be disrupted. Wheat and rice production could also suffer.
Without some form of trilateral sharing agreement, construction of the Ataturk Dam ``will have severe repercussions on the amount of water and the quality of water that reaches Iraq,'' warns Nizar Hamdoon , Iraq's deputy foreign minister.
Adding to Iraq's troubles is the prospect that Syria will trap most of the remaining Euphrates flow behind its Tabaqah Dam, reducing the downstream flow to a trickle.
The two countries nearly went to war 15 years ago when the filling of new Turkish and Syrian dams temporarily cut the Euphrates to a third of its normal volume at the Iraqi border. If Turkey and Syria implement additional development plans, led by the Anatolia project, relations could be strained to the limit.
``We're heading towards a war, unless there is intervention by the United Nations,'' grimly predicts a Western diplomat in Damascus. ``It must be done now.''