Environment : Dam Unleashes Flood of Hostility : The massive project creates tension between Czechoslovakia and Hungary and angers environmentalists.

Vapor lights searing through the fog cast an eerie primrose haze over Gabcikovo’s sprawl of concrete, machinery and mud. Idle high-voltage wires sag from giant steel lattices that look like skeletons in the mist. Dirt-encrusted police cars with steamy windows guard entrances to the site--a 20-mile-long eyesore built in defiance of man and nature.

The scene at Gabcikovo, home of a massive and much-maligned waterworks, is more an international incident than a feat of engineering.

The last of the Stalinist hero projects, Gabcikovo’s builders have rerouted the Danube River, redrawn an international border, threatened the drinking water for half of Hungary and outraged the governments of Central Europe and environmentalists worldwide.

It is the biggest ecological controversy to erupt in the region since hard-line Communists were routed three years ago.

It is a major threat to peace between two erstwhile allies, Hungary and the republic of Slovakia.

It is also a dilemma for Western leaders who are being called on to decide perplexing questions that are the aftermath of revolution, such as the degree to which today’s democratic governors of Eastern Europe are obliged to fulfill the promises made by discredited leaders of the past.

Hungarians denounce Gabcikovo as a monstrous monument to the days when big meant good and industrial behemoths were testimony to technological prowess. They accuse the Slovak government of hubris and nationalist grandstanding, and Budapest contends the project is as economically unsound as it is ecologically devastating.

Environmentalists claim diversion of the Danube has disrupted a natural water-purification process, drained sensitive wetlands, flooded forests and dried up wells on the Hungarian side. They demand that the Slovak government restore nature’s status quo ante by demolishing a dam, completed less than a month ago, that redirects the Danube from its natural channel along the border with Hungary into a concrete-lined canal leading up to Gabcikovo.

However, diversion of the Danube’s flow into the bypass canal to Gabcikovo was deemed by the original project’s Communist designers to be the best way to regulate shipping as well as to harness the hydropower potential of the river. Larger ships were unable to pass through some stretches of the natural riverbed during the autumn low-water season.

So, despite Hungary’s refusal to complete its share of what was to have been a joint engineering works, Slovakia has plunged ahead and redesigned the project so that all construction takes place on Slovak territory. They argue that to drop a $1-billion investment on the verge of completion would be capitulation to environmentalist hysteria.

Mediators from the 12-nation European Community are being asked to find a solution from among the irreconcilable positions staked out by the adversaries.

The Danube River project was originally designed as an even larger complex of dams, canals and power stations that would improve navigation and produce hydroelectric power along a 100-mile stretch of the river between the Slovak capital of Bratislava and the Hungarian city of Nagymaros. Hungary and Czechoslovakia signed a treaty to build the system in 1977, when both were tightly tethered to Moscow and forced to imitate the Soviet penchant for industrial gigantism.

Environmentalists in Hungary were staunchly opposed to the project even at its inception, said Janos Vargha, head of the Danube Circle conservation group formed in 1984 to protest the dam and its ecological consequences.

Vargha contends the diversion is an ecological hazard because a reservoir being created on the Slovak side is a natural trap for harmful byproducts of the region’s polluting industries.

Danube Circle’s unrelenting challenge to the former Communist regime in Budapest played an important role in forcing the leadership to listen to the people. One of the first acts of the reform-minded government that succeeded the hard-liners was the 1989 decision to scrap the larger project and negotiate a new treaty with Czechoslovakia.

Austrian contractors were paid off with promises of future electricity supplies to compensate for their lost investment and broken contracts. But despite three years of negotiations, the Hungarian government failed to reach any agreement with the Slovak leadership and unilaterally abrogated the 1977 treaty in May of this year.

Without the power station envisioned for Nagymaros, the electricity-generating capacity of the project is minimal. Even Slovak officials concede it would supply less than 5% of the energy needs of their independence-bound country. Conservation groups claim Slovakia--due to break with the Czech lands at the end of this month--could reduce electricity consumption by 40% with moves to cut waste.

The Slovaks take a diametrically opposed view.

To deprive the completed Gabcikovo station of water to power its turbines would be to waste years of work and considerable resources, said Julius Binder, head of the Slovak government water directorate that built the power station and last month diverted all but a trickle of the Danube River to the dam.

“We put 25 billion crowns (nearly $1 billion) into this project, and to that you must add interest costs and the 12 years of other resources put in. You cannot just walk away from that kind of investment,” Binder said.

Binder disputes the doomsday scenarios offered by foreign environmentalists and accuses Budapest of spreading gossip that the project is structurally unsound.

Construction of the new channel to Gabcikovo and diversion of the river 20 miles upstream have created a long, narrow island of Slovak territory between the man-made waterway and the original riverbed. Three villages are now cradled between the empty natural basin and the dikes that hold back the diverted water.

“The local people are very much opposed to this project because the water was diverted before construction was finished on the retaining structures,” said Jan Babaj, deputy mayor of nearby Samorin. “There was a rush to finish during the low-water season, and we’re told much of the work was not done according to codes.”

The Hungarian Academy of Sciences last week claimed the dikes were insufficient to withstand an earthquake, and some scientists claim the earthen berms flanking the diverted water are not strong enough to contain the heaviest seasonal flow now filling the channel.

There is a telling climate of panic around the dam, with work crews racing to shore up the earth and concrete sidewalls.

Those living near the redirected river are skeptical of official assurances that there is no need for concern.

“The Danube here is as high as the church steeples in those villages,” warned a local laborer, Csaba Kun, pointing to the surging waters menacingly close to the top of the canal walls. “If the dikes ever gave way, everyone would be flooded immediately.”

The Hungarian Foreign Ministry has appealed to the International Court of Justice in The Hague for intervention. Budapest officials believe the court will order Slovakia to restore the natural route of the Danube, which was diverted in defiance of international agreements on management of shared waterways.

Slovakia is looking to the European Community in hopes of a solution more to the builder’s liking. A special investigative commission appointed by the EC is headed by a Danish hydrologist who has worked closely with Slovak officials on other projects--an association the Hungarians contend should have disqualified him from the role of arbitrator.

Whatever the decision of the mediators, officials in both Budapest and Bratislava appear unprepared for any retreat.

“Slovakia hasn’t violated any agreement; Hungary has,” insisted Pavol Kanis, a leader of the opposition Party of the Democratic Left. “The original treaty envisioned damming of the Danube to make navigational improvements. Reports by the Hungarian side that we are violating the border are simply untrue.”

Gyorgy Tatar, the Hungarian Foreign Ministry official in charge of the Danube affair, speculated that the Slovaks are trying to force Budapest back into the project by constructing an alternative more damaging to the Hungarian environment than the original plan.

“They told us when they were building this that every construction was reversible and that it was all done at their own cost and own risk,” Tatar said. “One has to question why they would embark on a project they will dismantle if they get their way.”

Diverting the Danube

In 1977, Hungary and Czechoslovakia agreed to build a giant complex of dams, canals and power stations on the Danube River between Bratislava and Nagymaros. But controversies have scaled back the project, now focused on Gabcikovo.