COLUMN ONE : A Crusade for Nature in Japan : There is fear that the nation’s ‘last natural river’ could be destroyed. In a country where the ecosystem has been so methodically conquered, some now mourn its loss.

Concrete dikes the height of small castle walls encircle this town, actually a man-made island where the ground lies as much as 9 feet below sea level and is sinking, inexorably, into Ise Bay.

The community has had a precarious history of flooding and misery in its more than two centuries of existence. Mayor Senshichi Ito still cringes at the memory of his wife and two sons being swept away by floodwaters during the catastrophic Ise Bay typhoon of 1959, one son surviving, miraculously, by grabbing a neighbor’s roof.

Nagashima, west of Nagoya, might have been just another example of the myriad of human settlements throughout these overcrowded islands where nature has been extremely unkind. Year after year, Japanese battle and lose their lives to a harsh environment of volcanoes, mudslides, earthquakes, not to mention floods.

But a new twist on the man-versus-environment epic has come to Nagashima, one in which some Japanese are brooding over the loss of the natural ecosystem they so methodically conquered.

It was here that a 20-year-old pork barrel project was revived three years ago and sparked a fury among Japanese environmentalists, who claim the $1.1-billion dredging and estuary barrier project under way outside Nagashima’s walls will destroy Japan’s “last natural river”--the Nagara-gawa, literally the “long and good river.”

Activists contend the Nagara is the only major river in Japan that has not had its currents spoiled by a dam. They believe the estuary barrier is unnecessary because the logic of its original plan--harvesting water for industrial use--is obsolete. And they say it will ruin upstream fishing grounds and possibly increase the danger of flooding at the headwaters.

The alarm they are sounding is prompting an extraordinary debate over Japan’s environmental values. Sympathy for the Nagara protest has become a kind of litmus test for environmental convictions among members of Parliament, who argue about it across party lines. It is perhaps Japan’s first environmental crusade for the everyman, with young urban dwellers getting involved--partly for fun.

Thousands of canoes, kayaks and sailboats have turned out each spring for the past three years to form a festive regatta of protesters on the Nagara, demonstrating a remarkable new media savvy for the traditionally sanctimonious, inward-looking Japanese environmental movement.

The Japanese have been notoriously apathetic about environmental issues that don’t have an immediate effect on their own nests. Past struggles against industrial pollution, such as the Minamata mercury poisoning case, typically were waged for years by victims alone before national and international environmental crusaders got involved. The trend now, activists say, is to embrace the principles of ecology up front and intervene early in disputes.

But behind the environmental boom, and the symbolism of the “last natural river,” is a melancholy sense of loss.

“There might be a small river somewhere in Japan, maybe in Hokkaido, that is completely natural, but I can’t name it,” said Tatsuo Nakai of the Nature Conservation Society of Japan. “Japanese are waking up to all the ecological destruction that happened over the past 30 or 40 years of intense economic growth, and they’re distraught because they don’t know how to reverse the damage. People are realizing that when their lives slow down and they feel like taking a walk in the woods, the woods aren’t there anymore.”

Sentimental hogwash, says Nagashima Mayor Ito. He and his town council, along with practically every local official in the vicinity and the governors of the three prefectures (states) involved, strongly support the dam project, scheduled for completion in 1995.

Ito says he doesn’t understand how people can be so misinformed about the Nagara, one of three rivers feeding the delta from which Nagashima was carved in a 1750s samurai public works project.

“If we wanted to return the Nagara to its natural state, we’d have to go back more than 100 years and rip out all the retaining walls and embankments,” said Ito, 67. “This would be seawater where we’re sitting.”

Indeed, the Nagara is no pristine river by non-Japanese standards. The scenery of the headwaters around Nagashima is a depressing, monotonous, industrial gray, belying the area’s curious designation as a national park. In fact, over the past 80 years, the banks of almost the entire length of the 103-mile “long and good river” have been paved with stone or concrete retaining walls to limit flooding, officials at the Ministry of Construction say.

Yet the waters remain clean and abundant with ayu , a small, bony, sweet fish that migrates upstream each summer and is prized for its delicate flavor. It is the Nagara River ayu that get swallowed and disgorged in the ceremonial cormorant fishing that is a vital tourist attraction for the city of Gifu.

(Cormorant fishing, it should be noted, is a textbook illustration of Japan’s (and Asia’s) traditionally manipulative relationship with nature: Hungry birds are trained to dive for fish with leashes tightened around their necks, preventing them from swallowing their catch.)

The ayu population is not in danger, authorities claim, because fish ladders will be built into the estuary barrier and an artificial breeding program will supply plentiful stocks.

But the Construction Ministry’s own data suggests otherwise. When a similar estuary barrier was built on the neighboring Kiso River, the ayu catch was nearly halved--from 152,000 pounds when construction began in 1979, to 77,000 pounds in 1988, the latest year for which figures are available.

“If these fish ladders worked so well, then why are they paying billions of yen to compensate fishery unions for their losses?” asked Yasuji Yasufuku, 75, an avid amateur fisherman in Gujo Hachiman, a picturesque mountain village on the upper reaches of the Nagara.

“Already we’ve lost much of our ayu run,” lamented Yasufuku, who makes his living carving folk Buddhist statues. “I started fishing with my father when I was 9, and the river was teeming with fish. All you needed was a bamboo pole to stick in the water and you could catch 30 ayu a day. It’s not like that now.”

The government has paid undisclosed amounts of money, estimated to be in the tens of millions of dollars, since the plan was first approved in 1968, buying off the rights of commercial and amateur fishing associations along the river.

The green light to begin construction three years ago followed a sudden breakthrough in negotiations with shijimi clam fishermen in Ise Bay, whose catch would be devastated by the change in the way fresh water mixes with salt water below the estuary barrier.

Satsuki masu, a rare species of trout, are another cause celebre for opponents of the dam, who say the fish is found only in the Nagara River. The Construction Ministry disputes that, saying the fish is simply known by another name in nearby rivers.

“It’s a question of what is natural anymore,” said Masanori Shinagawa, a local Construction Ministry official overseeing the construction. “The Nagara River is almost totally man-made at this point. The river has adapted to something like a natural ecosystem, but you can’t say it’s anything special or near a natural state.”

Local residents have largely remained silent on the dam, reflecting a cultural tendency to eschew controversial issues--or perhaps they are displaying a collective fear of floods, from which the project is supposed to protect them.

Megumi Omori, a homemaker turned firebrand protester, is the exception in Nagashima.

“A lot of people around here are afraid to speak out because of bad memories of the flooding,” Omori said. “I’m a newcomer and I don’t really know the terror of the Ise Bay typhoon, but my neighbors tell me I’ve got a lot of courage to move to such a dangerous place.”

She and her husband bought a plot here 15 years ago from developers selling off swampy farmland to cater to a booming population in the Nagoya area. Omori was uninterested in the dam construction until one day, in the summer of 1989, she was riding her small motorbike across the Nagara and saw that workers had torn up a section of marsh where she enjoyed watching birds.

“That wonderful marsh was suddenly in ruins, and it had this horrible stench,” she said. “All the living things in the marsh had been dredged up and they were rotting. The nests were gone, and the birds were flying around in confusion.”

Omori became a zealot and started a band of Nagashima residents to fight the dam. So far she has recruited five people, all newcomers.

Japanese from distant places have had better luck organizing. Spearheading the anti-dam movement has been a charismatic sports fishing journalist from Osaka, Reiko Amano. She enlisted such celebrities as the late Ken Kaiko, a prominent man of letters and fishing enthusiast, and orchestrated the colorful flotillas of protesting boats to entice television news cameras.

Her group also has lobbied fairly successfully in the murky political world, where power and wealth are traditionally gained by promoting public works projects, not trying to stop them. Yet the activists persuaded several members of Parliament to call for a halt in construction pending a new environmental impact assessment.

So far, that remains an elusive goal. Kazuo Aichi, the present Environmental Agency chief whose predecessor had spoken out against the Nagara River dam, has declared Japan’s environmental activists “ideologically strange.”

“I don’t know why there’s such a fuss over the Nagara River. It seems to have become a symbol of something,” said Aichi, who has a reputation as an “internationalist” in Japan’s stodgy ruling party.

The Nagara River symbolizes many things, not the least of which is the reluctance of Japan’s powerful bureaucracy to compromise at any cost. Under Japanese law, the government agency sponsoring a public works project is charged with conducting its own environmental assessments.

In the case of the Nagara River, the Construction Ministry and its semipublic arm, the Water Resources Public Corp., are sitting on reams of data, including about 6,000 pages from a study conducted by 90 scholars and experts between 1963-67. The ministry refuses to release the data for independent analysis. Japan has no statutes to force the central government to release information to the press or public.

“That’s the system of environmental assessment in Japan; that’s the process,” said Takashi Toyoda, a ranking official with the Construction Ministry in Tokyo. “If you’re talking about problems with the assessment procedure, it’s no longer the Nagara River estuary gate that’s in question. It’s the Japanese government’s way of doing things.”

Amano, the leader of Nagara protest, sees the popularity of the Nagara River movement as proof that people are ready to challenge those time-honored habits of governance.

“The Nagara is not just Japan’s last natural river,” Amano said. “This is a case where the Japanese people are questioning the fundamental policy of the Construction Ministry to sell off our mountains and rivers.”

The Nagara River, whether it is seriously threatened or already beyond redemption, is a symbol of awakening. But it may become a tragic symbol of despair, because, for Japan’s natural environment, the awakening may be far, far too late.

Yasufuku, the Buddhist sculptor from Gujo Hachiman, recalled an eye-opening fishing trip on the Klamath River during a recent visit to Northern California: “I was astonished--there’s not a speck of garbage on the Klamath River. It’s truly unspoiled. I asked one of the local people why. He was an Indian, and he said the river is sacred, and so it must not be spoiled. I thought, ‘What’s happened to us Japanese? Why have we stopped regarding our rivers as sacred?’ ”