Jacques Cousteau journeys to Amazonia

For 18 months, Capt. Jacques-Yves Cousteau, with his wife and son and a team of scientists and adventurers explored the Amazon River Basin - a mysterious world of mountains, rain forests, uncivilized natives, and exotic flora and fauna.

Now, their amazing and revealing story is told in a three-part, six-hour series, ''Cousteau/Amazon,'' beginning with a two-hour premiere, Journey to a Thousand Rivers (WTBS, Wednesday, March 28, 8:05-10:05 p.m.; also airing at earlier dates on Superstation WOR and independent stations in some areas; check local listings).

It may prove to be the last authentic record of one of the world's most important ecosystems, before the ''advances'' of civilization complete the damage which has already begun to make ravaging inroads in the delicately balanced environment of Amazonia.

On this 53rd expedition of the Calypso, 26 crew members and several vehicles are photographed in their three-pronged adventure on the world's largest river system which, explained narrator Joseph Campanella, has ten tributaries longer than the Mississippi. Lush jungle and river scenes are portrayed with equally gorgeous cinematic lushness.

One team, lead by Cousteau's son, Jean-Michel, starts its journey at the river's source high in the Andes and travels 1,700 miles downriver, mostly by raft, to meet the Calypso with Papa Jacques in charge. The Calypso had traveled 2,300 miles up from the Atlantic coast. After much travail through flooded jungles and dry river beds, attacks by all sorts of bugs - but with stops to observe the fabulously charming pink dolphins and the not-so-charming piranhas - Jean-Michel's floating Conestoga wagon,'' finally makes contact with the Calypso. What is there left to do but share a good French dinner cooked by Jean-Michel, distribute the mail, and then find a home for the tamed giant otter that has become the expedition mascot?

The second in this $6.5 million series, scheduled to be aired on WTBS April 30, will deal with ''the dehumanization of the native Indians and the devastating effect of the illegal drug trade.'' Third in the series, scheduled to be aired on June 12, will concern itself with Amazonia's ''wild-West gold rush and the effects of industrialization on the jungle.''

Meantime, though, I urge you to find ''Journey to a Thousand Rivers'' somewhere on your TV dial, even if it means calling your local cable system or some independent stations to request it. This may be your last opportunity to see the Amazon in its natural state because, Jacques Cousteau warns, ''the life cycle is being broken; rain patterns are changing. . . .''

''Will the Amazon of the future be proof of our hopeless folly or a testament to our hard-won wisdom?'' asks the good captain in his summation. In ''Journey to a Thousand Rivers'' Jacques Cousteau makes it all too clear to us that if we lose the Amazon we will be losing an important part of ourselves. This voyage of the Calypso was undertaken mainly to publicize that danger to the world at large. As such, it performs a major public service - even as it provides rousing entertainment.