The Atchafalaya basin floodway, a tranquil south-central Louisiana home to fur-bearing animals, crawfish, alligators and timber, is caught in a struggle between landowners and government land buyers.

The struggle concerns 443,000 acres of floodway land that Congress wants to buy and put under federal control. Environmental interests support the proposal, which would leave mineral rights with the landowners, but property holders say that such a plan is unnecessary and is nothing more than a "land-grab."

The floodway is vital because it is designed to divert 30 percent of the Mississippi River's flow in the event of a major flood, thereby sparing such down-river centers as Baton Rouge and New Orleans from flooding and damage.

The floodway, which resembles a large, swampy, stream bed, already has some water flowing through it. But this water bears silt, swept down from the upper portions of the Mississippi River Valley, and environmentalists are worried that without special care, sediment will accumulate in the floodway, clogging it like a drain, and damaging trees, fish and wildlife.

Then they say, the floodway eventually would dry up, and property owners would convert their floodway holdings to farmland. However, land owners scoff at this contention, saying that the land is inaccessible, and no good for farming.

These points were argued earlier this year at impassioned hearings throughtout the state. The Agency Management Group, composed of the Army Corps of Engineers, the Fish and Wildlife Service, the environmental Protection Agency and the Louisiana Office of Public Works, is now drawing up a plan for the floodway. After that plan is discussed in still more meetings, the matter will be submitted to Congress.

No one likes the idea of a "federal takeover," said Brian McDaniel, president of the Sierra Club's Baton Rouge chapter, but he said, the purchase plan is the best way to keep the floodway "open and in its natural state."

But landowner Newman Trowbridge of Franklin opposed federal acquisition, predicting it would result in "acquisition and destruction of property rights in that basin. The federal government will become the largest land owner in the state."

About 132,000 acres of the central Louisiana swamp already are under public control; purchase of the 443,000 acres of the floodway would complete governmental ownership of the property, which measures 100 miles by 15 miles and runs from Simmesport to Morgan City. It runs along the Atchafalaya River, which is formed by the Mississippi and Red rivers.

In addition to forests full of such valuable trees as the cypress and tupelo, the swamp is the habitat for a host of fur-bearing animals; about 300 species of birds, including rare egrets and bald eagles, and alligators.

Approximately 23 million pounds of crawfish are caught there annually, and the floodway's value in terms of fish wildlife and related recreational resources is $97 million per year, according to a survey taken by the Army Corps of Engineers and the Louisiana Department of Wildlife and Fisheries.

Purchase of the 443,000 floodway acres is only one of 10 plans that the Agency Management Group have proposed, but it is the one that has attracted the most attention. Other possible plans include channel dredging, raising and extending levees, changing the amount of Mississippi River water flowing into the basin and building a new levee system.