Sixteen construction companies and 10 executives were charged with taking part in a widespread conspiracy to allocate jobs and rig bids on riverbank stabilization jobs authorization by the Army Corp of Engineers.

A federal grand jury in New Orleans handed down a 54-count indicatment that included charges of mail fraud and making false statements. A companion civil case by the government was filed in an effort to stop the alleged conspiracy.

The government said the defendants contracted with the Corps of Engineers for construction, repairs and maintenance of riverbanks on many of the nation's principal waterways, including the Mississippi, Missouri, Red and Kaskaskia rivers. The construction work, valued at $53 million in 1976, was in the New Orleans, and Vicksburg, Miss., areas. None of the firms or individuals mentioned is from the Washington area.

The indictment contends that a conspiracy began at least as early as 1964 and has continued until now. The defendants are accused of discussing the job contracts and the submission of bids and exchanging in formation.

The Justice Department said that the result has been higher prices on the government contracts and elimination of competition. The government did not specify how much the alleged overcharges amounted to and the civil complaint did not specify the damages being sought.

Each company could be fined to $1 million if convicted of the antitrust felony charge and each individual could be sentenced to three years in prison and fined $100,000. In addition, the maximum penalty for mail-fraud violation is a $1,000 fine for each corporation and a five-year prison term for each individual.

The false-statement charge also carries a maximum five-year jail term along with a $10,000 fine for individuals and corporations.

The civil complaint also seeks double damages and a forfeiture of $2,000 for each alleged false claim submitted by the companies.