Government witnesses, offering a glimpse into the world of multimillion-dollar drug operations, testified yesterday that an Alexandria man smuggled drugs valued at $36 million into the United States by sea during an eight-year period, sometimes flying his boat crews to pickup sites on the supersonic Concorde.

These were some of the details that emerged yesterday at the trial of Leon Durwood Harvey in U.S. District Court in Alexandria. Harvey, 37, is charged with running a criminal enterprise in Northern Virginia that imported marijuana and hashish into the United States from Jamaica, the Bahamas, Lebanon and Thailand.

Harvey also has been charged with tax evasion, customs violations, racketeering and obstruction of justice.

Yesterday's testimony by witnesses identified as former associates of Harvey, most of them serving prison sentences for drug-related charges, is critical to the government's attempt to prove Harvey ran a continuing criminal enterprise. That charge carries a mandatory 10-year minimum sentence with no parole during that period.

Harvey's attorney, John Zwerling, has argued that Harvey was participating in "joint ventures" with others and that he was not in charge of the drug smuggling.

Peter James Bryant, who is serving a seven-year sentence on drug importation charges, testified yesterday that he and Harvey cooperated on 11 drug runs between 1977 and 1984 that brought $36 million worth of marijuana and hashish into the United States.

Bryant said that Harvey, whom he said he has known since 1968, once told him he had organized 52 drug smuggling runs.

Describing one trip to Beirut during heavy fighting in the fall of 1982, Bryant said Harvey sent the 53-foot sloop Estrelita to pick up 9,000 pounds of Lebanese hashish. "It was the only boat in the harbor," Bryant testified. The contraband was delivered to the United States in January 1983, he said.

Bryant testified that while his role was to procure and outfit boats for the drug runs -- services for which he earned fees ranging from $100,000 to $500,000 -- Harvey was the overseer. "Mr. Harvey controlled the ball game . . . . Mr. Harvey was always in control," he said.

Robert Reckmeyer, who with his brother Christopher pleaded guilty last year to running a multimillion-dollar drug operation, also testified yesterday. He told the court that he had sold two machine guns to Harvey and Harvey had advised him on how to transport large sums of money out of the United States to conceal it in banks in the Bahamas.

Under cross-examination by Zwerling, Bryant and two other witnesses -- Barry Toombs and Phillip Marinovich -- testified that Harvey was a heavy cocaine user. But when asked by prosecutors if Harvey was coherent when he was making drug deals, the witnesses testified that he was.

Harvey, whose case is being heard by U.S. District Judge Albert V. Bryant, faces a maximum penalty of life imprisonment if convicted.