Roy T. Dodge, a quiet, courtly man who has supervised the building of the Washington Metro from the first $12 million contract in 1969 to the $3.3 billion system that is now completed or under construction, announced his retirement yesterday.

Dodge, 60, a retired brigadier general in the Army Corps of Engineers, told Metro General Manager Theodore C. Lutz that he did so with regret, but that "after 10 1/2 demanding years I feel it is time to attend to personal and family plans."

He has no plans to work and will stay in the Washington area, he told reporters. "Three years ago I bought a grandfather clock kit. It's still in the cartons," he said.He retirement will be effective May 1.

When he leaves, almost one-fourth of Metro's planned 100-mile system will be in operation and construction will be under way to complete a total of 60 miles.

Dodge and the other Corps of Engineers cadre around him have been accused of building a Cadillac when the region could get by nicely with a Chevrole. Metro's total construction bill, originally estimated at about $2.5 billion for the 100 miles, has been pushed to more than $5 billion, largely because of inflation and political delays.

At the same time, Dodge has forged a remarkable reputation for integrity, the first word used by both friends and critics of Metro to describe him. There have been no scandals in the construction of the nation's largest public works project.

Roy Dodge is the only man with enough internal clout in Metro's contractor selection process to direct dollars to a specific firm.

He conceded that in an interview last October. "I could direct that (a selection board) go one way and favor a specific contrator," he said. "But it doesn't work that way.

"There is an invitation for political influence here," he said. "Early on (in Metro construction) we had a lot of letters from congressmen. But they died down over the years. I think construction firms realized that that had little effect.

"We have made a concerted effort to spread the work around and have used up to 40 firms."

Dodge was brought to Metro by his former military superior, Jackson Graham, another retired general. Over the years, Dodge was one of the few people who were considered close to Graham, the general manager who actually got the politics and the money together to put Metro in the ground.

Graham retired just before Metro's first subway line opened in March 1976. He and Dodge remained close. Graham called Dodge after a construction accident in the Washington Channel resulted in a flood that closed the Blue Line in late August.

Dodge said yesterday that he called Graham on Wednesday night to tell him his retirement would be announced at yesterday's Metro Board meeting. "Jack though it was great and asked me to come out and see him," Dodge said. Graham has retired to California.

Dodge is the last of Graham's original key lieutenants still with Metro. Dodge's two top assistants also are expected to retire within the next one to two years. This means that Lutz will have to rebuild the top management of his construction team at the same time Metro's financial and political base is undergoing intense local and federal scrutiny.

Dodge has supervised some impressive engineering projects in his 29 years with the Corps and 10 years with Metro. He received national attention in 1966 when, as chief of the Corps of Engineers' north central division, he announced the plan to turn off Niagara Falls so repairs could be made.

He resented the Corps' reputation with civilians for bulding overdesigned, expansive projects and said so in October. "When you're in heavy construction, underground, yet get into a lot of trouble," Dodge said. "The Corps hasn't designed these projects: they were all done by civilian design firms."