Workshops held today on the development of the last of 10 villages planned for this Howard County new town attracted dozens of Columbians excited about the prospects--and also some neighbors from an adjacent rural village decidedly uneasy about it.

"We have the typical concerns" of a small community facing increased development next door, said John F. Smith of Clarksville, which adjoins the 14,047-acre tract where developers hope to construct mainly multifamily housing for as many as 9,000 people.

Initially, the last village was to contain less development and fewer people, but developers say they changed their plans because of the market and the economy. This change is of less concern to Columbians than to their neighbors.

Columbians view the last village as an opportunity for increased citizen participation in local affairs. They welcome the higher density as a way to lower prices and broaden diversity. Already six citizen subcommittees are at work on issues that include telecommunications, the environment and housing to help make Trotter Road Village reflect "the changed realities of the 1980s."

The realities of the town--which now accounts for nearly half of Howard County's 129,000 people--are different from the visions that underlay its founding in the 1960s. It has just gone through its first school closing. It is neither as diverse economically or racially as hoped. Nor does it provide most of the jobs for its residents, 60 percent of whom commute to work.

But, as Columbia commemorates what some here are calling its "sweet 16 birthday," residents are trying to adapt the old ideals of the town to reality. Today's workshops at a high school were part of that effort.

At the second annual Columbia Forum, 250 participants attended 38 workshops on subjects ranging from the scarcity of affordable housing in Columbia to the new town's potential political clout to whether the unincorporated community should adopt a sister city in Russia or declare itself a "nuclear-free zone."

"Most of the early settlers worked their heads off in the '60s for civil rights, against Vietnam," said Ted Chandler, who has a gray ponytail and has lived in the town since 1970. "Columbia represented the place where good liberals go when they die, so here we are."

In the workshops and at an "idea fair" in the school gym, the echoes of the '60s could be heard. There were anti-nuclear buttons, and some people signed petitions on behalf of locating a "U.S. Academy of Peace" in Columbia.

One group discussed strategy for barring the production, transportation or storage of nuclear weapons in Columbia. A sample resolution, suitable for action by the new town's village boards, was circulated. It asked that Columbia be "taken off the target list of any governments or organizations producing or contemplating the production of nuclear weapons."

Among those speaking at another session was Florence Bain, 87, who moved from Montgomery County to Columbia 16 years ago "to sit back and enjoy my retirement." Instead, she became an activist on behalf of senior citizens, helping establish a center for the elderly. She joined others today in worrying whether the younger generation would sink roots in the new town. "I don't think you have to worry about our generation any more," she said. "The teen-agers are the most neglected group in Columbia. If you want to keep the young people, Columbia should spearhead a commission on youth."

In one workshop people pondered the lack of a cemetery inside Columbia. Suzanne Wallace said she knew of burial grounds in Howard County, but "we thought we couldn't relate to those."

Royce Hanson, former head of the Montgomery County Planning Board and today's keynote speaker, described Columbia as "the one new town in the United States widely regarded as a success. It is growing into adolescence. It is a time to examine some old values, test new ideas, sample opportunities, dream, speculate about the future and face realities."