"All my life," Bernard (Ben) Brenman says, "I've wanted to build a park."

Brenman's hand sweeps across the view from his apartment window in Alexandria's West End. Below him a small stream called Holmes Run meanders southward through a narrow park. In Brenman's mind the park is bigger, better kept, set with flowers and enlarged to include a library -- a park like the one on the map at his feet.

After three years of work, the Holmes Run Committee, with Brenman as one of its principal spokesmen, has persuaded the Alexandria City Council to adopt its plan for more open space around Holmes Run. Last month the city voted to go forward with land acquisitions and other improvements that will bring the park close to what West End residents have wanted.

Brenman was "doing the city's planning for us," said Mayor Charles E. Beatley Jr. Brenman was the only person to recognize "the potential of tying together all those unconnected spaces along Holmes Run."

If you are an Alexandrian with a cause, the 64-year-old Brenman is the man to have on your side. Alexandria city officials say that for the last several years he has been one of its most successful and best-known citizen activists.

He can be counted on to make the meetings, do his homework and know the people he is dealing with. Alexandria Vice Mayor Patricia Ticer calls Brenman "probably the epitome of citizen activism." Outgoing City Manager Douglas Harman calls Brenman's work "a model of what citizen involvement can do."

Brenman combines hamming it up in public meetings with a lot of behind-the-scenes hard work. He is also forceful. Dayton Cook, head of the city's Department of Transportation and Environmental Sercices, said that "nobody ever has to guess where Brenman stands on an issue." Cook believes, however, that Brenman's style sometimes can trip him up, and says that Brenman has been known to try to go too far on too few facts.

For nine of its 10 years, Brenman has chaired the Alexandria Archeological Commission, a group of residents appointed by the City Council and charged with promoting archeology. In a city fascinated with digging up its past and willing to spend the money to do so, such a group has considerable influence. In 1984 for instance, the city spent $117,000, five times as much as New York City and 15 times as much as Boston, on archeology.

With Brenman greasing the wheels, the commission recently has won three important battles for archeology in Alexandria. It has secured a place for the city's archeology program at the Torpedo Factory Arts Center and gotten an archeological survey done at Jones Point Park, the largest tract of parkland on the waterfront. Perhaps its biggest accomplishment was persuading Savage Fogerty, the developers of Trans Potomac Canal Center, a private office complex now under construction on the north end of the waterfront, to restore a lock of the Alexandria Canal and provide space for a city museum there. Brenman also fought for open spaces at the Canal Center, which is being built on one of the two open plots of urban land remaining on the Potomac.

The apartment Brenman shares with Estelle, his wife of 40 years, is filled with artifacts collected on travels around the world: from a small milk bottle from the old Alexandria Dairy to the base of a Greek column the couple used as a door jamb while living in Turkey.

Both Brenmans are first-generation Americans: he the son of a Russian father and English mother, she born to Austrian parents. Part of the motivation for the work Brenman does is to "return something to this country."

He and Estelle met as children in Philadelphia. They now have two children of their own: Marc, who lives in San Francisco, and Barbara Newman, a disability benefits specialist who lives in Fairfax County.

Brenman enlisted in the Army in 1942, just six months away from a degree in agronomy at Pennsylvania State College. "I had to go win a war," he said.

His 30-year Army career took him from private to colonel, with combat service in World War II and Korea. He later earned degrees in biochemistry while serving in Turkey (1953-56 and 1964-66), a bachelor's degree at the University of Ankara and a master's at the University of Ismir.

In January 1971, Brenman, retiring as head of the Army Combat Support Group, faced two choices: he could use contacts developed while in the Army and go into industry, or he could do "what I wanted to do." He chose the latter.

"Here I am," Brenman said, "building parks, chairman of the Archeological Commission, working with children in scouting . . . I'm as happy as can be."