The 82-year-old swimming pool that has become one of the last visible reminders that the Hawai'i State Art Museum building was once a popular YMCA will be filled in and converted into a seating area for museumgoers and the public.

The $1.5 million project is mostly aimed at addressing the liability that the swimming pool — unused since at least the 1990s — has become. But the work is also part of a bigger push to increase space for the Downtown art museum.

"It is a beautiful spot," Peter Rosegg, O'ahu commissioner for the State Foundation on Culture and the Arts, said of the shady courtyard behind the museum where the swimming pool now takes center stage. "But it is a huge waste of space."

Because the pool isn't open, the courtyard is blocked off to the public.

Visitors to the art museum can see the pool, though, when they walk onto a lānai overlooking the courtyard or sit at the museum's cafe, Downtown@HiSAM.

Historic preservationists are backing the plan to fill in the pool — largely because the state has pledged to retain the historic feel of the 7,700-square-foot courtyard area and preserve the original tiled deck that surrounds the pool.

The project also includes disability access improvements.

Money for the work comes from the state's Works of Art special fund.

Under the plan, the state will partially fill in the pool and create a sunken seating area and garden in its place. The areas surrounding the pool will feature planters, seating and "opportunities for placement of sculptures," Rosegg said.

Work is scheduled to start in August, and wrap up in February 2011.

Rosegg said the pool is an "attractive nuisance," and that the courtyard revitalization will "remedy potentially dangerous conditions surrounding the pool area and provide a usable space ... while respecting the history" of the building.

He said he knows of no instance of someone trying to get into the pool.

But he added the swimming pool is also sucking up maintenance costs, even though it's unused. The state spends $10,000 a year to keep the pool clean.

The pool dates back to 1928, when the building was a widely used YMCA. Countless service members and schoolchildren used the facility at its peak, and at one time school competitions were held in the pool, which is 75 feet by 30 feet.

In 1987, the Hemmeter Corp. bought the property for about $11 million and completed some $29 million in building renovations. The building changed hands again in 1990, when the BIGI Corp. of Japan bought it for $80 million.

The state started leasing the building in 1990 for offices.

It bought the building in 2000, for $22.5 million.

Two years later, the Hawai'i State Art Museum opened at the site.

Ron Yamakawa, executive director of the Hawai'i State Foundation on Culture and the Arts, said the courtyard work comes as the art museum is in desperate need for more space, especially for its popular programs for schoolchildren.

He said the new courtyard could be used as a teaching or gathering place.

Rosegg added that there's no doubt some will be sad to see the pool go — especially those who remember swimming in it in their childhood. But he added that the only other alternatives were doing nothing or revamping the pool for use.

He said refurbishing the pool to be used would have been impractical and expensive, since it would have required the pool be brought up to code and the state would have had to hire lifeguards. The state didn't pin a dollar estimate to a refurbishment project because it was considered too pricey.

Rosegg added, "The pool, while a significant part of the Armed Forces YMCA programming, is not appropriate for the current use" of the building, which houses the art museum in addition to other state offices, a popular cafe and a gift shop.

He also said, in response to questions about whether the state should be revitalizing the courtyard in the midst of a fiscal crisis, that the work will create jobs, do away with pool maintenance costs and improve the museum experience.