WATERVILLE — The Planning Board on Monday approved final plans for a $200 million, 350,000-square-foot athletic complex at Colby College that college officials say will have the first Olympic-sized swimming pool in the state.

The board voted 7-0 to approve the plans with conditions, including that the board receive a letter of approval from the city’s fire chief, David LaFountain, as well as a traffic movement permit from the state Department of Transportation. The complex would be built on Campus Drive, diagonally across the street from Johnson Pond, and is expected to be the largest in the New England Small College Athletic Conference, which includes Colby, Bates, Bowdoin, Middlebury, Hamilton, Trinity, Williams, Amherst and Connecticut colleges, as well as Wesleyan and Tufts universities.

The building is expected to be ready for occupancy in 2020, after which the current Alfond Athletic Center would be demolished to create green space that will be completed in 2021, according to Mina Amundsen, Colby’s assistant vice president for facilities and campus planning.

“We propose to start in summer, so we hope to be in the ground in August,” Amundsen told the board.

She said the design is environmentally sensitive and wetlands are being kept intact as part of the project.

The building will have a landscaped courtyard that is open to the sky.

Stephen Mohr of Mohr & Seredin Landscape Architects Inc., of Portland, who was present Monday, said at a recent meeting that the building will be on 30 acres, 27.5 of which already are developed, so only 2.6 acres will change as a result of the new development.

The building will have an indoor competition center with a 200-meter track and a multi-level, 13,500-square-foot fitness center that will be available for use by the community, region and state. It will be among the best Division III facilities in the country, according to Colby officials. A gymnasium, 50-meter swimming pool, squash and aquatic centers, hockey arena, studios, training rooms and coaching suites are part of the plan. The center will serve as a resource for the entire campus, as well as for athletes from Waterville, the state and New England, Colby officials have said. The aquatic center is expected to become a destination in northern New England for swimming groups from across the state.

The project represents the largest single one in the college’s history and is expected to be an economic boon to the city, bringing in more than $1 million in revenue a year to the area from people staying in hotels and eating and spending money on other activities, according to Colby President David A. Greene.

Excavation started last year to move Colby competition fields to create space for the new athletic complex. Those three new competition and recreational fields include a practice field, a competition soccer field and Bill Alfond Field, which will continue to be used for competition field hockey and lacrosse. The new fields are behind the current athletic center and will be playable in the fall.

Last year, Colby also built and opened a lighted, turf baseball-softball complex off Mayflower Hill Drive east of the current athletic center that will continue to be available for the community and local school teams.

In other matters Monday, the board reviewed an informal preapplication by Trafton Realty LLC for a 120,000-square-foot commercial building to be built on Trafton Road.

Christi Holmes of Gorrill Palmer Consulting Engineers of Gray, said the building would be constructed about a mile west of the Interstate 95 interchange that is being built off Trafton Road. The site on which the building will be constructed is about 75 acres, Holmes said.

She said the owner anticipates having six tenants in the building that may use the space for warehousing, storage and possibly light manufacturing.

“The building is set back 150 feet from that southern abutter,” she said.

The board was not required to vote on the plan Monday.

Also, Webb Road Storage LLC presented an informal preapplication plan for a 9,360-square-foot storage unit complex to be built at the intersection of Webb and West River roads. It is being proposed by Tim Millett.

George Courbron of SurveyWorks, Inc., of Greene, represented the project Monday. He said plans call for three storage buildings, at 140-by-24 feet, 130-by-24 and 120-by 24. The buildings would have 30, 28 and 26 units, according to Courbron. He said he would be back for preliminary and final review June 19. Board members asked what he planned to have for screening at the site. Courbron asked City Planner Ann Beverage if it would be appropriate to consult the abutting landowner what he would prefer for screening. Beverage said that would be a good idea. No vote was required Monday.

Amy Calder — 861-9247

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Twitter: @AmyCalder17