West Lebanon — The developer of the proposed River Park project along the Connecticut River is asking city officials to amend his plans for the roughly 840,000-square-foot development to better prioritize its housing component.

David Clem is requesting permission to move up construction of an 80-unit apartment building slated for a 2-acre lot near the end of Crafts Avenue. The roughly 125,000-square-foot building was intended to be the last of nine structures built at the development between Route 10 and the river, but Clem now says the plan should change to help alleviate the region’s housing needs.

Experts say that about 5,000 units of workforce housing are needed in the Upper Valley, and by building soon, Clem hopes to tap into that market.

At the same time, he also predicts an immediate need for biomedical and life science space, two industries that River Park was designed to house.

“Based upon the above, we are prepared to accelerate the development of certain life science buildings and the residential component of River Park,” Clem said in an Oct. 9 letter to the Lebanon Planning Board, which will review the changes next month.

“We believe that this is a watershed moment in the development of River Park and we look forward to working with the city of Lebanon to move this process forward,” he wrote.

Clem — who has helped develop life science buildings in Houston; Cambridge, Mass.; and Boston’s Longwood Medical Area — declined to comment on his plans when contacted earlier this week.

Crews are working to complete sewer line under Crafts Avenue that someday will connect River Park to the city’s system. In his letter, Clem predicts that work will be complete next month, when construction can start on nine new homes and a cul-de-sac at the end of the roadway.

Clem also reported that he is in talks with a “major international high tech company” to lease the majority of 100 River Park, the first mixed-use building planned for the development. Plans show the building with retail space on the ground floor with 60,000 square feet of offices above.

“Based upon the financial strength of the tenant and the size of the lease, we are prepared to begin infrastructure and foundation work for this project upon execution of the lease in late fall,” Clem wrote.

Since River Park was approved by Lebanon officials in 2011, the Upper Valley has invested heavily in its medical and scientific industries, Clem said in his letter.

The Dartmouth Regional Technology Center, an independent, nonprofit business incubator, is in the Centerra business park in Lebanon; nearby Dartmouth-Hitchcock Medical Center continues to grow its efforts; and the Thayer School of Engineering is one of several New Hampshire schools recently awarded $20 million for life science research, he noted.

Factored together, those developments are promising enough to begin planning the construction of another River Park building, according to Clem.

In his letter, he also proposes moving up the construction of retail and office space in the West Lebanon development that could total about 90,000 square feet.

The facility, called Building 5, would be used “for similar purposes to 100 River Park” on a 1.2-acre lot abutting Route 10, Clem wrote.

The structure was scheduled to be developed third, after both 100 River Park and a lab building planned for a parcel at the rear of the development, closer to the Connecticut River.

The retail and office space still would be third in line for construction, Clem’s letter said, but housing would take priority.

“In this environment, we are increasingly confident that the vision of River Park as a vibrant center of life science will soon become a reality,” Clem wrote.

To complete both buildings, Clem would be required to use temporary, off site parking on land that will be later used for a parking garage.

“The parking will be well graded, drained, lighted and otherwise constructed to meet the safety and other concerns of its users,” he wrote. “By its very nature, as temporary parking, it is not intended to meet all of the standards for permanent accessory parking.”

Work also will begin on River Park Drive, the road that will wind through the development, and crews will be extending water and sewer from Crafts Avenue to serve the three buildings.

The Planning Board is expected to discuss Clem’s requests during its regular meeting at 6:30 p.m. on Nov. 13 in City Hall.

Tim Camerato can be reached at tcamerato@vnews.com or 603-727-3223.

Correction

The Dar tmouth Regional Technology Center is an independent, nonprofit business incubator whose board members include representatives from Dartmouth College, Grafton Regional Development Corporation and North Country Council. An earlier version of this story incorrectly described the center’s governance status.