Douglas County’s top officials faced a crowded house as they decided to approve the groundwork for a massive residential development.

The Board of Douglas County Commissioners unanimously approved a rezoning application and water appeal May 11 for the 3,400-acre Sterling Ranch development proposed to be built in Chatfield Basin. The community will be built out over several decades and contain a variety of housing, including condos, acreage properties and patio homes.

If the project gets final approval, its developers expect as many as 31,000 people to reside in Sterling Ranch one day. Commercial shopping areas, an elementary school and open space corridors are also part of the plans.

Those who oppose Sterling Ranch have expressed concerns about high traffic volumes, high home densities and the availability of water to sustain the development.

Several organizations, including the South Metro Denver and Highlands Ranch chambers of commerce, have come out in support of Sterling Ranch.

Steve Dyer, president of the Highlands Ranch Chamber, says the preliminary approval by the county commissioners will result in positive growth and a larger tax base for Douglas County. The chamber will either partner with a business organization in Sterling Ranch or start its own branch to help the commercial components thrive.

“The bottom line for us is to help business in any way we can, and if that means expanding our services out there, that’s what we’ll do,” he said.

The vote by the commissioners came after four evenings of public testimony and months of hearings. Nearly 200 residents spoke in support of the project or wanted answers to tough questions about potential negative impacts.

The Sterling Ranch website says officials expect to begin building infrastructure in 2012. Construction of the first village is planned for 2013.