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We get a lot of press releases trying to woo us to cover the 鈥渂iggest/first/greenest鈥� projects in the Portland-metro area. Most of the time, we give the releases the once-over and decline with a 鈥渃ongratulations, but 鈥︹�� response.

That was almost the fate of the release that arrived yesterday about the green roof on top of Walmart‘s Hayden Meadows store, which was promoted as the largest installation of its kind in the area. But just as we were about to hit the delete button, we received another bit of news about the green roof, a tidbit that added that little something extra that turned our 鈥渘o thanks鈥� into a 鈥測es, please.鈥�

The Walmart roof is big 鈥� 92,000 square feet big. A little less than half of that space 鈥� 40,000 square feet, to be exact 鈥� features green roof. The rest of the area is a bare white membrane surface. The comparison-and-contrast potential is exactly what makes the roof the perfect place for a two-year experiment that will be led by David Sailor, the director of Portland State University’s Green Building Research Lab.

We’ve written about Sailor, who also teaches mechanical engineering at PSU, in the past. He was part of a team that back in 2010 set up an experiment on top of a PSU science building to determine whether eco-roofs could help keep solar panels cool.

For the Walmart roof study, Sailor and PSU students will spend 24 months gathering data collected by a a rooftop weather station and 鈥渟cores of sensors鈥� spread across the green roof. The green roof itself is divided into three sections, each featuring different vegetation and varying soil types and depths.

Sailor and his students won’t be alone as they conduct their research. The city of Portland’s Bureau of Environmental Services will track stormwater runoff from the green roof. The聽Cadmus Group, an environmental consulting firm,聽will study how air conditioner units on the roof perform. The Audubon Society will even get in on the action by counting the numbers and types of birds that visit the green roof.

The research project also will extend beyond Portland to Chicago, where similar studies will be conducted on the green roof of a Walmart store in that city. The resulting data from both study areas, according to Sailor, could have a worldwide reach when it comes to developing strategies to improve how green roofs perform.