Solving Cities

Portland's largest green roof will be on a Walmart

Portland's largest green roof will be on a Walmart

Posting in Cities

A new Walmart in Portland is building a 40,000 square foot green roof.

When a company builds loads of large, low-rise buildings they have an overabundance of unused rooftop space.

But a new 90,000 square-foot Walmart in North Portland will put its roof to good use. Construction started this week on the Walmart store which will be home to a new 40,600 square foot green roof. Not only will it be the largest green roof in Portland (by 10,000 square feet) but it will also be the largest in the state, DCJ Oregon reports.

Other than the obvious benefit of slowing rainwater runoff, the green roof could be a learning tool for the city:

The difference is significant in regard to measurement of water runoff, according to officials with the Bureau of Environmental Services; it will use the roof to conduct a three-year performance study. Tom Liptan, a landscape architect with the BES and an eco-roof expert, admitted that he was surprised when the company contacted the city about the project. However, he believes it presents a big opportunity.

“If it is indeed this big, it would give us an opportunity to measure stormwater management performance on something we really don’t have,” he said. “We don’t have anything near it.”

The green roof will have three sections with different soil levels to test the most effective green roof practices for building owners and environmental purposes.

From an environmental standpoint it's encouraging to see the retailer adding high-level green building features to their stores. But when you look at the project through an urban design lens it's more of the same from Walmart: a massive single-use store, not connected to transit, with a huge parking lot at the edge of the city. It's not the mixed-use, renovated stores that would do more to add to the retailer's green cred.

The store is expected to open in the fall of 2013.

Walmart’s new store will have Portland’s largest green roof [DJC Oregon]

Photo courtesy of Walmart via DJC Oregon

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Tyler Falk

Contributing Editor

Tyler Falk is a freelance journalist based in Washington, D.C. Previously, he was with Smart Growth America and Grist. He holds a degree from Goshen College. Follow him on Twitter. Disclosure