Green Roof Helping Wisconsin Company Reduce Runoff by 90%

Badger Meter replaces part of existing roof with a green roof, expects to reduce annual runoff by as much as 90% and delay remaining 10% to a time past peak flows.

New green roof at Badger Meter
New green roof at Badger Meter

Wisconsin-based Badger Meter recently decided that a green roof was the best way to replace a 10,000-square-foot area of its existing roof. Many green roof benefits factored into the final decision, the primary being water retention.

During a rainstorm, green rooftops collect and store water that would otherwise run off into the sewer. “We wanted a solution that would be innovative, efficient and all-around better for the company,” says Brian Rogers, Badger Meter facilities manager. “The green roof not only makes sense from an environmental standpoint, it was a sound economic choice.”

The green roof consists of a 3-inch layer of insulating materials, a layer of hard board, a sealing membrane, a leak-detection material and a 4-inch layer of green material. Green material is custom grown for each green roof project off site in modules for about 12 weeks. Because the LiveRoof plants are mature, there is no costly establishment period.

The vegetation is primarily sedum, which is selected, developed and tested specifically for rooftop cultivation. The plants require very little maintenance and are resistant to disease, insects and drought. Several varieties that are green and red in color are arranged in a design that mimics the Badger Meter logo symbol and is visible from above.

The green roof is expected to reduce the annual runoff into the stormwater system (an estimated 249,000 gallons) by as much as 90% and delay the remaining 10% to a time past peak flows. For every 1 inch of rainfall, the green roof collects just under 6,000 gallons of water if it is dry. If it is saturated or frozen, some of the water will run off. By keeping excess water from roofs, parking lots and impervious surfaces out of the sewer system, the company is helping reduce the risk of basement backups and sewer overflows. Green roofs also help prevent rain from becoming polluted stormwater runoff, the biggest remaining threat to our rivers and lakes in the United States.