Quick facts:

The green roof measures 10 x 84’. 2-3’ of green roof ballast (pictured as fill rock) surrounds the perimeter and drains into the center.

Funding:

The City of White Bear Lake applied and received VLAWMO’s Capital Improvement Project (CIP) grant.

Reason for project:

White Bear Lake Public works was interested in reducing stormwater runoff, improving building energy efficiency, and creating an aesthetically-pleasing green space on the rooftop. Rooftops are also a common source of contaminants, shedding tar and adhesive particles that wash off with stormwater. The use of a green roof takes away this contaminate at the source. Green roofs and similar projects like rainbarrels are always welcome for watershed improvements, as more of them add up to make a big difference.

Construction:

The green roof features a tray system for stormwater management. Ridges and troughs at the base capture and slowly release stormwater. The design allows for plants to uptake the water but not be drowned in standing water. Plants send water into the air through evapotranspiration. Large rain events may cause overflow into the storm system.

Interlocking tray containers are made from recycled plastic. 

Results:

Reduced stormwater runoff, reduced rooftop contaminants into stormwater, and energy efficiency improvements. 

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