Jan. 29, 2015 -- The Metropolitan Water Reclamation District of Greater Chicago (MWRD) announced that it has officially completed the construction of a green roof at its Racine Avenue Pumping Station (RAPS).
RAPS is a building that houses main sewage pumps, which transport wastewater to the Stickney Water Reclamation Plant. The coarse screen building extension houses a conveyor system that removes trash from wastewater, which helps prevent damaging water treatment pumps. The structure's total building roof area is 33,000 square feet, with approximately 4,500 square feet being structurally rated to handle the additional vegetative roof loading.
Originally constructed in 1939, the most recent roof replacement was performed in 1996 with a 10-year warranty. The 19-year-old tar roof showed its age; numerous leaks and worn-out repairs required replacement. However, instead of replacing the roof with heavy, impermeable tar, the new roof is a combination of asphalt and planting.
Because of their ability to withstand harsh weather conditions, a variety of native, low-maintenance Sedum plants were installed. Irrigation is initially needed to establish the plantings as well as during drought periods, and routine weed removal will also help the roof maintain its appearance.
"We all know that Chicago weather can be harsh, and we face extreme temperature swings and moisture levels," said MWRD President Mariyana T. Spyropoulos. "This new vegetative roof is definitely an improvement and will greatly benefit the agency and the environment. We expect it to slow stormwater runoff and absorb heat. It also has an insulating effect for the building, which will result in lower electrical costs for operating the building."
The MWRD will also continue to monitor the success of the plantings and maintenance costs and use this information as it continues to seek other opportunities for green/vegetative roofs. Green infrastructure is an important tool in the effort to reduce flooding. While rain gardens, rain barrels and permeable pavement are more common forms that can be found around the region, another equally useful method of capturing stormwater can be found in a green roof.
See also:
"MWRD to offer investors 'Green Bonds' for environmentally-friendly projects"
"MWRD, Denmark sign MOU to share knowledge, expertise about water industry"
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