Green rooftops sound great. I expect structural carrying capacity limitations will be the principle limiting factor for such projects, since the buildings were not originally designed to support the extra weight associated with gardening... maybe a relatively 'thin-film' hydroponic approach would minimize the added weight?
Michael Hohmann -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Corrie Zoll Sent: Monday, February 04, 2002 9:04 AM To: [EMAIL PROTECTED] Subject: [Mpls] CSO's & Rooftop Gardens I was excited to see this morning's Strib article about Minneapolis's Combined Sewer Overflow (CSO) problem (http://www.startribune.com/stories/462/1405414.html) It's not the raw sewage pouring into the river that's exciting, but the idea that, this time, the problem might get fixed. snip ...Evidently 2001 saw 6-8 CSO events during which the city's combined sewer system overflowed, dumping raw sewage into the river. snip ...As the Strib article notes, one of the big problem is rooftop drains. These drains often connect to a building's plumbing system and drain along with toilets and sinks into the city's sanitary sewer system. Correcting the problem would involve major re-plumbing of large downtown buildings. What the Strib article did not mention was that these buildings may not be adjacent to existing storm sewer lines. And even if they are, the existing storm sewer lines may not be able to handle the increased volume that would come with storm water from rooftop drains. New sewer lines will be needed and existing sewer lines will need replacement. That's what makes correcting the problem such a massive infrastructure project. I'd like the city to investigate whether rooftop gardens are a cost effective method for retaining rooftop stormwater. Green rooftops can hold 70 - 100% of the stormwater that falls on them. snip ...Chicago's city hall has a new 20,000 square foot rooftop garden. Studies will compare this rooftop with the asphalt rooftop of an adjacent building to quantify the costs and benefits. Green rooftops might entirely solve the CSO problem in Minneapolis... snip Corrie Zoll Phillips Neighborhood _______________________________________ Minneapolis Issues Forum - A Civil City Civic Discussion - Mn E-Democracy Post messages to: [EMAIL PROTECTED] Subscribe, Unsubscribe, Digest option, and more: http://e-democracy.org/mpls
