Bott Swensen tech appdx A by lanyuehua


									Appendix A
                 Decentralized CSO Analysis: Framework Matrix for Policy Options and Criteria

Primary Criteria     Sub-Criteria           Green Roofs               Landscape swales               Rain Barrels               Rain Cisterns             Porous Pavement

                                       2-year storm: 11.76%          2-year storm: 5.50%         2-year storm: 7.04%        2-year storm: 29.33%        2-year storm: 13.50%
                      Peak Flow
  In-system                            25-year storm: 5.88%         25-year storm: 1.75%        25-year storm: 1.60%        25-year storm: 6.67%         25-year storm: 3.0%
                    Average Annual
                                               1.47%                        21.75%                      1.44%                       6.00%                      14.25%
                   Volume Reduction

                                        Ideal roof has 5-20*             Minimum size
                                               slope2                 requirements: 1% of
                                                                       impervious area +                                                                   Suitable for new
                                        Load reserves 15lbs/       between 0.5% - 2% grade       Implementation easy
                                                                                                                                                       construction and retrofit
                                          sq ft > snow load             + 3:1 side slope3                                  Majority of Fremont pilot   projects; good for almost
                                       requirements needed 2                                      Survey shows 2/3
                      Widespread                                                                                           focus group participants           any setting6
                                                                    Landowners may lose a          public support4
                    Implementation                                                                                           reacted positively to
                                          Non-uniform roof             portion of yard                                                      4
                                                                                                                                   cisterns               Installation can be
                                          designs present                                        Successful voluntary
                                                                                                                                                       disruptive to landowner
                                           implementation          Yards are various shapes       program in place5                                    which may limit appeal
                                             challenges             and sizes; may present
                                                                    design and installation
                                      Installation is disruptive        complications

                                         City of Seattle has
                                                                      Drainage Swale not
                                      considered adding LEED
                                                                    officially recognized for
                                      requirements to building
                                                                     stormwater control in
                                       code for private sector7
                                                                   Seattle Code; City would     May violate state water    May violate state water          May help meet
                                                                   have to develop code or           rights laws                rights laws                drainage codes9
                                      Some homes may have                evaluate permit
                                       building code issues        applicants on a case-by-
                                       for bearing loads of
                                                                           case basis8
                                            green roofs


                                                                                                                                                       Interest of City Council
                                       Interest of City Council     Interest of City Council                                Interest of City Council     for other projects11:
                                                                                                Interest of City Council
                                         for other projects10:        for other projects11:                                    for other projects7:
                                                                                                   for other projects7:
                        Political                                                                                                                        SEA Street Initiative
                       Feasibility            City Hall              SEA Street Initiative                                 Fremont Rainharvesting         funded since 2001
                                                                                                  Seattle Rain Barrel
                                                                      funded since 2001                                         pilot project
                                           Ballard Library                                                                                             Northgate Mall Parking
                                                                                                                                                          Lot pilot project

                                      Low/Niche appeal; some        Moderate/High appeal;       Moderate/High appeal;       Moderate appeal; large High appeal; may depend
                     Aesthetics 12    may find landscaping the      depends on yard size,          relatively low          cistern may be obtrusive,      on porous
                                          roof appealing.            shape, and design             obtrusiveness            depending on lot layout      material used

 Total Per-Property Cost                     $33,810.00                    $816.67                     $153.02                    $1,392.00                   $7,978.13

*See next page for Appendix A notes
Appendix A Notes
      1 For a detailed description of the methodology used in these calculations, refer to Appendix C.

      2 Sholz-Barth, Katrin. "Green Roofs: Stormwater Management from the Top Down." Environmental Design &
        Construction Magazine Jan-Feb. 2001:1-11.

      3 EPA's Stormwater Technology Fact Sheet for Vegetated Swales:

      4 Rainwater Harvest Pilot Project Business Case FINAL 2003, pg.9

      5 City of Seattle website, SPU Services, Rain Barrel Program:

      6 Whole Building Design Guide Website, Design Guidance, Low Impact Development Technologies:

      7 website, "Sky Gardens- Travel in Landscape Architecture in Seattle, WA" by Linda Velazques,
        August/September 2004:

        Constructive Criticism: LEED green-building program confronts critics and growing pains by Ted S. Bowen, 10/26/05
        in Grist Magazine:

      8 City of Seattle website, "Sustainable Sites Prerequisite: Comparison of Seattle and [LEED] Reference Standard",
        Drainage Swales p 3:

      9 Seattle Department of Planning and Development Client Assistance Memo 515, Seattle Permits, Green Parking Lots:

     10 Puget Sound Action Team website, Green Building Programs:

     11 City of Seattle website, SEA Streets Project:
        City of Seattle website, Northgate Mall Pilot Project:
     12 Extensive searching yielded no information for aesthetics, so the analysis is based on subjective opinion.

     13 For the detailed analysis and cost breakdown, refer to Appendix B.

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