Implementing Low Impact Design on Large Projects

Obtaining approval to use LID techniques in communities that have not seen or approved them is not always an easy task. The stormwater and zoning regulations may not be set up to grant approval without a lot of proof and discussion. Owners, municipal regulators and other consultants need to be convinced the systems are economical and can be maintained. This presentation will include some of the steps required to gain approval to use LID by the owner, the community, and the engineering review authorities, as well as the financial savings and opportunities of implementing LID. Two projects will be reviewed including a 45 acre suburban hospital site with 28 vegetated stormwater collection areas, 26 grassed detention basins, 5 wetland swales, and 5 extended wetland detention basins. The second site is a 119 acre suburban high school site which had to meet new state regulations limiting the annual infiltration volume for the developed site to the existing annual infiltration volume. This site includes the design of 22 parking island and other basin rain gardens, 3 water quality wetland basins to treat the first 1" of runoff, 9 wetland conveyance channels, 2 vegetated basins, and 1 extended wetland detention basin. The entire system daylighted over 3000 If of farm tiles and created over 8000 If of open channel and basin flow across the site.