08-09-1993 Council Packet - Laserfiche WebLink

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seven days, and the stormdrain inlets must be protected wth straw bale or other appropriate filtering barriers. 5;tnrm water manageme nt criteria for permanent faciliti es. i\ An aoDlicant shall install or construct, on or for the proposed land disturbing or ^ development activity, all storm water management facilities necessary to manage increased runoff so that the two-year, ten-year, and 100-year storm peak discharge rztcs existing before the proposed development shall not be incre^cd ^d accelerated channd erosion will not occur as a result of the proposed land disturbing or development activity. An applicant may also make an in-kind or monetary contribution to the development and maintenance of community storm water management facilities designed to serve multiple land disturbing and development activities undertaken by one ^ or more persons, including the applicant — C* The applicant shall give consideration to reducing the need for sjorm water management facilities by incorporating the use of natural topography and land cover such as wetlands, ponds, natural swales and depressions « they exist oefore development to the degree that they can accommodate the additional flow of water without compromising the integrity or quality of the wetland or pond. The following storm water management practices shall be investigated in developing a storm water management plan in the following descending order of preference: (5|) Natural infiltration of runoff precipitation on-site, if ouitable soil conditions afo avoilablo for use; (COMMENTARY: The purpose ohhis provision is to encourage the development o[ a storm w/i i»r mnna nment plan thahtne oura^es natural infiltration. This inclines nmvidinv js much natural or ve^ctated^na s on the site as possible, minimam g imperviouTsurfaces. and directing rUftoff to^eetated areas rather than to adiomms streets, storm sewers and ditchesfl Fow attenuation by use of open vegetated swales and natural depressions; 3) Storm water retention facilities; and (i) Storm water detention facilities. ij) A combination of successive practices may be used to achieve the applicable minimum I control requirements specified in subsection (I) above. Justification shall be provi by the applicant for the method selected. ' jSn ^ Design standards . Storm water detention facilities constructed in the [City, Townr-Qwuiy] of shall be designed according to the most current technology as reflected in i c MPCA publication ‘Protecting Water Quality in Urban Areas", and shall contain, a a minimum, the following design factors: I) A permanent pond surface area equal to two percent of the impervious area draining to the pond or one percent of the entire area draining to the pond, whichever amount is greater; 2) An average permanent pool depth of four to ten feet; [COMMENTARY: An alternative to subsections (a) and (b) would be to require that the %