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~~~1 <br />3 Comments Page/Section Reference <br />Secfion 2-1-4, page 8 <br />The application.. states that stormwater impoundments (i.e. wet ponds) will be used to control <br />stormwater runoff and improve water quality. The application also states that stormwater <br />facilities will be designed in a manner to compliment buffers and open space. We .agree with <br />this approach, however we do not believe that the wet ponds shown will be adequate in <br />meeting stormwater requirements. <br />Under the Neuse Rules, new development cannot increase peak flaw leaving the site based <br />on predevelopment conditions for the 1-year, 24-hour storm. Additionally, the nitrogen load <br />leaving the site must be held to 3.6 Ibs per acre per year. <br />Based on the requested 70% impervious surface, staff does not believe the proposed ponds <br />can adequately treat runoff to meet the requirements listed above: Further, it is our <br />understanding that the in-lieu payment option to the North Carolina Ecosystem Enhancement <br />Program to meet the nitrogen loading requirement may not acceptable by North Carolina <br />Division of Water Quality, therefore on-site stormwater best management practices will be <br />required to meet the loading rate. <br />The application states that other innovative treatment approaches such as swales and bio- <br />retention areas, etc. will be considered to supplement fhe stormwater impoundments. Staff <br />believes that these aher approaches will be required to comply with the Neuse rule. <br />We view this as an opportunity to utilize low impact design for stormwater management. Using <br />L' ID techniques or "green infrastructure" can be very cost effective when compared to <br />traditional stormwater infrastructure. <br />We would like to work with the developer to come up with a stormwater master plan that will <br />treat stormwater in a sequence (i.e. "treatment train"). We suggest bioretention cells to be <br />integrated into the. landscape/buffer plan that would satisfy both stormwater and open space <br />requirements. Bioretention and other innovative measures could be installed on a "lot by ,lot" <br />basis, provided the overall stormwater management plan meets requirements. <br />Additionally, we suggest that rain harvesting be considered. Harvested stormwater runoff <br />could be utilized for~irrigation for landscaping and open space. <br />Resolved <br />Date <br />Comment sheet prepared by Terry Hackett, Water Resource Officer/Erosion Control Officer II <br />Department/Division Planning & Inspections/Erosion Control Division <br />Development Advisory Board Meeting Date: January 30, 2008 <br />2 <br />