Ordinance - #14-09 - 09/23/2014 - Laserfiche WebLink

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used must conform to current Lower Rum River Watershed Management Organization (LRRWMO) rules. Z. Lowest Floor Elevation -The Lowest floor elevation of all development, including basements, must be at least 3 feet above the highest anticipated groundwater table, 2 feet above the designated or designed 100 -year flood elevation or 1 foot above the emergency overflow, whichever is higher. The LRRWMO rules designate a procedure for modifying these requirements. preference: sewers .,a dit for the method selected. Storm water volume management practices must be utilized on all new development sites. The options are: (1) Infiltrating or retaining the first one (1) inch of precipitation over the impervious surface of the site. These practices should seek to utilize pervious areas for stormwater treatment and to infiltrate stormwater runoff from driveways, sidewalks, rooftops, parking lots and landscaped areas to the maximum extent practical to provide treatment for both water quantity and quality. (2) Retain the post construction runoff volume on the site for the 95th percentile storm. These practices shall prevent the off -site discharge of the precipitation from all rainfall events less than or equal to the 95th percentile rainfall event. Discharge volume reduction can be achieved by engineered infiltration, canopy interception, soil amendments, evaporation, rainfall harvesting, and /or evapotranspiration and any combination of the aforementioned practices. (3) Match the pre- development runoff conditions. Design and construct stormwater management practices that preserve the pre - development runoff conditions following construction. The post - construction rate, volume, and duration of discharges must not exceed the pre - project rates and the pre - project hydrograph for the 1 and 2 year storms must be replicated through the site design and other appropriate processes. The practices listed above can be used to achieve this goal. Defensible and consistent hydrological assessments and modeling methods must be used and documented.