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Condition <br />Water Bodies with Piped <br />Outlets (includes graded <br />areas that will create <br />goaded conditions <br />during the 100 -yr storm <br />event) <br />Landlocked Water <br />Bodies <br />Flowing Channels Passing <br />Through Roadways <br />New Road Construction (low <br />point in roadway) <br />No Lower than the 100 -yr <br />flood level <br />1 foot above the 100- <br />yr 24 -hr elevation <br />No lower than the 50 -yr <br />flood level, Overflow swale <br />for flows over the 50 -yr <br />flood level to protect <br />downstream roadway <br />embankment <br />Existing ow <br />g Roadwa s y ( p oint in <br />roadway) <br />If the existing road is <br />below the 100 -yr flood <br />level, the community <br />should require a variance <br />for the road. This will <br />allow for proper review of <br />safety standards. <br />No lower than 10 <br />inches below 100 -yr <br />24 -hr elevation <br />No lower than the 50 -yr <br />flood level. <br />New construction and additions <br />to existing structures (low floor <br />elevation and lowing opening of <br />building) <br />(NOTE: Areas delineated as a <br />state approved FEMA floodplain <br />ordinance will likely have <br />additional standards for the <br />lowest floor including basement <br />elevations in the ordinance. if <br />the structure is in a floodplain, <br />often thefloodplain ordinance <br />will have more restrictive <br />standards requiring the lowest <br />flow including basement <br />elevation to start at one foot <br />above the mapped 100 year <br />floodplain) <br />Minimum of 3 feet above <br />100 -yr, 24 -hr stonn event. Additional <br />recommendations: <br />1. At least I foot above the <br />emergency overflow <br />elevation. <br />2. At least 4 feet above <br />normal groundwater <br />elevation. <br />3. At least 2 feet above <br />hydrie or mottled soils <br />elevation. <br />Minimum of 5 feet <br />above 100 -yr 24 -hr <br />elevation. <br />N/A <br />Existing Structures (low floor <br />elevation and low opening of <br />building) <br />Existing structures should <br />require a proper review of <br />safety standards, but in <br />any event must be a <br />minimum of 2 feet above <br />the 100 -yr, 24 -hr storm <br />event. <br />Minimum of 5 feet <br />above 100 -yr 24 -hr <br />elevation. <br />N/A <br />age Break <br />Page, 11: [8] Deleted <br />Lee Elfering <br />4'- 10/15/2006 8:38:00 PM <br />Special Waters Requirements <br />There shall be no increase in either the volume or rate of stormwater <br />runoff for the one and two year 24 -hour storm event including trout <br />streams. <br />If the soil is not suitable for stormwater infiltration and/or <br />evaporation/transpiration techniques (soils with permeability values <br />less that HSG C soils (less than 2.5 inches per hour) as defined by the <br />Natural Resources Conservation Service), the community may require <br />reduced volume control. <br />- 3 3 - <br />