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129 <br /> 3) New vegetation shall be planted to capture non-source pollutants before they <br /> reach the perennial stream, as per applicable Orange County Standards. <br /> d) Calculating Width of Stream Buffer <br /> 1) How to Calculate Slope <br /> a. Draw a line perpendicular to the stream. <br /> b. Determine the elevation at the stream itself (1), and at the point 250' <br /> from the stream along the perpendicular line (2). <br /> c. Subtract (1) from (2). <br /> d. Divide c. by 250. <br /> e. Multiple d. by 100 <br /> Hereinafter, the number derived in e. will be referred to as "slope value". <br /> 2) Method A - Stream Buffer Based on Slope <br /> The width of the buffer shall be fifty (50) feet from each edge of the floodplain, <br /> plus the slope value multiplied by four. <br /> 3) Method B - Stream Buffer Based on Slope and Groundcover <br /> STREAM BUFFER WIDTH (IN FEET) <br /> BASED ON SLOPE AND GROUNDCOVER <br /> Slope Value Type of Groundcover <br /> Grass Woods <br /> • <br /> 2 to 4.9 100 50 <br /> 5to9.9 150 100 <br /> 10 to 14.9 200 100 <br /> 15 or greater 250 150 <br /> In addition to the buffer zone resulting from the calculations below, a stream buffer shall include <br /> any portion of a floodplain as defined in the Orange County Flood Damage Prevention <br /> Ordinance, by special survey by a registered engineer or surveyor, or by alluvial soils as <br /> designated in the Orange County Soils Survey. <br /> 'The required stream buffer zone shall not be limited to one calculation, but shall be based on <br /> calculations made at points where topographical and ground cover conditions change based on an <br /> analysis of the site. <br /> 13 <br />