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Orange County SE & SC Ordinance °^^«^~P.~~.,be: '-.~=6'B~September 12.20tJ6 <br />2. Standards for High Quality Waters <br />In High Quality Water (HQW) zones the following design standards shall apply: <br />a. Uncovered areas in HQW zones shall be limited at any time to a <br />maximum total area of 20 acres within the boundaries of the tract. <br />Only the portion of the land-disturbing activity within a HQW zone <br />shall be governed by this section. Larger areas may be uncovered <br />within the boundaries of the tract with the written approval of the <br />Director of the Division of Land Resources of the Department of <br />Environment, Health, and Natural Resources. <br />Erosion and sedimentation control measures, structures, and devices <br />within HQW zones shall be so planned, designed, and constructed <br />to provide protection from the runoff of the 25-year storm which <br />produces the maximum peak rate of rnnoff. The peak rate of runoff <br />shall be calculated according to procedures in the United States <br />Department of Agriculture Soil Conservation Service's National <br />Engineering Field Manual for Conservation Practices or according <br />to procedures adopted by any other agency of this state or the <br />United States or any generally recognized organization or <br />association. <br />c. Sediment ponds (also called "sediment basins") within HQW zones <br />shall be designed and constructed such that the pond will have a <br />settling efficiency of at least 70% for the 40 micron (0.04 mm) size <br />soil particle transported into the basin by the runoff of that 2-year <br />storm which produces the maximum peak rate of runoff The peak <br />rate of runoff shall be calculated according to procedures in the <br />United States Department of Agriculture Soil Conservation <br />Service's National Engineering Field Manual for Conservation <br />Practices or according to procedures adopted by any other agency <br />of this state or the United States or any generally recognized <br />organization or association. <br />d. Newly constructed open channels in HQW zones shall be designed <br />and constructed with side slopes no steeper than 2 horizontal to 1 <br />vertical if a vegetative cover is used fox stabilization unless soil <br />conditions permit a steeper slope or where the slopes are stabilized <br />by using mechanical devices, structural devices or other acceptable <br />devices. In any event, the angle for side slopes shall be sufficient to <br />restrain accelerated erosion. <br />e. Ground cover sufficient to restrain erosion must be provided for <br />any portion of a land disturbing activity in a HQW zone within 15 <br />working days or 60 calendar days, whichever period is shorter, <br />following completion of construction or development. <br />1S <br />