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EROSION CONTROL ELEMENT#6-Protect Slopes <br /> Requirements—Protect Slopes <br /> 1. Off-site stormwater(nun-on)shall be diverted away from slopes and disturbed areas with <br /> interceptor dikes and/or swales.Off-site stormwater should be managed separately from <br /> stormwater generated on the site. <br /> 2. At the top of slopes drainage shall be collected in pipe slope drains or protected channels <br /> to prevent erosion.Temporary pipe slope drains shall handle the peak flow from a 10 <br /> year,24 hour event assuming a Type IA rainfall distribution.Alternatively,the 10- <br /> year and 25-year, 1-hour flow rates indicated by an approved continuous runoff <br /> model,increased by a factor of 1.6,may be used. Consult the Utilities Engineering <br /> Standards for sizing PERMANENT pipe slope drains. <br /> 3. Provide drainage to remove ground water intersecting the slope surface of exposed <br /> soil areas.Excavated material shall be placed on the uphill side of trenches,consistent <br /> with safety and space considerations. <br /> 4. Check dams shall be placed at regular intervals within channels that are cut down a <br /> slope.(Show a detail on TESC plan if this technique is to be used onsite.)Soils <br /> shall be stabilized as specified in Element#5. <br /> 5. Minimize cut slope length and steepness. Slope surfaces shall be roughened. <br /> Consider soil type and its potential for erosion. Reduce slope runoff velocities by reducing <br /> the continuous length of slope with terracing and diversions,reduce slope steepness,and <br /> roughen slope surface. <br /> The following Best Management Practices,(BMPs),the ones that the Contractor will implement on <br /> site,to meet the erosion control requirements listed above: <br /> U Temporary&Permanent Seeding—BMP C120 <br /> ✓ Surface Roughening—BMP C130 <br /> U Gradient Terraces—BMP C 131 <br /> ✓ Interceptor dike and swale—BMP C200 <br /> U Grass-Lined Channels—BMP C201 <br /> ❑ Pipe Slope Drains—BMP C204 <br /> ❑ Subsurface Drains—BMP C205 <br /> ❑ Level Spreader—BMP C206 <br /> ✓ Check Dams—BMP C207 <br /> U Triangular Silt Dike (Geotextile-Encased Check Dam)— BMP C 208 <br /> ❑ Other <br /> U Not Applicable—See explanation below. <br /> 11 <br />