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EROSION CONTROL ELEMENT # 6 - Protect Slopes <br />Requirements — Protect Slopes <br />1. Off -site stormwater (run-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 />❑ Temporary & PmTment Seeding BMP C 120 <br />✓ Surface RougheningBMP C130 <br />❑ Gradient Terraces —BMP C 131 <br />✓ Interceptor dike and swaleBMP C200 <br />❑ Grass -Lined Channels-- BMP C201 <br />❑ Pipe slope Drains — BMP C204 <br />❑ Subsurface Drains BMP C205 <br />❑ Level Spreader—BMP C206 <br />✓ Check DamsBMP C207 <br />❑ Triangular Silt Dike (Geotextile-Encased Check Dam) <br />❑ Other <br />❑ Not Applicable— See explanation below. <br />BMP C 208 <br />12 <br />