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January 28, 2010 7 093�93256.100 <br />excessive erosion oaurs during the wet season, erosion control nets or blankets will be placed as <br />needed to stal�ilize the prohlem area. <br />3.6 Element 3t6 - Protect Slopes <br />All slopes will be designed, constructed, and proteded in a manner ihal minim¢es erosion. The slopes <br />potentially subjecl to erosion include the weslern portions o( the penmeler drainage dltches, slopes <br />associated with the access ramp located at the soulhwest corner of Bie cap, and the 6H:1V slope on the <br />west side of the wp. These slopes will be seeded and mulched as described in the Design Drawings <br />specificati ���s. As necessary, Ihe foilowing specific BMPs will be u��ed to protect siopes tor thls project. <br />"1 Temporary and Permanent Seeding (BMP C120) <br />■ Mulching(BMPC121) <br />■ Nets and Blankets (BMP C122) <br />■ Plastic Covenng (BMP CI23) <br />■ Interceptor Dike and Swale (BMP C200) <br />■ Materials on Hand (BMP C150) <br />Slopes will be temporenly seeded, covered with plastic, or otherwise stabilized if permanent seedmg <br />has not been establlshed prior to the wet season. Temporary or permanent seed will be app6ed early <br />enough to achieve germination prior to the wet season. II excessive erosion occurs during lhe wet <br />season, erosion control nets or blankets wiil be placed as needed to stabilize the probiem area. <br />3.7 Element #7 - Protect Drain Inlets <br />BMPs tor prolection of drain inlets are not required for this project. There are no storm drain inlets or <br />culverts in ihe vicinity of Ihe site. <br />3.8 Element #8 - Stabilize Channels and Outlets <br />Where site runoff is conveyed in the proposed perimeter ditches, BMPs will be implemented to prevenl <br />channel eroslon. The specific BMPs for channel stabilization that wdl be used on this project include. <br />■ Temporary and Permanent Seeding (BMP C120) <br />■ Grass-Lined Channels (BMF' C201) <br />■ Channel Lming (BMP C202) <br />Check Dams (BMP 207)The project site is located west of Ihe Cascade Mountain Crest. As such, all <br />lemporary on-site convuyancr channels have been designed to prevent erosion from the expecled peak <br />10-mmute velocity of (low Irom a Type IA, 10-year, 24-hour recurrence mterval slorm 1or the deveioped <br />condition. For this project, the calculated velocity is less lhan 1 fUsec tor Ihis event S�andard practice <br />indicales thal soi� channels can accommodate velocities up to about 5 fUsec wilhout signdicant erosion, <br />and therefore no additional temporary lining is required for this projed. As a back•up measure, sill fence <br />OI:B�Cm: G�tpaaes.;r'pcm <br />