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INTERWEST — EVERETT CONTRACTORS YARD INTERIM FILL PROJECT Sitts & Hill Engineers, Inc. <br />I <br />CONSTRUCTION STORMINA TER POLLUTION PREVENTION PLAN Job Number 17,733 <br />drain inlets shall be protected to prevent sediment -laden water ng the <br />' storm system (see BMP C220: Storm Drain Inlet Protectio . 57 . <br />Maintenance Stan a <br />' Inspect stabilized areas regularly, a ally arge storm events. <br />Crushed rock, gravel base, etc., sh adde quired to maintain a stable driving <br />' surface and to stabilize any that have eroded. <br />Following constru ' ,these areas shall be restored to pre -con on condition or bet- <br />ter to preve ure erosion. <br />' P rm street cleaning at the end of each day or more often if necessary. <br />BMP C120: Temporary and Permanent Seeding <br />' Purpose <br />Seeding reduces erosion by stabilizing exposed soils. A well -established vegetative <br />' cover is one of the most effective methods of reducing erosion. <br />Conditions of Use <br />Use seeding throughout the project on disturbed areas that have reached final grade or <br />that will remain unworked for more than 30 days. <br />The optimum seeding windows for western Washington are April 1 through June 30 and <br />September 1 through October 1. <br />Between July 1 and August 30 seeding requires irrigation until 75 percent grass cover is <br />established. <br />Between October 1 and March 30 seeding requires a cover of mulch with straw or an <br />erosion control blanket until 75 percent grass cover is established. <br />' Review all disturbed areas in late August to early September and complete all seeding <br />by the end of September. Otherwise, vegetation will not establish itself enough to <br />provide more than average protection. <br />' - Mulch is required at all times for seeding because it protects seeds from heat, mois- <br />ture loss, and transport due to runoff. Mulch can be applied on top of the seed or <br />simultaneously by hydroseeding. See BMP C121: Mulching (p.284) for spe- <br />cifications. <br />- Seed and mulch, all disturbed areas not otherwise vegetated at final site sta- <br />bilization. Final stabilization means the completion of all soil disturbing activities at <br />' the site and the establishment of a permanent vegetative cover, or equivalent per- <br />' 2014 Stormwater Management Manual for Westem Washington <br />Volume ll - Chapter 4 - Page 278 <br />SITTS & HILL ENGINEERS, INC. 30 <br />' TACOMA, WASHINGTON <br />