2320 RAILWAY AVE INTERWEST CONSTRUCTION INC 2023-06-12

INTERWEST — EVERETT CONTRACTOR'S YARD INTERIM FILL PROJECT Sitts & Hill Engineers, Inc. CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN Job Number 17,733 or blanket. If the erosion problem is drainage related, then the problem shall be fixed and the eroded area remulched. Table 11-4.1.8 Mulch Standards and Guidelines Mulch Quality Application Remarks Material Standards Rates Cost-effective protection when applied with adequate thickness. Hand -application generally requires greater thickness than blown straw. The thickness of straw may be reduced by half when used in conjunction with seeding. In windy areas Air-dried; 2' -3" thick; straw must be held in place by crimping, using a free from 5 bales per tackifier, or covering with netting. Blown straw Straw undesirable 1,000 sf or always has to be held in place with a tackifier as seed and 2-3 tons per even light winds will blow it away. Straw, how - coarse ever, has several deficiencies that should be con - material. acre sidered when selecting mulch materials. It often introduces and/or encourages the propagation of weed species and it has no significant long-term benefits It should also not be used within the ordinary high-water elevation of surface waters (due to flotation). Approx. 25- Shall be applied with hydromulcher. Shall not be No growth 30 Ibs per used without seed and tackifier unless the applic- Hydromulch inhibiting 1,000 sf or 1.500 ation rate is at least doubled. Fibers longer than factors. 2,000 Ibs about 3/4 - 1 inch clog hydromulch equipment. Fibers should be kept to less than 3/4 inch. per acre No visible water or More effective control can be obtained by increas- dust during ing thickness to 3". Excellent mulch for protecting handling. 2" thick final grades until landscaping because it can be Must be pro in.; directly seeded or tilled into soil as an amend- duced per approx. 100 ment. Compost used for mulch has a coarser size Compost WAC 173- tons per gradation than compost used for BMP C125: Top- 350, Solid acre soiling / Composting (p.297) or BMP T5.13: Post - Waste (approx. Construction Soil Quality and Depth (p.911). It is more stable and practical to use in wet areas and Handling 800 Ibs per Standards, yard) during rainy weather conditions. Do not use near but may wetlands or near phosphorous impaired water have up to bodies. 35% 2014 Stormwater Management Manual for Western Washington Volume 11 - Chapter 4 - Page 286 SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON 38