1622 E MARINE VIEW DR WHOLE SITE 2022-02-01

C7 • • Table 4.1.8 Mulch Standards and Guidelines Application Mulch Material Quality Standards Rates Remarks Straw Air-dried; free from 2"-3" thick; 5 Cost-effective protection when applied with adequate thickness. undesirable seed and bales per 1,000 Hand -application generally requires greater thickness than coarse material. sf or 2-3 tons per blown straw. The thickness of straw may be reduced by half acre when used in conjunction with seeding. In windy areas straw must be held in place by crimping, using a tackifier, or covering with netting. Blown straw always has to be held in place with a tackifier as even light winds will blow it away. Straw, however, has several deficiencies that should be considered 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). Hydromulch No growth Approx. 25-30 Shall be applied with hydromulcher. Shall not be used without inhibiting factors. lbs per 1,000 sf seed and tackifier unless the application rate is at least doubled. or 1,500 - 2,000 Fibers longer than about 3/4-1 inch clog hydromulch equipment. lbs per acre Fibers should be kept to less than3/4 inch. Composted No visible water or 2" thick min.; More effective control can be obtained by increasing thickness Mulch and dust during approx. 100 tons to 3". Excellent mulch for protecting final grades until Compost handling. Must be per acre (approx. landscaping because it can be directly seeded or tilled into soil produced in 800 lbs per yard) as an amendment. Composted mulch has a coarser size accordance with gradation than compost. It is more stable and practical to use in WnC 173-350, wet areas and during rainy weather conditions. Do not use Solid Waste composted mulch near wetlands or near phosphorous impaired Handling Standards. water bodies. Chipped Site Average size shall 2" thick min.; This is a cost-effective way to dispose of debris from clearing Vegetation be several inches. and grubbing, and it eliminates the problems associated with Gradations from burning. Generally, it should not be used on slopes above fines to 6 inches in approx. 10% because of its tendency to be transported by length for texture, runoff. It is not recommended within 200 feet of surface waters. variation, and If seeding is expected shortly after mulch, the decomposition of interlocking the chipped vegetation may tie up nutrients important to grass properties. establishment. Wood -based No visible water or 2" thick min.; This material is often called "hog or hogged fuel." The use of Mulch or Wood dust during approx. 100 tons mulch ultimately improves the organic matter in the soil. Straw handling. Must be per acre (approx. Special caution is advised regarding the source and composition purchased from a 800 lbs. per of wood -based mulches. Its preparation typically does not supplier with a Solid cubic yard) provide any weed seed control, so evidence of residual Waste Handling vegetation in its composition or known inclusion of weed plants Permit or one or seeds should be monitored and prevented (or minimized). exempt from solid waste regulations. Wood Strand A blend of loose, 2" thick min. Cost-effective protection when applied with adequate thickness. Mulch long, thin wood A minimum of 95-percent of the wood strand shall have lengths pieces derived from between 2 and 10-inches, with a width and thickness between native conifer or 1/16 and %-inches. The mulch shall not contain resin, tannin, or deciduous trees with other compounds in quantities that would be detrimental to plant high length -to -width life. Sawdust or wood shavings shall not be used as mulch. ratio. (WSDOT specification (9-14.4(4)) Volume H — Construction Stormwater Pollution Prevention - August 2012 4-21