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• compost; <br /> . or blends of these. <br /> Tackifier shall be plant-based, such as guar or alpha plantago, or chemical-based such as poly- <br /> acrylamide or polymers. <br /> Generally, mulches come in 40-50 pound bags. Seed and fertilizer are added at time of application. <br /> Recycled cellulose may contain polychlorinated biphenyl (PCBs). Ecology recommends that <br /> products should be evaluated for PCBs prior to use. <br /> Refer to BMP C126: Polyacrylamide(PAM)for Soil Erosion Protection for conditions of use. PAM <br /> shall not be directly applied to water or allowed to enter a water body. <br /> Any mulch or tackifier product used shall be installed per the manufacturer's instructions. <br /> Design and Installation Specifications <br /> For mulch materials, application rates,and specifications,see Table 11-3.6: Mulch Standards and <br /> Guidelines. Consult with the local supplier or the local conservation district for their recom- <br /> mendations. Increase the application rate until the ground is 95%covered (i.e. not visible under the <br /> mulch layer). Note:Thickness may be increased for disturbed areas in or near sensitive areas or <br /> other areas highly susceptible to erosion. <br /> Where the option of"Compost"is selected, it should be a coarse compost that meets the size grad- <br /> ations listed in Table 11-3.5: Size Gradations of Compost as Mulch Material when tested in accord- <br /> ance with Test Method 02.02-B found in Test Methods for the Examination of Composting and <br /> Compost(Thompson, 2001). <br /> Table 11-3.5: Size Gradations of Compost as Mulch Material <br /> Sieve Size Percent Passing <br /> 3" 100% <br /> 1" 90%-100% <br /> 3/4" 70%-100% <br /> 1/4" 40%-100% <br /> Mulch used within the ordinary high-water mark of surface waters should be selected to minimize <br /> potential flotation of organic matter. Composted organic materials have higher specific gravities <br /> (densities)than straw,wood, or chipped material. Consult the Hydraulic Permit Authority(HPA)for <br /> mulch mixes if applicable. <br /> Maintenance Standards <br /> The thickness of the mulch cover must be maintained. <br /> Any areas that experience erosion shall be remulched and/or protected with a net or blanket. If the <br /> erosion problem is drainage related,then the problem shall be fixed and the eroded area remulched. <br /> 2019 Stormwater Management Manual for Western Washington <br /> Volume 11-Chapter 3-Page 290 <br />