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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 C 126: 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 II-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 II-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 II-3.5: Size Gradations of Compost as Mulch Material <br />Sieve Size <br />Percent Passing <br />3" <br />100% <br />1" <br />90% -100% <br />3/4" <br />70% - 100% <br />1/4" <br />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 ll - Chapter 3 - Page 290 <br />