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1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />L� i <br />1 <br />H <br />1 <br />1 <br />7 <br />1 <br />1 <br />r <br />areas shall drain to a sediment pond. <br />. Areas less than 5 acres shall drain to sediment control BMPs, such as a minimum <br />of 3 check dams per acre. The total number of check dams used shall be max- <br />imized to achieve the greatest amount of settlement of sediment prior to dis- <br />charging from the site. Each check dam shall be spaced evenly in the drainage <br />channel through which stormwater flows are discharged off -site. <br />• On all sites, the use of silt fence shall be maximized to limit the discharges of sed- <br />iment from the site. <br />• All areas not being actively worked shall be covered and protected from rainfall. <br />PAM shall not be the only cover BMP used. <br />• PAM can be applied to wet soil, but dry soil is preferred due to less sediment loss. <br />• PAM will work when applied to saturated soil but is not as effective as applications <br />to dry or damp soil. <br />. Keep the granular PAM supply out of the sun. Granular PAM loses its effectiveness <br />in three months after exposure to sunlight and air. <br />. Proper application and re -application plans are necessary to ensure total effect- <br />iveness of PAM usage. <br />. PAM, combined with water, is very slippery and can be a safety hazard. Care must <br />be taken to prevent spills of PAM powder onto paved surfaces. During an applic- <br />ation of PAM, prevent over -spray from reaching pavement as pavement will <br />become slippery. If PAM powder gets on skin or clothing, wipe it off with a rough <br />towel rather than washing with water -this only makes cleanup messier and take <br />longer. <br />Some PAMs are more toxic and carcinogenic than others. Only the most envir- <br />onmentally safe PAM products should be used. <br />The specific PAM copolymer formulation must be anionic. Cationic PAM shall not <br />be used in any application because of known aquatic toxicity problems. Only <br />the highest drinking water grade PAM, certified for compliance with ANSI NSF <br />Standard 60 for drinking water treatment, will be used for soil applications. Recent <br />media attention and high interest in PAM has resulted in some entrepreneurial <br />exploitation of the term "polymer." All PAM are polymers, but not all polymers are <br />PAM, and not all PAM products comply with ANSI NSF Standard 60. PAM use <br />shall be reviewed and approved by the local permitting authority. <br />PAM designated for these uses should be "water soluble" or "linear" or "non -cross - <br />linked". Cross -linked or water absorbent PAM, polymerized in highly acidic (pH<2) <br />conditions, are used to maintain soil moisture content. <br />• The PAM anionic charge density may vary from 2-30 percent; a value of 18 percent <br />2014 Stormwater Management Manual for Western Washington <br />Volume 11 - Chapter 4 - Page 303 <br />