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CITY OF EVERETT STORMWATER MANAGEMENT MANUAL <br /> 4. Topsoil shall not be placed while in a frozen or muddy condition, when the subgrade is <br /> excessively wet, or when conditions exist that may otherwise be detrimental to proper grading or <br /> proposed sodding or seeding. <br /> 5. Previously established grades on the areas to be topsoiled shall be maintained according to the <br /> approved plan. <br /> 6. When native topsoil is to be stockpiled and reused the following should apply to ensure that the <br /> mycorrhizal bacterial, earthworms, and other beneficial organisms will not be destroyed: <br /> a. Topsoil is to be reinstalled within 4 to 6 weeks <br /> b. Topsoil is not to become saturated with water <br /> - c. Plastic cover is not allowed. <br /> - Maintenance Sfandards <br /> ' Inspect stockpiles regularly, especially after large storm events. Stabilize any areas that have eroded. <br /> 3.2.13 BMP C126: Polyacrylamide for Soil Erosion Protection <br /> Purpose <br /> Polyacrylamide (PAM) is used on construction sites to prevent soil erosion. <br /> Applying PAM to bare soil in advance of a rain event significantly reduces erosion and controls sediment <br /> in two ways. First, PAM increases the soil's available pore volume, thus increasing infiltration through <br /> flocculation and reducing the quantity of stormwater runof£ Second, it increases flocculation of <br /> suspended particles and aids in their deposition, thus reducing stormwater runoff turbidity and improving <br /> water quality. <br /> Conditions of Use <br /> l. PAM shall not be directly applied to water or allowed to enter a water body. <br /> 2. Some PAMs are more toxic and carcinogenic than others. Only the most environmentally safe <br /> PAM products should be used. <br /> 3. The specific PAM copolymer formulation must be anionic. Cationic PAM shall not be used in <br /> any application because of known aquatic toxicity problems. Only the highest drinking water <br /> grade PAM, certified for compliance with ANSI/NSF Standard 60 for drinking water treatment, <br /> shall be used for soil applications. PAM use shall be reviewed and approved by the City. The <br /> _ Washington State Department of Transportation (WSDOT) has listed approved PAM products on <br /> their Web site. <br /> ' 4. In areas that drain to a sediment pond, PAM can be applied to bare soil under the following <br /> � conditions: <br /> a. During rough grading operations <br /> b. Staging areas <br /> c. Balanced cut and fill earthwork <br /> d. Haul roads prior to placement of crushed rock surfacing <br /> e. Compacted soil roadbase <br /> f. Stockpiles <br /> g. After final grade and before paving or final seeding and planting <br /> Volume 11— Construction Stormwater Pollution Prevention <br /> 3-22 <br />