3800 RIVERFRONT BLVD 2025-07-23 - Laserfiche WebLink

1 concerning its acceptance of this guidance. It is available through the organization, Soils for Salmon. As of this printing the document may be found at: hftp://www.soils- forsalmon.org/pdf/Soil BMP Manual. df. . The final composition and construction of the soil system will result in a natural selection or favoring of certain plant species over time. For example, incorporation of topsoil may favor grasses, while layering with mildly acidic, high -carbon amend- ments may favor more woody vegetation. . Allow sufficient time in scheduling for topsoil spreading prior to seeding, sodding, or planting. . Take care when applying to soil to subsoils with contrasting textures. Sand top- p 9 Y P soil over clayey subsoil is a particularly poor combination, as water creeps along soil the junction between the soil layers and causes the topsoil to slough. If topsoil and subsoil are not properly bonded, water will not infiltrate the soil profile evenly and it will be difficult to establish vegetation. The best method to prevent a lack of bond- ing is to actually work the topsoil into the layer below for a depth of at least 6 inches. . Field exploration of the site shall be made to determine if there is surface soil of suf- ficient quantity and quality to justify stripping. Topsoil shall be friable and loamy (loam, sandy loam, silt loam, sandy clay loam, and clay loam). Avoid areas of nat- ural ground water recharge. • Stripping shall be confined to the immediate construction area. A 4-inch to 6-inch stripping depth is common, but depth may vary depending on the particular soil. All surface runoff control structures shall be in place prior to stripping. . Do not place topsoil while in a frozen or muddy condition, when the subgrade is excessively wet, or when conditions exist that may otherwise be detrimental to proper grading or proposed sodding or seeding. . In any areas requiring grading remove and stockpile the duff layer and topsoil on site in'a designated, controlled area, not adjacent to public resources and critical areas. Stockpiled topsoil is to be reapplied to other portions of the site where feas- ible. . Locate the topsoil stockpile so that it meets specifications and does not interfere with worts on the site. It may be possible to locate more than one pile in proximity to areas where topsoil will be used. 1 Stockpiling of topsoil shall occur in the following manner: • Side slopes of the stockpile shall not exceed 2H:lV. . Between October 1 and April 30: 1 2014 Stormwater Management Manual for Western Washington Volume // - Chapter 4 - Page 299