10521 19TH AVE SE 2022-05-23 - Laserfiche WebLink

Soil Treatment Options There are four Soil Treatment Options that can be used to meet the post - construction soil standard. These options can be used individually, or in combination (more than one may be used in different areas of a single site), so that they work best for the situation. The most convenient and economical methods for achieving the standards depend on site soil conditions, grading and subgrade compaction, practicality of stockpiling site topsoil during grading, and site access issues. Choose Options 1, 2, 3 and/or 4 in areas where grading and soil disturbance are unavoidable, and follow the attached design guidelines Option 1: Leave native soil undisturbed, and protect from compaction during con- struction. NOTE: Option 1 is only applicable to sites that have the original, undisturbed soil native to the site. This will most often be forested land that is being left un- disturbed in the current project. This option is the most economical and best for the environment, but is not always feasible. Plan site development to leave areas where native vegetation does not need to be dis- turbed. -Option 2: Amend disturbed soil according to the following procedures: a. Scarify subsoil to a depth of one foot. b. In planting beds, place three inches of com- post and till in to an eight -inch depth. In turf areas, place two inches of compost and till in to an eight -inch depth. Apply two to four inches of arborist wood chip, coarse bark mulch, or compost mulch to planting beds after final planting. Alternatively, disturbed soil can be amended on a site -customized manner so that it meets the soil quality criteria set forth above, as deter- mined by a licensed engineer, geologist, land- scape architect, or other person as approved by Snohomish County. Note: MR S is triggered on sites with more than 2, 000 sq. ft. of new, replaced, or new plus replaced impervious surface, or 7, 000 sq. ft. or greater of land disturbing activity.