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:l <br />FIELD GUIDE TO VERIFYING SOIL QUALITY AND DEPTH <br />� IN NEW LANDSCAPES <br />This guide is provided to help professional <br />inspectors verify implementation of soil <br />improvements to fulfill BMP T5.13 "Post <br />Construction Soil Quality and Depth" in the <br />Washington Department of Ecology's <br />Stormwater Management Manual Western <br />Washington. <br />The main conditions to be confirmed are: <br />1. Provision of eight inches of topsoil containing 10% <br />organic matter in planting beds, or 5% in turf areas. <br />2. Scarification of compacted subsoil four inches below <br />the topsoil layer (for a total uncompacted depth of 12 <br />inches). <br />3. Placement of two inches of mulch on all planting <br />beds. <br />Site Inspection Supplies <br />• A copy of the approved Soil Management Plan (SMP) for <br />the site, with site drawing. <br />• A sturdy shovel <br />• Tape measure or 12" ruler <br />• 3/8 inch diameter 3-4 foot stainless steel "rod <br />penetrometer" with a 1/8" bevel cut into the tip at 30 <br />degrees from the side, and a 90 degree bend at top to form <br />a handle (see illustration, next page). <br />• Field Verification Form to record results <br />The following steps may be completed at multiple visits <br />as a project progresses or in one final project approval <br />inspection, depending on local practices: <br />STEP 1: Compare site conditions with approved <br />Soil Management Plan (SMP). <br />The SMP approved with the site permit describes soil <br />treatments approved for each area. Make sure site <br />conditions match these details in the SMP: <br />• Site location and permit holder. <br />• Turf and planting areas match approved drawings. <br />• Areas to remain as undisturbed native soil and <br />vegetation have been fenced off during construction to <br />prevent soil compaction or damage to plants. <br />STEP 2: Inspect delivery tickets for compost, <br />topsoil and mulches. <br />Permitee must provide original delivery tickets for all soil <br />and mulch products. Compare delivery tickets with the <br />SMP to match the following information: <br />• Delivery location. <br />• Total quantities for each soil product and mulch. <br />• Product descriptions and sources. <br />If materials other than those listed in the SMP were <br />delivered, laboratory test results must be provided to <br />confirm that they are equivalent to approved products. <br />STEP 3: Verify depth of amended soil and <br />scarification. <br />Use a shovel to dig at least one test hole per acre for turf <br />and one per acre for planting beds to verify eight inch <br />topsoil depth (below mulch layer), incorporation of <br />amendments, and four inches of uncompacted subsoil. <br />MULCH <br />LOOSE SOIL " • �, <br />with visible dark • <br />organic matter <br />LOOSE OR <br />FRACTURED 1 <br />SUBSOIL <br />• � e <br />Test holes should be about one foot deep (after first <br />scraping away any mulch) and about one foot square. <br />Eight Inch Depth of Amended Soil. The top eight inches <br />of soil should be easy to dig using a garden spade driven <br />solely by your weight. The soil should be darker than the <br />unamended soil below, and particles of added organic <br />14 <br />