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August 18, 2014 <br /> Gibson Bluff <br /> L&A Job No. 14-056 <br /> Page 20 <br /> LIST OF SOIL SAMPLES <br /> Sample Test Depth Soil <br /> No. Boring No. feet Description <br /> 1 B-1 5.0 - 6.5 Dark olive-brown,poorly-graded SAND with silt and gravel <br /> 2 B-2 10.0- 11.5 Dark olive-brown, well-graded SAND with silt and gravel <br /> 3 B-3 10.0- 11.5 Dark olive-brown,poorly-graded SAND with silt <br /> The percentages of clay, silt, and sand/gravel of the soil samples determined from the <br /> particle size distribution tests are summarized on Plate A-2. Based on these percentages <br /> the soil samples were classified according to the USDA (U.S. Department of Agriculture) <br /> Texture Triangle chart, a copy of which is shown on Plate A-3 in the attached Appendix. <br /> The classifications of soil samples are presented in the table below. <br /> USDA TEXTURE TRIANGLE CLASSIFICATION OF SOIL SAMPLES <br /> Sample Percentage Percentage Percentage USDA Texture <br /> No. Clay Silt Sand/Gravel Triangle Classification <br /> 1 2.0 3.4 94.6 Sand <br /> 2 2.1 5.2 92.7 Sand <br /> 3 1.8 4.5 93.7 Sand <br /> Volume III, Section 3.3.6, Article 3 - Soil Grain Size Analysis Method, of the Stormwater <br /> Management Manual for Western Washington, 2012 Edition, published by Washington <br /> State Department of Ecology, is used to determine estimated design infiltration rates of <br /> the target soil deposits. This method uses D10 , D60, D90 and fomes in calculating the <br /> saturated infiltration rate (conductivity), Ksat in cm/sec; where D10 , D60, D90 are the sizes <br /> LIU & ASSOCIATES, INC. <br />