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*'East Area" refers to those areas where Lift A Topsoil or Mixed Lift Topsoil is placed directly on the Bench 1 <br />Subsoil Substitute (no Lift B Topsoil is present) <br />a "Remaining Area" refers to those areas where both Lift B Topsoil and Lift A Topsoil or Mixed Topsoil are <br />replaced over Bench 1 "Spoil" <br />Zones 1 & 2 - areas where Lift A Topsoil or Mixed Topsoi is placed directly on Bench 1 Subsoil Substitute (no Lift <br />B Topsoil is present) <br />Zones 3 & 4 - areas where both Lift B Topsoil and Lift A Topsoil or Mixed Topsoil are replaced over Bench 1 <br />Surface Spoil <br />'The actual maximum acceptable salt level, measured by Electrical Conductivity, will depend on the plant species <br />proposed in the revegetation plan and the potential for upward salt movement. As pointed out in the report in <br />Attachment 2.05.4(2)(d) -1, NRCS stated a level of 6.0 in the subsoil would not be detrimental to grasses or alfalfa. <br />A study done by Curtis Swift, PhD. of Colorado State University (Attachment 2.05.4(2)(d) -2), titled Salt Tolerance <br />of Various Temperate Zone Ornamental Plants, shows that alfalfa handles a soil conductivitiy of 4- 8mmho /cm. <br />The specific species cited is Medicago Sativa, which is the same as that prescribed in the revegetation plan for <br />Irrigated Cropland. Also this reference does not differentitate between topsoil and subsoil. Based on this data, <br />and NRCS recommendations, the limits for Electrical Conductivity are shown in Table 2.05.4(2)(d) -1A and 1 B for <br />the various topsoil and subsoil types. The averages will be reported for each landowner in the Soil Sampling <br />Report. <br />2 USDA Soil Textures - unsuitable textures area: S -sand, LS -loamy sand, SC -Sandy clay: SIC -Silty clay, C -Clay <br />3 The 3- inch -plus % is estimated visually (by volume) by sweeping the face of the area being inspected, measuring <br />out the area's depth, and then estimating boulders, cobbles, and stones using USDA criteria. The 3- inch -minus <br />rock fragment volume is estimated using sieve and collection pans. This is done by taking the thickness sample of <br />the material, placing it in a graduated sieve with a 2 mm final sieve size, and sieving the soil to the bottom of the <br />sieve pan. The volume of soil remaining in the 2 mm and larger sieves is then estimated for the 3- inch -minus rock <br />fragment. These two component measurements are then summed to give the Rock Fragments value- <br />4 pH values in the table represent the acceptable range that sample pH must fall between. <br />Revised September 2010 (PR 06) 2.05.4(2)(d) -6 <br />