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EXHIBIT I (Cont'd) <br />feet to 5 feet. The SCS reports the soil usually extends to <br />a depth of about 60 inches, but such was not generally found to <br />be the case here. In general, it can be assumed safely that <br />on the average about 12 inches of soil would be suitable for <br />salvage as topsoil. Below that level, salinity and alkalin- <br />ity may increase because leaching probably transported the <br />chemicals to lower levels. <br />Heldt clay loam, 1 to 3 percent slopes (map unit 38B) - <br />This soil is quite different from the Wann sandy loam. The <br />clay content is much higher and this produces a high shrink- <br />swell potential. This potential can create large polygonal <br />blocks separated by large cracks when the soil dries. Its <br />surface layer is about 8 inches deep and is a clay loam texture. <br />Below that is usually found about a foot of clay loam. The <br />second horizon is a bit lighter in color than the surface <br />layer. Below about 20 inches the soil becomes a gray clay <br />that is very heavy. <br />On this site cracking was not observed. This may be due to <br />the long-term cultivation of the soil and the consequent incor- <br />poration of organic matter which can reduce the shrink-swell <br />potential. It could also be that at the time the survey was <br />conducted, the soil was not dry enough to produce cracking. <br />Percolation rates are quite slow and water-holding capacity <br />is moderate. The native vegetation probably would have been <br />a mixture of sagebrush, rabbitbrush, and wheatgrass with little <br />if any saltgrass or other halaphytes <br />On the site though, <br />-31- <br />