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assumed to weather in response to the same conditions that would affect a prescriptive <br /> cover, the soil characteristics in the two model scenarios are the same. As a result, the <br /> most significant difference between the two models is the root distribution which is <br /> limited to the one-foot vegetative layer in the prescriptive case but extends to a three feet <br /> in the alternative case. <br /> 4.4.1.1 SOIL MOISTURE RESULTS <br /> Figure 2 depicts the modeled moisture content of the modeled degraded <br /> prescriptive final cover soils in percent by weight for six distinct depth intervals <br /> over a period of approximately ten years. As can be seen, in all cases for the <br /> constant potential boundary condition the shallow layers (3-inch, 9-inch, 15-inch <br /> and 21-inch)mimic seasonal precipitation patterns throughout the modeling <br /> period, while the deeper soil layers reflect only severe precipitation events. <br /> 4.4.1.2INFILTRATION <br /> Figure 3 depicts the calculated net flux through the layers of the modeled <br /> prescriptive final cover profile for the constant potential bottom boundary <br /> condition. As shown therein, infiltration potential for the prescriptive final cover <br /> is estimated to be about -0.69 inches/year. This value represents the performance <br /> for a degraded clay prescriptive final cover over the FSL. <br /> 4.4.2 ALTERNATIVE FINAL COVER <br /> As summarized above, the FSL non-prescriptive cover was modeled as a four foot thick <br /> (1219-mm)alternative cover composed of compacted on-site borrow soils combined with <br /> shallow to intermediate rooting native vegetation. The results of the modeling performed <br /> for this study are presented in Figures 4 and 5. <br /> 4.4.2.1 SOIL MOISTURE RESULTS <br /> Figure 4 depicts the modeled moisture content of the alternative final cover soils <br /> in percent by weight for several distinct depth intervals over a period of <br /> approximately ten years. Figure 4 represents the moisture conditions anticipated <br /> under the constant potential bottom boundary and also summarizes the rainfall <br /> history recorded at the Western Regional Climate Center's Stockton Station. As <br /> can be seen, the soil layers mimic seasonal precipitation patterns throughout the <br /> modeling period, though only the larger events penetrate to the deeper soil layers. <br /> 4.4.2.2 INFILTRATION <br /> Figure 5 depicts the net flux through the layers of the modeled alternative final <br /> cover profile under a constant potential bottom boundary condition. As shown, a <br /> negative flux potential of about—12.60 inches/year is calculated. 0 <br /> -10- <br /> C:\20050082\FORWARD/ForwardCOVER.DOC\7/1 J/2005 <br /> Geologic Associates <br />