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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />. <br />I <br />I <br />I <br />I <br />I <br />. <br />I <br />I <br />I <br />I <br /> <br />000580 <br /> <br />All three plots showed a steady reduction in the peak height of the mound as the <br />time after recharge was increased. The influence of the Platte River again was <br />evident in Figure 9a at a distance of 900 feet. The height of the groundwater <br />mound remained greater than 0.5 feet after 15 days at a distance of 300 feet for <br />all three comparisons. The residual effects of the recharge operation were <br />significant which would allow the wet meadow vegetation to benefit long after the <br />recharge operation was completed, <br />4.5.4 Sensitivity Analysis of Transmissivity and Specific Yield <br />The two primary model parameters that are dependent on the natural soil <br />characteristics of the recharge location are the transmissivity and the specific <br />yield. Both parameters will vary with the soil type found at a given recharge site. <br />An understanding of the sensitivity of the CSUPAW model to changes or <br />inaccuracies with these parameters is beneficial. <br />The specific yield was originally determined by averaging the values for <br />specific yield given for each type of soil found at the Rowe Sanctuary site. The <br />possible range of values for the specific yield was from 0.23 to 0.28. Figures <br />10a and 10b illustrate the effect of a change in the specific yield on the mound <br />height at the center of the basin and at a distance of 300 feet. The analysis <br />used a vertical plane of 90 degrees to eliminate the influence of the river. <br /> <br />Sensitivity of SpeCific Yield <br />_ Effect on Mound Height @ Center <br />!0- <br />j 2.25 .......... <br /> <br />~ 2.2 <br />. <br />" <br />~ 2.15 <br />. <br />~ 2.1 <br />.. <br />'" <br />'g 2.05 <br />~ 0.23 0.24 0.25 0.26 0.27 <br />Specific Yield <br /> <br />0.28 <br /> <br />Sensitivity of Specific Yield <br />Effect on Mound Height @ 300 ft <br /> <br />gO.94 <br />jO.92 <br />~ 0.9 <br />1; 0.88 <br />iO.B6 <br />! 0.84 <br />'g 0.82 <br />i 0.8 <br />0.23 0.24 0.25 0.26 0.27 <br />Specific Yield <br /> <br />0.28 <br /> <br />..... <br /> <br />Figure 10a: Effect on Mound Height at Center Figure 10b: Effect of Mound Ht at 300 ft <br /> <br />The mound height both at the center of the basin and at a distance of 300 ft <br />decreased as the specific yield increased over the maximum range of values for <br /> <br />22 <br />