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I I I I . I . I . . . . I I I I I I I 000681 the Rowe Sanctuary site. The overall difference in mound heights due to a :hange in specific yield was small. The transmissivity calculated for the recharge basin location was 1710 'e/day. It was found as a combination of the soil permeability, K, of 22.5 fUday 3nd the thickness of the unconfined aquifer of 76 feet. As the aquifer thickness Nas an accurate value obtained from the U,S. Geological Survey, the focus of he transmissivity sensitivity analysis was with the influence of varying the )ermeability, K. Figures 11 a and 11 b illustrate the effect of a change in the )ermeability and therefore, the transmissivity on the mound height at the center )f the basin and at a distance of 300 feet. The analysis used a vertical plane of 30 degrees to eliminate the influence of the river. The thickness of the aquifer vas held constant at 76 feet. Sensitivity Analysis of Transmissivity Effect on Mound Hei9ht @ Center r- Sensitivity Analysis of Transmissivity Effect on Mound Height @ 300 n g 0.89 .! 0.88 8 = 0.87 . t 0.86 . .; 0.85 c ~ 0.84 ~ ~ n ~ M ~ Hydraulic Conductivity (ft/day) g ~2.4 . .. 023 I"--- lJ . ~ 2.2 " ~2.1 . ~ ~ 2 , II ~ ..... 21 n ~ 24 Hydraulic Conductivity (ft/day) 25 'igure 11a: Effect of Mound Height at Center Figure 11b: Effect of Mound Ht at 300 ft -he mound height both at the center of the basin and at a distance of 300 ft lecreased as the soil permeability or hydraulic conductivity was increased over he maximum range of values for the Rowe Sanctuary site. The overall Iifference in mound heights due to a change in permeability was small. 4.5.5 Calculation of Return Flows to The Platte River An analysis of the return flow to the Platte River for the 20 day recharge .eriod and the 15 day recession period was performed for the recharge basin lesign at the Rowe Sanctuary site. The amount of return flow to the Platte River 23