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• <br />ExxonMobil Global Services <br />Colony Shale Oil Project <br />ESR Reclamation Studies <br />Weighing Lysimeter Performance 1990-2003 <br />Project No. 353 <br />Page 13 <br />4.0 ANALYSISAND CONCLUSIONS <br />4.1 Overview of Water Balance Findings <br />The data collected from years 1990 through year end 2003 are summarized presented on <br />• <br />Figure 4.1. This chart presents the apparent moisture changes at various depths in the lysimeter, the <br />annual rainfall, changes in the lysimeter's weight, and measured runoff and percolate quantities. A <br />variation of this is presented as Figure 4.1-a where the moisture content in the ESR combusted shale <br />are highlighted with a trend line. There are a number of observations evident on these plots that <br />correlate to the evapotranspiration models. These will be discussed in Section 4.2. <br />A summary of the fate of precipitation, split between evapo-transpiration, runoff, change in <br />storage, and deep percolation is presented in Fig. 4.2. Annual values as well as 14 year averages are <br />presented. It is worth noting that averaged over the 14 years, percolation, storage, and runoff each <br />account for only a few percentage points of the annual precipitation. Specifically, the averages for <br />runoff, storage, and deep percolation are respecfively 4.3%, 3.8% and 2.9%. Conversely, evapo- <br />transpiration, asmeasured by actual water balance in the weighing lysimeter, accounts for an average <br />of 89% of the annual precipitation. This reinforces the difficulty of determining deep percolation <br />losses by differences using only estimated values of evapo-transpiration. For example, a 10 % error in <br />the modeled evapo-transpiration amount, which would be considered a very accurate modeling effort, <br />is as large as runoff, storage and percolation combined, and is three times the value of the percolation <br />value that is being sought by infiltration models. A weighing lysimeter is therefore essential if reliable <br />inferences regarding potential infiltration into a commercial spent shale pile are required for design. <br />Figure 4.3 presents the Jensen-Haile summary averaged over the 14 years. Here the month to <br /> <br />month water balance can be inferred. Although individual year's tables and plots are presented in <br />LACHEL FELICE & Associates <br />