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ExxonMobil Global Services Page 19 <br />Colony Shale Oil Project <br />ESR Reclamation Studies <br />Weighing Lysimeter Perfom~attce 1990-2003 <br />Project No. 353 <br />plant water demand. The water that passed through the topsoil zones cleazly increased the <br />moisture content in the combusted shale (red and grey traces on Fig 4.1, but it did not <br />percolate out. It either became hydration product (mineral bound water), or it filled the ESR <br />shale to that material's field capacity. Since mnieral bound hydration water would not be <br />observable to the TDRs, which sense the dielectric constattt that reflects only liquid water, the <br />increase in moisture in the ESR shale that is visible in Fig 4.1 is cleazly liquid, i.e. "drainable" <br />water. The moisture drops off in the summer, but there are no plant roots in this material, and <br />there was no percolate. It is therefore likely, given the available hydration capacity of the ESR <br />combusted shale which was placed at a relatively dry moisture content (25%), that much of <br />the initial increase in moisture in these fast few years was consumed in hydration, and never <br />percolated out of the system. This would explain the reductions in moistvre in the ESR <br />combusted shale (red and grey traces) in the absence of percolation in the years 1990 through <br />• 1992. It must also be remembered that the plots were exposed to infiltrating moisture in 1989 <br />before these measurements commenced, so some hydration capacity had already been <br />consumed by 1990. <br />Even with minimal plant cover, there is a regulaz seasonal weight loss of about 4,000 <br />lbs ( 4.3 inches over the I S ft diameter lysimeter) in the summer in 1990 and 1992. This is <br />not as large as the average summer weight loss of about 7,500 Ibs once the plants had <br />matured, but it does indicate that the "evaporation" component of evapotranspiration was in <br />play in the absence of a thick plant cover. <br />4.3.2 1993 <br />This is the first year in which percolation was observed. It appeazs the hydration <br />capacity of the limited thickness (~ 60"} of ESR combusted shale had been exhausted, and the <br />moisture content was close to field capacity. Any additional infiltration water that escaped the <br />root zone of the still immah,ra plants would cause drainage. It should be noted that to a full <br />C <br />LACHEL FELICE & Associates <br />