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water-bearing zones, including Colorado River alluvium (OW-11), <br />Alkali Creek alluvium (OW-2 and OW-3), colluvium, and upgradient • <br />colluvium/alluvium. Except for OW-11, all wells are either a <br />sodium sulfate or sodium bicarbonate sulfate water type. Several <br />of them are also high in calcium. OW-11 is clearly a sodium <br />chloride water. Total dissolved solids range from 900 to 1900 <br />mg/1. The TDS of the Colorado River alluvium at OW-11 (1900 mg/1) <br />is suspicious, particularly since it was taken from an abandoned <br />6-inch diameter well. An attempt was made to remove considerable <br />water prior to sampling, but concentration by evaporation may still <br />be a problem. However, the ratio of the constituents may not be <br />affected. Another explanation for this high TDS is that this area <br />is receiving underfloor of poor quality ground water which is mixing <br />with Colorado River alluvial water (Figures 3.3-6 and 5.1-1). The <br />well log for OW-11 suggests that the well was overdrilled into <br />bedrock, which is the Jurassic Morrison Formation at this location. <br />Discussions with the State Geological Survey revealed that springs <br />of low water quality issued from the Morrison Formation from within <br />Colorado Highway excavation adjacent to OW-11. <br />After plotting temperature versus time for each of the monitoring <br />sites, it was discovered that a change in thermometers between <br />November, 1982 and April, 1983 resulted in a 2.5 degree C decrease <br />in all temperatures measured during this time period. The plots <br />that are presented here have been corrected for this error, but the <br />data as recorded is presented in Appendix 3.3-10. <br />3.3.4.6 Recharge and Discharge <br />Bedrock <br />The direction of ground water movement in the bedrock water-bearing <br />units within the permit area is down-dip towards the Piceance <br />basin. This flow direction is consistent with the regional ground <br />water flow system. Ground water gradients have been measured at <br />other sites along this structural and stratigraphic sequence within • <br />NCSC - Coal ILidga #1 3-30 ABC/1145/9OO3O1 <br />