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o i\J A ~ CHAPTER IV PROBLEM IDENTIFICATION AND QUANTIFICATION ACTIVITIES <. apparently have had little effect on the upper Morrison aquifer, since hydraulic continuity had not been disrupted. Faults and/or closely spaced joints created localized zones that were more transmissive than others but, overall, the upper Morrison produced up to 100 gallons per minute (gpm) of saline water from the same geologic and stratigraphic position over most of the dome. On either flank of the dome, increased gradients and less over- burden allowed upper Morrison water to recharge the lower part of the Dakota Sandstone where saline water under pressure is found. The Dakota Sandstone contained water with quality nearly identical to that in the upper Morrison. Elsewhere on the dome, the Dakota was not saturated and therefore was not considered an aquifer. A largely unconfined alluvial aquifer on the eastern edge of the dome had been intruded by saltwater flowing from the Dakota Sandstone. No usable ground water resources existed in the dome area because saline water had penetrated all permeable zones within the upper 2,100 feet of sediments. Surface water quality The dissolved solids in the White River above Coal Creek were pre- dominantly calcium bicarbonate and calcium sulfate. Coal Creek water had a calcium, magnesium, sulfate, bicarbonate composition with over three times the total dissolved solids (TDS) concentration of the river. Curtis Creek was much more saline, but ita magnesium sulfate/sodium sulfate character indicated a different source of salt content--Mancos Shale which occurs throughout the watershed. The salinity of the river at Meeker was higher than at Coal Creek, and there were significantly higher sodium, chloride, and sulfate concentrations. These three con- stituents accounted for approximately 75 percent of the increase in TDS in the surface water. Ground watet quality When first penetrated by the Meeker and Marland Wells, the bedrock aquifers beneath Meeker Dome apparently contained water of different quality. Observations made at the drilling were largely based on easily perceived differences such as temperature and odor. Discharge from the Meeker Well was noted to have become more mineralized when the Marland Well was drilled. '. All bedrock aquifers contained saline water with very similar chem- ical makeup. The saline water in these aquifers contained an average of 17,520 mg/L TDS with the following ions present: chloride, 44 percent; sodium, 32 percent; and sulfate, 18 percent.l/ . There were temperature differences among the waters in the various bedrock units. Temperatures in the deep bedrock units encountered at l/ Percentages were based on weight (mg/L). 10.