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{( (( ll. (,'.] ~ r-- 16 ;:-:.:.-. r..., ~. ~-' ..... ._~ 6.2 Ground Water Conditions at the Contour Pond Site During the drilling program at the site, no measurable amounts of ground water were encountered during auger drilling in the surficial soils and weathered bedrock. Bedrock was cored using water as a drilling fluid and detection of flow into the holes during drilling was not observed. This does not preclude the presence of ground water, only that it was not present in sufficient quantities to be noticeable during drilling. Following drilling operations at each location, a 2 inch diameter PVC pipe (with the bottom 5 feet slotted) was placed in each hole and backfilled with clean sand. The-~pper_foot of the hole was backfilled with surficial soils and soils at the ground surface were mounded and sloped away from the hole to prevent surface infiltration. Borehole C-18 which was cored to 150 feet was doubly completed as shown on Figure 7. With the holes completed, the depth to water in each hole resulting from either infiltration of drilling fluids or ground water was monitored. The depth to water in each hole as last measured by the USBR is provided in Table 6-1. Based on this data, it appears that holes adjacent to stockponds and the major western drainage are consistently reporting water. The history of the water depths is shown in Table C-l of Appendix C. These indicate- that it is likely that ground water exists at borings C-2 and C-13 and fluctuates based on water levels in nearby stockponds. Due to the short period of monitoring, it is still uncertain whether water in holes C-6, C-14, C-15, C-16, and C-18A are a result of drill water or a shallow ground water system. It is likely if ground water does exist that it is an alluvial system since Lohman (1965) reports the Mancos shale is not water bearing in the Grand Junction area and only a very few wells have produced water from the Mancos shale. These wells are generally recognized to be from the weathered zone or from alluvium filling ancient arroyos or from both. In all instances, the water in the Mancos is generally of poor quality and unable to sustain much production.