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required if fine-grained soil is encountered to depths which are significant for excavation <br /> stability purposes. <br /> Mr. Terry Colvin <br /> May 5, 2006 <br /> Page 2 <br /> Groundwater levels are proposed to be determined during drilling, assuming that the <br /> potentiometric surface is encountered while drilling with hollow-stem augers. If it is required to <br /> switch to mud-rotary drilling prior to reaching groundwater, it will be more difficult or <br /> impossible to determine the elevation of the water in the borings during drilling. A 1-inch PVC <br /> piezometer will be installed in the deeper of the two holes to determine water levels at a layer <br /> date. <br /> In addition to obtaining water levels, it may be possible to develop an estimate of the <br /> transmissivity of the subsurface materials if a slug test is conducted using the piezometer. This <br /> would then allow a better understanding of the volumes of groundwater expected to require <br /> pumping during construction of the vault. However, this item would be in addition to the work <br /> proposed here. <br /> Per Geotech Explorations (the drilling subcontractor), the first date a suitable rig is available is <br /> May 15, 2006. The reporting, consisting mainly of drill logs is expected to be completed by the <br /> end of that week (May 19, 2006). <br /> GeoScience appreciates the opportunity to present this proposal. If you have any questions, <br /> please do not hesitate to contact me at (541) 607-5700. <br /> Sincerely, <br /> GeoScience, Inc. <br /> Gunnar Schlieder, Ph.D., CEG <br /> President <br /> <br /> err <br /> <br />