ARCHIVED REPORTS XR0010404 - Laserfiche WebLink

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- - --- - - of medium to coarse sand. From approximately 15 to 18 feet dark PP Y gray coarse sand, contains pebbles to 1/4 inch in size. From approximately 18 to 21 feet, medium-brown silty clay, moist scattered caliche. This well was very quick to charge. At :1 approximately 20 feet the boring was terminated. Ten feet of 0.02 inch screened 2-inch-diameter, Schedule 40 PVC i casing was placed at the bottom of well MW-2. The remainder of the well was constructed using regular 2-inch-diameter, Schedule 40 PVC casing. Approximately 12 feet of #3 Lonestar Sand was : j used for the filter pack with a two foot Bentonite seal above the sand. The remaining portion of the well was filled with cement grout and a stove pipe placed above grade to avoid surface water contamination. A locking cap with lock was placed in the casing to avoid inadvertent surface contamination to groundwater. For Boring MW-BTI , the first .9 feet was fill . The next foot was dark gay clay moist and plastic. From approximately 10 to 13 feet, tan silty clay, moist, moderately plastic, some caliche. From 13 to 15 feet flowing sand. From approximately 15 to 20 feet, fine to medium grain sand, little to no fines, moist. From 20 to 23 feet coarse sand, wet. The next foot rounded to subrounded gravel in a coarse sand matrix, sandstone and chert with quartz veins. From approximately 23 to 24 feet medium-brown silty clay to clayey silt, wet, moderately plastic. This well was very quick to charge. At approximately 24 feet the boring was terminated. i4 Thirteen feet of 0.02 inch screened 2-inch-diameter, Schedule 40 PVC casing was placed at the bottom of well MW-2. The remainder of the well was constructed using regular 2-inch-diameter, Schedule 40 PVC casing. Approximately 15 feet of #3 Lonestar { Sand was used for the filter pack with a two foot Bentonite seal above the sand. The remaining portion of the well was filled with cement grout and a stove pipe placed above grade to avoid surface water contamination. A locking cap with lock was placed in the casing to avoid inadvertent surface contamination to groundwater. g Well and boring logs as well as OVM data are contained in Appendix A. Gradient Calculation Prior to purging and sampling the depth to groundwater was measured by an electronic probe in the four Monitoring Wells on site. The water depth was measured from a mark located on the top of the casings. An assumed elevation of 50.00 feet was assigned, based on the USGS Quad for the subject area, to the concrete pad of the building nearest Eleventh Street. The well casings were surveyed with respect to the arbitrary benchmark of 50.00 feet on the concrete pad. The groundwater gradient data 4