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Mr. Douglas P. O'Neal, D10- Page Two Ms. Polly Lowry, CRWQCB Piezometers The proposed piezometers will be installed approximately 10 feet from well KI-5 to depths of 90 feet bls, 108 feet bls, and 133 feet bls. It is intended that the piezometers be completed in: the bottom of the shallow zone; the upper intermediate zone sand; and the sand lens in which lower intermediate wells KI-11, KI-13, and KI-14 are completed. The proposed piezometers will be constructed of 2 inch internal diameter PVC casing with five feet of slotted casing. The slotted openings will be 0.020 inches. The piezometers will be installed in 6-inch diameter boreholes drilled using conventional mud rotary methods. A filter pack of No. 2 sand will be placed in the annulus between the slotted casing and the borehole wall from the total depth of the borehole to approximately one foot above the top of the slotted portion of the casing. A layer of 1/4 inch bentonite pellets will be placed on top of the filter pack after airlift development of the piezometer. The remainder of the annulus will be filled with a bentonite grout such as Benseal (Figure 3). All wells and piezometers will be surveyed so that water level measurements can be referenced to a mean sea level datum. Testing Following construction each of the additional extraction wells will be tested individually to determine the transmissivity of the aquifer at those locations. The other additional extraction well, the piezometers, and well KI-5 will serve as observation wells during these tests. After these individual aquifer tests, the entire remedial well field will be pumped for a period of approximately three days to provide another set of drawdown data with which to calibrate the groundwater model. It is expected that the addition of the two extraction wells will stress the aquifer to a greater extent than was previously possible. A continuous water level recording device will be placed in well Kl- 14 for a period of three weeks before, during, and after the pumping of the remedial well field in order to identify potential regional changes in water levels that might affect the interpretation of test results. If you have any questions or require further discussion, please contact me. Very truly yours, Du & Associate , Inc. Irl Lv✓ Peter T. Quinlan, Project Manager Hydrogeology/flazardous Waste Division Enclosures cc: J. Tierney, Kearney-National J. Moss, Kearney KPF D. Peterson