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0 0 <br /> Musco Family Olive Company - 2 - 5 October 2017 <br /> the first encountered water. MW-36 was screened from 133 to 143 feet bgs using a 2/16 <br /> sand for the gravel pack. Initial water levels indicate a static level at 146.50 feet MSL <br /> compared to MW-35R, installed 100 feet east of MW-36, which shows a water level at <br /> 146.64 MSL. <br /> • Piezometer PZ-1 was installed north of MW-36 and MW-35R to provide triangulation of the <br /> shallow water bearing zone. PZ-1 was drilled using hollow stem auger drilling methods and <br /> the first encountered water was identified at 123 feet bgs with the water bearing zone <br /> extending to 127 feet bgs. A confining layer was identified below 127 feet bgs and the boring <br /> was terminated at 145 feet bgs. PZ-1 was constructed with a screen from 120 to 130 feet <br /> bgs. Initial water levels indicate a static water level at 149 feet MSL. Future monitoring will <br /> be used to determine whether the piezometer is completed in the same shallow zone as <br /> MW-36 and MW-35R. <br /> • Lysimeter 36R was installed at 25 feet bgs, which is approximately seven feet below the <br /> liner system for Surface Impoundment B, or approximately 249 feet MSL. Groundwater was <br /> not encountered in the borehole, and the lysimeter was seated in the borehole with <br /> approximately 12 inches of silica flour slurry. Bentonite and cement grout was used to seal <br /> the annular space from 24 feet bgs to the surface. <br /> In staff's 29 August 2016 letter, and again in our 4 April 2017 conditional Work Plan approval <br /> letter, we requested Musco to deepen currently dry monitoring wells MW-12 and MW-17. <br /> Terraphase responded that MW-12 and MW-17 are side gradient to Surface Impoundment B <br /> and deepening these wells may not provide any added value to the groundwater network. <br /> Additionally, Musco and their counsel pointed out that WDR R5-2014-0125 includes a <br /> discussion of MW-12 and MW-17 in the Findings, but not in the Hereby Ordered section; <br /> therefore, Musco decided not to complete this work at this time. Terraphase concluded in the <br /> I&E Report that the current monitoring points located adjacent to Surface Impoundment B can <br /> provide the earliest indication of a release, and that a monitoring point at MW-12 and MW-17 <br /> locations are not necessary at this time. <br /> Terraphase provides an evaluation and certification in the I&E Report that all geologic <br /> information, conclusions, and recommendations have been prepared by Andrew Romolo, <br /> California Professional Geologist No. 8110, and that that the groundwater monitoring network is <br /> in compliance with Title 27 Requirements. Based on the well installation work completed as <br /> described in the i&E Report, staff finds that Musco met the intent of the Work Plan as <br /> conditionally approved by staff on 4 April 2017. Musco is directed to continue to evaluate the <br /> groundwater detection monitoring networks through groundwater monitoring and sampling, and <br /> to provide an update of the hydraulic connectivity of the shallow and deep well networks in the <br /> 2017 Annual Report. <br /> If you have questions regarding this approval letter, please contact me at (916) 464-4630 or at <br /> Marty.Hartzell@waterboards.ca.gov. <br /> MARTY HARTZELL, P.G., CHG <br /> Senior Engineering Geologist <br /> Title 27 Permitting and Mines Unit <br /> cc: Robert.McClullen, San Joaquin County Environmental Health, Stockton <br /> Howard Hold, Central Valley Water Board, Rancho Cordova <br />