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Mr. Geoff Rader, RWQCB Work Plan for Offsite Monitoring Well Installation 1120 West Hammer Lane, Stockton, CA Page 3 August 28, 2017 Project No. 2129-1140-01 The initial 5 feet of the boring will be advanced with a hand auger and/or posthole digger to reduce the possibility of damaging underground utilities. Soil samples will be collected in 5-foot intervals during the advancement of the well boring using a California-type, split-spoon sampler equipped with three pre-cleaned brass or stainless-steel sleeves. The ends of the bottom-most, intact sleeve from each sample interval will be lined with TeflonTm sheets, capped, and sealed. Each sample will then be labeled, placed in a resealable plastic bag, and stored in an ice-chilled cooler. Strict chain-of-custody procedures will be followed from the time the samples are collected until the time the samples are relinquished to the laboratory. Additional soil recovered during sampling will be screened for volatile organic compounds wing a photoionization detector (PID). Stratus will record PID readings, soil types, and other pertinent geologic data on a borehole log. Stratus will select the number of soil samples for chemical analyses at the time of the investigation, based on the soil types encountered and field findings during this work. Tentatively, Stratus anticipates submitting soil samples collected from approximately 30, 40, and 50 feet bgs for chemical analysis, unless field observations dictate another course of action. Task 2B: Groundwater Monitoring Well Installation S UILIM 1.jj Groundwater monitoring well MW-13 will be constructed using 2-inch diameter P casing and 20 feet of 0.02-inch factory slotted well screen, extending from approximately 30 to 50 feet bgs. A filter pack of #3 sand will be placed in the annular space around the well from the bottom of the well screen to approximately 2 feet above the top of the well screen. Approximately three feet of bentonite chips will be placed on top of the filter pack and hydrated with clean water to provide a transition seal for the well. Neat cement will be used to backfill the remaining annular space around the well casing up to surface grade. The actual well construction may be modified in the field based on conditions encountered at the time of the investigation. Task 2C: Well Development and Sampling Newly installed groundwater monitoring well MW-13 will be allowed to stand a minimum of 72 hours before development. This well will be developed by surging with a bailer, followed by groundwater pumping. Development will continue, to the extent practical, until the development water runs clear and pH and conductivity measurements stabilize. Approximately 10 well casing volumes will be removed during development. After well development and stabilization of the water levels, water levels and the quantity of well volumes removed from the well will be recorded. K:\Knowles-Hanuner LaneWork Plans\knowles-hammer-offsite-well-workplan.doc STRATUS