CORRESPONDENCE_2005-2011 - Laserfiche WebLink

Home Browse Search

01/03/2008 15:18 209835 5 Valley Organics, Inc. Green Waste Composting Facility, Lathrop, CA WORKPLAN FOR WELL RADIUS SEARCH AND GROUNDWATER SAMPLING 2098350675 PAGE 08 8112,000.000 December 4, 2007 Page 4 Alternatively, the San Joaquin Cotinty Environmental. Health Division (SJCEHD) maintains similar information on supply well installations that is more readily available. Therefore, ENGEO will contact SX131-11) to obtain information on permitted well installations within %-mile of the Site. Groundwater Samplin The procedures provided in the Workplan are solely for the sampling described in this section. Any changes, additions or deletions to the planned sampling location will be appropriately documented in our report of findings with the reasoning provided for the Workplan modifications. Two wells currently exist on the Site — one operable domestic well and one inoperable agricultural supply well (Figure 2). Based on field observations and the documented shallow depth to first -encountered groundwater, ENGEO expects that both wells are completed at similar depths. Due to the technical difficulty of producing groundwater froin the agricultural well and the relative likelihood that groundwater fxom each well would yield similar information on water quality, ENGEO will collect one groundwater from the domestic well, Based on field observations, ENGEO will obtain a groundwater sample froin the faucet tap at the well and holding tank. No filters exist prior to sampling port. The following is a summary of the field sampling procedures: • The volume of holding tank will be estimated. • Based on flow estimates measured by timing flow into a calibrated bucket, the purge volume of the holding tank will be evacuated prior to sampling. After the holding tank volume has been evacuated, water will be allowed to tun for an additional 1.5 minutes. • The conductivity, temperature, ply, and turbidity of the groundwater will be measured periodically in a separate container. All field measurements will be recorded on a sampling forin (attached) and in a field logbook. At least four measurements will be collected during the final 15 -minute purge cycle. In any event, the conductivity and pH measurements should stabilize within 10 percent prior to sample collection. • Using the calculated flow rate, the total volume purged will be recorded. • A water sample will be collected from the tap by filling the sample containers directly. • All sarnples will be placed on ice immediately ager collection. Preservatives will be recorded on sample labels and sampling forms. • Samples will be labeled and packed for transport following chain -of -custody record procedures.