Laserfiche WebLink
Metadata
Document management portal powered by Laserfiche WebLink 9 © 1998-2015 Laserfiche. All rights reserved.
California Department of Transportation June 7 1999 <br /> p sporta o , <br /> Shop 10 Maintenance Station, Stockton, California Project No 103872-02 <br /> 4. GROUNDWATER MONITORING ACTIVITIES <br /> 4.1. Groundwater elevation and hydraulic gradient <br /> Between March 29 and April 1, 1999, two representatives from Ninyo & Moore measured <br /> depth to static groundwater in the fourteen on-site groundwater monitoring wells Static <br /> groundwater levels were measured using a Heron air/water interface probe The probe was <br /> Idecontaminated prior to each use A summary of the current and previous depth-to- <br /> groundwater measurements is presented in Table 1 The depth to groundwater has risen in <br />' the on-site wells since the last monitoring event in December 1998 Based on groundwater <br /> data collected, the inferred direction of groundwater flow beneath the site is to the southeast <br /> 1 with a hydraulic gradient of 0 0026 feet per foot <br /> 4.2. Groundwater Sampling and Observations <br /> Using a 3-inch submersible pump, a minimum of three well casing volumes of groundwater <br /> were purged from each of the fourteen on-site wells prior to the collection of water samples <br /> The wells were allowed to recover to at least 80 percent of their original static groundwater <br /> levels prior to sampling During well purging, temperature, pH, and conductivity were <br /> measured using a factory calibrated Hydac instrument Additionally, characteristics of the <br /> water (color, turbidity, odor, sheen) were noted on the field data sheets included in Appendix <br /> A <br /> Subsequent to purging, samples were collected using disposable PVC bottom-discharging <br /> bailers The samples were transferred from the bailer to the appropriate sample containers, <br /> labeled, and placed in a cooler containing ice at 4 degrees Celsius under chain-of-custody <br /> protocol The samples were secured in a cooler and transferred to the Ninyo & Moore office <br /> in Oakland, California and temporarily stored in refrigeration California Overnight Service <br /> transported the samples to Applied Analytical Laboratory (AAL) in Orange, California <br /> Purged and decontamination water generated during sampling activities were transferred <br /> into labeled, reconditioned 55-gallon drums The drums were left on-site to be maintained <br /> by Caltrans <br /> ehopl0 3 &(��JU®ml7 �n <br />