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Groundwater Sampling and Analysis Plan Sprayfield Groundwater Monitoring North Lathrop Specific Plan Lathrop, California This groundwater Sampling and Analysis Plan (SAP) outlines field procedures to be employed during the course of completing quarterly groundwater sampling at the North Lathrop Specific Plan,Lathrop California. Water Level Measurements • Prior to sampling, each monitoring well will be gauged using a depth to water meter. Depth to water will be measured from the top of casing of each monitoring well to determine groundwater elevation. Each monitoring well will be surveyed to a common datum prior to water level measurements. Depth-to-water indicators will be decontaminated and rinsed between well measurements. Well Purging • Prior to sample collection, each well will be purged of at least three well volumes using either a 12-volt DC or electric submersible purge pumps. • If the monitoring well goes dry prior to purging three volumes, the well will be left to recharge to determine if additional water is able to be purged. If three well volumes still cannot be purged after a given amount of time, a sample will be collected and the amount of water purged will be recorded in the field notes. • During purging of the wells pH,conductivity,temperature,and turbidity will be monitored and recorded to confirm stabilization. • A sample field sampling form is attached. Sample Collection and Handling • Purging will be conducted at a slow rate to prevent the cascading of water into the monitoring wells. Efforts will be made to prevent the wells from being pumped dry. • Samples will be collected using dedicated, disposable bailers. The bailers will be kept in plastic until such time as to be immediately used in the field. All bailers will be air dried and disposed of following use. • Samples will be collected and transferred into appropriate containers in a manner to minimize the volatilization of organics. Water will be transferred from bailers to sample containers at a trickle rate. Sample containers will be filled such that no headspace is present in the sample containers. • A sample label will be placed on each sample container that indicates the sample ID, date and time of collection and the sampler signature.