ARCHIVED REPORTS_XR0003248 - Laserfiche WebLink

Home Browse Search

City of Stockton - Van Buskirk Park Golf Course TL 39¢0074-01 July 29, 1994 Page A-4 A-5 Standard Operating Procedures for Measuring Depths to Water and Calculating Groundwater Elevations Monitoring well locations and top-of-casing elevations are surveyed by a California-licensed land surveyor. Surveyed data is referenced to a local benchmark, an assumed local datum, or a United States Geological Survey benchmark. The surveyed data is accurate to ±0.01 feet. ' Depth to groundwater is measured relative to a surveyed point on the north edge of the well casing rim. The water depths are measured using an electronic water sensing meter with ' a precision accuracy of± 0.01 feet. The depth to water in each well at a site is measured in a single day. Measurements are recorded on the daily field log. If floating hydrocarbons are suspected, a bottom-filling clear bailer or hydrocarbon detecting paste bailer may be used to record floating hydrocarbon thickness. The bailer is lowered ' to a point just below the liquid level, retrieved, and observed for floating hydrocarbon. Groundwater elevations are calculated by subtracting measured water depths from surveyed casing rim (measuring point) elevations. The direction of groundwater flow and gradient may be calculated using the groundwater elevation data. A-6 Standard Operating Procedures for Performing Head Space Analysis Head space analysis is performed using a photoionization detector (PID) or a drager tube. ' A soil sample is placed in a sealed glass container or plastic bag, agitated, and placed in a warm atmosphere. After approximately 15 minutes, which is generally sufficient for some of the volatiles to escape from the soil, the PID probe or tip of the drager tube is inserted into the container and the gas is sampled. The highest concentration of organic vapors recorded by the PID or the drager tube reading will be recorded. ' A-7 Standard Operating Procedures for Laboratory Quality Assurance/Quality Control These laboratory QA/QC procedures were developed to reduce outside interferences during ' analyses of samples. The laboratory director is responsible for creating and maintaining the program. General QA/QC procedures follow: ' a Analytical instruments are serviced,on a regular basis to assure accurate calibration; a Organic-free water is monitored daily for quality; ' a Gas chromatographs are calibrated daily; a Method blanks are run to check whether the glassware and reagents are free of interference from chemicals that would invalidate the analyses;