ARCHIVED REPORTS XR0012673 - Laserfiche WebLink

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{ i Monitorine Weil Car ve[ Pack A ri d_5_1QL51Z0ShCLl Ent The size of the gravel pack that will be placed adjacent to the well screen will be determined by the project manager based on an estimation of the distribution of grain size in the formation which is likely to be encountered within the uppermost saturated zone at the site. Available geologic fs information will be utilized in the selection of this grain size. The gravel pack will be selected such that it will permit the development of a zone of higher hydraulic conductivity adjacent to the well .a screen but will not allow pipinL of the finer-grained formation into the well bore. The slot size of I the well screen will be selected such that it will retain a minimum of 9596 of the gravel pack material. 1.5 Monitorinp ell D r l m n if monitoring wells are installed, each monitoring well will be developed after construction with a E 1.75-inch diameter manual pump until the water produced is relatively sediment free or until measurements of pH, specific conductance, and temperature stabilize. If the well is pumped dry during the development process, recharge rates will be recorded. No water or chemicals will be a introduced into the monitoring wells during well development. All developed water will be placed in drums on-site for later disposal. � a 1.6 Groun? Water$amnling A minimum of 24 hours following well development, and after water levels have been allowed to t ` . stabilize in the well, three to five wetted casing volumes of liquid will be removed front each well -cleaned teflon bailer. Measurements of pH,specific conductance,and by bailing with alaboratory temperature will be made at regular intervals during this procedure. Removal of liquid from each .,, well will continue until the measurement pia,specific conductance,and temperature have stabilized. A liquid sample will then be collected from each well with a laboratory-cleaned, dedicated teflon bailer. Each sample will be appropriately labeled and stored an ice from the time of collection through the time of delivery to the laboratory. Ground water samples will be transported to the laboratory and analyzed within the EPA-specified holding times for the requested analyses. 1.7 PetroleuM-"r duc If free petroleum ;b.-Auct is present in a well,the thickness of the product layer will be measured by the"paste and tapir"method. This method will consist of coating a water level indicator tape with a water-finding paste and measuring the thickness of the product layer as indicated by the solar ^^ change of the paste. Position of the oil/water interface will be determined by subtracting the position of the interface as indicated by the color change from the depth indicated on the water level indicator tape adjacent to the top of the PVC casing when the measurement is made.