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TRACY WWTo-TASK 14 TOS MOWTORIRO WELL INSTALLATION WORK GLEN • The surface seal will be concrete emplaced from the top of the cement grout to approximately 6 inches above grade. The surface seal will be graded from the protective casing to grade level for drainage. The well identifier will be marked in the concrete pad (and on the well cap). • A cylindrical steel,lockable protective casing will be emplaced into the surface seal. Two or three guard posts will be installed,if determined by the City to be necessary for protection from truck traffic. Specific details on final monitoring well design will be provided in the Monitoring Well Installation Report to be completed and submitted to the CVRWQCB after field activities are completed. Well Development Approach Installed monitoring wells will not be developed until at least 48 hours after installation to allow for grout curing.Wells will be developed using surge blocks along the entire well screen length and bailers or pumps.Development will continue until the measurements of temperature,conductivity,and pH are stable and the turbidity remains within 10 nephelometric turbidity unit(NTU)range for at least 30 minutes and no suspended turbidity or sediments are visible in the purge water.Purge water will be contained and then processed at the WWTP. Record of well development activity and monitored parameters will be maintained on the field activities form. Well Surveying A survey will be conducted after the completion of the field investigation using CH2M HILL licensed surveyors or a subcontracted licensed surveyor. The survey will be conducted to provide horizontal and vertical positions for sample locations.'The horizontal datum will be the California Coordinate System,North American Datum of 1983(NAD83), Zone 2;and the vertical datum used will be the North American Vertical Datum of 1988. The three new monitoring wells installed for this project will be surveyed,as well as the existing holding pond monitoring wells. This will enable comparison of water level data among the City's monitoring well network and groundwater investigations at other sites. For each well,the ground surface elevation at the northern edge of the pad will be surveyed. The measuring point on the well riser(also on the north side of the well)will be marked and surveyed. Schedule The new monitoring wells are planned to be installed either the week of November 19 or 26,2007. This enables the wells to be developed and then sampled in early December 2007 with the holding pond wells. Octobw 31.2007 7