ARCHIVED REPORTS XR0009939 - Laserfiche WebLink

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t"AMAErVNM Working to Restore Nature The wellheads were secured in cast-aluminum utilityboxes with PVC aprons The boxes P have watertight seals and were set in concrete approximately flush with the surrounding ground surface to reduce surface-water infiltration A special wrench is required to open the box This design discourages vandalism and reduces the possibility of accidental disturbance to the well Each wellhead was also fitted with a locking well cage to further protect against unauthorized disturbance of the well groundwater Monitoring Well Development Before developing the wells, static water levels were measured using a Solinst water-level meter Following initial water-levels measurements, the water in the wells were examined for subjective evidence of hydrocarbons by lowering about half the length of a Teflon bailer past the air-water interface The sample is retrieved and inspected for floating product, sheen, emulsion, color, and clarity The thickness of floating product detected was recorded to the nearest 1/8-inch Monitoring wells that did not contain floating product were developed using a 4-inch-diameter PVC surge block alternately raised and lowered through the water column in each well Development is performed to remove the fine-grained sediment from the monitoring well Subjective Analysis of Groundwater Samples iGroundwater samples were collected for subjective analysis from just below the air-fluid interface in a morutoring well by lowering approximately half the length of a clean Teflon bailer through the interface. The bailer was retrieved and the water sample examined for floating product, sheen, or other subjective evidence of hydrocarbons. Depth to Groundwater Measurements The depth of the groundwater surface in a monitoring well was measured from the top of the well casing to the nearest 0 01 foot with a Solinst or similar electric water-level indicator The well was be vented to the atmosphere before obtaining depth-to-water measurements Venting was conducted to allow the groundwater to equilibrate to barometric pressure These measurements were combined to evaluate the elevation of the groundwater surface in each well and the slope of the groundwater surface across the site. Groundwater Sampling The static water level in each well was measured to the nearest 0 01-foot with a Solinst water-level sounder cleaned with industrial soap and water before use in each well. A clean bailer was used to obtain a sample from the surface of the water in each well The sample was retrieved and inspected for floating product, sheen, emulsion, color, and clarity The thickness of floating product detected was recorded to the nearest 1/8-inch W3-7