ARCHIVED REPORTS XR0009904 - Laserfiche WebLink

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' Corrective Action Plan Page 19 property as is found necessary to extend beyond, or approach as close as possible to, the linuts of the area affected by components of gasoline The maximum permissible slope of the walls of the pit will be determined by the geotechnical engineer in responsible charge of the work based on observations of soil stability made in the field However, it can be assumed that, in general, the side slopes of the pit will not be steeper than 1 5 ft to 1 ft vertical to horizontal except that, to achieve the maximum practical removal of contaminated soil from the subsurface, it is expected that it will be desirable for the sides of the excavation to approach as close as possible to the sidewalks on the East 11th Street and "F" Street frontages of the property and for them to be as steep as safely permissible along those lines To achieve the maximum safe extraction of soil affected by components of gasoline, the engineer may, at her or his sole discretion, permit over-steep slopes along the sides of the ' remedial excavation that parallel the streets, even if minor slope failure might threaten a degree of damage to the sidewalk paving However, under no circumstances will the extent or geometry of the excavation be configured such that there would be significant ' risk that slope failure may involve damage to utilities buried beneath the sidewalks If sidewalk paving is damaged, it will be restored according to the requirements of the City of Tracy Public Works Department ' Removal of Groundwater-qualityMonitoring Wells Excavation of soil over the area proposed will require the removal of existing groundwater-quality monitoring wells NAV 1 and NAV 3 Prior to that work being undertaken, a well-destruction permit will be obtained from the SJCPHS The wells will be 1 removed by carefully excavating around the casings so that they are exposed to the full depth of the excavation in their area(estimated to be 10 ft ), attaching a sling to the casing at the bottom of its exposed length and slowly puling the remaining buried length from the subsurface ' Destruction of these wells will be documented and the required reports will be filed with the California Department of Water Resources Estimated Volume of Contaminated Soil to be Removed For planning purposes, based on a pit 10 ft in depth excavated within the limits shown on ' Figure 6, it is estimated that a total of approximately 2,225 cubic yards of soil, as measured in situ, will be removed from the subsurface Of that total, it is estimated that 1,110 cubic yards will be clean overburden and 1,115 cubic yards will be contaminated by components of gasoline The actual volume of soil that will be excavated will be determined by the results of the analyses of soil samples recovered from the floor and walls of the excavation as the work progresses and by any restrictions on the depth or extent of the excavation that may be imposed at the direction of the geotechnical engineer in charge of the work