COMPLIANCE INFO_2014-2017 - Laserfiche WebLink

Home Browse Search

Brusca File No. 137-002 Page 3 August 10, 2017 Murphy Parkway Property Soil Gas Monitoring Workplan residual wastes at the site, and was conducted with regulatory agency oversight. AGE’s work included the performance of a significant number of test pits within the capped area, as well as onsite areas extending to the south and east of the cap. Additionally, AGE conducted a geophysical survey (involving ground penetrating radar and a magnetometer survey) on the westerly portion of the property to identify any unknown areas of disturbed materials/buried wastes. The geophysical work reportedly identified two areas (approximate 2,000 square feet each in plan area) of deeper disturbed materials/wastes along the far westerly margin of the property (see Plate 2). Subsequent excavation in these two areas revealed wastes extending to depths on the order of eight feet to 13 feet. The wastes encountered in these two areas reportedly consisted of glass, metal parts (such as vehicle window frame components) and minor plastics. AGE’s work included the remedial excavation/removal of the buried wastes (approximately 2,200 cubic yards) from these areas for offsite disposal at a Class II landfill; the remedially- excavated areas subsequently were backfilled with imported soil. It is reported that wastes exposed in the westerly walls of the remedial excavations were left in place at the westerly property line; as such, it is indicated that subsurface wastes likely remain offsite beneath the westerly adjoining property (former cogeneration plant at 17200 Murphy Parkway). AGE’s investigative work included the collection of a substantial number of samples of soil and waste materials for analytical laboratory testing. It is reported that the laboratory testing did not reveal significant chemical contaminant concerns associated with residual wastes at the site. In general, the residual waste materials (indicated to primarily consist of broken glass fragments) were determined to be inert and innocuous, and further investigative or remedial work was not recommended. As a part of their investigative work, AGE installed a soil gas monitoring well with the cap area on the property (see Plate 2). Sampling of this well reportedly has not revealed methane in soil gas at levels that would be a concern; the SJCEHD has indicated that the existing soil gas monitoring well can be abandoned in conjunction with the planned new monitoring well installation work. PROPOSED SITE DEVELOPMENT/CONSTRUCTION Redevelopment of the subject property is planned to be initiated later this year. The planned development includes construction of an approximate 870,000 square-foot commercial/light- industrial structure intended for use for warehouse/distribution purposes. The general location of the planned building is shown on Plate 2. The planned structure will be of tilt-up concrete construction with a concrete slab-on-grade floor. Onsite areas exterior to the building will support asphaltic-concrete and/or concrete pavements and very limited landscaping. Storm water basins are planned on the far northwesterly and southwesterly portions of the site. Project earthwork construction/grading will involve the disturbance, redistribution, and grading of soils across essentially the entire 48-acre parcel, including the capped area on the northwesterly portion of the site. The project specifications call for the complete excavation of loose soils/fill materials (including remnant buried glass waste) to expose underlying firm, native undisturbed soils. In some areas, the depth of required excavation to remove fills/wastes could be several feet or more. The excavated soils (and mixed-in glass materials) will be moisture