55C - ALTON AVE OVERCROSSING @ SR 55

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Draft Findings of Fact and Mitigation Monitoring Reporting Program (applies to CEQA only) Although this site is not being partially or fully acquired by the proposed project, a groundwater sampling report conducted by Arcadis G&M, Inc. (Arcadis, 2004) for this site was reviewed due to the proximity of monitoring wells to the project location. Two of the monitoring wells are within the proposed project right-of-way. Testing results showed that concentrations of TCE and vinyl chloride exceeded the TCE and vinyl chloride Tap Water PRG. Acetone, carbon disulfide, and Freon 113 were also detected in groundwater sampling. Transportation Off-Site of Hazardous Waste/Materials Hazardous waste/materials that could potentially be located along the proposed project site, such as aerially-deposited lead (ADL), lead based paint (LBP), asbestos, traffic striping, contaminated soil, and contaminated groundwater, would be either transported within the project site or disposed off-site per applicable regulations. The presence of these materials can present a risk to workers and may increase the cost for handling and disposing of construction debris. The identification and quantification of materials to be transported (i.e., ADL, LBP, asbestos, traffic striping, contaminated soil, and contaminated groundwater) will be identified, where possible, as part of the appropriate evaluations that are included in Section 4.3.6 of the Final EIR/EA. Mitigation: Phase II testing was performed after the public comment review period for the Draft EIR/EA for the proposed project (Section 1.3). The following are the updated recommendations resulting from the ISA (1999), Supplemental ISA (2003), and Phase II ESA (2005): HAZ-1 HAZ-2 HAZ-3 During final design, the following information shall be developed: . Final determination of which sites will be fully or partially acquired . Determination of specific construction activities planned on or near each potential contaminant source, including any utility work . Development of site-specific hydrogeologic information, including geology and groundwater depth and direction . Additional in-depth review of agency records, and interviews with regulators and property owners/occupants of potential contaminant sources identified as a potential impact to the preferred alternative Dewatering is not expected at any of the of the acqUlslt10n sites with potential hazardous waste concern for the proposed project. However, if design details change so that dewatering is required at the sites listed above and once dewatering requirements have been determined, a study shall be undertaken to determine the effects of dewatering on groundwater flow pattern. Once these effects have been determined, the City shall determine if any liability is incurred as a result of the altered groundwater flow pattern. The City shall determine which monitoring wells located on Pullman Street, Duryea Avenue, and McGaw Avenue are within the limits of proposed construction, whether any monitoring wells can and/or should be relocated, and who is responsible for relocation of the wells. Alton Avenue Overcrossing at SR-55 K-15 April July 2005 55C-33