25C - AGMT - RIGHT-OF-WAY DEMO SURVEY AND ENVIR ASMT SRVS

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ANNINk QPCIty of Santa Ana • Feasibility studies and remedial alternative evaluation, • Corrective action plans and risk based corrective action plans. • Remedial design plans and specifications. • Construction cost estimating. • Construction management, • Community relations, Phase 11 site Investigations are conducted to verify the presence of constituents of concern and, as applicable, to define the concentration and spatial extent of these substances. Phase 11 site Investigations may be conducted based on findings from a Phase I ESA, in response to regulatory agency concern, because there is some indication contaminants are present, or as follow up to previous phases of site investigation findings. Investigation techniques may include hand augers; direct-push, hollow-stem auger, air rotary, and/or sonic drilling methods; or exploratory excavations such as trenches and potholes. Soil and soil vapor samples may be analyzed using on-site mobile laboratories or off-site fixed-based certified laboratories. Groundwater samples may be collected using grab, traditional, and low flow sampling techniques. Expedited analysis may be used when appropriate. Phase lI site Investigations are completed according to generally-accepted regulatory guidance and in accordance with permits. A phased approach is often used in Phase II site Investigations, wherein a limited number of samples is collected from suspect areas to assess the potential for contamination as established by the conceptual model and data quality objectives. If analytical results for this "first phase" of samples indicate that contamination is present, a more comprehensive sampling effort may be recommended to more fully delineate the extent of the impacted area and affected media (soil, soil vapor, and/or groundwater). Once the release has been properly characterized, the data are used to evaluate remedial alternatives and estimate site cleanup costs. These subsequent phases may or may not be conducted with regulatory agency oversight. SCS consults with clients and their legal counsel to determine when regulatory agency involvement is recommended. Other factors that are key to developing an investigation approach include area access; overhead clearance; locations of utilities or other possible subsurface obstructions; traffic control; and health and safety considerations, including establishment of work and exclusion zones. At the end of a Phase 11 site Investigation, a report is submitted, outlining the procedures used during the field investigation and the type and extent of contamination encountered. The site investigation report includes background that discusses site characteristics and rationale for sampling approach, review of field activities, boring or sample logs, a description of sampling protocols, analytical results, and conclusions regarding the extent of contamination, if any, detected by the investigation. Supporting documentation-such as figures, tables, cross-sections, 19 25C-126