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12 December 2014 AGE Project No. 12-2169 Page 3 of 7 should adequately provide data that can be evaluated to determine if technology is suitable to remediate or reduce high dissolved and suspected, deep adsorbed hydrocarbon concentrations at the site. AGE has used this approach at several other sites in San Joaquin County and has had success evaluating the technology using this quantity of media. Furthermore, the overall limited area of hydrocarbon impact at the site, warrants a smaller dose of injection over the proposed six week period. CVRWQCB Comment 3: Performance monitoring should include non -injection wells (MW -6, MW -7S, MW -81, VM -1 and VM -2) to fully evaluate the efficacy of the remedial approach. These non -injection wells should analyzed for the chemical analyses presented in section 4.1. of the Work Plan. To evaluate performance of the pilot ISCO injections, as well as adverse conditions, monitoring event will be performed once following the second proposed injection event and two months following the final injection event. Monitoring and sampling will be conducted using wells B3RNW-1 D, B4R/VW-2D, B5R/VW-3D, MW -4R -D, MW -7S, MW -81, MW -91 and MW -101 (Figures 1 and 2). All wells will be monitored and sampled as described in Comment 1. CVRWQCB Comment 4: A review of the proposed injection wells and Site drawings indicate that the quantity and distribution of the proposed injection wells leaves an inadequate monitoring well network for the Site. Wells used for injection are not suitable for use as monitoring points as the water chemistry will have been altered as a result of the injection of the hydrogen peroxide solution Central Valley Water Board staff request that AGE evaluate the proposed injection wells and either reduce the number of injection wells to allow sufficient monitoring or recommend the installation of additional wells to adequately monitor the results of the injection. Based on Regional Board comments, AGE recommends installing two dedicated shallow injection and two intermediate injection wells is areas as described below: • One shallow injection well will be installed north of the eastern most UST area and north of historically impacted well MW -4R -D; • One shallow injection well will be installed at the southern end of the eastern- most UST area and north of historically impacted well MW -7S; • One intermediate injection well will be installed southwest of historically impacted well MW -91 and in the apparent core area of the intermediate dissolved plume; and • One intermediate injection well will be installed north of historically impacted well MW -81 and in the apparent core area of the intermediate dissolved plume. Advanced GeoEnvironmental, Inc.