WORK PLANS - Laserfiche WebLink

Home Browse Search

1117 Lone Palm Avenue,Suite 201 YA�� Modesto,California 1 209-579.222-2221 Fax:209-579-2225 A 6 t O C 1 A r r e IMC. Hydrogeology Groundwater flow in the shallow zone beneath the site tends to be somewhat variable with eastward and northward components, but generally flows in a radial pattern towards JLM3. The magnitude of groundwater flow in the shallow zone has been calculated to range between 0.001 ft/ft to 0.005 ft/ft, or approximately 5 to 26 ft/mile. Limited available data indicate groundwater flow in the intermediate zone beneath the site trends toward the south at rates ranging from 0.002 ft/ft to 0.010 tuft (I I to 53 ft/mile), and groundwater flow in the deep zone is toward the northwest at rates ranging from 0.0006 ft/ft to 0.006 ft/ft(3 to 32 ft/mile).A summary of groundwater monitoring data is presented in Table 1. Groundwater elevation levels were measured in monitoring wells JLM3, JLM4, JLM5, JLM12, JLM13, JLM14, JLM15,and JLM17 through JLM26 on March 2, 2009. Water levels in the shallow groundwater wells (JLM3,JLM4, JLM5, and JLM12 through JLM19) ranged from 21.87 to 23.07 feet below the tops of the well casing elevations. Water levels in the intermediate zone wells (JLM20, JLM21, and JLM22) ranged from 22.96 to 23.85 feet below the tops of the well casing elevations. Water levels in the deep zone wells (JLM23, JLM24, and JLM25) ranged from 22.49 to 23.13 feet below the tops of the well casing elevations. SITE CONTAMINANTS Soil The majority of petroleum impacted soil appears to have been removed during excavation activities conducted at the site in late 1995. Field observations conducted by ATC personnel during subsequent drilling activities at the site have not identified the presence of petroleum impacted soil. Additionally, selected soil samples submitted by ATC for laboratory analyses have been negative. Groundwater The lateral extent of the shallow groundwater plume appears to be adequately defined for the analytes of concern. Monitoring well JLM13 located in the central portion of the site is the most impacted well.The presence of 1,2-dichloroethane (1,2-DCA) and/or methyl tertiary butyl ether (MTBE) in samples collected from JLM20 through JLM23 suggests the vertical extent of the groundwater plume has not been completely defined in the northern portion of the site. Laboratory analytical data indicate groundwater at 141 feet bgs is impacted in the southern portion of the site at JLM26. A summary of historical laboratory analytical results of groundwater samples is presented in Table 2. The monitoring well locations are shown on Figure 3. GEOLOGIC COMPARISON OF OTHER SITES THAT HAVE HAD OZONE PILOT STUDIES ATC staff reviewed Geotracker information and conducted a regulatory file review of three additional sites where ozone pilot studies have been conducted to see if sufficient similarities exist to warrant foregoing of bench scale testing at the subject site. These sites are located at 515 West Chatter Way in Stockton, 601 East Miner Avenue in Stockton, and 16 Cherokee Lane in Lodi, and are approximately 4 miles, 5 miles, and 17 miles north of the subject site, respectively. The ozone pilot conducted at 16 Pilot Testing Workplan—J R L Mmket ATC Associates Inc. 5:...1285891 Reports ATC Project No.54.28589.0001 3