SITE INFORMATION AND CORRESPONDENCE

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jF ABLE 1 -CHECKLIST OF REQUIRED DATA FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES k Site Name and Location: I City of Ripon/Madsen Sunrise Dairy, 239 Stockton St,Ripon, San Joaquin County(RB#3391181) Y 1. Distance to production wells for municipal, domestic, A 2011 sensitive receptor survey reported no supply agriculture, industry and other uses within 2000 feet of the site. wells within 2,000'of the site(City reported two DWR- search wells abandoned due to Nestle groundwater lume. y 2. Site maps, to scale, of area impacted showing locations of Two 8,000-gallon and one 6,000-gallon gasoline USTs any former and existing tank systems, excavation contours and were removed 11/93;one three-compartment 12,000- sample locations, boring and monitoring well elevation gallon diesel UST was removed 11/09. The UST case is contours, gradients, and nearby surface waters, buildings, the 2009 diesel UST removal. streets, and subsurface utilities; 7Y 3. Figures depicting lithology(cross section), treatment system Site lithology consists of silt and sand to 39', the total diagrams; depth investigated. N 4. Stockpiled soil remaining on-site or off-site disposal (quantity); 77he amount and fate of the excavated soil is not discussed in the available reports. :Y::] 5. Monitoring wells remaining on-site, fate; one(1)monitoring well(MW--1) will be properly abandoned. 6. Tabulated results of all groundwater Depth to groundwater was 27'bgs. Groundwater flow direction from elevations and depths to water, nearby Nestle monitoring wells varied from north to northwest t abated results o =a1 s! amplin 7oC11'ZfaTa acle�{uatclYtabviarized tnvarious reports;including closure report and analyses: I Y❑ Detection limits for confirmation sampling ' �Y Lead analyses 8. Concentration contours of contaminants found and those remaining in soil and The extent of the identified groundwater, and both on-site and off-site: contamination is described in the available reports. Lateral and lVertical extent of soil contamination Lateral and Vertical extent of groundwater contamination 9. Zone of influence calculated and assumptions used for subsurface remediation An engineered remediation was not system and the zone of capture attained for the soil and groundwater remediation required by the lead agency. system; 10.Reports/information Unauthorized Release Form nY QMRs(2) 1-11 to 4-11 .0 Well and boring logs PAR FRP Fyj Other Closure Report(7-11). Yj 11.Best Available Technology(BAT) used or an explanation for not using UST removal and natural attenuation. BAT; Y 12. Reasons why background was/is unattainable Minor residual soil and groundwater contamination remains on-site. BAT, y 13.Mass balance calculation of substance treated Consultant estimates 11.93 lbs TPHd remains in soil. _ ____versus-that_remainin ;.__�_. 7w 14. Assumptions,parameters, calculations and Consultant states no significant risk exists, as TPHd in soil was Y model used in risk assessments, and fate and detected in the UST pit at 13'bgs(TPHd detected at 5'bgs was later transport modeling; identified as asphalt mixed with fill material)and the City of Ripon i plans to develop the site as a city park with no structures. TPHg detected in groundwater was identified as TCE from Nestle's plume . (TCE, maximum 75 ug/L). TPHd(maximum 420 ug/L in grab groundwater samples)was not detected in downgradient MW-1. Y 15. Rationale why conditions remaining at site will Soil and groundwater contamination reportedly are limited in extent .! not adversely impact water quality, health, or other Land use(future City park with no structures)is not expected to beneficial uses;and change in the foreseeable future. TPHd estimated to reach WQGs in i 2013. By: JLS Comments Two 8,000-gallon and one 6,000-gallon gasoline LISTS were removed 11/93;one 12,000-gallon diesel UST was removed 11/09. The UST case is the 2009 diesel UST removal at the subject site. Minor Date: residual UST soil and groundwater contamination remains on-site. Based upon the limited extent of 8/15/2011 contamination reported in soil and groundwater;no foreseeable changes in future-land use(park), and minimal risks from soil,soil vapor, and groundwater,Regional Board staff concur with San.Joaquin County's Closure Recommendation. ; ,1 t y