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Abandonment of Groundwater Monitoring Wells Work Plan Page 2 Lodi Central Plume Source Area,Lodi,California March 23,2024 The combined VOC plume well network consisted of 76 monitoring wells constructed in four progressively distinct and deeper groundwater zones. Of these wells, forty (40) were installed in the Shallow Zone, thirteen (13) were installed in the Intermediate Zone, seven (7) were installed in the Deep Zone, and sixteen(16) were installed in the Deeper Zone. On January 11, 2018, the Water Board issued the revised MRP Order No. R5-2018-0800, which reduced the sampling and reporting frequency from quarterly to semi-annually, and provided revised monitoring, sampling, and reporting requirements for the City VOC plumes. As the groundwater VOC plumes migrated and evolved in size and shape over the years due to source area remediation and dilution, the continued monitoring of some of the existing wells provided limited information to the extent of the VOC plumes. On behalf of the City of Lodi, CHT submitted the Proposed Revisions to Monitoring and Reporting Program No. R5-2018-0800 (Proposed Revisions)dated 28 March 2023,which provided justification and rationale for reducing the monitoring well network. The proposed revisions were approved by the Water Board in their revised Monitoring and Reporting Program (MRP) Order No. R5-2024-0800 on January 29,2024. The revised MRP reduced the monitoring well network from 76 to 55 wells. SCOPE OF WORK The City requests the Water Board's concurrence to perform the following well abandonment activities. PRE-FIELD ACTIVITIES Prior to commencement of field activities, the following pre-field activities will be completed: Health and Safety Plan (HASP)Preparation—A Site-specific Health and Safety Plan(HASP)will be prepared and utilized in accordance with 29 CFR 1910.120 and Title 8 California Code of Regulations Section 5192 to address potential hazards at the Site during the proposed field activities. The HASP will be reviewed, signed, and adhered to by all onsite personnel including field staff, subcontractors, and Site visitors during the performance of the fieldwork. The HASP will include project objectives, assessments for potential hazards which may be encountered at the Site and associated with chemicals of potential concern (COPC), personal protective equipment and personnel monitoring, Site organization, and emergency contacts. The HASP will remain on- Site during all fieldwork. Site Access,Permitting, and Notifications—The following requisite permits and access agreements will be obtained prior to the onset of drilling activities ➢ Obtain permission from the facility owner, if needed, for wells located on their property. ➢ CHT will obtain an Encroachment Permit from the City to abandon wells in the public right of way. 581 MONTEGO TERRACE,SUNNYVALE,CA 94089 TEL:415-424-3009