SITE INFORMATION AND CORRESPONDENCE

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Vicki McCartney [EH] From: Nuel Henderson [EH] Sent: Wednesday, March 11, 2015 11:31 AM To: 'Daniel Villanueva' Cc: Vicki McCartney [EH] Subject: RE: Quick N Save #1 - Phone Conversation 03/11/2014 i d Daniel, Just wrote most of that in the case narrative. According to my memory we discussed aspects of the installation of MW-5; AGE considering the screened silt interval part of the overall sand interval, but my concern that the reduced permeability (and unmentioned higher surface area of the particles) of the silt retards contaminant migration compared to the sand, so the coarser interval should have been screened to provide more contemporary information on what is potentially in migration. We then discussed in general terms the CSM with a shallower sandy interval around 40 feet bsg and the deeper sandy interval nominally 75-80 feet bsg . My concern is that the shallower sandy interval is not well characterized east of EI Dorado and I think it would save time and money to get some basic information on the interval, hard data to complement the CPT data, while further characterizing the deeper zone known to be impacted. You want additional deeper zone information onsite to assist relating the contaminant distribution observed east of EI Dorado to the source area. You proposed collecting soil and groundwater samples through the shallow zone during installation of the proposed deeper zone wells (nominally 75-80 feet bsg) and installing shallow zone wells in the initial boring if field indications of contamination are encountered, and then moving over a short distance to install the deeper zone well. This is acceptable to me, but we should be working from a common CSM; to address these changes and conditions, I asked you to provide a work plan addendum that: 1 ) Provides a narrative form of the CSM identifying the intervals of interest; 2) Sampling soil and groundwater through the shallower zone to assess for contamination, especially in the shallower sandy unit; 3) Specifies that shallower zone monitoring wells to be installed if field indications of contamination are encountered and completing the currently proposed deeper wells (-75-80 feet bsg) in a separate boring; and 4) Describing the decision criteria for selecting the final screen interval for each of the wells based on field observations. We also agreed that the report of findings for this scope of work would include an updated CSM with revised cross sections. If I missed anything, please let me know. Nuel From : Daniel Villanueva [mailto :dvillanueva(abadvgeoenv.com] Sent: Wednesday, March 11, 2015 10: 53 AM To: Nuel Henderson [EH] Subject: Quick N Save #1 - Phone Conversation 03/11/2014 Hi Nuel, Thanks for taking my call this morning and discussing the offsite assessment work plan with me . I am looking over my notes and I am having a hard time figuring out exactly what EHD is requiring AGE to prepare for an addendum to perform the proposed offsite assessment. Can you provide me with an email that lays out exactly what EHD is looking for in order to move forward with the offsite assessment proposed. Thanks, Daniel Villanueva Project Geologist t