CORRESPONDENCE_2007 (1/07 - 6/07)

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s I am cc`hhcerned about plugged robes and lack of readings preser— d in the reports. Apparently, there are several probes plugged with water, GW -1 and GW -2 that are known for sure. The reports SJC submits to the board does not include field data sheets for monitoring of gas wells, so I am not sure what SCS is doing. I am concerned that other probes could have water in them and whether or not groundwater has risen into the waste. Do we know what the probe depths are relative to the extraction wells? If similar can we assume the extraction wells located in the northeast portion of the landfill might have water in them, hence water in the waste? Are the probes open to the atmosphere and can DTW be checked? If not,how do we know water is in the probe? I have not recommended this yet, but any probes with water west of the northeast boundary where GW -1 is located be left in place and that DTW measurements and groundwater samples be collected from them. Until additonal GW wells are installed I would like to have those points for backup. As far as the phase II plan SJC has proposed, I have made several recommendations to further investigate the areas of concern and extend the cover where needed. We will make a final detemination of the performed activities following completion. Gino, the May lst 2007 timeline is OK with me to fix the ponding issues. Todd A. Del Frate P.G. Engineering Geologist Waste Discharge to Land Unit Central Valley Region - RWQCB 11020 Sun Center Drive, Suite 200 Rancho Cordova, CA. 95670 Ph: 916-464-4737 fx: 916-464-4775 >>> "Yekta, Gino" <GYekta@CIWMB.ca.gov> 3/23/2007 3:19 PM >>> Thank you for meeting with the operator to discuss the ponding issue. If the May 1, 2007 timeline is okay with the RWQCB, then we are okay with that as well. Here are responses to your questions (in the same order of your questions): #1 - I am not sure if there is anything that specifically constitutes a plugged probe. I suggest that you can tell if a probe is plugged by finding water and sediment in it that would keep the gas from migrating into it, filled screen levels and such, but water seems to be the culprit in making probes plugged. #2 - No, it is not. You could sample all or a few of the probes, that is up to you. #3 - I have reviewed the submittal. Our comments and suggestions are similar to RWQCB's and we would like to defer to RWQCB in regards to closure of this portion of the site. #4 - We are okay with any one of the options as long as it is designed, constructed and installed adequately. -----Original Message ----- From: Robert McClellon [EH] [mailto:RMcClellon@sjcphs.org] Sent: Tuesday, March 20, 2007 9:55 AM To: Yekta, Gino Cc: Wochnick, Michael; Todd Del Frate; Natalia Subbotnikova [EH] Subject: RE: Corral Hollow Sanitary Landfill inspection Gino, here is what I was able to find out. The ponding on Corral Hollow still remains. I spoke with Michael Carroll and met with him and his staff at the landfill on March 19, 2007. The ponding located south east of the landfill is at the toe of the slope and near the secondary storm pond. Michael Carroll disclosed that there was another area of ponding on the south west corner of the landfill that they found during the site visit (at the toe of the slope). In conversation Mike agreed to regrade the areas and eliminate the ponding (they are small area's 5ft x 20ft) by May 1, 2007. During the site visit Probe 6 was tested. We tested the probe by placing a "T" in the line between our landtec and used 2