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RE_ Modeling & PCE SourcesFrom:Ivo Bergsohn To:"Reisch, Scott H." Cc:Bras, Alejandro Luis (ABras@mofo.com) Subject:RE: Modeling & PCE Sources Date:Thursday, April 27, 2017 4:17:34 PM Thanks Scott- -Ivo From: Reisch, Scott H. [mailto:scott.reisch@hoganlovells.com] Sent: Thursday, April 27, 2017 4:08 PMTo: Ivo BergsohnCc: Bras, Alejandro Luis (ABras@mofo.com)Subject: RE: Modeling & PCE Sources Thanks Ivo. EKI has provided a draft schedule and updated sampling map and I am awaiting final approval from the clients. Hope to have something for you tomorrow. Scott From: Ivo Bergsohn [mailto:Ibergsohn@stpud.dst.ca.us] Sent: Thursday, April 27, 2017 12:21 PMTo: Reisch, Scott H.Cc: Nick M. Billings Esq. (nick.billings@aimco.com); Peter.Cappel@aimco.com; asafford@ekiconsult.com; Paul B. Hoffey (phoffey@ekiconsult.com); Vera Nelson (vhnelson@ekiconsult.com); Bras, Alejandro Luis(ABras@mofo.com); Kyle Flory (kflory@pesenv.com); 'Greg Pohll'Subject: RE: Modeling & PCE Sources Hi Scott- I just wanted to follow-up to our conference call last Wednesday (4/19) and see if you got the information you needed from Greg P. It was my understanding that you were going to confer with EKI about the scheduling for the off-site investigation and then get back to me with a timeline showing when the analytical results from the groundwater sampling are expected. I’m open to delaying the start of the modeling runs for the remedial alternative scenarios, if the data collection from the off-site investigation is important to the F&T modeling effort. Given this need, I’d like to know if EKI will be incorporating the additional data collection recommendations provided by Greg at the end of his response letter; and if so, when the analytical results for samples collected from these critical areas (e.g., Auto Dealership Sites and Rockwater Apartment Site) would be available for incorporation into the model. FYI- During the SAG Workshop yesterday afternoon, Lisa Dernbach, LRWQCB informed the group that she did not expect to receive funding for LRWQCB’s Phase II off-site investigation until after the start of the fiscal year; and if funded, expected the investigation west of the South Y to be performed sometime during the fall of 2017. Thanks, Ivo Bergsohn, PG, HG Hydrogeologist South Tahoe Public Utility District 1275 Meadow Crest Drive South Lake Tahoe, CA 96150 (530)543-6204 From: Greg Pohll [mailto:Greg.Pohll@dri.edu] Sent: Thursday, April 20, 2017 12:09 PMTo: Reisch, Scott H.; Ivo BergsohnCc: Nick M. Billings Esq. (nick.billings@aimco.com); Peter.Cappel@aimco.com; asafford@ekiconsult.com;Paul B. Hoffey (phoffey@ekiconsult.com); Vera Nelson (vhnelson@ekiconsult.com); Bras, Alejandro Luis(ABras@mofo.com); Kyle Flory (kflory@pesenv.com)Subject: RE: Modeling & PCE Sources Scott and Alejandro, Per your request #3 below we have attached two files: 1. DRI Responses to South Y PCE Model Review April 20_2017.pdf 2. Data Package for Scott.zip – This contains the supporting data Please feel free to contact me if you have additional questions. Thanks. Greg From: Reisch, Scott H. [mailto:scott.reisch@hoganlovells.com] Sent: Wednesday, April 12, 2017 2:30 PM To: Ivo Bergsohn (Ibergsohn@stpud.dst.ca.us) <Ibergsohn@stpud.dst.ca.us>; Greg Pohll <Greg.Pohll@dri.edu> Cc: Nick M. Billings Esq. (nick.billings@aimco.com) <nick.billings@aimco.com>; Peter.Cappel@aimco.com; asafford@ekiconsult.com; Paul B. Hoffey (phoffey@ekiconsult.com) <phoffey@ekiconsult.com>; Vera Nelson (vhnelson@ekiconsult.com) <vhnelson@ekiconsult.com>; Bras, Alejandro Luis (ABras@mofo.com) <ABras@mofo.com>; Kyle Flory (kflory@pesenv.com) <kflory@pesenv.com> Subject: Modeling & PCE Sources Ivo and Greg, Thank you for including us in the meeting last week. We found it very helpful. Below are our comments on the email submitted by Greg last Friday (4/7/17), as well as some preliminary reactions and questions regarding last week’s model presentation. As noted below, we think a meeting in Lake Tahoe to discuss some of these issues is warranted. 1) The map provided in the 4/7/17 email does not include all of the potential PCE sources sites that we identified in our review of publicly-available files and other sources. On September 8, 2016, Hogan Lovells (counsel to Fox Capital) submitted a letter to the Water Board that described the results of our review. The Hogan Lovells letter was provided to you previously and is available on Drop Box. Selected pages from that letter that pertain to potential off- Site sources are attached to this email. Because of continuing concern that these possible sources have not been adequately investigated, last month Fox Capital notified the Water Board, by email that Fox and Seven Springs jointly plan to implement a groundwater investigation in the South Y Area. As shown on the attached map (which has been slightly revised from the one provided last month), a number of planned groundwater samples are to be located just downgradient of suspected source sites, including the former Lampson/Sierra dry cleaners site, as well as upgradient of the LTLW site to look for PCE that may be migrating onto the LTLW site from off-site areas to the south, including the Shop Street/Industrial Avenue area, which has been targeted by the Water Board as a potential source area for PCE contamination. Regarding upgradient sources, PCE has not only been detected in groundwater at the Tahoe Asphalt site (Industrial Avenue Well #4), but also at the Campora Propane Gas site at 1640 Shop Street. In a memorandum prepared by the Water Board, dated December 12, 1997 (see attached), it was reported that PCE was detected in a groundwater sample collected from the Campora site at a concentration of 24 ppb. The source for the PCE was never identified. We intend to complete the off-Site groundwater investigation as soon as weather conditions and permitting allows. This additional groundwater data, as well as subsurface lithology information that we plan to collect, would certainly be useful in running your remedial action alternatives simulations. 2) The location of the Redwood Oil site is incorrectly identified on your map. The Redwood Oil site is actually located at the southeast corner of the intersection of Dunlap Drive and Eloise Avenue. We understand that the Water Board has encouraged you to remove Redwood Oil from your map. Our experts do not agree and will address that point, as well as the TCI site, in a separate email to all stakeholders. 3) Our consultants have a number of preliminary questions and requests for additional information on the groundwater and transport model that was presented at the April 5th meeting: a. Please provide groundwater flow calibration data including simulated vs. measured headwithin the refined model area. b. What are the units for the y-axis identifying the PCE concentration of modeled sourcerecharge that is included on the slide identified as “PCE sources”? Also what is therecharge rate at the source that was used, the area over which the source rechargeoccurred, and the resulting PCE concentration in the groundwater within the cells directly beneath the recharge area in the 1st 2nd, 3rd and 4th layers within model overthe calibration period? c. What is the PCE concentration scale utilized to show the modeling results in the videos,as it is not readable in the presentation? d. Was Groundwater Vistas used to enter the data into Modflow and MT3D? If so, canthe original input files be provided? e. What are the simulated PCE concentrations relative to observed concentrations for thecalibration period from 1970 to 2016 for the Tata Lane Wells 1, 2, 3 and 4, the Julie LaneWell, South Y Well, LBWC4. f. Can you provide references for the effective porosity used within the model? g. Please provide a copy of the paper referenced as Benson, 2001. h. Please identify units for transverse dispersivity and vertical dispersivity presented onpresentation slide identified as “transport parameters.” Given the complexity of the model, the fact that critical information has not yet been shared with SSLP and Fox, and the fact that additional groundwater data on PCE sources in the South Y will be available in short order, we ask that you postpone your April 14 deadline for commenting on the model. We certainly understand your desire to move this process along. The fact that our clients have committed to voluntarily spend thousands of dollars to investigate other sources of contamination – something the Water Board should have done long ago -- shows that we share your goal. The April 14 deadline does not afford enough time for thoughtful review and input and we are concerned that rushing this process now will result in a flawed model, a waste of resources, and ultimately, further delays. We hope you will reconsider. We would like to meet with you in Lake Tahoe to discuss these issues and would propose April 19 as the meeting date. Please let us know if that date works for you. Thank you, Scott Reisch (counsel to Fox Capital) & Alejandro Bras (counsel to Seven Springs) About Hogan Lovells Hogan Lovells is an international legal practice that includes Hogan Lovells US LLP and Hogan Lovells International LLP. For more information, see www.hoganlovells.com. CONFIDENTIALITY. This email and any attachments are confidential, except where the email states it can be disclosed; it may also be privileged. If received in error, please do not disclose the contents to anyone, but notify the sender by return email and delete this email (and any attachments) from your system. PUBLIC RECORDS NOTICE: In accordance with NRS Chapter 239, this email and responses, unless otherwise made confidential by law, may be subject to the Nevada Public Records laws and may be disclosed to the public upon request. 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