RE_ Modeling & PCE Sources 2From:Reisch, Scott H.
To:Ivo Bergsohn
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
Date:Monday, May 1, 2017 9:16:55 PM
Attachments:Seven Springs-Fox South Y Area Groundwater Investigation Sample Map 4-25....pdfSeven Springs-Fox South Y Area Groundwater Investigation Schedule 4-28-2....pdf
Ivo:
Attached please find an updated sample location map and schedule for Seven Springs/Fox’s South Y
area groundwater investigation.
Sampling Map. We have revised the map to reflect additional samples near the former small engine
repair buildings as we understand that this is an area of interest to both STPUD and the Regional
Board, and there are no other current plans to complete sampling in that area. We also have added
an additional sample near the 5th Street businesses.
Schedule. The schedule is controlled by the time required for regulatory agencies to process and
approve permit applications, particularly the encroachment permit from Caltrans that will be needed
to conduct sampling along Lake Tahoe Boulevard. The schedule for completing contingent tasks will
be adjusted to reflect dates that permits are actually obtained. Please note that we have adopted
your suggestion and split the sampling into two separate events so that the sampling that does not
need a Caltrans permit can be completed sooner.
In addition to the South Y area groundwater investigation reflected in these documents, E2C is
planning to conduct its second quarter monitoring event at the Lake Tahoe Laundry Works site
(LTLW) in May. This event will include sampling the deeper zone monitoring wells LW-MW-1D, LW-
MW-2D, and LW-MW-5D at the LTLW site.
As discussed previously and in light of the expanded scope, Fox and Seven Springs renew their
request that you postpone the modeling effort until the results of this effort are available.
Thanks for considering this.
Regards,
Scott & Alejandro
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.
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