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TAC Proj Mtng 4 02262019_NotesSOUTH TAHOE PUBLIC UTILITY DISTRICT TAC Meeting 4 South Y Feasibility Study of Remedial Alternatives(D17125081) Tuesday, February 26, 2019 10:00 AM- 1:00 PM Attendees: Greg Pohll, Dessert Research Institute; Susie Rybarsici, Dessert Research Institute; Jennifer Lukins, Lukins Brothers Water Company; Jeff Brooks, Lahontan Regional Water Quality Control Board; Abby Cazier, Lahontan Regional Water Quality Control Board; Ivo Bergsohn, South Tahoe Public Utility District; Paul Hughes, South Tahoe Public Utility District; Brian Grey, Lahontan Regional Water Quality Control Board; Kirk Wooldridge, Tahoe Keys Property Owners Association; John Thiel, South Tahoe Public Utility District; Julie Ryan, South Tahoe Public Utility District; Starlet Glaze, South Tahoe Public Utility District; Sachi Itagaki, Kennedy Jenks Consultants (Via Teleconference); Meredith Durant, Kennedy Jenks Consultants (Via Teleconference); Jennifer Lau, Kennedy Jenks Consultants (Via Teleconference); Trisha Carter, State Water Resources Control Board-Division of Financial Assistance (Via Teleconference); Robert Reeves, State Water Resources Control Board-Division of Financial Assistance (Via Teleconference); Salvador Turrubiartes, State Water Resources Control Board-Division of Drinking Water (Via Teleconference); Scott Ferguson, Lahontan Regional Water Quality Control Board; Gary Kvistad, Brownstein Hyatt Farber Schreck (Via Teleconference); Jason Burke City of South Lake Tahoe; Alice Robinson, Kennedy Jenks Consultants (Via Teleconference). 1) Welcome/Self Introductions 10:00 • Correction to Agenda: Item 4, PDI Draft Report will be presented by Kennedy Jenks Consultants (KJC) and South Tahoe Public Utility District (STPUD). 2) Groundwater Model Scenario Evaluation 10:10 a) Scenario Development (KJC) • Sachi Itagaki gave a slide show presentation describing the Groundwater Model Scenario development and an overview of the Scenarios 1-5 (See Attached – Exhibit A). • Scenario development started with Initial model runs where DRI took the regional scale model, scaled it down and intensified the grid in our interested area and ran baseline runs as well as targeted runs. • KJC conferred with the other water purveyors and then guided DRI over the course of 4-5 months to arrive at the scenarios that will be presented today. • The Potential Well locations came after discussions with the water purveyors. For the purposes of modeling they focused in and replaced the Tahoe Keys well #1 with the well C location and did another run with the replacement well D location. For Lukins Brothers, the run was near the well D location. • There were no questions from the TAC group regarding the process. • Sachi Itagaki reviewed the scenario development alternatives modeled and noted that the bolded scenarios were those chosen for DRI to run further modeling studies. • Robert Reeves asked why Replacement Well #2 was chosen for the DRI analysis rather than Replacement Well #1. • Sachi Itagaki said that during the initial scenarios, Replacement Well #1 (C) was a little bit closer to the plume so it had the potential for pulling the plume closer in the model so Replacement Well #2 (D) was chosen for further analysis. b) Findings and Results(DRI) • Susie Rybarsici gave a presentation of the model simulations used to forecast the effectiveness of the modeling scenarios proposed to address the PCE plume (See Attached -Exhibit B). • Scenarios included;1A & 1B, Baseline and Conservative Baseline; 2A & 2B, Extraction Wells; 4B & 4C, Replacement Wells RW-D & RW-F; 4B & 4C, Replacement Wells RW-D & RW-F (Correction: Slide should read TWC1 pumping moved to RW-D); 5A & 5B, Max Supply Well Pumping; • Ivo Bergsohn asked how close RW-D and RW-C were to approaching the MCL. Sara said that RW-D had exceeded the MCL and RW-D came close. • Sachi Itagaki wanted to remind everyone that part of the reason we have been carrying on with the conservative worst case is because the Lukins Brothers #5 Well has had hits in the 60-80 ppb range. We think the reality is somewhere in between the baseline and the conservative. • Ivo Bergsohn said that another reason to highlight the conservative, is that as DRI has been developing the model there have been results found by the responsible, parties as part of the off-site investigation, that have shown new hives as far as concentration. Recognizing that was another reason for the conservative bookend. • Robert Reeves asked for confirmation that the Replacement Well Scenario (4b & 4C) shows the extent of the contamination expanding because of the Replacement Well Scenario. • Susie Rybarsici said yes, it is pulling the plume to the East, same amount of mass, but spread out over a larger area. • Ivo Bergsohn said that the pumping rates are based on the annual averages not the source capacities. We looked at the annual average for the wells to drive the rates for the model. c) Discussion (TAC) • Ivo Bergsohn asked if the group had any questions regarding the handouts or presentation. • Sachi Itagaki asked if there were any clean up options that the group would like to see ran. Everything else that she is going to propose will be refinements to fine tune this. • Jennifer Lukins asked if we have ever run anything on the Lukins Brothers Well #4 site. Potentially moving the air stripper down to that location and combining the air stripper to the 2 GAC sites to see the increase. • Sachi Itagaki agreed this was a good thought, but the well itself is not usable based on the evaluations. • Ivo Bergsohn, we could try to drill a replacement well and try to seal it off in the low permeability aquifer at layer 3 and see what kind of promise that would be. Not sure what level of treatment there would be needed to support that. • Robert Reeves said that the replacement well scenario at Lukins Brothers #4 showed that the plume would expand. Wondering why we did not do a scenario involving Lukins Brothers Wells #3 & #4 as clean up wells. • Ivo Bergsohn said that Lukins Brothers Well #3 has been destroyed and the problem with modeling an extraction well for Well #4 is because of its construction. If you use that as an extraction well you would exacerbate the problem and draw the contamination more down into layer 2 and that would possible make layer 3 more prone to contamination as well • The future thought for Lukins Brothers Well #4 from the work that STPUD did in 2016, was to destroy the existing well and if an extraction well was developed on that site it would have a proper design. Ivo Bergsohn thinks this is somewhat modeled in Scenario 2. Also, a deeper replacement well alternative may have some merit. • Robert Reeves-fundamentally if we went forward and applied for implementation funding the State would have to look at it to see if these were good remediation wells that would contain the plume. Funding is not available for replacement water supply wells. • Robert Reeves thought that there were still some data gaps that were not in the PDI report. We need to resolve how we are going to resolve the data gaps before identifying the preferred alternatives. • Meredith Durant asked why the State can’t fund replacements wells. • Robert Reeves said that replacement wells are usually put in to clean aquifers. The funding is for human health and to fund projects that would provide remediation, not new drinking water wells. • Robert Reeves agrees with Ivo Bergsohn that Lukins Brothers Well #4 should be abandoned, if a new extraction well in that location would potentially spread the plume into a deeper layer potentially contaminating drinking water. It is up to the utility district to determine if they want to submit this in the funding application but it does not seem to be a feasible solution for extraction. • Sachi Itagaki asked if aside from running scenarios on pumping at Lukins Brothers #4, is there anything else that KJC can run. • Ivo Bergsohn asked Sachi Itagaki to put together a summary table of pros and cons for running that simulation to distribute to the TAC group after the meeting for comments. We don’t want to direct DRI to do modeling based on this conversation. • Meredith Durant asked, if we put together an alternate that included mid plume remediation and some replacement wells to provide clean water to people down gradient of the mid plume, would DFA be able to fund the whole measure or only the component dealing with remediation of the plume. • Robert Reeves said in the guidelines DFA can fund remediation or prevention projects. If the replacement well is determined to be part of the clean-up effort then yes the State could fund a replacement well that would clean up or prevent migration of the plume. • Brian Grey said that Lahontan agrees with Ivo Bergsohn’s concerns about Lukins Brothers Well #4 and its abandonment but if that site could be used for future evaluation they would be willing to explore that location. Acting as a potential vertical conduit for the plume and then whether or not we could use a replacement well at that location is a reasonable discussion. • Jennifer Lukins said that she had spoken with Salvador Turrubiartes about abandoning Lukins Brothers Well #4 and applying for a permit to replace it. The thought was to possibly add Lukins Brothers Well #4 as part of the max pumping to treat as much water as we can as part of scenario 5. • The Replacement well would be at whatever targeted zone that it would be most effective. We can possibly look at alternatives at what to do with the extracted water rather than treating it and putting it back in to the system. Cost is a concern. • Ivo Bergsohn said that there will be time to further discuss options. • Robert Reeves-there are significant data gaps in particular to the east. That needs to be evaluated especially with the possibility of putting in a replacement extraction well at Lukins Brothers Well #4. There should be some acknowledgement that there are data gaps and where they are. 3) Feasibility Study 11:10 a) Potential Alternatives (KJC) • Sachi Itagaki gave a presentation on the refined alternatives and noted that we will need to keep in mind going forward what the grant will fund (See Attached – Exhibit C) • The potential alternatives based on the groundwater model include: 1.) do nothing; 2.) use of new extraction wells to remove the PCE plume; 3.) use of new Public Water Supply wells located outside of the plume for alternative water supply; and 4.) use of existing impaired Public Water Supply wells with wellhead treatment to remove the PCE plume. • Of the scenarios presented by DRI the use of impaired Public Water Supply wells with well head treatment resulted in the largest reduction of the PCE plume. • Meredith Durant wanted to reinforce the concept that for each of these alternative there is a huge data gap due to the fact that pilot studies have not been done. The pilot studies will require additional funding and take time. • Robert Reeves said that in hearing this, STPUD could apply for GAP funding as well. Especially the mid-range value source areas could be looked at more further with SCAP funding. This may be something to pursue as another funding option. • Ivo Bergsohn asked if the SCAP funding that Lahontan receives will be used to collect field data to better inform the model as far as source and biodegradation terms. • Jeff Brooks said it is a timing issue on when Lahontan will get the funding as to what it will be used for. • Robert Reeves said that the can’t speak as to how quickly the SCAP funding will be available. But perhaps STPUD could apply for SCAP funding to build on the modeling that has already been done. Maybe a piggy back on what the Regional Board does with their funding to do some kind of implementation project that could include tertiary cleanup. • Robert Reeves wanted to make a point clear that he thinks that we have already determined that doing some kind of mid plume clean-up effort is going to have a huge cost associated with it. Ultimately the Prop 1 program is not the best funding source. • The SCAP program would be a better road to follow. The Prop 1 funds could fund a Well Head Treatment Program for Tahoe Keys and Lukins Brothers wells but ultimately there will not be any money left in the next few years. • Robert Reeves said if STPUD gets funding in the third round and we decide to do implementation and put in a larger GAC system, and want funding for operating and maintenance, there is some Prop 668 funding available in 2020 for existing treatment systems. However, the work would need to be done this year. • Sachi Itagaki asked if we had to develop infrastructure and piping to enhance pumping though STPUD as a Capital Project would that be something that the State would consider for funding. • Tricia Carter said that yes, that would be something that the State would consider for funding. • Sachi Itagaki said that at some point we want to outline options but we are also trying to set up the feasibility study to support an implementation grant. • Robert Reeves said the State could also fund well abandonment as part of a implementation project. • Jeff Brooks asked if DFI would potentially help fund Lukins Brothers Well #4 decommissioning. Lahontan is looking at the best placement for the SCAP money. • Jennifer Lukins said the problem with using the Prop 1 money for that is that the DFA process takes too long. Time is of the essence. • Jeff said it looked like Lahontan will have the SCAP money this Summer • Ivo Bergsohn asked if Lukins Brothers could do the work and then submit it to the State for reimbursement. • Jennifer Lukins said that would be a DFA question. b) Preliminary Alternatives Screening (KJC) • Jeff Brooks wanted to clarify the data gap concern voices by Robert Reeves. This was why Lahontan applied for the SCAP funding because they do not have enough data to connect receptor to source. • Robert Reeves clarified that when the DFA sees the terms “replacement well” and “avoiding contamination” they can’t fund something like that. They can fund pretty much anything else associated with remediation and prevention. If it is a new supply well is falls under the drinking water SRF. • Ivo Bergsohn said that he thinks that the modeling results show that there is a balance of replacement wells that give you the opportunity to do ground water use without treatment; However, it causes the plume to spread. He agrees that KJC does not have a scenario that checks all of the boxes but it boils down to how many boxes can we check off. • Robert Reeves said that he doesn’t think that the objective should be to know everything. The point was made that this could be an interim clean up method. If we can get this rounded up this year and fine tune the alternatives then we should be in good shape for round three funding. • Sachi Itagaki provided a summary of the GW Model results and pumping scenarios(See Attached - Exhibit D). • The pumping to Tahoe Keys Well #2 could be increased to see how beneficial that will be. KJC has some numbers from a prior model run but it becomes a values evaluation. We may have to go offline and reduce the pumping from the STPUD wells to really maximize that water. • Ivo Bergsohn said that he was pretty sure that we could do that. Reducing production from STPUD wells is probably not that big of a problem. We need to verify that the infrastructure is there to make that quantity of water and move it around • Jennifer Lukins said there is also the added cost for Tahoe Keys to build the infrastructure and produce the water. It should be balanced out for water sold to STPUD, but STPUD shouldn’t be paying for water that they can technically produce themselves. • Sachi Itagaki said that our scope is to develop three alternatives. Putting this back onto the water agencies, do Lukins Brothers and Tahoe Keys want to look at replacement wells for the future regardless of if they are fundable under Prop 1. Both Jennifer Lukins and Kirk Woodridge agreed. • Jennifer Lukins said that Lukins Brothers is losing Well #2 as their source. Ideally they need to find a source out of the plume area. They have to have the availability to have the same amount of sources that they once had. • Sachi Itagaki asked Robert Reeves and Trisha Carter if this meets with DFA’s understanding of what an alternative looks like for a Feasibility Study. Robert Reeves said yes. • Robert Reeves asked if we ended up with a recommended alternative that included Tahoe Keys and Lukins Brothers as the wells that are going to enhance the cleanup of the VFD Plume, would they both by themselves apply for funding or would STPUD apply for funding to put in GAC for those wells. • Sachi Itagaki said that Tahoe Keys Well #2 already has GAC, they would just be operating at a higher rate. Lukins Brothers has a system design for their Well #5 and is currently working thorough the details of getting funding for the construction. The recommended alternative that would be needed is to upsize infrastructure to be able to deliver that water back for beneficial use to STPUD. • Robert Reeves asked if Lukins Brothers and Tahoe Keys would apply separately for implementation or would STPUD. • Jennifer Lukins thought all three agencies would have to apply. Lukins Brothers and Tahoe Keys for O&M funding and STPUD for funding to purchase water once the infrastructure is in place. • John Thiel said that he isn’t sure of the answer, but would agree with whatever if the most beneficial. • Paul asked if the application source made a difference. • Robert Reeves said that it might be easier to have one applicant apply for funding. • John said ok, it sounds like one would be the preference. We will see what we can work out. • Ivo Bergsohn said we will need to have discussions internally and have the cost sharing agreements worked out before we submitted the application in 2020. c) FS Report – Outline (KJC) • Sachi Itagaki reviewed the Feasibility Study Outline which included the Work Plan with the group(See Attached - Exhibit E). • DRI is working on a model that will be an appendix as well as the PDI Report which will be another appendix. • Sachi Itagaki said they are not going to take feedback on the draft outline right now but they are continuing to develop it. • Sachi Itagaki asked Jeff Brooks if any remediation from the responsible parties that have been identified is a ways out. • Jeff said they have been talking to Lake Tahoe Laundry Works about a little bit deeper clean up on their property but the other central sources are a ways off. They are trying to finish looking at the other properties potentially with the SCAP funding. • Ivo Bergsohn asked Jeff Brooks if Lahontan had any idea what the likelihood is of additional source areas being identified in the near future. • Jeff Brooks said that it is a possibility. The primary right now is to fill in the original gaps, then century wells, and then other source properties. • Brian Grey said that he doesn’t think they are really anticipating very many more major sources. • John Thiel asked if the letter to the potential properties had gone out last month. • Jeff Brooks said no, the letters will go out this month. • Ivo Bergsohn told Sachi Itagaki that based on today’s meeting, we need to have a data gap section in the front portion of the feasibility study to explain that this is for the interim remediation project or put it in a section in the back. • Jeff Brooks said that Robert Reeves is just looking for an acknowledgement of what we don’t know. • Ivo Bergsohn said that it sounds like there is a question of the status of remediation and potential timing at the source area that will not be resolved before the project wraps up in June. However, we can get input from the regional board. d) Discussion (TAC) • Robert Reeves discussed the requirements for funding through Prop 68, which is in development, including the need to have a system in place for remediation that could be optimized with the funding if received. • Ivo Bergsohn asked Sachi Itagaki if we need to reach out to the City regarding additional permit requirements. Sachi Itagaki said they can add some topics within section 10. This is a draft so any input would be welcome. 4) PDI Draft Report (Kennedy Jenks and STPUD) 12:10 a) DFA Comments • Sachi Itagaki presented a summary of the finding of soil and groundwater data collected during the PDI as results to findings and conclusions. (See Attached - Exhibit G). • Trisha Carter said it was more appropriate to address the issues through the PDI for the DFO. The effort was appreciated. • Sachi Itagaki said that the PDI will be wrapped up in the next couple of weeks including filling in as many data gaps as possible. b) Proposed Changes • See above c) Discussion (TAC) • See above. 5) Upcoming Activities 12:40 a) Public Workshop 4 (3/06/2019) • Ivo Bergsohn notified the group that a Public Workshop had been scheduled for 3/6/19. It will focus on the modeling work that DRI has completed and presented this morning. Ivo Bergsohn asked if anyone had any key take aways that they would like presented at the workshop. • Sachi Itagaki recommended that it may be good for Shelly Thompsen, Public Affairs Manager-STPUD, to help DRI modify the presentation for Public Outreach. • Robert Reeves suggested that a representative from DDW be present for questions form the public with regards to drinking water concerns where wells will be addressing a plume. This may be new information for the Public. • Discussion was had regarding other organizations that may be able to assist with presenting the information to the General Public. 6) Next Steps 12:45 a) TAC Meeting 4 Action Items (See Attached - Exhibit H) • Sachi Itagaki recapped the action items that KJC will move forward on. • DRI needs to make corrections to their slide presentation before it is distributed. • Ivo Bergsohn conducted a discussion on the requirements for the 3/6 Public Meeting presentation. b) Draft F&T Modeling Report • March 2019. c) Draft Feasibility Study Report • By April, 2019 7) Adjourn 13:00 X:\Projects\General\17W006_So Y FS\4.0 TAC\Mtng 4_Feb 2019\Agenda_17W006_ TAC Proj Mtng 4_26 Feb 2019.docx