D1712508_Final Project Report_6.25.20
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GROUNDWATER GRANT PROGRAM
FINAL REPORT
Grantee: South Tahoe Public Utility District
Title: FEASIBILITY STUDY OF REMEDIAL ALTERNATIVES TO MITIGATE TETRACHLOROETHYLENE
CONTAMINATION
Agreement No.: D1712508
Date: June 25, 2020
Project Type: Planning
Total Project Cost: $1,086,730.00
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Contents
Executive Summary ............................................................................................................................................ 4
Background ........................................................................................................................................................ 6
Problem Statement ........................................................................................................................................ 6
Site Location ................................................................................................................................................... 7
Project Description ............................................................................................................................................. 8
Project Purpose .............................................................................................................................................. 9
Project Scope .................................................................................................................................................. 9
Project Costs ................................................................................................................................................. 11
Project Schedule ........................................................................................................................................... 11
Project Report Narrative .............................................................................................................................. 15
Project Goals ................................................................................................................................................. 15
CEQA/Permitting/Project Methodology ...................................................................................................... 16
Monitoring and Reporting ............................................................................................................................ 16
Monitoring Locations ................................................................................................................................... 18
Public Outreach ............................................................................................................................................ 20
Project Evaluation and Effectiveness ............................................................................................................... 20
Project Performance Measures .................................................................................................................... 21
Conclusions ...................................................................................................................................................... 24
Lessons Learned ........................................................................................................................................... 24
References ........................................................................................................................................................ 26
Appendix A - List of Deliverables ..................................................................................................................... 27
Exhibit A – Progress Report Narrative .......................................................................................................... 30
Appendix B - Photographs ................................................................................................................................ 42
Pre-Design Investigation Photo Monitoring: Pre-Implementation .............................................................. 42
Pre-Design Investigation Photo Monitoring: Implementation..................................................................... 45
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Pre-Design Investigation Photo Monitoring: Post - Implementation .......................................................... 58
Appendix C – Supporting Data, Tables, Graphs, or Figures ............................................................................. 61
GENERAL ....................................................................................................................................................... 61
PRE-DESIGN INVESTIGATION ........................................................................................................................ 63
GROUNDWATER FATE AND TRANSPORT MODELING .................................................................................. 92
FEASIBILITY STUDY REPORT ........................................................................................................................ 110
INTERIM REMEDIAL ACTION PLAN ............................................................................................................. 123
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Executive Summary
On March 29, 2018, Grant Agreement D1712508 was entered into by the South Tahoe Public Utility District
(District) and the State Water Resources Control Board (SWRCB) with the purpose of conducting a Pre-
Design Investigation (PDI) and Feasibility Study (FS) to evaluate whether existing and/or new wells can be
used to provide hydraulic control and removal of tetrachloroethylene (PCE) from groundwater in the South
Lake Tahoe basin, designated by the California Department of Water Resources (DWR) as the Tahoe South
Subbasin of the Tahoe Valley Groundwater Basin (Basin Number 6-005.01). The scope of work for this
project is detailed in Agreement D1712508, Exhibit A- Scope of Work.
PCE has been detected in in private and public drinking water wells in the South Y area of South Lake
Tahoe, California since 1989, when this contaminant was first required to be tested in public drinking water
wells. The South Y is a local reference named for the intersection of U.S. Route 50 and State Highway 89 in
the north-central portion of the Tahoe South Subbasin (herein referred to as the TVS Basin). PCE
groundwater contamination detected in these wells is believed to have resulted from spills and releases
associated with the use of commercial grade dry cleaning solvents in the South Y area during the mid to
late 1970’s.
Groundwater is the primary source of drinking water in the TVS Basin. Since 1989, PCE contamination has
impaired public water supply wells situated within the service areas of the: District; Lukins Brothers Water
Company (LBWC); and Tahoe Keys Water Company (TKWC). Currently, PCE groundwater contamination is
impairing water quality in five public water-supply wells and threatens another well located at the north
end of the plume near the plume front. The impairment of water quality in drinking water wells affects the
ability to use these wells for drinking water supply. When just considering the impairment to public water
system wells, it is estimated that nearly 4 million gallons per day of water production is being lost due to
change in operating status (from active to inactive) or wellhead treatment system capacity limitations.
The PDI was used to collect specific capacity, aquifer characterization and water quality data that can be
used to design strategies for the purpose of hydraulic control and/or removal of PCE contamination from
groundwater. To meet these objectives, the PDI involved the drilling, installation, sampling, and pump
testing of a new test well, for lithologic description, aquifer characterization, and vertical delineation of PCE
contamination. The PDI included sampling and monitoring of existing wells neighboring the test well to
calculate aquifer hydraulic properties; identify groundwater contaminant pathways; determine horizontal
and vertical hydraulic gradients; and groundwater flow directions. Findings of this groundwater
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investigation are presented in the PDI Final Report (Kennedy Jenks, 2019b) and were used to help inform
the FS.
The FS was performed to: identify a suite of potential alternatives, in coordination with a joint Technical
Advisory Committee (TAC) and Stakeholders Advisory Group (SAG); evaluate these alternatives for
effectiveness, implementability, environmental effects and cost; and select an alternative that best met the
remedial action objectives (RAOs) and complied with the applicable or relevant and appropriate
requirements (ARARs) identified in the FS Workplan (Kennedy Jenks, 2018a). A FS Report (Kennedy Jenks,
2020d) describing the activities performed for the development and evaluation of remedial alternatives
was completed in accordance with the scope of work.
As part of the FS, a screening-level Human Health Risk Assessment (HHRA) was performed to consider risks
with PCE contaminated groundwater at public drinking water supply wells in the South Y area and a Human
Health Risk Assessment Report (Kennedy Jenks, 2019a) was completed. In addition to the HHRA, a
Groundwater Fate and Transport Model was developed to help advance and evaluate potential alternatives
considered in the FS in terms of effectiveness with respect to: PCE mass removal; and short- and long-term
reductions in PCE concentration trends. The Groundwater Fate and Transport Model and the analysis used
to evaluate modeled alternatives are described in the Fate and Transport Modeling Report (Desert
Research Institute, 2019a) and the Fate and Transport Modeling Report Addendum (Desert Research
Institute, 2019b).
The FS was used to select a preferred interim remedial alternative. Based on the FS, an Interim Remedial
Action Plan (IRAP) was developed to describe the activities that would lead to implementation of the
selected remedial alternative. Following TAC/SAG review, the District solicited comment on both the FS
Report (Kennedy Jenks, 2020a) and Public Draft IRAP (Kennedy Jenks, 2020b). Following receipt of
comments, an Interim Remedial Action Responsiveness Summary (South Tahoe Public Utility District, 2020)
was prepared addressing public comments on the FS and IRAP reports.
Outreach materials including press releases, fact sheets and presentation materials were developed for five
public workshops and one public webinar convened for the project. Copies of technical reports completed
for the project were posted on the District’s web site.
All project goals were met and the project was completed within budget and schedule.
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Table 1. Comparison table of proposed and actual project.
Grant Agreement Description Actually Accomplished
Conduct a pre-design investigation (PDI) and
feasibility study (FS) to evaluate whether existing
and/or new wells can be used to provide hydraulic
control and removal of tetrachloroethylene from
groundwater in the South Lake Tahoe basin.
• Satisfied Project Management requirements
• Satisfied General Compliance requirements
• Obtained permits, access agreements
• Established a joint TAC/SAG
• Prepared a PDI Workplan
• Prepared a PDI Report
• Prepared a HHRA
• Prepared a FS Workplan
• Developed a Groundwater Fate and
Transport Model
• Prepared a Groundwater Fate and
Transport Modeling Report and Addendum
• Prepared a FS Report
• Prepared an IRAP
• Prepared a Responsiveness Summary
• Prepared CEQA and TRPA environmental
checklists
• Conducted Public Outreach
Background
Problem Statement
PCE has been detected in in private and public drinking water wells in the South Y area of South Lake
Tahoe, California since 1989, when this contaminant was first required to be tested in public drinking water
wells. PCE groundwater contamination found in these wells is believed to have resulted from spills and
releases associated with the use of commercial grade dry cleaning solvents in the South Y area during the
mid to late 1970’s. Since 1989, PCE contamination has impaired water quality in public water supply wells
situated within the service areas of the District, LBWC and TKWC. Currently, PCE groundwater
contamination is impairing water quality in five public water-supply wells and threatens another public
supply well located at the north end of the plume near the plume front. The impairment of water quality in
drinking water wells affects the ability of the affected water companies to use these wells for drinking
water supply. When just considering the impairment to public water system wells, it is estimated that
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nearly 4 million gallons per day of water production is being lost due to change in operating status (from
active to inactive) or wellhead treatment system capacity limitations.
Site Location
The South Y is a local reference named for the intersection of U.S. Route 50 and State Highway 89 in the
north-central portion of the TVS Basin. Figure 1 is a plume map showing the inferred extent of the South Y
Plume based on the findings of the 2019 Regional PCE Groundwater Investigation conducted by the
Lahontan Regional Water Quality Control Board (LRWQCB). The South Y Plume is a groundwater plume
characterized by high concentrations of dissolved PCE contamination, above maximum contaminant levels
[5 micrograms per liter (µg/L)], generally located between the South Y and the Tahoe Keys Lagoon. The
project site location and locations of public water supply wells and existing monitoring wells used for data
collection during the PDI are also shown on Figure 1.
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Figure 1. Area map of the project site.
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Project Description
Project Purpose
The overall purpose of the project is to conduct a PDI and complete a FS to evaluate whether existing
and/or new wells can be used to provide hydraulic control and removal of PCE from groundwater. Criteria
used during the FS for remedial alternatives evaluation included effectiveness, implementability,
environmental effects and cost. The FS was used to select a preferred interim remedial action from which
an IRAP was prepared for possible implementation.
Project Scope
The project is a planning study supported using funds received through a Proposition 1 Groundwater
Planning Grant. The project scope is presented in Agreement D1712508 Exhibit A –Scope of Work and
entailed:
• Conduct Project Management needed for project completion including: technical and administrative
services; Grant Manager notifications; maintaining project schedule(s); conducting site visits; and
conducting photo-documentation of site activities.
• Conduct General Compliance needed to establish project performance and effectiveness including:
obtaining survey data; preparing a Monitoring and Reporting Plan (MRP);preparing a Monitoring
Plan (MP); preparing a Quality Assurance Project Plan (QAPP); and uploading groundwater analytical
data to GeoTracker.
• Obtaining all permits and access agreements required for conducting the field investigation.
• Establish a Technical Advisory Group (TAC) consisting of representatives from the Division of
Financial Assistance (SWRCB-DFA), the Division of Drinking Water (SWRCB-DDW) and Lahontan
Regional Water Quality Control Board (LRWQCB); and conduct meetings with these representatives
to discuss technical issues and review technical materials developed during the project.
• Establish a Stakeholders Advisory Group (SAG) of interested parties and conduct meetings to inform
and solicit input on project activities.
• Develop and execute a Memorandum of Understanding (MOU) with the SWRCB and LRWQCB.
• Prepare a Pre-Design Investigation (PDI) Workplan presenting the project objectives, describing the
project site and field work activities proposed for the site investigation.
• Prepare a Pre-Design Investigation (PDI) Report including a summary of the project areas site
history, field work activities, findings of the investigations and recommendations for future work.
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• Prepare a Human Health Risk Assessment (HHRA) to identify threats to human health as a result of
potential exposure to contaminated groundwater.
• Prepare a Feasibility Study (FS) Workplan to describe the objectives for the FS, including remedial
action objectives (RAOs) and applicable or relevant and appropriate requirement (ARAR) analyses.
• Develop a Groundwater Fate and Transport Model to evaluate potential remedial alternatives.
• Prepare a Groundwater Fate and Transport Modeling Report describing the model, modeling
activities and findings of the modeling evaluation conducted in support of the FS.
• Prepare a Feasibility Study (FS) Report including a summary of the project site area, the nature and
extent of contamination, RAOs, HHRA, RAO analyses, life-cycle costs and process and selection of a
preferred remedial alternative.
• Prepare an Interim Remedial Action Plan (IRAP) based on the FS describing activities required for
implementation of the preferred remedial alternative.
• Prepare a Responsiveness Summary describing the process used for solicitation of public comments,
comments received during the public comment period and responses to comments received on the
FS Report and IRAP.
• Prepared initial documentation required under the California Environmental Quality Act (CEQA)
including CEQA – Initial Study and local Tahoe Regional Planning Agency (TRPA) environmental
checklists.
• Develop Public Outreach materials and conduct public workshops to inform the public and receive
comment during the project.
The scope of the project does not include the investigation, assessment or clean-up of potential source
area sites. This work is being addressed by other parties outside this scope under orders issued by the
LRWQCB.
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Project Costs
The budget for the work within Agreement D1712508 was $1,086,730 which included $543,365 grant and
$543,365 in local match funds (Table 2). This is the Final Budget Summary after a Deviation Request on
November 15, 2019. The Deviation Request was needed for extra work required to satisfy the purpose of
Agreement D1712508 that were not anticipated in the original scope of work. The Deviation Request was
approved on March 9, 2020, which increased total project costs by $78,140; $39,070 in additional grant
funds and $39,070 in STPUD match funds.
Table 2. Budget Summary.
Proposition 1 GROUNDWATER GRANT PROGRAM -
BUDGET SUMMARY
Budget Category Grant Funds Local Match
Funds Total % Local
Match
1. Project Administration $36,224 $ 38,634 $74,858 52%
2.
Planning/Design/Engineering/
Environmental
$457,614 $466,896 $924,510
51%
3.
Construction/Implementation
$0 $0 $0 0%
4. Monitoring/Performance $0 $28,664 $28,664 100%
5. Education/Outreach $49,527 $9,171 $58,698 16%
Grand Total: $543,365 $543,365 $1,086730 50%
Project Schedule
Table 3 is the Submittal Schedule for Agreement D1712508. Strikethroughs in the Estimated Due Dates are
used to show the schedule changes approved by three amendments to the Agreement during the project.
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The original work completion date was March 31, 2019. In January 2019, the Agreement was amended
(Amendment 1) changing the work completion date to June 30 2019. Need for additional time to complete
the project is described in the Request for Time Extension dated 9/13/2018. Tasks requiring additional time
included: Task 8 Pre-Design Investigation involving additional time needed to: confer with the TAC to
decide on construction of an additional test well to prevent vertical cross contamination; construct a
second test well; and obtain pump test and laboratory information used to inform the feasibility study
(Task 12).
In July 2019, the Agreement was amended a second time (Amendment 2) changing the work completion
date to January 31, 2020. Need for additional time to complete the project is described in the Request for
Time Extension dated 5/10/2019. Tasks requiring additional time included: Task 4 Technical Advisory
Committee and Task 5 Stakeholders Advisory Group: technical review and comment of project submittals;
Task 11.1 Groundwater Fate and Transport Modeling: model recalibration used to incorporate new
information developed during the Pre-design Investigation, and fate and transport model evaluation of
remedial alternative scenarios; and Task 12 Feasibility Study: development and evaluation of interim
remedial alternatives.
In March 2020, the Agreement was amended a third time (Amendment 3) changing the work completion
date to June 30, 2020. Need for additional time to complete the project is described in the Request for
Time Extension dated 11/01/2019. Tasks requiring additional time included Task 1 Project Management:
updating project schedules and time extension requests; Task 4 Technical Advisory Committee and Task 5
Stakeholders Advisory Group: additional meetings required to communicate and solicit input on additional
analysis conducted for the Pre-Design Investigation, Groundwater Fate and Transport Model and Feasibility
Study Report; and Task 15 Public Outreach: time for additional public workshops conducted during the
project.
Table3. Project Schedule
ITEM DESCRIPTION OF SUBMITTAL CRITICAL DUE DATE ESTIMATED DUE DATE
EXHIBIT A-3 PROJECT-SPECIFIC SCOPE OF WORK
1. Project Management
1.2 Notification of Upcoming Meetings, Workshops, and Trainings 15 Working Days Prior
1.3 Detailed Project Schedule 60 Days After Execution Complete
1.4 Periodic and Final Site Visits As Needed
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ITEM DESCRIPTION OF SUBMITTAL CRITICAL DUE DATE ESTIMATED DUE DATE
1.5 Pre-, During, and Post-Implementation Photos Ongoing
2. General Compliance Requirements/Project Effectiveness and Performance
2.1 GPS Information 60 Days After Well Installation Complete
2.2 Monitoring and reporting Plan (MRP) May 2018 Complete
2.2.2 Quality Assurance Project Plan (QAPP) May 2018 Complete
3. Permitting
3.1 List of Approvals, Entitlements or Permits May 2018 Complete
4. Technical Advisory Committee (TAC)
4.1 List of TAC Members, with Roles and Responsibilities, and Affiliations
30 Days After Execution Complete
4.2 Summary of Kickoff Meeting May 2018 Complete
4.3 Agendas, Meeting Minutes, and Sign-In Sheets Ongoing
5. Stakeholder Advisory Group (SAG)
5.1 List of SAG Members May 2018 Complete
5.2.1 Meetings Schedule 30 Days After Execution Complete
5.2.2 Meetings Materials, Summary of Feedback and Comments, and Sign-In Sheet(s) Ongoing
EXHIBIT A-3 PROJECT-SPECIFIC SCOPE OF WORK
6. Memorandum of Understanding (MOU)
6.1 Executed MOU
60 Days After Execution January 31, 2019 November 30, 2019
Removed in Amendment 3
6. Pre-Design Investigation Workplan
6.1 Pre-Design Investigation Workplan 60 Days After Execution Complete
7. Pre-Design Investigation and Reporting
7.1.1 Well Completion Report May 2018 Complete 7.1.4 Proposed Changes from Approved Workplan May 2018
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ITEM DESCRIPTION OF SUBMITTAL CRITICAL DUE DATE ESTIMATED DUE DATE
Complete
7.2 Pre-Design Investigation Report
May 2018 January 2019
August 2019 Complete
8. Baseline Human Health Risk Assessment
8.1 Baseline Human Health Risk Assessment Report May 2018 January 2019
Complete
9. Feasibility Study Workplan
9.1 Feasibility Study Workplan May 31, 2018 Complete
10. Groundwater Fate and Transport Modeling
10.2 Draft Fate and Transport Modeling Report
June 2018
February 2019 July 2019
Complete
10.3 Final Fate and Transport Modeling Report
July 2018 March 2019
August 2019 Complete
11. Feasibility Study and Report
11.2 Feasibility Study Report
September 2018 April 2019
September 2019 March 2020
12. Interim Remedial Action Plan
12.3.1 Interim Remedial Action Plan
November 2018
June 2019 October 2019
January 2020
13. Environmental Compliance
13.1.1 Draft Initial Study Checklist
August 2018
March 2019 August 2019
December 2019
EXHIBIT A-3 PROJECT-SPECIFIC SCOPE OF WORK
13.1.2 Final Initial Study Checklist
September 2018 April 2019
September 2019 February 2020
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ITEM DESCRIPTION OF SUBMITTAL CRITICAL DUE DATE ESTIMATED DUE DATE
14. Public Outreach
14.1 Outreach Materials and Web Links
November 2018
April 2019 October 2019 February 2020
14.2 Workshop Materials, Sign-In Sheets, and Photo Documentation November 2018 October 2019
February 2020
EXHIBIT A-5 REPORTING
(a) Progress Reports Quarterly
(b) As Needed Information or Reports As Needed
(c) Final Reports
(c)(1) Draft Final Project Report January 31,2019
April 30, 2019 November 30, 2019 April 30, 2020
(c)(2) Final Project Report February 28, 2019 May 30, 2019 December 31, 2019 May 31, 2020
(c)(3) Final Project Summary Before Work
Completion Date
EXHIBIT B – FUNDING PROVISIONS
4 (b) Final Disbursement Request April 30, 2019 July 31, 2019 February 29,2020 July 31,2020
9 (b)(4) Disbursement Requests Quarterly
Project Report Narrative
The progress report narrative is a summary of the project activities conducted from the start of the project
through the work completion date. The project report narrative for Agreement D1712508 is presented as
Exhibit A in Appendix A.
Project Goals
The District was able to develop and evaluate remedial alternatives to provide hydraulic control and
removal of PCE from groundwater that are adversely affecting the beneficial use of groundwater in the
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South Y area and select a preferred remedial action to address such contamination. Major goals attained
during the project included;
• Pre-Design Investigation for the collection of specific capacity, aquifer characterization and water
quality data used to design strategies for the purpose of hydraulic control and/or removal of PCE
contamination from groundwater.
• Groundwater Fate and Transport Model of the South Y Area for the development and evaluation of
interim remedial alternatives for the purpose of hydraulic control and/or removal of PCE
contamination from groundwater.
• Feasibility Study for the evaluation and selection of a preferred remedial alternative for the purpose
of hydraulic control and/or removal of PCE contamination from groundwater;
• Interim Remedial Action Plan for implementation of the selected interim remedial action; and
• Public Outreach to engage the public during the course of the project.
CEQA/Permitting/Project Methodology
A Notice of Exemption (NOE) for performance of the PDI was prepared and filed with the County Clerk,
County of El Dorado on March 5, 2018. The NOE was posted by the County Clerk from March 6, 2018
through April 9, 2018.
During the second quarter of 2019 environmental checklists (CEQA Appendix G; and TRPA Initial
Environmental Checklist) and project descriptions were prepared for Alternative 3 and submitted to the
Project Director for initial review. These checklists and project descriptions were refined and further
developed during the FS.
The final environmental checklists (CEQA Appendix G; and TRPA Initial Environmental Checklist) were
completed and submitted to the TAC/SAG for review and comment on February 18, 2020. The final
environmental checklists for the preferred interim remedial alternative (Alternative 2) are presented in
Appendix C of the final FS Report (Kennedy Jenks, 2020d).
Monitoring and Reporting
Monitoring and reporting for this project involved the collection and evaluation of groundwater quality and
groundwater level elevation data that can be used to design strategies for the purpose of hydraulic control
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and/or removal of PCE contamination from groundwater. These data were generated through the conduct
of a Pre-Design Investigation (PDI) developed for the FS. The objectives of the PDI were to:
• Characterize the range of contamination within the PDI Project Site;
• Determine the vertical extent and distribution of PCE contamination in groundwater to a total depth
of 150 feet;
• Design and construct a test well for aquifer pump testing;
• Conduct an aquifer pump test to estimate hydraulic characteristics of the aquifer;
• Evaluate aquifer characteristics to estimate well yield and long-term pumping suitability to achieve
mass removal and PCE plume capture;
• Provide water quality data required to complete a pre-design of a potential future extraction well
and accompanying treatment system; and
• Provide groundwater level data to establish groundwater gradients and flow directions.
The project Monitoring Plan is integrated into the South Y Pre-Design Investigation Workplan [Agreement
D1712508] (Kennedy Jenks, 2018a). Section 1 of the Workplan includes the statement of objectives;
background information, including the site description, site history, and previous investigations, project
organization, responsibilities and field investigation schedule. Section 2.0 of the Workplan presents the
sampling and analysis plan, outlining the field investigation, the objective of each phase of work, and the
sampling and analysis activities to be completed. Field procedures including decontamination procedures
are presented in Section 3.0; while procedures for the handling, waste characterization and disposal of
investigation-derived wastes are described in Section 4.0. Section 5.0 of the Workplan is the Quality
Assurance Project Plan (QAPP) specifying the procedures to be followed to maintain field and laboratory
data of consistent quality.
During the development of the Workplan existing monitoring wells were located for Baseline Sampling.
Baseline Sampling involved the collection of groundwater samples for analysis of Volatile Organic
Compounds (VOCs) from eight monitoring wells neighboring the PDI Project Site (MW-4A, MW-4B, MW-4C,
MW-7C, MW-7D, MW-10B, MW-10C, and EW-4D). These wells were selected based on site proximity, well
construction and past detection of PCE contamination. Analytical results from the Baseline Sampling were
used to show the distribution of PCE contamination in groundwater neighboring the PDI Project Site at the
time of the site investigation.
During the site investigation , groundwater samples were collected during zone testing of the Test Hole;
and during time-series sampling of the pumping well (EW-1C) used for the constant rate test. Analytical
results from the zone testing were used to show the vertical extent and distribution of PCE contamination
at the PDI Project Site. Analytical results from the time-series sampling was used to monitor potential
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changes in VOC contaminant concentrations and calculate contaminant mass extraction rates for PCE,
trichloroethylene(TCE), and dichloroethylene(DCE) at the pumping well. Groundwater level readings were
collected using dedicated data loggers during aquifer testing from the two test wells installed as part of the
site investigation (EW-1B, EW-1C), and from four other existing monitoring wells (MW-4A, MW-4B, MW-4C
and MW-XA) used as observation wells during the constant rate test. The water level data was evaluated to
estimate aquifer properties.
Groundwater level elevation readings were collected from more than twenty (20) wells within and
neighboring the South Y Area. The locations of the wells used for groundwater level elevation readings are
shown on Figure 1. Coordinates and elevations for all wells used for data collection are provided in Table 4.
Groundwater level measurements from these wells were used to show fall (seasonal low) and spring
(seasonal high) groundwater conditions, generate groundwater-level elevation contours, calculate average
horizontal gradients and groundwater flow directions for three different water-bearing zones impacted by
the South Y Plume. Groundwater level readings collected from four well clusters, (Clement Well, MW-4,
MW-7 and MW-10) were used to calculate vertical gradients through the South Y Area.
Subsurface, PCE contaminant distribution, and hydrologic information developed during the PDI are
presented in the Pre Design Investigation Report for Remedial Alternatives to Mitigate Tetrachloroethylene
Contamination (D1712508) (Kennedy Jenks, 2019b). Data and findings from this investigation were used to:
calculate aquifer properties, horizontal and vertical groundwater gradients, groundwater velocities, travel
times and advective flux density rates; and refine the Groundwater Fate and Transport Model. Capture
zone analysis completed during the PDI was used in the FS to help develop strategies for the purposes of
hydraulic control and/or removal of PCE contamination from groundwater. A well survey was conducted to
identify private wells in the South Y Area susceptible to groundwater contamination and potential vertical
conduits for PCE contaminant distribution.
Monitoring Locations
The PDI Project Site is located on a 1.10-acre parcel (APN 023-30-109) owned by the City of South Lake
Tahoe (CSLT) at 953 Eloise Avenue (see Figure 1). The site is used for a CSLT Storm Water Retention Basin
located in the northeast corner of the intersection of Eloise Avenue and 5th Street, in South Lake Tahoe,
CA. Surveyed coordinates and elevations of wells used for data collection during the PDI are listed below in
Table 4.
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Table4. Coordinates and elevations of wells used for data collection
Well Latitude
(WGS 83)
Longitude
(WGS 83)
Ground
Elevation
(NAVD88)
Measuring
Point
Elevation
(NAVD88) Water Quality Ground-water Levels Well
Type1
Industrial Well #2 38.902449438 -120.008395941 6306.45 6306.82 X OW
Tata Well #2 38.907481254 -120.005490107 6284.11 6286.09 X OW
Clement Well 38.912852683 -120.011292816 6281.28 6282.58 X PWS
CL-1 38.912885860 -120.010971269 6278.76 6278.12 X MW
CL-3 38.912903503 -120.011005419 6278.64 6278.34 X MW
MW-4B 38.916519830 -120.005429700 6259.52 6259.27 X X MW
MW-4A 38.916520490 -120.005429800 6259.36 6259.11 X X MW
MW-4C 38.916525830 -120.005436600 6259.81 6259.56 X X MW
EW-1B 38.916784470 -120.005310300 6260.37 6262.24 X X PDI
EW-1C 38.916789890 -120.005288400 6260.62 6262.48 X X PDI
EW-4C 38.917365750 -120.006887200 6265.04 6265.04 X MW
EW-4D 38.917373260 -120.006902400 6265.24 6264.99 X X MW
MW-10A 38.917693980 -120.007490200 6264.89 6264.54 X X MW
MW-10B 38.917694690 -120.007491100 6264.93 6264.43 X X MW
MW-10C 38.917704640 -120.007509500 6264.96 6264.56 X X MW
Helen Well #2 38.918874528 -119.993137907 6248.83 6250.18 X PWS
MW-7D 38.919209270 -120.007885600 6255.05 6254.65 X X MW
MW-7C 38.919214700 -120.007895100 6254.88 6254.53 X X MW
LBWC 4 38.920418450 -120.008375700 6249.38 6249.78 X PWS
LBWC 1 38.922971830 -120.022389400 6261.11 6261.44 X PWS
LBWC 2 38.924859110 -120.013962300 6250.00 6251.45 X PWS
LBWC 5 38.924939460 -120.013965100 6248.77 6250.77 X PWS
TKWC 2 38.928027560 -120.011614800 6235.77 6237.87 X PWS
TKWC 3 38.930220760 -120.022484200 6235.79 6238.79 X PWS
TKWC 1 38.933095420 -120.004574700 6236.68 6238.18 X PWS
Notes:
1) Well Type: OW- Observation Well (existing); PWS- Public Water System Well (existing); MW-
Monitoring Well (existing); PDI- Pre-Design Investigation Test Well (installed).
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Public Outreach
During the term of this Prop 1 Groundwater Planning Grant, Public Outreach activities for the South Y
Feasibility Study included:
• Preparation of FACT SHEET: Groundwater Contamination at South Lake Tahoe Y Area and Media
Releases for public notification and posting on the District’s website;
• Preparation of workshop materials including agendas, sign-in sheets and technical presentations;
• Five (5) Workshops to inform the public throughout the progress of the South Y Feasibility Study,
convened at the CSLT Council Chambers on February 7, 2018 (PW1), August 8, 2018 (PW2),
November 7, 2018 (PW3), March 6 2019 (PW4) and June 26, 2019 (PW5) with live-streaming
available through the CSLT website;
• Publication of a Notice of Availability (NOA) in the March 20, 2020 edition of the Tahoe Daily
Tribune announcing a 30-day public comment period, availability of the draft IRAP and FS Report,
and a March 31, 2020 webinar presenting the draft IRAP;
• Presentation of the draft IRAP during a webinar on March 31, 2020; and
• Posting of all final technical documents and recordings of public workshops and meetings
completed for this project on the District’s web site.
Project Evaluation and Effectiveness
Project goals for Agreement D1712508 included the following:
• Prepare a Monitoring and Reporting Plan that includes information necessary to determine the
suitability of using domestic supply as remediation wells for plume containment and removal of
PCE from groundwater.
• Obtain all public agency approvals, entitlements or permits required for the Project.
• Establish a Technical Advisory Committee (TAC)
• Establish a Stakeholder Advisory Group (SAG) that consists of interested parties
• Develop and execute a Memorandum of Understanding (MOU)
• Prepare a Pre-Design Investigation Workplan
• Conduct a Pre-Design investigation in the project area
• Prepare a Pre-design Investigation Report
• Prepare a Baseline Human Health Risk Assessment (HHRA)
• Prepare a Feasibility Study Workplan
• Conduct Groundwater Fate and Transport Modeling
21
• Conduct a Feasibility Study
• Prepare a Feasibility Study Report
• Develop an Interim Remedial Action Plan
• Initiate documentation required under CEQA
• Conduct Public Outreach
Project Performance Measures
Table 5 describes the goals, measurement tools and methods and targets used for the project. Attainment
of project goals is demonstrated by the deliverables described in the Actual column at the far right of the
table.
Table 5. Project Performance Measures
Project Performance Measures
Project Goals Measurement Tools
and Methods Targets Actual
Prepare a Monitoring and
Reporting Plan that includes
information necessary to
determine the suitability of
using domestic supply as
remediation wells for plume
containment and removal of
PCE from groundwater..
Analyze previously collected
groundwater data. Prepare and
implement a Workplan
including a Sampling Plan and
Quality Insurance Project Plan
(QAPP).
Provide pre-design data needed
for preliminary design of
remediation wells, develop
groundwater clean-up
alternatives and identify data
gaps.
Provided pre-design data
needed for preliminary design
of remediation wells,
developed groundwater clean-
up alternatives and identified
data gaps.
Obtain all public agency
approvals, entitlements or
permits required for the
Project.
Prepare a list of all public
agency approvals, entitlements
or permits attained for the
Project.
Provide a list of all public
agency approvals, entitlements
or permits attained for the
Project to the Grant Manager.
Provided a list of all public
agency approvals, entitlements
or permits attained for the
Project to the Grant Manager.
Establish a Technical Advisory
Committee (TAC)
Convene a kickoff meeting to
establish TAC goals and
objectives, formalize roles, and create a schedule for future
meetings.
Conducted additional TAC
meetings in accordance with the schedule developed to
review and comment on grant deliverables
Convened a Joint TAC/SAG
Committee. Conducted
additional Joint TAC/SAG meetings on a quarterly basis as
dictated by the needs and progress of the FS to review and comment on grant deliverables.
22
Project Goals Measurement Tools
and Methods Targets Actual
Establish a Stakeholder Advisory Group (SAG) that consists of interested parties.
Conduct SAG meetings to inform members of Project activities and solicit feedback and comments.
Meet with SAG members,
inform members of Project
activities and provide a
summary of feedback and
comments received, and sign- in
sheets to the Grant Manager.
Convened a Joint TAC/SAG Committee. Conducted additional Joint TAC/SAG meetings on a quarterly basis as dictated by the needs and progress of the FS to review and comment on grant deliverables
Develop and execute a Memorandum of Understanding (MOU) with the SWRCB and LRWQCB
Develop a draft MOU for review
and consideration by the
SWRCB and LRWQCB
Developed a draft MOU for
review and consideration by the
SWRCB and LRWQCB
A Final MOU was developed for
the project. Requirement for
execution of the MOU was
removed by Amendment 3 of
the Agreement.
Prepare a Pre-Design Investigation Workplan and submit to the TAC for comment and Grant Manager for approval.
Review previously collected geologic, hydrologic and groundwater quality data. Develop technical approach to achieve project objectives and prepare a Pre-Design Investigation Workplan
Submitted Pre-Design Investigation Workplan to the Joint TAC/SAG for comment and Grant Manager for approval
A final Pre-Design Investigation
Workplan was prepared and
approved by the Grant
Manager.
Conduct a Pre-Design
Investigation in the Project
Area in accordance with the
approved Pre-Design
Investigation Workplan
Conduct periodic site visit and
perform pre-during and post
photo monitoring.
Meet with Joint TAC/SAG
members, inform members of
Pre-Design Investigation
activities.
Conducted periodic site visits,
and performed pre-during and
post photo monitoring.
Conducted site visits(s) with
Grant Manager and submitted
pre-during and post photo
monitoring approved by the
Grant Manager
Prepare a Pre-Design
Investigation Report and submit
to the TAC for comment and
Grant Manager for approval.
Prepare a summary of project
area’s site history and field
work activities. Compile, review
and evaluate the collected data.
Prepare investigation findings
and conclusions.
Submitted Pre-Design
Investigation Report to the
Joint TAC/SAG for comment
and Grant Manager for
approval
A final Pre-Design Report was
prepared and approved by the
Grant Manager.
Prepare a Baseline Human
Health Risk Assessment that
identifies threats to human
health as a result of potential
exposure to contaminant
groundwater in the project
area.
Reviewed pertinent site and PCE contamination data.
Evaluate data and perform screening level human health risk assessment. Perform
exposure and toxicity assessments and risk characterization.
Submitted Human Health Risk Assessment Report to the Joint TAC/SAG for comment and
Grant Manager for approval
A final Human Health Risk Assessment Report was prepared and approved by the
Grant Manager.
23
Project Goals Measurement Tools
and Methods Targets Actual
Prepare a Feasibility Study Workplan and submit to the TAC for comment and Grant Manager for approval.
Develop steps to conduct the Feasibility Study. Identify and define remedial action objectives. Identify applicable or relevant and appropriate requirements.
Submitted Feasibility Study Workplan to the Joint TAC/SAG for comment and Grant Manager for approval
A final Feasibility Study Workplan was prepared and approved by the Grant Manager.
Conduct Groundwater Fate and
Transport Modeling for the
purposes of evaluation
potential implementation
projects that will prevent or
clean-up groundwater
contamination.
Define model boundary
conditions and transport
parameters for project area.
Develop steady-state and
transient Groundwater Fate
and Transport Model. Perform
fate and transport model
calibration. Develop fate and
transport simulations for
potential implementation
projects. Review and evaluate
Fate and Transport model
results.
Meet with Joint TAC/SAG
members, inform members of
Groundwater Fate and
Transport Modeling activities.
Submitted Groundwater Fate
and Transport Modeling Report
to the Joint TAC/SAG for
comment and Grant Manager
for approval
A final Feasibility Study Workplan was prepared and approved by the Grant Manager.
Conduct a Feasibility Study in
accordance with the approved Feasibility Study Workplan
Perform data review and conduct Feasibility Study kick-
off. Develop screening criteria, review and refine modeled
alternatives for engineering evaluation. Develop life-cycle cost estimates. Rank remedial
alternatives and select a preferred interim remedial
alternative. Further develop
preferred alternative.
Meet with Joint TAC/SAG
members, inform members of Feasibility Study activities.
Submitted Feasibility Study
Report to the Joint TAC/SAG for
comment and Grant Manager
for approval
A final Feasibility Study Report
was prepared and approved by the Grant Manager.
Develop an Interim Remedial
Action Plan (IRAP) for the preferred alternative selected by the Feasibility Study
Identify implementation
activities associated with the preferred alternative including
potential agreements, funding
sources, plans and permits needed for implementation.
Develop an implementation schedule. Circulate the draft IRAP to the SAG and interested parties for comment, incorporate comments and prepare an Interim Remedial Action Responsiveness Summary.
Meet with Joint TAC/SAG
members, inform members of
Interim Remedial Action Plan
activities.
Submit draft IRAP to Joint
TAC/SAG members, for
comment.
Notify interested parties and
circulate approved draft IRAP
for 30-day Public Comment
Period.
A final Interim Remedial Action
Plan and Responsiveness Summary was prepared and approved by the Grant Manager
24
Project Goals Measurement Tools
and Methods Targets Actual
Initiate documentation required under the California
Environmental Quality Act
(CEQA) for the proposed
implementation project.
Complete CEQA Appendix G
Environmental Checklist and
Tahoe Regional Planning
Agency (TRPA Initial
Environmental Checklist for
Determination of
Environmental Impact for the
Interim Remedial Action.
Submit draft Environmental
Checklists to Joint TAC/SAG members, for comment.
Draft Environmental Checklists for the Interim Remedial Action
are included in the Feasibility Study Report approved by the
Grant Manager.
Conduct Public Outreach
Develop outreach materials, update the District’s website to include project progress and outcomes and conduct at least one public workshop prior to finalizing the Feasibility Study Report and Interim Remedial Action Plan.
Developed outreach materials, updated the District’s website to include project progress and outcomes and convened five public workshop and one webinar prior to finalizing the Feasibility Study Report and Interim Remedial Action Plan.
Workshop materials were
submitted to the Grant manger.
Workshop recordings are
posted on the District’s website
(http://stpud.us/groundwater/)
Conclusions
The goals of the project were to conduct a Pre-Design Investigation and complete a Feasibility Study to
evaluate whether existing and/or new wells can be used to provide hydraulic control and removal of PCE
from groundwater and use the Feasibility Study to identify and select a preferred interim remedial
alternative and prepare an Interim Remedial Action Plan for a possible implementation project. All project
goals were met and the project was completed within budget and schedule.
Lessons Learned
Lessons learned include ways to be more efficient, working closely with the grant manager and most
importantly allowing more time for reviews with both the TAC and stakeholders.
• Work with the Grant Manager to obtain a draft of the project-specific scope of work to ensure that
the scope of work in the Agreement aligns with the scope of work presented in the technical
proposal and includes expectations of regulatory criteria necessary for alternatives evaluation.
• Work with the Grant Manager to recognize any deviations that would require adjustments to the
project budget and schedule, prior to execution of the Agreement.
25
• Ensure critical due dates in the grant agreement are met. These must go through a formal
schedule extension process, while estimated due date deliverables do not. Any critical due date
items that can be started now, should be started if possible.
• Ensure adequate review time is built into deliverable schedule as the dates on the deliverables
schedule are for the FINAL deliverable. Build in at least 2 weeks of District review and 2 weeks of
comment incorporation/finalization for deliverables going to the TAC. The TAC requires at least 2
weeks of review time, but typically request longer. Additional time (~2 weeks), should be built in
the project schedule to respond to TAC comments and prepare response to comments to close the
loop.
• Identify stakeholder water agency needs to meet and confer with their Board of Directors. Align
the project schedule with Board of Director meeting schedules when critical project options and
recommendations affecting those agencies are being evaluated.
• Always ensure mutual understanding on document review process and comments received from
TAC agencies. When in doubt have a call with the agencies and design/technical team to confirm
mutual understanding.
• Reconsider the Memorandum of Understanding (MOU) requirement for planning projects. If an
MOU approved by both the SWRCB and local RWQCBs cannot be provided to the Grantee, this
requirement should be removed.
• Let the TAC know what type of review is requested in advance. In most cases, it is not a regulatory
review and comments are provided to help guide the program in the right direction.
• It is important to have frequent communication with regulators and get their buy in on carrying
out permitting requirements (e.g., Policy Memo 97-005 requirements).
• Keeping the TAC involved on how the project overall is going seemed to be positive and kept them
engaged. Ensure sufficient time and budget is allocated for project management.
• Setting calendar reminders of when to send drafts of progress reports and invoices for internal
reviews and submittal was effective to stay on schedule.
• Develop outreach materials early in the project and use multiple workshops to inform the public
and potentially affected local agencies. These workshops are important project milestones that
are important opportunities to build community relations and identify public concerns.
26
References
Desert Research Institute, 2019a. Fate and Transport Modeling of the South Y PCE Groundwater
Contamination Plume, South Tahoe Public Utilities District, June 28, 2019.
Desert Research Institute, 2019b. Fate and Transport Modeling of the South Y PCE Groundwater
Contamination Plume - Addendum, South Tahoe Public Utilities District, September 5, 2019.
Kennedy Jenks, 2018a. South Y Predesign Investigation Workplan (Agreement D1712508), March 23, 2018.
Kennedy Jenks, 2018b. South Tahoe Public Utility District Feasibility Study of Remedial Alternatives to
Mitigate Tetrachloroethylene Contamination, Agreement D1712508, Feasibility Study Workplan
November 19, 2018.
Kennedy Jenks, 2019a. Human Health Risk Assessment for South Y Groundwater, January 2, 2019.
Kennedy Jenks, 2019b. Final Pre-Design Investigation Report for Remedial Alternatives to Mitigate
Tetrachloroethylene Contamination (D1712508), July 10, 2019.
Kennedy Jenks, 2020a. South Y PCE Facilities Feasibility Study, (Agreement D1712508), March 17, 2020.
Kennedy Jenks, 2020b. Draft Interim Remedial Action Plan for the South Y PCE Facilities Feasibility Study,
(Agreement D1712508), March 17, 2020.
Kennedy Jenks, 2020c. Interim Remedial Action Plan for the South Y PCE Facilities Feasibility Study,
(Agreement D1712508), May 9, 2020.
Kennedy Jenks, 2020d. South Y PCE Facilities Feasibility Study, (Agreement D1712508), May 10, 2020.
South Tahoe Public Utility District, 2020. Responsiveness Summary for Item 12 Interim Remedial Action
Plan, Feasibility Study of Remedial Alternatives to Mitigate Tetrachloroethylene Contamination
(Agreement D1712508), June 12, 2020.
27
Appendix A - List of Deliverables
Work
Item Description Due Date % Of Work
Complete
Date
Submitted
EXHIBIT
A
A.1.2 Notification of Upcoming Meetings,
Workshops, and Trainings
15 Working
Days Prior 100
1/25/2018
5/4/2018
5/24/2018
6/26/2018
7/3/2018
7/5/2018
7/10/2018
7/12/2018
7/13/2018
7/30/2018
7/31/2018
8/8/2018
10/16/2018
10/23/2018
2/01/2019
3/6/2019
5/28/2019
6/21/2019
10/11/2019
2/11/2020
3/16/2020
A.1.3 Detailed Project Schedule Complete 100
3/27/2018,
4/7/2018,
6/6/2018
(Schedule
Update 1)
9/13/2018
(Schedule
Update 2)
5/17/2019
(Schedule
Update 3)
2/15/2020
(Schedule
Update 5)
A.1.4 Periodic and Final Site Visits Complete 100 6/12/2018,
6/26/2018
28
Work
Item Description Due Date % Of Work
Complete
Date
Submitted
A.1.5 Pre-, During, and Post-Implementation
Photos Complete 100
3/27/2018,
4/7/2018
5/15/2019
A.2.1 GPS Information Complete 100 9/13/2018
A.2.2 Monitoring and Reporting Plan (MRP)
Complete
100
1/24/18,
3/27/18,
4/7/18
A.2.2.2 Quality Assurance Project Plan (QAPP) Complete 100
1/24/18,
3/27/18,
4/7/18
A.3.1 List of Approvals, Entitlements or Permits Complete 100 5/31/2018
A.4.1 List of TAC Members, with Roles and
Responsibilities, and Affiliations Complete 100 1/25/18
5/15/2019
A.4.2 Summary of Kickoff Meeting Complete 100 5/31/2018
A.4.3 Agendas, Meeting Minutes, and Sign-In
Sheets Complete 100
5/7/2018,
8/15/2018
11/14/2018
2/15/2019
5/15/2019
8/08/2019
2/11/2020
5/15/2020
A.5.1 List of SAG Members Complete 100
5/7/2018,
8/15/2018
5/15/2019
A.5.2.1 Meetings Schedule Complete 100
1/24/18,
3/27/18,
4/5/18,
6/5/2018
9/13/2018
A.5.2.2 Meetings Materials, Summary of
Feedback and Comments, and Sign-In Sheet(s) Ongoing 100
5/7/2018,
8/15/2018
11/14/2018
2/15/2019
5/15/2019
8/08/2019
2/11/2020
5/15/2020
A.6.1 Executed MOU (To Be Removed from
Amendment 3) Complete 100 7/13/2018
3/9/2020
B.7.1 Draft Pre-Design Investigation Workplan Complete 100 1/24/18,
29
Work
Item Description Due Date % Of Work
Complete
Date
Submitted
3/27/18
B.7.2 Final Pre-Design Investigation Workplan Complete 100 4/7/18
B.8.1.1 Well Completion Report Complete 100 12/3/2018
B.8.1.4 Proposed Changes from Approved
Workplan Complete 100
6/8/2018
6/12/2018
7/12/2018
B.8.2 Pre-Design Investigation Report Complete 100
1/10/2019
7/20/2019
11/14/2019
B.9.1 Baseline Human Health Risk Assessment
Report Complete 100
11/27/2018
1/2/2019
1/9/2019
B.10.1 Feasibility Study Workplan Complete 100
9/13/2018
11/19/2018
12/3/2018
B.11.1 Draft Fate and Transport Modeling
Report Complete 100 6/13/2019
11/15/2019
B.11.2 Final Fate and Transport Modeling
Report Complete 100 6/28/2019
11/15/2019
B.12.1 Draft Feasibility Study Report February 2020 100 2/19/2020
B.12.2 Final Feasibility Study Report April 2020 100 6/9/2020
B.13.3.1 Interim Remedial Action Plan April 2020 100 6/9/2020
B.14.1.1 Draft Initial Study Checklist August 2019 100 2/19/2020
B.14.1.2 Final Initial Study Checklist March 2020 100 6/9/2020
B.15.1 Outreach Materials and Web Links April 2020 100
11/15/2018
2/14/2019
5/15/2019
8/8/2019
3/16/2020
3/25/2020
B.15.2 Workshop Materials, Sign-In Sheets, and
Photo Documentation February 2020 100
11/15/2018
2/14/2019
5/15/2019
8/8/2019
5/15/2020
EXHIBIT
B G.1 Progress Reports Quarterly 100
6/6/2018,
8/15/2018
11/14/2018
2/15/2019
5/15/2019
30
Work
Item Description Due Date % Of Work
Complete
Date
Submitted
8/8/2019
11/15/2019
2/12/2020
5/15/2020
G.2 Annual Progress Summaries Annually 0
G.3 NRPI Before Final
Invoice N/A
G.4 Draft Project Report April 30, 2020 100 6/19/2020
G.5 Final Project Report May 31,2020 100 6/25/2020
G.6 Final Project Summary June 30, 2020 100 6/25/2020
G.7 Final Project Inspection and Certification Before Final
Invoice 0
Exhibit A – Progress Report Narrative
The summary of activities for the grant tasks included the following activities and deliverables:
Item 1 – Project Management work item is for the administration of the grant and management of the project.
Notifications (A.1.2) The Grant Manager was provided email notifications for the following events and activities:
• PDI Field Work – Aquifer Testing (7/3/2018, 7/5/2018, 7/10/2018, 7/12/2018);
• South Y Fate & Transport Modeling Analysis/Engineering Evaluation Kick-Off Meeting/Joint TAC/SAG
Meeting 2 (6/11/2018);
• Modeling Analysis/Engineering Evaluation Check-In Call (7/30/2018);
• Joint TAC/SAG Meeting 3 (10/16/2018);
• Joint TAC/SAG Meeting 4 (2/26/2019);
• Joint TAC/SAG Meeting 5 (6/21/2019);
• Public Meeting 2 (7/31/2018);
• Public Meeting 3 (10/23/2018);
• Public Meeting 4 (3/6/2019);
• Public Meeting 5 (6/26/2019).
• Joint TAC/SAG Meeting 6 (10/21/2019);
• Joint TAC/SAG Meeting 7 (02/11/2020); and
• Public Meeting 6 (On-line) (03/16/2020)
Project Schedule (A.1.3). Schedules for the Feasibility Study (FS) were developed and presented to the Grant
Manager on 12/20/2017 (Check-in Call); 1/5/21018 (email from Sachi Itagaki to Tricia Carter); 3/20/2018 (email from I.
Bergsohn to T. Carter) The final Detailed Project Schedule (A.1.3) was submitted to the Grant Manager on 3/27/2018
as part of the Final Pre-Design Investigation Workplan (B.7.1).
31
A Detailed Project Schedule (Schedule Update 1) was completed on 6/5/2018 and uploaded to FASST for review as
part of Grant Progress Report 1 (6/6/2018). Schedule Update 1 was later updated and submitted (Schedule Update
2_09132018) along with a Time Extension Request to the Grant Manager (9/13/2018). The updated Schedule (Update
2_09132018) was later modified in December 2018 and incorporated into the amended Agreement D1712508-1.
During the second quarter of 2019 the project team developed additional management scenarios for modeling
evaluation. During this process, the District requested that DRI investigate whether a low vertical conductivity layer
representing a clay lens could be extended over a broader area in the model, based on interpretations of subsurface
sections across the South Y area. The added time for model simulation of additional management scenarios and
model recalibration changed the project schedule for the Pre-Design Investigation Report (B.8.2), the Fate and
Transport Modeling Report (B.11.1 and B.11.2), the Feasibility Study Report (B.12.1 and B.12.2), the Interim Remedial
Action Plan (B.13.3.1) and Initial Study Checklists (B.14.1.1 and B.14.1.2). Additional time was also needed for
deliberation of interim remedial alternatives by collaborating water districts. For these reasons and in order to allow
sufficient time for technical review of remaining project submittals, the project team prepared a Request for Time
Extension to change the project completion date from June 30, 2019 to January 31, 2020. The Request for Time
Extension was prepared and submitted to the Grant Manager for review on May 10, 2019. The A-6 Submittal Schedule
attached to the Request was revised and resubmitted to the Grant Manger on May 17, 2019. This schedule was
subsequently incorporated into the Amended Agreement D1712508-2. An updated detailed project schedule
(Schedule Update 3) based on the estimated due dates used in the revised A-6 Submittal was prepared and was
uploaded to FAAST on 08/08/2019.
During the fourth quarter of 2019 an updated Request for Time Extension was prepared and submitted to the Grant
Manager on November 1, 2019. The Request for Time Extension changed the work completion date from January 31,
2020 to June 30, 2020 and was needed to accommodate the cumulative impact of added work to the South Y
Feasibility Study. As part of this request, the Project Director initiated monthly check-in calls with the Grant Manager to
ensure forward progress and completion of the project by the revised completion date. The first of these check-in calls
was conducted on December 6, 2019. These calls will continue through the end of the project. An updated detailed
project schedule (Project Schedule Update 5) was uploaded to FAAST as part of Grant Progress Report 8.
Site Visits (A.1.4) Site walks for planning of the Pre-Design Investigation were performed by the District on 10/17/17;
10/23/17; 1/16/2018 (along with KJC staff); 1/31/2018; 2/8/2018 and 3/30/2018. Site visits with the Grant Manager
were conducted on June 12th and June 26th, 2018.
Photo-Monitoring (A.1.5) Pre-implementation photos of the site areas considered for the Pre-Design Investigation are
provided in Appendix A of the Pre-Design Investigation Work Plan (KJI, 3/23/2018). Photo-monitoring during the PDI
was performed throughout the reporting period. Post-implementation photo monitoring showing site restoration was
completed during November 2018.
Photo monitoring logs documenting pre-, during and post-implementation activities for the Pre-Design Investigation
have been compiled and arranged into a series of sixteen (16) photo logs. These photo logs have been uploaded to
FAAST (5/15/2019).
Item 2 – General Compliance Requirements/Project Effectiveness and Performance - This work item includes
submittal of Global Positioning System (GPS) and Monitoring Plan and Monitoring and Reporting Plan, preparation of
32
the Quality Assurance Project Plan for the Pre-Design Investigation, and preparation and uploading of all groundwater
analytical data collected during the Pre-Design Investigation.
GPS Information (A.2.1) Discrepancies between SWRCB-DFA and GeoTracker GPS survey requirements were
clarified and confirmed with the Grant Manager (7/20/2018). A survey report, prepared by G. Phillips, PLS 7936
(Lumos and Associates, Inc., 9/7/2018) including global positioning system (GPS) information for wells used during the
Feasibility Study was submitted to the Grant Manger on 9/13/2018.
Monitoring and Reporting Plan (A.2.2) Drafts of the Quality Assurance Project Plan (QAPP) and Monitoring and
Reporting Plan (MRP) were submitted to the Grant Manager and Technical Advisory Committee (TAC) for review and
comment on 1/24/2018, as part of the meeting materials for TAC Meeting 1 (1/25/2018). The final deliverable QAPP
(A.2.2.2) and MRP (A.2.2.) were provided to the Grant Manager as part of the draft Final Pre-Design Investigation
Workplan (B.7.2), which also described the requirements for the GPS (A.2.1) and Monitoring Plan (A.2.2). The final
approved documents are included in the South Y Pre-Design Investigation Workplan (Agreement D1712508) Final
prepared by KJC, 3/23/2018.
Groundwater Analytical Data (A.2.3) A Global Identification Number (GIN) for the project site was received from the
Grant Manager (4/12/2018). A new user account for GeoTracker ESI was created (2/19/2019). A Geo Track ESI
(Electronic Submittal of Information) will be created to upload analytical data collected during the PDI.
Item 3 – Permitting -This work item consists of obtaining all public agency approvals, entitlements, or permits required
for activities part of the Pre-Design Investigation.
Site Access Agreements (A.3.1) for performance of the Pre-Design Investigation were negotiated with Liberty Utilities
(Liberty) and the City of South Lake Tahoe (CSLT). The Liberty access agreement was required for
mobilization/demobilization of drilling and water treatment equipment across Liberty property (933 Eloise Avenue). The
Liberty Agreement was executed on 3/5/2018. CSLT required both an Access Agreement and Hold Harmless
Agreement for performance of the Investigation on CSLT property (953 Eloise Avenue). The CSLT Agreements were
executed on 4/26/2018.
Permits (A.3.1) required for performance of the Pre-Design Investigation included an El Dorado County Well
Construction Permit; and a Road Closure/Obstruction in Right of Way Permit from the CSLT. The Well Construction
Permit Application was submitted on 4/18/2018 and approved by the County on 4/19/2018. The Road
Closure/Obstruction in Right of Way Permit was submitted on 4/17/2018 and approved by CSLT on 4/25/2018
The list of Approvals, Entitlements or Permits for the PDI (A.3.1) was uploaded to FAAST on May 31, 2018.
Item 4 – Technical Advisory Committee - This work item consists of establishing a Technical Advisory Committee
(TAC), conducting a kick-off meeting, and holding up to 3 additional TAC conference calls/webcasts. Through the date
of this progress report, five TAC conference call/webcasts have been convened.
The TAC Kick-Off meeting (TAC Meeting 1) was convened via conference call on 1/25/2018. From this meeting a TAC
Roster was established and used to inform the final list of TAC Members (A.4.1).
33
TAC Meeting 2 was convened on June 12, 2018 in the District’s Boardroom, 1275 Meadow Crest Drive, South Lake
Tahoe, CA. This was a joint meeting of the TAC /SAG to; discuss the status of the MOU, review project work items;
discuss initial findings of the Test Hole Drilling program and consider design alternatives proposed for test well
construction; review the Groundwater Fate and Transport Model and consider preliminary definition of remedial
scenarios. Agenda, Meeting Minutes and Sign-In Sheet for this meeting have been uploaded to FASST (11/14/2018).
TAC Meeting 3 was convened as a Video Conference Call on October 23, 2018. This was a joint meeting of the TAC
/SAG to; discuss the status of project work items; remedial action objectives; remedial scenario definition and planned
upcoming project activities. Agenda, Meeting Minutes and Sign-In Sheet for this meeting
have been uploaded to FASST (2/14/2019).
TAC Meeting 4 was convened as a Video Conference Call on February 26, 2019. This was a joint meeting of the TAC
/SAG to; review and discuss development and evaluation of management scenarios using the South Y PCE Model;
initial engineering screening of management scenarios; review the Feasibility Study Report outline; discuss proposed
changes in response to TAC comments following review of the draft PDI Report; and discussion of planned upcoming
project activities. Agenda, Meeting Minutes and Sign-In Sheet for this meeting were uploaded to FASST (5/15/2019).
TAC Meeting 5 was convened as a Video Conference Call on June 21, 2019. This was a joint meeting of the TAC
/SAG to; review and discuss Feasibility Study (FS) screening of final interim remedial alternatives; receive comment on
the draft Fate & Transport Modeling Report; discuss information needs for the FS; notify the TAC/SAG of the revised
project schedule; receive an update of LRWQCB activities in the South Y Area; and notify the TAC/SAG of upcoming
project events and action items. Notes from this meeting are in-preparation and will be uploaded to FASST, along with
the agenda and sign-in sheet, during the next reporting period.
TAC Meeting 6 was convened as a webcast/conference call on October 21, 2019. The meeting was used to discuss
the refined alternative layouts and cost items to be used for detailed analysis to select a preferred remedy during the
Feasibility Study; review recommended actions; and confirm feasibility study requirements with the TAC. Meeting
materials from TAC Meeting 6 are being uploaded to FAAST as part of Grant Progress Report 8.
TAC Meeting 7 was convened as a webcast/conference call on March 6, 2020. The meeting was used to discuss
review comments on the draft Feasibility Study Report and draft Interim Remedial Action Plan (IRAP) received from
the TAC/SAG. Meeting materials from TAC Meeting 7 were uploaded to FAAST as part of Grant Progress Report 9.
TAC Members List (A.4.1) The list was uploaded to FAAST on June 8, 2018. This list was updated to include
Stakeholder Advisory Group (SAG) members, which was provided to the Grant Manager as Handout 1a of the meeting
materials package for TAC Meeting 2 (6/12/2018).
During the second quarter of 2019, the water systems manager for the Tahoe Keys Water Company changed. The
joint TAC/SAG list was updated and was uploaded to FAAST on 08/08/2019.
Kickoff Meeting (4.2) A second Kickoff Meeting (South Y Fate & Transport Modeling Analysis – Engineering Evaluation
Kick-Off)) including the TAC and SAG was convened in the District’s Boardroom on 7/18/2018. The Modeling
Evaluation/FS Kick-Off was used to discuss the F&T Model and approaches for simulating remedial alternatives that
may be further evaluated during the Feasibility Study. Copies of the meeting agenda, sign-in sheets and meeting
minutes will be uploaded to FAAST (11/14/2018).
34
Item 5 – Stakeholder Advisory Group -This work item consists of establishing a Stakeholder Advisory Group (SAG)
and conducting SAG meetings to inform SAG members of Project activities and solicit feedback and comments.
SAG Members List (A.5.1). This list is included on the list of TAC Members on the final TAC Roster (dated 06112018).
This list was provided to the Grant Manager as Handout 1a of the meeting materials for TAC Meeting 2 (6/12/2018).
During the second quarter of 2019, the water systems manager for the Tahoe Keys Water Company changed. The
joint TAC/SAG list was updated and was uploaded to FAAST on 08/08/2019.
SAG Meetings (5.2). The first SAG meeting was held on December 15, 2017 in South Lake Tahoe, CA. The meeting
minutes and sign in sheet were uploaded to FAAST on 5/7/2018. A first joint meeting of the TAC and SAG was
convened on June 12, 2018 in the District’s Boardroom, 1275 Meadow Crest Drive, South Lake Tahoe, CA (see Item 4
above). Agenda, Meeting Minutes and Sign-In Sheet for this meeting were uploaded to FASST in August 2018. A
second joint meeting of the TAC and SAG was convened on July 18, 2018 as part of the South Y F&T Modeling
Analysis- Engineering evaluation Kick-Off (see Item 4.2 above).
A third joint meeting of the TAC/SAG (TAC Meeting 3) was convened as a Video Conference Call on October 23, 2018
(see Item 4 above). An update of South Y Activities was also provided to the Tahoe Valley South Subbasin (6-5.01)
Groundwater Management Plan SAG on 12/21/2018.
A fourth joint meeting of the TAC/SAG (TAC Meeting 4) was convened as a Video Conference Call on February 26,
2019 (see Item 4 above).
A fifth joint meeting of the TAC/SAG (TAC Meeting 5) was convened as a Video Conference Call on June 21, 2019
(see Item 4 above).
A sixth joint meeting of the TAC/SAG (TAC Meeting 6) was convened as a Video Conference Call on October 21, 2019
(see Item 4 above).
A seventh joint meeting of the TAC/SAG (TAC Meeting 7) was convened as a Video Conference Call on March 6,
2020 (see Item 4 above).
Item 6 – Memorandum of Understanding - This work item consists of developing and executing a Memorandum of
Understanding (MOU) with the State Board and Regional Board.
Review comments on a working draft of the MOU (11/22/2017) were submitted to the Grant Manager on 12/15/2017.
An updated draft of the MOU was received from the Grant Manager on 5/23/2018. A redline version of the updated
draft was provided to the Grant Manger on 5/24/2018. The comments were accepted by the Grant Manager on
5/29/2018.
DFA and LRWQCB comments were incorporated into the updated draft MOU. A final draft was distributed to LRWQCB
for review and concurrence (6/20/2018). A copy and original paper copy of the District-signed MOU was submitted to
the Grant Manger on 7/13/2018. DFA formally removed the MOU from the executed Agreement - Amendment 3 dated
March 9, 2020.
35
Item 7 – Pre-Design Investigation Workplan (Cumulative 100% complete)
This work item consists of preparation of a Pre-Design Investigation Workplan which includes a description of the
objectives, tasks, and deliverables; identification of the project area; a description of the test well location and rational;
and investigation activities. The draft Final Workplan (B.7.1) was submitted to the Grant Manager on 3/27/2018. The
Grant Manager, on behalf of the Department of Financial Assistance (DFA), accepted the South Y Pre-Design
Investigation Workplan on 4/4/2018. The accepted final Work Plan was uploaded to the FAAST System on 4/7/2018
(B.7.2).
Item 8 – Pre-Design Investigation and Reporting (Cumulative 100% complete)
This work item consists of conducting the Pre-Design Investigation (PDI) in accordance with the Workplan in Item 7
and preparation, submittal, and circulation of a report that summarizes the activities conducted during the Pre-Design
Investigation.
PDI (8.1) Field work activities for the Pre-Design Investigation (B.8) started on 4/29/2018. Activities completed for the
PDI included Baseline Groundwater Sampling (5/2/2018); Test Hole Coring and Sampling (5/4/2018); and Test Well
Construction and Development (6/29/2018). Step-Drawdown and Constant Rate aquifer tests were performed and
completed during the week of July 8, 2018. All contractor equipment was removed from the site by August 20, 2018.
Investigation-derived Waste was removed from the site for disposal to a non-hazardous waste facility in September
2018.
PDI Changes (8.1.4) Proposed changes to the workplan involved a change in well design to prevent cross-
contamination of water-bearing zones identified in the field and the reduction in duration of the pumping period for the
constant test from 72 to 48 hours. Proposed changes in test well design due to subsurface conditions encountered in
the field was brought to the attention of the Grant Manager by email (6/8/2018) and considered during TAC Meeting 2
(6/12/2018). Proposed changes in the pumping period for the constant test were brought to the attention of the Grant
Manger by email (7/12/2018).
PDI Report (8.2). During Q4 2018, a records search identifying the occurrences of private wells throughout the South Y
Area was completed. Groundwater level elevation readings were collected from more than twenty (20) wells on
October 25, 2019. These data were reviewed and evaluated to determine groundwater flow directions, horizontal and
vertical hydraulic gradients and calculate groundwater velocities during fall (low groundwater) conditions. These data
were incorporated into the Pre-Design Investigation draft technical report. The draft report was completed and
submitted to the TAC for review on 1/10/2019. Comments received from the TAC were reviewed and discussed with
LRWQCB and SWRCB staff on February 8, 2019. Changes to the report in response to TAC comments were
developed and discussed with the TAC on February 26, 2019 during Project Meeting 4.
During Q2 2019, a second round of groundwater level elevation readings were collected on May 23, 2019. These data
were reviewed and evaluated to determine groundwater flow directions, horizontal and vertical hydraulic gradients and
calculate groundwater velocities during spring (high groundwater) conditions. These data were incorporated into the
PDI final technical report. The final report was completed and submitted to the Grant Manger for approval on July 10,
2019 and was uploaded to FASST (11/14/2019).
36
Item 9 – Baseline Human Health Risk Assessment (Cumulative 100% complete)
This work item consists of preparation and submittal of a Baseline Human Health Risk Assessment (BHHRA) Report
that identifies threats to human health as a result of potential exposure to contaminated groundwater in the Project
area using existing data and information from the remedial investigation.
BHHRA (9.1) Tasks for a screening level risk assessment to satisfy the BHHRA requirement (A-3.9.) were defined and
submitted to the Grant Manager for consideration (5/22/2018). The scope of work for the proposed screening level risk
assessment was accepted by the DFA on 5/30/2018. A draft of the BHHRA was completed and was submitted to the
TAC for review on 11/27/2018. Comments received from the TAC were incorporated into the final BHHRA and
submitted to the Grant Manger for approval on 1/2/2019. The final BHHRA report was uploaded to FASST on
1/9/2019.
Item 10 – Feasibility Study Workplan (Cumulative 100% complete)
This work item consists of preparation and submittal of a Feasibility Study Workplan.
FS Workplan (10.1). Work during this period consisted of developing a draft of the Feasibility Study Workplan. The
Workplan includes a description of the objectives and the steps necessary to support the technical and cost analyses
of alternatives, and support the selection of a cost-effective alternative that will provide prevention and/or cleanup of
groundwater contamination in the Project area; a list of remedial action objectives to be addressed; and an appropriate
requirements analysis to ensure the Project is in compliance with regulatory requirements. The draft outline was
submitted to the TAC. The draft of the Workplan was submitted to the District for comments on June 28, 2018 and
submitted to the TAC on September 18, 2018. Comments received from the TAC were incorporated into a final
Feasibility Study Workplan and submitted to the Grant Manager for approval on 11/19/2018. The final FS Workplan
was uploaded to FASST on 12/3/2018.
Item 11 - Groundwater Fate and Transport Modeling (Cumulative 100% complete)
This work item consists of conducting Groundwater Fate and Transport Modeling for the purpose of evaluating
potential implementation projects that will prevent or cleanup groundwater contamination; submittal of a Modeling
Report; and addressing comments received on the Modeling Report.
F&T Modeling (11.1) Work to add a fate and transport (F&T) model to the District’s existing groundwater model was
initiated with the University of Nevada Reno- Desert Research Institute (DRI) on October 20, 2016 (Item B.11).
Conference call/project updates on the development of the F&T Model were provided to stakeholders on 12/7/2016
and 4/5/2017. Work to-date includes planning and development of a local 4 layer model using MODFLOW and MT3D
covering the estimated plume extent, definition of simulated time periods, model inflows/outflows, recharge, boundary
conditions, and hydraulic parameters, An initial matrix of remedial alternatives for modeling analysis was also
developed. The model hydraulic conductivity field was updated in accordance with changes to the regional
groundwater model. Minor PCE model calibration was completed to reflect updated (2017) PCE concentration data. A
draft report describing model development, assumptions and calibration was prepared and submitted to the Project
Director for review. A copy of the draft report was provided to the TAC and Grant Manager in preparation for the model
analysis/engineering evaluation kickoff meeting in July 2018.
DRI used the South Y PCE Model to simulate a variety of management scenarios as defined by the TAC and project
engineering team. A Kick-Off Meeting with DRI and engineering design consultant was convened on July 18, 2018 to
discuss the F&T Model and approaches for simulating remedial alternatives. Copies of the meeting agenda, sign-in
37
sheets and meeting minutes were uploaded to FAAST (11/14/2018). In follow-up to this meeting, a presentation was
developed outlining the results of the simulations discussed with the TAC during a conference call on August 9, 2018.
During the first quarter of 2019, DRI answered questions from Kennedy Jenks Consultants concerning model
simulation assumptions and results, providing additional model detail and running additional best- and worst-case
scenario model simulations (4B, 4C, 5A/5B, 5A2/5B2, 6A/6B and 6A2/6B2) to evaluate new replacement well
simulations and targeted pumping using wells with wellhead treatment for plume control and removal.
District staff requested that DRI perform extra work to evaluate whether an area of very low vertical conductivity
between layers 1 and land 2 can be extended over a broader area than currently represented in the South Y PCE
Model. This very low vertical conductivity layer represents a clay lens identified in subsurface sections across the
South “Y” area that inhibits the vertical migration of PCE. As such this very low vertical conductivity layer has a
significant bearing on the movement and distribution of PCE simulated using the South Y PCE Model. DRI was able to
successfully recalibrate the South Y PCE Model with the following changes from the previous model versions used for
evaluating management scenarios.
• Adjusted screened intervals at LBWC 4 and TKWC 2
• Added expanded clay lens acting as low vertical conductivity zone
• Decreased longitudinal dispersivity to 40m
• Increased vertical dispersivity ratio to 0.015
• Increased transverse dispersivity ratio to 0.6 in layers 1 and 2
• Increased decay half-life to 17 years in layers 1 and 2
• Decreased source term by 30% during years LTLW is in operation
The recalibrated PCE model was used to run simulations under best and worst-case assumptions of the final three
interim remedial alternatives selected for engineering analysis identified as Alternative 1 - Base; Alternative 2 -
Targeted Pumping; and Alternative 3 – Conversion to surface water. The draft Fate & Transport Modeling Report was
completed and submitted to the TAC for review on June 13, 2019. The findings of the final alternatives modeling were
presented during joint TAC/SAG Meeting 5. TAC review comments received on the draft Modeling Report were
reviewed and addressed in the final Modeling Report submitted to the Grant Manger for approval on June 28, 2019.
During the third quarter of 2019, DRI prepared and submitted an addendum to the final Modeling Report. The
addendum presented the modeling evaluation of two additional options based on the Targeted Pumping (Alternative 2)
scenario, as follows: Option1 – using LBWC 5 as lead well; and Option 2 -adding LBWC4R as a new
extraction/replacement well at the LBWC 4 site, under best- and worst-case modeling assumptions. In addition to
providing detailed results of four additional modeling scenarios, the addendum included particle tracking analysis of
several potential sentinel well sites and detailed responses to stakeholder comments received after the final Modeling
Report was submitted to the Grant Manager. The Fate and Transport Modeling Report Addendum was submitted to
the Grant Manager for approval on September 10, 2019. The draft (B.11.1) and final (B.11.2) Fate and Transport
Modeling Reports and Addendum were uploaded to FAAST on 10/02/2019.
Item 12 – Feasibility Study and Reporting (Cumulative 100% complete)
This work item consists of evaluating and developing interim remedial alternatives that prevent or cleanup
contamination of groundwater that serves or has served as a source of drinking water based on the Pre-Design
Investigation Report.
38
During the first quarter of 2019, further coordination/development of remediation alternatives with modeling and PDI
data including several webcast/calls within Kennedy/Jenks, a webcast/call between Kennedy/Jenks and South Tahoe
PUD on 1/25/2019, and a webcast/call DRI on 1/7/2019 and 2/4/2019, review of information provided by DRI, and
under as-needed services, continued refinement of pumping/remediation scenarios for groundwater modeling and
continued evaluation of groundwater modeling results for use in developing remedial alternatives.. A draft outline for
the Feasibility Study was submitted to the District in January 2019. Calls to obtain input on alternatives were
conducted on 3/28/2019 with LBWC and TKWC.
During second quarter of 2019, the final three interim remedial alternatives were developed, considered and refined by
the water purveyors (District, LBWC and TKPOA). Information for identifying infrastructure needs and associated costs
for each alternative were presented during joint TAC/SAG Meeting 5. Available water production data was evaluated
using Title 22 criteria to determine surface water treatment sizing capacity. Infrastructure needs and associated costs
for each alternative were started and are planned to be completed during the next reporting period.
On July 24, 2019, the District received notification from TKPOA, concerning the use of TKWC Wells in Alternative 2,
requiring the removal of the TKWC wells from this alternative. Options for revisions to Alternative 2 were considered
and additional modeling and engineering work to evaluate these options were performed. Email notification of the need
to modify Alternative 2 was provided to the Grant Manger on July 26, 2019.
During the third quarter of 2019, work continued to refine Alternatives 2 and 3 such as addition of extraction well and
treatment using existing air stripper in Alternative 2, and intake and site layout options for Alternative 3, development of
sizing criteria, and evaluating information from the water purveyors to establish the Alternative 1 (Base Treatment)
operations and maintenance costs. Alternative 2 and Alternative 3 conceptual plans were presented to stakeholders
for consideration during a webcast/conference call on 09/09/2019. Based on calls with water agencies on September
9, 2019 and September 17, 2019 and a call with the State Water Resources Control Board on September 19, 2019,
Alternative 2 was updated to include two additional treatment options for PCE removal, Alternative 2 was updated to
use completely new transmission pipelines, and costs were further refined based on this initial feedback. Additional
work included further development of Sections 1-8 of the FS Report.
During the fourth quarter of 2019, work focused on refining layouts and cost items for detailed analysis of alternatives
to select a preferred remedy for the feasibility study. This included further cost analysis to compare costs between
potable re-use and disposal options developed for Alternative 2. This entailed completing a detailed review of Division
of Drinking Water (SWRCB-DDW) requirements under the draft 97-005 process for permitting extremely impaired
water sources (March 25, 2015). Findings from this analysis were incorporated into the feasibility study and discussed
with the TAC during TAC Meeting 6. Other recommended activities for inclusion in the draft Feasibility Study Report
were also developed.
During the first quarter of 2020, the draft FS Report was completed and provided to the Joint TAC/SAG for review and
comment on February 19, 2020. Review comments were compiled in a Comment Log and discussed with the
TAC/SAG during TAC Meeting 7 on March 6, 2020 (see Item 4). The Comment log is included as part of the Meeting
Materials for Item 4.3 to uploaded to FAAST as part of GPR 9. TAC/SAG review comments were addressed in the
draft final FS Report (KJ, March 17, 2020) issued for public comment on March 17, 2020.
The District solicited public comment on the draft final FS Report during a public comment period that ran from March
17 through April 16, 2020. A Notice of Availability was prepared announcing the public comment period and published
39
in the Tahoe Daily Tribune, posted on the District’s web site, and directly emailed to interested parties identified during
public outreach for this project. Public comments received during the comment period were carefully reviewed and
responses prepared for a Responsiveness Summary for both the draft final FS Report and draft IRAP. Where
comments required corrections, these corrections were completed in the final FS Report. The final FS Report was
completed on May 10, 2020 and approved by the Grant Manager on June 12, 2020.
Item 13 – Interim Remedial Action Plan (Cumulative 100% complete)
This work item consists of developing an Interim Remedial Action Plan (IRAP) based on the Feasibility Study that will
lead to the implementation of the preferred remedy and prevent or cleanup contamination of groundwater that serves
or has served as a source of drinking water.
During the reporting period, the draft IRAP was completed and provided to the Joint TAC/SAG for review and comment
on February 27, 2020. Review comments on the draft IRAP were received from SWRCB-DFA; SWRCB-DDW and
from Lukins Brothers Water Company. TAC/SAG review comments were addressed in the draft IRAP presented as
Appendix E in the public draft Feasibility Study Report (KJ, March 17, 2020) issued for public comment on March 17,
2020.
The District solicited public comment on the draft IRAP during a public comment period that ran from March 17 through
April 16, 2020. A Notice of Availability was prepared announcing the public comment period and published in the
Tahoe Daily Tribune, posted on the District’s web site, and directly emailed to interested parties identified during public
outreach for this project. Public comments received during the comment period were carefully reviewed and responses
prepared for a Responsiveness Summary for both the draft FS Report and draft IRAP. Where comments required
corrections, these corrections were completed in the final IRAP. The final IRAP was completed on May 10, 2020 and
approved with the accompanying Responsiveness Summary by the Grant Manager on June 12, 2020.
Item 14 – Environmental Compliance (Cumulative 100% complete)
This work item consists of documentation required under the California Environmental Quality Act (CEQA) for the
proposed implementation project, including preparation of a draft initial study checklist, identification of mitigation
measures and mitigation costs as required under CEQA for the alternatives evaluated in the Feasibility Study Report.
A Notice of Exemption (NOE) for performance of the Pre-Design Investigation was prepared and filed with the County
Clerk, County of El Dorado on March 5, 2018. The NOE was posted by the County Clerk from March 6, 2018 through
April 9, 2018.
During the second quarter of 2019 environmental checklists (CEQA Appendix G; and TRPA Initial Environmental
Checklist) and project descriptions were prepared for Alternative 3 and submitted to the Project Director for initial
review. These checklists and project descriptions will be refined and further developed during the next reporting period.
During the first quarter of 2020, the final environmental checklists (CEQA Appendix G; and TRPA Initial Environmental
Checklist) were completed and submitted to the TAC/SAG for review and comment on February 18, 2020. The final
environmental checklists for the preferred interim remedial alternative (Alternative 2) were presented in Appendix C of
the public draft FS Report (KJ, March 17, 2020) and in the final FS Report (KJ, May 10, 2020).
40
Item 15 – Public Outreach (Cumulative 100% complete)
This work item consists of developing outreach materials including flyers, posters, brochures, and advertisements, and
updates of the Recipient’s website and associated social media web pages to include Project progress and outcomes
and conducting at least one (1) public workshop. Through the date of this progress report, five public workshops have
been convened.
The schedule for public workshops to inform the public on the progress of the Feasibility Study was updated and
incorporated into Schedule Update 2_09132018. A fourth workshop was added to the schedule included in Agreement
D1712508 Amendment 1.
The first public meeting concerning the FS was convened on 2/7/2018 at the CSLT Council Chambers, South Lake
Tahoe, CA (B.15). Notification of this meeting was provided to the TAC during TAC Meeting 2 on 6/12/2018. The
purpose of this meeting were to inform the public and answer questions about current activities being pursued by the
water purveyors in response to this contamination; an update of LRWQCB activities and preliminary findings of the
Pre-Design Investigation A Flyer and press releases announcing the meeting were distributed; a Fact Sheet, FAQ and
concerning the PCE contaminant problem were developed and posted on the District’s website
(http://stpud.us/groundwater). A video recording of the meeting along with a copy of the presentation are also posted
on the website. A copy of the sign-in sheet from this meeting is available from the Project Director.
The second public meeting concerning the FS was convened on 8/8/2018 at the CSLT Council Chambers, South Lake
Tahoe, CA (B.15). Notification of this meeting was provided to the TAC during TAC Meeting 2 on 6/12/2018. The
purpose of this meeting were to inform the public and answer questions about the current (2018) extent of the
contaminant plume; the approaches being pursued by the water purveyors in response to this contamination; and to
present initial (preliminary) findings from the Pre-Design Investigation. A flyer and press release announcing the
meeting were distributed; a Fact Sheet, FAQ and concerning the PCE contaminant problem were developed and
posted on the District’s website (http://stpud.us/groundwater). A video recording of the meeting along with a copy of
the presentation are also posted on the website. A copy of the sign-in sheet from this meeting is available from the
Project Director.
A third public meeting concerning the FS was convened on 11/7/2018 at the CSLT Council Chambers, South Lake
Tahoe, CA (B.15). Notification of this meeting was provided to the TAC during TAC Meeting 3 on 10/23/2018. The
purpose of this meeting were to inform the public and answer questions about the current (2018) extent of the
contaminant plume; the approaches being pursued by the water purveyors in response to this contamination; and the
planned activities for the Feasibility Study. A flyer and press release announcing the meeting were distributed; a Fact
Sheet, FAQ and concerning the PCE contaminant problem were developed and posted on the District’s website
(http://stpud.us/groundwater). A video recording of the meeting along with a copy of the presentation are also posted
on the website. A copy of the sign-in sheet from this meeting is available from the Project Director.
A fourth public meeting concerning the FS was convened on 3/6/2019 at the CSLT Council Chambers, South Lake
Tahoe, CA (B.15). Notification of this meeting was provided to the TAC during TAC Meeting 4 on 2/26/2019. The
purpose of this meeting were to inform the public and answer questions about the South Y PCE Model used to
evaluate different clean-up scenarios to address the South Y Plume. Preliminary findings and results from the
modeling evaluation were presented to the public. A flyer and press release announcing the meeting were distributed;
a Fact Sheet, FAQ and concerning the PCE contaminant problem were developed and posted on the District’s website
41
(http://stpud.us/groundwater). A video recording of the meeting along with a copy of the presentation are also posted
on the website. A copy of the sign-in sheet from this meeting is available from the Project Director.
A fifth public meeting concerning the FS was convened on 6/26/2019 at the CSLT Council Chambers, South Lake
Tahoe, CA (B.15). Notification of this meeting was provided to the TAC during TAC Meeting 5. The purpose of this
meeting were to inform the public and answer questions about the final three interim remedial alternatives selected for
further engineering evaluation for the FS. A press release announcing the meeting was distributed. A video recording
of the meeting along with a copy of the presentation are also posted on the website. A copy of the sign-in sheet from
this meeting is available from the Project Director.
During the first quarter of 2020, an on-line meeting was hosted by the District in-lieu of a sixth public meeting to
present and receive public comment on the draft final FS Report and the preferred alternative presented in the public
draft IRAP. The on-line meeting was required in light of the social distancing guidelines for the COVID-19 public health
emergency declared by El Dorado County on March 12th. The Grant Manger was notified of the proposed change on
March 16, 2020. Email acceptance of the proposed change was received from the Grant Manager on March 17, 2020.
As part of the public outreach for the on-line meeting, the District prepared a Notice of Availability (NOA). The NOA
was used to inform the public of the start of the 30-day comment period for the draft Final FS Report and public draft
IRAP; a description of the IRAP and objectives of the South Y Feasibility Study; schedule and information needed to
participate in the March 31 on-line meeting; and information on how to access the draft final FS Report and public draft
IRAP. The NOA was posted along with the draft final FS Report and public draft IRAP on the District’s web site (March
17, 2020); published in the Public Notices section of the Tahoe Daily Tribune (March 20, 2020); and emailed to the
South Y Interested Parties List including those citizens that provided their email addresses to the District during
previous public meetings on the progress of the South Y Feasibility Study (March 25, 2020). Copies of these notices
were uploaded to FAAST as part of the Public Outreach materials for Item 15.for GPR 9.
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Appendix B - Photographs
Pre-Design Investigation Photo Monitoring: Pre-Implementation
Existing site condition, 933 Eloise Ave pavement, southwest corner of property (within Access Agreement)
April 29, 2018.
Pure Effect Water Treatment Equipment Delivery, April 29, 2018
43
Cascade Drilling Mobilization, TSI 1500 cc Sonic Drill Rig on trailer, April 29, 2018.
Preparing 2,000-lb GAC vessel with ~ 550 gallons of clean water to saturate filter.
44
Safety cones and 500-bbl temporary IDW water storage along north shoulder of Eloise Avenue.
45
Pre-Design Investigation Photo Monitoring: Implementation
Cascade Drilling Health & Safety Sandwich Board
Drilling rig set-up: EW-1 test hole.
46
2” Zone Test Pump - Grundfos 30 SQE130 1 Hp, 200 -240v
7” sonic core sample (31’ – 33’)
47
1 – ½” Standard Penetration Test Sample (23 – 23.5’)
Zone Test I field water quality testing
48
Zone test II pumping water level data collection
Zone Test II water quality sample collection (40 ml VOA sample)
49
Test well construction materials delivery
Test well drilling
50
Test well casing installation – 6”O.D. stainless steel louvered well screen (0.050 slot) and Schedule 80 PVC
blank well casing.
SRI Supreme #6 graded gravel filter pack material
`
51
953 Eloise Avenue EW1 Test Hole and Test Well installations (view looking north).
Test well development (6/29/2018); 6-inch double swab/pumping development tool
EW-1B
EW-1C
Test Hole
52
Test well development line swabbing
Test well line swab - pumping
53
Test well development field water quality testing
Test well development water discharge
54
Dedicated lever loggers and rigging used for aquifer testing.
Grundfos Model 40S50-12, 4-inch 5Hp test pump
55
Aquifer testing 2” discharge line set-up
Test site portable lighting
56
Aquifer test time-series water quality sampling
Aquifer test hand water level readings
57
On-site water treament system- 4 lung bag filtration system pre-filter and two 2,00 lb GAC pressure vessels
filled with virgin coconut shell carbon.
Discharge of treated water to sewer from 500-bbl fluid storage holding tank.
58
Pre-Design Investigation Photo Monitoring: Post - Implementation
Drilling derived waste removal
59
60
Project site restoration
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Appendix C – Supporting Data, Tables, Graphs, or Figures
GENERAL
Joint TAC/SAG Members
AGENCY Member, Title Roles/
Responsibilities
Email Phone # SAG
Member
SWRCB-
DOFA
Tricia Carter, Water
Resource Control
Engineer, Grant
Manager
Responsible for management
and performance of the
Agreement.
Tricia.Carter@Waterboa
rds.ca.gov
(916) 319-
8259
STPUD Ivo Bergsohn, PG,
CHG, Project
Director
Responsible for the overall
management of the
administrative and technical
elements of the Agreement.
ibergsohn@stpud.dst.ca.
us
(530) 543-
6204 X
SWRCB-
DDW
Salvador
Turrubiartes, PE,
Associate Sanitary
Engineer
Responsible for review of
Technical Work Plans and
Technical Reports. Assist in
resolving technical issues
associated with project
implementation in accordance
with the MOU.
Salvador.Turrubiartes@
waterboards.ca.gov
(916) 552-
9998
LRWQCB Brian Grey, PG
Engineering
Geologist
Responsible for review of
Technical Work Plans and
Technical Reports. Assist in
resolving technical issues
associated with project
implementation in accordance
with the MOU.
brian.grey@waterboard
s.ca.gov
(530) 542-
5421
CSLT Jason Burke,
Stormwater
Program
Coordinator
Responsible for review of
Technical Work Plans and
Technical Reports. Assist in
resolving technical issues
associated with project
implementation.
jburke@cityofslt.us
(530) 542-
6038
X
LBWC Jennifer Lukins,
Assistant General
Manager
Responsible for review of
Technical Work Plans and
Technical Reports. Assist in
resolving technical issues
associated with project
implementation.
Jennifer@lukinswater.co
m
(530) 541-
2606
X
62
AGENCY Member, Title Roles/
Responsibilities
Email Phone # SAG
Member
TKPOA Kirk Wooldridge,
General Manager
Responsible for review of
Technical Work Plans and
Technical Reports. Assist in
resolving technical issues
associated with project
implementation.
kwooldridge@tahoekeys
poa.org
(530) 542-
6444 x224
X
SWRCB -
DOFA
Robert Reeves,
Program Manager
for Grant Program
(TAC Alternate)
Assist the Grant Manager and
serve as an Alternate for T.
Carter on the TAC.
Robert.Reeves@waterb
oards.ca.gov
(916) 319-
8254
SWRCB-
DDW
Ali Rezvani,
Sacramento District
Engineer (TAC
Alternate)
Assist the SWRCB-DDW
Sanitary Engineer and serve as
an Alternate for S.
Turrubiartes on the TAC.
Ali.Rezvani@waterboard
s.ca.gov
(916) 445-
5285
TKPOA Andrew Kopania,
Water Quality
Committee (TAC
Alternate)
Assist the TKPOA Water
Company Manager and serve
as an Alternate for D.
Peterson on the TAC.
akopania@sbcglobal.net
63
PRE-DESIGN INVESTIGATION
List of Approvals, Entitlements or Permits
PERMIT AGENCY CONTACT PERMIT FEE
($)
DATE
APPLIED
FINAL
ISSUED
CEQA NOE Office of Planning &
Research; El Dorado
County
County Recorder $ 50.00 3/5/2018 3/5/2018
Well Construction
Permit
El Dorado County
(EDC)
Karen Bender
(573-3453)
$ 327.86 4/18/2018 4/19/2018
Road
Closure/Obstruction
in Right of Way
City of South Lake
Tahoe (CSLT)
Randy Carlson
(542-6033)
$240.00 4/17/2018 4/25/2018
Hold Harmless
Agreement
City of South Lake
Tahoe (CSLT)
Ray Jarvis, Public
Works Director
(530) 542-6031
3/8/2018 4/26/2018
Access Agreement City of South Lake
Tahoe (CSLT)
Ray Jarvis, Public
Works Director
(530) 542-6031
3/8/2018 4/26/2018
Access Agreement Liberty Utilities John Cressaty,
Easement
Coordinator
(530) 543-5260
3/1/2018 3/5/2018
X:\Projects\General\17W006_So Y FS\08_PDI\Field Investigation\EW1 Borehole Log\17W006_Log Forms Page 1 of 4
BOREHOLE LOG Project: South Y Feasibility Study Name: EW-1 (Test Hole)
Project #: 2030-4405/17W006 Owner: South Tahoe Public Utility District DTW:
Location: 953 Eloise Ave Driller: Cascade Drilling Start:
SLT, CA 96150 Rig: TSi 150CC Sonic Rig Finish:
APN:023-301-09-100 Bits: 7" shoe; Flapper; Auger TD: 150
Prepared By: I. Bergsohn, PG, CHg Datum: Ground Surface BH Diam: Nominal 8"Sample IntervalSoil Moisture/ Color (GSA, 1984)/ Geotech SamplesResistance (blows/ft)AlterationUSCS% Clay % Silt % fine sand % Mg-Cg Sand % Gravel 5
wet/10YR 6/6 5 15 25 55
wet/ 5YR 3/4 <5 20 55 15 5
10 wet/10YR 5/4 <5 10 25 55 10
wet/5YR 6/4 <5 10 30 60
15 wet/5YR 6/4 <5 15 30 50
wet/5YR 5/2 5 15 30 25 25
wet/5YR 5/2 19 5<10 25 60
20 46wet/5YR 6/4 5<20 65 1098
wet/ 5YR 6/4 oxy 70 3025x29
x 86
30
wet/ 5YR 6/4 oxy 5 15 70 10
x wet/ 10YR 6/235xxwet/ 10YR 6/2 5 20 55 10x
x moist/ 10YR 6/2 17 oxy 15 60 25
40 x moist/ 10YR 6/6 15 oxy 5 15 75 5
4/30/2018; 11:30
5/4/2018; 18:33
10 - 16': Well graded sand with silt (SW-SM); moderate yellow
brown to light brown, medium and coarse sand, with some fine
sand , subrounded pebbles (1-2" diam), trace silt.
16 - 18': Silty gravel (GM); pale brown, well-graded sand with
considerable decomposed granitic gravel and some cobbles,
trace clayey silt matrix.
18 - 20.5': Silty sand (SM); pale brown fine and medium sand,
some coarse sand, muddy matrix, dense.
20.5 -23': Poorly graded sand (SP); light brown,medium and
coarse sand with some fine sand and few pebbles, very dense.
23 - 26': Silt (ML); light brown with reddish brown streaks, some
fine sand and mica flakes, very dense (K = 1.14 E-04 cm/s).
26 - 31': No Recovery
31 - 38': Poorly graded sand with silt (SP-SM); light brown with
some reddish brown mottling; predominantly medium sand with
some fine and coarse sand, slightly silty, few deeply weathered
granitic pebbles.; ~35' grades to Well-graded sand with silt (SW-
SM) pale yellow brown, mostly medimum sand with some
coarse sand, few deeply weathered granitic gravels, trace silt (K
= 1.38 E-03 cm/s; 4.12E-04 cm/s).
38 - 40': Clayey sand (SC), pale yellow brown clayey sand, mostly
fine sand and few coarse sand coated within a muddy matrix,
massive, compacted (K = 3.50E-08 cm/s; 8.33E-05 cm/s).DepthSoil Material Description: Describe 7"continuous soil core [including observations from
drilling methods and Standard Penetration Tests(SPTs),using an 18" x 1.5"
split-barrel sampler]
0-6': hand auger for utility clearance.
6 -10': Silty sand (SM); dark yellowish orange, well-graded fine -
medium sand with minor coarse sand, considerable silt, slight
muddy matrix, few small gravel (subangular 1-3" dia.)SM
SW-SM
GM
SM
SC
SP
ML
SP-SM
SW-SM
X:\Projects\General\17W006_So Y FS\08_PDI\Field Investigation\EW1 Borehole Log\17W006_Log Forms Page 2 of 4
BOREHOLE LOG Project: South Y Feasibility Study Name: EW-1 (Test Hole)
Project #: 2030-4405/17W006 Owner: South Tahoe Public Utility District DTW:
Location: 953 Eloise Ave Driller: Cascade Drilling Start:
SLT, CA 96150 Rig: TSi 150CC Sonic Rig Finish:
APN:023-301-09-100 Bits: 7" shoe; Flapper; Auger TD: 150
Prepared By: I. Bergsohn, PG, CHg Datum: Ground Surface BH Diam: Nominal 8"Sample IntervalSoil Moisture/ Color (GSA, 1984)/ Geotech SamplesResistance (blows/ft)AlterationUSCS% Clay % Silt % fine sand % Mg-Cg Sand % Gravel 4/30/2018; 11:30
5/4/2018; 18:33
DepthSoil Material Description: Describe 7"continuous soil core [including observations from
drilling methods and Standard Penetration Tests(SPTs),using an 18" x 1.5"
split-barrel sampler]
moist/ 5YR 4/4 35 5 85 10
38 5 10 75 10
45 x moist/ 5YR 3/4 5 50 40 <5
x oxy
x moist/ 5YR 5/2 10 50 35 <5xsl.moist/ 5YR 5/2 <10 70 20 <5
50 oxymoist/ 5YR 4/4 90 10
moist/ 10YR 5/4 ML 100 52 - 52.5': Silt (ML), moderate yellow brown, laminated, dense.
90 105598moist/ 10YR 5/4 49 30 70
moist/ 5YR 5/6 62 5 50 40 560moist/ 5YR 5/6 <5 60 30
moist/ 5YR 5/6 <5 60 30
65 x moist/ 5YR 5/6 5 60 30 <5xmoist/ 5YR 5/6 oxy <5 60 30
moist/ 5YR 5/6 <5 60 30
70 SP-SM 15 60 25moist/ 5YR 5/6 10 90
moist/ 5YR 5/6
75 moist/ 5YR 5/6 50 50
moist/ 5YR 5/6 40 60
80 moist/ 5YR 5/6 50 50wet/ 5YR 5/6 <5 15 70
85 moist/10YR 5/4 oxy 10 40 50moist/10YR 4/2
moist/ 10YR 4/2 oxy 5 20 60 15moist/ 5YR 5/2 oxy 5 45 50905102550 10
70 - 75'; Well graded Sand (SW), light brown medium and coarse
sand, trace fine sand; some fine pebbles at 73'
75- 80': Poorly graded Sand (SP), light brown fine and medium
sand.
84 - 90': Well-graded sand (SW), moderate yellow brown
medium and fine sand, with some thin interbeds of fine pebble
sand, trace silt; hard fe-oxide cement and poorly-graded
medium and coarse sand (SP), dark yellow brown ,with thin silty
fine sand interbeds
40 - 44': Poorly graded sand (SP), moderate brown fine sand
with some Clayey sand (SC); minimal recovery.
44 - 50': Poorly graded fine sand with silt (SP-SM); moderate
brown and pale brown, fine sand with considerable medium
sand and trace gravel, coarse sand and silt, massive; At 46-48'
grades to Well-graded sand with silt (SW -SM) (K = 1.82E-06
cm/s; 1.06E-05 cm/s).
50-52': Poorly graded Sand (SP), moderate brown, fine sand
with some medium sand.
SP-SC
SP
SP
SW
SP-SM
SW-SM
SM
SP
SW
SP
SM
52.5 - 56': Poorly graded Sand (SP), moderate brown, fine sand
with some medium sand.
56 - 58': Silty sand (SM), moderate brown (1' recovery); dense.
80 - 84': Silty sand (SM), pale brown; less than 0.5' recovery
58 - 70'; Poorly graded sand (SP), light brown, fine sand with
some medium sand, trace silt, trace fine pebbles, massive (K=
5.78E-05 cm/s); at 69- 70': grades to fine sand with silt (SP-SM)
X:\Projects\General\17W006_So Y FS\08_PDI\Field Investigation\EW1 Borehole Log\17W006_Log Forms Page 3 of 4
BOREHOLE LOG Project: South Y Feasibility Study Name: EW-1 (Test Hole)
Project #: 2030-4405/17W006 Owner: South Tahoe Public Utility District DTW:
Location: 953 Eloise Ave Driller: Cascade Drilling Start:
SLT, CA 96150 Rig: TSi 150CC Sonic Rig Finish:
APN:023-301-09-100 Bits: 7" shoe; Flapper; Auger TD: 150
Prepared By: I. Bergsohn, PG, CHg Datum: Ground Surface BH Diam: Nominal 8"Sample IntervalSoil Moisture/ Color (GSA, 1984)/ Geotech SamplesResistance (blows/ft)AlterationUSCS% Clay % Silt % fine sand % Mg-Cg Sand % Gravel 4/30/2018; 11:30
5/4/2018; 18:33
DepthSoil Material Description: Describe 7"continuous soil core [including observations from
drilling methods and Standard Penetration Tests(SPTs),using an 18" x 1.5"
split-barrel sampler]
x moist/ 10YR 6/2 75 5 95
X 40x50moist/ 10YR 6/2 <5 95 <595sl moist/ 5YR 5/2 90 10
xx
100 x moist/ N4 88 25 70 5
105 moist/ N4 40 60
moist/ 5YR 4/1 <5 10 70 20
110 moist/ 5YR 5/2 15 50 30 5
moist/ 5YR 5/2 5 80 25
115 moist/ 5YR 5/2 5 65 20 10
moist/ 5YR 5/2 5 40 30 10moist/ 5Y 3/2 25 60 15120
X moist/ 5y 3/2 <5 20 65 <10
X125
moist/ 5Y 3/2 5 70 25560305
moist/ 5Y 5/2 10 90130moist/ 5B 7/1 15 50 25 10
moist/ 5Y 5/2 40 60
135 moist/ 5Y 5/2 5 70 25
moist/ 5Y 5/2 5 60 40
moist/ 5Y 5/2 60 35 5
140 moist/ 10 R 6/2 SC 10 60 30
139 - 140': Clayey sand, pale red fine sand, some medium sand,
coated sub angular and sub-rounded grains in muddy matrix,
dense.
100 - 108': Well-graded sand (SW), gray, fine to coarse sand,
some sub-angular to sub rounded fine pebbles (1-2 cm), trace
silt, very dense.
108 - 110': Silty sand (SM), brownish gray fine sand, trace silt
and clay.
110 - 120':Well-graded sand (SW), light olive gray, fine sand,
with some medium and coarse sand, trace silt, fine sub-rounded
pebbles (up to 4 cm) common, few cobbles (6 cm) and muddy
matrix. At 117.5' sharp contact with Well-graded sand (SW) olive
gray predominantly medium and coarse sand with some fine
sand and fine pebbles (117.5 - 119')
122- 128': Well graded gravelly sand (SW), olive gray med and
coarse pebbly sand, trace silt, mostly fine sub-rounded pebbles,
few cobbles (8 cm) near base of sands at 127'; at 128' some
weathered carbonized wood (?) fragments (5 cm) (K= 7.42E-05
cm/s).
90-94': Poorly graded sand (SP), pale brown fine sand, trace silt,
micaceous, fe-oxide streaks aligned along thin inclined bedding
planes, dense to very dense.
moist/ 5Y 3/2
SP
CL
SW
SM
130 - 132': Well graded sand with silt (SW-SM), light olive gray
fine sand, some medium and coarse sand, few large pebbles,
weathered ash clay matrix.
128- 130' : Clayey sand (SC), light olive gray and bluish gray fine
sand, weathered ash clay matrix coating grains.
SW
SW
SC
94 - 100': Clay (CL), pale brown, trace silt, laminated, distinct
varves from 96- 98' , plastic (K = 2.86E-07 cm/s)
120 - 122'; No Recovery
132 - 139': Well-graded Sand (SW), light olive gray fine sand,
some medium sand, trace silt; sharp bottom contact at 139'
SW-SM
SW
X:\Projects\General\17W006_So Y FS\08_PDI\Field Investigation\EW1 Borehole Log\17W006_Log Forms Page 4 of 4
BOREHOLE LOG Project: South Y Feasibility Study Name: EW-1 (Test Hole)
Project #: 2030-4405/17W006 Owner: South Tahoe Public Utility District DTW:
Location: 953 Eloise Ave Driller: Cascade Drilling Start:
SLT, CA 96150 Rig: TSi 150CC Sonic Rig Finish:
APN:023-301-09-100 Bits: 7" shoe; Flapper; Auger TD: 150
Prepared By: I. Bergsohn, PG, CHg Datum: Ground Surface BH Diam: Nominal 8"Sample IntervalSoil Moisture/ Color (GSA, 1984)/ Geotech SamplesResistance (blows/ft)AlterationUSCS% Clay % Silt % fine sand % Mg-Cg Sand % Gravel 4/30/2018; 11:30
5/4/2018; 18:33
DepthSoil Material Description: Describe 7"continuous soil core [including observations from
drilling methods and Standard Penetration Tests(SPTs),using an 18" x 1.5"
split-barrel sampler]
moist/ 5YR 6/1 SP 100 140 - 141': Poorly-graded sand (SP) light brown fine sandmoist/ 5YR 4/1 5 25 70moist/ 5YR 6/1 5 20 65 10
145 moist/ 5YR 6/1 25 75
moist/ 5YR 6/1 5 85 10
150 x sl moist/ 5YR 6/1 ML <5 95 149 - 150' Silt (ML), lt. brownish grey, trace clay, very dense (K=
3.64E-06 cm/s).
141 - 146': Well-graded sand with silt (SW-SM) light brownish
gray and brownish gray medium and coarse sand with fine sand,
some fine pebbles, trace silt.SW - SM
146 - 149': Poorly graded sand (SP) light brownish gray fine
sand, some coarse sand, trace silt.SP
POORLY GRADED SAND (SP) YELLOWISH BROWNOVERALL, TR. SCATTERED SUBROUNDED COARSE
GRAINED SAND, ~50% MEDIUM GRAINED SAND,~50% FINE GRAINED SAND, LOOSE, WET
POORLY GRADED SAND (SP) VERY DARK GRAYISHBROWN OVERALL, TR. COARSE GRAINED SAND,
~80-90% FINE GRAINED SAND, ~10% SILT, WET
WELL GRADED SAND (SW) DARK YELLOWISHBROWN OVERALL, TR. FINE GRAVEL, ~10-15%
COARSE GRAINED SAND, ~50% MEDIUM GRAINEDSAND, ~40% FINE GRAINED SAND
WELL GRADED SAND WITH SILT (SW) DARKYELLOWISH BROWN OVERALL, TR. FINE GRAVEL,TR. COARSE GRAINED SAND, ~40% MEDIUM
GRAINED SAND, ~40% FINE GRAINED SAND, ~10-15%SILT, VERY DENSE
WELL GRADED SAND WITH GRAVEL (SW) GRAYISHBROWN OVERALL, TR. COBBLES, ~10%SUBROUNDED GRAVEL TO 1-INCH, ~10% COARSE
GRAINED SAND, ~60% FINE GRAINED SAND, ~10%SILT, VERY DENSE AND COHESIVE
19 FT. COLOR INCLUDES PALE BROWN
POORLY GRADED SAND (SP) PALE BROWN TOLIGHT YELLOWISH BROWN, ~100% FINE GRAINED
SAND, VERY DENSE
20.5 - 21 FT. SOME COARSE GRAINED SAND AND
MEDIUM GRAINED SAND
SANDY SILT (ML) LIGHT BROWNISH GRAY AND
YELLOWISH BROWN, ~25-50% FINE GRAINED SANDINCLUDING MICA, ~50% SILT, VERY STIFF, NOPLASTICITY
25 FT. UP TO ~50% FINE GRAINED SAND
WELL GRADED SAND (SW) YELLOWISH BROWN
OVERALL, BASED UPON GRADATION TESTS AT 33-35FT. AND 35-37 FT.: 1.4 - 9.6% FINE GRAVEL, 10.5 -17.1% COARSE GRAINED SAND, 62.0 - 43.3% MEDIUM
GRAINED SAND, 20.5-22.9% FINE GRAINED SAND,5.6-7.1% SILT, DENSE, WET, APPEARANCE OF
HIGHLY WEATHERED GRANITIC CLASTS TO COBBLESIZE, POSS. WEATHERED IN PLACE
EW-124-24.5
EW-125/25.5
EW-133-35
10YR5/4
10YR3/2
10YR4/6
10YR5/2
10YR6/3
10YR6/3
10YR6/4
10YR 6/2
10YR 5/8
10YR5/4
221721192713485391217133650
PID = 0.9 PPM
Bentonite-CementGrout
PID = 0.5 PPM
PID = 0 PPM
24.5-25.5 ft.K=1.14E-04
33-35 ft.
K=1.38E-03
Zone Test 1PCE: 30.7 ug/lToluene 0.9 ug/l
SP
SP
SW
SW
SW
SP
ML
SW
HAND AUGER
3
8
0.8
1.5
1.5
0.5
0.5
6
BORING LOCATION
DRILLING COMPANY
DRILLING METHOD(S)
ISOLATION CASING
BLANK CASING
SLOTTED CASING
SIZE AND TYPE OF FILTER PACK
SEAL
GROUT
WELL COMPLETION
T. Hatch
7" core with 8" Casing
n/a
ELEVATION AND DATUM
DATE STARTED
Cascade Drilling
Sonic - TS 150
8-in. Sonic Drive Casing (Temp.)
4-in. SCH 40 PVC (Temp.)
4-in. SS CWW 0.050 in. slot (Temp.)
n/a
n/a
3-5% Bentonite Cement
Boring Name EW-1 Pilot Boring
n/a
M. McLeod
Sonic core; Standard
Pen. Test
n/a
n/a
n/a
n/a
n/a
0
LOGGED BY
n/a
n/a
n/a
n/a
n/a
130
STATIC WATER ELEVATION
150.0 ft. bgs
SAMPLING METHODS
Project Number 1770027.00
953 Eloise St., South Lake Tahoe
FT.
FT.
FT.
FT.
FT.
FT.
TO
TO
TO
TO
TO
TO
FROM
FROM
FROM
FROM
FROM
FROM
DRILLER
DRILL BIT(S) SIZE
STAND PIPE FT.
Project Name South Tahoe PUD
TOTAL DEPTH
DATE COMPLETED
SURFACE HOUSING
4/30/18 5/5/18
Boring & Well Construction Log
F-40.1
(6-87) (3-88) (8-90)
Penetr.Resist.Blows/6"
DrillDepth(Feet)
USCSLog Lithology Color SAMPLE DESCRIPTION and DRILLING REMARKSRecovery
(Feet)
1 4OFSHEET
Type& No.
SAMPLES BACKFILL DETAILS
Kennedy/Jenks Consultants
BORING & WELL CONSTRUCTION 1770027.00.GPJ KENNEDY JENKS.GDT 11/16/185
10
15
20
25
30
35
WELL GRADED SAND CONT'D
SANDY SILT (ML) YELLOWISH BROWN OVERALL,MIXED LAYERS OF SAND WITH SILT, AND SMALLAMOUNT OF CLAY; SAND IS MAINLY FINE WITH
STREAKS OF 10YR 5/8 OXIDATION, SOFT, NOPLASTICITY
GRADES TO ALTERNATING LAYERS OF SILTYSAND AND POORLY GRADED SAND (SM) SAND ISMAINLY ~90% FINE GRAINED SAND, WITH ~10% SILT,
LOOSE, WET
(AQUIFER ZONE TKZ5) POORLY GRADED SAND(SP) LIGHT YELLOWISH BROWN OVERALL, ~70-80%
MEDIUM GRAINED SAND, ~20-30% FINE GRAINEDSAND, DENSE, WET
(AQUIFER ZONE TKZ5) WELL GRADED SAND (SW)YELLOWISH BROWN OVERALL, ~10% SUBROUNDEDCOARSE GRAINED SAND, ~30% MEDIUM GRAINED
SAND, ~60% MEDIUM GRAINED SAND, DENSE, WET
(AQUIFER ZONE TKZ5) POORLY GRADED SAND
(SP) YELLOWISH BROWN OVERALL, BASED UPONGRADATION TESTS AT 44-46 FT. AND 46-48 FT.:0.2-0.1% FINE GRAVEL, 3.7-3.6% COARSE GRAINED
SAND, 37% MEDIUM GRAINED SAND, 50.9-24.0% FINEGRAINED SAND, 8.1-10.3% SILT, VERY DENSE, WET
50 FT. COLOR CHANGES SLIGHTLY, MATERIALBECOMES DENSER
54 FT. THIN SUBHORIZONTAL LAYER OFFINE-GRAINED SILTY SAND
55.5 FT. SOME MEDIUM GRAINED FELDSPAR GRAINS
(AQUIFER ZONE TKZ5) WELL GRADED SAND (SW)LIGHT YELLOWISH BROWN OVERALL, TR.
SUBROUNDED COARSE GRAINED SAND, ~10-20%MEDIUM GRAINED SAND QUARTZ AND FELDSPAR,
~70-80% FINE GRAINED SAND INCLUDING MICA,DENSE, WET
(AQUIFER ZONE TKZ5) POORLY GRADED SAND
(SP) YELLOWISH BROWN OVERALL, BASED UPONGRADATION TESTS AT 64-66 FT.: 1.2% COARSEGRAINED SAND, 30.7% MEDIUM GRAINED SAND,
61.8% FINE GRAINED SAND, 6.3% SILT, MASSIVE,DENSE, WET
EW-135-37
EW-138.5-39EW-139-39.5
EW-144-46
EW-146-48
EW-164-66
10YR5/4
10YR 6/4
10YR5/4
10YR4/4
10YR6/4
10YR5/4
1189496121718171721
2948502018311250
35-37 ft.:K=4.12E-04
38.5-39 ft.K=3.5E-08
39-39.5 ft.K=8.33E-05
PID = 0.5 PPMPID = 0.7 PPM
44-46 ft.K=1.82E-06
PID = 0.6 PPM
46-48 ft.
K=1.06E-05
Zone Test 2
Benzene 112 ug/l
Ethyl Benzene:4.2 ug/lStyrene 0.6 ug/l
PCE 66 ug/lTCE 2.8 ug/l Toluene 18 ug/l
Xylenes (Tot.) 0.9 ug/lPID = 0.6 PPM
PID = 1.2 PPM
Zone Test 3PCE: 1.5 ug/lZone Test 3
PCE: 1.5 ug/l64-66 ft.K=5.78E-05
PID = 2.0 PPM
PID = 0.9 PPM
Bentonite-CementGrout
PID = 0.3 PPM
SW
ML
SM
SP
SW
SP
SW
SP
1.5
0.8
0.5
1
7.1
2
1.5
1.5
0
11.5
9.4
Project Name South Tahoe PUD Project Number 1770027.00 Boring Name EW-1 Pilot Boring
Boring & Well Construction Log
F-40.1
(6-87) (3-88) (8-90)
Penetr.Resist.Blows/6"
DrillDepth(Feet)
USCSLog Lithology Color SAMPLE DESCRIPTION and DRILLING REMARKSRecovery
(Feet)
2 4OFSHEET
Type& No.
SAMPLES BACKFILL DETAILS
Kennedy/Jenks Consultants
BORING & WELL CONSTRUCTION 1770027.00.GPJ KENNEDY JENKS.GDT 11/16/1840
45
50
55
60
65
70
75
80
(AQUIFER ZONE TKZ5) SILTY SAND (SM) PALEBROWN WITH SUBHORIZONTAL YELLOWISH BROWN
BANDING, ~60-80% FINE GRAINED SAND INCLUDINGMICAS, ~20-40% SILT, DENSE, NO PLASTICITY, WET
(AQUIFER ZONE TKZ5) WELL GRADED SAND (SW)
PALE BROWN OVERALL, <10% SUBROUNDEDCOARSE GRAINED SAND, ~30-40% MEDIUM GRAINED
SAND, ~50% FINE GRAINED SAND INCLUDING MICA,MASSIVE, DENSE, WET
(AQUIFER ZONE TKZ5) SANDY SILT (ML) PALE
BROWN WITH SUBHORIZONTAL AND CURVEDYELLOWISH BROWN BANDING, FINE GRAINED SAND
VARIES FROM ~20-50%, SILT VARIES ~80-50%, VERYSTIFF, NO TO LOW PLASTICITY, WET
(AQUIFER ZONE TKZ5) SILTY SAND (SM) BROWN
TO YELLOWISH BROWN WITH BANDS OF STRONGBROWN AND STREAKS OF VERY DARK GRAYISHBROWN, ~90% FINE GRAINED SAND, ~10-20% SILT,
DENSE, WET
SILT TO SANDY SILT (ML) BROWN OVERALL WITH
THIN SUBHORIZONTAL STREAKS OF YELLOWISHBROWN, UP TO ~50% FINE GRAINED SANDINCLUDING MICA, WITH SAND DECREASING FROM
94 TO 96 FT., SOME THIN SUBHORIZONTAL SANDYLAYERS PRESENT
(REGIONAL TKZ5/TKZ4 AQUITARD) CLAY TO SILTYCLAY (CL) DARK GRAYISH BROWN OVERALL, VERYSTIFF, LOW PLASTICITY, HIGH TOUGHNESS, LOW
TO SLOW DILANTANCY
POORLY GRADED SAND (SP) 10YR 5/8 YELLOWISHBROWN TO 2.5Y N4/0 DARK GRAY
WELL GRADED SAND (SW) DARK GRAY, GRAY,GRADING TO LIGHT YELLOWISH BROWN, ~5% FINE
GRAVEL, INCLUDING SUBROUNDED CLASTS ANDGRANITIC CLASTS WEATHERING IN PLACE, ~5%COARSE GRAINED SAND, ~30-40% MEDIUM GRAINED
SAND, ~30% FINE GRAINED SAND
(AQUIFER ZONE TKZ4) WELL GRADED SAND WITHGRAVEL (SW) DARK GRAYISH BROWN OVERALL,
~10% GRAVEL TO 1-INCH, UP TO ~20% COARSEGRAINED SAND, ~20-30% MEDIUM GRAINED SAND,~30% FINE GRAINED SAND, VERY DENSE, WET
(AQUIFER ZONE TKZ4) WELL GRADED SAND (SW)DARK GRAY OVERALL, BASED UPON GRADATION
TESTS AT 122-127 FT.: 3.6% FINE GRAVEL, 25.1%COARSE GRAINED SAND, 37.0% MEDIUM GRAINEDSAND, 24.0% FINE GRAINED SAND, 7.6% SILT,DENSE, MASSIVE, WET
EW-196-98
EW-1122-124
10YR 6/3
10YR 5/8
10YR 6/310YR 5/47.5YR 4/6
10YR 4/310YR 5/8
10YR4/2
**
2.5YN4/0
10YR8/1
10YR6/4
10YR4/2
2.5YN4/0
293639
253550/0.4Corefrom90-100 ft.
3850
PID = 1.1 PPM
PID = 1.0 PPM
96-98 ft.
K=2.86E-07
Bentonite-CementGrout
PID = 0.3 PPM
PID = 0.3 PPM
Zone Test 5PCE: <0.5 ug/lTCE: 0.6 ug/l
122-124 ft. K=7.42E-05
SM
SW
ML
SM
ML
CL
SP
SW
SW
SW
1
1.5
0.4
8
0.4
4.2
9
Project Name South Tahoe PUD Project Number 1770027.00 Boring Name EW-1 Pilot Boring
Boring & Well Construction Log
F-40.1
(6-87) (3-88) (8-90)
Penetr.Resist.Blows/6"
DrillDepth(Feet)
USCSLog Lithology Color SAMPLE DESCRIPTION and DRILLING REMARKSRecovery
(Feet)
3 4OFSHEET
Type& No.
SAMPLES BACKFILL DETAILS
Kennedy/Jenks Consultants
BORING & WELL CONSTRUCTION 1770027.00.GPJ KENNEDY JENKS.GDT 11/16/1885
90
95
100
105
110
115
120
125
WELL GRADED SAND CONT'D
COMPLEX ZONE OF MIXED AND DEFORMED
LAYERS OF SILT AND WELL GRADED SAND (ML)SILTY LAYERS COLOR INCUDES YELLOWISHBROWN (10YR 5/8), GRAY (2.5Y N5), OLIVE GRAY
(2.5Y N4-5Y 5/1); WELL GRADED SAND LAYERSTYPICALLY 2.5Y N8, SILTY LAYERS ARE TYPICALLYUP TO ~50% FINE GRAINED SAND, ~50% SILT, VERY
STIFF, NO PLASTICITY, WET, ALTERNATING LAYERSARE ~1-2 INCHES THICK AND CURVED ANDDEFORMED; DARK GRAY CLASTS ARE POSSIBLE
ORGANIC MATTER
(AQUIFER ZONE TKZ4) SILTY SAND TO POORLY
GRADED SAND (SM-SP) PINK FROM 130 - 131 FT,DARK GRAY BELOW, ~50% MEDIUM GRAINED SAND,~50% FINE GRAINED SAND TO 134 FT., GRADING TO
~80% FINE GRAINED SAND ~10-20% SILT
(AQUIFER ZONE TKZ4) SILTY SAND (SM) PINK AND
GRAY, ~60-80% FINE GRAINED SAND INCLUDINGMICAS, ~20-40% SILT, VERY DENSE AND COHESIVE,
NO PLASTICITY
(AQUIFER ZONE TKZ4) POORLY GRADED SAND(SP) GRAY OVERALL, TR. COARSE GRAINED SAND,
~100% FINE GRAINED SAND, ~10%? SILT, FAINTSUBHORIZONTAL LAYERING
(AQUIFER ZONE TKZ4) SILTY SAND TO SANDY SILT
(SM-ML) PINK AND GRAY, ~40-60% FINE GRAINEDSAND, ~40-60% SILT, VERY STIFF, NO PLASTICITYNOTES
1. ALL CONTACTS APPROXIMATE
2. BGS: BELOW GROUND SURFACE
3. COLOR DESIGNATION IN ACCORDANCE WITH THE MUNSELL SOIL COLOR CHARTS(KOLLMORGEN INSTRUMENTS CORPORATION, 1990)
4. PID = PHOTOIONIZATION DETECTOR HEADSPACE READING
5. PPM = PARTS PER MILLION
6. SOIL CLASSIFIED IN ACCORDANCE WITH THE UNIFIED SOIL CLASSIFICATION SYSTEM, ASTM
D-2488-93
7. ZONE TEST 1: SCREEN 31-36 FT. BGS; CASING TO 27 FT. BGS
8. ZONE TEST 2: SCREEN 41 FT. - 51 FT. BGS; CASING TO 38 FT. BGS
9. ZONE TEST 3: SCREEN 59.5 FT. - 69.5 FT. BGS; CASING TO 58 FT. BGS
10. ZONE TEST 5: SCREEN 120 FT. - 125 FT. BGS; CASING TO 117 FT. BGS
11. ZONE TEST COMPONENTS INCLUDE 4-INCH SCH40 PVC BLANK CASING AND 4-INCHSTAINLESS STEEL CONTINUOUS WIRE WOUND WELL SCREEN WITH 0.050-INCH OPENINGS.FILTER SAND WAS CEMEX #4/12 SAND.
12. K = PERMEABILITY IN CENTIMETERS/SECOND
EW-1150
2.5YN4/0
**
5Y5/1
5YR 7/3
10YR6/1
5YR 7/310YR 6/1
Bentonite-Cement
Grout
Slough
150 ft.
K=3.64E-06
SW
ML
SM-SP
SM
SP
SM-ML
8
18.4
Project Name South Tahoe PUD Project Number 1770027.00 Boring Name EW-1 Pilot Boring
Boring & Well Construction Log
F-40.1
(6-87) (3-88) (8-90)
Penetr.Resist.Blows/6"
DrillDepth(Feet)
USCSLog Lithology Color SAMPLE DESCRIPTION and DRILLING REMARKSRecovery
(Feet)
4 4OFSHEET
Type& No.
SAMPLES BACKFILL DETAILS
Kennedy/Jenks Consultants
BORING & WELL CONSTRUCTION 1770027.00.GPJ KENNEDY JENKS.GDT 11/16/18130
135
140
145
150
POORLY GRADED SAND (SP) YELLOWISH BROWNOVERALL, TR. SCATTERED SUBROUNDED COARSE
GRAINED SAND, ~50% MEDIUM GRAINED SAND,~50% FINE GRAINED SAND, LOOSE, WET
POORLY GRADED SAND (SP) VERY DARK GRAYISH
BROWN OVERALL, TR. COARSE GRAINED SAND,~80-90% FINE GRAINED SAND, ~10% SILT, WET
WELL GRADED SAND (SW) DARK YELLOWISHBROWN OVERALL, TR. FINE GRAVEL, ~10-15%COARSE GRAINED SAND, ~50% MEDIUM GRAINED
SAND, ~40% FINE GRAINED SAND
WELL GRADED SAND WITH SILT (SW) DARKYELLOWISH BROWN OVERALL, TR. FINE GRAVEL,
TR. COARSE GRAINED SAND, ~40% MEDIUMGRAINED SAND, ~40% FINE GRAINED SAND, ~10-15%
SILT, VERY DENSE
WELL GRADED SAND WITH GRAVEL (SW) GRAYISHBROWN OVERALL, TR. COBBLES, ~10%
SUBROUNDED GRAVEL TO 1-INCH, ~10% COARSEGRAINED SAND, ~60% FINE GRAINED SAND, ~10%
SILT, VERY DENSE AND COHESIVE
19 FT. COLOR INCLUDES PALE BROWN
POORLY GRADED SAND (SP) PALE BROWN TOLIGHT YELLOWISH BROWN, ~100% FINE GRAINEDSAND, VERY DENSE
20.5 - 21 FT. SOME COARSE GRAINED SAND ANDMEDIUM GRAINED SAND
SANDY SILT (ML) LIGHT BROWNISH GRAY ANDYELLOWISH BROWN, ~25-50% FINE GRAINED SANDINCLUDING MICA, ~50% SILT, VERY STIFF, NOPLASTICITY
25 FT. UP TO ~50% FINE GRAINED SAND
WELL GRADED SAND (SW) YELLOWISH BROWNOVERALL, BASED UPON GRADATION TESTS AT 33-35
FT. AND 35-37 FT.: 1.4 - 9.6% FINE GRAVEL, 10.5 -17.1% COARSE GRAINED SAND, 62.0 - 43.3% MEDIUMGRAINED SAND, 20.5-22.9% FINE GRAINED SAND,
5.6-7.1% SILT, DENSE, WET, APPEARANCE OFHIGHLY WEATHERED GRANITIC CLASTS TO COBBLESIZE, POSS. WEATHERED IN PLACE
NOTES
1. SOIL DESCRIPTION AND SAMPLES FROM EW-1 PILOT HOLE CORE
2. EW-1 PILOT HOLE WAS DRILLED TO 150 FT.
3. EW-1B LOCATED APPX. 10 FEET SOUTHWEST OF EW-1 PILOT HOLE
4. ALL CONTACTS APPROXIMATE
5. BGS: BELOW GROUND SURFACE
6. COLOR DESIGNATION IN ACCORDANCE WITH THE MUNSELL SOIL COLOR CHARTS(KOLLMORGEN INSTRUMENTS CORPORATION, 1990)
7. SOIL CLASSIFIED IN ACCORDANCE WITH THE UNIFIED SOIL CLASSIFICATION SYSTEM, ASTMD-2488-93
8. TOP OF STEEL STANDPIPE SURVEYED ON 20 AUGUST 2018
10YR5/4
10YR3/2
10YR4/6
10YR5/2
10YR6/310YR6/3
10YR6/410YR 6/2
10YR 5/8
10YR5/4
Cement GroutSeal
Centralizer
6-in. SCH80
PVC Threaded
Bentonite Seal
Centralizer
SRI#6 GravelFilter Pack
Stainless SteelStandard FloShutter Screen
0.050-in.opening
Centralizer
SCH 80 PVCSump
SP
SP
SW
SW
SW
SP
ML
SW
BORING LOCATION
DRILLING COMPANY
DRILLING METHOD(S)
ISOLATION CASING
BLANK CASING
SLOTTED CASING
SIZE AND TYPE OF FILTER PACK
SEAL
GROUT
WELL COMPLETION
T. Hatch
10-1/2" Casing with 10-3/4" Cutter
6247.82 ft.
Top of Steel Lid: 6263.42 ft.ELEVATION AND DATUM
DATE STARTED
Cascade Drilling
Sonic - TS 150
Sonic Drive Casing (Temp.)
6-in. SCH80 PVC Threaded
6-in. Stainless Steel 0.050-inch Standard Flo Shutter
SRI #6
Cetco Puregold Medium Bentonite Chips
2% Bentonite-Cement Grout
Well Name EW-1B
2.5
M. McLeod 7129142.910
None
n/a
+1.86
25.6
24.8
21
0
LOGGED BY
n/a
25.6
35.6
38
24.8
21
STATIC WATER ELEVATION
38.0 ft. bgs
SAMPLING METHODS
Project Number 1770027.00
EAST
953 Eloise St., South Lake Tahoe, 10 feet Southwest of Pilot Boring
FT.
FT.
FT.
FT.
FT.
FT.
TO
TO
TO
TO
TO
TO
FROM
FROM
FROM
FROM
FROM
FROM
DRILLER
DRILL BIT(S) SIZE
STAND PIPE FT.
Project Name South Tahoe PUD
NORTH
TOTAL DEPTH
DATE COMPLETED
SURFACE HOUSING
6/27/18 6/28/18
2101924.800
X
Well cap
Stand pipe
Boring & Well Construction Log
F-40.1
(6-87) (3-88) (8-90)
Penetr.Resist.Blows/6"
DrillDepth(Feet)
USCSLog Lithology Color SAMPLE DESCRIPTION and DRILLING REMARKSRecovery
(Feet)
1 1OFSHEET
Type& No.
SAMPLES WELL CONSTRUCTION
Kennedy/Jenks Consultants
BORING & WELL CONSTRUCTION 1770027.00.GPJ KENNEDY JENKS.GDT 9/19/185
10
15
20
25
30
35
POORLY GRADED SAND (SP) YELLOWISH BROWNOVERALL, TR. SCATTERED SUBROUNDED COARSE
GRAINED SAND, ~50% MEDIUM GRAINED SAND,~50% FINE GRAINED SAND, LOOSE, WET
POORLY GRADED SAND (SP) VERY DARK GRAYISHBROWN OVERALL, TR. COARSE GRAINED SAND,
~80-90% FINE GRAINED SAND, ~10% SILT, WET
WELL GRADED SAND (SW) DARK YELLOWISHBROWN OVERALL, TR. FINE GRAVEL, ~10-15%
COARSE GRAINED SAND, ~50% MEDIUM GRAINEDSAND, ~40% FINE GRAINED SAND
WELL GRADED SAND WITH SILT (SW) DARKYELLOWISH BROWN OVERALL, TR. FINE GRAVEL,TR. COARSE GRAINED SAND, ~40% MEDIUM
GRAINED SAND, ~40% FINE GRAINED SAND, ~10-15%SILT, VERY DENSE
WELL GRADED SAND WITH GRAVEL (SW) GRAYISHBROWN OVERALL, TR. COBBLES, ~10%SUBROUNDED GRAVEL TO 1-INCH, ~10% COARSE
GRAINED SAND, ~60% FINE GRAINED SAND, ~10%SILT, VERY DENSE AND COHESIVE
19 FT. COLOR INCLUDES PALE BROWN
POORLY GRADED SAND (SP) PALE BROWN TOLIGHT YELLOWISH BROWN, ~100% FINE GRAINED
SAND, VERY DENSE
20.5 - 21 FT. SOME COARSE GRAINED SAND AND
MEDIUM GRAINED SAND
SANDY SILT (ML) LIGHT BROWNISH GRAY AND
YELLOWISH BROWN, ~25-50% FINE GRAINED SANDINCLUDING MICA, ~50% SILT, VERY STIFF, NOPLASTICITY
25 FT. UP TO ~50% FINE GRAINED SAND
WELL GRADED SAND (SW) YELLOWISH BROWN
OVERALL, BASED UPON GRADATION TESTS AT 33-35FT. AND 35-37 FT.: 1.4 - 9.6% FINE GRAVEL, 10.5 -17.1% COARSE GRAINED SAND, 62.0 - 43.3% MEDIUM
GRAINED SAND, 20.5-22.9% FINE GRAINED SAND,5.6-7.1% SILT, DENSE, WET, APPEARANCE OF
HIGHLY WEATHERED GRANITIC CLASTS TO COBBLESIZE, POSS. WEATHERED IN PLACE
10YR5/4
10YR3/2
10YR4/6
10YR5/2
10YR6/3
10YR6/3
10YR6/4
10YR 6/2
10YR 5/8
10YR5/4
Centralizer
Grout Seal
6-in. SCH80PVC Threaded
Blank Casing
SP
SP
SW
SW
SW
SP
ML
SW
BORING LOCATION
DRILLING COMPANY
DRILLING METHOD(S)
ISOLATION CASING
BLANK CASING
SLOTTED CASING
SIZE AND TYPE OF FILTER PACK
SEAL
GROUT
WELL COMPLETION
T. Hatch
10-1/2" Casing with 10-3/4" Cutter
6241.92 ft.
Top of Steel Lid: 6263.40 ft.ELEVATION AND DATUM
DATE STARTED
Cascade Drilling
Sonic - TS 150
Sonic Drive Casing (Temp.)
6-in. SCH80 PVC Threaded
6-in. Stainless Steel 0.050-inch Standard Flo Shutter
SRI #6
Cetco Puregold Medium Bentonite Chips
2% Bentonite-Cement Grout
Well Name EW-1C
2.5
M. McLeod 7129149.100
None
n/a
+1.87
44.6
41
36
0
LOGGED BY
n/a
44.6
59.6
65
41
36
STATIC WATER ELEVATION
65.0 ft. bgs
SAMPLING METHODS
Project Number 1770027.00
EAST
953 Eloise St., South Lake Tahoe, 5 feet Southwest of Pilot Boring
FT.
FT.
FT.
FT.
FT.
FT.
TO
TO
TO
TO
TO
TO
FROM
FROM
FROM
FROM
FROM
FROM
DRILLER
DRILL BIT(S) SIZE
STAND PIPE FT.
Project Name South Tahoe PUD
NORTH
TOTAL DEPTH
DATE COMPLETED
SURFACE HOUSING
6/25/18 6/27/18
2101926.910
X
Well cap
Stand pipe
Boring & Well Construction Log
F-40.1
(6-87) (3-88) (8-90)
Penetr.Resist.Blows/6"
DrillDepth(Feet)
USCSLog Lithology Color SAMPLE DESCRIPTION and DRILLING REMARKSRecovery
(Feet)
1 2OFSHEET
Type& No.
SAMPLES WELL CONSTRUCTION
Kennedy/Jenks Consultants
BORING & WELL CONSTRUCTION 1770027.00.GPJ KENNEDY JENKS.GDT 11/16/185
10
15
20
25
30
35
WELL GRADED SAND CONT'D
SANDY SILT (ML) YELLOWISH BROWN OVERALL,MIXED LAYERS OF SAND WITH SILT, AND SMALLAMOUNT OF CLAY; SAND IS MAINLY FINE WITH
STREAKS OF 10YR 5/8 OXIDATION, SOFT, NOPLASTICITY
GRADES TO ALTERNATING LAYERS OF SILTYSAND AND POORLY GRADED SAND (SM) SAND ISMAINLY ~90% FINE GRAINED SAND, WITH ~10% SILT,
LOOSE, WET
(AQUIFER ZONE TKZ5) POORLY GRADED SAND(SP) LIGHT YELLOWISH BROWN OVERALL, ~70-80%
MEDIUM GRAINED SAND, ~20-30% FINE GRAINEDSAND, DENSE, WET
(AQUIFER ZONE TKZ5) WELL GRADED SAND (SW)YELLOWISH BROWN OVERALL, ~10% SUBROUNDEDCOARSE GRAINED SAND, ~30% MEDIUM GRAINED
SAND, ~60% MEDIUM GRAINED SAND, DENSE, WET
(AQUIFER ZONE TKZ5) POORLY GRADED SAND
(SP) YELLOWISH BROWN OVERALL, BASED UPONGRADATION TESTS AT 44-46 FT. AND 46-48 FT.:0.2-0.1% FINE GRAVEL, 3.7-3.6% COARSE GRAINED
SAND, 37% MEDIUM GRAINED SAND, 50.9-24.0% FINEGRAINED SAND, 8.1-10.3% SILT, VERY DENSE, WET
50 FT. COLOR CHANGES SLIGHTLY, MATERIALBECOMES DENSER
54 FT. THIN SUBHORIZONTAL LAYER OFFINE-GRAINED SILTY SAND
55.5 FT. SOME MEDIUM GRAINED FELDSPAR GRAINS
(AQUIFER ZONE TKZ5) WELL GRADED SAND (SW)LIGHT YELLOWISH BROWN OVERALL, TR.
SUBROUNDED COARSE GRAINED SAND, ~10-20%MEDIUM GRAINED SAND QUARTZ AND FELDSPAR,
~70-80% FINE GRAINED SAND INCLUDING MICA,DENSE, WET
(AQUIFER ZONE TKZ5) POORLY GRADED SAND
(SP) YELLOWISH BROWN OVERALL, BASED UPONGRADATION TESTS AT 64-66 FT.: 1.2% COARSEGRAINED SAND, 30.7% MEDIUM GRAINED SAND,
61.8% FINE GRAINED SAND, 6.3% SILT, MASSIVE,DENSE, WET
NOTES
1. SOIL DESCRIPTION AND SAMPLES FROM EW-1 PILOT HOLE CORE
2. EW-1 PILOT HOLE WAS DRILLED TO 150 FT.
3. EW-1C LOCATED APPX. 5 FEET SOUTHWEST OF EW-1 PILOT HOLE
4. ALL CONTACTS APPROXIMATE
5. BGS: BELOW GROUND SURFACE
6. COLOR DESIGNATION IN ACCORDANCE WITH THE MUNSELL SOIL COLOR CHARTS(KOLLMORGEN INSTRUMENTS CORPORATION, 1990)
7. SOIL CLASSIFIED IN ACCORDANCE WITH THE UNIFIED SOIL CLASSIFICATION SYSTEM, ASTMD-2488-93
8. TOP OF STEEL STANDPIPE SURVEYED ON 20 AUGUST 2018
10YR5/4
10YR 6/4
10YR5/4
10YR4/4
10YR6/4
10YR5/4
6-in. SCH80PVC ThreadedBlank Casing
Bentonite Seal
Centralizer
SRI #6 Gravel
Stainless SteelStandard Flo
Shutter Screen0.050-in.opening
Centralizer
SCH 80 PVCSump
SW
ML
SM
SP
SW
SP
SW
SP
Project Name South Tahoe PUD Project Number 1770027.00 Well Name EW-1C
Boring & Well Construction Log
F-40.1
(6-87) (3-88) (8-90)
Penetr.Resist.Blows/6"
DrillDepth(Feet)
USCSLog Lithology Color SAMPLE DESCRIPTION and DRILLING REMARKSRecovery
(Feet)
2 2OFSHEET
Type& No.
SAMPLES WELL CONSTRUCTION
Kennedy/Jenks Consultants
BORING & WELL CONSTRUCTION 1770027.00.GPJ KENNEDY JENKS.GDT 11/16/1840
45
50
55
60
65
State of California
Well Completion Report
Form DWR 188 Submitted 11/8/2018
WCR2018-010218
Owner's Well Number Date Work Began EW-1B 04/29/2018 Date Work Ended 05/04/2018
Local Permit Agency Environmental Management Department - South Lake Tahoe Office
Secondary Permit Agency Permit Number 7078 Permit Date 04/19/2018
Well Location
953 Eloise AVE Address
South Lake Tahoe City 96150Zip El DoradoCounty
38 Latitude 55 0.3288
Deg.Min.Sec.
N -120Longitude 0 17.1287
Deg.Min.Sec.
W
Dec. Lat. 38.916758 Dec. Long. -120.004758
Vertical Datum Horizontal Datum WGS84
Location Accuracy Location Determination Method
023-301-09-100APN
12 NTownship
18 ERange
05Section
Mount DiabloBaseline Meridian
Ground Surface Elevation
Elevation Accuracy
Elevation Determination Method
Geologic Log - Free Form
Depth from
Surface
Feet to Feet
Description
0 8 POORLY GRADED SAND (SP) YELLOWISH BROWN OVERALL, TR. SCATTERED SUBROUNDED COARSE GRAINED SAND, ~50%
MEDIUM GRAINED SAND,
~50% FINE GRAINED SAND, LOOSE, WET
8 10 POORLY GRADED SAND (SP) VERY DARK GRAYISH BROWN OVERALL, TR. COARSE GRAINED SAND,
~80-90% FINE GRAINED SAND, ~10% SILT, WET
10 15 WELL GRADED SAND (SW) DARK YELLOWISH BROWN OVERALL, TR. FINE GRAVEL, ~10-15%COARSE GRAINED SAND, ~50%
MEDIUM GRAINED SAND, ~40% FINE GRAINED SAND
15 19 WELL GRADED SAND WITH SILT (SW) DARK YELLOWISH BROWN OVERALL, TR. FINE GRAVEL, TR. COARSE GRAINED SAND,
~40% MEDIUM GRAINED SAND, ~40% FINE GRAINED SAND, ~10-15%SILT, VERY DENSE
19 25 WELL GRADED SAND WITH GRAVEL (SW) GRAYISH BROWN OVERALL, TR. COBBLES, ~10%SUBROUNDED GRAVEL TO 1-INCH,
~10% COARSE GRAINED SAND, ~60% FINE GRAINED SAND, ~10%SILT, VERY DENSE AND COHESIVE
19 FT. COLOR INCLUDES PALE BROWN
25 30 POORLY GRADED SAND (SP) PALE BROWN TO LIGHT YELLOWISH BROWN, ~100% FINE GRAINED SAND, VERY DENSE
20.5 - 21 FT. SOME COARSE GRAINED SAND AND MEDIUM GRAINED SAND
30 34 SANDY SILT (ML) LBG AND YELLOWISH BROWN,
~25-50% FINE GRAINED SAND INCLUDING MICA,
~50% SILT, VERY STIFF, NO PLASTICITY
25 FT. UP TO ~50% FINE GRAINED SAND
Well Owner (must remain confidential pursuant to Water Code 13752)
SOUTH LAKE TAHOE PUBLIC UTILITY DISTRICT, Name
Mailing Address 1275 Meadow Crest Drive
South Lake Tahoe City CAState 96150Zip
Planned Use and Activity
Planned Use
Activity
Water Supply Public
New Well
Borehole Information
Drilling Method
Orientation
Total Depth of Boring 38
Sonic
Vertical
38 Total Depth of Completed Well
Drilling Fluid None
Feet
Feet
Specify
Water Level and Yield of Completed Well
Depth to first water
Depth to Static
Water Level
Estimated Yield*
Test Length
*May not be representative of a well's long term yield.
(Feet below surface)
(Feet)
(GPM)
(Hours)
Date Measured
Test Type
Total Drawdown (feet)
Page 1 of 2 Form DWR 188 rev. 12/19/2017
34 38 WELL GRADED SAND (SW) YELLOWISH BROWN OVERALL, BASED UPON GRADATION TESTS AT 33-35 FT. AND 35-37 FT.: 1.4 -
9.6% FINE GRAVEL, 10.5 -17.1% COARSE GRAINED SAND, 62.0 - 43.3% MEDIUM GRAINED SAND, 20.5-22.9% FINE GRAINED
SAND, 5.6-7.1% SILT, DENSE, WET, APPEARANCE OF HIGHLY WEATHERED GRANITIC CLASTS TO COBBLE SIZE, POSS.
WEATHERED IN PLACE
Other Observations:
Certification Statement
I, the undersigned, certify that this report is complete and accurate to the best of my knowledge and belief
Name CASCADE DRILLING L P
Person, Firm or Corporation
P O BOX 1184 WOODINVILLE 98072WA
Address City State Zip
Signed electronic signature received
C-57 Licensed Water Well Contractor
11/08/2018
Date Signed
938110
C-57 License Number
DWR Use Only
CSG #State Well Number Site Code Local Well Number
N
Latitude Deg/Min/Sec Longitude Deg/Min/Sec
TRS:
APN:
W
Borehole Specifications
Depth from
Surface
Feet to Feet
Borehole Diameter (inches)
0 38 10.75
Attachments
003 ew-1b.pdf - Well Construction Diagram
Casings
Casing
#
Depth from Surface
Feet to Feet Casing Type Material Casings Specificatons
Wall
Thickness
(inches)
Outside
Diameter
(inches)
Screen
Type
Slot Size
if any
(inches)
Description
1 0 26 Blank PVC N/A 1.315 6 Sch 80
1 26 36 Screen Stainless
Steel
Grade: 304 Stainless
Steel
1.315 6 Shutter 0.05
1 36 38 Blank PVC N/A 1.315 6 Sch 80
Annular Material
Depth from
Surface
Feet to Feet
Fill Fill Type Details Filter Pack Size Description
0 21 Cement Other Cement 2% bentonite-cement grout
21 25 Bentonite Other Bentonite Puregold medium bentonite chips
25 38 Filter Pack Other Gravel Pack SRI #6 filter pack
Page 2 of 2 Form DWR 188 rev. 12/19/2017
State of California
Well Completion Report
Form DWR 188 Submitted 11/8/2018
WCR2018-010214
Owner's Well Number Date Work Began EW-1C 04/29/2018 Date Work Ended 05/04/2018
Local Permit Agency Environmental Management Department - South Lake Tahoe Office
Secondary Permit Agency Permit Number 7078 Permit Date 04/19/2018
Well Location
953 Eloise AVE Address
South Lake Tahoe City 96150Zip El DoradoCounty
38 Latitude 55 0.3288
Deg.Min.Sec.
N -120Longitude 0 17.1287
Deg.Min.Sec.
W
Dec. Lat. 38.916758 Dec. Long. -120.004758
Vertical Datum Horizontal Datum WGS84
Location Accuracy Location Determination Method
023-301-09-100APN
12 NTownship
18 ERange
05Section
Mount DiabloBaseline Meridian
Ground Surface Elevation
Elevation Accuracy
Elevation Determination Method
Geologic Log - Free Form
Depth from
Surface
Feet to Feet
Description
0 8 POORLY GRADED SAND (SP) YELLOWISH BROWN OVERALL, TR. SCATTERED SUBROUNDED COARSE GRAINED SAND, ~50%
MEDIUM GRAINED SAND,
~50% FINE GRAINED SAND, LOOSE, WET
8 10 POORLY GRADED SAND (SP) VERY DARK GRAYISH BROWN OVERALL, TR. COARSE GRAINED SAND, ~80-90% FINE GRAINED
SAND, ~10% SILT, WET
10 13 WELL GRADED SAND (SW) DARK YELLOWISH BROWN OVERALL, TR. FINE GRAVEL, ~10-15%COARSE GRAINED SAND, ~50%
MEDIUM GRAINED SAND, ~40% FINE GRAINED SAND
13 16 WELL GRADED SAND WITH SILT (SW) DARK YELLOWISH BROWN OVERALL, TR. FINE GRAVEL, TR. COARSE GRAINED SAND,
~40% MEDIUM GRAINED SAND, ~40% FINE GRAINED SAND, ~10-15%SILT, VERY DENSE
16 20 WELL GRADED SAND WITH GRAVEL (SW) GRAYISH BROWN OVERALL, TR. COBBLES, ~10%SUBROUNDED GRAVEL TO 1-INCH,
~10% COARSE GRAINED SAND, ~60% FINE GRAINED SAND, ~10%SILT, VERY DENSE AND COHESIVE
19 FT. COLOR INCLUDES PALE BROWN
20 23 POORLY GRADED SAND (SP) PALE BROWN TO LIGHT YELLOWISH BROWN, ~100% FINE GRAINED SAND, VERY DENSE
20.5 - 21 FT. SOME COARSE GRAINED SAND AND MEDIUM GRAINED SAND
23 26 SANDY SILT (ML) LBG AND YELLOWISH BROWN,
~25-50% FINE GRAINED SAND INCLUDING MICA,
~50% SILT, VERY STIFF, NO PLASTICITY
25 FT. UP TO ~50% FINE GRAINED SAND
Well Owner (must remain confidential pursuant to Water Code 13752)
SOUTH LAKE TAHOE PUBLIC UTILITY DISTRICT, Name
Mailing Address 1275 Meadow Crest Drive
South Lake Tahoe City CAState 96150Zip
Planned Use and Activity
Planned Use
Activity
Water Supply Public
New Well
Borehole Information
Drilling Method
Orientation
Total Depth of Boring 65
Sonic
Vertical
65 Total Depth of Completed Well
Drilling Fluid None
Feet
Feet
Specify
Water Level and Yield of Completed Well
Depth to first water
Depth to Static
Water Level
Estimated Yield*
Test Length
*May not be representative of a well's long term yield.
(Feet below surface)
(Feet)
(GPM)
(Hours)
Date Measured
Test Type
Total Drawdown (feet)
Page 1 of 3 Form DWR 188 rev. 12/19/2017
26 38 WELL GRADED SAND (SW) YELLOWISH BROWN OVERALL, BASED UPON GRADATION TESTS AT 33-35 FT. AND 35-37 FT.: 1.4 -
9.6% FINE GRAVEL, 10.5 -17.1% COARSE GRAINED SAND, 62.0 - 43.3% MEDIUM GRAINED SAND, 20.5-22.9% FINE GRAINED
SAND, 5.6-7.1% SILT, DENSE, WET, APPEARANCE OF HIGHLY WEATHERED GRANITIC CLASTS TO COBBLE SIZE, POSS.
WEATHERED IN PLACE
38 42 SANDY SILT (ML) YELLOWISH BROWN OVERALL, MIXED LAYERS OF SAND WITH SILT, AND SMALL AMOUNT OF CLAY; SAND IS
MAINLY FINE WITH STREAKS OF 10YR 5/8 OXIDATION, SOFT, NO PLASTICITY
42 50 SAND AND POORLY GRADED SAND (SM) SAND IS MAINLY ~90% FINE GRAINED SAND, WITH ~10% SILT, LOOSE, WET
POORLY GRADED SAND (SP) LIGHT YELLOWISH BROWN OVERALL, ~70-80% MEDIUM GRAINED SAND, ~20-30% FINE GRAINED
SAND, DENSE, WET
WELL GRADED SAND (SW) YELLOWISH BROWN OVERALL, ~10% SUBROUNDED COARSE GRAINED SAND, ~30% MEDIUM
GRAINED SAND, ~60% MEDIUM GRAINED SAND, DENSE, WET
50 57 POORLY GRADED SAND (SP) YELLOWISH BROWN OVERALL, BASED UPON GRADATION TESTS AT 44-46 FT. AND 46-48 FT.: 0.2
-0.1% FINE GRAVEL, 3.7-3.6%COARSE GRAINED SAND, 37% MEDIUM GRAINED SAND, 50.9-24.0% FINE GRAINED SAND, 8.1-
10.3%SILT, VERY DENSE, WET
50 FT. COLOR CHANGES SLIGHTLY, MATERIAL BECOMES DENSER
54 FT. THIN SUBHORIZONTAL LAYER OF
FINE-GRAINED SILTY SAND
55.5 FT. SOME MEDIUM GRAINED FELDSPAR GRAINS
57 60 WELL GRADED SAND (SW) LIGHT YELLOWISH BROWN OVERALL, TR. SUBROUNDED COARSE GRAINED SAND, ~10-20%
MEDIUM GRAINED SAND QUARTZ AND FELDSPAR, ~70-80% FINE GRAINED SAND INCLUDING MICA, DENSE, WET
60 65 SAND INCLUDING MICA, DENSE, WET
POORLY GRADED SAND (SP) YELLOWISH BROWN OVERALL, BASED UPON GRADATION TESTS AT 64-66 FT.: 1.2% COARSE
GRAINED SAND, 30.7% MEDIUM GRAINED SAND, 61.8% FINE GRAINED SAND, 6.3%SILT, MASSIVE, DENSE, WET
Other Observations:
Casings
Casing
#
Depth from Surface
Feet to Feet Casing Type Material Casings Specificatons
Wall
Thickness
(inches)
Outside
Diameter
(inches)
Screen
Type
Slot Size
if any
(inches)
Description
1 0 45 Blank PVC N/A 1.315 6 Sch 80
1 45 60 Screen Stainless
Steel
Grade: 304 Stainless
Steel
1.315 6 Shutter 0.05
1 60 65 Blank PVC N/A 1.315 6 Sch 80
Annular Material
Depth from
Surface
Feet to Feet
Fill Fill Type Details Filter Pack Size Description
0 36 Cement Other Cement 2% bentonite-cement grout
36 41 Bentonite Other Bentonite Puregold medium bentonite chips
41 65 Filter Pack Other Gravel Pack SRI #6 filter pack
Page 2 of 3 Form DWR 188 rev. 12/19/2017
Certification Statement
I, the undersigned, certify that this report is complete and accurate to the best of my knowledge and belief
Name CASCADE DRILLING L P
Person, Firm or Corporation
P O BOX 1184 WOODINVILLE 98072WA
Address City State Zip
Signed electronic signature received
C-57 Licensed Water Well Contractor
11/08/2018
Date Signed
938110
C-57 License Number
DWR Use Only
CSG #State Well Number Site Code Local Well Number
N
Latitude Deg/Min/Sec Longitude Deg/Min/Sec
TRS:
APN:
W
Borehole Specifications
Depth from
Surface
Feet to Feet
Borehole Diameter (inches)
0 65 10.75
Attachments
004 EW-1C.pdf - Well Construction Diagram
Page 3 of 3 Form DWR 188 rev. 12/19/2017
80
Baseline Groundwater Analytical Results Summary
Source
Screen
Depth
Date
ID# PCE cis-1, 2-DCE TCE MTBE TPH- DRO Benzene CCl4 Chloro- benzene Chloro- form 1,4- Dichloro- benzene 1,2- Dichloro- ethane 1,1- Dichloro- ethylene Vinyl chloride feet bgs ug/L ug/L ug/L ug/L mg/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L
Baseline Groundwater Samples
MW-4A 15-25 05/02/18 AG61178 1.5 <0.5 <0.5 <0.2 - <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
MW-4B 35-50 05/02/18 AG61179 64 0.8 2.3 <0.2 - <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
MW-4C 59-79 05/02/18 AG61180 2.7 <0.5 <0.5 <0.2 - <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
MW-7C 70-80 05/02/18 AG61181 3.4 0.6 <0.5 <0.2 - <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
MW-7D 120-140 05/02/18 AG61182 14 <0.5 <0.5 <0.2 - <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
MW-10B 35-50 05/02/18 AG61183 <0.5 <0.5 <0.5 <0.2 - <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
MW-10C 65-80 05/02/18 AG61184 <0.5 <0.5 <0.5 <0.2 - <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
EW-4D 120-140 05/02/18 AG61185 <0.5 <0.5 <0.5 <0.2 - <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
81
Moisture and Permeameter Test Results Summary
MOISTURE TEST - ASTM D7263(B)
Depth Interval
Dry Density
Moisture
Content
Soil Classification
Ft. bgs(a)
Pounds per Cubic
Foot
%
Kennedy Jenks Log
STPUD Log
24-24.5 119.1 11.7 Sandy Silt Silt 38.5-39 109.2 18.9 Sandy Silt Clayey Sand 39-39.5 110.2 16.3 96-98 79.9 27.9 Clay Clay 150 115 16.3 Silty Sand to Sandy Silt Silt Average 106.7 18.2
33-35 87.4 10.4 Well Graded Sand Poorly Graded Sand with
Silt 35-37 78.2 8.4 44-46 92.9 20.4 Poorly Graded sand Poorly Graded Fine Sand
with Silt 46-48 83.1 17.3 64-66 79 17.4 Poorly Graded Sand Poorly Graded Sand 122-124 104.4 15.5 Well Graded Sand Well Graded Gravelly
Sand Average 87.5 14.9
FIXED WALL HYDRAULIC CONDUCTIVITY TEST - USBR 5600-89
Depth Interval Hydraulic Conductivity Soil Classification
Ft. bgs Centimeters/Second Kennedy Jenks Log STPUD Log
33-35 1.38E-03 Well Graded Sand Poorly Graded Sand with
Silt 35-37 4.12E-04 44-46 1.82E-06
Poorly Graded Sand
Poorly Graded Fine Sand
with Silt 46-48 1.06E-05 46-48 Repeat 4.59E-06 64-66 5.78E-05 Poorly Graded Sand Poorly Graded Sand 122-124 7.42E-05 Well Graded Sand Well Graded Gravelly
Sand Average: 2.77E-04
FLEX WALL HYDRAULIC CONDUCTIVITY TEST - ASTM D5084
Depth Interval Hydraulic Conductivity Soil Classification Ft. bgs Centimeters/Second Kennedy Jenks Log STPUD Log 24-24.5, 25-25.5 Comb. 1.10E-04 Sandy Silt Silt 38.5-39 3.50E-08 Sandy Silt Clayey Sand 39-39.5 8.33E-05 96-98 2.86E-07 Clay to Silty Clay Clay Average 4.84E-05
(a) Ft. bgs = feet below ground surface
(b) All tests conducted by Geo-Logic Associates
82
Aquifer test site details and pressure transducer settings. Site ID Distance/Direction from pumping well Levelogger LT Serial # Sample Rate (minutes) Start Time Stop Time Nominal Casing Diameter (in.) Top of Screen (bgs) Bottom of Screen (ft bgs) Total Depth (ft bgs) Depth to Water (ft bgs) PXD Setting (ft bgs) Head (ft H2O) EW-1C Pumping
Well
F30 32011094 2 7/6/2018:
18:00
7/16/2018:
8:06
6 44 59 64 21.48 50 28.52
EW-1B 7’/south F30 32011094 2 7/6/2018:
18:00
7/14/2018:
9:10
6 26 36 38 15.6 37.5 21.9
EW-1B
atm
7’/south F5 12044990 2 7/6/2018:
18:00
7/14/2018:
9:04
6 26 36 38 15.6 5 NA
MW-XA 16’/east F5 12011448 2 7/6/2018:
18:00
7/14/2018:
9:28
2 5 15 15 4.98 9 4.02
MW-4A 106’/south F30 112086766 2 7/6/2018:
18:00
7/14/2018:
9:50
2 15 25 25 4.88 20 15.12
MW-4B 106’/south F30 112086772 2 7/6/2018:
18:00
7/14/2018:
9:34
2 35 50 50 9.33 35 25.67
MW-4C 105’/south F30 112086777 2 7/6/2018:
18:00
7/14/2018:
9:42
2 59 79 79 12.13 35 22.87
83
EW-1 Water Quality Data
Source
Screen
Depth feet
b
Date
ID#
Depth
f
Temp
pH
EC
/
D.O.
/
Turb
PCE
/
cis-1,2-
DCE
/
TCE
/
MTBE
/
TPH-
DRO
/
Ben-
zene
/
CCl4
/ Pilot Boring EW-1
30-35 05/01/18 AG61161 26.2 11.0 5.08 522 3.23 26 30.7 <0.5 0.8 <0.2 <0.5 <0.5 <0.5 Pilot Boring EW-1 Zone
41-51 05/02/18 AG61175 37.9 11.9 5.03 558 2.38 26 66 <0.5 2.8 <0.2 <0.5 112 <0.5 Pilot Boring EW-1 Zone
60-70 05/03/18 AG61192 63.2 12.6 5.17 381 8.38 54 1.5 <0.5 <0.5 <0.2 <0.5 <0.5 <0.5 Pilot Boring EW-1 Zone
119-124 05/05/18 AG61207 25.3 16.0 7.42 228 2.04 299 <0.5 <0.5 0.6 <0.2 <0.5 <0.5 <0.5 Well EW-1C Constant Rate Test Well EW-1C: (1) at 1 hr 44.6-59.6 07/11/18 AG62277 - 12.0 6.00 566 - - 64 1.1 3.9 <0.2 - <0.5 <0.5 Well EW-1C: (2) at 12
44.6-59.6 07/11/18 AG62282 - 13.6 6.14 568 - - 62 1.0 3.5 <0.2 - <0.5 <0.5 Well EW-1C: (3) at 24
44.6-59.6 07/12/18 AG62283 - 12.3 6.17 585 - - 62 1.0 3.8 <0.2 - <0.5 <0.5 Well EW-1C: (4) at 72
44.6-59.6 07/13/18 AG62306 - 12.6 6.27 575 - - 59 1.2 2.5 <0.2 <0.5 <0.5 <0.5
Source
Screen
h
Date
Chloro-
b
Chloro-
f
1,4-
Dichloro-
b
1,2-
Dichloro-
h
1,1-
Dichloro-
hl
Vinyl
hl d
TDS
Chloride
NO3-N
SO4
feet bgs ug/L ug/L ug/L ug/L ug/L ug/L mg/L mg/L mg/L mg/L Pilot Boring EW-1
30-35 05/01/18 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 328 123 1.08 6.90 Pilot Boring EW-1 Zone
41-51 05/02/18 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 430 149 1.36 6.43 Pilot Boring EW-1 Zone
60-70 05/03/18 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 278 87.8 0.456 3.91 Pilot Boring EW-1 Zone
119-124 05/05/18 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 154 25.1 0.109 8.45 Well EW-1C Constant Rate Test Well EW-1C: (1) at 1 hr 44.6-59.6 07/11/18 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 - - - - Well EW-1C: (2) at 12
44.6-59.6 07/11/18 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 - - - - Well EW-1C: (3) at 24
44.6-59.6 07/12/18 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 - - - - Well EW-1C: (4) at 72
44.6-59.6 07/13/18 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 400 136 2.28 5.76 <--------Alkalinity------->
Source
Screen
Date
HCO
CO3 OH Total Al As Cd Cr Cu Mn Se U Zn Boro
Ca Fe Mg K Na feet bgs mg/L mg/L mg/L mg/L pCi/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L mg/L mg/L ug/L mg/L mg/L mg/L Pilot Boring EW-1
30-35 05/01/18 46.1 0 0 46.1 <20 <1 <0.5 <1 2.21 134 <5 - 111 <0.05 38.6 0.05 8.83 1.80 36.8 Pilot Boring EW-1 Zone
41-51 05/02/18 54.9 0 0 54.9 3000 1.34 <0.5 2.98 7.54 104 <5 - 71.6 <0.05 52.7 2.81 13.4 2.16 34.8 Pilot Boring EW-1 Zone
60-70 05/03/18 46.4 0 0 46.4 <20 <1 <0.5 <1 <2 35.1 <5 - 32.1 <0.05 31.6 0.08 7.15 1.44 25.2 Pilot Boring EW-1 Zone
119-124 05/05/18 69.1 1.98 0 71.1 90 3.28 <0.5 <1 <2 121 <5 - <20 <0.05 12.0 0.11 4.83 2.14 25.5 Well EW-1C Constant Rate Test
Well EW-1C: (1) at 1 hr 44.6-59.6 07/11/18 - - - - - - - - - - - - - - - - - - -
84
Well EW-1C: (2) at 12
44.6-59.6 07/11/18 - - - - - - - - - - - - - - - - - - - Well EW-1C: (3) at 24
44.6-59.6 07/12/18 - - - - - - - - - - - - - - - - - - - Well EW-1C: (4) at 72
44.6-59.6 07/13/18 50.5 0 0 - - - - - - - - - - - - - - - -
85
Solutions used for aquifer test analysis of the constant test results.
Solution Description Cooper and Jacob, 1946 Generalized graphical method for evaluating formation constraints (Cooper Jacob
Straight Line Method)
Theis, 1935 Constant Discharge from a fully penetrating well in a nonleaky aquifer.
Theis, 1946 Recovery test after constant discharge from a fully penetrating well in a nonleaky
aquifer.
Hantush and Jacob, 1955 Constant Discharge from a fully penetrating well in a leaky aquifer.
Hantush, 1960 Constant Discharge from a well in a leaky aquifer with storage of water in the confining
beds.
Hantush, 1964 Constant Discharge from a partially penetrating well in a leaky aquifer.
Well parameter and aquifer property inputs used for aquifer test analysis.
Well
Pumping
Rate
(gpm)
Radial
Distance
(feet)
Casing
I.D.
(feet)
Borehole
O.D.
(feet)
Screen
Top Depth
(Z in feet)
Screen
Length
(L, in feet)
Aquifer
Thickness
(D, in feet)
Kz/Kr
EW-1C 40 0 0.4688 0.8958 18 15 68 0.01 EW-1B 0 7 0.4688 0.8958 0 10 68 0.01 MW-4A 0 106 0.1667 1.00 0 3 68 0.01 MW-4B 0 106 0.1667 1.00 14 15 68 0.01 MW-4C 0 105 0.1667 0.667 37 20 68 0.01
Average values of aquifer properties calculated for analyzed wells from the constant test.
AVERAGE AQUIFER PROPERTIES
WELL
Water-
Bearing
Zone
Saturated
Thickness
(D)
Distance from
Pumping
Well (r )
TRANSMISSIVITY
(T)
STORATIVITY
(S)
HYDRAULIC
CONDUCTIVITY
(K)
(ft) (ft) (ft2/d) (ft/d) (cm/s)
EW-1C C 68 0 1,414 21 0.007335 EW-1B B 68 7 2,519 3.0 41 0.014389 MW-4A A/B 68 106 4,600 0.06382 68 0.023867 MW-4B Cu 68 106 2,593 0.00364 38 0.013452 MW-4C Cl 68 105 3,345 0.00622 49 0.017354
Water quality results for VOCs detected in time-series samples collected during the constant test.
Sample ID
Pumping
Time
(minutes)
Total
Discharge
(gallons)
PCE
(µg/L)
TCE
(µg/L)
DCE
(µg/L)
AG62277 60 2,384 64 3.9 1.1
AG62282 720 29,009 62 3.5 1.0
AG62283 1440 58,039 62 3.8 1.0
AG62306 2880 116,379 59 2.5 1.2
86
Depth to water readings and corresponding groundwater level elevations collected from South Y Area wells. Well Measuring Point Elevation (NAVD88) 10/23/2017 DTW (ft bmp) 10/23/2017 GW Elev (ft msl) 1/17/2018 DTW (ft bmp) 1/17/2018 GW Elev (ft msl) 1/31/2018 DTW (ft bmp) 1/31/2018 GW Elev (ft msl) 5/2/2018 DTW (ft bmp) 5/2/2018 GW Elev (ft msl) 7/6/2018 DTW (ft bmp) 7/6/2018 GW Elev (ft msl) 7/14/2018 DTW (ft bmp) 7/14/2018 GW Elev (ft msl) 10/25/2018 DTW (ft bmp) 10/25/2018 GW Elev (ft msl) 11/2/2018 DTW (ft bmp) 11/2/2018 GW Elev (ft msl) 5/23/2019 DTW (ft bmp) 5/23/2019 GW Elev (ft msl) Industrial #2 6306.82 28.36 6278.46 22.65 6284.17
Tata #2 6286.09 25.02 6261.07 20.53 6265.56
Clement 6282.58 34.09 6248.49 31.25 6251.33
CL-1 6278.12 30.44 6247.68 27.10 6251.02
CL-3 6278.34 22.98 6255.36 20.03 6258.31
MW-4B 6259.27 11.08 6248.19 9.44 6249.83 12.14 6247.13 12.52 6246.75 13.12 6246.15 9.15 6250.12
MW-4A 6259.11 6.39 6252.72 5.00 6254.11 6.47 6252.64 6.85 6252.26 7.92 6251.19 4.19 6254.92
MW-4C 6259.56 13.86 6245.70 12.27 6247.29 15.10 6244.46 15.57 6243.99 15.97 6243.59 12.00 6247.56
EW-1B 6262.24 15.98 6246.26 16.28 6245.96 16.96 6245.28 13.50 6248.74
EW-1C 6262.48 21.87 6240.61 23.55 6238.93 22.42 6240.06 18.81 6243.67
EW-4C 6265.04 22.28 6242.76 21.00 6244.04 24.13 6240.91 19.40 6245.64
EW-4D 6264.99 26.20 6238.79 25.20 6239.79 28.33 6236.66 25.45 6239.55
MW-10A 6264.54 15.57 6248.97 12.77 6251.77 16.65 6247.89 11.49 6253.05
MW-10B 6264.43 18.65 6245.78 16.54 6247.89 19.89 6244.54 16.32 6248.11
MW-10C 6264.56 23.90 6240.66 21.71 6242.85 24.96 6239.60 21.83 6242.73
Helen l#2 6250.18 19.60 6230.58 15.59 6234.59
MW-7D 6254.65 15.76 6238.89 18.49 6236.16 16.35 6238.30
MW-7C 6254.53 13.83 6240.70 16.78 6237.75 14.16 6240.37
LBWC 4 6249.78 14.00 6235.78 12.33 6237.45
LBWC 1 6261.44 27.00 6234.44 26.00 6235.44
LBWC 2 6251.45 17.00 6234.45 15.17 6236.28
LBWC 5 6250.77 18.00 6232.77 16.83 6233.94
TKWC 2 6237.87 3.02 6234.85 8.30 6229.57 6.19 6231.68
TKWC 3 6238.79 4.54 6234.25 11.95 6226.84 6.45 6232.34
TKWC 1 6238.18 4.35 6233.83 8.67 6229.51 6.10 6232.08
87
Zone interpretations and bottom of screen depths and elevations used for groundwater level contours.
ZONE BOS Depth (ft) BOS Elevation (ft msl)
TKZ5; Zone B < 50 > 6200 ft msl
TKZ5: Zone Cu 78 < BOS <80 6150 ft msl < BOS < 6200 ft msl
TKZ4 BOS >132 BOS < 6150 ft msl
Horizontal gradients (ihoriz) and flow directions derived from three point problem solutions.
TKZ5: Zone B
Date dh (ft) dl (ft) ihoriz Flow Direction
10/25/18 9.21 1630 0.006 N12E
05/23/19 8.19 1490 0.005 N5E
TKZ5: Zone Cu
Date dh (ft) dl (ft) ihoriz Flow Direction
10/25/18 1.85 330 0.006 N67W
05/23/19 2.36 355 0.007 N63W
TKZ4
Date dh (ft) dl (ft) ihoriz Flow Direction
10/25/18 44.02 8025 0.005 N9W
05/23/19 48.73 8040 0.006 N12W
88
Fall 2018 and spring 2019 groundwater level elevation contours for TKZ5: Zone B.
89
Fall 2018 and spring 2019 groundwater level elevation contours for TKZ5: Zone Cu.
90
Fall 2018 and spring 2019 groundwater level elevation contours for TKZ4
91
Inputs values and results from computations using the capture zone equation (Javendal & Tsang, 1986).
Parameter Description Units EW-1B EW-1C Q Discharge Rate Gpm 20 40
Kh Hydraulic Conductivity ft/d 41 43.5
I Hydraulic Gradient ft/ft 0.006 0.005
D Aquifer Thickness Ft 12 54
v Groundwater Velocity ft/min 1.71E-04 1.51E-04
Q/(Dv) Capture Zone- Maximum up-gradient width Ft 1,304 656
Q/(2*(Dv)) Capture Zone- width perpendicular to pumping well Ft 652 328
Q/(2*pi*Dv) Capture Zone- Down-gradient distance to
Stagnation Point
Ft 208 104
0.32Q/Dv Optimal distance between two extraction wells
along a line
Ft 417 210
0.4Q/Dv Optimal distance between three or more
extraction wells along a line
Ft 522 262
Contaminant mass extraction rates for EW-1C.
Contaminant
Average
Concentration
Pumping
Rate
Mass Extraction
Rate
(µg/L) (gpm) (lbs/d)
PCE 62 40 0.03
TCE 3.4 40 0.002
DCE 1.1 40 0.001
92
GROUNDWATER FATE AND TRANSPORT MODELING
Pumping rates used for the three alternatives and two hypothetical scenarios.
Alternative Description Pumping Rates (m3/d)
LBWC 1 LBWC 5 TKWC 1 TKWC 2 TKWC 3 Sunset Paloma Helen 2 Bayview Al Tahoe 2
1A Base Treatment 872.19 199.66 532.54 1,219.49 1,316.98 1,735.79 195.74 713.22 8,997.45 1,462.21
1B Base Treatment
Conservative 872.19 199.66 532.54 1,219.49 1,316.98 1,735.79 195.74 713.22 8,997.45 1,462.21
2A Targeted Pumping 199.66 872.19 532.54 1,316.98 1,219.49 1,735.79 195.74 713.22 8,997.45 1,462.21
2B Targeted Pumping
Conservative 199.66 872.19 532.54 1,316.98 1,219.49 1,735.79 195.74 713.22 8,997.45 1,462.21
3A SW Conversion 872.19 199.66 532.54 1,219.49 1,316.98 1,735.79 195.74 713.22 8,997.45 1,462.21
3B SW Conversion
Conservative 872.19 199.66 532.54 1,219.49 1,316.98 1,735.79 195.74 713.22 8,997.45 1,462.21
4 90% of GAC Capacity 389.52 3,434.13 1,458.14 2,698.24 808.56 1,165.41 131.57 478.85 6,039.43 981.75
5 90% of Well Capacity 389.52 3,434.13 1,458.14 8,830.61 808.56 353.01 39.85 145.05 1,829.36 297.38
93
PCE recharge concentration for predictive simulations and biodegradation half-lives by layer.
Alternative Description Source Term –
Future Recharge PCE
Source Term –
Future Recharge PCE
Biodegradation Half-life (years)
(mg/l) (kg/yr) Layer 1 Layer 2 Layer 3 Layer 4
1A Base Treatment 0 0 17 17 2 2
1B Base Treatment
Conservative
10 4.45 0 0 0 0
2A Targeted Pumping 0 0 17 17 2 2
2B Targeted Pumping
Conservative
10 4.45 0 0 0 0
3A SW Conversion 0 0 17 17 2 2
3B SW Conversion
Conservative
10 4.45 0 0 0 0
4 90% of GAC Capacity 0 0 17 17 2 2
5 90% of Well Capacity 0 0 17 17 2 2
Mass removed and removal rate by well for all alternatives. **Alternatives 3A and 3B simulated for WY 2019-2033.
Alternative
Description
PCE Mass Removed (0.4536 kg) or (lbs); WY 2019-
2068**
Total Extracted Groundwater
Volume; WY 2019-2068
Average PCE Mass
Removal Rate LBWC 5 TKWC 1 TKWC 2 Total (3785 m3) or (MG) (lb/MG)
Alternative 1A Baseline 54.1 68.8 224.1 347.0 9416.1 0.04
Alternative 1B Conservative Baseline 260.4 763.8 1548.3 2572.5 9416.1 0.27
Alternative 2A Targeted 204.7 60.5 232.0 497.2 13131.1 0.04
Alternative 2B Conservative Targeted 971.2 678.4 1615.0 3264.6 13131.1 0.25
Alternative 3A** SW Conversion 43.0 26.8 162.4 232.2 2824.9 0.08
Alternative 3B** Conservative SW
Conversion
189.2 224.0 1004.9 1418.1 2824.9 0.50
Alternative 4 90% of GAC capacity 697.6 48.1 249.6 995.3 36621.0 0.03
Alternative 5 90% of well capacity 626.5 16.2 506.5 1149.2 66207.1 0.02
94
Simulated year PCE concentrations drop below 4 ug/l, by well, and the number of years after 2018 each well drops below 4 ug/l for all alternatives. N.E. = Never Exceeds.
Alternative Description Year PCE < 4 µg/l Years after 2018 (PCE < 4 µg/l)
LBWC 1 LBWC 5 TKWC 1 TKWC 2 TKWC 3 LBWC 1 LBWC 5 TKWC 1 TKWC 2 TKWC 3
Alternative 1A Baseline N.E. 2040 2045 2040 N.E. N.E. 22 27 22 N.E.
Alternative 1B Conservative Baseline N.E. 2058 >2068 >2068 N.E. N.E. 40 > 50 > 50 N.E.
Alternative 2A Targeted N.E. 2038 2040 2039 N.E. N.E. 20 22 21 N.E.
Alternative 2B Conservative Targeted N.E. 2054 >2068 >2068 N.E. N.E. 36 > 50 > 50 N.E.
Alternative 3A SW Conversion N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A
Alternative 3B Conservative SW
Conversion
N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A
Alternative 4 90% of GAC capacity N.E. 2035 N.E. 2030 N.E. N.E. 17 N.E. 12 N.E.
Alternative 5 90% of well capacity N.E. 2032 N.E. 2026 N.E. N.E. 14 N.E. 8 N.E.
95
Simulated hydraulic conductivities for model layers 1 and 2.
96
Simulated hydraulic conductivities for model layer 3.
97
Simulated hydraulic conductivities for model layer 4.
98
Areal recharge rates applied over model domain, as taken from Carroll, 2016
99
Locations of steady-state pumping wells.
100
Locations of transient pumping wells.
101
Years after 2018 until simulated PCE concentrations drop below 4 ug/l, by alternative and well. Alternative 3A and 3B
simulations are not long enough to show declines below 4 ug/l. Concentrations at TKWC 1 never exceed 4 ug/l in Alternatives
4 and 5.
Years to PCE < 4 ug/l
102
Mass extracted (in kilograms) by alternative and well. Note Alternative 3A simulation was run for only 15 years, while all
others are run for 50 years.
Mass Extracted, Kg
103
Mass extracted (in kilograms) by alternative and well. Note Alternative 3A simulation was run for only 15 years, while all
others are run for 50 years
Mass Extracted (kg)
104
Pumping rates used for the three alternatives and two hypothetical scenarios
Alternative Description Pumping Rates (m3/d)
LBWC 1 LBWC 5 TKWC 1 TKWC 2 TKWC 3 Sunset Paloma Helen 2 Bayview Al Tahoe 2 EW-1
1A Base Treatment 872.19 199.66 532.54 1,219.49 1,316.98 1,735.79 195.74 713.22 8,997.45 1,462.21 0
1B Base Treatment
Conservative
872.19
199.66
532.54
1,219.49
1,316.98
1,735.79
195.74
713.22
8,997.45
1,462.21
0 2A, Option 1 Targeted Pumping 199.66 872.19 532.54 1,219.49 1,316.98 1,735.79 195.74 713.22 8,997.45 1,462.21 0
2B, Option 1 Targeted Pumping
Conservative
199.66
872.19
532.54
1,219.49
1,316.98
1,735.79
195.74
713.22
8,997.45
1,462.21
0 2A, Option 2 SW Conversion 199.66 872.19 532.54 1,219.49 1,316.98 1,735.79 195.74 713.22 8,997.45 1,462.21 872.17
2B, Option 2 SW Conversion
Conservative
199.66
872.19
532.54
1,219.49
1,316.98
1,735.79
195.74
713.22
8,997.45
1,462.21
872.17 Note: To convert pumping rates from cubic meter per day (m3/d) into gallons per minute (gpm) multiply by 0.1835
PCE recharge concentration for predictive simulations and biodegradation half-lives by layer.
Alternative
Description
Source Term – Future
Recharge PCE
Source Term – Future
Recharge PCE
Biodegradation Half-life (years)
(mg/l) (kg/yr) Layer 1 Layer 2 Layer 3 Layer 4
1A Base Treatment 0 0 17 17 2 2
1B Base Treatment
Conservative
10 4.45 0 0 0 0
2A, Option 1 LBWC 5 Lead 0 0 17 17 2 2
2B, Option 1 LBWC 5 Lead
Conservative
10 4.45 0 0 0 0
2A, Option 2 LBWC 5 Lead / EW-1 0 0 17 17 2 2
2B, Option 2 LBWC 5 Lead / EW-1
Conservative
10 4.45 0 0 0 0
105
Mass removed and removal rate by well for all alternatives
Alternative
Description
PCE Mass Removed (0.4536 kg) or (lbs); WY 2019-2068 Total Extracted
Groundwater Volume; WY
2019-2068
Average PCE Mass
Removal Rate
LBWC 5 TKWC 1 TKWC 2 EW-1 Total (3785 m3) or (MG) (lb/MG)
1A Baseline 54.1 68.8 224.1 N/A 347.0 9416.1 0.04
1B Conservative Baseline 260.4 763.8 1548.3 N/A 2572.5 9416.1 0.27
2A, Option 1 LBWC 5 Lead 205.9 61.8 217.5 N/A 485.2 12660.7 0.04
2B, Option 1 LBWC 5 Lead
Conservative
979.5 692.1 1519.1 N/A 3190.7 12660.7 0.25
2A, Option 2 LBWC 5 Lead / EW-1 140.0 47.8 181.5 449.0 818.3 16868.6 0.05
2B, Option 2 LBWC 5 Lead / EW-1
Conservative
698.7 568.9 1364.9 1503.6 4136.1 16868.6 0.24
Simulated year PCE concentrations drop below 4 ug/l, by well, and the number of years after 2018 each well drops below 4 ug/l for all alternatives. N.E. = Never Exceeds
4 ug/l.
Alternative Description Year PCE < 4 µg/l Years after 2018 (PCE < 4 µg/l)
LBWC 1 LBWC 5 TKWC 1 TKWC 2 TKWC 3 LBWC 1 LBWC 5 TKWC 1 TKWC 2 TKWC 3
1A Baseline N.E. 2040 2045 2040 N.E. N.E. 22 27 22 N.E.
1B Conservative Baseline N.E. 2058 >2068 >2068 N.E. N.E. 40 >50 >50 N.E.
2A, Option 1 LBWC 5 Lead N.E. 2038 2041 2039 N.E. N.E. 20 23 21 N.E.
2B, Option 1 LBWC 5 Lead
Conservative
N.E. 2054 >2068 >2068 N.E. N.E. 36 >50 >50 N.E.
2A, Option 2 LBWC 5 Lead / EW-1 N.E. 2033 N.E. 2036 N.E. N.E. 15 N.E. 18 N.E.
2B, Option 2 LBWC 5 Lead / EW-1
Conservative
N.E. 2046 >2068 2062 N.E. N.E. 28 >50 44 N.E.
106
Alternative 2A, Option 2. Simulated PCE plume in model layer 1 at the end of the 2068 water year
107
Alternative 2B, Option 2 (Conservative). Simulated PCE plume in model layer 1 at the end of the 2068 water year
108
Years after 2018 until simulated PCE concentrations drop below 4 ug/l, by alternative and well. Concentrations at TKWC 1
never exceed 4 ug/l in Alternative 2A, Option 2.
Years to PCE < 4 µg/l
109
Mass extracted (in kilograms) by alternative and well. Note EW-1 does not pump in Alternative 1A or Alternative 2A, Option 1
and mass extraction at that well is therefore zero
Mass Extracted (kg)
110
FEASIBILITY STUDY REPORT
Remedial Action Objectives (RAOs)
Notes:
(a) STPUD is responsible for management of the groundwater basin. Other water supply entities are the water retailers. (b) Other parties have been named as responding parties to a Cleanup and Abatement Order issued by the Water Board. (c) HVOCs = halogenated volatile organic compounds including tetrachloroethene (PCE) and its degradation products.
Line No General EPA Remedial Action Objectives
South Y Specific Remedial Action Objectives
Comments
Source: Per EPA Document 540/R-96/023: Objectives applicable for all sites with contaminated groundwater include the following:
1 Prevent exposure to contaminated ground water, above acceptable risk levels. Allow additional groundwater production without treatment
2 Prevent or minimize further migration of the contaminant plume (plume
containment).
Design and implement remedies without increasing existing volume
of groundwater impacted by HVOCs ( C ) (plume containment)
3 Prevent or minimize further migration of contaminants from source materials to
ground water (source control).
Concentration reduction to < 50 ppb at drinking water wells, mass
removal for proposed remedial measure
To avoid 97-005 permitting requirements
4 Return ground waters to their expected beneficial uses wherever practicable
(aquifer restoration).
Not applicable for South Y study
Source: Per EPA Document 540/G-88/003: Remedial Action Objectives for contaminated groundwater sites should address the following:
5 Cleanup Level Assist in overall objective of supplying water without detectable
HVOCs( C) to customers
Comply with regulatory agency requirements and directives
regarding HVOCs (C ) in groundwater
Proposition 1 Metrics of Success: Estimated mass of contaminant
removed over the projected life of the project
RAO that aims to reduce contaminant mass to reduce the cleanup burden (e.g., reduce well
head treatment duration) for downgradient receptors required to cleanup pumped water to
MCLs for distribution and consumption – maybe this amounts to some level of concentration
reduction, but still greater than MCLs in in-situ groundwater.
6 Area of Attainment Address groundwater in mid-plume area including groundwater <
100’ below ground surface with high concentrations of PCE in mid-
plume and/or replacement wells in deeper aquifer outside of the
plume
This is addressed above and likely to include the area of the plume between the source zone
and the downgradient extent of the plume
7 Restoration Time Frame Anticipated remediation time frame is 30 years or less to remove
the majority of PCE mass in groundwater in the mid-plume area cost
effectively
RAO that acknowledge STPUD’s/Water Agency’s efforts as interim and will be maintained
until such time that source control has been implemented by the RPs and groundwater
concentrations have declined to influent levels that are equal to or less than the proposed
cleanup level above)
Other South Y Specific Objectives
Preserve ability to recover HVOC( C) response costs from responsible
parties and/or state grant funding in the future
Preference for beneficial use of any extracted groundwater
resource (i.e. not disposal to sanitary sewer or storm drain)
Reduce costs (capital or long-term O&M) for groundwater remedial
wellhead treatment to retail customers
Perform community outreach and information activities regarding
HVOCs( C) in groundwater
111
Applicable or Relevant and Appropriate Requirements (ARARs)
Requirement Description Other Information
Clean Water Act (CWA)
(33 USCA
125-1-1376 and 40
CFR 100-149.
Federal act that establishes a system of national
effluent discharge standards and ocean discharge
requirements.
CWA, Section 304 Establishes water quality criteria based on the
designated or potential use of the water and
designated use of the receiving waters.
CWA, Section 404 Prohibits discharge of dredged or fill material into
wetlands without a permit. US Army Corps of
Engineers regulates activities that may physically alter
the waters of the United State.
Safe Drinking Water Act
(SDWA)/ California Code
of Regulations, Title 22
Establishes primary and secondary drinking water
standards.
California sets drinking water standards
based on Federal SDWA
Clean Air Act (42 USC
7401-7642, 40
CFR 50 – 69)
Identifies categories of industrial sources and
treatment standards. Establishes primary and
secondary ambient air standards. States develop
implementation plans for attainment of the standards.
May be applicable or relevant and
appropriate depending upon the response
action being considered. Impacts to air
quality, if any, under local air district
jurisdiction may result from the
implementation of some of the removal
Occupational Safety and
Health Act (29 CFR
1910.120 et
seq.)
Identifies permissible exposure limits (PELs) for
inhalation or dermal exposure of workers to
chemicals.
When PELs are exceeded, OSHA requires the use of
personal protective equipment or other methods to
block exposure.
Occupational Safety and Health Act (29 CFR
1910.120 et
seq.)
National Historic
Preservation Act of 1966
(NHPA) 16 USC
470 and 36 CFR 800
Established to preserve historic properties National Historic Preservation Act of 1966
(NHPA) 16 USC
470 and 36 CFR 800
112
Requirement Description Other Information
Endangered Species Act of
1973
Established to conserve endangered or threatened
species
Endangered Species Act of 1973
Hazardous Waste Control
Act (HSC, Chapter 6.5,
section
25100 et seq., 22 CCR
66260.1 et seq.)
Establishes criteria for determining waste
classification for the purposes of transportation and
land disposal of wastes in California. Regulates
treatment, storage, transportation and disposal of
substances identified as hazardous.
Hazardous Waste
Generator Requirements
(22 CCR 66262.1 et seq.)
Establishes standards applicable to generators of
hazardous waste.
Land Disposal Restrictions
(22 CCR
66268.7 et seq.)
Establishes standards for treatment and land disposal
of hazardous waste.
Stockpiling Requirements
for Contaminated Soil
(HSC section 25123.3(a)(2)
Establishes standards for stockpiling of non-RCRA
contaminated soil
California Hazardous
Substances Account Act
(HSC section 25340-
25392)
Establishes fees regarding disposal of hazardous
substances and outlines process for cleanup of
hazardous substance release sites.
Porter Cologne Water
Quality Act (23 CCR
Chapter 3,
Subchapter 15, WC
section 13000 et seq.)
Establishes the authority of the State Water Resources
Control Board and Regional Water Quality Control
Boards to protect water quality by identifying
beneficial uses of the waters of the State, establishing
water quality objectives, and regulating discharges to
is there a word missing here???waters of the state.
113
Requirement Description Other Information
Regional Water Quality
Control Board Basin Plan
Adopts narrative standards and permissible
concentrations of organic and inorganic chemicals for
surface water, groundwater, point sources and non-
point sources. Establishes beneficial uses of surface
waters and groundwater.
NPDES Permit The State Water Resources Control Board (SWRCB), as
part of the National Pollutant Discharge Elimination
System (NPDES), has adopted a statewide NPDES
General Permit for Stormwater Discharges Associated
with Construction Activity (General Permit) to address
discharges of storm water runoff from construction
projects that encompass one acre or more in total
acreage of soil disturbances.
This would be applicable for construction
activities, including demolition, clearing,
grading, excavation, soil stockpiling,
material storing, onsite staging, offsite
staging, and other land disturbance
activities.
Hazardous Waste Haulers
Act (22 CCR Chapter 30)
Governs transportation of hazardous materials in
California.
Safe Drinking Water and
Toxic Enforcement Act
(Proposition 65) (22 CCR
section 12000 et seq.)
Requires public warnings of potential exposure to
suspected carcinogens and reproductive toxins.
California Occupational
Health and Safety (8 CCR
5192)
Requires workers involved in hazardous substance
operations associated with cleanup of sites perform
the cleanup operations in accordance with Cal OSHA
health and safety requirements.
Applicable requirement for all workers who
can come into contact with contaminated
media at the Site
California Fish and Game
Code (sections 1601-1607
and 5650)
Regulates activities that involve construction within
stream channels to assure protection of fish and
wildlife. Prohibits discharges to waters of the State
that may cause adverse effects to fish, plant or bird
life.
114
Requirement Description Other Information
Tahoe Regional Planning
Agency Ordinances
Governing Exterior
Lighting, Land Use
Coverage, Building
Height/Scenic Resources
and Noise
Limits exterior lighting, impervious coverage of
property, height and aesthetics of buildings, and the
amount of noise generated during certain times of day
as defined by Community Noise Equivalency Levels
(CNEL).
115
Summary of Detailed Analysis of Refined Alternatives (20-Year Period from 2019-2038)
Criteria
Alternative 1 – No Action
Alternative 2 – Targeted Pumping – LBWC Demands with Extraction Well (a)
Alternative 3 – Conversion to Surface Water
Treatment
Option 1: Potable Reuse
Option 2: Sewer Discharge
Option 3: Sewer/Stormwater System
Discharge
Effectiveness
PCE Mass Removal 280 to 1,800 lbs 770 to 3,300 lbs 770 to 3,300 lbs 770 to 3,300 lbs 230 to 1,400 lbs
PCE Concentration Trends/
Reduction in Toxicity
• PCE concentrations remain above MCL in
LBWC 5 and TKWC 2
• PCE concentration increases to above the
MCL in TKWC 1
• PCE concentrations in LBWC 1 and TKWC
3 are not expected to rise above the MCL
• PCE concentrations have the potential to
reduce to below the MCL in LBWC 5,
TKWC 2, and R1
• PCE concentrations in LBWC 1, TKWC 1,
and TKWC 3 are not expected to rise
above the MCL
• PCE concentrations have the potential to
reduce to below the MCL in LBWC 5,
TKWC 2, and R1
• PCE concentrations in LBWC 1, TKWC 1,
and TKWC 3 are not expected to rise
above the MCL
• PCE concentrations have the potential to
reduce to below the MCL in LBWC 5,
TKWC 2, and R1
• PCE concentrations in LBWC 1, TKWC 1,
and TKWC 3 are not expected to rise
above the MCL
• PCE concentrations remain above MCL in
LBWC 5 and TKWC 2
• PCE concentration increases to above the
MCL in TKWC 1
• PCE concentrations in LBWC 1 and TKWC
3 are not expected to rise above the MCL
Short-Term Effectiveness 0 years to implement 3 to 7 years to implement (b) 3 to 7 years to implement (b) 3 to 7 years to implement (b) 15 years to implement
Long-Term Effectiveness • 3,800 MG of potable water produced
through existing infrastructure and
operations
• No additional potable supply or
improvement in water quality
Additional 2,900 MG of potable water
produced through R1 (total 6,700 MG of
potable water produced)
No additional potable water supply No additional potable water supply • Complete switch of water supply to
source not impacted by PCE – 940 MG
produced through SWTP to meet
demands
• No additional PCE treatment; PCE mass
removal ceases with conversion to
Overall Protection of
Human Health and
Environment
• No additional PCE treatment
• No reduction in exposure to PCE through
drinking water
• New PCE treatment at R1
• Additional PCE removal through LBWC 5
(lead well) and R1
• Reduction in PCE mass removed through
TKWC 1 d TKWC 2
• New PCE treatment at R1
• Additional PCE removal through LBWC 5
(lead well) and R1
• Reduction in PCE mass removed through
TKWC 1 d TKWC 2
• New PCE treatment at R1
• Additional PCE removal through LBWC 5
(lead well) and R1
• Reduction in PCE mass removed through
TKWC 1 d TKWC 2
Complete switch of water supply to source not
impacted by PCE
Compliance with ARARs No additional permitting Additional Permitting:
• Sewer discharge
• TRPA and environmental clearances
• Temporary permitting related to
construction
• New drinking water source and
potentially Policy Memo 97-005
permitting (SWRCB-DDW)
Additional Permitting:
• Sewer discharge
• TRPA and environmental clearances
• Temporary permitting related to
construction
Additional Permitting:
• Sewer discharge
• TRPA and environmental clearances
• Temporary permitting related to
construction
• NPDES permitting and mitigation for
stormwater discharge
Additional Permitting:
• Water Rights Permit modification
• Sewer discharge
• NPDES permitting and mitigation for
stormwater discharge
• TRPA, Department of Fish and Wildlife,
US Army Corps of Engineers, California
Air Resources Board and other
environmental clearances
• CTC access
• New drinking water source permitting
(SWRCB-DDW)
T i i l d
Notes:
a. Alternative 2 Options:
Option 1 – Potable reuse of water produced at R1
Option 2 – Disposal of water produced at R1 via District sewer
Option 3 – Disposal of water produced at R1 via District sewer in wet months (October through April) and via the City of South Lake Tahoe stormwater system in dry months (May through September)
116
b. Fate and Transport Model results assume PCE removal for Alternative 2 begin immediately for all wells, including new R1. To calculate PCE removal through R1 following the implementation period of 3-7 years, it is assumed that mass will be removed from the R1 site at the
same fractional rate over a 20 year period, and mass removal for R1 after 3-7 years can be estimated by scaling the total simulated mass removed at R1 in Alternative 2 to the ratio of [Alternative 1 concentration at R1 after 3-7 years] to [Alternative 2 Option 2 concentration
at R1 at start of simulation]. Using this method, mass extraction at R1 beginning in 3-7 years is estimated to be between 77.7% (beginning in 3 years) and 47.6% (beginning in 7 years) of mass extraction beginning immediately, which was estimated to be 446.6 lbs. Therefore,
mass extracted at R1 beginning at 3-7 years (for a pumping period of 13 to 17 years out of the 20-year total) is estimated to be 213 lbs to 2,559 lbs.
c. Cost Evaluation conducted over a 20-year period, the first 15 of which assumes No Action operations during design, construction, and start-up of SWTP. Therefore, Total O&M Costs are for the last five years of the Cost Evaluation period.
Cost estimates based on 2019 dollars with an accuracy range of -30% to +50%. Cost factors and assumptions are described in Section 5.4
117
Modeled Management Scenarios
Management Scenarios Description Initial Modeling
1
No Action
• Maintain current (2018) pumping strategy (lead/lag/lag-lag) for
TKWC and LBWC wells
• Produced water from LBWC 5 and TKWC 2 is treated via existing
2
Targeted
Pumping
• Use LBWC 5 and TKWC 2 as the lead wells for LBWC and TKWC,
respectively, for PCE mass removal and limit potential plume
migration towards TKWC 1, TKWC 3, and LBWC 1
3
Surface Water
Conversion
• Switch LBWC and TKWC water supply to Lake Tahoe surface
water
• Maintain current pumping strategy for time to implement
surface water treatment plant (assume 15 years)
• Produced water from LBWC 5 and TKWC 2 is treated via existing
GAC for the first 15 years
4
90% GAC
Capacity
• Pump both LBWC 5 and TKWC 2 at a rate of 90% of the existing
GAC capacity
• Maintain current pumping strategy at remaining LBWC and
TKWC wells
5
90% Well
Capacity
• Pump both LBWC 5 and TKWC 2 at a rate of 90% of the existing
well pumping capacity
• Maintain current pumping strategy at remaining LBWC and
TKWC wells
Revised Modeling Revised
Scenario 2,
Option 1
LBWC 5 Lead
• Use LBWC 5 as the lead well for hydraulic control and PCE mass
removal for LBWC. Produced water from LBWC 5 is treated via
GAC water treatment facility planned to start operating in 2021.
Revised
Scenario 2,
Option 2
LBWC 5 Lead/
R1
• Use LBWC 5 as the lead well for LBWC. Produced water from
LBWC 5 is treated via existing GAC
• Construct a new extraction well (R1) and groundwater treatment
facility at 843 Hazel Drive for to replace lost groundwater
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Results of the Modeled Management Scenarios
Management Scenarios
Total PCE Mass
Removed (a) (lbs)
Peak PCE Concentration (a)
Cleanup Time
(Years) (b) LBWC 1 LBWC 5 TKWC 1 TKWC 2 TKWC 3 Original 1 No Action 280 – 1,800 <1 23 to 96 5 to 50 14 to 108 <1 >20
2 Targeted Pumping 420 – 2,400 <1 22 to 94 4 to 44 13 to 105 <1 20 to >20
3 Surface Water
Conversion (c)
230 – 1,400 <1 23 to 96 5 to 50 14 to 108 <1 >20
4 90% GAC Capacity 940 <1 23 3 13 <1 17
5 90% Well Capacity 1,100 <1 25 3 13 <1 14 Revised Revised
Scenario 2,
Option 1
LBWC 5 Lead
420 – 2,400
<1
22 to 94
5 to 44
13 to 105
<1
20 to >20
Revised
Scenario 2,
Option 2 (d)
LBWC 5 Lead/ R1
770 – 3,300
<1
21 to 89
4 to 38
13 to 103
<1
17 to >20
Notes:
a. Over first 20-year modeling period from 2018 – 2038.
b. Cleanup time is for all 5 wells from start of 20-year modeling period beginning in 2018.
c. Management Scenario 3 assumed No Action groundwater operations for 15 years until change over to surface water treatment. Therefore, Peak PCE Concentrations would resemble Management Scenario 1
d. Fate and Transport Model results assume PCE removal for Alternative 2 begin immediately for all wells, including new R1. To calculate PCE removal through R1 following the implementation period of 3-7 years, it is assumed that mass will be removed from the R1 site at the
same fractional rate over a 20 year period, and mass removal for R1 after 3-7 years can be estimated by scaling the total simulated mass removed at R1 in Alternative 2 to the ratio of [Alternative 1 concentration at R1 after 3-7 years] to [Alternative 2 concentration at R1 at
start of simulation]. Using this method, mass extraction at R1 beginning in 3-7 years is estimated to be between 77.7% (beginning in 3 years) and 47.6% (beginning in 7 years) of mass extraction beginning immediately, which was estimated to be 446.6 lbs. Therefore, mass
extracted at R1 beginning at 3-7 years (for a pumping period of 13 to 17 years out of the 20-year total) is estimated to be 213 lbs to 2,559 lbs.
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Remedial Alternatives Selected for Detailed Analysis
Remedial Alternative Description
1 No Action Maintain existing operation with no new infrastructure changes
2 Targeted Pumping – LBWC
Demands with New Extraction
Well
Operate LBWC 5 as lead well and LBWC 1 as lag well
Operate new Extraction Well 1 as extraction well with connection
to the distribution systems for use by water purveyors in the South
Y Area.
Maintain existing operation with no new infrastructure for the
TKWC system 3 Conversion to Surface Water
Treatment Plant
Maintain the existing groundwater source operation strategy for
10-15 years with gradual conversion to use of surface water
operation strategy.
Alternative 2 Preliminary Cost Estimate (2019$, Rounded)
Option Capital Cost (a) O&M Cost (a)
1. Potable Reuse $3.6M to $7.8M (b)
(New Well, GAC/Potable Water
Treatment, Treatment Facility,
Pipeline to Sewer)
$4.6M to $9.9M over 20 years,
$200,000 - $2.0M annually (Start-up
Demonstration of treatment,
Conditional Operation, Normal
2. Discharge to Sewer $2.8M to $6.0M
(New Well, GAC Treatment,
Treatment Facility Pipeline to Sewer)
$15M to $33M over 20 years,
$770,000 - $1.7M annually
(Treatment Pilot Normal Operations) 3. Discharge to Sewer/
Stormwater System
$2.9M to $6.2M
(New Well, GAC Treatment,
Treatment Facility, Pipeline to Sewer,
Pili t St t St )
$9.4M to $20M over 20 years,
$470,000 - $1.0M annually
(Treatment Pilot, Normal Operations)
Note:
a. Cost estimates based on 2019 dollars with an accuracy range of -30% to +50%. Cost factors and assumptions are described in Section 5.4.
b. Compliance with Policy Memo 97-005 is expected to incur a cost from $400,000 - $900,00 for studies such as Drinking Water Source Assessment,
additional monitoring, and coordination with DDW.
Ranking of Remedial Alternatives – Quantifiable Criteria
Quantified Criteria
Alternative 1:
Alternative 2: Targeted Pumping (a)
Alternative 3:
Conversion to
Option 1:
Potable Reuse
Option 2: Sewer
Discharge
Option 3: Sewer/
Stormwater
System Discharge
Quantity of PCE
Removed (lbs)
280 to 1,800 770 to 3,300 770 to 3,300 770 to 3,300 230 to 1,400
Quantity of Water
Produced for
Potable Use (MG)
3,800
6,700
3,800
3,800
2,900 (GW) (b)
940 (SWTP) (c)
Additional Capital
(Rounded)/ PCE
Removed ($/lbs) (d)
No New Costs
1,100 – 10,000
850 - 7,800
880 – 8,100
No New Costs
for PCE
Removal
Additional Annual
O&M Cost
(Rounded)/ PCE
Removed ($/lbs) (d)
No New Costs
60 – 2,600
230 – 2,200
140 – 1,300
No New Costs
for PCE
Removal (c)
Notes:
a. Fate and Transport Model results assume PCE removal for Alternative 2 begin immediately for all wells, including new R1. To calculate PCE removal
through R1 following the implementation period of 3-7 years, it is assumed that mass will be removed from the R1 site at the same fractional rate over
a 20 year period, and mass removal for R1 after 3-7 years can be estimated by scaling the total simulated mass removed at R1 in Alternative 2 to the
ratio of [Alternative 1 concentration at R1 after 3-7 years] to [Alternative 2 concentration at R1 at start of simulation]. Using this method, mass
extraction at R1 beginning in 3-7 years is estimated to be between 77.7% (beginning in 3 years) and 47.6% (beginning in 7 years) of mass extraction
beginning immediately, which was estimated to be 446.6 lbs. Therefore, mass extracted at R1 beginning at 3-7 years (for a pumping period of 13 to 17
years out of the 20-year total) is estimated to be 213 lbs to 2,559 lbs.
b. From groundwater produced by wells with detectable levels of PCE (TKWC 2, TKWC 1, and LBWC 5) pumping for the assumed 15 years it would take to
design, construct, and start-up the SWTP.
c. Surface water treated and delivered to meet demands for 5 years (following 15-year implementation period of groundwater pumping).
d. Cost based on Preliminary Cost Estimates for Capital and Average Annual O&M (for 20 years) as presented in this Section. Cost estimates based on 2019
dollars with an accuracy range of -30% to +50%. Cost factors and assumptions are described in Section 5.4.
120
Summary of Preliminary Costs of Pre-Design Activities for the Preferred Remedial Alternative (2019$, Rounded)
Activity Estimated Cost (2019$) (a), (b)
R1 Test Well and Treatment Pilot $130,000 to $280,000
Policy Memo 97-005 Documentation and Permit Application $370,000 to $790,000
Site Survey and Geotechnical Investigation $50,000 to $110,000
TRPA/CEQA Environmental Documentation and Approvals $44,000 to $94,000
Funding, Maintenance, and Water Service Agreements Discussions As Needed
Total Preliminary Cost Estimate for Pre-Design Activities $500,000 to $1,100,000
Summary of Preliminary Costs of Environmental Impact Mitigation for Preferred Remedial Alternative
Environmental Impact Preliminary Estimated Cost of Mitigation (2019$)
Air Quality El Dorado County Air Quality Management District (AQMD) Fees (July 1,
2019 – June 30, 2020) (a):
• Authority to Construct Application = $393
• Filing Fee = $103
• Fugitive Dust Plans = $138
Light and Glare To be determined during design
Noise (b) • Temporary Construction Sound Walls = $6,000
• Facility Building Shell = $250/building square feet Transportation/Circulation To be determined during design/construction
Utilities To be determined during design TRPA Coverage (c) • TRPA Land Capability Application/Review = $4,964
• Coverage Purchase = $19,200 Notes:
a. From the AQMD Fee Schedule for July 1, 2019 – June 30, 2020: https://www.edcgov.us/Government/AirQualityManagement/Documents/19-
20%20AQMD%20FINAL%20BUDGET%20FOR%20WEBSITE.pdf
b. Based on PDI cost for noise control.
c. The costs listed in this table are for reference only and is not intended to encompass all mitigation requirements that may be encountered during the
development of this Alternative should it proceed to design and construction. It is assumed that during the design of this Alternative, specific permits
and other requirements will be identified and the cost for mitigation will be updated.
Summary of Preliminary Costs of Implementation for Preferred Remedial Alternative (2019$, Rounded)
Description Estimated Cost (2019$)
R1 Drilling, Construction, and Pump/Motor $330,000 to $710,000 Groundwater Treatment Facility and GAC Vessels $1,600,000 to $3,500,000 Iron and Manganese Treatment $470,000 to $1,000,000 Monitoring Network Plan and New Monitoring Well (1) $49,000 to $110,000 Contingency (25%) $620,000 to $1,300,000
Permitting/Engineering/Design/Construction Management (20%) $620,000 to $1,300,000
Total Preliminary Cost Estimate $3,700,000 to $8,000,000
Note:
Cost estimates based on 2019 dollars with an accuracy range of -30% to +50%. Cost factors and assumptions are described in Section 5.4.
Summary of Preliminary Costs of O&M for the Preferred Remedial Alternative (2019$, Rounded)
Description
Estimated Annual Cost
(2019$) (a)
Estimated 20-Year Cost
(2019$) (a) Facility O&M $130,000 to $270,000 $2,500,000 to
Policy Memo 97-005 Monitoring and
$34,000 to $73,000 $680,000 to $1,500,000
Water Quality Operations and Monitoring $47,000 to $100,000 $930,000 to $2,000,000
Volumetric Sewer Discharge (b) $680,000 As Needed
Total Preliminary Cost Estimate $891,000 to $1,100,000 $4,100,000 to
Notes:
a. Cost estimates based on 2019 dollars with an accuracy range of -30% to +50%. Cost factors and assumptions are described in Section 5.4.
b. The District charges $6.50 per 1,000 gallons discharged through the Special Discharge Permit. The estimated initial cost is based on one year of
discharge in order to satisfy initial Policy Memo 97-005 monitoring requirements for the first year of operation.
121
Potential Sources of Grant/Loan Funding
Source Description Eligibility Funding Constraints
Groundwater Quality Funding
– Proposition 1 Groundwater
Grant Program
This program provides funds for planning and implementing groundwater projects that prevent or
clean up contamination of groundwater that serves or has served as a source of drinking water.
Priorities: threat posed by groundwater contamination to drinking water supply, potential for
contaminant to spread, potential to enhance local water supply reliability, recharge vulnerable
high-use basins, projects with no viable responsible parties. Contaminants can be natural or
human-made. Funding is also available for drinking water treatment and septic-to-sewer projects
that benefit Disadvantaged Communities (DACs) or Economically Disadvantaged Areas (EDAs) and
prevent or reduce contamination of municipal or domestic wells.
Public Agencies, Tribes, Public Utilities,
Non-Profits, Mutual Water Companies
Application Deadline: Anticipated future
application (late 2020)
Planning grants range from $100,000 to $2 million. Implementation grants range from $500,000 to
$50 million. DAC/EDA projects can receive up to $5 million for drinking water treatment. There is a
50% cost share, which can be reduced for projects benefitting DACs/EDAs.
Groundwater Treatment &
Remediation (Proposition 68)
Funding for treatment and remediation activities for the reduction or prevention of contamination
of groundwater that serves as a source of drinking water. Projects must address contamination
resulting from a discharge of waste. The project must be identified as a high priority by the
applicable state or federal agencies (e.g., Water Board, DTSC, US EPA, DWR). Project priorities and
preferences are outlined in the guidelines. It is expected that proposals will primarily consist of
requests to fund O&M at existing facilities. New infrastructure projects will generally be directed to
the Proposition 1 Groundwater Grant Program, except for small-scale capital improvements that
will reduce long-term O&M costs.
Public agencies, nonprofit organizations,
public utilities, state and federally
recognized Indian tribes, and mutual
water companies.
Application Deadline: Applications due
January 24, 2020 then rolling application
A total of $74 million is available. Grant amounts range from $500,000 to $5M for O&M activities,
and up to $2M for life cycle cost reduction projects. Cost share requirement is 50% and may be
reduced for DACs or EDAs
Groundwater Quality Funding
– SB 445 Site Cleanup
Subaccount Program (SCAP)
This program provides funds for groundwater projects that remediate harm or threat to human
health, safety, and the environment from surface- or groundwater contamination; regulatory
agency has issued a directive, unless infeasible, responsible party lacks financial resources.
Priorities are: significant threat to human health or the environment, DAC or small community
impact, cost and environmental benefit of project, lack of alternative funding sources.
Contaminants considered are human-made. Projects may include site characterization, source
identification, or implementation of cleanup.
All applicants with eligible projects.
Application Deadline: Continuous
$19.5 million annual appropriation; approximately $18 million available annually for grants and
contracts. No funding request limit.
Drinking Water State
Revolving Fund (DWSRF) –
Planning and Construction
This program provides low interest loans and, in some instances, grants to assist public water
systems in financing projects that (1) address public health risk problems, (2) are needed to comply
with the Safe Drinking Water Act (SDWA), and (3) assist those most in need on a per household
affordability basis. Projects will be assigned a category based on priority and will be placed on the
Comprehensive List in order to be considered for financing. Construction Financing is available for
applicants with complete final plans, specifications, and environmental documentation.
Planning/Design financing is available for applicants who do not have final documentation required
for construction financing. Projects may include the following: treatment systems, distribution
systems, interconnections, consolidations, pipeline extensions, water sources, water meters, water
storages.
Public and community water systems
and non-community water systems
operated by not-for-profit entities.
Application Deadline: Continuous
A total of $260M has been allocated to the program from Proposition 1. Limited grants are
available for DAC projects of up to $5M per project and up to $20M per project with regional
benefits, at least one of which is a small DAC. Cost share based on per household affordability
criteria. Loans are available with interest rates at 1/2 the General Obligation bond rate and 20-
year terms. 2018 interest rate was 1.8%. DACs may be eligible for 0% loans for 30 years, or
complete principal forgiveness for severely disadvantaged communities. (All applications are for
loans; financial review determines if grant funds apply.) Up to $10M in 0% interest financing is
available for a PWS that consolidates with a Severely DAC (SDAC) or extends service to a
DAC/SDAC.
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Cost Share Grant by the El
Dorado County Water Agency
This program provides funds for long- and short-range surveys, regional and purveyor specific
water management plans, development of procedures or techniques, exploratory work, permit
fees, engineering and geological studies, environmental and mitigation feasibility studies, in the
applicant’s service areas or jurisdiction. Historically the Agency has contributed 70% of costs for
water rights related projects (Priority One) and 50% for other eligible projects. Typically, projects
should include at least 50% of matching funds by the applicant.
Application Deadline: Submission
deadline is around April of each Fiscal
Year
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INTERIM REMEDIAL ACTION PLAN
South Y Plume R1 Capture Zone