HomeMy WebLinkAboutProp 1 PCE Plume Characterization Project - Groundwater Grant Program Final Report
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GROUNDWATER GRANT PROGRAM
FINAL REPORT
Grant Recipient: City of San Luis Obispo
Title: Tetrachloroethylene (PCE) Plume Characterization Planning Project
Agreement No.: D1912530
Date: November 30, 2022
Project Type: Planning
Total Project Cost: $2,227,891
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Contents
Executive Summary ............................................................................................................................................ 3
Project Background and Scope of Work Summary ..................................................................................... 3
Project Benefits ........................................................................................................................................... 4
Project Purpose, Goal, and Objectives ....................................................................................................... 4
Background ........................................................................................................................................................ 6
Problem Statement ........................................................................................................................................ 6
Site Location(s) ............................................................................................................................................... 6
Existing Wells .............................................................................................................................................. 8
Project Description ........................................................................................................................................... 10
Project Purpose, Goal, and Objectives ..................................................................................................... 10
Project Scope ................................................................................................................................................ 10
Project Costs ................................................................................................................................................. 12
Project Schedule ........................................................................................................................................... 12
CEQA/Permitting/Project Methodology ...................................................................................................... 12
Public Outreach ................................................................................................................................................ 13
Conclusions ...................................................................................................................................................... 14
References ........................................................................................................................................................ 15
Appendices ....................................................................................................................................................... 17
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Executive Summary
Project Background and Scope of Work Summary
The City of San Luis Obispo Tetrachloroethylene (PCE) Plume Characterization Project (Project) was initiated
to characterize a PCE plume within the San Luis Valley area of the San Luis Obispo Valley Groundwater Basin,
DWR Bulletin 118 Basin No. 3-09 (Basin), in San Luis Obispo County, California. Funding for the planning phase
of the project came from the California State Water Resources Control Board (SWRCB) Proposition 1
Groundwater Grant Program Agreement No. SWRCB0000000000D1912530. Water Systems Consulting, Inc.
(WSC), in coordination with the City of San Luis Obispo (City), has been responsible for the Project planning
and management.
There have been multiple investigations within the San Luis Valley area of the Basin that have focused on
PCE contamination, both at the regional level and the site-specific level. The prior studies delineated a PCE
plume that impacted a considerable portion of the San Luis Valley area of the Basin, including at least one
well the City intends to use for drinking water supply. Migration of the plume appeared to threaten other
potable drinking water supply wells and non-potable wells in the San Luis Valley area of the Basin. The
primary groundwater users in the Basin include municipal, agricultural, and domestic (i.e., rural residential,
small community water systems, and small commercial entities) users.
The project included the following work:
Preparation of a Remedial Investigation/ Feasibility Study Work Plan which summarizes historical
data and background studies required to understand the current PCE plume extents and data gaps.
The Work Plan included preparation of the required field investigations to characterize the plume.
Performed field investigations to support plume characterization. The field investigations included
well profiling and groundwater and soil sampling. The well profiling included water quality testing of
4 existing active and inactive water supply wells. The groundwater and soil sampling included taking
borings at 30 locations to collect samples to investigate the physical extent of the PCE plume.
Preparation of a Remedial Investigation Report which summarizes the field investigation work
completed to improve the understanding of the plume and show the current characterization of the
plume including the plume extents and concentration distribution.
Creation of a groundwater model to perform a hydraulic capture zone analysis to evaluate PCE
capture with a range of treatment well alternatives.
Preparation of a Feasibility Study Report to evaluate treatment well alternatives and technologies to
treat the PCE Plume and meet the remedial action objectives.
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Project Benefits
The Project is critical for the City to secure existing groundwater supplies and will provide the following
benefits:
1. Provides the tools necessary to enhance local water supply reliability for the City which otherwise
relies on surface water supplies to meet demands
2. Recommends cleanup alternatives (e.g., treatment) necessary to successfully improve the
sustainability of the Basin, a High Priority Basin, which has limited groundwater as a source for
drinking water
3. Benefits the City, a disadvantaged community, by improving its water supply resiliency and availability
Project Purpose, Goal, and Objectives
Long-term exposures in drinking water above the Federal and California maximum contaminant levels (MCL 1)
of 5 micrograms per liter (μg/L) can cause adverse effects to the liver, kidneys, and central nervous system
(SWRCB, 2017). The primary purpose of the City’s PCE Plume Characterization Project (Project) is to conduct
a remedial investigation and feasibility study to characterize the PCE plume and evaluate and develop
alternatives for the clean-up (e.g. extraction and treatment), and future removal of PCE contamination in
drinking water wells in the San Luis Valley area of the Basin. The Project’s intent is to characterize the PCE
plume by delineating the PCE plume’s physical extents by measuring the concentration of PCE in groundwater
throughout the project area.
Based on this purpose, the goal of the project is to expand and diversify the City’s water supply portfolio to
improve water supply resiliency. Specific objectives include:
1. Characterize and delineate the PCE plume through subsurface investigations, and provide ongoing
monitoring of the plume by installation of a groundwater monitoring well network. Installation of the
monitoring well network is proposed for a possible future implementation phase of the project.
2. Estimate plume migration and degradation over time. Additional fate and transport modeling is
recommended to better predict the PCE plume migration and degradation over time.
3. Identify influent water quality for well head treatment at existing non-operable production wells.
1 MCLs are drinking water standards adopted as regulations by the State of California to protect public health.
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Recommendations and Next Steps
The feasibility study recommends equipping up to two groundwater treatment wells which use granular
activated carbon wellhead treatment systems to remove PCE from pumped groundwater prior to using the
water in the City’s drinking water system.
The next steps in this Project, which has applied for Prop 1 Round 3 funding, will be creating a fate and
transport groundwater model to verify the initial treatment recommendations followed by implementation
of the recommended pump and treat systems to remove PCE from the plume affecting the San Luis Valley
area of the Basin.
Grant Agreement Description Actually Completed
Remedial Investigation Work Plan Completed as RI/FS Work Plan
Remedial Investigation Work Plan Addendum Completed as Work Plan Addendum Technical
Memorandum
Feasibility Study Work Plan Completed as RI/FS Work Plan
Proposed Changes from the Remedial Investigation
Work Plan
Completed as Work Plan Addendum Technical
Memorandum
Conduct soil and remedial groundwater
investigation at a minimum of 25 locations and
obtain a minimum of 25 groundwater samples,
conduct vertical flow and chemistry profiling at a
minimum of 4 wells, perform aquifer testing at a
minimum of 1 well, in accordance with approved
Remedial Investigation Workplan
Drilled 34 borings, collected 98 groundwater
samples and 10 soil samples, conducted vertical
flow and chemistry well profiling at 4 existing
wells, conducted aquifer testing at 1 existing well.
Evaluation Summary to Site Monitoring Wells Monitoring Well siting deferred to future phase
Well Completion Report Monitoring Well siting deferred to future phase
Remedial Investigation Report Completed
Groundwater Fate and Transport Modeling Completed as Groundwater Flow Modeling
Groundwater Fate and Transport Modeling Report Completed as Hydraulic Capture Zone Analysis
Feasibility Study Report Completed
Outreach Materials and Web Links Completed
Workshop Materials, Sign-in Sheet, and Photo
Documentation
Completed
Table 1. Comparison Table of Proposed Scope of Work Versus Actual Project Completed.
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Background
Problem Statement
Tetrachloroethylene (PCE) is a chemical used in cleaning, textile operations, and metal degreasing activities.
The San Luis Valley portion of the San Luis Obispo Valley Groundwater Basin (Basin) is a source of drinking
water impacted by regional PCE contamination. Long-term exposures in drinking water above the Federal
and California maximum contaminant levels (MCL) of 5 micrograms per liter (μg/L) can cause adverse
effects to the liver, kidneys, and central nervous system (SWRCB, 2017). The contamination of the Basin by
PCE limits the City of San Luis Obispo’s (City) use of groundwater as a source of drinking water.
Site Location(s)
The Basin is oriented in a northwest-southeast direction and is composed of unconsolidated or loosely
consolidated sedimentary deposits. It is approximately 14 miles long and 1.5 miles wide. It covers a surface
area of about 12,700 acres (19.9 square miles). The Basin is bounded on the northeast by relatively
impermeable bedrock formations of the Santa Lucia Range, and on the southwest by the formations of the
San Luis Range and the Edna fault system. The bottom of the Basin is defined by the contact of permeable
sediments with the Miocene-aged impermeable bedrock and Franciscan Assemblage rocks (DWR, 2003).
The project area, shown in Figure 1, is located in the San Luis Valley, south of California Polytechnic State
University in the southern portion of the City of San Luis Obispo, in San Luis Obispo County, California and
within DWR Bulletin 118 Basin No. 3-09 and Region 3 of the SWRCB. The PCE plume lies between Los Osos
Valley Road and S. Higuera Street, following alongside Highway 101 and San Luis Obispo Creek. The
suspected source or sources of the PCE plume appear to be located south of Marsh Street and north of
South Street, east of Highway 101. The source of the PCE has been attributed to several dry cleaners and
power generation facilities that once existed in this area. These sites are currently undergoing or have
undergone remedial clean-up efforts. Figure 1 shows, in blue, the plume location as previously assumed
based on the 2005 QPS plume delineation report and the current plume limits, in green, as delineated by
the remedial investigation work performed as part of this Grant Agreement.
Previous studies estimating the extent of the PCE plume completed by QORE Property Science (QPS) and
the Regional Water Quality Control Board (RWQCB) show that the plume has dispersed over time and
passed through the narrow passageway between west and east South Hills, where San Luis Creek flows
north to south, indicated as the 2005 QPS Plume Delineation on Figure 1. The 2022 results, shown as the
2022 Plume Delineation on Figure 1, indicate the PCE plume does not stretch as far south as the QPS Plume
estimated and the northern tip of the plume lies further to the southeast.
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Figure 1. Project Area.
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Existing Wells
Many San Luis Obispo public wells within the San Luis Valley have been evaluated for PCE impacts since the
early 1990’s. Key existing wells are shown below in Table 2 and on Figure 2. Most of the wells discussed in
the sections above are screened in the alluvial aquifer while the public wells or irrigation wells listed in Table
3-2 below are screened in both the alluvial aquifer and Paso Robles Aquifer which is the primary drinking
water aquifer for the San Luis Obispo region.
Existing Wells
Well Name
Well Depth
(feet bgs)
Screen Interval
(feet bgs)
Approximate
Elevation
(amsl)
Border Patrol Well 61 Not Available 119
Pacific Beach #1 Well 130 40 - 130 130
Corp Yard Well 70 50 - 70 128
Mitchell Park Well 48 28 - 48 216
Fire Station #4 Well 125 55 - 125 140
Jack House Well 52 32 - 52 187
SLO WWTP Monitoring Well 3 18 Not Available 131
Highway 101 Well 135 45 - 80; 110 - 135 120
San Luis Ranch Well 1 120 Not Available 121
San Luis Ranch Well 2 60 Not Available 135
San Luis Ranch Well 5 80 Not Available 129
IOOF Cemetery Well Not Available Not Available 152
Pesquini Well Not Available Not Available 147
Meisnner Well Not Available Not Available 135
Kennedy Fitness Well Not Available Not Available 130
Avila Ranch Well Not Available Not Available 113
Lockheed Martin Well Not Available Not Available 112
Kaiser Sand and Gravel Well Not Available Not Available 118
Toyota Well 175 60 - 120; 140 - 175 114
Notes:
SLO San Luis Obispo
bgs below ground surface
amsl above mean sea level
Table 2. Key Existing Wells
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Figure 2. Key Wells in the Project Vicinity
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Project Description
Project Purpose, Goal, and Objectives
The primary purpose of the City’s PCE Plume Characterization Project (Project) is to conduct a remedial
investigation and feasibility study to characterize the PCE plume and evaluate and develop alternatives for
the clean-up (e.g., treatment) and prevention of PCE contamination in drinking water wells in the San Luis
Valley area of the Basin. Long-term exposures in drinking water above the Federal and California maximum
contaminant levels (MCL2) of 5 micrograms per liter (μg/L) can cause adverse effects to the liver, kidneys,
and central nervous system (SWRCB, 2017). The Project’s intent is to characterize the PCE plume by
delineating the PCE plume’s physical extents by measuring the concentration of PCE in groundwater
throughout the project area.
Based on this purpose, the goal of the project is to expand and diversify the City’s water supply portfolio to
improve water supply resiliency. Specific objectives include:
1. Characterize and delineate the PCE plume through subsurface investigations, and provide ongoing
monitoring of the plume by installation of a groundwater monitoring well network. Installation of the
monitoring well network is proposed for a possible future implementation phase of the project.
2. Estimate plume migration and degradation over time – See the Remedial Investigation Report (WSC,
2022) for information on the plume characterization. Additional fate and transport modeling is
recommended to better predict the PCE plume migration and degradation over time.
3. Identify influent water quality for well head treatment at existing non-operable production wells.
Project Scope
The major Project scope milestones and activities are listed below:
Prepare a Remedial Investigation/ Feasibility Study Work Plan, finalized in 2021. The Remedial
Investigation/ Feasibility Study Work Plan summarizes historical data and background studies to
understand the current PCE plume extents and data gaps. The report includes the proposed
investigation work plan to further understand the full extent of the PCE plume. It also establishes
the remedial action objective and identifies treatment alternatives to evaluate the feasibility of
developing treatment wells.
2021-2022 Field Investigations
2 MCLs are drinking water standards adopted as regulations by the State of California to protect public health.
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o Well Profiling: Performed well profiling and water quality testing of 4 existing active and
inactive water supply wells. The tested wells were the CJAR Ag Well, Highway 101 Well, San
Luis Ranch Well, and Pacific Beach Well. Generally, well profiling involved pumping and
testing the wells to determine where in the aquifer, vertically, the water is preferentially
entering the well casing and to determine if the tested wells were interacting with each
other. Water quality testing was performed for volatile organic compounds (VOCs) including
PCE and per- and polyfluoroalkyl substances (PFAs). Well Profiling work was completed in
September 2021.
o Borings for Groundwater and Soil Sampling: The borings for groundwater and soil sampling
work portion of the field investigations consisted of drilling and collecting soil and
groundwater samples from 30 locations throughout the previously known PCE plume
delineation area to investigate the current physical extent of the PCE plume. Borings work
was performed from March to July 2022.
Prepare a Remedial Investigation Report, draft completed in October 2022. The Remedial
Investigation Report summarizes the field investigation work completed to improve the
understanding of the plume.
Prepare a Groundwater Modeling Report. The data from the 2021-2022 field investigation was used
to update and recalibrate the existing groundwater flow model. Once updated, the model was used
to perform a hydraulic capture zone analysis to evaluate PCE capture with a range of treatment well
alternatives. The hydraulic capture zone analysis was used to understand the ability of the
treatment alternatives to meet the remedial action objectives.
Prepare a Feasibility Study Report to evaluate treatment well alternatives and technologies to treat
the PCE Plume and meet the remedial action objective. The Feasibility Study Report builds upon
information presented in the previous reports and the draft was completed in October 2022.
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Project Costs
A summary of budget costs in alignment with Amendment 2 to the Grant Agreement (executed
06/14/2022) is provided in Table 3.
Proposition 1 GROUNDWATER GRANT PROGRAM -
BUDGET SUMMARY
Budget Category Grant Funds Local Match
Funds Total % Local
Match
1. Project Administration $,78,954 $72,883 $151,837 48%
2. Planning/Design/Engineering/
Environmental $157,126 $0 $157,126 0%
3. Construction/Implementation $1,736,326 $138,161 $1,874,486 7%
4. Monitoring/Performance $133 $0 $133 0%
5. Education/Outreach $23,959 $20,350 $44,309 46%
Grand Total: $1,996,498 $231,394 $2,227,891 10.4%
*Budget Table is accurate as of 12/30/2022.
Table 3. Budget Summary
Project Schedule
The Grant Agreement was executed by the State Water Board on June 16, 2020, and subsequently
amended on December 4, 2020 and February 11, 2022 to revise the Work Completion Date, the Final
Reimbursement Request Date, the Records Retention End Date, the body of the agreement and Exhibits A
(Submittal Schedule), B (Budget), C (General and Programmatic Terms and Conditions), and D (Special
Conditions). Revisions to the Project Schedule are captured in Exhibit B of the Grant Agreement and
provided as a table and a Gantt Chart in Appendix A below.
CEQA/Permitting/Project Methodology
The City determined the project was exempt from CEQA per Section 15262: Feasibility and Planning
Studies. An NOE was prepared by the City and signed on February 27, 2019 and cited, “This is the Study
Phase only of the PCE Plume Characterization project. If the project proceeds to an implementation phase,
it would require additional CEQA analysis.”
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Permits required and obtained for the project are listed in the Table 4.
Permit Description
Caltrans Encroachment Permit
for boring work
Caltrans Encroachment Permit 0522 6DP 0544 for work
on B-11, B-17, and B-12 in Caltrans ROW
Caltrans Encroachment Permit
for boring work
Caltrans Encroachment Permit 0522 NSV 0140 for work
on B-11, B-17, and B-12 in Caltrans ROW
City of SLO Encroachment
Permit for boring work
City of SLO Encroachment Permit ENCR-0406-2022 for
work on B-01 to B-16, B-18 to B-25, B-29, and B-31 to B-
34 for work in City Street ROW
County of SLO well drilling
permits for boring work
County of SLO EHS MW Permit 2022-015 to 2022-028
for work on B-01 to B-16, B-18 to B-25, B-29, and B-31 to
B-34
County of SLO well drilling
permits for boring work
County of SLO EHS MW Permit 2022-061 for work on B-
11R
County of SLO well drilling
permits for boring work
County of SLO EHS MW Permit 2022-062 for work on B-
18R
Table 4. Project Permits
Public Outreach
A public meeting to discuss the Project with the Community was held on Wednesday, November 16, 2022.
Outreach included:
Invitations for utility customers in the affected area, members of the Technical Advisory Committee,
and other stakeholders in the community using EventBrite and the City’s electronic distribution system;
Website Content created for https://www.slocity.org/government/department-directory/utilities-
department/water/water-sources/groundwater and a QR code generated for easier access to
content about the PCE Plume Characterization Study, FAQs, and meeting;
Ads placed in local papers SLO Tribune and New Times;
Social Media posts on the City’s channels;
Electronic Boards at various locations throughout the City;
Press release for local media outlets;
Workshop Poster for display at locations throughout City;
Handout for public meeting participants;
Frequently Asked Questions handout for participants;
Poster Boards and Presentation.
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Conclusions
The project objectives were successfully completed, and are listed below for reference:
1. Characterize and delineate the PCE plume through subsurface investigations, and provide ongoing
monitoring of the plume by installation of a groundwater monitoring well network. Installation of the
monitoring well network is proposed for a possible future implementation phase of the project.
a. The plume was delineated and a concentration contour map was prepared using the field
investigation data, see Figure 3.
2. Estimate plume migration and degradation over time.
a. Capture of the plume was shown to be feasible using the Groundwater Flow Model. Additional
fate and transport modeling is recommended to better predict the PCE plume migration and
degradation over time.
3. Identify influent water quality for well head treatment at existing non-operable production wells.
a. The feasibility study recommends equipping up to two groundwater treatment wells which
use granular activated carbon wellhead treatment systems to remove PCE from pumped
groundwater prior to using the water in the City’s drinking water system.
The next steps in this Project, which has applied for Prop 1 Round 3 funding, will be creating a fate and
transport groundwater model to verify the initial treatment recommendations followed by implementation
of the recommended pump and treat systems to remove PCE from the plume affecting the San Luis Valley
area of the Basin.
There were several important lessons learned on the project.
Needed to account for RWQCB sampling requirements, which added sonic boring, removed soil
vapor, and required revision of the WP which slowed down exploratory boring and increased the
project budget.
Caltrans encroachment permits became a critical path item, and Caltrans’ jurisdiction extended
further than originally anticipated, need to coordinate with Caltrans earlier.
Analytical laboratories are operating at capacity right now which extended time required to obtain
results, need to build in allowance for laboratory delays.
Exploratory borings required night work in many locations in the City because of traffic closure
limitations which increased staffing needs for observation. In the future, need to be aware of
special working hour limitations.
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The project required an extension of the original schedule due to delays caused by the COVID 19 pandemic.
The project was completed within the awarded grant amount, although the scope of the project required
reduction to account for increases in cost associated with the COVID 19 pandemic, inflation, and the need
for deeper groundwater data gathering than initially assumed.
References
DWR. (2003). California's Groundwater: Bulletin 118 - Update 2003, Groundwater Basin 28 Descriptions.
SWRCB. (2017). Groudnwater Information Sheet - Tetrachloroethylene (PCE). State Water Resources Control
Board, Division of Water Quality, GAMA Program.
WSC. (2021). RI/FS Work Plan .
WSC. (2022). Draft Remedial Investigation Report for the City of San Luis Obispo PCE Plume Characterization
Project.
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Figure 3. PCE Concentration Contours
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Appendices
Appendix A - List of Deliverables
ITEM DESCRIPTION OF SUBMITTAL DUE DATE %
COMPLETE
DATE
SUBMITTED
1. Project Management
1.2 Notification of Upcoming Meetings, Workshops, and
Trainings
15 Working Days
Prior 100% Ongoing
1.3 Detailed Project Schedule 60 Days After
Execution 100% February 2, 2022
1.4 Periodic and Final Site Visits As Needed 100% July 1, 2022
1.5 Pre-, During, and Post-Implementation Photos Ongoing 100% October 30, 2022
2. General Compliance Requirements/Project Effectiveness and Performance
2.1 Global Positioning System (GPS) Information Ongoing 100% May 4, 2021
2.2 Monitoring and Reporting Plan (MRP) November 2020 100% October 21, 2020
2.3 Quality Assurance Project Plan (QAPP) November 2020 100% October 21,
2020
3. Environmental Compliance and Permitting
3.1.1 Draft CEQA Document (if applicable) N/A N/A
3.1.2 Final CEQA Document Complete 100% March 10, 2020
3.2 List of Approvals, Entitlements or Permits April 2022 100% June 17, 2022
4. Technical Advisory Committee (TAC)
4.1 List of TAC Members, with Roles, Responsibilities, and
Affiliations November 2020 100% October 21, 2020
4.2 Summary of the Kickoff Meeting November 2020 100% October 21, 2020
4.3 Agendas, Meeting Minutes, and Sign-In Sheets Ongoing 90%
5. Remedial Investigation/Feasibility Study Workplans
5.1 Remedial Investigation Workplan October 31, 2020 100% October 21, 2020
5.1.11 Remedial Investigation/Feasibility Study Workplan
Addendum May 2022 100% June 8, 2022
5.2 Feasibility Study Workplan October 31, 2020 100% October 21,
2020
6. Remedial Investigation and Reporting
6.1.1 Proposed Changes from the Remedial Investigation
Workplan August 2022 100% February 2, 2022
6.1.4 Evaluation Process Summary April 2022 100% June 8, 2022
6.1.5 Well Completion Report N/A N/A
6.2 Remedial Investigation Report September 30,
2022 100% December 30,
2022
7. Groundwater Flow Modeling
7.2 Groundwater Flow Modeling Report October 20, 2022 100% December 30,
2022
8. Feasibility Study and Reporting
8.2 Feasibility Study Report October 31, 2022 100% December 30,
2022
9. Public Outreach
9.1 Outreach Materials and Web Links Ongoing 95%
9.2 Workshop Materials, Sign-in sheet, and Photo
Documentation October 31, 2022 100% December 15,
2022
A2.2 REPORTS
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ITEM DESCRIPTION OF SUBMITTAL DUE DATE %
COMPLETE
DATE
SUBMITTED
A.2.2.1 Progress Reports Quarterly 90
11/13/2020
2/19/2021
4/27/2021
8/11/2021
10/19/2021
2/2/2022
6/29/2022
8/8/2022
11/9/2022
A.2.2.2
(a)(1) Draft Final Project Report October 31, 2022 100% October 31, 2022
A.2.2.2
(a)(2) Final Project Report November 30,
2022 100% November 30,
2022
A.2.2.2
(a)(3) Final Project Summary Before Work
Completion Date --
A.2.2.3 As Needed Reports As needed Ongoing
B.1.7
(b)(6) Final Reimbursement Request January 31, 2023 0%
B.1.7 (d) Reimbursement Requests Quarterly 90%
11/13/2020
2/19/2021
4/27/2021
8/11/2021
10/19/2021
2/2/2022
6/29/2022
8/8/2022
11/9/2022
NOTE: Due dates reflect SWRCB D1912530 Amendment 2, executed on 2/11/2022 modified by Submittal Schedule Update Form submitted
9/8/2022.
19 DRAFT
20 DRAFT
21 DRAFT
Appendix B - Photographs
Boring Location B-5 CPT rig in the background,
soils core rig in the foreground
Interior of CPT rig showing typical groundwater
sampling
Soil collected from soil coring Typical CPT log used to determine lithology and
select locations for groundwater samples
22 DRAFT
CPT rig at B-15 Sonic drilling rig at B-31
Soil coring at B-33 Hand auger at B-22 to clear utilities prior to drilling