HomeMy WebLinkAboutCT 2019-0003; CARLSBAD STATION; PRELIMINARY INFILTRATION FEASIBILITY STUDY FOR CARLSBAD STATION; 2019-05-13 ADVANCED GEOTECHNICAL SOLUTIONS, INC.
485 Corporate Drive, Suite B
Escondido, California 92029
Telephone: (619) 867-0487 Fax: (714) 409-3287
ORANGE AND L.A. COUNTIES INLAND EMPIRE SAN DIEGO AND IMPERIAL COUNTIES
(714) 786-5661 (619) 867-0487 (619) 867-0487
Carlsbad Village 80, LLC May 31, 2019
McKellar McGowan P/W 1809-04
HF CV80LLC Report No. 1809-04-B-5
888 Prospect St. 330
La Jolla, CA 92037
Attention: Mr. Chris McKellar
Subject: Preliminary Infiltration Feasibility Study for Carlsbad Station, Roosevelt Street and
State Street, Carlsbad, California
References: See Attached
Gentlepersons:
In accordance with your request, Advanced Geotechnical Solutions, Inc. (AGS) has prepared this
infiltration feasibility study for the proposed Carlsbad Station residential development in Carlsbad,
California. This report is intended to meet the preliminary infiltration testing requirements of the County
of San Diego. The report incorporates the Existing Conditions/Demo plan (print dated April 8, 2019)
prepared by bHA, Inc. for the subject project. AGS has evaluated the feasibility for storm water infiltration
in accordance with the 2016 City of Carlsbad BMP Design Manual. Worksheet Form I-8 and associated
supporting data are presented in Appendix A.
1.0 SITE DESCRIPTION AND PROPOSED DEVELOPMENT
The “L” shaped 1.7-acre site (see Figure 1) is bounded by Roosevelt Street to the northeast and State Street
to the southwest and by commercial and residential developments to the northwest and southeast. Currently
the site supports several one- to two-story commercial buildings constructed in the 1950’s to 1980’s (?)
along with several driveways and at-grade parking. Based upon our review of the existing condition plan,
elevations at the site range from a high of 46 feet MSL at the southeast corner, to a low of 40 feet above
mean sea level (msl) at the northwest corner.
Detailed development plans were not available for our review. It is our understanding that the existing
commercial and residential structures will be demolished and replaced with a 3- to 4-story high residential
structure with one level of underground parking consisting of a concrete podium level with a “slab-on-
grade” foundation system. The upper floors will consist of a wood frame/steel stud structure. Grading is
anticipated to include one (1) to two (2) feet of cut and fill along the building perimeter with deeper cuts
to fifteen (15) feet at the bottom of the subterranean garage portion of the structure.
2.0 FIELD INVESTIGATION
On May 23, 2019, three (3) percolation test boreholes (P-1 through P-3) were manually excavated at the
project site to depths ranging between 3 and 5 feet below ground surface (bgs). The percolation tests were
performed to evaluate the feasibility of storm water infiltration at the site and provide preliminary design
infiltration rates in general conformance with Appendix D, Section D.2 of the BMP Design Manual.
FIGURE
1
DATE:
5/19
SITE LOCATION MAP
PROJECT NO.:
1809-04
NOTE: ALL DIMENSIONS, DIRECTIONS AND LOCATIONS ARE APPROXIMATE.SOURCE: USGS, SAN LUIS REY QUADRANGLE, 2018.
CARLSBAD STATION
STATE STREET AND ROOSEVELT STREET
CARLSBAD, CALIFORNIA
N
BuenaVista Lagoon
SITE
SCALE 1”= 1,000’
May 31, 2019 Page 2
P/W 1903-05 Report No. 1903-05-B-5
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
Previously, three exploratory borings (B-1 through B-3) had been advanced on March 18, 2019 to a
maximum depth of 35 feet bgs using a truck-mounted drill rig. Approximate exploratory boring and
percolation test locations are shown on Figure 2, Exploration Location Map. Engineers from our firm
logged the borings for soil and geologic conditions. The boring logs are presented in Appendix B.
3.0 GEOLOGY
Percolation test boring P-1 extended to artificial fill materials and borings P-2 and P-3 extended to
Quaternary Old Paralic Deposits, Units 6 and 7 (Map symbol Qop6-7). The artificial fill consisted of fine- to
medium-grained sand with silt. The old paralic deposits generally consist of silty to clayey fine-grained
sand. The site is underlain by Santiago Formation silty sand at 20 feet bgs. Groundwater was encountered
at approximate depths of 9 to 13 feet bgs corresponding to approximate elevation 32 feet msl.
4.0 TEST PROCEDURE
The test holes were cleaned of loose debris then successively filled with more than 5 gallons of clean,
potable water and allowed to pre-soak. The same day the test holes were cleaned of sediment and the bottom
was lined with approximately 2 inches of washed gravel prior to infiltration testing.
A series of falling head infiltration tests were performed. The test holes were filled with clean, potable water
to approximately 23 to 26 inches above the infiltration surface and allowed to infiltrate. The water level
was allowed to drop for a 30-minute period and then measured to calculate the drop rate in inches per hour.
The test hole was then refilled with water as necessary and the test procedure was repeated over the course
of several hours until a stabilized percolation rate was recorded. The stabilized percolation rate was then
converted to an infiltration rate based on the “Porchet Method” utilizing the following equation:
Logs of the field testing and graphical representations of the test data presented as infiltration versus time
interval are included in Appendix AA as supporting documents for Form C.4-1.
DATE:5/19PROJECT NO.:1809-04NOTE: ALL DIMENSIONS, DIRECTIONS AND LOCATIONS ARE APPROXIMATE.FIGURE :3CARLSBAD STATIONSTATE STREET AND ROOSEVELT STREET CARLSBAD, CALIFORNIAEXPLORATION LOCATION MAPSOURCE: bHA, Inc. 2019, EXISTING CONDITIONS/DEMO PLAN.LEGENDAPPROXIMATE BORING LOCATION TD = TERMINATION DEPTH IN FEET P-1TD=3' B-3TD=31'APPROXIMATE INFILTRATION TEST LOCATION TD = TERMINATION DEPTH IN FEET P-3TD=5'ROOSEVELT STREETP-2TD=4'P-3TD=5'B-1TD=35' B-2TD=31' B-3TD=31' SCALE 1”= 40’
May 31, 2019 Page 3
P/W 1903-05 Report No. 1903-05-B-5
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
5.0 TEST RESULTS AND PRELIMINARY DESIGN VALUES
The results of our testing are summarized in Table 1 below.
TABLE 1
SUMMARY OF INFILTRATION TEST RESULTS
Test Hole
No.
Depth of
Test Hole
Approximate Test
Elevation
Geologic
Unit Description (USCS) Tested Infiltration
Rate (in./hr.)
P-1 3.1 feet 40.9 ft msl Fill Well-graded Sand with Silt (SW) 0.905
P-2 4.1 feet 38.9 ft msl Qop6-7 Silty to Clayey Sand (SC-SM) 0.454
P-3 4.9 feet 36.1 ft msl Qop6-7 Silty to Clayey Sand (SC-SM) 0.302
In accordance with Appendix D, Section D.5. of the BMP Design Manual, a ‘Factor of Safety’ should be
applied to the tested infiltration rates to determine the design infiltration rates. The factor of safety is
determined by Worksheet D.5-1 and possesses a numerical value between 2 and 9.
For the proposed project site, the factor of safety worksheet yielded a Combined Factor of Safety (Stotal) of
4.0. However, for feasibility screening it is recommended that a Factor of Safety of 2.0 be utilized. Table 2
below summarizes the preliminary design infiltration rates for the subject test holes utilizing a factor of
safety of 2.0.
TABLE 2
PRELIMINARY DESIGN INFILTRATION RATES
Test Hole
No.
Tested Infiltration Rate
(in. /hr.)
Factor of
Safety
Design Infiltration Rate
(in. /hr.)
P-1 0.905 2.0 0.45
P-2 0.454 2.0 0.23
P-3 0.302 2.0 0.15
6.0 DESIGN CONSIDERATIONS
6.1. Groundwater
Groundwater was encountered at approximate depths ranging between 9 feet and 13 feet bgs.
According to the BMP Design Manual, in areas where infiltration BMPs are planned, a minimum
separation of 10 feet between the infiltration surface and groundwater should be maintained.
6.2. Soil Characteristics and Anticipated Flow Paths
Based on our subsurface exploration and infiltration testing performed at the site, the Old Paralic
Deposits will allow for vertical infiltration with preliminary design infiltration rates on the order
0.15 to 0.45 inches per hour with an average infiltration rate of 0.28 inches/hour.
Storm water is anticipated to have low to moderate vertical flow to the underlying Santiago
Formation at which point variable lateral flow is anticipated along the contact of dissimilar
permeability.
May 31, 2019 Page 4
P/W 1903-05 Report No. 1903-05-B-5
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
6.3. Geotechnical Hazards
Groundwater was encountered at approximate depths of 9 to 13 feet bgs. Due to the estimated depth
of the proposed basins, we anticipate that the minimum separation of 10 feet between the infiltration
surface and groundwater recommended in the BMP Design Manual will not be maintained. The
minimum separation from groundwater can be reduced provided adequate pre-treatment measures
to maintain water quality are incorporated into the BMP design.
It is our understanding that the proposed basins will be located in close proximity to existing or
proposed structures and underground utilities. There is a high likelihood for water intrusion to occur
in subjacent utility trenches and saturated soil conditions beneath structures and other settlement
sensitive improvements.
The potential geotechnical hazards should be mitigated by designing the basin for no infiltration
and lining the basin with an impermeable membrane, deepening foundation elements of nearby
proposed structures, installing moisture cut-off walls between the infiltration basins and nearby
settlement-sensitive improvements, and/or backfilling subjacent utility trenches with a lean sand-
cement slurry.
6.4. Soil Contamination
During our recent site investigation, no evidence of soil contamination was observed, nor is any
contamination known to exist onsite. Utilizing the DWR online resource Geotracker.ca.gov, no
open cases were identified within 1000 feet of the subject site.
6.5. Proximity to Water Supply Wells
No known water supply wells are located within a 100-foot radius of the site.
6.6. Maintenance of Infiltration Device
Regular maintenance of any infiltration system is critical to the long term successful operation of
the system. Responsibilities of maintaining the system are typically borne by the owner.
Improperly maintained infiltration devices and basins have a high failure rate. A plan should be
developed by the designer of the system and implemented throughout the project’s lifetime.
7.0 CONCLUSIONS AND RECOMMENDATIONS
Preliminary infiltration testing in the upper soils yielded preliminary design infiltration rates ranging
between 0.15 to 0.45 inches per hour which indicates partial infiltration. However, infiltration at the
potential BMP locations will increase the potential for geotechnical issues such as water intrusion and
ground settlement. Preventing all water intrusion is not considered feasible unless infiltration is blocked by
installing an impermeable liner on all underground BMP improvements. According to our review of
preliminary biofiltration section details, the proposed BMPs will have an impermeable liner and the outflow
will be directed to the storm drain system.
Other mitigation measures typically include an appropriate setback between nearby improvements and
infiltration devices and construction of a cutoff wall, such as placement of a vertical impermeable liner or
slurry filled trench, to reduce infiltration of water below adjacent improvements. To prevent the migration
of water along utility pipe bedding zones, slurry backfill should be considered in utility pipes located near
May 31, 2019 Page 5
P/W 1903-05 Report No. 1903-05-B-5
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
infiltration devices. Due to the geotechnical hazards discussed above, infiltration is not recommended
within the proposed BMPs. The current design indicates that the BMP’s will be lined and no infiltration is
anticipated.
The infiltration rates presented in this report are based on limited testing performed as part of a preliminary
screening for feasibility purposes. Dependent upon the final location, depth, and type of proposed BMP,
additional testing may be warranted.
Advanced Geotechnical Solutions, Inc. appreciates the opportunity to provide you with geotechnical
consulting services and professional opinions. If you have any questions, please contact the undersigned at
(619) 867-0487.
Respectfully Submitted,
Advanced Geotechnical Solutions, Inc.
_________________________________ ____________________________________
ANDRES BERNAL, Sr. Geotechnical Engineer PAUL J. DERISI, Vice President
RCE 62366/RGE 2715 CEG 2536, Reg. Exp. 5-31-21
Distribution: (1) Addressee
Attachments: References
Figure 1 - Site Location Map
Figure 2 - Exploration Location Map
Appendix A - Storm Water Standards BMP Design Manual - Form I-8, Support Documents and Field Data
Appendix B - Boring Logs
May 31, 2019 Page 6
P/W 1903-05 Report No. 1903-05-B-5
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
REFERENCES
Advanced Geotechnical Solutions Inc., 2019, “Preliminary Geotechnical Feasibility Investigation, Carlsbad
Station, Carlsbad, California”, dated April 25, 2019, Report No. 1809-04-B-4R.
American Society for Testing and Materials (2008), Annual Book of ASTM Standards, Section 4,
Construction, Volume 04.08, Soil and Rock (I), ASTM International, West Conshohocken,
Pennsylvania.
California Building Standards Commission, 2016, California Building Code, Title 24, Part 2, Volumes 1
and 2.
Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas: California Geological Survey,
California Geologic Data Map No. 6, Scale 1:750,000.
Kennedy, M.P., Tan, S.S., Bovard, K.R., Alvarez, R.M., Watson, M.J., And Gutierrez, C.I., 2007, Geologic
Map of the Oceanside 30x60 quadrangle, California: California Geological Survey, Regional
Geologic Map No. 2, scale 1:100,000
bHA, Inc., 2019, Existing Conditions/Demo Plan, Carlsbad Station, print dated April 8, 2019.
City of Carlsbad, 2016, Storm Water Standard – BMP Design Manual, February 2016 Edition.
State of California Water Boards, May 16, 2019, http://geotracker.waterboards.ca.gov/
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
APPENDIX A
STORM WATER STANDARDS BMP DESIGN MANUAL - FORM I-8
SUPPORT DOCUMENTS AND FIELD DATA
Categorization of Infiltration Feasibility Condition
FORM I-8 (DMA 1)
Part 1 - Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any undesirable
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed facility locations
greater than 0.5 inches per hour? The response to this Screening Question
shall be based on a comprehensive evaluation of the factors presented in
Appendix C.2 and Appendix D.
Provide basis:
Three (3) borehole percolation tests were performed to assess general site feasibility for the implementation of
infiltration type BMP’s. Testing was performed in general conformance with Appendix D, Section D.2 of the current
BMP Design Manual. The stabilized percolation rates were converted to an infiltration rate based on the “Porchet
Method.” For the purpose of feasibility screening, a factor of safety of 2 has been applied to the infiltration rate.
Based on the results of our infiltration testing, the onsite soils possess preliminary design infiltration rates ranging
between 0.15 to 0.45 inches/hour with an average infiltration rate of less than 0.5 inches/hour. A more detailed
discussion of the site-specific infiltration testing can be found in our “Preliminary Infiltration Feasibility Study for
Carlsbad Station, Roosevelt Street and State Street, Carlsbad, California”, dated May 31, 2019, Report No. 1809-
04-B-5.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/data source applicability.
2
Can infiltration greater than 0.5 inches per hour be allowed without increasing
risk of geotechnical hazards (slope stability, groundwater mounding, utilities,
or other factors) that cannot be mitigated to an acceptable level? The response
to this Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.2.
Provide basis:
Design Infiltration rates at the project site are less than 0.5 inches/hour. As such, this screening questions is not
applicable. Further, we anticipate that geotechnical hazards (foundation settlement, groundwater mounding,
utilities, etc.) cannot be mitigated to an acceptable level.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/data source applicability.
Form I-8 Page 2 of 4
Criteria Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed without increasing
risk of groundwater contamination (shallow water table, storm water
pollutants or other factors) that cannot be mitigated to an acceptable level?
The response to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.3.
Provide basis:
Design Infiltration rates at the project site are below 0.5 inches/hour. This screening question is not applicable.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/data source applicability.
4
Can infiltration greater than 0.5 inches per hour be allowed without causing
potential water balance issues such as change of seasonality of ephemeral
streams or increased discharge of contaminated groundwater to surface
waters? The response to this Screening Question shall be based on a
comprehensive evaluation of the factors presented in Appendix C.3.
Provide basis:
We do not anticipate water balance issues or increased discharge of contaminated water to surface waters.
However, per Section C.4.4 of the BMP Design Manual, final determination should be made by the project
design engineer.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/data source applicability.
Part 1
Result*
If all answers to rows 1-4 are “Yes” a full infiltration design is potentially feasible.
The feasibility screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but
would not generally be feasible or desirable to achieve a “full infiltration” design.
Proceed to Part 2
No,
proceed
to Part 2
*To be completed using gathered site information and best professional judgment considering the definition of MEP
in the MS4 Permit. Additional testing and/or studies may be required by the City Engineer to substantiate findings.
Form I-8 Page 3 of 4
Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria
Would infiltration of water in any appreciable amount be physically feasible without any negative
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any appreciable rate
or volume? The response to this Screening Question shall be based on a
comprehensive evaluation of the factors presented in Appendix C.2 and
Appendix D.
Provide basis:
Site specific infiltration testing yielded preliminary design infiltration rates ranging between 0.15 to 0.45
inches/hour with an average infiltration rate of 0.28 inches/hour which corresponds to partial infiltration. A more
detailed discussion of the site-specific infiltration testing can be found in our “Preliminary Infiltration Feasibility
Study for Carlsbad Station, Roosevelt Street and State Street, Carlsbad, California”, dated May 31, 2019, Report
No. 1809-04-B-5.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/data source applicability and why it was not feasible to mitigate low
infiltration rates.
6
Can Infiltration in any appreciable quantity be allowed without increasing
risk of geotechnical hazards (slope stability, groundwater mounding, utilities,
or other factors) that cannot be mitigated to an acceptable level? The
response to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.2.
Provide basis:
The project site is bounded on all sides by existing improvements and is underlain by shallow groundwater (~9
feet below grade). Based on our evaluation, we anticipate that the use of infiltration type BMPs will increase the
risk of geotechnical hazards which cannot be mitigated to an acceptable level. More specifically, infiltration onsite
can lead to water intrusion into adjacent utility trenches, settlement of soils beneath adjacent structures and surface
improvements, and groundwater mounding due to shallow groundwater conditions. From a geotechnical
engineering perspective, infiltration is not recommended.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/data source applicability and why it was not feasible to mitigate low
infiltration rates.
Form I-8 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed without posing
significant risk for groundwater related concerns (shallow water table, storm
water pollutants or other factors)? The response to this Screening Question
shall be based on a comprehensive evaluation of the factors presented in
Appendix C.3.
Provide basis:
It is anticipated that infiltration would pose a significant risk for groundwater due to the shallow water table. If
infiltration is allowed, appropriate pretreatment measures should be incorporated into the design and
construction of site BMPs.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/data source applicability and why it was not feasible to mitigate low
infiltration rates.
8
Can infiltration be allowed without violating downstream water rights? The
response to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.3.
Provide basis:
We do not anticipate infiltration onsite will violate downstream water rights. However, per section C.4.4 of the
BMP Design Manual, the final determination should be made by the project design engineer.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/data source applicability and why it was not feasible to mitigate low
infiltration rates.
Part 2
Result
*
If all answers from row 5-8 are “Yes”, then partial infiltration design is potentially
feasible. The feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is “No”, then infiltration of any volume is considered to
be infeasible within the drainage area. The feasibility screening category is No
Infiltration.
No,
Infiltration
is not
feasible
*To be completed using gathered site information and best professional judgment considering the definition of
MEP in the MS4 Permit. Additional testing and/or studies may be required by the City Engineer to substantiate
findings
PERCOLATION TEST DATA SHEET
Carlsbad Station Project No.: 1809‐04 Date: 5/23/2019
P‐1 Tested By: SS Water Temp.: 58
3 ft. USCS: SW Air Temp.: 60
Test Hole Dimensions (Inches)
Length 37 Width 6.5 Diameter 6.5
Infiltration Test
Trial No. Start Time Stop Time Time Interval Average Perc Rate Infiltration Rate*
(hr and min) (hr and min) (min.) Start Depth End Depth Depth Change Water Column (in./hr.) (in./hr.)
1 11:30 12:00 30 25.75 6.25 19.50 16.00 39.00 3.596
2 12:00 12:30 30 26.00 9.75 16.25 17.88 32.50 2.708
3 12:30 13:00 30 25.25 12.00 13.25 18.63 26.50 2.127
4 13:00 13:30 30 26.00 15.75 10.25 20.88 20.50 1.481
5 13:30 14:00 30 25.75 16.25 9.50 21.00 19.00 1.365
6 14:00 14:30 30 25.75 17.75 8.00 21.75 16.00 1.112
7 14:30 15:00 30 26.00 18.50 7.50 22.25 15.00 1.021
8 15:00 15:30 30 25.75 19.00 6.75 22.38 13.50 0.914
9 15:30 16:00 30 26.00 19.25 6.75 22.63 13.50 0.905
10
11
12
13
14
15
*Calculated via Porchet Method
Test Hole No.:
Depth of Test Hole:
(Pieziometric Surface in inches)
Project:
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0 50 100 150 200 250 300Infiltration Rate, in/hrTime Elapsed (min)
PERCOLATION TEST DATA SHEET
Carlsbad Station Project No.: 1809‐04 Date: 5/23/2019
P‐2 Tested By: SS Water Temp.: 58
4 ft. USCS: SM/SC Air Temp.: 60
Test Hole Dimensions (Inches)
Length 49 Width 6.5 Diameter 6.5
Infiltration Test
Trial No. Start Time Stop Time Time Interval Average Perc Rate Infiltration Rate*
(hr and min) (hr and min) (min.) Start Depth End Depth Depth Change Water Column (in./hr.) (in./hr.)
1 11:40 12:10 30 23.75 14.25 9.50 19.00 19.00 1.497
2 12:10 12:40 30 24.00 16.75 7.25 20.38 14.50 1.071
3 12:40 13:10 30 24.00 16.25 7.75 20.13 15.50 1.158
4 13:10 13:40 30 23.75 18.00 5.75 20.88 11.50 0.831
5 13:40 14:10 30 23.25 18.50 4.75 20.88 9.50 0.686
6 14:10 14:40 30 23.75 19.25 4.50 21.50 9.00 0.632
7 14:40 15:10 30 23.25 20.00 3.25 21.63 6.50 0.454
8 15:10 15:40 30 23.25 20.00 3.25 21.63 6.50 0.454
9
10
11
12
13
14
15
*Calculated via Porchet Method
Project:
Test Hole No.:
Depth of Test Hole:
(Pieziometric Surface in inches)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0 50 100 150 200 250 300Infiltration Rate, in/hrTime Elapsed (min)
PERCOLATION TEST DATA SHEET
Carlsbad Station Project No.: 1809‐04 Date: 5/23/2019
P‐3 Tested By: SS Water Temp.: 58
5 ft. USCS: SM/SC Air Temp.: 61
Test Hole Dimensions (Inches)
Length 59 Width 6.5 Diameter 6.5
Infiltration Test
Trial No. Start Time Stop Time Time Interval Average Perc Rate Infiltration Rate*
(hr and min) (hr and min) (min.) Start Depth End Depth Depth Change Water Column (in./hr.) (in./hr.)
1 11:50 12:20 30 24.00 18.25 5.75 21.13 11.50 0.821
2 12:20 12:50 30 24.00 21.00 3.00 22.50 6.00 0.404
3 12:50 13:20 30 23.75 20.50 3.25 22.13 6.50 0.445
4 13:20 13:50 30 23.75 21.25 2.50 22.50 5.00 0.337
5 13:50 14:20 30 23.75 21.25 2.50 22.50 5.00 0.337
6 14:20 14:50 30 24.00 21.75 2.25 22.88 4.50 0.298
7 14:50 15:20 30 23.75 21.50 2.25 22.63 4.50 0.302
8
9
10
11
12
13
14
15
*Calculated via Porchet Method
Project:
Test Hole No.:
Depth of Test Hole:
(Pieziometric Surface in inches)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0 50 100 150 200 250 300Infiltration Rate, in/hrTime Elapsed (min)
Factor Description
Assigned
Weight (w)
Factor
Value (v)
Product (p)
p = w x v
Soil assessment methods 0.25 2 0.5
Predominant soil texture 0.25 2 0.5
Site soil variability 0.25 2 0.5
Depth to groundwater / impervious layer 0.25 2 0.5
2
Level of pretreatment/ expected
sediment loads 0.5 2 1
Redundancy/resiliency 0.25 2 0.5
Compaction during construction 0.25 2 0.5
2Design Safety Factor, SB = Σp
Suitability Assessment Safety Factor, SA = Σp
Appendix D: Approved Infiltration Rate Assessment Methods
Worksheet D.5-1: Factor of Safety and Design Infiltration Rate Worksheet
Factor of Safety and Design Infiltration
Rate Worksheet Worksheet D.5-1
Observed Infiltration Rate, in/hr, Kobserved
(corrected for test-specific bias)
Combined Safety Factor, Stotal=SA x SB 4
Design Infiltration Rate, in/hr, Kdesign = Kobserved / Stotal
Supporting Data
Briefly Describe infiltration test and provide reference to test forms:
Suitability
Assessment
Design
A
B
Factor Category
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
APPENDIX B
BORING LOGS
TOPSOILSilty SAND, fine- to medium-grained, dark reddish brown,slightly moist, loose.
ARTIFICIAL FILLWell graded SAND with silt, fine- to medium-grained,yellowish to reddish brown, moist, medium dense.
Total Depth = 3.1 ft.No groundwater.No caving.Backfilled in accordance with SDCDEH requirements.
SM
SW
NOTES
GROUND ELEVATION 44 ft
LOGGED BY SS
DRILLING METHOD Hand Dug
HOLE SIZE 6.5
DRILLING CONTRACTOR GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 5/23/19 COMPLETED 5/23/19
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
MATERIAL DESCRIPTION
BLOWCOUNTS(N VALUE)GRAPHICLOGDEPTH(ft)0.0
2.5 SAMPLE TYPENUMBERLIQUIDLIMITPLASTICLIMITPLASTICITYINDEXATTERBERGLIMITS
PLASTICITYINDEXDRY UNIT WT.(pcf)MOISTURECONTENT (%)SATURATION (%)FINES CONTENT(%)USCSOTHER TESTSPAGE 1 OF 1
BORING NUMBER P-1
AGS BORING LOG V2 - GINT STD US LAB.GDT - 5/30/19 16:07 - Z:\PROJECT FILES\1809-04 ANTIQUE BLOCK CARLSBAD MCKELLER MCGOWEN\LAB AND BORINGS\1809-04 INFILTRATION LOGS.GPJCLIENT McKellar McGowan, LLC
PROJECT NUMBER 1809-04
PROJECT NAME Carlsbad Station
PROJECT LOCATION Carlsbad, CA
TOPSOILSilty SAND, fine-grained, dark brown, slightly moist, loose;abundant roots.
ARTIFICIAL FILLSilty SAND, fine-grained, brown with grey brown to olivefragments, slightly moist to moist, loose to medium dense.
OLD PARALIC DEPOSITS, UNITS 6-7 (Qop6-7)Silty to clayey SAND, fine-grained, grey brown to olive, ironoxide staining, moist, dense; with black manganese (?)nodules.
Total Depth = 4.1 ft.No groundwater.No caving.Backfilled in accordance with SDCDEH requirements.
SM
SM
SC-SM
NOTES
GROUND ELEVATION 43 ft
LOGGED BY SS
DRILLING METHOD Hand Dug
HOLE SIZE 6.5
DRILLING CONTRACTOR GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 5/23/19 COMPLETED 5/23/19
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
MATERIAL DESCRIPTION
BLOWCOUNTS(N VALUE)GRAPHICLOGDEPTH(ft)0.0
2.5 SAMPLE TYPENUMBERLIQUIDLIMITPLASTICLIMITPLASTICITYINDEXATTERBERGLIMITS
PLASTICITYINDEXDRY UNIT WT.(pcf)MOISTURECONTENT (%)SATURATION (%)FINES CONTENT(%)USCSOTHER TESTSPAGE 1 OF 1
BORING NUMBER P-2
AGS BORING LOG V2 - GINT STD US LAB.GDT - 5/30/19 16:07 - Z:\PROJECT FILES\1809-04 ANTIQUE BLOCK CARLSBAD MCKELLER MCGOWEN\LAB AND BORINGS\1809-04 INFILTRATION LOGS.GPJCLIENT McKellar McGowan, LLC
PROJECT NUMBER 1809-04
PROJECT NAME Carlsbad Station
PROJECT LOCATION Carlsbad, CA
TOPSOILSilty SAND with gravel, fine- to medium-grained, darkbrown, moist, loose; gravel is angular to 1-inch size.
ARTIFICIAL FILLSilty SAND, fine- to medium-grained, dark brown, moist,loose.
OLD PARALIC DEPOSITS, UNITS 6-7 (Qop6-7)Silty to clayey SAND, fine- to medium-grained, grey brownto olive, iron oxide staining, moist, dense.
Total Depth = 4.9 ft.No groundwater.No caving.Backfilled in accordance with SDCDEH requirements.
SM
SM
SC-SM
NOTES
GROUND ELEVATION 41 ft
LOGGED BY SS
DRILLING METHOD Hand Dug
HOLE SIZE 6.5
DRILLING CONTRACTOR GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 5/23/19 COMPLETED 5/23/19
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
MATERIAL DESCRIPTION
BLOWCOUNTS(N VALUE)GRAPHICLOGDEPTH(ft)0.0
2.5 SAMPLE TYPENUMBERLIQUIDLIMITPLASTICLIMITPLASTICITYINDEXATTERBERGLIMITS
PLASTICITYINDEXDRY UNIT WT.(pcf)MOISTURECONTENT (%)SATURATION (%)FINES CONTENT(%)USCSOTHER TESTSPAGE 1 OF 1
BORING NUMBER P-3
AGS BORING LOG V2 - GINT STD US LAB.GDT - 5/30/19 16:07 - Z:\PROJECT FILES\1809-04 ANTIQUE BLOCK CARLSBAD MCKELLER MCGOWEN\LAB AND BORINGS\1809-04 INFILTRATION LOGS.GPJCLIENT McKellar McGowan, LLC
PROJECT NUMBER 1809-04
PROJECT NAME Carlsbad Station
PROJECT LOCATION Carlsbad, CA
OLD PARALIC DEPOSITS (Qop)Silty SAND, fine-grained, reddish brown, moist, mediumdense.
@ 4 ft. grades to yellowish brown.
@ 5 ft. grades to yellowish gray, mottled red, very dense,iron oxide.
@ 10 ft. same, trace clay.
@ 15 ft. grades to yellowish gray, saturated. Groundwater.
@ 20 ft. grades to light reddish gray.
14-26-48(74)
4-10-33(43)
16-23-29(52)
6-50/5"
BU
MC
MC
MC
MC
130
116
120
6.3
13.4
11.2
61
83
77
SM
CONS
CORR
NOTES
GROUND ELEVATION 42 ft
LOGGED BY AB
DRILLING METHOD Hollow Stem Auger
HOLE SIZE 8
DRILLING CONTRACTOR Baja Exploration GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 3/18/19 COMPLETED 3/18/19
AT TIME OF DRILLING 15.00 ft / Elev 27.00 ft
AT END OF DRILLING 11.00 ft / Elev 31.00 ft
AFTER DRILLING ---
MATERIAL DESCRIPTION
BLOWCOUNTS(N VALUE)GRAPHICLOGDEPTH(ft)0
5
10
15
20
25 SAMPLE TYPENUMBERLIQUIDLIMITPLASTICLIMITPLASTICITYINDEXATTERBERGLIMITS
(Continued Next Page)PLASTICITYINDEXDRY UNIT WT.(pcf)MOISTURECONTENT (%)SATURATION (%)FINES CONTENT(%)USCSOTHER TESTSPAGE 1 OF 2
BORING NUMBER B-1
AGS BORING LOG V2 - GINT STD US LAB.GDT - 5/30/19 16:11 - Z:\PROJECT FILES\1809-04 ANTIQUE BLOCK CARLSBAD MCKELLER MCGOWEN\LAB AND BORINGS\1809-04 BORING LOGS.GPJCLIENT McKellar McGowan, LLC
PROJECT NUMBER 1809-04
PROJECT NAME Carlsbad Station
PROJECT LOCATION Carlsbad, CA
SANTIAGO FORMATION (Tsa)Silty SAND, fine-grained, light gray to light grayish brown,moist, very dense.
@ 30 ft. same, trace clay.
@ 35 ft. same.
Total Depth = 35.3 ft.Groundwater encountered during drilling at 15 feet;groundwater measured at completion of drilling at 11 feet.No caving.Backfilled in accordance with SDCDEH requirements.
50/4"
50
50/4"
MC
MC
MC
118
123
122
8.6
10.6
7.8
SM
MATERIAL DESCRIPTION
BLOWCOUNTS(N VALUE)GRAPHICLOGDEPTH(ft)25
30
35 SAMPLE TYPENUMBERLIQUIDLIMITPLASTICLIMITPLASTICITYINDEXATTERBERGLIMITS
PLASTICITYINDEXDRY UNIT WT.(pcf)MOISTURECONTENT (%)SATURATION (%)FINES CONTENT(%)USCSOTHER TESTSPAGE 2 OF 2
BORING NUMBER B-1
AGS BORING LOG V2 - GINT STD US LAB.GDT - 5/30/19 16:11 - Z:\PROJECT FILES\1809-04 ANTIQUE BLOCK CARLSBAD MCKELLER MCGOWEN\LAB AND BORINGS\1809-04 BORING LOGS.GPJCLIENT McKellar McGowan, LLC
PROJECT NUMBER 1809-04
PROJECT NAME Carlsbad Station
PROJECT LOCATION Carlsbad, CA
ASPHALTIC CONCRETE 2 inches AC on native.
OLD PARALIC DEPOSITS (Qop)Silty SAND, fine-grained, reddish brown, moist, mediumdense.
@ 5 ft. grades to yellowish gray, mottled red and black, verydense, iron oxide.
@ 8 ft. grades to light reddish gray, damp.
@ 10 ft. grades to yellowish gray, moist, medium dense.
@ 15 ft. grades to light grayish brown, saturated.Groundwater.
SANTIAGO FORMATION (Tsa)Silty SAND, fine- to medium-grained, light grayish brown,wet, very dense, trace clay.
25-30-41(71)
7-13-15(28)
14-29-50(79)
36-50/3"
BU
MC
SPT
MC
SPT
112 13.9 77
SM
SM
DS
NOTES
GROUND ELEVATION 45 ft
LOGGED BY AB
DRILLING METHOD Hollow Stem Auger
HOLE SIZE 8
DRILLING CONTRACTOR Baja Exploration GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 3/18/19 COMPLETED 3/18/19
AT TIME OF DRILLING 15.00 ft / Elev 30.00 ft
AT END OF DRILLING 13.50 ft / Elev 31.50 ft
AFTER DRILLING ---
MATERIAL DESCRIPTION
BLOWCOUNTS(N VALUE)GRAPHICLOGDEPTH(ft)0
5
10
15
20
25 SAMPLE TYPENUMBERLIQUIDLIMITPLASTICLIMITPLASTICITYINDEXATTERBERGLIMITS
(Continued Next Page)PLASTICITYINDEXDRY UNIT WT.(pcf)MOISTURECONTENT (%)SATURATION (%)FINES CONTENT(%)USCSOTHER TESTSPAGE 1 OF 2
BORING NUMBER B-2
AGS BORING LOG V2 - GINT STD US LAB.GDT - 5/30/19 16:11 - Z:\PROJECT FILES\1809-04 ANTIQUE BLOCK CARLSBAD MCKELLER MCGOWEN\LAB AND BORINGS\1809-04 BORING LOGS.GPJCLIENT McKellar McGowan, LLC
PROJECT NUMBER 1809-04
PROJECT NAME Carlsbad Station
PROJECT LOCATION Carlsbad, CA
SANTIAGO FORMATION (Tsa)Silty SAND, fine- to medium-grained, light grayish brown,wet, very dense, trace clay. (continued)@ 25 ft. grades to fine-grained.
@ 30 ft. same.
Total Depth = 30.8 ft.Groundwater encountered during drilling at 15 feet;gorudnwater measured at completion of drilling at 13.5 feet.No caving.Backfilled in accordance with SDCDEH requirements.
44-50/2"
25-50/4"
SPT
SPT
MATERIAL DESCRIPTION
BLOWCOUNTS(N VALUE)GRAPHICLOGDEPTH(ft)25
30 SAMPLE TYPENUMBERLIQUIDLIMITPLASTICLIMITPLASTICITYINDEXATTERBERGLIMITS
PLASTICITYINDEXDRY UNIT WT.(pcf)MOISTURECONTENT (%)SATURATION (%)FINES CONTENT(%)USCSOTHER TESTSPAGE 2 OF 2
BORING NUMBER B-2
AGS BORING LOG V2 - GINT STD US LAB.GDT - 5/30/19 16:11 - Z:\PROJECT FILES\1809-04 ANTIQUE BLOCK CARLSBAD MCKELLER MCGOWEN\LAB AND BORINGS\1809-04 BORING LOGS.GPJCLIENT McKellar McGowan, LLC
PROJECT NUMBER 1809-04
PROJECT NAME Carlsbad Station
PROJECT LOCATION Carlsbad, CA
OLD PARALIC DEPOSITS (Qop)Silty SAND, fine-grained, reddish brown, moist, mediumdense.
@ 2 ft. grades to grayish brown.
Clayey SAND, fine-grained, light yellowish gray, mottledyellow, very dense.
Silty SAND, fine-grained, light grayish brown, yellow, verydense.
@ 15 ft. grades to light gray, fine- to medium-grained, verydense, saturated, trace coarse sand. Groundwater.
SANTIAGO FORMATION (Tsa)Silty SAND, fine-grained, tan to light yellowish gray, wet,very dense, trace clay.
15-29-49(78)
12-38-50/3"
6-9-20(29)
16-50/5"
SPT
MC
SPT
MC
SM
SC
SM
SM EI
NOTES
GROUND ELEVATION 41 ft
LOGGED BY AB
DRILLING METHOD Hollow Stem Auger
HOLE SIZE 8
DRILLING CONTRACTOR Baja Exploration GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 3/18/19 COMPLETED 3/18/19
AT TIME OF DRILLING 15.00 ft / Elev 26.00 ft
AT END OF DRILLING 9.00 ft / Elev 32.00 ft
AFTER DRILLING ---
MATERIAL DESCRIPTION
BLOWCOUNTS(N VALUE)GRAPHICLOGDEPTH(ft)0
5
10
15
20
25 SAMPLE TYPENUMBERLIQUIDLIMITPLASTICLIMITPLASTICITYINDEXATTERBERGLIMITS
(Continued Next Page)PLASTICITYINDEXDRY UNIT WT.(pcf)MOISTURECONTENT (%)SATURATION (%)FINES CONTENT(%)USCSOTHER TESTSPAGE 1 OF 2
BORING NUMBER B-3
AGS BORING LOG V2 - GINT STD US LAB.GDT - 5/30/19 16:11 - Z:\PROJECT FILES\1809-04 ANTIQUE BLOCK CARLSBAD MCKELLER MCGOWEN\LAB AND BORINGS\1809-04 BORING LOGS.GPJCLIENT McKellar McGowan, LLC
PROJECT NUMBER 1809-04
PROJECT NAME Carlsbad Station
PROJECT LOCATION Carlsbad, CA
SANTIAGO FORMATION (Tsa)Silty SAND, fine-grained, tan to light yellowish gray, wet,very dense, trace clay. (continued)@ 25 ft. same, micaceous.
@ 30 ft. same.
Total Depth = 30.8 ft.Groundwater encountered during drilling at 15 feet;groundwater measured at completion of drilling at 9 feet.No caving.Backfilled in accordance with SDCDEH requirements.
23-43-50/3"
32-50/4"
SPT
MC
MATERIAL DESCRIPTION
BLOWCOUNTS(N VALUE)GRAPHICLOGDEPTH(ft)25
30 SAMPLE TYPENUMBERLIQUIDLIMITPLASTICLIMITPLASTICITYINDEXATTERBERGLIMITS
PLASTICITYINDEXDRY UNIT WT.(pcf)MOISTURECONTENT (%)SATURATION (%)FINES CONTENT(%)USCSOTHER TESTSPAGE 2 OF 2
BORING NUMBER B-3
AGS BORING LOG V2 - GINT STD US LAB.GDT - 5/30/19 16:11 - Z:\PROJECT FILES\1809-04 ANTIQUE BLOCK CARLSBAD MCKELLER MCGOWEN\LAB AND BORINGS\1809-04 BORING LOGS.GPJCLIENT McKellar McGowan, LLC
PROJECT NUMBER 1809-04
PROJECT NAME Carlsbad Station
PROJECT LOCATION Carlsbad, CA