HomeMy WebLinkAboutAppendix F - Infiltration Evaluation
Sampson and Associates
CONSULTING ENGINEERS Soil, Geology, Environmental
TO: SA Golden Investment Inc. 6226 Cooper Avenue
Fontana, California 92336
Project Res. Units February 25, 2022
SUBJECT: Infiltration Evaluation,, 24 Units Residential Units, Located at 8155 Banana Avenue, City Of Fontana, County of San-Bernardino, California.
INTRODUCTION:
We sincerely appreciate the opportunity to be of service to you on this project.
The primary objective of this study was to evaluate an infiltration rate of the onsite
subsurface soils for the design of the infiltration drainage system to be constructed
at designated area for the above subject site.
If you have any questions regarding this report please do not hesitate to contact
this office at your convenience. We appreciate the opportunity to be of service
on this project.
Distribution: ddressee
P. 0. Box 834, San Dimas, California 91773 Tel.: (909) 522-7067
Project Res. Units February 25, 2022
Index Map
Of
8155 Banana Avenue
City Of Fontana County Of San Bernardino, California
Page 2
Project Res. Units February 25, 2022
ACCOMPANYING MAPS & ILLUSTRATIONS,:
Index Map - Page 2
Plate 1 - Site Plan and Approximate Location of Infiltration Tests
Appendix “A” - Field Test Logs
SITE LOCATION, PROPOSED DEVELOPMENT, and CONDITION:
The site area is approximately 38000 square feet and the proposed development consists of (24)
new apartment units each with associated open lawn areas and parking lots located 8155 Banana
Avenue in the City of Fontana County Of San Bernardino, California.
The subject site is flat regular shape lot bounded by Banana Avenue on east and by multi residential on north, south, and west. Access to the site is available from Banana Avenue which
is paved.
Project is covered with minor dry annual weeds, bushes, and minor scattered trash.
SUBSURFACE CONDITIONS:
Soil materials encountered in our trenches consisted of top-soils over alluvium material to a
depth of approximately 12 inches below surface. Upper 2 feet consists of dry, loose, silty sand
with gravels and some rocks with roots and minor trash on surface. The soils below 2 feet is
loose and dry silty sand, sandy silt with minor roots to depth of 4 feet below grade. The soils
encountered below approximately 4 feet grade consists of dense brown silty sand with rocks, cobbles, and boulders.
GROUND WATER:
No ground water or any perched ground water was observed at our test locations onsite during the course of our investigation.
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Project Res. Units February 25, 2022
INFILTRATION TEST:
Shallow percolation tests were performed at the approximate locations of the proposed infiltration
drainage system. Two 8-inch diameter boring holes were drilled to a depth of 3 feet as shown on
grading plan and test location (Plate 1). The bottom elevation of the test hole is corresponded to
the bottom elevation of the proposed infiltration system. The holes were filled with water and left for presoaking period.
TEST PROCEDURE:
Once the minimum required numbers of testing intervals were determined, water was added. The time and the drop in water level were recorded until the stabilized rate of drop was obtained. The average drop of the stabilized rate over the last readings is the pre-adjusted percolation rate at
the test location. Logs of field data are presented in Appendix “A” of this report.
The design engineer must use the factor of safety with the average measured infiltration rate to
achieve the design value as needed.
RECOMMENDATIONS:
Bases on the result of the tests, the site is suitable for the storm-water infiltration system from a
geotechnical viewpoint. Recommendations are provided as follows:
1- The on-site storm-water infiltration drainage system may be designed utilizing the slowest conservative infiltration rate of 7.00 inches per hour after the rate of percolation was
generally stabilized.
2- The potential for creating perched water conditions that may adversely affect the proposed
and existing structures is nil due to the onsite permeable soils. 3- It must be noted that over the lifetime of the disposal area the infiltration rate may be
affected by sediment build ups and biological activities as well as local variation in soils
subsurface condition.
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Project Res. Units February 25, 2022
LIMITATONS:
Based on our visual observation it appears that the soils condition appears to be the same throughout
the site however; soils material may vary in character between excavations and natural outcrops or conditions exposed during construction. Should soil conditions be encountered during construction that appear different this office must be notified immediately so that our recommendations may be
re-evaluated.
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Project Res. Units February 25, 2022
A P P E N D I X “A”
Plate-1
Approximate Location Of Infiltration Test
Plate-1 Approximate Location Of
Infiltration Test Map
8155 Banana Avenue
Project Res. Units February 25, 2022
PERCOLATION TESTING FIELD LOG
Boring/Excavation Percolation Testing Field Log Date: 02/19/2022
Project Location 8155 banana Ave. Boring/test Number: B-1
Earth Description: Silty Gravelly Sand Diameter of Boring: 8-inch
Tested by: TB/MS Depth of Boring: 3’ below grade
Depth to Invert of BMP’s: 3’ below grade
Liquid Description: Tap Water Depth to Water Table: >50’
Measurement Method: Measuring Tape Depth to initial water Depth(d1): 36”
Time Interval Standard:
Start Date for Pre-Soak: 02/19/2022 Water Remaining In Boring (Y/N): Yes
Start Time for Standard: 11:00 Standard Time Interval
Between Readings: 30 Minutes
Reading
Number
Time
Start/End
(hh:mm)
Elapsed
Time
Time
(mins)
Water
Drop
During
Standard
Time
Interval
D
(inches)
Percolation
Rate for
Reading
(in/hr)
Soil Description/Notes/Comments
1
11:00
30
6.75
13.50
Medium to Coarse, Silty Gravelly Sand 11:30
2 12:00
30
5.75
11.50
12:30
3
13:00
30
5.5
11.0
13:30
4
14:00
30
4.25
8.50
14:30
5
15:00
30
3.50
7.00
15:305
Infiltration
Rate
7.00 In/Hr.
Use 7.0
Project Location: 8155 Banana Ave. Project No: Res. Units PLATE-2
Project Res. Units February 25, 2022
PERCOLATION TESTING FIELD LOG
Boring/Excavation Percolation Testing Field Log Date: 02/19/2022
”
Time Interval Standard:
Start Date for Pre-Soak: 02/19/2022 Water Remaining In Boring (Y/N): Yes
Start Time for Standard: 11:20 Standard Time Interval
Between Readings: 30 Minutes
Reading Number Time Start/End
(hh:mm)
Elapsed Time Time
(mins)
Water Drop During
Standard
Time
Interval
D
(inches)
Percolation
Rate for
Reading
(in/hr)
Soil Description/Notes/Comments
1
11:20
30
4.75
8.50
Medium to Coarse, Silty Gravelly Sand 11:50
2 12:55
30
4.50
9.00
13:25
3
13:30
30
4.50
9.00
14:00
4
14:05
30
4.25
8.50
14:35
5 14:40
30
3.75
7.50
15:10
6
15:15
15:45
30
3.75
7.50
Infiltration
Rate
7.50 In/Hr.
Use 7.50 in/hr
Project Location: 8155 Banana Ave Project No: Res. Units PLATE-3
Project Location 8155 banana Ave. Boring/test Number: B-2
Earth Description: Silty Gravelly Sand Diameter of Boring: 8-inch
Tested by: TB/MS Depth of Boring: 3’ below grade
Depth to Invert of BMP’s: 3’ below grade Liquid Description: Tap Water Depth to Water Table: >50’
Measurement Method: Measuring Tape Depth to initial water Depth(d1): 36