HomeMy WebLinkAboutTract Map 3646 Parcel 4 Geotechnical Wastewater Treatment Report Sims Residence7. z
Earth Strata Geotechnical Services, Inc.
Geotechnical, Environmental and Materials Testing Consultants
R
September 21,2016
Project No. 161329-11A
Confirmation No. PR 3058
Mr.Jason Sims
32564 Via Destello
Temecula,CA 92592
1
Subject: Onsite Wastewater Treatment System Report, Assessor's Parcel Number 922-190-015, Tract
1 Number 3646,Lot Number 4,Located at 29370 Valley Avenue,Temecula Area,Riverside County,
California
Reference: County of Riverside, Community Health Agency, Department of Environmental Health, Onsite
Wastewater Treatment Systems, Technical Guidance Manual,Version A,undated.
Earth Strata Geotechnical Services,Inc.is pleased to present this onsite wastewater treatment system(OWTS)report
for the proposed residential development,referenced above. The purpose of our feasibility study was to determine
the percolation rates and physical characteristics of the subsurface earth materials within the vicinity of the
proposed leach lines. We have provided guidelines for the design of an onsite wastewater treatment system,where
applicable. This evaluation is intended to provide adequate data to satisfy the County of Riverside, Community
Health Agency,Department of Environmental Health guidelines for single-family dwelling approval.
PROPERTY DESCRIPTION AND LOCATION
The subject property is located at 29370 Valley Avenue, in the Temecula area of Riverside County, California (See
Figure 1). The subject property consists of an undeveloped parcel of land with relatively terrain.
PROPOSED CONSTRUCTION
Based on information provided by you,the proposed development includes a single family residence,complete with
an onsite wastewater treatment system.
SUBSURFACE EXPLORATION AND PERCOLATION TESTING
SUBSURFACE EXPLORATION
Subsurface exploration of the subject site consisted of one (1) deep exploratory test hole to a depth of 15 feet,
conducted on September 1, 2016. The deep exploratory test hole was excavated to interpret whether groundwater
or impermeable soil layers were present. Earth materials encountered within the deep exploratory test hole were
classified and logged using the guidelines ofASTM 2487. The approximate location of the deep exploratory test hole
is shown on the attached Percolation Location Map, Plate 1. The exploratory log has been included within Appendix
A.
42217 RIO NFDO ROAD. SUITE A-201. TEMF.C[ILA. CA 92WO 951-397-8315. F.SCSINC.COM
PERCOLATION TESTING
A total of four (4) percolation tests were conducted on September 15, 2016 to evaluate the feasibility of utilizing
leach fields for onsite wastewater treatment. The percolation tests were performed in general accordance with the
referenced guidelines.
The percolation tests were performed at the bottom of 3-3%feet deep test pits in 6- inch diameter tests holes. The
exploratory log and locations of the percolation test holes are indicated on the attached Percolation Location Map,
Plate 1. The percolation and deep exploratory test holes were located by property boundary measurement on the
site plan and by using geographic features. Each percolation test hole was cleaned of loose materials prior to
performing the percolation testing. A 5-gallon water container filled with clear water was then inverted and
supported over each test hole. Upon percolation of all 5 gallons while the tester was present,testing was conducted
on that day. If some of the initial 5 gallons remained while the tester was present, the test was conducted the day
after the presoak,but not more than 26 hours after initiating the presoak
Upon completion of the presoak,testing was performed by adjusting the water level to be 6 inches over the gravel
for six(6)hours or two(2)hours in the case of sandy soils. The drop in water level was measured from a fixed initial
reference point for more reliable readings, with measurements having an accuracy of 0.25-inch. After each
measurement the water level was brought up to approximately 6 inches over the top of the gravel. The final
percolation test reading is summarized in the following table and the test data recorded in the field is included in
Appendix B.
PERCOLATION TEST SUMMARY
TEST HOLE
H
NUMBER DIAMETER
DEPTH PERCOLATION MATERIAL
IN
FT.)RATE (MPI)DESCRIPTION
P-1 8 3 30 Silty SAND
P-2 8 3 IS Silty SAND
P-3 8 3 15 Silty SAND
P-4 8 3.5 30 Silty SAND
FINDINGS
EARTH MATERIALS
A general description of the earth materials observed on site is provided below:
t
Topsoil: Residual topsoil,blankets much of the site. These materials were noted to be generally silty sand
which were very porous.
Quaternary Young Alluvial Valley Deposits (Qyv): The young alluvial valley deposits likely consist of silty,
clayey,and poorly graded sands.
EARTH STRATA GEOTECHNICAL SERVICES 2 September 15, 2016
tProject Number 161329-11A
1
GROUNDWATER
1 Groundwater was not observed within the deep exploratory hole (M W-1) excavated to a depth of 15 feet.
Additional exploration to a depth of 511h feet was conducted for the geotechnical evaluation.The groundwater level
for the deep boring(B-3) was 32 feet.The boring is approximately 200 feet from the proposed leach field area.
PERCOLATION TEST RESULTS
The final measured percolation test design rate is 30 minutes per inch (mpi).
CONCLUSIONS AND RECOMMENDATIONS
GENERAL
tBased on the data presented in this report and using the recommendations set forth, it is the judgment of this
professional that there is sufficient area on the lot to support a primary and expansion OWTS that will meet the
current standards of the Department of Environmental Health and the Regional Water Quality Control Board
RWQCB). The design system shall be located in natural undisturbed soil at the depth of the tests performed. The
natural occurring body of minerals and organic matter at the proposed wastewater disposal area contains earthen
materials having more than 50%of its volume composed of particles smaller than 0.08 inches (2mm) in size.
Based on the data presented in this report and the testing information accumulated, it is the judgment of this
professional that the groundwater table will not encroach within the current allowable limit set forth by County and
State requirements. Although groundwater was encountered at a depth of 32 feet, out interpretation is that
groundwater will not encroach within the current allowable limits since soil mottling was not observed during our
exploration.
SEWAGE DISPOSAL DESIGN RECOMMENDATIONS
tThe proposed sewage disposal system should consist of leach lines utilizing plastic(polyolefin)Standard Infiltrator®
chambers manufactured by Infiltrator® Systems, Inc. The areas for both a primary system and a 100 percent
expansion system are required. Septic tanks should be located upslope from the leach fields to provide gravity flow
tfrom the septic tank to the leach lines. Descriptions of the general design and construction of the wastewater
treatment systems is provided below.
1 Septic Tank Capacity: The minimum septic tank capacity is determined,in accordance with the referenced
guidelines,by the total fixture count within the proposed design.
Allowable Design Percolation Rate: To determine the approximate square footage of each leaching area,
the individual percolation rate test for each area that meet the requirements may be used as a guideline.
Primary System: Primary systems consist of a 2000-gallon septic tank and leach field composed of
subsurface leach lines. The minimum leach field absorption area is based upon the proposed septic tank
capacity and the percolation rate of the proposed leach field area. The dimensions for individual leach field
absorption areas are based on the total trench bottom area only and the areas between the leach line
trenches are not included. In addition, the total linear footage can be reduced by 20 percent for designs
utilizing plastic Infiltrator®chambers,as long as each line is of equal length.
EA]kTR-H STIKATA G E01FIEC:R-I1NICAIL S]ERZYIIC]ES 3 September 15, 2016
Project Number 161329-11A
1
Trench Width, Depth, and Minimum Soil Cover: For leach field areas having a slope of 10 percent, a
minimum soil cover of 1%feet over the leach lines is required. This soil cover is required to maintain a 15
feet minimum horizontal distance from the slope face to any portion of the leach lines. In order to provide a
11h foot soil cover, the trenches should be excavated to a depth on the order of 3 to 3% feet below the
surface. It should be noted that the required depth of cover is greater for those areas where the slope is
steeper than 10 percent.
Individual leach line trenches should be excavated along the contours of the property which will maintain
approximately the same elevation at the top of the trench. The leach line trench should be 18 to 36 inches
wide,with a minimum center to center spacing of 6 to 7 feet,respectively.
1 m
30 65 1,300 1 434 87 348
As a result, the recommended leach field design consists of 348 feet long leach lines with Infiltrator®
chambers per line for both the primary and expansion system disposal areas. The proposed location for each
system shall provide sufficient areas for both primary and 100%expansion.
100 Percent Expansion System: Sufficient area must be set aside for future construction of a backup
system of equal size in the event the primary system fails. The area required for the 100 percent expansion
system is identical to that of the primary system.
ADDITIONAL DESIGN CONSIDERATIONS AND RECOMMENDATIONS
To encourage the maximum loss of sewage effluent through evaporation and transpiration,the leach lines should be
installed at the recommended depth and as close to the ground surface as possible. As noted above, leach lines
should also be installed within trenches excavated along ground contours of equal elevation to maintain a relatively
consistent trench depth. The minimum center to center spacing between the leach line trenches is 7 feet for 36-inch
wide trenches.
Backfill materials placed over the leach lines should not be compacted but slightly mounded to allow for settlement
and to minimize infiltration of surface water. To prevent collapse or crushing of the chambers,cobbles and boulders
should be removed from the backfill soils over the plastic Infiltrator®chambers.
A minimum horizontal clearance of 5 feet is required between the leach lines and property lines. A minimum
horizontal clearance of 5 feet is also required between the septic tank and proposed structures. A minimum
horizontal clearance of 8 feet is required between the leach lines and proposed structures.
In the event that future access to the 100 percent expansion area is compromised by development Cie.,garden walls,
etc.),consideration should be given to constructing the expansion system at the same time as the primary system. If
the systems are not constructed concurrently, consideration should be given to accessibility of the 100 percent
expansion area after all site improvements are constructed.
EARTH STRATA GEOTECHNICAL SERVICES 4 September 15, 2016
1 Project Number 161329-11A
The leach line trenches should be observed by the geotechnical consultant during and after excavation, as well as
before the placement of perforated pipe or plastic Infiltrator®chambers. The site observations are to verify the
suitability of the exposed earth materials. Necessary revisions or modifications may be needed if unforeseen
conditions exposed during construction,such as hard impermeable rock. Revisions could include adding additional
lines or a redesign of the system that conforms to the site conditions.
The leach field areas should not be used for recreation, horse corrals or other uses that would compact the earth
materials at the surface. The ground surface over the disposal areas should be seeded or sodded to mitigate erosion.
The property owners should take note that proper use and maintenance are crucial to extending the effective design
life of the sewage disposal system. The use of excessive water, introduction of detergents or chemicals, and solid
food waste from garbage disposals can cause premature system failures. Properly maintained sewage disposal
systems can function for many years. However, a rest period of roughly 10 to 15 years is generally needed to
promote bacterial decay and a chance to dry up. After this resting period, the primary system can often be
reactivated and alternated with the 100 percent expansion system.
GRADING PLAN REVIEW AND CONSTRUCTION SERVICES
This report has been prepared for the exclusive use of Mr.Jason Sims and their authorized representative. It likely
does not contain sufficient information for other parties or other uses. Earth Strata should be engaged to review the
final design plans and specifications prior to construction. This is to verify that the recommendations contained in
this report have been properly incorporated into the project plans and specifications. Should Earth Strata not be
accorded the opportunity to review the project plans and specifications, we are not responsibility for
misinterpretation of our recommendations.
Earth Strata should be retained to provide observations during construction to validate this report. In order to allow
for design changes in the event that the subsurface conditions differ from those anticipated prior to construction.
Earth Strata should review any changes in the project and modify and approve in writing the conclusions and
recommendations of this report. This report and the drawings contained within are intended for design input
purposes only and are not intended to act as construction drawings or specifications. In the event that conditions
encountered during grading or construction operations appear to be different than those indicated in this report,
this office should be notified immediately,as revisions may be required.
REPORT LIMITATIONS
Our services were performed using the degree of care and skill ordinarily exercised, under similar circumstances,by
reputable soils engineers and geologists, practicing at the time and location this report was prepared. No other
warranty, expressed or implied, is made as to the conclusions and professional advice included in this report.
Earth materials vary in type, strength, and other geotechnical properties between points of observation and
exploration. Groundwater and moisture conditions can also vary due to natural processes or the works of man on
this or adjacent properties. As a result,we do not and cannot have complete knowledge of the subsurface conditions
beneath the subject property. No practical study can completely eliminate uncertainty with regard to the anticipated
geotechnical conditions in connection with a subject property. The conclusions and recommendations within this
report are based upon the findings at the points of observation and are subject to confirmation by Earth Strata during
construction. This report is considered valid for a period of one year from the time the report was issued.
IEARIfIIN STRATA GEOTIECIFINICAIL SERVICES 5 September 15, 2016
Project Number 161329-11A
This report was prepared with the understanding that it is the responsibility of the owner or their representative,
to ensure that the conclusions and recommendations contained herein are brought to the attention of the other
project consultants and are incorporated into the plans and specifications. The owners' contractor should properly
implement the conclusions and recommendations during grading and construction, and notify the owner if they
consider any of the recommendations presented herein to be unsafe or unsuitable.
Respectfully submitted,
EARTH STRATA GEGTECH-HNHCAL SERVICES
Q pfESS/pal
WC14.
ca a-Na. 40219_o m
Exp.
Stephen M. Poole, PE 40219 dit
President
CNIL
OF CAt1F
Principal Engineer
I,Stephen M. Poole, am duly registered in the State of California and hereby attest that I have personally prepared
this report,assume full professional responsibility for its validity,and for any errors or omissions herein.
SMP/snj/kp/mw
Distribution: (2)Addressee
Attachments: Figure 1 -Vicinity Map(Rear of Text)
Appendix A- Exploratory Logs(Rear of Text)
Appendix B - Percolation Test Results(Rear of Text)
Plate 1 - Percolation Location Map(Rear of Text)
t
1
EARTH STRATA GEOTECH'NICAL SERVICES 6 September 15, 2016
Project Number 161329-11A
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SCALE 1740,625
and Materials Testing Consultants SEPT 2016 1 FIGURE 1
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APPENDIX A
EXPLORATORY LOGS
Geotechnical Boring Log MW-1
Date: 9/l/2016 Project Name: Vallego Ave Page: • of "
tProject Number: 161329-11A Logged By:JCF
Drilling Company:Cal Pac Type of Rig: Mobile Drill Rig
tDrive
Weight(lbs): 140 Drop(in): 30 Hole Diameter(in): 8
Fop of Hole Elevation (ft): See Map Hole Location: See Geotechnical Map
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MATERIAL DESCRIPTION
0 Topsoil:
SM Silty SAND;ligh brown,dry,loose,fine to coarse sand
Quaternary Young Alluvial Valley Deposits(Qyv):
5
SM Silty SAND;brown,dry,medium dense,fine to medium sand
Clay nodules at 8 feet
10
SL Clayey SAND;brown,slightly dry,dense,fine to coarse sand
1
15
SP Poorly-Graded SAND, brown slightly dry, dense, fine to coarse sand
Total Depth: 15 Feet
No Groundwater
1 20
25
1 30
Earth .Strata Georechnical Services, Inc.
42217 Rio Nedo Road, Suite A-104, Temecula, CA 92590 Grmmhnaol.F.m vonm naul aml.Hurgials Taeing Comurmns
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APPENDIX B
PERCOLATION TEST RESULTS
PERCOLATION SHEET
Tested By:TJ
Project No.: 161329-11A
Test Hole Number: P-1 Test Hole Diameter(inches): 8
Soil Classification: Silty SAND Date Excavated:9j1/2016
Depth of Test Hole (ft): 3 Date Tested:9/15/2016
Date/Time Presoak Period Amount of Water Used/Comments
Start 9/1/2016 8:00 Time Interval of Presoak
Stop 9/2/2016 8:00 N/A
Time
Time Interval
Elapsed
Time
sed
Initial Water Final Water Water Level Drop Percolation Rate
min.)
p
Level(Inches) Level(Inches) Inches) Min./Inch)
min.)
8:44
30 30 15 19 4.00 7.5
9:14
9:14
30 60 19 23 4.00 7.5
9:44
0:
4
1 :14
30 90 17 18 1.00 30.0
10:14
30 120 18 19 1.00 30.0
10:44
10:44
30 150 19 20 1.00 30.0
11:14
11:14
30 180 20 21 1.00 30.0
11:44
11:44
30 210 14 15.5 1.50 20.0
12:14
12:14
30 240 15.5 17 1.50 20.0
12:44
12:44
30 270 17 17.75 0.75 40.0
13:14
13:14
30 300 17.75 18.5 0.75 40.0
13:44
13:44
30 330 16 17 1.00 30.0
14:14
14:14
30 360 17 18 1.00 30.0
14:44
1
1
MEASURED FROM TOP
PERCOLATION SHEET
Tested By:T1
Project No.: 161329-11A
Test Hole Number: P-2 Test Hole Diameter(inches): 8
Soil Classification: Silty SAND Date Excavated:9/1/2016
Depth of Test Hole (ft): 3 Date Tested:9/15/2016
Date/Time Presoak Period Amount of Water Used/Comments
Start 9/1/2016 8:00 Time Interval of Presoak
Stop 9/2/2016 8:00 N/A
Time Interval Initial Water Final Water Water Level Drop Percolation Rate
Tame:
Time
min.)
Elapsed
Level(Inches) Level(Inches) Inches) Min./Inch)
min.j
8:45
30 30 13 18 5.00 6.0
9:15
9:15
30 60 18 23 5.00 6.0
9:45
9:45
30 90 16 18 2.00 15.0
10:15
10:15
30 120 18 20 2.00 15.0
10:45
10:45
30 150 20 22 2.00 15.0
11:15
11:15
30 180 22 24 2.00 15.0
11:45
11:45
30 210 17 19 2.00 15.0
12:15
12:15
30 240 19 21 2.00 15.0
12:45
12:45
30 270 21 23 2.00 15.0
13:15
13:15
30 300 23 25 2.00 15.0
13:45
13:45
30 330 18 20 2.00 15.0
14:15
14:15
30 360 20 22 2.00 15.0
14:45
1
1
MEASURED FROM TOP
PERCOLATION SHEET
Tested By:TJ
Project No.: 161329-11A
Test Hole Number: P-3 Test Hole Diameter(inches): 8
Soil Classification: Silty SAND Date Excavated:9/1/2016
Depth of Test Hole (ft): 3 Date Tested: 9/15/2016
Date/Time Presoak Period Amount of Water Used/Comments
Start 9/1/2016 8:00 Time Interval of Presoak
Stop 9/2/2016 8:00 N/A
Time Interval
Time
InitialWater Final Water Water Level Drop Percolation Rate
Time Elapsed
min.) hes)vel(Inches) Inches) Min./Inch)
6
9:16
30 30 17 21 4.00 7.5
1
t
9:16
30 60 21 24 3.00 10.0
9:46
9:46
30 90 19 21 2.00 15.0
10:16
10:16
30 120 21 23 2.00 15.0
10:46
10:46
30 150 18 20 2.00 15.0
11:16
11:16
30 180 20 22 2.00 15.0
11:46
11:46
30 210 17 19 2.00 15.0
12:16
12:16
30 240 19 21 2.00 15.0
12:46
12:46
30 270 21 23.5 2.50 12.0
13:16
13:16
30 300 23.5 26 2.50 12.0
13:46
13:46
30 330 17 19 2.00 15.0
14:16
14:16
30 360 19 21 2.00 15.0
14:46
1
MEASURED FROM TOP
PERCOLATION SHEET
Tested By:T1
Project No.: 161329-11A
Test Hole Number: P-4 Test Hole Diameter(inches): 8
Soil Classification: Silty SAND Date Excavated:9/1/2016
Depth of Test Hole (ft): 3.5 Date Tested:9/15/2016
Date IF Time Presoak Period Amount of Water Used/Comments
Start 9/1/2016 8:00 Time Interval of Presoak
Stop 9/2/2016 8:00 N/A
Time
Time Interval Initial Water Final Water Water Level Drop Percolation Rate
Time
min)
Elapsed
Level(Inches vel(Inches) Inc Min./Inch)
8:47
30 30 19 23 4.00 7.5
9:17
t
9:17
30 60 23 26 3.00 10.0
9:47
9:47
30 90 18 20 2.00 15.0
10:17
10:17
30 120 20 22 2.00 15.0
10:47
10:47
30 150 22 23 1.00 30.0
11:17
11:17
30 180 23 24 1.00 30.0
11:47
11:47
30 210 17 18.5 1.50 20.0
12:17
12:17
30 240 18.5 20 1.50 20.0
12:47
12:47
30 270 20 21 1.00 30.0
13:17
13:17
30 300 21 22 1.00 30.0
13:47
13:47
30 330 16 17.5 1.50 20.0
14:17
14:17
30 360 17.5 18.5 1.00 30.0
14:47
1
1
MEASURED FROM TOP
LEGEND
Locations are Approximate
Symbols
0 50'100,
Limits of Report
r O\Percolation Test Location
P-4
RA
PUBLIC TILI>Y Percolation Monitoring Well LocationEMENT
CT 3646 T.D.
MB 57/86_87 Primary Leach Lines
1
67
M r 100%Ezpansion Leach Lines
NOTES:
2500 GALLON
DESIGN RATE=30 MPI
LOADING RATE=65 SOFT/100 GALLONS
a,ati o
TOTAL LENGTH=541 FEET
INFILTRATION CHAMBER(20%REDUCTION)=433 FEET
I
CO p' d PRIMARY:5 LINES @ 87 FEET LONG
INFILTRATION CHAMBERS)
d 100%EXPANSION:5 LINES @ 87 FEET LONG
onrrawgfl
210. 13'
INFILTRATION CHAMBERS)
90,00' 1.2500 Gallon Septic Tank
t 2.Distribution Box
d3.Primary Leach LinesPrz:4.100%Expansion Area
3. 83.84' 231. 17'
I' PERCOLATION MAP
LOCATED AT 29370 VALLEYAVENUE
TEMECULA AREA,RIVERSIDE COUNTY, CALIFORNIA
APN 922-190-015
N PROJECT SIMS RESIDENCE
2'
CLIENT MR.JASON SIMS
PROJECT NO. 161329-11A
DATE SEPTEMBER 2016
SCALE 1:50
n O d DWG XREFS
P-2 O REVISION
4 DRAWN BY JDG PLATE 1 OF 1
VALLEJO AVEAVEN E5C351NC.
Geotechnical, Environmental,
and Materials Testing onsultants