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CIVIL ENGINEERINGIPLANNINGICADD
DRAINAGE CALCULATIONS FOR:
PAW Subdivision
PROJECT NO: C2020-018
S\pNAL FNGi
�\�E N SFa �'F� DATE: 09/20/2022
Q� 09/21/2022 -;0
20218
Developer:
`gyp F of ��P Q� Biltmore Company
1580 W. Cayuse Creek Dr.
Meridian, ID 83646
1119 E. State St., Suite 210 ♦ Eagle, Idaho 83616 ♦ Tel.: 208-938-0013
PAW Subdivision consists of approximately 4.77 acres. Earthwork will consist of excavation for
the site's drainage facilities and preparation of the site's drive aisles and building pads. According
to the Geotechnical Report by Allwest, dated 02/22/2021 (& subsequent groundwater monitoring)
groundwater is present and will likely rise during irrigation season. The subsequent groundwater
monitoring shows that groundwater has risen during irrigation season. It should be noted that the
initial reading elevations have been considered inaccurate due to active irrigation of the adjacent
property. The site has been designed to provide adequate separation to the bottom of drainage
facilities.
The site has been designed with a variety of public & private drainage systems. Public systems
include a "zero-separation" infiltration basin and a vertical sand lens. Private systems include
pervious concrete, infiltration swales, vertical sand lenses, and an infiltration pond.
Per Meridian City Code,no sand lenses are allowed in required landscape areas;rather bioretention
soil mixture (BSM) will be utilized to maintain plantings but still allow for infiltration. The
infiltration rate for BSM is 5 in/hr. A native infiltration rate of 4 in/hr has been used throughout
design, acting as the limiting layer rather than the BSM.
ACHD Drainage Calculations:
The ACHD Calculation Spreadsheet, Version 10.5 (November 2018) was used to determine runoff
volumes and size the site's public drainage facilities.Using a typical estimated time of concentration of
10 minutes and a weighted runoff coefficient for all of the drainage areas, runoff volumes and peak
flows were calculated for each drainage area. All pipes have been designed to provide gravity flow
capacity for the calculated 100-year peak flow rates.A"Pipe Flow Calculations"worksheet is included
(Attachment 2). Public drainage areas also include the front half of adjacent buildable lots. The front
half of these lots are designed to slope towards the roadway before flowing in roadside gutters to the
drainage facilities.
Private Drainage Calculations:
The Boise City Standard Method,using 1.0 inches of rainfall from a 50-year, one-hour storm,was
used to determine the peak volume required for all private drainage areas. The 25 and 50 year peak
flow rates were determined using Q=CiA, with a time of concentration of 10 minutes for areas to be
routed. Pipe flows were checked using Manning's Equation showing that all subsurface storm drain
lines are capable of a gravity flow regime in the 50-year storm event.
Asphalt drive aisles are sloped at 1% to 4% towards infiltration facilities or catch basins located
across the development site. Subsurface storm drainage piping connects these catch basins,routing
towards sand and grease traps.Water that has been routed is treated in sand and grease traps before
entering one of the site's two(2)private vertical sand lenses. These vertical sand lenses have been
designed using a combination of ACHD Policy and Boise City Policy. ACHD Policy calls for the
larger chamber to serve the 100-year storm while the smaller chamber serves the 2-year storm. As
Boise City does not have guidance for these facilities within its' policy, the vertical sand lens has
been designed following ACHD policy with the exception of the larger chamber serving the 50-
year storm (similar to other Boise Policy solutions).
It should be noted that some portions of the parking drain directly into shallow infiltration facilities
(private swales & 1 private pond).
Methodology and Assumptions
1. Geotechnical Report from Allwest,dated 02/22/2021 is attached(Attachment 4)
a. Bedrock is not expected to be encountered.
b. Groundwater is anticipated at relatively shallow depths during the irrigation season;
groundwater monitoring is ongoing.
2. Calculations for ACHD storm water facilities.
a. Rational Method used for peak flows: Qp =CiA
i. Qp =Peak flow for 100 year design storm at storm duration equal to time
of concentration.
1. C =Weighted runoff coefficient based on land use (Attachment 2)
a. C for primarily asphalt drainage area-- 0.95
2. i =Rainfall intensity of design storm in inches/hour—Intensity-
Duration-Frequency table (Attachment 2)
3. A=Area of drainage basin under consideration
ii. Runoff Volume Calculation
1. V=CIAT
a. C =Weighted runoff coefficient
b. I=Rainfall intensity for 1 hour storm
i. i =0.96 in/hr for 100 year storm
ii. i=0.69 in/hr for 25 year storm
iii. i =0.26 in/hr for 2 year storm (vertical sand lens
only)
c. A=Area of drainage in acres
d. T=Duration of storm of 1 hour
3. Calculations for Private Storm Water Facilities
a. Rational Method used for peak flows: Qp =CiA
i. Qp =Peak flow for 50-year design storm at 1 inch of rainfall over 1 hour.
1. C =Runoff coefficient based on land use (Attachment 3)
a. C for roof, concrete & asphalt=0.95
b. C for landscape area=0.20
2. i =Rainfall intensity of design storm in inches/hour—Intensity-
Duration-Frequency table (Attachment 3)
A=Area of drainage basin under consideration—The site is
divided into basins as shown on attached drawing based on final site
grading. (Attachment 1)
ii. Runoff Volume Calculation
1. V=CIAT
a. C =Weighted runoff coefficient based on land use
(Attachment 3)
b. I=Rainfall intensity for 50-year, 1 hour storm=1.0 in/hr,
2-year, 1 hour storm=0.4 in/hr
c. A=Area of drainage in acres
d. T=Duration of storm of 1 hour= 3600 seconds
2. Calculation can be seen in Attachment 3
b. Infiltration Swale Sizing calculations
i. No infiltration during design storm
ii. Infiltration Material Rate: BSM: 5.0 in/hr.
iii. Design Infiltration Rate: 4.0 in/hr
iv. System designed to drain in less than 48 hours
c. Sand and Grease Trap Calculations
i. Size for 50-Year Peak flow
ii. Vault size: 1000 gallon or 1500 gallon
iii. Baffle Spacing: 20 inches
iv. Throat Width: 48 inches or 60 inches
v. Velocity must be less than 0.5 ft/sec
vi. Calculation can be seen in Attachment 3
List of Attachments:
1. Drainage Map
2. Public Drainage Calculations:
a. IDF Curve
b. Weighted Runoff Calculations
c. Pond& Vertical Sand Lens Calculations
d. Pipe Flow & SG Trap Calculations
3. Private Drainage Calculations
a. IDF Curve
b. Runoff Calculations
c. Storage Facility Calculations
d. Pipe Flow & SG Trap Calculations
4. Geotechnical Report & Groundwater monitoring
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09-20-2022
30 0 15 30 60 PROJECT:
C2020-018
SCALE IN FEET SHEET
1"=30' AP
BOISE AREA INTENSITY-DURATION-FREQUENCY,WITH REVISED IDF CURVES
Intensity(inches per hour)
Design Storm 2 5 10 25 50 100
Tc
0.17 10 min 0.69 1.15 1.45 1.85 2.20 2.58
0.25 15 min 0.59 0.97 1.22 1.56 1.86 2.18
0.33 20 min 0.49 0.81 1.01 1.30 1.54 1.81
0.42 25 min 0.43 0.71 0.89 1.14 1.35 1.58
0.50 30 min 0.41 0.67 0.85 1.08 1.29 1.51
0.58 35 min 0.34 0.56 0.70 0.90 1.07 1.25
0.67 40 min 0.31 0.51 0.64 0.82 0.98 1.15
0.75 45 min 0.29 0.48 0.60 0.77 0.91 1.07
0.83 50 min 0.27 0.45 0.56 0.72 0.85 1.00
0.92 55 min 0.26 0.43 0.54 0.69 0.82 0.96
1.00 1 hour 0.26 0.43 0.54 0.69 0.82 0.96
2.00 2 hours 0.16 0.25 0.31 0.39 0.46 0.54
3.00 3 hours 0.13 0.19 0.23 0.29 0.34 0.40
6.00 6 hours 0.09 0.12 0.14 0.18 0.21 0.25
12.00 12 hours 0.06 0.08 0.10 0.12 0.14 0.16
24.00 24 hours 0.04 0.06 0.06 0.08 0.09 0.10
Boise Area
Intensity Duration Frequency (IDF)
3.00
------.2year
2.50 -*-5 year
22.00 -x-10 year
y -6 25 year
s
c1.50 X\ 50 year
r
t/1 X --0-100 year
21.00 --*\
X....................... \
0.50 ��X\
0.00
10 min 15 min 30 min 1 hour 2 hours 3 hours 6 hours 12 hours 24 hours
Duration in minutes and hours
https://baileyengineers.sharepoint.com/sites/BEI-Server-1/Server Folders/C2020-018 Pavilion at Windsong(fka Adelade,
Ustick& Linder)- Biltmore/100 Phase 1/Construction/Calcs/PAW ACHD Drain Calcs 9/20/2022, 2:34 PM
Version 10.0, May 2018
ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method
NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology.These
calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted.
rge Rate using th r post-developm
alculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name PAW Subdivision,DA Pl
2 Is area drainage basin map provided? YES
(map must be included with stormwater calculations)
3 Enter Design Storm(300-Year or 25-Year With 300-Year Flood Route) 100
4 Enter number of storage facilities(25 max) 2
Click to Show More Subbasins ❑
Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin
1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 30
5 Area of Drainage Subbasin(SF or Acres) SF 24,493 1,676
Acres 0.60
6 Determine the Weighted Runoff Coefficient(C) 0.95 0.20
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.90
7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 user Calculate
min i0 Min. Estimated Runoff Coefficients for Various Surface
Type of Surface Runoff Coefficients"I
8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 in/hr Business
Downtown areas 0.70-0.95
9 Calculate the Post-Development peak discharge(QPeak) QpeA 1.40 ifs Urban neighborhoods 0.50-0.70
Residential
Single Family 0.35-0.50
10 Calculate total runoff vol(V)(for sizing primary storage) V 1,873 ft Multi-family 0.60-0.75
V=Ci(Tc=60)Ax3600 Residential(rural) 0.25-0.40
11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70
Industrial and Commercial
Enter Percentile Storm I(95th percentile=0.60 in) 95th 0.60 in Light areas 0.80
Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 1,170 W Heavy areas 0.90
12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Parks,cemeteries 0.
Playgrounds 0.20-0.0-0.35
5
Railroad yard areas 0.20-0.40
13 Volume Summary Unimproved areas 0.10-0.30
Surface Storage:Basin Streets
Asphalt 095
Basin Foreba V 187 ft' .
Y Concrete 0.95
Primary Treatment/StorageBasin V 1,685 ft' Brick 0.95
Subsurface Storage Roofs 0.95
Gravel
Volume Without Sediment Factor(See BMP 20 Tab) V 1,873 ft'
Fields:Sandy soil Soil Soil Type
Slope A B C D
Flat:0-2% 0.04 0.07 0.11 0.
Average:2-6% 0.09 0.12 0.15 0.
Steep:>6% 0.13 0.18 0.23 0.
Adapted from ASCE
https://baileyengineers.sharepoint.com/sites/BEI-Server-1/Server Folders/C2020-018 Pavilion at Windsong(fka Adelade,Ustick&Linder)-Biltmore/100 Phase 1/Construction/Calcs/PAW
ACHD Drain Calcs 9/20/2022,2:35 PM
Version 10.5,November 2018
ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method
NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology.These
calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted.
rge Rate using th r post-developm
Iculate Post-Development Flows(for pre-development flows,increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name PAW Subdivision,DA P2
2 Is area drainage basin map provided? YES
(map must be included with stormwater calculations)
3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100
Click to Show More Subbasins ❑
Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin
1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10
5 Area of Drainage Subbasin(SF or Acres) SF 7,366 2,984
Acres 0.24
6 Determine the Weighted Runoff Coefficient(C) 0.90 0.95
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.91
7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 user calculate
min 10 Min. Estimated Runoff Coefficients for Various Surface
Type of Surface Runoff Coefficients"I
8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 in hr Business
Downtown areas 0.70-0.95
9 Calculate the Post-Development peak discharge(QPeak) Qpealc 0.56 cfs Urban neighborhoods 0.50-0.70
Residential
Single Family 0.35-0.50
10 Calculate total runoff vol(V)(for sizing primary storage) V 751 ft Multi-family 0.60-0.75
V=CI(Tc=60)Ax3600 Residential(rural) 0.25-0.40
11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70
Industrial and Commercial
Enter Percentile Storm I(95th percentile=0.60 in) 95th 0.60 in Light areas 0.80
Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 469 ft' Heavy areas 0.90
12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs Parks,Cemeteries 0.10-0.25
Playgrounds 0.20-0.35
Railroad yard areas 0.20-0.40
13 Volume Summary Unimproved areas 0.10-0.30
Surface Storage:Basin Streets
Basin Foreba V 75 ft` Asphalt 0.95
Y Concrete 0.95
Primary Treatment/StorageBasin V 676 ft' Brick 0.95
Subsurface Storage Roofs 0.95
Volume Without Sediment Factor(See BMP 20 Tab) V 751 ft Gravel 0.75
Fields:Sandy soil Soil Type
Slope A B C D
Flat:0-2% 0.04 0.07 0.11 0.
Average:2-6% 0.09 0.12 0.15 0.
Steep:>6% 0.13 0.18 0.23 0.
Adapted from ASCE
https://baileyengineers.sharepoint.com/sites/BEI-Server-1/Server Folders/C2020-018 Pavilion at Windsong(fka Adelade,Ustick&Linder)-Biltmore/100 Phase 1/Construction/Calcs/PAW
ACHD Drain Calcs 9/20/2022,2:37 PM
Version 10.5,November 2018
ACHD Calculation Sheet for Sizing Basins
NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's
calculation methodology.These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or
exceed these calculations in order to be accepted.
User input in yellow cells.
1 Project Name PAW Subdivision,DA P1
2 Enter number of Basins(25 max) 1
3 Number of Cells(Forebay+Primary=2,Primary Only=1) 2
4 Design Storm 100 Link to: Qv
5 Weighted Runoff Coefficient C 0.90 Q V2 n
QV TR55
6 Area A(Acres) 0.60 acres
7 Approved Discharge Rate(if applicable) 0.00 cfs
8 1-Basin Forebay V 187
Toggle between Forebay and Primary Basin,enter data and print for each
SideSkpe Z site Slope Z Sib Sksz
A ✓ k7mv
SkS,hPz
t--�--� ( ) Side S*Z 6i
Forebay Primary Basin
9 Select Forebay Shape 5-Irregular
10 Width of Forebay Bottom W 0.0 ft 0.0
11 Length of Forebay Bottom L 0.0 ft 0.0
12 Side Slopes(H:1) H:1 3.00 0.00
13 Enter Bottom Elevation 2566.35 ft 2566.10
14 Enter Top Bank Elevation 2568.40 ft 2568.40
15 Enter Water Surface Elevation(WSE) 2567.90 ft 2567.90
16 Distance Between Forebay and Primary Basin(blank if na) 0.00 ft 0.00
17 Enter Elevation Berm 0.00 ft 0.00
18 Enter High Groundwater Elevation 0.00 ft 0.00
19 Min.Freeboard Requirement 0.50
20 Freeboard Provided
21 Infiltration Area for Forebay Infiltration? 4.00 in/hr Note:infiltration required if
Design Infiltration Rate,Enter 0 for no infiltration bottom sloped%or 0 outflow
22 Infiltration Area for Forebay As-d 0 ftz 699
Enter 0 for no infiltration
23 Adjusted Storage Required
260
m Duration i total Q Runoff Perc Vol Pre-Dev Total Max Vol
Vol Discharge Discharge Reqd
Hr in/hr cfs ft3 ft3 ft3 ft3 ft3 1.00 0.96 0.33 187 0 0 1 0 1 187
24 Depth-Storage Relationship:
Saved Surface
Basin Basin Surface Surface Area A at Volume
Saved Side Slope Width at Length at Area A at Area A at Stage(ft2) Below
Stage(ft) New Stage(ft) (H:V) Stage(ft) Stage(ft) Stage(ftz) Stage(ft) OVERIDE Stage(ft)
2566.35 2566.35 3.000 0.0 0.0 Override 217.00 0
2567.90 3.000 0.0 0.0 Override 607.00 639
1.55 ft depth for storage STORAGE OK
25 Does forebay have capacity?
26 Time to drain forebay 0.0 hours
90%volume in 48-hours minimum -
https:Hbaileyengineers.sharepoint.com/sites/BEI-Server-1/Server Folders/C2020-018 Pavilion at Windsong(fka Adelade,Ustick&Linder)-Biltmore/100 Phase 1/Construction/Calcs/PAW ACHD Drain
Calcs 9/20/2022,2:40 PM
Version 10.0,May 2018
ACHD Calculation Sheet for Sizing Basins
NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's
calculation methodology.These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or
exceed these calculations in order to be accepted.
User input in yellow cells.
1 Project Name PAW Subdivision,DA P1
2 Enter number of Basins(25 max) 1
3 Number of Cells(Forebay+Primary=2,Primary Only=1) 2
4 Design Storm 100 Link to: Qv
5 Weighted Runoff Coefficient C 0.90 Q V2 n
QV TR55
6 Area A(Acres) 0.60 acres
7 Approved Discharge Rate(if applicable) 0.00 cfs
8 2-Primary Treatment/Storage V 1,685 ft3
Toggle between Forebay and Primary Basin,enter data and print for each
Sib Sksz
*M.ks,kpz
A Fi-
n.
t--�--� ( ) side S*Z 6i
Primary Basin
9 Select Primary Basin Shape 5-Irregular
10 Width of Primary Basin Bottom W 0.0 ft
11 Length of Primary Basin Bottom L 0.0 ft
12 Side Slopes(H:1) H:1 0.00
13 Enter Bottom Elevation 2566.10 ft 256 .
14 Enter Top Bank Elevation 2568.40 ft 2568.
15 Enter Water Surface Elevation(WSE) 2567.90 ft 2567.90
16 Distance Between Forebay and Primary Basin(blank if na) 0.00 ft 0.00
17 Enter Elevation Berm 0.00 ft 0.00
18 Enter High Groundwater Elevation 0.00 ft 0.00
19 Min.Freeboard Requirement 0.50
20 Freeboard Provided
21 Infiltration Area for Primary/Storage Basin Infiltration? 4.00 in/hr Note:infiltration required if
Design Infiltration Rate,Enter 0 for no infiltration bottom sloped%or 0 outflow
22 Infiltration Area for Primary As-d 699 ftz 0
Enter 0 for no infiltration
23 Adjusted Storage Required
260
m Duration i total Q Runoff Perc Vol Pre-Dev Total Max Vol
Vol Discharge Discharge Reqd
Hr in/hr cfs ft3 ft3 ft3 ft3
3
3 1.00 0.96 0.20 1,685 233 0 233 1,452
24 Depth-Storage Relationship:
Saved Surface
Basin Basin Surface Surface Area A at Volume
Saved Side Slope Width at Length at Area A at Area A at Stage(ft2) Below
Stage(ft) New Stage(ft) (H:V) Stage(ft) Stage(ft) Stage(ftz) Stage(ft) OVERIDE Stage(ft)
2566.10 2566.10 0.000 0.0 0.0 Override 699.00 0
2567.90 0.000 0.0 0.0 Override 1513.00 1,991
1.80 ft depth for storage STORAGE OK
25 Does primary/storage basin have capacity? =,&5
26 Time to drain primary/storage basin 6.5 hours
90%volume in 48-hours minimum -
https:Hbaileyengineers.sharepoint.com/sites/BEI-Server-1/Server Folders/C2020-018 Pavilion at Windsong(fka Adelade,Ustick&Linder)-Biltmore/100 Phase 1/Construction/Calcs/PAW ACHD Drain
Calcs 9/20/2022,2:41 PM
Version 10.0,May 2018
PAW Subdivision, Vertical Sand Filter Calculations (ACHD BMP 21)
9/20/2022
Vertical Sand Filter
2-Year Storm 100-Year
Facility V2 cu ft Depth ft Width ft ids Vo Reg.Length(ft) Used Length Capacity(ft^3) V100(cu ft) De th ft Width ft Voids Reg.Length(ft) Used Length(ft) Capacity
IL
ft^3
Vertical Sand Filters 2 203 3 3.0 0.4 56 66 238 751 3 9.5 0.4 66 66 752
(Public)
PAW Storm Drainage Pipe Flow Calculations (Public)
Updated: 9/20/2022
Formulas:
Mannings Equation: Q 1.486 2/s 1/2
V=A=n Rh S
Where: Area,A=a D2
Wetted Perimeter,P=rrD
Hydraulic Radius,Rh=P
Mannings N Minimum Design slopes
PVC 0.012 12 in 0.22
MID 0.022 15 in 0.15
Concrete 0.014 18 in 0.12
21 in 0.1
24 in 0.08
Wetted
Pipe Run Drainages Storm Event CFS Pipe Size(in) Pipe Slope Area(ft'2) Perimeter Hydraulic Full Flow Flow Check
(Yr) ft) Radius(ft) Percentage (Cap>Req)
CB P1 to Pond P1 P1 100 1.57 12 0.22% 0.785 3.14 0.25 1.81 86.77% OK
CB P2A to CB P213 P2A 100 0.39 12 0.22% 0.785 3.14 0.25 1.81 21.55% OK
CB P213 to SG Trap P2 P2A,P26 100 0.56 12 22.00% 0.785 3.14 0.25 18.09 3.09% OK
ACHD Calculation Sheet for Sand/Grease Traps
NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must
result in facilities that meet or exceed these calculations in order to be accepted.
User input in yellow cells.
1 Project Name PAW Subdivision,SG Trap P2
2 Enter number of Sand/Grease Traps(25 max) 1
Number of Peak Flow Baffle Throat Velocity Is the
Vault Size Spacing width Area(ftZ) 0.5 fps Velocity
S/G Traps Q-cfs inch inch max. ok?
1000 G 1 0.56 20 48 6.67 0.08
Reference for Throat widths(inch)
ADS
Boise Lar-ken WQU,
Vault BMP 16
1000 G 48.0 50.5 n/a
1500 G 60.0 61.5 n/a
WQU1000 n/a n/a 60
WQU1500 n/a n/a 60
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Linder)-Biltmore/100 Phase 1/Construction/Calcs/PAW ACHD Drain Calcs 9/20/2022,2:53 PM
Version 10.0, May 2018
Hydrologic and Hydraulic Graphs APPENDIX D
10.0
8.0
6.0
4.0
2.o
1.7
RUNOFF EVENT
FREQUENCY IN YEARS
1.0
O 0.8
°C
W O.6
d
Uj
= 0.4 S S�
Z I�
Z
} 0.2
Z *INDICATES MAXIMUM PRECIPITATION
Uj AT BOISE WEATHER STATION
~ BETWEEN 1902 AND 1961
Z
0.] INN
.08
.o6
.o4
.o2
10 12 15 20 30 40 50 60 2 3 4 S 6 8 10 12 18 24
MINUTES 0 1 HOURS
DURATION
FIGURE D.1 RAINFALL INTENSITY, DURATION AND FREQUENCY RELATIONSHIP
2019 Boise Stormwater Design Manual p-�
PAW Drainage Calculations
Updated: 9/20/2022
Weighted Runoff Coefficient Time of Concentration 50 cfsV2 Vertical Sand V50 Combined (cu
Drainage Area Area sf Area (acres) 25 cfs 50 cfs Combined at SG V50 cu ft Drains to....
T
(estimated) (min) (estimated) ra Lens Only)
p
1 8115 0.186 0.95 10 0.39 0.46 - - 637 Pervious 1 637
2 4394 0.101 0.95 10 0.21 0.25 - - 345 Pervious 2 345
3 4215 0.097 0.95 10 0.20 0.24 - - 331 Swale 3 (trapezoidal) 331
4 2252 0.052 0.80 10 0.09 0.11 - - 149 Swale 4 (trapezoidal) 149
5A 24542 0.563 0.90 10 1.12 1.32 1.66 730 1825
5B 6354 0.146 0.90 10 0.29 0.34 189 473
Vertical Sand Lens 5 4792
Sc 17850 0.410 0.90 10 0.81 0.96 1.80 531 1328
5 D 15681 0.360 0.90 10 0.71 0.84 467 1166
6A 8782 0.202 0.95 10 0.42 0.50 276 689
6B 2173 0.050 0.95 10 0.10 0.12 0.93 68 171 Vertical Sand Lens 6 1285
6C 4197 0.096 0.95 10 0.20 0.24 132 330
6D 1213 0.028 0.95 10 0.06 0.07 38 95
7 9626 0.221 0.60 10 0.29 0.34 - - 477 Swale 7 477
8 7392 0.170 0.60 10 0.22 0.26 - - 367 Swale 8 367
9 15482 0.355 0.80 10 0.63 0.74 - - 1024 Pond 9 1024
Boise IN
Tc 2-Year 25-Year 50-Year
10 1.0 2.20 2.60
15
20
25
30
35
40
45
50
55
60 0.4 1.00
Vertical Sand Filter
Swales/Ponds Seepage Beds/Pervious Pavement 2-Year Storm 50-Year
Infiltration Rate Depth at HW Time to Drain(hrs)148- Time to Drain hrs Used Length Ca acl
Facility Infiltration Area IsFl Area at HW Line IsFl Capacity Icu ftl De h ft Width ft Length k Capacity V2<u ft Depth k Width ft Voids Rea.Length(ftl Capacity(k^31 V50 cu ft Depth ft Width ft Voids Rea.Length Iftl Used Length Iftl ty
in hr Line Ik1 hours mail 48 max Lftl ft^3
Pervious 1 4 2 7 114 2.4
Pervious 2 4 2 7 62 2.4 34
_ _ _ _ _
Swale 3 4 500 2041 1.00 2.0
_ _ _ _ _
Swale 4 4 119 376 0.67 16 3.8
Vertical Sand Lens 4 _ _ _ - - 1917 4 13.50 0.4 89 90 1944 4792 4 34.00 0.4 88 EA
5
Vertical Sand
4 - - - - - - - - - - 514 3 12 0.4 36 37 633 1285 3 29 0.4 37 37 1288
Lense 6
Swale 7 4 See attached calcs-Swales include subsurface storage
Swale 11 4 See attached calcs-Swales include subsurface storage
Pond 9 4 440 1098 1.50 1364 7,0 - - - - - - - - - - - - - - - - - -
PAW Subdivision Swale Calculations
Surface Swale Calculations Void Calculations Capacity/Drain Time Summary
Infiltration Infiltration Surface Subsurface Subsurface Subsurface Subsurface
Infiltration Infiltration Width Water Unit Area Length Swale Total Capacity Capacity Vs Time to Drain
Swale Name Area Length Area Width Void Ratio Swale Length Swale Width Swale Depth Swale Capacity V50(cu ft)
(ft) (ft) Area (sf) Rate(in/hr) (ft) Depth (ft) (cu ft/ft) (ft) Capacity(cu (LF) (ft) (ft) (cf) (cf) V50 (hrs) (48 max)f
7 40 2 240 4.0 10 1.67 8.33 40 333 0.20 120 2 3 144 477 473 Ok 5.9
8 43 2 244 4.0 10 1.67 8.33 43 358 0.20 122 2 3 146 505 367 Ok 4.5
PAW Storm Drainage Pipe Flow Calculations
Updated: 9/20/2022
Formulas:
Mannings Equation: Q 1.486 2/s 1/2
V=A=n Rh S
Where: Area,A=a D2
Wetted Perimeter,P=rrD
Hydraulic Radius,Rh=P
Mannings N Minimum Design slopes
PVC 0.012 12 in 0.22
MID 0.022 15 in 0.15
Concrete 0.014 18 in 0.12
21 in 0.1
24 in 0.08
Wetted
Pipe Run Drainages Storm Event CFS Pipe Size(in) Pipe Slope Area(ft^2) Perimeter Hydraulic Full Flow Flow Check
(Yr) (ft) Radius(ft) Percentage (Cap>Req)
Max Combined Flow 5C&5D 50 1.80 1 12 0.22% 0.785 3.14 0.25 1.81 99.48% OK
All piping is 12"diameter,designed at slope of 0.22%.All design flows are less than or equal to 1.80 cfs.
PAW Subdivision - Sand and Grease Trap Calculations
9/20/2022
Sand and Grease Traps Must Treat Q50
Number of SG Flow through each Throat Velocity(ft/s)
Combined Q50(cfs) Traps Trapcfs SG Trap Size Baffle Spacing(in) Throat Width(in) <0.50 ft/s Re .
SG Trap W 1.66 1 1.66 1000 Gal 20 48 0.25
SG Trap E 1.80 1 1.80 1000 Gal 20 48 0.27
SG Trap 6 0.93 1 0.93 1000 Gal 20 48 0.14
•. T MATERIALS OTESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY
February 22, 2021
Joe Perdew
Biltmore Company
1580 West Cayuse Creek Drive
Meridian, Idaho 83642
ioe biltmoreco.com
RE: Geotechnical Evaluation
Ustick Linder Subdivision
Meridian, Idaho
ALLWEST Project No. 520-507G
Mr. Perdew:
ALLWEST has completed the geotechnical evaluation for the proposed Ustick Linder
Subdivision to be located at the northwest corner of the West Ustick and North Linder Roads
intersection in Meridian, Idaho. The purpose of this evaluation was to characterize
subsurface soil conditions at the site and provide geotechnical recommendations to assist
design and construction of the proposed development. Based on our evaluation, the site is
suitable for the planned development. The attached report presents the results of our field
evaluation, laboratory testing, and our recommendations.
We appreciate the opportunity to be of service to Biltmore Company. If you have any
questions or need additional information, please contact us at (208) 895-7898.
Sincerely,
ALLWEST
a 14253
W -roi 10�'
Adrian Mascorro, P.E. q� s� Anish Pathak, E.I.
Area Manager Staff Engineer
255 N. Linder Rd., Suite#100, Meridian, ID 83642
Phone: 208.895.7898 • Fax: 208.898.3959
Hayden, ID• Lewiston, ID•Meridian, ID•Spokane Valley,WA•Missoula, MT
www.allwesftesting.com
GEOTECHNICAL EVALUATION
USTICK LINDER SUBDIVISION
MERIDIAN, IDAHO
ALLWEST PROJECT NO. 520-507G
February 22, 2021
Prepared for:
Biltmore Company
1580 W. Cayuse Creek Drive
Meridian, Idaho 83642
Prepared By:
ALLWEST
255 North Linder Road, Suite 100
Meridian, Idaho 83642
A LWE T
WWW.ALLWESTTESTING.COM
TABLE OF CONTENTS
ALLWEST Project No. 520-507G
Ustick Linder Subdivision
Meridian, Idaho
Page
1.0 SCOPE OF SERVICES ........................................................................................2
2.0 PROJECT UNDERSTANDING.............................................................................2
3.0 FIELD EVALUATION PROCEDURES.................................................................3
4.0 SITE CONDITIONS ..............................................................................................3
4.1 General Geologic Conditions............................................................................. 3
4.2 General Soil Conditions..................................................................................... 3
5.0 EXPLORATION AND SAMPLING .......................................................................4
5.1 Subsurface Soil Conditions ...............................................................................4
5.2 Subsurface Water.............................................................................................. 5
6.0 LABORATORY TESTING ....................................................................................5
7.0 CONCLUSIONS AND RECOMMENDATIONS ....................................................5
7.1 Grading and Drainage....................................................................................... 6
7.2 Site Preparation.................................................................................................6
7.3 Subgrade Stabilization ...................................................................................... 7
7.4 Excavation......................................................................................................... 8
7.5 Materials............................................................................................................ 8
7.6 Fill Placement and Compaction......................................................................... 8
7.7 Utility Trenches.................................................................................................. 9
7.8 Wet Weather Construction ................................................................................ 9
7.9 Cold Weather Construction ............................................................................. 10
7.10 Stormwater Disposal ..................................................................................... 10
7.11 Asphalt Pavements ....................................................................................... 11
7.12 Foundation Recommendations...................................................................... 12
7.12.1 Shallow Foundation Design ............................................................... 12
7.12.2 Concrete Slabs-On-Grade ................................................................. 12
8.0 ADDITIONAL RECOMMENDED SERVICES..................................................... 13
9.0 EVALUATION LIMITATIONS............................................................................. 14
Appendix A— Site Vicinity Map, Exploration Location Plan
Appendix B —Test Pit Logs, Unified Soil Classification System
Appendix C— Laboratory Test Results
GEOTECHNICAL I ENVIRONMENTAL
ALLWESTMATERIALS TESTING I SPECIAL INSPECTION
AN EMPLOYEE-OWNED COMPANY
Geotechnical Evaluation
Ustick Linder Subdivision
Meridian, Idaho
ALLWEST has completed the geotechnical evaluation for the proposed Ustick Linder
Subdivision to be located on the northwest corner of the West Ustick and North Linder
Roads intersection in Meridian, Idaho. The general location of the site is shown on
Figure A-1 — Site Vicinity Map in Appendix A of this report. The purpose of this
evaluation was to identify subsurface soil conditions at the site, and provide opinions
and recommendations for the proposed development, relative to earthwork,
stormwater disposal, pavement section design, and foundation construction. This
report details the results of our field evaluation and presents recommendations to
assist design and construction.
1.0 SCOPE OF SERVICES
Our scope of services for the project included the following:
1) Prior to subsurface exploration, we visited the site to observe site accessibility
and to pre-mark exploration locations, as required by Idaho Digline.
2) Notified Idaho Digline to locate on-site utilities, as required by Idaho state law.
3) Subcontracted a backhoe and operator to observe the excavation of 6 test pits
throughout the site.
4) Described, classified, and logged the soils encountered within test pits, and
obtained soil samples within select test pits.
5) Performed seepage tests within select test pits to evaluate subsurface seepage
and installed PVC pipes for future groundwater monitoring.
6) Performed laboratory tests on select soil samples to assess some of the soil
engineering properties and characteristics.
7) Reviewed the results of the field evaluation and laboratory testing, performed
engineering analyses, and prepared this report with our field and laboratory
evaluation results, subsurface logs, and geotechnical-related opinions and
recommendations.
We provided our services for the project in general accordance with our geotechnical
proposal (520-507P) dated December 23, 2020.
2.0 PROJECT UNDERSTANDING
Based on electronic communication with you, and review of the Conceptual Plan for
Ustick Linder Subdivision prepared by Bailey Engineering (dated December 15, 2020),
we understand the project will consist of an approximate 4'/2-acre residential and
commercial development with associated utilities, stormwater disposal facilities, and
GEOTECHNICAL I ENVIRONMENTAL
ALLWESTMATERIALS TESTING I SPECIAL INSPECTION
AN EMPLOYEE-OWNED COMPANY
Geotechnical Evaluation ALLWEST Project No. 520-507G
Ustick Linder Subdivision Page 3
Meridian, Idaho
asphalt-paved roadways and parking. Plans consist of construction of six 4-plex and
three 6-plex buildings with a total of 42 livable units, as well as two commercial
buildings. We did not review final structural plans at the time of this report, but based
on existing developments in the area, we anticipate the proposed buildings will be
single- or two-story structures, constructed utilizing shallow foundations and slab-on-
grade construction. If proposed structures will be taller than two stories, we should be
notified so we can review final structural plans, and provide revised foundation-related
recommendations, as the recommendations in this report are based on maximum
height of two-story structures.
3.0 FIELD EVALUATION PROCEDURES
To complete this evaluation, on January 12, 2021 we observed the excavation of 6 test
pits to a maximum depth of 13'/2 feet. We identified subsurface soil conditions and
logged the subsurface soil profiles, and obtained soil samples for laboratory testing.
We performed field seepage testing within select test pits to help evaluate subsurface
soil seepage. At completion of exploration, the test pits were loosely backfilled with
excavated soil approximately level with existing ground surfaces. Approximate test pit
locations are shown on Figure A-2 — Exploration Location Plan in Appendix A.
4.0 SITE CONDITIONS
At the time of exploration, the site was undeveloped and covered with surficial
vegetation consisting of weeds, bushes, and a tree. The site was bordered by West
Ustick Road to the south, North Linder Road to the east, farmland with a private
residence to the north, and a residential subdivision to the west. The Creason Lateral
borders the site along the southwest corner of the site.
4.1 General Geologic Conditions
The geologic conditions at the site are mapped as gravel of Whitney terrace (Qwg) on
the "Geologic map of the Boise Valley and adjoining area, western Snake River Plain,
Idaho" (by Othberg and Stanford, 1992). Surficial soils consist of 3 to 6 feet of loess
underlain by sandy pebble and cobble gravel down 16 to 80 feet deep.
The soils encountered within test pits are generally consistent with geologic mapping.
4.2 General Soil Conditions
The USDA Natural Resources Conservation Service (NRCS), which represents the
upper 5 feet of soil profile, has mapped the soils on the site as Abo silt loam and Aquic
Torriorthents. The parent materials are mixed alluvium and/or lacustrine deposits
consisting of silt loam, clay loam, loam, fine gravelly coarse sandy loam, sand, and
gravel.
The soils encountered within test pits are generally consistent with NRCS mapping.
GEOTECHNICAL I ENVIRONMENTAL
ALLWESTMATERIALS TESTING I SPECIAL INSPECTION
AN EMPLOYEE-OWNED COMPANY
Geotechnical Evaluation ALLWEST Project No. 520-507G
Ustick Linder Subdivision Page 4
Meridian, Idaho
5.0 EXPLORATION AND SAMPLING
We observed the excavation of the test pits with a CASE 580C rubber-tired backhoe
with a 3-foot-wide bucket. We visually described the soils encountered within test pits
referencing ASTM D 2488, which utilizes the Unified Soil Classification System
(USCS), and we obtained soil samples at select depths for further identification and
laboratory testing. We performed seepage testing within select test pits throughout the
site. The test pit locations were identified on-site with white PVC pipes.
We obtained Google Earth latitude and longitude coordinates of test pit locations with
a hand-held cellular device; these coordinates can be found on individual test pit logs
in the Appendix B, and should be considered accurate to the degree implied by the
method used.
5.1 Subsurface Soil Conditions
At the time of exploration, the site contained approximately 3 inches of surficial roots
and vegetation. We observed a tree in the southwest corner of the site; large tree roots
may be encountered between 2 and 3 feet below ground. In general, the subsurface
soils within the observed test pits consisted of surficial silts with sand or lean clays.
Occasionally, surficial fill soils consisting of sand and gravel were encountered within
the test pits. The subsurface soils underlying the surficial soils generally consisted of
sandy silts overlaying poorly-graded gravel with silt and sand.
Specific descriptions of soils observed throughout our field exploration follow:
Poorly-qraded gravel with sand, Silty sand with gravel (Fill) — At the ground surface
within test pits TP-2 and TP-6, we observed fill soils consisting of poorly-graded gravel
with sand or silty sand with gravel to depths of 1 to 1'/2 feet. We described fill soils as
tan or brown, loose, and moist.
Lean clay with sand, Lean clay (CL)(Native) — Underlying surficial fill in test pit TP-2
and at the ground surface in TP-4, we observed native lean clay down to depths of 2'/2
to 3'/2 feet below ground. We described the clay soils as brown, stiff, and moist.
Silt with sand, Sandy silt (ML) (Native) — At the ground surface in test pits TP-1, TP-3,
and TP-5, or underlying surficial soils in test pits TP-4 and TP-6, we observed native
silt with sand and/or sandy silt down to depths of 3 to 4'/2 feet below ground. We
described the silty soils as brown, medium dense, and moist. We observed moderate
cementation within the sandy silt in test pits TP-3 and TP-5 at approximately 3 to 4 feet
below ground.
Poorly-qraded gravel with silt and sand (GP-GM) — Underlying sandy silt or lean clay
with sand, we observed poorly-graded gravel with silt and sand down to depths of 9 to
13 feet (maximum test pit termination depths). We described poorly-graded gravel with
silt and sand as orange-tan, medium dense, and moist to saturated.
GEOTECHNICAL I ENVIRONMENTAL
ALLWESTMATERIALS TESTING I SPECIAL INSPECTION
AN EMPLOYEE-OWNED COMPANY
Geotechnical Evaluation ALLWEST Project No. 520-507G
Ustick Linder Subdivision Page 5
Meridian, Idaho
Clayey gravel with sand (GC)— Underlying the poorly-graded gravel with silt and sand
within test pit TP-5, we observed clayey gravel with sand down to the test pit
termination depth of 13'/2 feet below ground. We described clayey gravel with sand as
brown, medium dense, and moist.
Detailed soil descriptions, depths, and notes are presented on individual test pit logs
in Appendix B. The descriptive soil terms used on the test pit logs in this report, can be
referenced by the USCS. A copy of the USCS is included in Appendix B.
Subsurface conditions may vary between exploration locations. Such changes in
subsurface conditions may not be apparent until construction, and if they change
significantly from those observed, then accordingly, construction timing, plans, and
costs may change.
5.2 Subsurface Water
At the time of exploration, we encountered groundwater within test pits TP-1 through
TP-4 (in the northern half of the site) at depths between 8 and 9 feet below ground
surface. Groundwater in the area is typically affected by local irrigation and nearby
creeks and laterals, but may also vary due to on-site construction and development to
adjacent sites. Groundwater will fluctuate throughout the different seasons of the year,
but will most likely be affected during seasonal snow melt and irrigation seasons
(March to October).
We installed PVC pipes within each test pit for future groundwater monitoring. Monthly
or biweekly groundwater monitoring should be accomplished throughout snowmelt and
irrigation seasons to verify the presence or absence of groundwater within the on-site
PVC pipes, to assist civil stormwater disposal design.
6.0 LABORATORY TESTING
We performed laboratory testing to supplement field classifications and to assess
some of the soil engineering properties and parameters. The laboratory tests
conducted included moisture content (ASTM D 2216), gradation (ASTM D 1140),
Atterberg limits (ASTM D 4318), and California bearing ratio (CBR) (ASTM D 1883).
Laboratory test results are summarized in Appendix C, and are also presented on test
pit logs in Appendix B.
7.0 CONCLUSIONS AND RECOMMENDATIONS
Based on our observations, testing, and evaluation, in our opinion the site is suitable
for the planned development, provided our recommendations are adhered to. The
following recommendations are presented to assist with design and construction of the
development, relative to earthwork, infrastructure, stormwater disposal, asphalt
pavements, and foundation construction.
GEOTECHNICAL I ENVIRONMENTAL
ALLWESTMATERIALS TESTING I SPECIAL INSPECTION
AN EMPLOYEE-OWNED COMPANY
Geotechnical Evaluation ALLWEST Project No. 520-507G
Ustick Linder Subdivision Page 6
Meridian, Idaho
These recommendations are based on our understanding of the proposed
development, the subsurface conditions observed within the excavated test pits,
laboratory test results, and engineering analysis. If the scope of construction changes,
or if conditions are encountered during construction that differ from those described
herein, we should be notified so we can review our recommendations and provide
revisions, if necessary.
7.1 Grading and Drainage
We did not review final grading plans for this development, but we anticipate site
grading will consist of cuts and fills of up to 2 feet or less. We should be notified if actual
site grading varies significantly from this stated information, as it may affect our
recommendations herein.
Final site grading should be such that surfaces slope away from foundations and any
other development areas.
7.2 Site Preparation
• Prior to conducting site grading, surficial soil containing vegetation, roots and
organics should be removed below proposed site grading fill areas, pavements
or foundation areas, and any other development areas. In general, we anticipate
approximately 3 inches of site stripping will be required for majority of the site to
remove surficial vegetation and roots.
• If the tree encountered in the southwest corner of the site will be removed as
part of the development, or if any large root systems remain in the southern half
of the site (based on old aerial images), those root systems must be completely
over-excavated and replaced with suitable fill soils. Tree roots depths will not
fully be known until construction, but we anticipate a minimum of 2 to 3 feet of
over-excavation will be required to remove large tree root systems.
• Loose test pit backfill will densify with time, which could lead to undesirable
settlements below improved areas. Therefore, if any test pit backfill areas are
located below proposed structures or any improvement areas, test pits should
be re-excavated their entire depth and replaced with suitably moisture-
conditioned and compacted fill. Existing over-excavated soils can be reused to
backfill the test pits, provided the soils are not overly saturated, and they can
achieve the required compaction criteria as required in Section 7.6 Fill
Placement and Compaction. We recommend test pit locations be accurately
surveyed so that they may be located and remediated, prior to earthwork
construction and development.
• After site stripping, any over-excavations, and loose test pit backfill remediation,
the exposed subgrade should be proof-rolled with a minimum of 5-ton vibratory
roller, with a loaded dump truck, or with a loaded front loader, to confirm
subgrade stability. This will assist in identifying soft subgrade areas. If subgrade
GEOTECHNICAL I ENVIRONMENTAL
ALLWESTMATERIALS TESTING I SPECIAL INSPECTION
AN EMPLOYEE-OWNED COMPANY
Geotechnical Evaluation ALLWEST Project No. 520-507G
Ustick Linder Subdivision Page 7
Meridian, Idaho
soil is observed to significantly deflect or pump, it should be over-excavated and
replaced with properly compacted fill or stabilized as recommended in Section
7.3 Subgrade Stabilization.
7.3 Subgrade Stabilization
If the subgrade soils are observed to pump or deflect significantly during grading, the
subgrades should be stabilized prior to fill placement. Subgrades may be stabilized
using geosynthetic reinforcement in conjunction with imported granular structural fill.
The required thicknesses of granular structural fill (used in conjunction with
geosynthetic reinforcement)will be dependent on the construction traffic loading, which
is unknown at this time. Therefore, a certain degree of trial and error may be required
during construction to verify recommended stabilization section thicknesses.
Geosynthetic reinforcement should consist of Tensar TX-160 or equivalent.
Alternatives to Tensar TX-160 must be approved by the geotechnical engineer prior to
use on site. The following recommendations are provided for subgrade stabilization
using geosynthetic reinforcement.
• Geosynthetic reinforcement materials should be placed on a non-disturbed
subgrade with smooth surface. Loose and disturbed soil should be removed
prior to placement of geosynthetic reinforcement materials.
• A minimum weight 4-ounce, non-woven filter fabric should be placed on the
undisturbed subgrade. The geosynthetic reinforcement should be placed
directly on top of the filter fabric. The filter fabric and geosynthetic reinforcement
should be unrolled in the primary direction of fill placement and should be over-
lapped at least 3 feet, or follow manufacturer's recommendations.
• The geosynthetic materials should be pulled taut to remove slack.
• Construction equipment should not be operated directly on the geosynthetic
materials. Fill should be placed from outside the excavation to create a pad to
operate equipment on. We recommend a minimum of 12 to 18 inches of
granular structural fill be placed over the geosynthetic reinforcement before
operating construction equipment on the fill. Low pressure, track-mounted
equipment should be used to place fill over the geosynthetic reinforcement.
• Granular structural fill placed directly over geosynthetic reinforcement should be
properly moisture-conditioned prior to placement, and once placed, be statically
rolled to a firm, non-yielding surface. This section is the "bridge" section over
soft subgrades.
• After the first "bridge" lift has been placed, the remaining fill material above the
"bridge" section should be compacted to structural fill criteria in Section 7.6 Fill
Placement and Compaction, utilizing vibratory compaction methods.
GEOTECHNICAL I ENVIRONMENTAL
ALLWESTMATERIALS TESTING I SPECIAL INSPECTION
AN EMPLOYEE-OWNED COMPANY
Geotechnical Evaluation ALLWEST Project No. 520-507G
Ustick Linder Subdivision Page 8
Meridian, Idaho
• Vibration should be discontinued if it reduces the subgrade stability. If
compaction criterion is not met within the fill lift above the "bridge" section, the
"bridge" section thickness is not enough, and subgrade stabilization must be
attempted again with a greater "bridge" section.
The geotechnical engineer or a representative of the geotechnical engineer must be
on-site during subgrade stabilization to verify our recommendations are followed, and
to provide additional recommendations, as needed.
7.4 Excavation
Excavation of on-site soil can be accomplished with typical excavation equipment. We
recommend excavations greater than 4 feet deep be sloped no steeper than 1.5H:1V
(horizontal to vertical). Alternatively, deeper excavations may be shored or braced in
accordance with Occupational Safety and Health Administration (OSHA) specifications
and local codes. Regarding trench wall support, the site soil is considered Type C soil
according to OSHA guidelines. Ultimately, the contractor is responsible for site safety,
excavation configurations and following OSHA guidelines.
7.5 Materials
Stripped soils and soils containing vegetation or debris are only suitable for use in non-
structural landscape areas. Existing on-site soils may be reused as site grading fill,
provided they are stockpiled separately, they meet the criteria below, and they are
compacted as required in this report. Imported granular soils should be free of
organics, debris and other deleterious material and meet the following criteria. Import
materials should be approved by ALLWEST prior to delivery to the site.
Fill Type Criteria
Site Grading Fill Maximum size <_ 6 inches; 0
Retained on /4 inch sieve < 30o ; Liquid limit < 50/o
Maximum size <_ 6 inches;
Granular Structural Fill, Retained on 3/4-inch sieve < 30%;
Granular Subbase Passing No. 200 sieve <_ 15%; Non-plastic
Alternatively, meet ISPWC section 801 (6 inches
Maximum size <_ 1 inch;
Crushed Base Course Retained on 3/4-inch sieve < 10%;
Passing No. 200 sieve < 10%; Non-plastic
Alternatively, meet ISPWC section 802 (Type I
Maximum size <_ 2 inches;
Utility Trench Backfill Retained on 3/4-inch sieve <030%;
Passing No. 200 sieve <_ 10/o; Non-plastic
Alternatively, meet ISPWC section 305 (Type I
7.6 Fill Placement and Compaction
Fill should be placed in lift thicknesses which are appropriate for the compaction
equipment used. Typically, 8- to 12-inch-thick loose-lifts are appropriate for typical
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rubber-tire and steel-drum compaction equipment. Lift thicknesses should be reduced
to 4 inches for hand-operated compaction equipment. Fill should be moisture-
conditioned to within 2 percentage points of the optimum moisture content prior to
placement to facilitate compaction. Fill should be compacted to the following
percentages of the maximum dry density as determined by ASTM D 1557 (modified
Proctor).
For roadway and utility trench construction only, the local governing jurisdiction may
provide their own method of determining the maximum dry density and compaction
requirements (including subgrade).
Fill Area T (0
Compaction
Sub rade' Proof-rol12
Site Grading Fill / Granular Structural Fill / Pavements 95
Granular Subbase/ Crushed Base Course 952
Utility Trench Backfill 922
'Subgrade stability must be verified and approved by a representative of the geotechnical engineer prior
to any fill placement or construction.
2For roadway and utility trench construction only, the local governing jurisdiction may provide their own
method of determining the maximum dry density and compaction requirements (including subgrade).
7.7 Utility Trenches
Support soils for underground utilities will most likely consist of clays, silts, or gravels
with sand soils. These soils should provide adequate support for utilities, provided
utility subgrades are compacted utilizing vibratory methods, such as with a large
vibratory hoe-pack. If utility pipe subgrades are soft, yielding, and/or saturated at the
time of construction, subgrade over-excavation and replacement with competent
structural fill may be required below utilities. If support soils yield and/or are saturated
at the time of construction, we should be notified to observe these soils and provide
additional recommendations, as necessary.
We strongly recommend backfilling trench excavations with fill soils which meet criteria
in Section 7.5 Materials, as on-site fine-grained soils (silts and clays) may be difficult
to moisture-condition and compact in utility trenches.
7.8 Wet Weather Construction
We recommend earthwork for this site be scheduled for the drier seasons of the year.
If construction is undertaken in wet periods of the year, it will be even more important
to slope the ground surface to provide drainage away from construction. If construction
occurs during or immediately after excessive precipitation, it may be necessary to over-
excavate and replace saturated subgrade soil, which might otherwise be suitable.
The on-site soils are sensitive to disturbance when wet. If these soils become wet and
unstable, we recommend construction traffic is minimized where these soils are
exposed. Low ground-pressure (tracked) equipment should be used to reduce the
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potential for disturbance. Soft and disturbed subgrade areas should be excavated to
undisturbed soil and backfilled with structural fill, compacted to requirements stated in
this report.
In addition, it should be noted the on-site soils tend to have notable adhesion when
wet and may be easily transported off-site by construction traffic.
7.9 Cold Weather Construction
The on-site soils are frost susceptible. If site grading and construction are anticipated
during cold weather, we recommend good winter construction practices be observed.
Snow and ice should be removed from excavated and fill areas prior to additional
earthwork or construction. Pavement and flatwork portions of the construction should
not be placed on frozen ground, nor should the supporting soils be permitted to freeze
during or after construction. Frozen soils must not be used as fill.
If subgrades, or suitably moisture-conditioned and compacted fill lifts, will be left
exposed to freezing temperatures overnight, those areas should be protected with a
minimum of 12 inches of loose soil, or covered with heated construction blankets, so
construction subgrades do not freeze. Any frozen soils should be removed prior to
additional fill placement or construction of any kind.
Earthwork construction during cold inclement weather will require a higher level of
attention and detail to achieve required earthwork construction and compaction criteria
and may lead to additional earthwork requirements and extended construction
schedules.
7.10 Stormwater Disposal
During our field investigation we performed field seepage testing within test pits TP-1,
TP-4, and TP-5, where we noted field-measured seepage rates of 5 to 10 inches per
hour (in/hr) within the poorly-graded gravel with silt and sand.
Due to our field observations and the variability of cemented soils, we do not
recommend stormwater disposal occur within or above sandy silt, as cemented soils
will exhibit very poor and inconsistent soil seepage.
Based on our field evaluation, the following recommended seepage rate, with an
appropriate factor of safety, should be utilized for on-site stormwater disposal into
poorly-graded gravel with silt and sand.
• Poorly-graded gravel with silt and sand ........................... 4 in/hr
Stormwater disposal facilities should be constructed a minimum of 1 foot into the gravel
with silt and sand layer. Seepage beds should be "burrito wrapped" or otherwise
maintain a separation/filter fabric between native fine-grained soils and drain rock/filter
sand to help prevent fine-soil migration into drainable/filtering media. During
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construction, ALLWEST should observe stormwater disposal facility subgrades to
establish if the suitable receiving soil is encountered and to ensure the separation/filter
fabric has been properly installed.
The proper separation from bottom of stormwater disposal facilities and seasonal high
groundwater should be maintained. At the time of exploration, we observed
groundwater in test pits TP-1 through TP-4 at depths ranging from approximately 8 and
9 feet below existing ground surfaces.
We installed slotted PVC pipes within each test pit for future groundwater monitoring.
At a minimum, these pipes should be monitored monthly or biweekly during seasonal
snow melt and irrigation seasons (March to October) to confirm the seasonal high
groundwater elevations throughout the site.
7.11 Asphalt Pavements
Prior to pavement section construction, the pavement subgrade should be proof-rolled
as recommended in Section 7.2 Site Preparation (or as recommended by local
jurisdictions). Local and collector roadways should be designed for a 20-year
Equivalent Single Axle Load (ESAL) of 33,000 and 370,000, respectively, which are
equivalent to traffic indexes (TI) of 6 and 8, respectively. If actual traffic conditions are
different than what is stated, we should be notified so that we may modify our pavement
section design.
We anticipate the roadway subgrades will consist of silt and/or clay soils. As such, we
performed CBR testing on a lean clay with sand soil to assist pavement section design.
Based on laboratory testing, we obtained a CBR of 10 for the lean clay with sand,
which correlates to an R-value of 25.
The following flexible asphalt pavement section design is provided adhering to the
Idaho Transportation Department (ITD), which utilizes the AASHTO pavement design
methodology. Based on subgrade preparation requirements, design assumptions, and
frost-depth considerations, we recommend the following pavement sections be utilized
for parking and access lanes, and subdivision roadway construction for local and
collector roadways.
Asphalt Crushed Granular
Pavement Application Concrete Base Course Subbase
inches inches inches
Local Roadway / Parking /Access Lanes 2.5 4 9
Collector Roadway 3 6 11
Base course and subbase should conform to the material recommendations as noted
in this report and should be placed over a properly prepared subgrade. The subgrade,
subbase, and base course surfaces should slope at no less than 2% away from the
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crown of the roadway to help reduce the potential for surface water infiltration into the
underlying pavement subgrade.
Asphalt concrete pavement should be compacted to minimum of 92% of the Rice
density. Crack maintenance on pavements should be performed at a minimum of every
3 years, or when cracking is evident. Crack sealing will help reduce surface water
infiltration into the supporting soils.
7.12 Foundation Recommendations
The following recommendations should be utilized to design and construct proposed
foundations.
7.12.1 Shallow Foundation Design
• For frost protection, footings should be embedded at least 24 inches below the
lowest adjacent grade.
• Spread footings should be supported entirely on a minimum of 1 foot of granular
structural fill over existing native subgrades. Granular structural fill should
extend a minimum of 6 inches beyond sides of footings.
• Prior to placing concrete, ALLWEST should observe all footing excavations to
verify that our recommendations are being followed. Foundation subgrade soil
should be probed and approved, prior to placement of fill or concrete.
• Footings may be designed for the following bearing pressures:
Allowable Bearing Minimum Granular
Subgrade Type Pressure Structural Fill Thickness
(psfl below Footing
feet
Native Silt/ Clay 2,500 1 1
The net allowable bearing pressure value may be increased by 1/3 to account for
transient loads such as wind and seismic.
• If the previous recommendations are implemented, it is our opinion total
settlement will be approximately less than 1 inch and differential settlement will
be approximately less than '/2 of an inch.
• A coefficient of friction of 0.45 may be used for sliding resistance between
concrete footings and imported granular structural fill.
7.12.2 Concrete Slabs-On-Grade
We recommend placing a minimum of 6 inches of crushed base course immediately
below slabs and flatwork. Subgrade within these areas should be prepared as
GEOTECHNICAL I ENVIRONMENTAL
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Meridian, Idaho
indicated in Section 7.2 Site Preparation of this report. Base course should be
compacted as recommended in Section 7.5 Fill Placement and Compaction.
We recommend consideration be given to including a moisture vapor retarder beneath
concrete slab-on-grade floors to retard moisture migration through the slabs if
moisture-sensitive floor coverings are planned. We recommend the moisture retarder
be installed per American Concrete Institute (ACI) recommendations and
specifications. To protect slabs from moisture migration which may impact flooring
performance, it is important to include the moisture vapor retarder as well as directing
surface and subsurface water away from the slabs. In addition, concrete should have
adequate time to cure prior to placing impermeable flooring.
8.0 ADDITIONAL RECOMMENDED SERVICES
To maintain continuity and efficiency, we recommend ALLWEST be retained to provide
observations and testing throughout construction. As an independent testing company,
ALLWEST can document the recommendations included in this report are properly
implemented, provide quality control testing, and observe earthwork for conformance
to project specifications. As a minimum, we recommend the following testing and
observations be provided by ALLWEST:
• Observe site stripping, any over-excavations, and compaction of test pit backfill,
and any other soil backfills.
• Observe proof-rolling of the subgrade prior to fill placement.
• Observe removal of disturbed soil and subgrade stabilization, if required.
• Observe seepage bed subgrades and observe overall construction.
• Observe, probe, and approved foundation subgrade soils prior to granular
structural fill placement and compaction.
• Conduct compaction testing of fill placed for general site grading, utilities,
pavement areas, and foundation areas.
• Observe placement of and test asphalt for compaction, oil content, and
gradation.
If we are not retained to provide the recommended construction observation and
testing services, we shall not be responsible for soil engineering-related construction
errors or omissions.
GEOTECHNICAL I ENVIRONMENTAL
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Geotechnical Evaluation ALLWEST Project No. 520-507G
Ustick Linder Subdivision Page 14
Meridian, Idaho
9.0 EVALUATION LIMITATIONS
This report has been prepared to assist design and construction of the proposed Ustick
Linder Subdivision in Meridian, Idaho. Our services consist of professional opinions
and conclusions made in accordance with generally accepted geotechnical
engineering principles and practices in our local area at the time this report was
prepared. This acknowledgement is in lieu of all warranties either expressed or implied.
The following plates complete this report:
Appendix A— Site Vicinity Map, Exploration Location Plan
Appendix B — Test Pit Logs, Unified Soil Classification System
Appendix C — Laboratory Test Results
GEOTECHNICAL I ENVIRONMENTAL
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Appendix A
A-1 — Site Vicinity Map
A-2 — Exploration Location Plan
ALLWEST
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Figure A-1 - Site Vicinity Map
ALLWEST Geotechnical Evaluation
Ustick Linder Subdivision
Meridian, Idaho
255 N. Linder Road, Suite 100 Client- Biltmore Company
Meridian, Idaho 83642 Project No.: 520-507G
Phone- (208) 895-7898 Fax- (208) 898-3959 1 Date- February 2021
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0 Approximate location of test pit observed by ALLWEST.
Slotted PVC pipe installed in test pit.
Figure A-2 - Exploration Location Plan
Geotechnical Evaluation
ALLWEST
Ustick Linder Subdivision
Meridian, Idaho
255 N. Linder Road, Suite 100 Client: Biltmore Company
Meridian, Idaho 83642 Project No.: 520-507G
Phone: (208) 895-7898 Fax: (208) 898-3959 Date: February 2021
Appendix B
Test Pit Logs
Unified Soil Classification System (USCS)
ALLWEST
ALLWEST DATE STARTED: 1/12/2021 TP - 1
DATE FINISHED: 1/12/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
EXCAVATION METHOD:3-ft wide bucket
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc.
LOGGER:Anish Pathak
TEST PIT LOG WEATHER:Cloudy
PROJECT:520-507G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Ustick Linder Subdivision
LATITUDE(DEGREES):N 43°38'8.3868"(43.635663°)
= LONGITUDE(DEGREES):W-116°24'54.216" (-116.41506°) W
H U U a
o- j TOTAL DEPTH:9' Q
0CL
DESCRIPTION W `o NOTES
SILT with sand(Native);brown,medium dense, moist Significant roots and vegetation observed to 3
inches.
1
ML
2
3 Sandy SILT; brown, medium dense, moist
ML
4 Poorly-graded GRAVEL with silt and sand;orange-tan, medium
dense,moist to saturated
0
5 o Field seepage test performed at 5 feet.
o Field seepage rate=5 in/hr.
0
6 0
GP-GM
0
O
7
0
O
8 — o
O
0
9 Test pit terminated at 9 feet.
Slotted PVC pipe installed to 9 feet.
1
1
1
1
1
WATER LEVELS
8' a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 1/12/2021 TP - 2
DATE FINISHED: 1/12/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
EXCAVATION METHOD:3-ft wide bucket
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc.
LOGGER:Anish Pathak
TEST PIT LOG WEATHER:Cloudy
PROJECT:520-507G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Ustick Linder Subdivision
LATITUDE(DEGREES):N 43°38'8.2428"(43.635623°)
= LONGITUDE(DEGREES):W-116°24'50.3388" (-116.413983°) W
H U U a
o- j TOTAL DEPTH:9.5' Q
0CL
DESCRIPTION W `o NOTES
Poorly-graded GRAVEL with sand(Fill);tan, loose, moist
FILL
1 Lean CLAY with sand(Native);brown,stiff, moist
Passing No.200 sieve=82%
00(
BK ILL=38, PL= 19,PI= 19
CBR=10.0
00(
CL
3
Poorly-graded GRAVEL with silt and sand;orange-tan, medium
dense,moist to saturated °
4 0
0
O
5
0
O
6 0
GP-GM
0
7
O
0
O
o
O
9
0
Test pit terminated at 9-1/2 feet.
Slotted PVC pipe installed to 9-1/2 feet.
1
1
1
1
1
WATER LEVELS
8.5' a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 1/12/2021 TP - 3
DATE FINISHED: 1/12/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
EXCAVATION METHOD:3-ft wide bucket
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc.
LOGGER:Anish Pathak
TEST PIT LOG WEATHER:Cloudy
PROJECT:520-507G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Ustick Linder Subdivision
LATITUDE(DEGREES):N 43°38'5.6544"(43.634904°)
= LONGITUDE(DEGREES):W-116°24'53.8776" (-116.414966°) W
H U U a
o- j TOTAL DEPTH: 12' Q
0CL
DESCRIPTION W `o NOTES
SILT with sand(Native);brown,medium dense, moist Significant roots and vegetation observed to 3
inches.
1 ML
2 Sandy SILT; brown, medium dense, moist
3 ML ... moderate cementation observed from 3 to 3-1/2 feet
4 Poorly-graded GRAVEL with silt and sand;orange-tan, medium
dense,moist to saturated
0
5 0
0
0
6 0
0
O
7
0
O
GP-GM o
O
9 - o
0
1 O
0
O
1 0
0
1 Test pit terminated at 12 feet.
Slotted PVC pipe installed to 12 feet.
1
1
WATER LEVELS
9' EZ WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 1/12/2021 TP - 4
DATE FINISHED: 1/12/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
EXCAVATION METHOD:3-ft wide bucket
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc.
LOGGER:Anish Pathak
TEST PIT LOG WEATHER:Cloudy
PROJECT:520-507G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Ustick Linder Subdivision
LATITUDE(DEGREES):N 43°38'5.6868"(43.634913°)
= LONGITUDE(DEGREES):W-116°24'50.364" (-116.41399°) W
H U U a
o- j TOTAL DEPTH: 10' Q
0CL
DESCRIPTION W `o NOTES
Lean CLAY(Native); brown,stiff, moist
BG Passing No.200 sieve=89%
Moisture content=23%
1 CL LL=38, PL= 19,PI= 19
2
Sandy SILT; brown, medium dense, moist BG Passing No.200 sieve=57%
Moisture content=29%
3
ML
4 Poorly-graded GRAVEL with silt and sand;orange-tan, medium
dense,moist to saturated
0
5 0
0
0
6 o Field seepage test performed at 6 feet.
Field seepage rate=8 in/hr.
0
7 GP-GM
0
O
8 o
O
9 SZ
0
0
10— Test pit terminated at 10 feet.
Slotted PVC pipe installed to 10 feet.
1
1
1
1
WATER LEVELS
9' EZ WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 1/12/2021 TP - 5
DATE FINISHED: 1/12/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
EXCAVATION METHOD:3-ft wide bucket
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc.
LOGGER:Anish Pathak
TEST PIT LOG WEATHER:Cloudy
PROJECT:520-507G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Ustick Linder Subdivision
LATITUDE(DEGREES):N 43°38'3.0156"(43.634171°)
= LONGITUDE(DEGREES):W-116°24'53.4276" (-116.414841°) Lu
H U U a
o- j TOTAL DEPTH: 13.5' Q
0CL
DESCRIPTION W `� NOTES
SILT with sand(Native);brown,medium dense, moist Significant roots and vegetation observed to 3
inches.
1 ML BG Passing No.200 sieve=73%
Moisture content=20%
2
Sandy SILT; brown, medium dense, moist
3 BG Passing No.200 sieve=51%
ML Moisture content=22%
... moderate cementation observed from 3-1/2 to 4 feet
4—
Poorly-graded GRAVEL with silt and sand;orange-tan, medium
dense,moist
5 0
0
0
g Field seepage test performed at 6 feet.
o Field seepage rate= 10 in/hr.
0
7 0
GP-GM
O
0
O
0
O
9
0
0
1 Clayey GRAVEL with sand;brown,medium dense, moist
1
GC
1
F/o
Test pit terminated at 13-1/2 feet.
Slotted PVC pipe installed to 13-1/2 feet.
1
WATER LEVELS
a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 1/12/2021 TP - 6
DATE FINISHED: 1/12/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
EXCAVATION METHOD:3-ft wide bucket
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc.
LOGGER:Anish Pathak
TEST PIT LOG WEATHER:Cloudy
PROJECT:520-507G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Ustick Linder Subdivision
LATITUDE(DEGREES):N 43°38'2.8248"(43.634118°)
= LONGITUDE(DEGREES):W-116°24'51.0444" (-116.414179°) W
H U U a
o- j TOTAL DEPTH: 13' Q
0CL
DESCRIPTION W `o NOTES
Silty SAND with gravel(Fill); brown,loose, moist <XXSignificant roots and vegetation observed to 3
inches.
00(
FILL00(
1 00(
Sandy SILT(Native); brown, medium dense, moist
2
ML
3 Poorly-graded GRAVEL with silt and sand;orange-tan, medium
dense,moist
DU
4 0
0
0
5 O
DU
0
0
6
DU
0
7 0
0
DU
GP-GM
DU
0
g o
0
0
1
0
0
1
0
0
1 0
0
0
1 Test pit terminated at 13 feet.
Slotted PVC pipe installed to 13 feet.
1
WATER LEVELS
a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
Unified Soil Classification System
MAJOR DIVISIONS SYMBOL TYPICAL NAMES
Well-Graded Gravel,
CLEAN GW Gravel-Sand Mixtures.
GRAVELS GP Poorly-Graded Gravel,
GRAVELS Gravel-Sand Mixtures.
Silty Gravel,
COARSE GRAVELS GM Gravel-Sand-Silt Mixtures.
GRAINED WITH FINES GC Clayey Gravel,
SOILS Gravel-Sand-Clay Mixtures.
Well-Graded Sand,
CLEAN SW Gravelly Sand.
SANDS SP Poorly-Graded Sand,
SANDS Gravelly Sand.
Silty Sand,
SANDS L SM Sand-Silt Mixtures.
WITH FINES Sc Clayey Sand,
Sand-Clay Mixtures.
ML Inorganic Silt,
SILTS AND CLAYS Silty or Clayey Fine Sand.
Inorganic Clay of Low to
LIQUID LIMIT CL Medium Plasticity,
LESS THAN 50% Sandy or Silty Clay.
FINE OL Organic Silt and Clay of Low
GRAINED Plasticity.
SOILS Inorganic Silt, Elastic Silt,
SILTS AND CLAYS MH Micaceous Silt,
Fine Sand or Silt.
LIQUID LIMIT CH Inorganic Clay of High Plasticity,
GREATER THAN 50% Fat Clay.
OH Organic Clay of Medium to High
Plasticity.
Highly Organic Soils PT Peat, Muck and Other Highly
Organic Soils.
ALLWEST
Appendix C
Laboratory Test Results
ALLWEST
Summary of Laboratory Test Results
Moisture Gradation Atterberg Limits
Test Pit Depth Content Liquid Plasticity CBR Sample Classification
No. (Feet) M Gravel Sand Silt/Clay Limit Index (USCS)
M M M M M
2 1 -2 - 18 82 38 19 10 Lean CLAY with sand CL
4 0.5- 1 23 11 89 38 19 Lean CLAY CL
4 2.5- 3 29 43 57 Sandy SILT ML
5 1 - 1.5 20 27 73 SILT with sand ML
5 3 - 3.5 22 49 51 Sandy SILT ML
Table C-1
255 N. Linder Road, Suite 100 • Meridian, Idaho 83642 • (208) 895-7895 • Fax (208) 898-3959
www.allwesttesting.com
This report may not be reproduced, except in full, without the permission of ALLWEST.
LIQUID AND PLASTIC LIMITS TEST REPORT
60
Dashed line indicates the approximate
upper limit boundary for natural soils
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J
Q 10
0 ;
c
L-ML ML or OL MH or OH
0
0 10 20 30 40 50 60 70 80 90 100 110
LIQUID LIMIT
0 MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
• Lean Clay with sand 38 19 19 82% CL
c■ Lean Clay 38 19 19 89% CL
CD
U
X
U
U
U
7
O
` Project No. 520-507G Client: Biltmore Company Remarks:
aD Project: Ustick Linder Subdivision
c *Location: TP-2 Depth: F-2'
■Location: TP-4 Depth: 0.5'-l'
0
cn
D ALLWEST
Figure C-1
Tested By: C. Downes Checked By:J.Varozza
California Bearing Ratio
ASTM D 1883
Project: Ustick Linder Subdivision Project No.: 520-507G
Client: Biltmore Company Location: TP-2 @ 1 - 2 ft
Date Tested: 2/1/21 Compaction Method: ASTM D1557
Tested By: C. Downes Classification: Lean Clay with sand (CL)
275
250
225
200
175
Q.
400 150
a
o 125
a
n 100
PSI @ 0.1 inch penetration= 100
75
50
25
0
0 0.1 0.2 0.3 0.4 0.5
Penetration(inches)
CBR @ 0.1 Inch Penetration: 10.0 Maximum Dry Unit Weight(pcf): 113.8
Swell (%): 2.8 Optimum Water Content (%): 12.6
Dry Unit Weight Before Soak(pcf): 103.4 Remold of Max. Dry Unt Wgt (%): 91
Water Content Before Soak(%): 13.6
Water Content After Soak, Top 1 Inch (%): 26.4
Surcharge (psf): 50
Immersion Period (hrs): 96
Reviewed By: James Varozza
Figure: C-2
ALLWESY
255 N Linder Rd,Suite 100•Meridian,ID 83642•(208)895-7898•Fax(208)898-3959
www.allwesttesting.com
This report shall not be reproduced except in full without the permission of ALLWEST.
Test Pit: TP-1 TP-2 TP-3 TP-4 TP-5 TP-6
Existing Ground 2568.6 2569.7 2568.6 NA 2569.5 2570.1
Elevation (ft):
Feet Below Ground Surface
Date
7/29/2022** 2.8 4.0 4.7 6.3 8.3
GW Elevation (ft.) 2565.8 2565.7 2563.9 NA 2563.2 2561.8
8/11/2022 5.6 6.1 5.2 * 6.5 8.4
GW Elevation (ft.) 2563.0 2563.6 2563.4 NA 2563.0 2561.7
8/30/2022 5.0 5.9 6.1 * 6.4 8.3
GW Elevation (ft.) 2563.6 2563.8 2562.5 NA 2563.1 2561.8
9/9/2022 5.2 5.8 5.0 * 6.3 8.2
GW Elevation (ft.) 2563.4 2563.9 2563.6 NA 2563.2 2561.9
Notes: *Piezometer destroyed
**Adjacent field to the north was being irrigated
Table 1
ALLWEST Groundwater Monitoring
Pavilion at Windsong
Meridian, Idaho
255 N. Linder Road, Suite 100 Client Name: Biltmore Company
Meridian, Idaho 83642 Project No.: 520-507G
Phone: 208-895-7898 Fax: 208-898-3959 Date: September 2022