HomeMy WebLinkAboutStudies Applicant 10/7/2024
www.branchengineering.com Page | 1
September 30, 2024
Ryan Walla
Arbor South Architecture, PC
Via email: ryanwalla@arborsouth.com
RE: INFILTRATION TESTING RESULTS
THURSTON LIFE CENTER
5842 MAIN STREET
SPRINGFIELD, OREGON
BRANCH ENGINEERING, INC PROJECT NO. 24-192
INTRODUCTION
Branch Engineering Inc (BEI) staff visited the above referenced site on September 6, 2024 to set up
falling head infiltration tests at three locations as shown on the attached Figure-1 Infiltration Test
Location Map. A rubber tracked mini-excavator was used to advance excavations to approximately 30-
to 42-inches below ground surface (BGS). A hand auger was used in the bottom of the excavations to
advance a 6-inch diameter hole into the soil profile. 6-inch diameter PVC pipes were then embedded
and encased in the holes, with the excavations backfilled.
We previously visited the site on June 20, 2024 to perform a geotechnical investigation using a 25-ton
Cone Penetrometer Test (CPT) truck. Our findings and recommendations for construction are
presented in a report dated July 2, 2024.
On September 9, 2024, the infiltration test locations were pre-saturated and testing was performed on
September 10, 2024. The infiltration testing was performed to determine rates to be used in design by
others. The results presented herein are for initial design and should be verified by the design engineer
of record (EOR) at the time of construction. The following is a summary of our visit to the site and
testing results.
SITE SOILS
The site soils observed in the test pits consisted of stiff light brown clay with silt. At Infiltration Test
2 (IT-2), dense gravels were observed throughout the soil profile mixed with light brown clay and silt,
at IT-3, trace fine grain sand contend was observed in the clayey silt at 42-inches BGS. The fine grain
alluvium on the site is underlain by rounded gravel deposits. The CPT tests were met with refusal on
gravel deposits at depths ranging from approximately 6- to 9-feet BGS.
The NRCS Web Soil Survey of the Lane County Area has also been included with this report and maps
the site soil unit as Coburg-Urban land complex, which is described as moderately well drained
alluvium.
GROUNDWATER
We did not encounter any groundwater during our on-site explorations. A well log from a car wash
facility adjacent to the site lists static groundwater at 14-feet BGS and is attached for reference. The
presence of groundwater is not expected to impact infiltration facility design.
Thurston Life Center – Infiltration Testing
BEI Project Number: 24-192
Branch Engineering, Inc. Page | 2
INFILTRATION TESTING
Site infiltration testing was conducted on September 10, 2024 in accordance with the 2014 City of
Eugene Stormwater Management Manual. The soil is assumed to be laterally homogeneous and that
sidewall infiltration is negligible as a 6-inch diameter, open-ended, plastic standpipe was used for
containment of the water column. Water was added to the pipe to pre-saturate the soil the day prior
to testing. Infiltration testing commenced over three successive trials with water being added and the
height of the water column being recorded over time. The measured infiltration rate is shown below
in Table 1 (no factor of safety applied) with the field data presented in the attached Infiltration Test
Results page.
Table 1: Infiltration Test Results
Test ID Soil Description Test Depth (inches) Infiltration Rate (in/hr)
IT-1 Clay with Silt (CL/ML) 38 10
IT-2 Gravel with Clay (ML-GP) 47 13
IT-3 Clay with trace sand (CL-SC) 52 9
CONCLUSIONS
No factor of safety has been applied to the results; we recommend a minimum factor of safety of 2
for design. The values above are specific to the soil at the test locations and should not be used for
other soil types. This rate should be considered preliminary and should be confirmed by the EOR once
the stormwater facility has been completed as soil type and consistency may vary with distance from
the test location.
The site appears to be served by a public stormwater system, overflow outlets from infiltration
facilities to the stormwater system are recommended to be included in the facility design. Any area(s)
proposed for infiltration shall not be subjected to compaction of the soil by vehicle traffic, storage of
materials, or other means that can influence the rate of infiltration in those areas. The required setback
from property lines and structures is 5-feet and 10-feet, respectively. It is the client/design
professional’s responsibility to determine that the stormwater facility meets these requirements.
LIMITATIONS
This report has been prepared for the exclusive use of the addressee and their designated
representatives for use in design of the proposed development. The analysis and recommendations
contained herein were prepared in general accordance with the standards of practice for the area at
the time of this report’s preparation, and may not be suitable for purposes other than those described
in this report.
Subsurface explorations indicate soil conditions at specific locations and depths and do not
necessarily reflect soil and groundwater variations that may exist between other locations at the site.
If design changes are made that may affect the results of our testing, or a substantial amount of time
passes between our investigation and the site development, we reserve the right to review the changes
for applicability.
We assume no responsibility or liability for engineering, inspection, or testing performed by others
and no warranty, expressed or implied, is given. Use of this report constitutes an agreement and
consent by the addressee and their designated representatives to the limitations listed above.
Thurston Life Center – Infiltration Testing
BEI Project Number: 24-192
Branch Engineering, Inc. Page | 3
If you have any questions regarding the test method, data analysis or design, please contact the
undersigned.
Sincerely,
Branch Engineering Inc,
Matthew Renner P.E.
Construction Engineer
ATTACHED:
Figure-1 Infiltration Test Location Map
Infiltration Field Data
ORWD Well Log
NRCS Soils Map
310 5th STREET, SPRINGFIELD, OREGON 97477SITE INFILTRATION TESTING MAP - THURSTON LIFE FOUNDATIONFIGURE-109-10-2024PROJECT NO. 24-192SUBJECT SITESCALE: 1:40 (11x17)LEGENDNOTE: SITE ASSESSMENT DRAWING BY THE FAVREAU GROUP, 2024INDICATES APPROXIMATELOCATION OFINFILTRATION TESTIT-15842 MAIN STREET SPRINGFIELD, OREGONIT-1IT-3IT-2
Infiltration Test Results
Project: Thurston Life Center
Testing Date: 9/10/2024
BEI Project Number: 24-192
Test Type: Encased Falling Head Infiltration
Time = 0 at addition of H2O
Infiltration Test 1 Trial 1
Elapsed
Time (min)
Depth to Water
Surface (in)
Depth of Water
(in)
Rate of Fall
(in/min)
Rate of Fall
(in/hr)Avg Rate of Fall T-1 (in/hr)
Standpipe Diameter (in) 6 0 35.0 17.0
Standpipe Height AGS (in) 14 10 40.5 11.5 0.55 33.0
Pipe length (in) 52 17 43.5 8.5 0.43 25.7
Volume of Water Added (gal) 2 28 45.5 6.5 0.18 10.9
Clocktime at Start 10:00 31 47.0 5.0 0.50 30.0
ASTM Soil Type (CL/ML) 39 48.5 3.5 0.19 11.3
Test Depth (in) 38 45 49.5 2.5 0.17 10.0
53 50.5 1.5 0.13 7.5 15.9
Infiltration Test 1 Trial 2
Elapsed
Time (min)
Depth to Water
Surface (in)
Depth of Water
(in)
Rate of Fall
(in/min)
Rate of Fall
(in/hr) Avg Rate of Fall T-2 (in/hr)
Volume of Water Added (gal) 2 0 34.0 18.0
Clocktime 10:54 12 40.0 12.0 0.50 30.0
21 43.0 9.0 0.33 20.0
30 45.0 7.0 0.22 13.3
43 48.0 4.0 0.23 13.8
49 49.0 3.0 0.17 10.0
58 50.0 2.0 0.11 6.7 12.8
Infiltration Test 1 Trial 3
Elapsed
Time (min)
Depth to Water
Surface (in)
Depth of Water
(in)
Rate of Fall
(in/min)
Rate of Fall
(in/hr) Avg Rate of Fall T-3 (in/hr)
Volume of Water Added (gal) 2 0 31.5 20.5
Clocktime 11:55 8 36.5 15.5 0.63 37.5
14 39.0 13.0 0.42 25.0
23 41.0 11.0 0.22 13.3
33 43.0 9.0 0.20 12.0
44 44.5 7.5 0.14 8.2
52 45.5 6.5 0.13 7.5
60 46.5 5.5 0.13 7.5
77 48 4.0 0.09 5.3
87 48.5 3.5 0.05 3.0
10.2
Note: First measurement removed from average rate calculation Measured Rate (in/hr)
10.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
22.0
0 10 20 30 40 50 60 70 80 90 100Depth of Water (in)Time (min)
Rate of Water Level Fall (in/min)
Trial 1
Trial 2
Trial 3
Infiltration Test Results
Project: Thurston Life Center
Testing Date: 9/10/2024
BEI Project Number: 24-192
Test Type: Encased Falling Head Infiltration
Time = 0 at addition of H2O
Infiltration Test 2 Trial 1
Elapsed
Time (min)
Depth to Water
Surface (in)
Depth of Water
(in)
Rate of Fall
(in/min)
Rate of Fall
(in/hr) Avg Rate of Fall T-1 (in/hr)
Standpipe Diameter (in) 6 0 46.0 13.0
Standpipe Height AGS (in) 12 11 54.0 5.0 0.73 43.6
Pipe Length (in) 59 18 55.5 3.5 0.21 12.9
Volume of Water Added (gal) 2 25 57.0 2.0 0.21 12.9
Clocktime 9:56 32 59.0 0.0 0.29 17.1 14.3
ASTM Soil Type (ML-GP)
Test Depth BGS (in) 47
Infiltration Test 2 Trial 2
Elapsed
Time (min)
Depth to Water
Surface (in)
Depth of Water
(in)
Rate of Fall
(in/min)
Rate of Fall
(in/hr) AVG Rate of Fall T-2 (in/hr)
Volume of Water Added (gal) 2 0 41.0 18.0
Clocktime 11:17 4 45.5 13.5 1.13 67.5
7 48.5 10.5 1.00 60.0
14 51.5 7.5 0.43 25.7
23 53.5 5.5 0.22 13.3
27 54.0 5.0 0.13 7.5
37 55.0 4.0 0.10 6.0
46 56.0 3.0 0.11 6.7
52 56.5 2.5 0.08 5.0 17.7
Infiltration Test 2 Trial 3
Elapsed
Time (min)
Depth to Water
Surface (in)
Depth of Water
(in)
Rate of Fall
(in/min)
Rate of Fall
(in/hr)AVG Rate of Fall T-2 (in/hr)
Volume of Water Added (gal) 2 0 36.0 23.0
Clocktime 12:07 8 46.5 12.5 1.31 78.8
18 51.5 7.5 0.50 30.0
29 54.0 5.0 0.23 13.6
37 54.5 4.5 0.06 3.8
47 55.5 3.5 0.10 6.0 13.3
Note: First measurement removed from average rate calculation Reccomended Rate (in/hr)
13.0
2.0
7.0
12.0
17.0
22.0
27.0
0 5 10 15 20 25 30 35 40 45 50Depth of Water (in)Time (min)
Rate of Water Fall (in/min)
Trial 1
Trial 2
Trial 3
Infiltration Test Results
Project: Thurston Life Center
Testing Date: 9/10/2024
BEI Project Number: 24-192
Test Type: Encased Falling Head Infiltration
Time = 0 at addition of H2O
Infiltration Test 3 Trial 1
Elapsed
Time (min)
Depth to Water
Surface (in)
Depth of Water
(in)
Rate of Fall
(in/min)
Rate of Fall
(in/hr)Avg Rate of Fall T-1 (in/hr)
Standpipe Diameter (in) 6 0 46.0 14.0
Standpipe Height AGS (in) 8 7 48.5 11.5 0.36 21.4
Pipe length (in) 60 14 50.5 9.5 0.29 17.1
Volume of Water Added (gal) 2 21 52.0 8.0 0.21 12.9
Clocktime at Start 10:05 28 53.0 7.0 0.14 8.6
ASTM Soil Type (CL) 36 54 6.0 0.13 7.5
Test Depth (in) 52 45 55.5 4.5 0.17 10.0
54 56.5 3.5 0.11 6.7 10.5
Infiltration Test 3 Trial 2
Elapsed
Time (min)
Depth to Water
Surface (in)
Depth of Water
(in)
Rate of Fall
(in/min)
Rate of Fall
(in/hr) Avg Rate of Fall T-2 (in/hr)
Volume of Water Added (gal) 2 0 44.0 16.0
Clocktime 11:00 7 46.5 13.5 0.36 21.4
16 48.5 11.5 0.22 13.3
25 50.0 10.0 0.17 10.0
39 52.0 8.0 0.14 8.6
48 53.5 6.5 0.17 10.0
56 54.3 5.7 0.10 6.0 9.6
Infiltration Test 3 Trial 3
Elapsed
Time (min)
Depth to Water
Surface (in)
Depth of Water
(in)
Rate of Fall
(in/min)
Rate of Fall
(in/hr) Avg Rate of Fall T-3 (in/hr)
Volume of Water Added (gal) 2 0 38.5 21.5
Clocktime 12:00 9 42.5 17.5 0.44 26.7
19 45.5 14.5 0.30 18.0
26 46.8 13.2 0.19 11.1
38 48.5 11.5 0.14 8.5
46 49.8 10.2 0.16 9.7
53 51.0 9.0 0.17 10.3
73 53.5 6.5 0.13 7.5
85 54.0 6.0 0.04 2.5 9.7
Note: First measurement removed from average rate calculation Measured Rate (in/hr)
9.0
2.0
7.0
12.0
17.0
22.0
27.0
0 10 20 30 40 50 60 70 80 90Depth of Water (in)Time (min)
Rate of Water Level Fall (in/min)
Trial 1
Trial 2
Trial 3
LANE 71079
LANE 71079
Soil Map—Lane County Area, Oregon
(5842 Main St. Springfield)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/1/2024
Page 1 of 348768304876910487699048770704877150487723048773104876830487691048769904877070487715048772304877310505570505650505730505810505890505970506050506130506210506290506370
505570 505650 505730 505810 505890 505970 506050 506130 506210 506290 506370
44° 2' 56'' N 122° 55' 50'' W44° 2' 56'' N122° 55' 13'' W44° 2' 39'' N
122° 55' 50'' W44° 2' 39'' N
122° 55' 13'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84
0 150 300 600 900
Feet
0 50 100 200 300
Meters
Map Scale: 1:3,760 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:20,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Lane County Area, Oregon
Survey Area Data: Version 22, Sep 8, 2023
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jun 12, 2019—Jun
19, 2019
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Soil Map—Lane County Area, Oregon
(5842 Main St. Springfield)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/1/2024
Page 2 of 3
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
32 Coburg-Urban land complex 49.1 78.9%
101 Oxley-Urban land complex 0.2 0.2%
119 Salem-Urban land complex 12.3 19.7%
2224A Courtney gravelly silty clay
loam, 0 to 3 percent slopes
0.7 1.2%
Totals for Area of Interest 62.3 100.0%
Soil Map—Lane County Area, Oregon 5842 Main St. Springfield
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/1/2024
Page 3 of 3
Lane County Area, Oregon
32—Coburg-Urban land complex
Map Unit Setting
National map unit symbol: 2369
Elevation: 100 to 1,300 feet
Mean annual precipitation: 30 to 60 inches
Mean annual air temperature: 50 to 55 degrees F
Frost-free period: 160 to 235 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Coburg and similar soils:55 percent
Urban land:30 percent
Minor components:4 percent
Estimates are based on observations, descriptions, and transects of
the mapunit.
Description of Coburg
Setting
Landform:Stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Loamy alluvium over clayey alluvium
Typical profile
H1 - 0 to 18 inches: silty clay loam
H2 - 18 to 53 inches: silty clay
H3 - 53 to 65 inches: fine sandy loam
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Moderately well drained
Capacity of the most limiting layer to transmit water
(Ksat):Moderately high (0.20 to 0.57 in/hr)
Depth to water table:About 18 to 30 inches
Frequency of flooding:None
Frequency of ponding:None
Available water supply, 0 to 60 inches: High (about 11.0 inches)
Interpretive groups
Land capability classification (irrigated): 2w
Land capability classification (nonirrigated): 2w
Hydrologic Soil Group: C
Ecological site: R002XC006OR - Stream Terrace Group
Forage suitability group: Moderately Well Drained < 15% Slopes
(G002XY004OR)
Map Unit Description: Coburg-Urban land complex---Lane County Area, Oregon 5842 Main St. Springfield
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/1/2024
Page 1 of 2
Other vegetative classification: Moderately Well Drained < 15%
Slopes (G002XY004OR)
Hydric soil rating: No
Description of Urban Land
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 8
Hydric soil rating: No
Minor Components
Conser
Percent of map unit:4 percent
Landform:Stream terraces
Hydric soil rating: Yes
Data Source Information
Soil Survey Area: Lane County Area, Oregon
Survey Area Data: Version 22, Sep 8, 2023
Map Unit Description: Coburg-Urban land complex---Lane County Area, Oregon 5842 Main St. Springfield
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/1/2024
Page 2 of 2
