HomeMy WebLinkAboutJasper Slough Viewpoint Geotechnical - signed
p: 503.779.2577 | www.branchengineering.com
January 29, 2024
Mr. Simon Daws
Willamalane Park and Recreation District
Via Email: simond@willamalane.org
RE: GEOTECHNICAL FOUNDATION INVESTIGATION
JASPER SLOUGH WILDLIFE VIEWPOINT
JASPER ROAD
SPRINGFIELD, OREGON BRANCH ENGINEERING INC. PROJECT NO. 23-589
Pursuant to your authorization, Branch Engineering Inc. (BEI) performed a limited geotechnical
engineering investigation at the subject site located at the above listed address. This report is intended
fulfill the requirements in Section 1803 of the 2022 Oregon Structural Specialty Code (OSSC, 2022)
and presents the results of our site research, field exploration and testing, data analyses, as well as
our conclusions and recommended geotechnical design parameters for the project.
We appreciate the opportunity to be of service to you. Please contact the undersigned if you have
questions or concerns regarding this report.
Sincerely,
Branch Engineering Inc.
Ronald J. Derrick, P.E., G.E. Matthew Renner, P.E.
Principal Geotechnical Engineer Construction Engineer
Geotechnical Investigation – Jasper Slough Viewpoint
Jasper Road Springfield, OR
Project Number: 23-589
Branch Engineering, Inc.
TABLE OF CONTENTS
1.0 INTRODUCTION ....................................................................................................................................1
1.1 Purpose and Scope of Work 1
1.2 Project Location and Description 1
1.3 Site information Resources 1
2.0 GEOLOGIC SETTING .............................................................................................................................1
2.1 Regional Geology 2
2.2 Site Geology 2
3.0 SITE SUBSURFACE CONDITIONS ......................................................................................................2
3.1 Subsurface Soils 2
3.2 Laboratory Testing 3
3.2 Groundwater 3
4.0 GEOLOGIC HAZARDS ...........................................................................................................................4
5.0 CONCLUSIONS .......................................................................................................................................5
6.0 DESIGN RECOMMENDATIONS ...........................................................................................................5
6.1 Foundation Subgrade Preparation Recommendations 5
6.2 Bearing Capacity 6
6.3 Settlement 6
6.4 Friction Coefficient and Lateral Earth Pressures 6
6.5 Structural Fill 6
6.6 Seismic Design Parameters 7
6.7 Concrete Slab-on-Grade and Pathway Extensions 7
7.0 CONSTRUCTION CONSIDERATIONS ...............................................................................................7
7.1 Wet Weather/Dry Weather Construction Practices 7
7.2 Excavations 8
7.3 Slopes 8
7.4 Site Drainage 8
7.5 Expansive Soil Mitigation Strategies 8
7.6 Geotechnical Construction Site Observations 8
8.0 REPORT LIMITATIONS ........................................................................................................................9
FIGURE 1 – Site Vicinity Map
FIGURE 2 – Exploration Map
FIGURE 3 – Geologic Mapping
APPENDIX A –USCS Soils Key, Exploratory Test Pit Logs
APPENDIX B – Recommended Earthwork Specifications
Geotechnical Investigation – Jasper Slough Viewpoint
Jasper Road Springfield, OR
Project Number: 23-589
Branch Engineering, Inc. Page | 1
1.0 INTRODUCTION
1.1 Purpose and Scope of Work
The purpose of this work is to establish and present geotechnical engineering criteria and
requirements related to the site and subsurface conditions that may influence the design and
construction of the proposed project. Our scope of work included a field reconnaissance with a
subsurface investigation performed by BEI personnel, an engineering data review of existing geologic
and geotechnical reports, and other pertinent site research activities that culminated in the
preparation of this report.
1.2 Project Location and Description
The project site is located at the approximate coordinates of 44.035078° North Latitude and
122.980649° West Longitude, in Springfield, Oregon (see Figure-1 Vicinity Map), adjacent to the Mill
Race Multi-use Path. For the purposes of this report, and investigation the site consists of the area
between a slough of the Middle Fork of the Willamette River, and the multi-use path. The ground
surface is grass covered with recently planted trees. The site topography slopes gently downhill from
the multi-use path, then steepens as it drops to the slough, in which standing water was present during
our visit.
Our understanding of the proposed work, is that a platform will be constructed to overlook the slough,
with walkways connecting to the Mill Race Path. The platform will be constructed by a wood frame
structure supported on posts bearing on footings located on the sloping ground between the pathway
and slough.
1.3 Site information Resources
The following site investigation activities were performed and literature resources were reviewed for
pertinent site information:
Google Earth Professional, earth.google.com
Lane County Zone and Plan Maps
https://lcmaps.lanecounty.org/LaneCountyMaps/ZoneAndPlanMapsApp/index.html
Two (2) hand tool excavations advanced by BEI staff on 1/10/2024, with hand auger boring
advanced in the base of the excavations as conditions allowed.
Two (2) Dynamic Cone Penetrometer (DCP) Tests to a maximum depth of approximately 7.5-
feet below ground surface (BGS).
Oregon Department of Geology and Mineral Industries (DOGAMI) web hazard viewer.
Review of the DOGAMI Digital Map of the Southern Willamette Valley Benton, Lane, Linn,
Marion, and Polk Counties, Oregon, McClaughry, Wiley, Ferns, and Madin, O-10-03, 2010.
United Stated Department of Agriculture (USDA), Natural Resources Conservation Services
(NRCS) Web Soil Survey of Lane County Area, Oregon
Oregon Structural Specialty Code 2022 (OSSC 2022), applicable building code criteria
2.0 GEOLOGIC SETTING
The following sections describe the regional and local site geology:
Geotechnical Investigation – Jasper Slough Viewpoint
Jasper Road Springfield, OR
Project Number: 23-589
Branch Engineering, Inc. Page | 2
2.1 Regional Geology
The subject site lies within the southern portion of the Willamette Valley, east of the Coast Range and
west of the Cascade Mountains Provinces. In Oregon, the Willamette Valley is an elongate basin which
narrows at both ends before terminating in the Calapooya Divide to the south and the Columbia River
to the north. The basin is approximately 130 miles long and 40 miles wide. The valley is drained by
the Willamette River and drops from an elevation of approximately 400-feet at Eugene, to near sea
level at the northern end of the basin where the Willamette River drains into the Columbia River.
The Willamette River Valley in the area of the subject site is believed to be heavily influenced by
historic hydrology, including the movement and sediment deposition of the McKenzie, Middle, and
Coast Forks of the Willamette Rivers. The Willamette River once occupied the wetland areas of west
Eugene and frequently overflowed onto the low-lying floodplains. During the last deglaciation and the
resulting termination of the Last Glacial Maximum in North America, the Willamette Valley was
cyclically flooded by catastrophic breaks in the ice dams of Glacial Lake Missoula. Occurring several
times over an approximately 2,000-year period between 13,000 to 15,000 ago, these flood events filled
the valley to an elevation of 350- to 400-feet before retreating, causing sequences of upward fining
deposits of silt and clay that may or may not still be present in areas depending on erosion by
subsequent fluvial actions. Much of these deposits have since become developed and urbanized.
2.2 Site Geology
The DOGAMI Geology of the Southern Willamette Valley OFR O-10-03 (shown in Figure-3) maps the
geologic unit underlying the site as Older Alluvium dated to the Holocene and described as
unconsolidated deposits of gravel, sand, silt, and clay that formed on low terraces, above more recent
alluvial deposits, on high river benches along major streams and abandoned stream channels that
post-date the withdrawal of the last Missoula Flood.
3.0 SITE SUBSURFACE CONDITIONS
The analyses, conclusions, and recommendations contained in this report are based on site conditions
as they presently exist and assume that the results from the subsurface explorations presented in
Appendix A are representative of the subsurface conditions throughout the site. If, during
construction the subsurface conditions differ from those encountered in the site explorations, BEI
requests that we be informed to review the site conditions and adjust our recommendations, if
necessary.
3.1 Subsurface Soils
BEI personnel performed hand tool excavation work to expose the soil profile in the upper,
approximate 24-inches then used a combination of DCP testing and hand auger to advance
explorations to approximately 7.5-feet BGS at the locations shown on the attached Figure-2 Site
Exploration Map.
DCP testing consists of recording blow counts required to drive a graduated steel probe through 10
cm sections. A 35-lb free falling weight is dropped 18-inches to drive the probe. The field data is
entered into software to correlate Standard Penetration Testing (N’) values and classify the consistency
of the soil.
Geotechnical Investigation – Jasper Slough Viewpoint
Jasper Road Springfield, OR
Project Number: 23-589
Branch Engineering, Inc. Page | 3
The results of our exploration activities are summarized below:
Previously placed fill was observed in both explorations to depths of 20- to 24-inches. The fill
consists of rounded gravel and cobbles, with organic soil and minor concrete and asphalt
debris. The presence of the fill material is expected as it was encountered in the construction
of the adjacent subdivision to the east as observed by BEI, and during the construction of the
Mill Race Path as reported to BEI by Willamalane staff.
Alluvial silt, clay, and sand were observed to underlie the fill. The fine grain soil is medium
stiff in consistency near the surface then becomes soft, or loose with depth, at approximately
3-feet BGS. Fine grain sand content increases with depth.
Gravels were found underlying the fine grain soil at approximately 7.5-feet BGS where refusal
to the DCP probe and hand auger was encountered.
The NRCS web soil survey maps one soil unit present across the area of the proposed platform,
Chapman loam, which is described as well drained alluvium from mixed sources. See attached soil
mapping and complete description. The NRCS soil mapping and description is consistent with our site
observations.
3.2 Laboratory Testing
Representative soil samples were collected at the site for laboratory testing. In-house results from in-
situ moisture contents (ASTM D2216) and Free Swell (IS-2720) tests are presented below in Table 1.
The shrink/swell potential of the near surface soil is considered moderate to. The recommendations
presented in the Foundation Preparation and Expansive Soil Mitigation sections of the report below
are intended to mitigate the effects of the shrink/swell potential of the subgrade soil.
Table 1: Laboratory testing results
Location Depth BGS
(inches)) Soil Description Moisture
content Free Swell Swell Rating
TP-2 44 Light brown
clayey SILT (MH) 39% 40% Moderate
TP-2 66 Light brown SILT
(ML) 40% 35% Moderate
3.2 Groundwater
Static groundwater was encountered near the elevation of the gravels at 7.5-feet BGS, and rose to
approximately 6.5-feet BGS after completion of the hand augers. The underlying gravels are highly
permeable, and the level of the static groundwater may correspond to the level of the water in the
adjacent slough.
We expect that groundwater levels (from the regional water table or perched lenses) will fluctuate with
the seasons and should be expected to be highest during the late winter and spring months when
rainstorms are more intense and frequent, and soils are near saturation. The presence of groundwater
is not expected to impact shallow foundations if they are founded within 5-feet of the current ground
Geotechnical Investigation – Jasper Slough Viewpoint
Jasper Road Springfield, OR
Project Number: 23-589
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surface elevation, however, dewatering may be required for construction during the wet season if
perched lenses of water are encountered in excavations. Excavations below 6-feet BGS and into the
underlying gravels are likely to encounter groundwater. If the water level in the adjacent slough drops
during the dry season, the groundwater elevation at the project location is expected to decrease.
4.0 GEOLOGIC HAZARDS
OSSC 2022 (1803.5.11) required criteria for hazards the geotechnical investigation shall address for
seismic site class designations C through F are listed below. The DOGAMI online Statewide Geohazards
Viewer was used for mapping references.
Slope Instability: The site is not mapped as being at risk for land sliding. The potential for
landslides to occur onsite is unlikely due to the relatively flat topography on-site and
surrounding terrain. The DOGAMI online hazard viewer maps the area surrounding the site as
low risk for landslide susceptibility.
Liquefaction: Liquefaction is caused by a rapid increase in pore water pressure within a
saturated soil that reduces the interparticle friction between soil grains that can lead to the
sudden loss of shear strength within the soil. This can cause a loss of bearing capacity,
densification of subsurface soils that can lead to large surficial settlements, and the migration
of soil particles to the surface in the form of sand boils. Loose, granular sands with a low fine-
grained soil content and a recent depositional history are especially vulnerable to liquefaction.
Saturation is required for a soil to experience liquefaction.
The DOGAMI online hazard viewer maps the site as being at a high risk for liquefaction. The
soil profile observed in the zone saturated by groundwater (6- to 7.5-feet BGS) is consistent
with a soil susceptible to liquefaction. However, the zone of wet soil is relatively thin, and the
underlying gravels are dense, and not susceptible to liquefaction. If settlement under
foundations due to liquefaction is a concern, we recommend that the foundation loads be
transferred to the underlying gravel deposits.
Expected Earthquake Shaking: The site is mapped within a zone of strong shaking that would
typically be associated with very large earthquakes generated from the Cascadia Subduction
Zone off the Oregon coastline.
Surface Displacement Due to Faulting or Seismically Induced Lateral Spreading or Lateral Flow:
There are no known faults on the site that could cause large surficial displacements. The site
soil, and the bank next to the slough have a low to moderate risk of lateral spread during a
seismic event due to the soft consistency of the material, and steepening slope adjacent to the
slough.
Tsunami/seiche: No major bodies of water capable of generating a Tsunami are near to the
site. The site is bordered by a slough holding water, but this body of water is not capable of
generating a seiche. Therefore, the risk of a tsunami or seiche to affect the site is none.
Total and Differential Settlement: See Section 6.3 below for a discussion of settlement risk.
Settlement will be governed by the loads placed on the bearing soil and the type of soil.
Geotechnical Investigation – Jasper Slough Viewpoint
Jasper Road Springfield, OR
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Expansive Soils: The silt and sand soil overlying the gravels are characterized by a moderate
shrink/swell potential and not considered to be highly expansive.
Flood Risk: The site is mapped within the 100-year flood plain.
5.0 CONCLUSIONS
Based on our field observations, subsurface explorations, and data analyses, our investigation did not
reveal any specific site features or subsurface conditions that would impede the project as proposed
and the development can proceed as planned provided that the recommendations contained within
this report are incorporated into the design and construction of the project.
6.0 DESIGN RECOMMENDATIONS
The following sections present site-specific recommendations for site preparation. Earthwork shall be
performed in general accordance with the standard of practice as generally described by Appendix J
of the International Building Code (IBC), the 2022 Oregon Structural Specialty Code (OSSC), and as
specified in this report. General material and construction specifications for the items discussed
herein are provided in Appendix B.
The subsurface conditions observed in our site investigation represent specific locations on the site.
Should soft or unsuitable soils extend to a depth or extent greater than that described herein, or areas
of distinct soil variation be discovered, this office shall be notified to perform site observations and
additional excavation may be required.
6.1 Foundation Subgrade Preparation Recommendations
Based on drawings provided to BEI, the platform structure will be supported by posts. The previously
placed fill material on the site is undocumented, contains at least a fraction of unsuitable material,
and varies in consistency. We do not recommend using the fill material to support structures.
The native, fine-grain soil underlying the fill is soft to medium-stiff in consistency, bearing capacities
and lateral earth pressures for the fine grain soil are provided in Sections 6.2 and 6.4 of this report.
The fine grain soil is susceptible to settlement unless consolidated by compaction with mechanical
equipment. For placement of foundation loads on the fine-grain soil we recommend the following:
Expose native subgrade material free of organics, or previously placed fill, expected depth is
approximately 2.5- to 3-feet BGS.
If moisture conditions allow, mechanically consolidate the subgrade material with a reversible
plate compactor, vibratory plate mounted to an excavator, smooth drum roller, or other
suitable method.
Place a minimum of 12-inches of compacted aggregate thickness on subgrade soil in
accordance with recommendations in Section 6.5 below. The compacted aggregate shall extend
a minimum of 12-inches horizontally beyond the edge of footings, or a distance equivalent to
the fill thickness, whichever is greater.
Geotechnical Investigation – Jasper Slough Viewpoint
Jasper Road Springfield, OR
Project Number: 23-589
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The gravel deposits underlying the fine grain soil and fill material are dense and capable of supporting
foundation loads with less risk of settlement than the overlying fine grain soil. For a structure using
posts to support framework for the proposed platform we recommend transferring foundation loads
to bear on the gravels at approximately 7.5-feet BGS. Using an auger mounted to trucks or construction
equipment could be an efficient method to set posts or concrete forms bearing on the gravels.
6.2 Bearing Capacity
Following the foundation preparation described above, for footings bearing on the fine grain soil, a
bearing capacity of 1,500 psf may be used for design.
For foundation loads bearing on the gravel deposits a bearing capacity of 3,000 psf may be used.
These allowable bearing capacities may be increased by 1/3 for short term loading, such as wind or
seismic events.
6.3 Settlement
Following the foundation preparation described above, the estimated total and differential settlement
for new shallow foundations after project completion is not expected to exceed 1.5-inches and 3/4-
inch over a 20-foot span between equivalently loaded footings, respectively.
For foundations, or posts bearing on the underlying gravels the total and differential settlement is not
expected to exceed 1-inch.
6.4 Friction Coefficient and Lateral Earth Pressures
For use in design, the following parameters are given based on an internal angle of friction of 20° for
the native soil encountered below the previously placed fill on the site and above the gravel deposits.
These values assume that there are no hydrostatic pressures and retained soil is not inclined. If these
assumptions change during the course of the project, our office should be notified so we can
reevaluate our recommendations.
1. The coefficient of friction for concrete poured neat against undisturbed native soil is 0.35 and
if poured atop a minimum thickness of 12-inches of compacted aggregate placed on the on-
site material the coefficient is 0.45.
2. The passive earth pressure is 200 pcf.
3. The active earth pressure is 50 pcf for unrestrained walls and the at rest earth pressure for a
restrained wall is 70 pcf.
6.5 Structural Fill
All engineered fill placed on the site shall consist of homogenous material and shall meet the following
recommendations.
The recommended compaction level for crushed aggregate in structural areas and beneath
pavements is 90 percent of the maximum dry density as determined by ASTM D-1557
(modified Proctor).
Geotechnical Investigation – Jasper Slough Viewpoint
Jasper Road Springfield, OR
Project Number: 23-589
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Utility trenches located outside the building area in pavement and load bearing areas should
be backfilled with approved material and compacted to at least 90% of the maximum dry
density.
Prior to placement on-site, the aggregate or alternative fill material to be used shall be
approved by the GER. If no recent Proctor curve (moisture-density relationship) is available
for the material, a material sample will be required for testing to determine the maximum dry
density and optimum moisture content of the aggregate or fill material.
Compaction shall be measured by on site testing with a nuclear densometer (ASTM D-6938),
or sand cone method (ASTM D-1556) on structural fill with thicknesses in excess of 12-inches.
If compaction testing is not feasible for any onsite or imported material due to factors such
as oversize rock content or variable material, proof rolls with a fully loaded 10 cubic yard
haul-truck or equivalent equipment shall be observed at regular intervals. Any observed areas
of excessive yielding or rutting will require removal and replacement with granular fill or
moisture conditioning and re-compaction. Compaction should be assessed at two-foot
vertical intervals during fill placement.
Structural fill shall be moisture conditioned to within +/- 2% of optimum moisture content
and compacted in lifts with loose thicknesses not exceeding 8-inches. Periodic visits to the
site to verify lift thickness, source material, and compaction effort shall be conducted by the
GER, or designated representative, and documented.
6.6 Seismic Design Parameters
Based on the soil properties encountered in our explorations and from nearby well logs, we
recommend a Seismic Site Class C, very dense soil and soft rock (Table 20.3-1 ASCE 7-16) for the design
of site structures.
6.7 Concrete Slab-on-Grade and Pathway Extensions
For extensions of the existing multi-use path, or concrete slab-on-grade transitions to the proposed
platform, we recommend the following preparation. The undocumented fill material shall be removed
from asphalt concrete (AC) pavement, or concrete slab areas. Compacted aggregate with a minimum
thickness of 8-inches shall be placed on native subgrade soil. Areas of soft subgrade soil, or previously
placed fill shall be improved by either removal, or compaction of the subgrade material in-place. The
compacted aggregate should be placed in conformance with the recommendations in Section 6.5. For
improvement of existing subgrade material, the subgrade should be compacted to an unyielding state
prior to the placement of compacted aggregate.
7.0 CONSTRUCTION CONSIDERATIONS
7.1 Wet Weather/Dry Weather Construction Practices
The near surface fine-grained soils, if left exposed to prolonged precipitation, will become saturated
and soften. Subgrade soil below foundations, slabs, and pavements shall be covered with compacted
aggregate in a timely manner after excavation to minimize moisture fluctuations. BEI recommends
Geotechnical Investigation – Jasper Slough Viewpoint
Jasper Road Springfield, OR
Project Number: 23-589
Branch Engineering, Inc. Page | 8
that foundation subgrade preparation and general site earthwork be performed during the dry
season—generally June through October.
Construction during the wet season may require special drainage considerations, such as covering of
excavations, pumping to mitigate standing water in footing excavations, or over-excavation of
moisture softened soils. Construction traffic should not be allowed to drive directly on exposed
subgrades. Construction traffic routes will also be more susceptible to “pumping” and rutting during
the wet season and will likely require thicker rock sections.
7.2 Excavations
Conventional excavation equipment in proper working order should be capable of making the
excavations necessary for the site improvements. The site soils are typically classified as OSHA Type
C soils due to the variable nature of the soil profile in the upper 5-feet. The loose consistency of the
near-surface fill may cause sloughing of gravel. Excavations should be performed in accordance with
the applicable safety guidelines outlined by OSHA and the state.
7.3 Slopes
Temporary slopes cut into native soil should not be graded steeper than 1:1 and permanent slopes
(fill or cut) should not exceed a gradient of 2:1 unless specifically evaluated for stability.
7.4 Site Drainage
Alteration of existing grades for this project will likely change drainage patterns that should not
adversely affect adjacent properties. Perimeter landscape and hardscape grades shall be sloped away
from foundations and water shall not be allowed to pond adjacent to footings during or after
construction.
7.5 Expansive Soil Mitigation Strategies
Site soils were observed to be moderately expansive. Although the risk to on-site structures is low, we
recommend the following precautions be adhered to during and after construction to help minimize
the risk:
Subgrade soils should not be allowed to dry out and should be covered with crushed rock in a
timely manner to prevent moisture changes. Soils can be periodically wetted to maintain their
insitu moisture content if excavation takes place during the drier months.
Install roof gutters immediately after roof construction—unless during the dry season—and
tightline them to a suitable disposal location.
Sources of water should be prevented from saturating subgrades or becoming trapped below
pavement surfaces and drainage structures should also not be located adjacent to pavement
or other hardscapes.
7.6 Geotechnical Construction Site Observations
Periodic site observations by a geotechnical representative of BEI are recommended during the
construction of the project; the specific phases of construction that should be observed are shown in
the following table.
Table 2:
Geotechnical Investigation – Jasper Slough Viewpoint
Jasper Road Springfield, OR
Project Number: 23-589
Branch Engineering, Inc. Page | 9
Recommended Construction Phases to be Observed by the Geotechnical Engineer
At completion of subgrade excavation
Subgrade observation by the geotechnical
engineer before aggregate and geogrid (if
applicable) placement.
Imported fill material Observation of material or information on
material type and source.
Placement or Compaction of fill material Observation by geotechnical engineer or test
results by qualified testing agency.
8.0 REPORT LIMITATIONS
This report has presented BEI’s site observations and research, subsurface explorations, geotechnical
engineering analyses, and recommendations for the proposed site development. The conclusions in
this report are based on the conditions described in this report and are intended for the exclusive use
of the addressee and their designated representatives for use in design and construction of the
development described herein. The analysis and recommendations may not be suitable for other
structures or purposes.
Services performed by the geotechnical engineer for this project have been conducted with the level
of care and skill exercised by other current geotechnical professionals in this area. No warranty is
herein expressed or implied. The conclusions in this report are based on the site conditions as they
currently exist and it is assumed that the limited site locations that were physically investigated
generally represent the subsurface conditions at the site. This report represents our findings and
should site development or site conditions change, or if a substantial amount of time goes by between
our site investigation and site development, we reserve the right to review this report for its
applicability and adjust our recommendations. If you have any questions regarding the contents of
this report, please contact our office.
JASPER ROAD SPRINGFIELD, OREGONSITE VICINITY MAP - JASPER SLOUGH WILDLIFE VIEWPOINTSCALE: N.T.S.FIGURE-101-10-2024PROJECT NO. 23-589SITE LOCATONNOTE: MAP SOURCE LANE COUNTY GIS SERVICES, 2024
JASPER ROAD SPRINGFIELD, OREGON
SITE EXPLORATION MAP - JASPER SLOUGH WILDLIFE VIEWPOINT
SCALE: 1:30 (8.5 x 11)
FIGURE-2
12-13-2023
PROJECT NO. 23-589
LEGEND:TP-1
NOTE: SITE PLAN BY WILLAMALANE PARK AND RECREATION DISTRICT, 2023
INDICATES APPROXIMATE LOCATION OF
HAND TOOL EXCAVATION, HAND AUGER
AND DCP TEST
TP-1
TP-2
SCALE: NOT TO SCALE
FIGURE-3
01-10-2024
PROJECT NO. 23-589
APPROX. SITE
LOCATION
NOTE: GEOLOGIC MAP SOURCE: OPEN-FILE-REPORT O-10-03 DIGITAL GEOLOGIC MAP OF THE SOUTHERN
WILLAMETTE VALLEY, BENTON, LANE, LINN, MARION, AND POLK COUNTIES, BY DOGAMI, 2010
SITE GEOLOGIC MAPPING - JASPER SLOUGH VIEWPOINT
JASPER ROAD, SPRINGFIELD, OREGON
APPENDIXAPPENDIXAPPENDIXAPPENDIX AAAA
TTTTeeeesssstttt PPPPiiiitttt LLLLoooogggg SSSSuuuummmmmmmmaaaarrrriiiieeeessss aaaannnndddd NNNNRRRRCCCCSSSS SSSSooooiiiillll
SSSSuuuurrrrvvvveeeeyyyy
Depth1
2
3
4
5
6
7
8
9
10
11
12
13
14
15 GraphicMaterial Description
Fill: Loose to medium dense, gravels and cobbles with organic soil, gravels
are rounded, cobbles up to 5" diameter, with concrete debris and minor sand SamplePocket Pen. (tsf)Free SwellMoisture Content: ⊗PL and LL: ⬤━∎
Borehole ID: TP-1
Sheet 1 of 1
Client:Willamalane Project Name:Willamalane Mill Race Path Obs. Platform
Project Number:23-589 Project Location:Mill Race Path at Jasper Trailhead
Date Started:Jan 10 2024 Completed:Jan 10 2023 Logged By:MWR Checked By:RJD
Drilling Contractor:Branch Engineering Inc.Latitude:44.035078 Longitude:-122.980649 Elevation:
Drilling Method:Test Pit Excavation Ground Water Levels
Equipment:Hand Auger/DCP
Hammer Type:35 lb Slide Hammer
Notes:
10 20 30 40 50 60 70 80 90
Refusal to hand equipment and auger on gravel
See attached DCP test log
WILDCAT DYNAMIC CONE LOG
PROJECT NUMBER: 23-589
DATE STARTED: 01-10-2024
DATE COMPLETED: 01-10-2024
HOLE #: DCP-1
CREW: MWR SURFACE ELEVATION: N/A
PROJECT: Mill Race Observation Platform WATER ON COMPLETION:Yes
ADDRESS: Jasper Road Trailhead HAMMER WEIGHT: 35 lbs.
LOCATION: Springfield, Oregon CONE AREA: 10 sq. cm
BLOWS RESISTANCE GRAPH OF CONE RESISTANCE TESTED CONSISTENCY
DEPTH PER 10 cm Kg/cm² 0 50 100 150 N' NON-COHESIVE COHESIVE
-
-
- 1 ft
-
- 9 40.0 ••••••••••• 11 MEDIUM DENSE STIFF
- 2 ft 8 35.5 •••••••••• 10 LOOSE STIFF
- 8 35.5 •••••••••• 10 LOOSE STIFF
- 6 26.6 ••••••• 7 LOOSE MEDIUM STIFF
- 3 ft 5 22.2 •••••• 6 LOOSE MEDIUM STIFF
- 1 m 3 13.3 ••• 3 VERY LOOSE SOFT
- 4 15.4 •••• 4 VERY LOOSE SOFT
- 4 ft 4 15.4 •••• 4 VERY LOOSE SOFT
- 6 23.2 •••••• 6 LOOSE MEDIUM STIFF
- 5 19.3 ••••• 5 LOOSE MEDIUM STIFF
- 5 ft 5 19.3 ••••• 5 LOOSE MEDIUM STIFF
- 3 11.6 ••• 3 VERY LOOSE SOFT
- 4 15.4 •••• 4 VERY LOOSE SOFT
- 6 ft 2 7.7 •• 2 VERY LOOSE SOFT
- 2 7.7 •• 2 VERY LOOSE SOFT
- 2 m 2 7.7 •• 2 VERY LOOSE SOFT
- 7 ft 3 10.3 •• 2 VERY LOOSE SOFT
- 10 34.2 ••••••••• 9 LOOSE STIFF
- 25 85.5 •••••••••••••••••••••••• 24 MEDIUM DENSE VERY STIFF
- 8 ft
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- 9 ft
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- 3 m 10 ft
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- 11 ft
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C:\My Documents\Wildcat\WC_XL97.XLS
Depth1
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Fill: Loose to medium dense, gravels and cobbles with organic soil, gravels
are rounded, cobbles up to 5" diameter, with concrete, asphalt debris and
minor sand
Medium stiff, brown clayey SILT (ML), moist, trace fine sand, becomes soft
with depth
Soft, gray-brown clayey SILT (ML-SM) with fine sand, red staining, becomes
wet at 6.5-feet SampleS-1
BAG
S-2
BAG Pocket Pen. (tsf)Free SwellMoisture Content: ⊗PL and LL: ⬤━∎
Borehole ID: TP-2
Sheet 1 of 1
Client:Willamalane Project Name:Willamalane Mill Race Path Obs. Platform
Project Number:23-589 Project Location:Mill Race Path at Jasper Trailhead
Date Started:Jan 10 2024 Completed:Jan 10 2024 Logged By:MWR Checked By:RJD
Drilling Contractor:Branch Engineering Inc.Latitude:44.035078 Longitude:-122.980649 Elevation:
Drilling Method:Hand Auger Ground Water Levels
Equipment:Hand Auger/DCP
Hammer Type:35 lb Slide Hammer After drilling 6.50 on Jan 10 2024
Notes:
10 20 30 40 50 60 70 80 90
See attached DCP test log
WILDCAT DYNAMIC CONE LOG
PROJECT NUMBER: 23-589
DATE STARTED: 01-10-2024
DATE COMPLETED: 01-10-2024
HOLE #: DCP-2
CREW: MWR SURFACE ELEVATION: N/A
PROJECT: Mill Race Observation Platform WATER ON COMPLETION:Yes
ADDRESS: Jasper Road Trailhead HAMMER WEIGHT: 35 lbs.
LOCATION: Springfield, Oregon CONE AREA: 10 sq. cm
BLOWS RESISTANCE GRAPH OF CONE RESISTANCE TESTED CONSISTENCY
DEPTH PER 10 cm Kg/cm² 0 50 100 150 N' NON-COHESIVE COHESIVE
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- 1 ft
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- 2 ft 7 31.1 ••••••••• 8 LOOSE MEDIUM STIFF
- 5 22.2 •••••• 6 LOOSE MEDIUM STIFF
- 6 26.6 ••••••• 7 LOOSE MEDIUM STIFF
- 3 ft 5 22.2 •••••• 6 LOOSE MEDIUM STIFF
- 1 m 6 26.6 ••••••• 7 LOOSE MEDIUM STIFF
- 7 27.0 ••••••• 7 LOOSE MEDIUM STIFF
- 4 ft 7 27.0 ••••••• 7 LOOSE MEDIUM STIFF
- 5 19.3 ••••• 5 LOOSE MEDIUM STIFF
- 5 19.3 ••••• 5 LOOSE MEDIUM STIFF
- 5 ft 4 15.4 •••• 4 VERY LOOSE SOFT
- 2 7.7 •• 2 VERY LOOSE SOFT
- 4 15.4 •••• 4 VERY LOOSE SOFT
- 6 ft 3 11.6 ••• 3 VERY LOOSE SOFT
- 3 11.6 ••• 3 VERY LOOSE SOFT
- 2 m 14 54.0 ••••••••••••••• 15 MEDIUM DENSE STIFF
- 7 ft 22 75.2 ••••••••••••••••••••• 21 MEDIUM DENSE VERY STIFF
- 25 85.5 •••••••••••••••••••••••• 24 MEDIUM DENSE VERY STIFF
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- 8 ft
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- 3 m 10 ft
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- 11 ft
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- 4 m 13 ft
C:\My Documents\Wildcat\WC_XL97.XLS
Soil Map—Lane County Area, Oregon
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
1/24/2024
Page 1 of 34875650487568048757104875740487577048758004875830487586048758904875920487595048756504875680487571048757404875770487580048758304875860487589048759204875950501450501480501510501540501570501600501630501660
501450 501480 501510 501540 501570 501600 501630 501660
44° 2' 12'' N 122° 58' 55'' W44° 2' 12'' N122° 58' 44'' W44° 2' 2'' N
122° 58' 55'' W44° 2' 2'' N
122° 58' 44'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84
0 50 100 200 300
Feet
0 20 40 80 120
Meters
Map Scale: 1:1,500 if printed on A portrait (8.5" x 11") 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—Nov 1,
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
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
1/24/2024
Page 2 of 3
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
24 Chapman loam 4.9 66.5%
29 Cloquato silt loam 0.9 12.6%
96 Newberg loam 0.4 4.9%
W Water 1.2 16.0%
Totals for Area of Interest 7.4 100.0%
Soil Map—Lane County Area, Oregon
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
1/24/2024
Page 3 of 3
Lane County Area, Oregon
24—Chapman loam
Map Unit Setting
National map unit symbol: 235z
Elevation: 300 to 1,000 feet
Mean annual precipitation: 40 to 60 inches
Mean annual air temperature: 52 to 54 degrees F
Frost-free period: 165 to 210 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Chapman and similar soils:85 percent
Estimates are based on observations, descriptions, and transects of
the mapunit.
Description of Chapman
Setting
Landform:Stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Alluvium from mixed sources
Typical profile
H1 - 0 to 8 inches: loam
H2 - 8 to 42 inches: loam
H3 - 42 to 50 inches: gravelly sandy loam
H4 - 50 to 60 inches: very gravelly sandy loam
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water
(Ksat):Moderately high to high (0.57 to 1.98 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:Rare
Frequency of ponding:None
Available water supply, 0 to 60 inches: Moderate (about 8.1
inches)
Interpretive groups
Land capability classification (irrigated): 1
Land capability classification (nonirrigated): 1
Hydrologic Soil Group: B
Ecological site: F002XC003OR - Low Flood Plain Group
Forage suitability group: Well drained < 15% Slopes
(G002XY002OR)
Map Unit Description: Chapman loam---Lane County Area, Oregon
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
1/24/2024
Page 1 of 2
Other vegetative classification: Well drained < 15% Slopes
(G002XY002OR)
Hydric soil rating: No
Data Source Information
Soil Survey Area: Lane County Area, Oregon
Survey Area Data: Version 22, Sep 8, 2023
Map Unit Description: Chapman loam---Lane County Area, Oregon
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
1/24/2024
Page 2 of 2
APPENDIX B:
Recommended Earthwork Specifications
GEOTECHNICAL SPECIFICATIONS
General Earthwork
1. All areas where structural fills, fill slopes, structures, or roadways are to be constructed shall be
stripped of organic topsoil and cleared of surface and subsurface deleterious material, including
but limited to vegetation, roots, or other organic material, undocumented fill, construction debris,
soft or unsuitable soils as directed by the Geotechnical Engineer of Record. These materials shall
be removed from the site or stockpiled in a designated location for reuse in landscape areas if
suitable for that purpose. Existing utilities and structures that are not to be used as part of the
project design or by neighboring facilities, shall be removed or properly abandoned, and the
associated debris removed from the site.
2. Upon completion of site stripping and clearing, the exposed soil and/or rock shall be observed by
the Geotechnical Engineer of Record or a designated representative to assess the subgrade
condition for the intended overlying use. Pits, depressions, or holes created by the removal of root
wads, utilities, structures, or deleterious material shall be properly cleared of loose material,
benched and backfilled with fill material approved by the Geotechnical Engineer of Record
compacted to the project specifications.
3. In structural fill areas, the subgrade soil shall be scarified to a depth of 4-inches, if soil fill is used,
moisture conditioned to within 2% of the materials optimum moisture for compaction, and
blended with the first lift of fill material. The fill placement and compaction equipment shall be
appropriate for fill material type, required degree of blending, and uncompacted lift thickness.
Assuming proper equipment selection, the total uncompacted thickness of the scarified subgrade
and first fill lift shall not exceed 8-inches, subsequent lifts of uncompacted fill shall not exceed 8-
inches unless otherwise approved by the Geotechnical Engineer of Record. The uncompacted lift
thickness shall be assessed based on the type of compaction equipment used and the results of
initial compaction testing. Fine-grain soil fill is generally most effectively compacted using a
kneading style compactor, such as a sheeps-foot roller; granular materials are more
effectively compacted using a smooth, vibratory roller or impact style compactor.
4. All structural soil fill shall be well blended, moisture conditioned to within 2% of the material’s
optimum moisture content for compaction and compacted to at least 90% of the material’s
maximum dry density as determined by ASTM Method D-1557, or an equivalent method. Soil fill
shall not contain more than 10% rock material and no solid material over 3-inches in diameter
unless approved by the Geotechnical Engineer of Record. Rocks shall be evenly distributed
throughout each lift of fill that they are contained within and shall not be clumped together in such
a way that voids can occur.
5. All structural granular fill shall be well blended, moisture conditioned at or up to 3% above of the
material’s optimum moisture content for compaction and compacted to at least 90% of the
material’s maximum dry density as determined by ASTM Method D-1557, or an equivalent
method. 95% relative compaction may be required for pavement base rock or in upper lifts of the
granular structural fill where a sufficient thickness of the fill section allows for higher compaction
percentages to be achieved. The granular fill shall not contain solid particles over 2-inches in
diameter unless special density testing methods or proof-rolling is approved by the Geotechnical
Engineer of Record. Granular fill is generally considered to be a crushed aggregate with a fracture
surface of at least 70% and a maximum size not exceeding 1.5-inches in diameter, well-graded
with less than 10%, by weight, passing the No. 200 Sieve.
6. Structural fill shall be field tested for compliance with project specifications for every 2-feet in
vertical rise or 500 cy placed, whichever is less. In-place field density testing shall be performed
by a competent individual, trained in the testing and placement of soil and aggregate fill
placement, using either ASTM Method D-1556/4959/4944 (Sand Cone), D-6938 (Nuclear
Densometer), or D-2937/4959/4944 (Drive Cylinder). Should the fill materials not be suitable for
testing by the above methods, then observation of placement, compaction and proof-rolling with a
loaded 10 cy dump-truck, or equivalent ground pressure equipment, by a trained individual may
be used to assess and document the compliance with structural fill specifications.
Utility Excavations
1. Utility excavations are to be excavated to the design depth for bedding and placement and shall
not be over-excavated. Trench widths shall only be of sufficient width to allow placement and
proper construction of the utility and backfill of the trench.
2. Backfilling of a utility trench will be dependent on its location, use, depth, and utility line material
type. Trenches that are required to meet structural fill specifications, such as those under or near
buildings, or within pavement areas, shall have granular material strategically compacted to at
least the spring-line of the utility conduit to mitigate pipeline movement and deformation. The
initial lift thickness of backfill overlying the pipeline will be dependent on the pipeline material,
type of backfill, and the compaction equipment, so as not to cause deflection or deformation of the
pipeline. Trench backfill shall conform to the General Earthwork specifications for placement,
compaction, and testing of structural fill.
Geotextiles
1. All geotextiles shall be resistant to ultraviolet degradation, and to biological and chemical
environments normally found in soils. Geotextiles shall be stored so that they are not in direct
sunlight or exposed to chemical products. The use of a geotextile shall be specified and shall meet
the following specification for each use.
Subgrade/Aggregate Separation
Woven or nonwoven fabric conforming to the following physical properties:
Minimum grab tensile strength ASTM Method D-4632 180 lb
Minimum puncture strength (CBR) ASTM Method D-6241 371 lb
Elongation ASTM Method D-4632 15%
Maximum apparent opening size ASTM Method D-4751 No. 40
Minimum permittivity ASTM Method D-4491 0.05 s-1
Drainage Filtration
Woven fabric conforming to the following physical properties:
Minimum grab tensile strength ASTM Method D-4632 110 lb
Minimum puncture strength (CBR) ASTM Method D-6241 220 lb
Elongation ASTM Method D-4632 50%
Maximum apparent opening size ASTM Method D-4751 No. 40
Minimum permittivity ASTM Method D-4491 0.5 s-1
Geogrid Base Reinforcement
Extruded biaxially or triaxially oriented polypropylene conforming to the following physical properties:
Peak tensile strength
lb/ft
Tensile strength at 2% strain
ASTM Method D-6637
ASTM Method D-6637
925
300
lb/ft
Tensile strength at 5% strain
ASTM Method D-6637
600
lb/ft Flexural Rigidity ASTM Method D-1388 250,000 mg-cm
Effective Opening Size ASTM Method D-4751 1.5x
rock size