GR 03-21 OR UNION 101(1) North Powder River Lane Reconstruction Final Geotech Recommendations Report.pdf

North Powder River Lane Reconstruction March 2021

Table of Contents 1-i

Geotechnical Report No. 03-21

North Powder River Lane Reconstruction

FINAL GEOTECHNICAL

RECOMMENDATIONS REPORT

OR UNION 101(1)

Union County, Oregon

March 2021

REVISED April 16, 2021

This page intentionally left blank

Table of Contents i

TABLE OF CONTENTS

1 INTRODUCTION

1.1 Project Description

1.2 Purpose and Scope

2 GEOLOGY

3 SITE CONDITIONS

3.1 Average Temperatures and Precipitation

4 SUBSURFACE CONDITIONS

5 GEOTECHNICAL RECOMMENDATIONS

5.1 Subexcavation

5.2 Edge stabilization

6 CONSTRUCTION CONSIDERATIONS

6.1 Excavation

6.2 Excavated material reuse

7 LIMITATIONS

8 REFERENCES

List of Figures ii

LIST OF FIGURES

Figure 1-1 Project Location Map

Figure 1-2 Project vicinity Map

Figure 3-1 Photograph of alignment constructed on shallow embankment

Figure 3-2 Photograph of slight benching into toe of older river terracing

Figure 3-3 Photograph of fatigue cracking showing weak subgrade conditions

Figure 3-4 Photograph of rutting and weak subgrade conditions in wheel path

Figure 3-5 Photograph of ponding water in cut-side ditch

Figure 3-6 Photograph of saturated soil conditions at toe of roadway embankment

Figure 3-7 Photograph of edge loss and undermining

Figure 3-8 Photograph of cut slope above the road’s drainage ditch

Figure 5-1 Recommended design detail for subexcavation repair areas

Figure 5-2 Recommended design details for the shoulder repair areas

LIST OF TABLES

Table 3-1 Climate Data Summary

Table 4-1 Asphalt pavement and base course thicknesses and depth to bottom of fill

Table 4-2 Soil Classifications

APPENDICES

APPENDIX A

Web Soil Survey Report

APPENDIX B

Boring Location Map

APPENDIX C

Field Classifications for Soil and Rock

Unified Soil Classification System

Boring Logs PL20-01 to PL20-11

APPENDIX D

Laboratory Test Reports

Introduction 3

1 INTRODUCTION

This report provides geotechnical investigation results and final geotechnical recommendations for the North Powder River Lane Reconstruction project. Determination of final recommendations stem from a subsurface investigation, resultant boring logs, laboratory testing of selected samples, and further surficial assessments of provided design options.

1.1 PROJECT DESCRIPTION

The project is 3.8 miles long and located in eastern Oregon along a two-lane, paved, rural roadway near the town of North Powder, Oregon. It begins on North Powder Lane at approximate latitude, longitude coordinates 45.02507°, -117.92765° (World Geodetic System [WGS] 84) and ending on Ellis Road about 44.99595°, -117.99306°. The project alignment is between Interstate

84 (I-84) and the Anthony Lake Highway, which is part of the Elkhorn Drive Scenic Byway. In addition to providing access for local residents and agricultural lands, the route provides year-round recreational access to a significant portion of the Wallowa-Whitman and Umatilla National

Forests. Figures 1-1 and 1-2 are project location and vicinity maps.

1.2 PURPOSE AND SCOPE

The purpose of this report is to provide geotechnical recommendations for reconstruction design and construction considerations. The geotechnical scope of work included a visual reconnaissance along the proposed alignment, a subsurface exploration program consisting of eleven subgrade test borings, laboratory soil testing, preparation of a preliminary geotechnical recommendations memorandum, reviewing the site with a highway designer to further identify subgrade improvement, edge stability, and drainage methods to improve the design, and preparation of this report. Subgrade borings were completed by a drilling contractor and logged by a subcontracted logging geologist under the direction of a Western Federal Lands Highway

Division (WFLHD) engineering geologist. Material laboratory testing was completed by the

WFLHD Materials Lab.

Geotechnical memorandum GM 40-20, Preliminary Geotechnical Recommendations, was previously prepared by WFLHD and is available upon request.

Note that this report and recommendations herein supersedes the previous memorandum for this project.

4 Introduction

Figure 1-1 Project Location Map

Figure 1-2 Project vicinity Map

Geology 5

2 GEOLOGY

Geology along the corridor is mapped at a large scale and described as either unconsolidated fluvial (river) gravel, sand, and silt or older sedimentary rocks that are mostly fluvial silt, sand, and gravel with partly indurated (hardened) minor tuff (Walker, 1979).

A custom soil resource report was compiled from Web Soil Survey for the project vicinity. Soils mapped within proximity of the alignment are mostly classified as a silt loam. Mapped soils are described as generally well drained and having horizons (layers) of sand and silt loam, but also varying amounts of clay and gravel. A cemented material horizon (layer) is described in some of the soils approximately 30 to 40 inches in depth. The custom soils report is provided in Appendix

A.

3 SITE CONDITIONS

Site conditions were observed during site visits by WFLHD Engineering Geologist Orion George and WFLHD Material Engineers Megan Chatfield and Aaron Coenen on April 30, 2020. A second field visit occurred on September 14, 15, and 16, 2020 by Orion George and WFLHD Design

Engineer Thinh Phan. Reconnaissance included visual inspection of road surface conditions, fill slopes, and drainage ditches and structures.

Doug Wright, Director of Union County Public Works, was on site September 15, 2020 to discuss the roadway maintenance history and problem areas. He communicated at that time the roadway had been chip sealed in 2015, which concealed most of the pavement distress.

Reconnaissance included visually inspecting road surface conditions, fill slopes, drainage ditches and structures. The roadway is in a flat-bottomed valley with the project beginning at approximately 3,275 feet elevation and ending with an elevation gain of 115 feet over 3.8 miles.

Much of the roadway was constructed on shallow embankments (Figure 3-1) elevating it above the valley floor, with some slight benching into, or construction up against older river terraces at some locations (Figure 3-2). The alignment does not cross natural drainages, but does cross an irrigation ditch in multiple locations.

During the site visits we observed evidence of weak subgrade conditions such as fatigue cracking and rutting in the wheel paths as shown in Figures 3-3 and 3-4.

The project is in an agricultural area that is actively irrigated. Due to the generally flat topography and low gradient we observed areas where drainage away from the roadway is not being achieved effectively. Under some circumstances standing water can lead to undesirable wet subgrade conditions. Figure 3-5 shows an example of water ponding in a ditch. At another location, we observed wet conditions present on both sides of the roadway embankment, as pointed out, but not visible in Figure 3-6. Irrigation ditches above the roadway may also contribute groundwater flow and elevated moisture contents to subgrade soils below the roadway.

6 Site Conditions

Figure 3-1 Example of alignment constructed on shallow embankment and cut into the edge of an older river terrace. Note the irrigation ditch in the left.

Figure 3-2 Example of slight benching into toe of older river terracing (photo date 5/2012).

Note the surface water ponding in the drainage ditch. Note rutting, cracking, and asphalt patches in this older photograph.

4/20/2020

Site Conditions 7

Figure 3-3 Example of fatigue cracking showing weak subgrade conditions.

Figure 3-4 Example of rutting and weak subgrade conditions in wheel path.

Fatigue cracking in wheel path

8 Site Conditions

Figure 3-5 Example of ponding water in cut-side ditch. An irrigation ditch is located approximately 20 feet from the top of the cut slope (red arrow). The approximate location of Figure 3-8 is highlighted by the red circle.

Figure 3-6 Locations of saturated soil conditions observed at the toe on both sides of the roadway embankment.

Ponding conditions

Wet ground

Wet ground

Site Conditions 9

Non-vegetated and some loose embankment slopes were observed through much of the project as seen in Figure 3-7. Factors such as the lack of vegetation, insufficient shoulders, minimal bench width, and potential for raveling and erosion in loose embankment fill has led to a condition where pavement edge loss and damage has occurred, or undermining of the edge is imminent. In some cases, edge loss or damage may be caused by traffic traveling too close to, or off the paved surface edge.

Figure 3-7 Edge loss and undermining possibly due to erosion, loose embankment fill, and lack of vegetation. Note the tire tracks over the pavement edge (red arrows).

At approximately station 184+60, a 13.5 feet high, 46° cut slope was observed failing into the roadway drainage ditch. Materials observed on the surface of the cut slope were loose and composed of fine grained sandy, SILT with rounded gravel and minor cobbles. Dead vegetative material and logs are incorporated into the loose soils. Vegetation was sparse on the slope, but is present in undisturbed areas with grasses, small shrubs, and young trees.

An irrigation ditch is located directly north of North Powder River Lane at this site, starting at approximately station 176+00, and flows west becoming closer to the road, in elevation and laterally, until it transmits under the roadway at approximately station 194+40 (Figure 3-5). At the top of the slope near station 184+60, the irrigation ditch is offset horizontally from the top of the cut slope about 20 feet. Loose, surficial material described above is likely being wasted from dredging of the irrigation ditch directly onto the face of the road cut slope (Figure 3-8). This is oversteepening the cut slope and allowing material to fail into the drainage ditch, which impedes flow and reduces the drainage ditch’s effectiveness. Similar, past shallow failures were observed along this cut slope between the stationing provided above.

10 Site Conditions

Figure 3-8 Photograph of cut slope above the road’s drainage ditch at approximately station

184+40. The irrigation ditch is offset about 20 feet from the top of the slope. The red circled area is loose, mostly fine grained material likely dredged from the irrigation ditch, which is oversteepening the cut slope. The oversteepened cut slope is failing into the drainage ditch (red arrow). This site is highlighted in Figure 3-5.

We observed no surficial evidence of distressed pavement as a result of frost heaving or freeze-thaw conditions, but that may have been due to the fairly recent chip seal reportedly completed in 2015.

3.1 AVERAGE TEMPERATURES AND PRECIPITATION

Table 3-1 shows the average maximum and minimum temperatures, average monthly precipitation, and average monthly snowfall data for the period from 1911 to 2012 for the Union

Exp Stn, Oregon (358746) weather station (Western Region Climate Center, 2021).

5/15/2020

Subsurface Conditions 11

Table 3-1 Climate Data Summary

4 SUBSURFACE CONDITIONS

A subsurface investigation was conducted to support design for the project. It consisted of 11 subgrade borings, designated PL20-01 through PL20-11, and were drilled in late April 2020 by

Haztech Drilling, Inc. from Nampa, Idaho, using a CME 75 truck-mounted drill rig. Geotechnical logging services were subcontracted through Haztech Drilling with Materials Testing and

Inspection (MTI). All borings were advanced to five feet below ground surface (bgs) using a 16-inch outside diameter (OD) auger bit with a 12-inch solid stem auger flight. Bulk samples and individual moisture samples were collected for potential testing and to assess natural moisture content of subsurface soils encountered. Note the moisture content is specific to boring locations and conditions at the time of drilling. Boring location maps are included in Appendix B, boring logs in Appendix C, and material laboratory test results in Appendix D.

Except for PL20-04, drilling encountered predominantly granular materials. The soil was comprised of layers interpreted as: roadway aggregate base, roadway fill, and native in-situ soils.

Table 4-1 provides information regarding asphalt thickness, base thickness, and interpreted depth to the bottom of fill layers encountered in the test holes. Except for PL20-09, asphalt pavement thicknesses ranged from 4.0 to 7.0 inches in the borings. PL20-09 was drilled off the paved travel way at about 30 feet right of centerline. Thickness of the encountered base layers ranged from

0.55 to 1.5 feet, and the depth to the bottom of fill materials ranged from 1.5 feet to the bottom of the hole (BOH).

No groundwater was encountered in any of the subgrade borings. However, it is anticipated groundwater is infiltrating and wetting the subgrade from irrigation ditches located close to, and above the roadway, particularly in the vicinity of station 176+00 to 184+60 (Figures 3-5 and 3-8).

The irrigation ditch is about 60 feet from the roadway drainage ditch near station 176+00, but becomes increasingly closer to the road prism before it eventually goes under North Powder River

Lane at station 184+60.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

Avg. Max.

Temp. (F) 37 43 51 59 67 74 84 84 75 62 48 39 60.1

Avg. Min.

Temp. (F) 24 27 30 34 40 45 49 48 41 35 31 26 35.7

Avg. Total

Precip. (in.)

1.1 0.9 1.2 1.4 1.8 1.6 0.5 0.7 0.9 1.1 1.3 1.2 13.77

Avg. Total

Snowfall (in.)

7.1 4.4 2.7 0.7 0.7 0 0 0 0 0.2 2.4 5.2 22.8

Avg. Snow

Depth (in.)

1 1 0 0 0 0 0 0 0 0 0 1 0

2. Percent of possible observations for period of record: Max. Temp.: 99.2% Min. Temp.:

99.2% Precipitation: 99.3% Snowfall: 99.3% Snow Depth: 99.3%.

Note:

1. Period of Record : 10/01/1911 to 04/16/2012.

12 Subsurface Conditions

Table 4-1 Asphalt pavement and base course thicknesses and depth to bottom of fill.

Boring Designation

Approximate Station

Asphalt thickness, in.

(feet bgs1)

Base thickness, ft

(feet bgs)

Depth to Bottom of Fill, ft

PL20-01 3+00 6.0 (0.5) 1.5 (2.0) Bottom of hole2

PL20-02 29+40 4.0 (0.33) 0.58 (0.91) 3.5

PL20-03 56+40 4.0 (0.33) 0.75 (1.08) Bottom of hole

PL20-04 83+30 4.0 (0.33) 0.55 (0.88) 3.5

PL20-05 96+90 7.0 (0.58) 0.6 (1.18) Bottom of hole

PL20-06 127+20 4.0 (0.33) 0.75 (1.08) 3

PL20-07 163+60 4.0 (0.33) 0.55 (0.88) 1.5

PL20-08 190+20 6.5 (0.54) 0.55 (1.09) 2.6

PL20-09 3 213+00 NA NA 0.2 4

PL20-10 213+00 4.0 (0.33) 0.95 (1.28) 4

PL20-11 236+20 4 0.75 Bottom of hole

Notes:

1. bgs = below ground surface.

2. All subgrade borings were drilled to 5 feet depth.

3. PL20-09 drilled off paved travel way.

4. The gravel layer encountered off-road at this location is interpreted as fill.

Select samples were submitted to the WFLHD materials testing laboratory for index tests to show soil classification, grain size distribution, apparent specific gravity, Atterberg limits, natural moisture content, and R-value. Note that not all tests were performed on all samples that were tested. Remaining samples were classified visually using the Visual/Manual Method, Standard

Practice for Description and Identification of Soils, ASTM D2488. Tests classify materials as sand and gravels with smaller or minor constituent quantities of silt and clay; although, the visual/manual method used to classify PL20-04 showed native in-situ soils to have a significant clay content. Resulting classifications from both methods are shown in Table 4-2. Note that the

Unified Soil Classification System (USCS) group symbols and group names are provided only where laboratory tests for classification are performed.

Moisture conditions were found to be dry in all base layers encountered. Fill layers were found to be dry in most cases, but in PL20-10 and PL20-11 the fill layers were found to be moist. Native in-situ soils were found to be dry in all borings except for PL20-08, where moist conditions were observed.

R-value tests were performed on four samples from two of the boreholes. Results from the tests ranged from 27 in PL20-08 at 1.1 to 2.6 feet bgs to 59 in PL20-10 at 1.5 to 2.6 feet bgs (Appendix

D).

Subsurface Conditions 13

Table 4-2 Soil Classifications. Approximate stationing of boreholes is in Table 4-1.

Layer

Soil Classifications based on laboratory tests (USCS group symbol)1

Soil Classifications based on the Visual/Manual Method (ASTM 2488)

Borehole Designations

Base

Poorly-graded gravel with clay and sand (GP-GC)

--- PL20-02

Clayey gravel with sand

(GC)

--- PL20-08 & PL20-10

Poorly graded gravel with sand

PL20-01, PL20-03,

PL20-05, & PL20-11

Poorly graded gravel with clay and sand

PL20-04, PL20-06,

PL20-07

Fill

Clayey sand with gravel

(SC)

--- PL20-02

Well graded gravel with clay and sand (GW-GC)

--- PL20-08

Well graded sand with clay and gravel (SW-SC)

--- PL20-10

Poorly graded sand with clay and gravel

PL20-01

--- Clayey sand with gravel PL20-03, PL20-04 and

PL20-05

Poorly graded gravel with clay and sand and silty sand with gravel

PL20-11

--- Silty sand with gravel PL20-11

Native, in-situ soils

Clayey sand with gravel

(SC)

--- PL20-02

Clayey sand (SC-SM) --- PL20-08

Silty sand (SM) --- PL20-10

--- Sandy lean clay with gravel PL20-04

--- Silty sand with gravel PL20-06, PL20-07

--- Clayey gravel with sand PL20-07

Poorly graded gravel with clay and sand

PL20-09

Notes:

1. USCS group names and group symbols are only provided when laboratory tests are performed to make that determination. When the visual/manual method is used, only group names are provided.

14 Geotechnical Recommendations

5 GEOTECHNICAL RECOMMENDATIONS

This section presents geotechnical recommendations that address areas where distressed or damaged conditions were observed. The recommendations are designed to address mechanisms causing distress and are anticipated to reduce risk of similar pavement damage in the future.

5.1 SUBEXCAVATION

As discussed above, there are areas with poor, weak subgrade conditions which are not supporting overlying pavement sufficiently. Partly this is due to higher fines content in subgrade materials, but also groundwater infiltration and wetting from poor drainage ditch flow and upland irrigation ditches. To address the poor subgrade conditions, we recommend subexcavation in the two locations listed below:

• Station 101+70 to 103+75

• Station 184+00 to 190+65

It is anticipated subexcavating and reconstructing the subgrade will increase strength and total support to the overlying pavement structure in these locations. This is anticipated to improve long-term performance of the pavement structure. We recommend subexcavating according to FP-14, Section 204 to 24 inches in depth, lining the excavation with a Class 1, Type C (woven) separation-stabilization geotextile meeting the requirements in Section 714, and filling and compacting with select borrow meeting the requirements of Section 704.07. Figure 5-1 is a typical design detailing this recommended work.

Figure 5-1 Recommended design detail for subexcavation repair areas.

Areas of standing water were also described at these subexcavation sites, and likely contribute groundwater infiltration and wetting to the subgrade, and subsequently weakening it. This groundwater infiltration lowers underlying support for the pavement structure. We recommend that in these areas ditches be reconditioned by cleaning and excavating to promote positive drainage away from the pavement structural section. Ditch reconditioning should occur at the subexcavation sites listed above.

Additionally, two new culverts will be added in the subexcavation site from station 184+00 to

190+65. The new culverts are anticipated at approximate stationing 184+90 and 187+15. The

Geotechnical Recommendations 15 new culverts will require additional excavation to promote positive drainage to the new culverts’ inlets, which will allow for quicker transmission of surface waters to the lower elevation side of the roadway. Depth of ditch excavation will be limited along this site due to close proximity of an irrigation ditch directly above, and north of the roadway’s ditch. Consult Section 6 Construction

Considerations for more information.

5.2 EDGE STABILIZATION

Some lengths of the project are experiencing pavement breaking and loss due to undermining at the pavement edge and shoulder traffic (Figure 3-7). To alleviate this type of distress we recommend stabilizing the edge of the shoulder to strengthen the subgrade. Shoulder edge areas recommended for edge stabilization are:

• Station 39+85 to 42+35 RT

• Station 45+55 to 48+20 LT

• Station 73+00 to 76+25 LT

• Station 197+75 to 200+00 LT.

Edge stabilization construction involves removing the pavement at the shoulder and outside edge of the travel surface and reconstructing the subgrade. This is anticipated to improve the long-term performance of the outside edge of the pavement structure as well. We recommend subexcavating according to FP-14, Section 204, to 24 inches in depth, lining the excavation with a Class 1, Type C (woven) separation-stabilization geotextile meeting the requirements in Section

714, and filling and compacting with roadway aggregate as detailed in Figure 5-2 and Section

703.05, Table 703-2 Grading Designation A (Subbase). Edge stabilization designs for the project are expected to minimize impacts from ongoing erosion and shoulder traffic by stabilizing the outside edge of the paved surfaces and shoulders. Figure 5-2 is a typical design detail of the work recommended.

Figure 5-2 Recommended design details for the shoulder edge repair areas.

16 Construction Considerations

6 CONSTRUCTION CONSIDERATIONS

6.1 EXCAVATION

Conform to Section 204 of the FHWA Standard Specifications FP-14 for all excavations.

Bedrock or boulders are not anticipated to be encountered during excavations associated with this project. However, if encountered, excavate larger material and fill any voids with select borrow or recycled aggregate base (as quantities allow) and compact in accordance with Section 204.

Subgrade soils should be proof-rolled or otherwise compacted prior to placement of fill material.

Care should be given to any cutslope and ditch reconditioning work from station 176+00 to 184+60 due to the proximity of the irrigation ditch above the roadway prism. The slope above this roadway is oversteepened and likely experiences higher moisture contents due to the irrigation ditch carrying water, even in prolonged dry weather conditions. The cut slope should not be steepened greater than it already is (measured at 46° in September 2020) and the toe of the cut slope should not be undermined, which could further reduce the already marginal stability of the slope.

6.2 EXCAVATED MATERIAL REUSE

Subgrade soils are expected to consist primarily of granular, non-plastic soils. Laboratory tests performed on samples of base material showed fines content averaged approximately 12%. This suggests base material would be potentially suitable for reuse as a recycled aggregate base.

Subgrade soil fines content ranged from 10.5 to 37.6%, so subgrade soils are unsuitable for use as select borrow. If suitable soils are encountered and the Contractor should desire to use onsite materials, it will be the Contractor’s responsibility to ensure those materials meet contract requirements for specific reuses. All excavation from the wet ditch reconditioning sections should be considered waste and be removed in accordance with contract requirements.

Limitations 17

7 LIMITATIONS

This report was prepared to provide geotechnical investigation results and recommendations for the North Powder Lane Reconstruction project. Professional judgments and recommendations are presented in this report. They are based partly on evaluation of technical information gathered for this project and partly on the Geotechnical Team’s general experience with subsurface conditions in the area. It should be noted borings might not represent potentially unfavorable subsurface conditions away from the borings. Observed conditions indicated on the logs are as recorded at the time of exploration. Groundwater conditions may vary considerably, with season/time, changes in climate, rainfall, and other factors and are otherwise dependent on the duration of, and methods used in, and interpretations made from the exploration program.

If soil conditions are encountered during construction that vary from those discussed in this report, or if configurations change, the WFLHD Geotechnical Team should be notified immediately in order to evaluate what effects, if any, the changes have on recommendations contained in this report. The recommendations presented in this report are applicable only to this specific site.

These data are not to be used for other purposes.

Questions regarding this report should be addressed to Orion George, WFLHD Engineering

Geologist, at (360) 619-7634, or Orion.George@dot.gov.

mailto:Orion.George@dot.gov

18 Limitations

GEOTECHNICAL REPORT NO. 03-21

FINAL GEOTECHNICAL RECOMMENDATIONS REPORT

North Powder Lane Reconstruction Project

OR UNION 101(1)

Union County, Oregon

March, 2021

REVISED April 16, 2021

Prepared by: _________________________________________

Orion George, Engineering Geologist

Reviewed by: _________________________________________

Robert Kraig, Geotechnical Engineer

Reviewed and

Approved by: _________________________________________

Douglas A. Anderson, Geotechnical Team Lead

References 19

8 REFERENCES

Walker, G.W., 1979, Reconnaissance geologic map of the Oregon part of the Grangeville quadrangle, Baker, Union, Umatilla, and Wallowa Counties, Oregon, USGS

Miscellaneous Investigations Series, Map I-1116, 1 sheet.

Western Regional Climate Center (2021), Cooperative Climatological Data Summaries, Gardiner, Montana (243378): http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?mt3378, accessed

February 5, 2021.

http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?mt3378

APPENDIX A

Web Soil Survey Report (31 pages)

United States Department of Agriculture

A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants

Custom Soil Resource Report for Baker County Area, Oregon, and Union County Area, Oregon North Powder Lane Reconstruction

Natural Resources Conservation Service

July 27, 2020

Preface Soil surveys contain information that affects land use planning in survey areas.

They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers.

Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment.

Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions.

The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations.

Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?

cid=nrcs142p2_053951).

Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations.

The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey.

Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/health/ http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/health/ https://offices.sc.egov.usda.gov/locator/app?agency=nrcs http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?cid=nrcs142p2_053951 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?cid=nrcs142p2_053951 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.

Contents Preface How Soil Surveys Are Made Soil Map

Soil Map Legend Map Unit Legend Map Unit Descriptions

Baker County Area, Oregon 40A—Cumulic Haploxerolls, 0 to 2 percent slopes 176A—Wingville silt loam, 0 to 2 percent slopes

Union County Area, Oregon 10B—Coughanour silt loam, 2 to 7 percent slopes 10C—Coughanour silt loam, 7 to 12 percent slopes 15C—Encina silt loam, 2 to 12 percent slopes 16E—Encina silt loam, 12 to 45 percent south slopes 26B—Hutchinson silt loam, 2 to 7 percent slopes 27D—Hutchinson gravelly silt loam, 1 to 20 percent slopes 62—Umapine silt loam 66—Veazie-Voats complex 71—Wingville silt loam 75A—Cumulic Haploxerolls, 0 to 2 percent slopes

References

How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity.

Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA.

The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape.

Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries.

Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units).

Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research.

The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas.

Soil scientists make many field observations in the process of producing a soil map.

The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded.

These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape.

Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties.

While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management.

Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil.

Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date.

After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and

Custom Soil Resource Report identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately.

Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit.

Soil Map

0421200 421900 422600 423300 424000 424700 425400 426100 426800 427500

421200 421900 422600 423300 424000 424700 425400 426100 426800 427500

45° 1' 45'' N

8°

' 9 '' W

45° 1' 45'' N

7°

5'

'' W

44° 59' 24'' N

8°

' 9

'' W

44° 59' 24'' N

7°

5'

'' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 1000 2000 4000 6000

Feet 0 450 900 1800 2700

Meters Map Scale: 1:30,700 if printed on A landscape (11" x 8.5") sheet.

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 scales ranging from 1:20,000 to 1:24,000.

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: Baker County Area, Oregon Survey Area Data: Version 15, Jun 11, 2020

Soil Survey Area: Union County Area, Oregon Survey Area Data: Version 16, Jun 11, 2020

Your area of interest (AOI) includes more than one soil survey area. These survey areas may have been mapped at different scales, with a different land use in mind, at different times, or at different levels of detail. This may result in map unit symbols, soil properties, and interpretations that do not completely agree across soil survey area boundaries.

Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

Date(s) aerial images were photographed: Jun 26, 2011—Sep 26, 2016

The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background

MAP LEGEND MAP INFORMATION

imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

Map Unit Legend

Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI

40A Cumulic Haploxerolls, 0 to 2 percent slopes

2.7 0.8%

176A Wingville silt loam, 0 to 2 percent slopes

1.4 0.4%

Subtotals for Soil Survey Area 4.0 1.3%

Totals for Area of Interest 319.8 100.0%

Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI

10B Coughanour silt loam, 2 to 7 percent slopes

45.3 14.2%

10C Coughanour silt loam, 7 to 12 percent slopes

0.8 0.2%

15C Encina silt loam, 2 to 12 percent slopes

9.9 3.1%

16E Encina silt loam, 12 to 45 percent south slopes

67.8 21.2%

26B Hutchinson silt loam, 2 to 7 percent slopes

3.0 0.9%

27D Hutchinson gravelly silt loam, 1 to 20 percent slopes

16.3 5.1%

62 Umapine silt loam 87.6 27.4%

66 Veazie-Voats complex 1.1 0.3%

71 Wingville silt loam 74.6 23.3%

75A Cumulic Haploxerolls, 0 to 2 percent slopes

9.5 3.0%

Subtotals for Soil Survey Area 315.8 98.7%

Totals for Area of Interest 319.8 100.0%

Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit.

A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class.

Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils.

Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape.

The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas.

An identifying symbol precedes the map unit name in the map unit descriptions.

Each description includes general facts about the unit and gives important soil properties and qualities.

Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement.

Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.

Some map units are made up of two or more major soils or miscellaneous areas.

These map units are complexes, associations, or undifferentiated groups.

A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps.

The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.

An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.

An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.

Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example.

Baker County Area, Oregon

40A—Cumulic Haploxerolls, 0 to 2 percent slopes

Map Unit Setting National map unit symbol: 22qs Elevation: 2,000 to 3,600 feet Mean annual precipitation: 9 to 20 inches Mean annual air temperature: 45 to 50 degrees F Frost-free period: 100 to 140 days Farmland classification: Prime farmland if irrigated

Map Unit Composition Cumulic haploxerolls and similar soils: 85 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit.

Description of Cumulic Haploxerolls

Setting Landform: Flood plains Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium

Typical profile H1 - 0 to 11 inches: loam H2 - 11 to 33 inches: sandy loam H3 - 33 to 60 inches: extremely gravelly sand

Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Moderately 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: About 24 to 48 inches Frequency of flooding: Occasional Frequency of ponding: None Available water storage in profile: Low (about 5.5 inches)

Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3w Hydrologic Soil Group: C Ecological site: LOAMY BOTTOM (R010XY005OR) Hydric soil rating: No

Minor Components

Riverwash Percent of map unit: 5 percent Landform: Flood plains Hydric soil rating: Yes

Boyce Percent of map unit: 5 percent Landform: Flood plains Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: WET MEADOW (R010XY003OR) Hydric soil rating: Yes

176A—Wingville silt loam, 0 to 2 percent slopes

Map Unit Setting National map unit symbol: 22pl Elevation: 2,000 to 3,600 feet Mean annual precipitation: 9 to 12 inches Mean annual air temperature: 45 to 50 degrees F Frost-free period: 110 to 140 days Farmland classification: Prime farmland if irrigated

Map Unit Composition Wingville and similar soils: 85 percent Minor components: 7 percent Estimates are based on observations, descriptions, and transects of the mapunit.

Description of Wingville

Setting Landform: Terraces, fans Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium with volcanic ash in the surface layer

Typical profile H1 - 0 to 8 inches: silt loam H2 - 8 to 40 inches: silt loam H3 - 40 to 60 inches: silty clay loam

Properties and qualities Slope: 0 to 2 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 1.98 in/hr) Depth to water table: About 18 to 36 inches Frequency of flooding: Rare Frequency of ponding: None Calcium carbonate, maximum in profile: 25 percent Available water storage in profile: Very high (about 12.2 inches)

Interpretive groups Land…