Attachment 8 - WhiteCityVA_Stormwater Facility Design.pdf

4 4 1 2 S W C O R B E T T A V E N U E

P O R T L A N D , O R 9 7 2 3 9

5 0 3 . 2 4 8 . 1 9 3 9 M A I N

8 6 6 . 7 2 7 . 0 1 4 0 F A X

P B S U S A . C O M

Central Stormwater Facility Design Report Southern Oregon Rehabilitation Center & Clinics

White City, OR

Prepared for:

William Wilson Architects

1022 SW Salmon Street, Suite 350

Portland, OR 97205

May 2020

PBS Project 70995.002

Central Stormwater Facility Design Report

William Wilson Architects

VA Southern Oregon Rehabilitation Center & Clinics

White City, OR ii

Table of Contents

1 OVERVIEW

2 SITE CONDITIONS

2.1 Existing Conditions

2.2 Site Soils

3 HYDROLOGY & HYDRAULICS

3.1 Drainage Areas

3.2 Storm System

3.3 Hydraulic Model

4 STORMWATER FACILITY DESIGN

4.1 Pre-Developed Condition

4.2 Facility Depth

4.3 Permanent Pool Sizing

4.4 Outlet Structures

4.5 Final Facility Dimensions and Access

4.6 Additional Modeling

4.7 Facility Operations and Maintenance

5 REFERENCES

Supporting Data

TABLES

Table 1: VA SORCC MS4 Land Cover Summary Table 2: Design Storm Event Summary Table 3: Drainage Area Properties Table 4: Wet Pond Water Quality Sizing Parameters Table 5: Wet Pond Facility Discharge Table 6: Wet Pond Facility Maximum Water Surfaces iii

FIGURES

Figure 1: VA SORCC Facility Location Map Figure 2: SORCC Site Topographic Contours Figure 3: SORCC MS4 Model Drainage Area Map Figure 4: VA SORCC Site Storm System Map Figure 5: Extended Detention Pond Facility Model Schematic Figure 6: Pre-Developed Discharge and Site Discharge to the Wetpond Facility Figure 7: Pre- and Post-Development Water Quality Event Discharge Figure 8: Pre- and Post-Development 10-year Site Discharge Figure 9: Pre- and Post-Development 25-year Site Discharge Figure 10: Former Driving Range Site and Topography Figure 11: Wet Pond Facility Siting and Layout Figure 12: Stage-Area-Storage Curves for the Existing Pond Figure 13: SSA Model Including Existing Pond and Design Pipe System Figure 14: Pre- and Post-Development Water Quality Event Site Discharge Figure 15: Pre- and Post-Development 10-year Site Discharge Figure 16: Pre- and Post-Development 25-year Site Discharge

APPENDICES

Appendix A: Web Soil Survey Map and Report

Appendix B: Drainage Area Calculations

Appendix C: SSA Model Output Reports

Appendix D: Stormwater Facility Drawings

©2019 PBS Engineering and Environmental Inc.

iv

CERTIFICATE OF ENGINEER

VA Southern Oregon Rehabilitation Clinics

The technical information and data contained in this report was prepared under the direction and supervision of the undersigned, whose seal, as a professional engineer licensed to practice as such, is affixed below.

Prepared by:

Justin R. Maynard, P.E.

JustinM

1 OVERVIEW

The VA SORCC facility is located in White City, OR along Crater Lake Highway north of Medford. The approximately 145-acre site is bound by Avenue L to the northeast, Crater Lake Highway to the southeast, and a golf course extending to the property lines to the west. The site boundary is defined by Jackson County

Assessor’s Taxlot number 361W17 800. The site is shown in Figure 1.

Figure 1: VA SORCC Facility Location Map

The current MS4 Permit, effective March 1, 2019 requires that pollutant reduction measures be taken to ensure that only stormwater is allowed to enter an MS4. The permit sets regulatory precedent for local management authority and establishment of acceptable design methodologies. In this case, The Rogue Valley

Stormwater Quality Design Manual (RVSQDM) serves as the local design guidance for selecting and implementing stormwater control facilities. The manual sets pollution reduction standards in line with the MS4 permit document and dictates flow control requirements to prevent potentially harmful increases in peak runoff from a drainage area. The RVSQDM also lists approved structural stormwater controls, whether they are considered LID, and whether structural measures can provide flow control.

While retention and LID measures are the preferred approach to stormwater management, the Permit and manual make provisions for deviations from the preferred stormwater retention and infiltration requirements where such practices are not feasible due to site conditions.

An alternatives analysis was prepared that explored potential stormwater detention and treatment facility measures for the Veteran’s Administration Southern Oregon Rehabilitation Center & Clinics (SORCC) to bring the site stormwater system into compliance with the National Pollutant Discharge Elimination System (NPDES)

Phase II permit (the “Permit”) for Municipal Separate Storm Sewer Systems (MS4). The analysis considered the following potential solutions and provided estimated costs of construction for each:

• Central detention and treatment pond

• Central detention pond with proprietary treatment device

• Central underground detention storage with proprietary treatment device

• Various small facilities throughout the site

Ultimately, SORCC Facilities Management Services indicated that underground storage wasn’t preferable and that a decentralized option with many fragmented facilities located throughout the SORCC campus does not meet the intent of the Project. Given the size of the former driving range site to be used for the facility, a large facility area and greater depth were deemed not to be an issue, making the wet pond alternative the preferred alternative.

This report will take more specific site conditions into consideration in support of a facility design for the preferred wet pond alternative.

2 SITE CONDITIONS

2.1 Existing Conditions

The VA facilities are situated on a relatively flat parcel that generally slopes from southeast to northwest. The approximately 88 acres site (not including the golf course) includes a dedicated Municipal Separate Storm

Sewer System (MS4) that discharges to a 36” pipe near the intersection of Avenue N, Avenue L, and Avenue K

West. The site includes streets, concrete sidewalks and walkways, landscaping, gravel surfacing, and buildings and other covered surfaces. Site cover is summarized in Table 1.

Table 1: VA SORCC MS4 Land Cover Summary

Cover Area (Acres)

Building 12.35

Concrete 4.95

Gravel 11.78

Landscape 29.89

Pavement 16.43

Total 75.40

The site’s topography is shown in Figure 2.

Figure 2: SORCC Site Topographic Contours

2.2 Site Soils

The Web Soil Survey database, administered by the US Department of Agriculture (USDA), provides an evaluation of soil types present around the Project site. According to the database, the site is underlain entirely by Agate-Winlo complex soils with mild slopes.

This soil map unit consists dominantly of well-drained Agate series soils (~55%) composed of fine loam alluvium with relatively shallow Duripan subsurface. Agate soils are generally categorized as Hydrologic Soil

Group (HSG) C for purposes of estimating stormwater runoff. Approximately 35% of the site soil unit is categorized as poorly drained Winlo series alluvium made up of gravelly clay loam materials. Winlo soils have somewhat lower transmissivity and are categorized as HSG D.

• Infiltration testing results as applicable

• Takeoffs showing impervious area acreage to be developed/redeveloped, and pervious area acreage

• Map showing redevelopment conditions, contours and sources of all on and offsite stormwater flows for each stormwater facility

The Web Soil Survey map and report are provided in Appendix A

3 HYDROLOGY & HYDRAULICS

The RVSQDM allows the use of Santa Barbara Urban Hydrograph Method modeling of a NOAA Type 1A, 24-hour storm in the design of treatment and flow control facilities. Design storm requirements are summarized in Table 2.

Table 2: Design Storm Event Summary

Event Event Depth (in)

Treatment N/A 1.00

Flow Control (Peak) 10-yr 3.00

Flow Control (Overflow) 25-yr 3.25

Due to the size and complexity of the system, the AutoDesk Storm and Sanitary Analysis (SSA) model, which implements the EPA SWMM solver, was chosen to develop hydraulic grade line calculations for the storm system and size detention facilities for each alternative. The model is capable of using SBUH methodology to develop runoff hydrographs for each drainage area and uses Hydrodynamic routing (which solves Saint

Venant equations) to establish hydraulic grade lines through pipe systems and storage facilities. This approach considers pressurized flow, backwater effects, and flow reversal that occur in the system during large storm events.

3.1 Drainage Areas

Drainage areas for the MS4 have been delineated based on site topography and the layout of the on-site

MS4. The site is broken into 33 areas, each with a calculated empirical Curve Number value for use with the

SBUH method and a time of concentration, estimated based on TR-55 guidance in accordance with the

RVSQDM. Basin boundaries are defined to capture areas of generally similar characteristics (land cover, flow path, lateral lengths, etc).

Curve numbers for each area are based on current land cover conditions and HSG C soil types throughout the site. Drainage area boundaries and current land cover conditions are shown in Figure 3.

Figure 3: SORCC MS4 Model Drainage Area Map.

The pre-developed basin is assumed to be a single, contiguous basin area covering the entire model area shown in Figure 3 with no impervious surface and a “Pasture” condition representing farmland conditions surrounding the site.

Drainage area properties used as inputs to the hydrologic model are provided in Table 3. Appendix B includes drainage area properties used to calculation time of concentration values.

Table 3: Drainage Area Properties

Basin Total Area

(Acre) Pervious

CN

Percent

Impervious

Time of Conc.

(min)

A1 1.86 79 11 27.7

A2 1.57 79 19 21.3

B1 2.20 79 47 26.4

B2 1.89 79 39 22.5

B3 3.67 79 30 25.6

C1 3.48 80 52 22.5

C2 2.20 84 73 3.6

C3 1.73 81 52 4.2

D1 4.13 79 24 21.5

D2 5.66 81 38 40.0

D3 2.92 82 52 23.8

D4 2.15 79 49 17.3

D5 1.02 85 51 20.5

D6 1.95 83 62 26.8

D7 2.11 82 59 22.5

E1 1.84 79 22 18.1

E2 1.95 79 13 11.8

E3 0.72 87 33 4.7

E4 4.55 82 23 16.4

E5 3.03 85 90 11.7

E6 2.38 84 54 6.0

F1 0.95 82 67 9.4

F2 2.32 88 82 3.5

F3 3.94 83 41 14.5

F4 5.53 88 57 10.0

F5 0.67 79 47 6.1

F6 2.41 89 59 12.5

G1 2.41 89 23 9.8

G3 0.88 81 39 9.5

H1 0.97 81 45 10.3

H2 1.13 79 50 2.8

J1 0.77 85 35 3.3

J2 0.41 79 33 6.2

Pre-Developed 75.40 79 0 62

3.2 Storm System

The storm system has been skeletonized to include primary conveyance lines (i.e. not all catch basins and laterals have been modeled). Pipes not included in the hydraulic model have been considered in the calculation of Time of Concentration values for each drainage area summarized in Section 4.1 where necessary. The modeled system is shown in Figure 4.

Figure 4: VA SORCC Site Storm System Map

3.3 Hydraulic Model

The pre-development hydrology model forms the baseline for this analysis, setting the target 10-year peak flow that must be matched with a detention facility. No pre-developed hydraulics model is necessary, as no pipe systems existed and assumptions have been made in the hydrology model regarding flow paths across the site prior to the presence of “planned development.” The pre-developed hydrology scenario is therefore modeled simply as a single basin with pasture cover and Type C soils.

A hydraulic model of the existing pipe system was developed; however, the existing pipe system was previously studied and a large-scale, phased improvement project planned. The hydraulic model has therefore been adjusted to represent the improved, “future” condition that will be properly sized to allow runoff from the campus to reach the system discharge.

A storage element has been added to the MS4 model to estimate the necessary conveyance sizing and storage volume required to meet water quality and flow control requirements for discharge from the pipe system. This storage element has been used to estimate storage volume and outlet sizing required for the planned wet pond (or “Extended Detention Facility”)

The model assumes that all flow is routed through the treatment and storage facility prior to discharge downstream. A combined facility is subject to minimum permanent pool volume and hydraulic loading rates dictated by the treatment event’s daily volume. This facility must be sized to settle out pollutants with sufficient efficiency to meet pollution reduction requirements of the MS4. The model also includes outlet structures necessary to meet these requirements and conveyance piping to the discharge point.

Figure 5: Extended Detention Pond Facility Model Schematic.

New Conveyance to Pond Site

Location of

Existing 36”

Discharge Pipe

Low Flow Orifice and Overflow

Riser

Replace 27”

Pipe (Reverse

Slope)

4 STORMWATER FACILITY DESIGN

The preferred facility has been designed using the same model as was used in the Alternatives Analysis with some refinement to the pipe system. The facility has been designed without considering existing ponds nearby at the golf course. Should those ponds be abandoned, filled, or otherwise decommissioned, this facility will continue to provide full water quality and flow control benefits for the SORCC facilities.

Should those ponds remain operational, the existing capacity provides a buffer for future improvements and development on the SORCC site. A model has also been developed with the existing pond and outlet structure included that could be used for future projects to satisfy flow control and water quality requirements.

4.1 Pre-Developed Condition

The RVSQDM utilizes the pre-development 10-year peak discharge as the benchmark for flow control facility design. Based on the results from the hydrology model, this peak discharge is approximately 8.91 cfs. The existing site produces approximately 28.88 cfs to the facility at the peak as shown in, creating the need for detention storage.

Figure 6: Pre-Developed Discharge and Site Discharge to the Wetpond Facility.

4.2 Facility Depth

The wet pond requires that all flow from the MS4 be routed through the permanent pool, providing mixing and treatment below the discharge invert, and the “live” detention storage above. The bottom elevation of the live storage range is therefore dictated primarily by the pipe profile routing flow from the existing 36” discharge pipe to the pond.

Approximately 400 linear feet of pipe adjacent to Avenue L must be reconstructed to slope in the direction of the facility. Utilizing 36-inch diameter pipe with a slope of 0.15% results in a discharge invert of approximately

1,310.00 ft NAVD.

It is not possible to route runoff back to the existing 36-inch discharge pipe; however, that pipe will remain in place and open so that runoff can also enter the existing pond on the west side of the access road.

Nonetheless, a new outlet pipe is necessary from the northwest corner of the facility to the existing downstream ditch to provide a functioning flow control structure for the proposed wetpond.

4.3 Permanent Pool Sizing

The size of a wet pond is dictated by a number of parameters, including:

• Maximum Hydraulic Loading Rate of 2.0 CF/SF/day

• Maximum Outflow Rate for Pollution Control: 2/3 of design daily inflow rate

• Maximum Flow Control Discharge: Pre-Developed 10-year Peak

• Minimum Required Volume = 1/3 of Daily Inflow

The design daily inflow rate is extracted from the treatment event model’s discharge hydrograph and used to calculate required pond parameters as shown in Table 4

Table 4: Wet Pond Water Quality Sizing Parameters

Parameter Definition Value Units

Daily Inflow Volume 𝑉𝑑= Volume from 1.0” Event 112,480 Cubic Feet

Daily Inflow Rate 𝑄𝑑 = 𝑉𝑑

86,400 𝑠𝑒𝑐⁄ 1.30 CFS

Maximum Discharge 𝑄𝑚𝑎𝑥 = 2

3⁄ 𝑄𝑑 0.87 CFS

Minimum Area 𝐴𝑚𝑖𝑛 = 𝑉𝑑

2.0 𝐶𝐹 𝑆𝐹 𝑑𝑎𝑦⁄⁄⁄ 56,240 Square Feet

Minimum Volume 𝑉𝑚𝑖𝑛 = 𝑉𝑑 ∗ (1 3⁄ ) 37,490 Cubic Feet

Minimum Permanent Pool Depth 𝑑𝑝 = 𝑉𝑚𝑖𝑛

𝐴𝑚𝑖𝑛 ⁄ 0.67 Feet

In order to divert all flow from the site into such a facility, a maximum permanent pool invert of about

1,309.30 ft NAVD is required to account for conveyance system slope to the site (as discussed in Section 4.1) and the permanent pool depth beneath the pipe invert discharging to the pond.

4.4 Outlet Structures

Multiple outlets are required for a wetpond facility. An orifice is required at the top of the permanent pool to meter discharge of the treatment event from the pond. One or more secondary discharge pipes, orifices, or notches can be used to provide peak flow control to a minimum of a 10-year level. Finally, an overflow riser is generally needed to discharge 25-year and greater events. A schematic of the wet pond model is provided in

Figure 5.

The SSA model confirms that pond parameters in Table 4 are generally acceptable to provide both treatment and flow control. Outlet facility parameters and peak discharge rates from the model are described in Table 5.

The wet pond at its minimum size provides greater peak attenuation than required.

Table 5: Wet Pond Facility Discharge

Parameter Value Units

Low Flow Orifice Invert 1310.00 Ft NAVD

Low Flow Orifice Diam. 6.00 Inches

Overflow Riser Diam. 18.0 Inches

Riser Elevation 1312.00 Ft NAVD

Treatment Discharge 0.87 CFS

10-year Discharge 7.98 CFS

25-year Discharge 9.11 CFS

Discharge Pipe Diam. 24.0 Inches

Hydrographs extracted from SSA for the wet pond discharge and the pre-developed basin are provided in

Figure 7 through Figure 9.

Figure 7: Pre- and Post-Development Water Quality Event Discharge.

Figure 8: Pre- and Post-Development 10-year Site Discharge.

Figure 9: Pre- and Post-Development 25-year Site Discharge.

Peak water surface elevations occur as shown in Table 6.

Table 6: Wet Pond Facility Maximum Water Surfaces.

Event Water Surface (ft NAVD)

Water Quality 1311.11

10-yr 1313.12

25-yr 1313.35

An excess of detention storage below the rim of the facility is provided, as the depth of the facility is dictated primarily by the depth of the MS4 routing runoff into treatment and storage. There is therefore little concern that an overflow event will occur. However, an emergency overflow will be provided above the peak water surface elevation estimated by the model for the 25-year event.

4.5 Final Facility Dimensions and Access

An existing access road exists along the western boundary of the driving range site, shown in Figure 10. This provides an inherently convenient point of access to both the discharge point to the wet pond and to the orifice, riser, and overflow discharge at the downstream end of the facility.

Figure 10: Former Driving Range Site and Topography.

In order to keep the facility as shallow as possible and minimize excavation and off-haul, keeping the facility as close as possible to the storm system connection and outfall point is preferable. Impacts to the trees adjacent to Avenue N/L should also be avoided, leaving approximately 430 feet from the tree drip line to the northern property line in which to place a pond. Setbacks of at least 20 feet are applied to the property line and the tree line to determine the maximum overall facility length. 70 feet of side slopes (approximately 35 feet on each side) to the top of the permanent pool elevation results in a maximum live storage bottom length of 330 feet. In order to achieve the required bottom area, the pond width would be approximately 170 feet. This provides an initial pond footprint for design purposes.

The RVSQDM requires that a 3:1 aspect ratio be maintained to ensure water quality benefit is provided. The initial dimensions on their own do not meet this criterion. However, use of berms within the pond is allowed to accomplish the minimum required aspect ratio. The pond has been resized to an average length of 260 feet and an average width of 220 feet at the bottom of the dead storage volume (264 ft x 224 ft at the bottom of the detention storage). A berm has been placed laterally in the middle of the facility to accomplish the flow path length shown in Figure 11.

Figure 11: Wet Pond Facility Siting and Layout.

With the facility split approximately in half laterally, the flow path is approximately 570 feet in length, with an average width of 95 feet. The resulting aspect ratio of the bermed pond is about 6:1. This is well in excess of the required aspect ratio, as the length-to-width ratio of the pond footprint is driven by site constraints including avoidance of a gravity conveyance system use for irrigation bypass.

The revised facility dimensions include an additional 2,000 square feet of surface area to account for the berm at the top of the permanent pool (elevation 1310.0). The berm must extend at least to the top of the Water

Quality event peak water surface provided in Table 6. The top of berm elevation will be designed to 1311.5 to provide some freeboard during a water quality event. Larger events will be allowed to overtop the berm and create a level pool between the pond inlet and outlet.

While the maximum bottom of the permanent pool has been determined to be 1309.3, the bottom of the constructed facility will be 1308.3 to provide one foot of sediment storage. This will ensure that the required water quality depth (as determined in Section 4.3) is provided without extremely frequent maintenance to remove accumulated sediment at the bottom of the pond.

4.6 Additional Modeling

An additional model has been developed including the existing capacity in the pond to the west. The 36” discharge pipe conveying runoff to the existing pond facility will remain operational. While the proposed wetpond has been designed without considering its capacity, the existing pond will provide some additional detention storage benefit as long as it remains in place, as well as diverting some discharge from the system into other ponds further to the west at relatively low rates.

The pond has been added to the SSA model with a storage curve derived from the surveyed topography

(Figure 12). The model also includes surveyed overflow weirs and discharge pipes from the pond. These have recorded summer and winter settings, as the overflow weir also includes a gate that can opened or close to alter storage levels in the pond. Because the proposed wetpond has its own flow control structure and discharge system. It is assumed that the gate remains closed, even during the winter to allow the proposed wetpond flow control structure to regulate levels in both ponds. The SSA model schematic in the vicinity of the ponds is shown in Figure 13.

Figure 12: Stage-Area-Storage Curves for the Existing Pond.

Figure 13: SSA Model Including Existing Pond and Design Pipe System.

5,000

10,000

15,000

20,000

25,000

30,000

20,000

40,000

60,000

80,000

100,000

120,000

1309 1310 1311 1312 1313 1314 1315

Su rf ac e

A re a (S

F)

V o lu m e (C

F)

Elevation (ft NAVD)

Volume

Surface Area

Proposed

Wetpond Facility

Existing Pond

Existing Culvert

P ro p o se d

Model results for the Water Quality, 10-year, and 25-year storm event are shown in Figure 14 through Figure

16. These results indicate that with the existing pond remaining in service, capacity is available in the system to provide both water quality and flow control for additional impervious area beyond the existing conditions at the SORCC facilities. In theory, this model could be utilized for future projects to satisfy RVSQDM flow control and treatment requirements by modifying imperviousness of the model’s basins and producing discharge hydrographs. These results would indicate whether the facilities remain compliant with flow control and treatment standards.

Figure 14: Pre- and Post-Development Water Quality Event Site Discharge.

Figure 15: Pre- and Post-Development 10-year Site Discharge.

Figure 16: Pre- and Post-Development 25-year Site Discharge.

4.7 Facility Operations and Maintenance

Operations and Maintenance procedures for the facility are covered in the Project’s separate Operations and

Maintenance Manual (April 2020). Procedures are described for the following facilities associated with the

Wetpond facility:

• General procedures for Vegetated Facilities

• Detention Ponds (covering the “live storage” range in the proposed facility)

• Outlet Control Structures/Flow Restrictors

• Energy Dissipators

• Constructed Wet Ponds

• Access Roads

5 REFERENCES

“Rogue Valley Stormwater Quality Design Manual.” July 2018 (Amended July 2019).

State of Oregon Department of Environmental Quality. “National Pollutant Discharge Elimination System

Municipal Separate Storm Sewer Systems Phase II General Permit.” Issued November 30, 2018 (Effective

March 1, 2019).

Stormwater Planning and Alternatives Analysis

Appendix A Web Soil Survey Map & Report

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 Jackson County Area, Oregon, Parts of Jackson and Klamath Counties

Natural Resources Conservation Service

November 21, 2019

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

Jackson County Area, Oregon, Parts of Jackson and Klamath Counties 6B—Agate-Winlo complex, 0 to 5 percent slopes 151C—Provig-Agate complex, 5 to 15 percent slopes W—Water

Soil Information for All Uses Soil Properties and Qualities

Soil Qualities and Features Hydrologic Soil Group

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

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42° 26' 51'' N

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Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 350 700 1400 2100

Feet 0 100 200 400 600

Meters Map Scale: 1:8,160 if printed on A landscape (11" x 8.5") sheet.

Soil Map may not be valid at this scale.

MAP LEGEND MAP INFORMATION

Area of Interest (AOI) Area of Interest (AOI)

Soils Soil Map Unit Polygons

Soil Map Unit Lines

Soil Map Unit Points

Special Point Features Blowout

Borrow Pit

Clay Spot

Closed Depression

Gravel Pit

Gravelly Spot

Landfill

Lava Flow

Marsh or swamp

Mine or Quarry

Miscellaneous Water

Perennial Water

Rock Outcrop

Saline Spot

Sandy Spot

Severely Eroded Spot

Sinkhole

Slide or Slip

Sodic Spot

Spoil Area

Stony Spot

Very Stony Spot

Wet Spot

Other

Special Line Features

Water Features Streams and Canals

Transportation Rails

Interstate Highways

US Routes

Major Roads

Local Roads

Background Aerial Photography

The soil surveys that comprise your AOI were mapped at 1:20,000.

Warning: Soil Map may not be valid at this scale.

Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale.

Please rely on the bar scale on each map sheet for map measurements.

Source of Map: Natural Resources Conservation Service Web Soil Survey URL:

Coordinate System: Web Mercator (EPSG:3857)

Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: Jackson County Area, Oregon, Parts of Jackson and Klamath Counties Survey Area Data: Version 18, Sep 11, 2019

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

Date(s) aerial images were photographed: Oct 1, 2018—Nov 30, 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.

Map Unit Legend

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

6B Agate-Winlo complex, 0 to 5 percent slopes

247.3 97.7%

151C Provig-Agate complex, 5 to 15 percent slopes

5.6 2.2%

W Water 0.1 0.0%

Totals for Area of Interest 253.0 100.0%

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.

Jackson County Area, Oregon, Parts of Jackson and Klamath Counties

6B—Agate-Winlo complex, 0 to 5 percent slopes

Map Unit Setting National map unit symbol: hrty Elevation: 1,100 to 4,000 feet Mean annual precipitation: 18 to 30 inches Mean annual air temperature: 46 to 54 degrees F Frost-free period: 120 to 180 days Farmland classification: Farmland of statewide importance

Map Unit Composition Agate and similar soils: 55 percent Winlo and similar soils: 35 percent Minor components: 4 percent Estimates are based on observations, descriptions, and transects of the mapunit.

Description of Agate

Setting Landform: Fan terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium derived from igneous, metamorphic and sedimentary rock

Typical profile H1 - 0 to 6 inches: loam H2 - 6 to 25 inches: clay loam H3 - 25 to 30 inches: cemented material H4 - 30 to 62 inches: extremely gravelly coarse sandy loam

Properties and qualities Slope: 0 to 5 percent Depth to restrictive feature: 20 to 30 inches to duripan Natural drainage class: Well drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20 to 0.57 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 4.0 inches)

Interpretive groups Land capability classification (irrigated): 4s Land capability classification (nonirrigated): 4s Hydrologic Soil Group: C Ecological site: BISCUIT-SCABLAND (BISCUIT) 18-26 PZ (R005XY006OR) Forage suitability group: Well Drained < 15% Slopes (G005XY004OR) Hydric soil rating: No

Description of Winlo

Setting Landform: Fan terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium

Typical profile H1 - 0 to 4 inches: very gravelly clay loam H2 - 4 to 9 inches: very gravelly clay H3 - 9 to 17 inches: cemented material H4 - 17 to 60 inches: extremely gravelly coarse sandy loam

Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: 7 to 15 inches to duripan Natural drainage class: Somewhat poorly drained Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: About 0 to 6 inches Frequency of flooding: None Frequency of ponding: Frequent Available water storage in profile: Very low (about 1.0 inches)

Interpretive groups Land capability classification (irrigated): 6s Land capability classification (nonirrigated): 6s Hydrologic Soil Group: D Ecological site: POORLY DRAINED BOTTOM (R005XY016OR) Forage suitability group: Somewhat Poorly Drained < 15% Slopes

(G005XY008OR)

Hydric soil rating: No

Minor Components

Padigan Percent of map unit: 2 percent Landform: Alluvial fans Ecological site: POORLY DRAINED BOTTOM (R005XY016OR) Hydric soil rating: Yes

Cove Percent of map unit: 2 percent Landform: Flood plains Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: POORLY DRAINED BOTTOM (R005XY016OR) Hydric soil rating: Yes

151C—Provig-Agate complex, 5 to 15 percent slopes

Map Unit Setting National map unit symbol: hrp4 Elevation: 1,100 to 4,000 feet Mean annual precipitation: 18 to 30 inches Mean annual air temperature: 46 to 54 degrees F Frost-free period: 120 to 180 days Farmland classification: Farmland of statewide importance

Map Unit Composition Provig and similar soils: 60 percent Agate and similar soils: 30 percent Minor components: 3 percent Estimates are based on observations, descriptions, and transects of the mapunit.

Description of Provig

Setting Landform: Fan terraces Landform position (three-dimensional): Riser Down-slope shape: Linear Across-slope shape: Linear Parent material: Stratified alluvium

Typical profile Oi - 0 to 1 inches: slightly decomposed plant material H1 - 1 to 10 inches: very gravelly loam H2 - 10 to 16 inches: very gravelly clay loam H3 - 16 to 61 inches: stratified extremely gravelly clay loam to extremely gravelly clay

Properties and qualities Slope: 5 to 15 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 4.2 inches)

Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: C Ecological site: LOAMY HILLS 20-35 PZ (R005XY026OR) Forage suitability group: Well Drained < 15% Slopes (G005XY004OR)

Hydric soil rating: No

Description of Agate

Setting Landform: Fan terraces Landform position (three-dimensional): Riser Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium derived from igneous, metamorphic and sedimentary rock

Typical profile H1 - 0 to 6 inches: loam H2 - 6 to 25 inches: clay loam H3 - 25 to 30 inches: cemented material H4 - 30 to 62 inches: extremely gravelly coarse sandy loam

Properties and qualities Slope: 5 to 15 percent Depth to restrictive feature: 20 to 30 inches to duripan Natural drainage class: Well drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20 to 0.57 in/hr) Depth to water table: More than 80 inches…