Attachment_No__6_JOTR_250023_Entrance_Station_100_CD_Stamped_Report_220121.pdf

Percolation Report for New West Entrance Station

Joshua Tree National Park, CA

January 11, 2022

Prepared for:

National Park Service

Joshua Tree National Park

74485 National Park Drive Twentynine Palms, CA 92277-3597

Sarah Raube, Project Manager

Regional Office, San Francisco, CA

Sarah_Raube@nps.gov

Prepared by:

Provost & Pritchard Consulting Group

Clovis, California

G7437

SR106702

COPYRIGHT 2020 by PROVOST & PRITCHARD CONSULTING GROUP

ALL RIGHTS RESERVED

Provost & Pritchard Consulting Group expressly reserves its common law copyright and other applicable property rights to this document. This document is not to be reproduced, changed, or copied in any form or manner whatsoever, nor are they to be assigned to a third party without first obtaining the written permission and consent of Provost & Pritchard Consulting Group In the event of unauthorized reuse of the information contained herein by a third party, the third party shall hold the firm of Provost & Pritchard Consulting Group harmless, and shall bear the cost of Provost & Pritchard Consulting Group legal fees associated with defending and enforcing these rights.

Percolation Report for New West Entrance Station National Park Service i

TABLE OF CONTENTS

1 INTRODUCTION

1.1 Description of Site and Proposal

1.1.1 Notice of Intent to Perform Percolation Testing

1.1.2 Location of Land

1.2 Proposed Development/Project/Land Use

1.2.1 Type of Project

1.2.2 Project Size

1.2.3 Sewage Disposal System

1.2.4 Grading Design

1.3 Description of Site and Surroundings

1.3.1 Topography

1.3.2 Water Courses

1.3.3 Vegetation

1.3.4 Existing Structures

1.3.5 Wells

1.3.6 Rock Outcroppings

1.3.7 Groundwater

1.3.8 NRCS Soil Data

1.4 Equipment

1.4.1 Equipment Used

2 Percolation testing methods and procedures

2.1 Exploratory Borings

2.2 In-situ Percolation Test Pits

2.2.1 Test Procedure

2.2.2 Percolation test results

2.2.3 Discussion of Results

2.2.4 Potential Source of Error

3 Design

3.1 General Criteria

3.1.1 Application Rate

ii

3.1.2 Setback Requirements

3.1.3 Design Wastewater Generation Flowrate

3.1.4 Septic Tank Size

3.2 Leach Line Design

3.2.1 Minimum length required

4 CONCLUSIONS AND RECOMMENDATIONS

APPENDICES

Appendix A Notice of Intent to Perform Percolation Testing

Appendix B Percolation Testing Work Plan

Appendix C Assessor’s Parcel Map

Appendix D NRCS Soil Report

Appendix E Descriptive Soil Logs

Appendix F Field Percolation Test Data

Appendix G Percolation Test Calculations

Appendix H LAMP Setback Requirements Table

Appendix I Alternate Waste Generation Calculation

Appendix J Leach Line Calculation

Appendix K Sanitary Sewer Plot Plan and Details iii

LIST OF TABLES Page

Table 1: Clear Water Percolation Test Rate Results (minutes per inch)

Table 2: Application Rates Assigned from Maximum Percolation Test Rates

Table 3 Actual Septic Tank and Disposal Field Setbacks iv

ABBREVIATIONS

CPC ........................................................................................... California Plumbing Code

EHS .................................................................................. Environmental Health Services

EP ............................................................................................................ Exploratory Pits

JOTR .......................................................................................Joshua Tree National Park

LAMP ...................................................................... Local Agency Management Program

NRCS .............................................................. National Resources Conservation Service

OTWS .................................................................. On-site Wastewater Treatment System

P&P ........................................................................ Provost & Pritchard Consulting Group

TP....................................................................................................... Percolation Test Pit

SECTION 1 Percolation Report for New West Entrance Station

1 INTRODUCTION

The National Park Service is constructing a new West Entrance Station Facility for Joshua Tree National Park. The project will remove the single entrance station kiosk building located approximately 300 feet east from the western park boundary at Quail Springs Road and construct a new West Entrance Station Facility approximately 2,500 feet inside the Park boundary along Park Boulevard. The new entrance station will include the construction of four new entrance station kiosk buildings, a support building, and associated site improvements. The support building will have a single restroom for NPS staff that will work at the facility. This restroom will not open to the public. A new conventional on-site wastewater treatment system (OWTS) consisting of a septic tank with leach line disposal is proposed to support disposal of wastewater that will be generated from the single restroom in the support building. The objective of this report is to present Provost & Pritchard’s exploratory soil borings and in-situ soil percolation testing results and calculations to determine the minimum leach line length required based on completed field testing.

1.1 Description of Site and Proposal

1.1.1 Notice of Intent to Perform Percolation Testing

On October 15, 2020, Provost and Pritchard Consulting Group (P&P) notified the San Bernardino County Public Health Environmental Health Services (EHS) Department via email that P&P would be conducting exploratory soil borings and in-situ percolation tests on-site in JOTR. The submitted email from P&P contained the standard EHS Notice of Intent to Perform Percolation Testing Form as well as a Percolation Testing Work Plan.

The Work Plan illustrated the proposed locations of exploratory borings and in-situ percolation test pits. The Notice of Intent to Perform Percolation Testing Form and Percolation Testing Work Plan are contained in Appendices A and B respectively.

1.1.2 Location of Land

The new West Entrance Station is located along Park Blvd., approximately 2,500 feet inside the National Park Service West Boundary which borders the community of Joshua Tree, CA. This property is identified on the County of San Bernardino’s Assessor’s Parcel Map as parcel 0589-231-33. This assessor parcel map is included in Appendix C. The site is located within Township 1S, Range 7E, and Section 16, more particularly at the coordinates of 34.0901˚ Latitude, -116.2589˚ Longitude.

1.2 Proposed Development/Project/Land Use

1.2.1 Type of Project

The West Entrance Station project is a new site development that will remove the existing single kiosk west entrance station and retain the existing public comfort station restroom that is located approximately 250 feet east of the western park boundary at Quail Springs

Road. The project will construct a new West Entrance Station Facility comprised of four entrance station kiosks, addition of two inbound and outbound lanes, a new support building with a single restroom, and a dedicated parking area for NPS staff that will work at the facility. NPS architectural and engineering consultants are currently preparing construction documents for this new entrance station facility. As part of this effort, P&P is preparing civil engineering construction documents including site demolition, site grading and paving, and site utility plans. The site utility plans include an overall site plan illustrating the entire layout of the new OWTS system as well as construction details for new OWTS system.

1.2.2 Project Size

The total disturbed area for the project is estimated to be approximately 1.5 acres. The new West Entrance Station Kiosks will range in size from 155 sf to 180 sf. The support building is approximately 410 sf.

1.2.3 Sewage Disposal System

The new sewer disposal system will be a conventional OWTS. National Park Service Parks tend to work with limited maintenance funding; therefore, the project will construct two leach field zones: one for the primary leach field and the other as the 100% expansion leach field. The project design will incorporate manual control valves enabling NPS Maintenance staff to control effluent flow between the two leach fields. JOTR Facilities staff will manually operate the valves twice a year to alternate disposal between the primary leach field and 100% expansion leach field.

1.2.4 Grading Design

The proposed grading design for the new entrance station will involve fine grading of the roadway corridor to provide for additional inbound and outbound lanes at the new West Entrance Station. The new leach lines will be installed in native ground, outside the limits of proposed roadway grading area.

1.3 Description of Site and Surroundings

1.3.1 Topography

This portion of the desert has a consistent slope of 4%-6% in a northwesterly direction.

1.3.2 Water Courses

Drainage is generally sheet flow in this portion of the desert. However, there is a localized drainage, tributary to Quail Wash, located approximately 350’ southeast of the proposed leach field area. This drainage passes under Park Blvd. through a pair of two 24” diameter culverts.

1.3.3 Vegetation

The vegetation consists of various species of desert bushes, cacti, and Joshua Trees that are moderately to densely spaced.

1.3.4 Existing Structures

The surrounding area of JOTR is undeveloped open space, with the exception of the existing west entrance station kiosk and comfort station. Both facilities are located approximately 2,500 feet from the New West Entrance Station. The nearest rural residence outside the Park boundary is approximately 2,500 feet from the New West Entrance Station as well. These structures are provided domestic water from the Joshua Basin Water District. The comfort station has an existing OWTS. The proposed OWTS at the New West Entrance Station site will not adversely impact any existing structure’s disposal system.

1.3.5 Wells

There are no active or inactive wells within 600 feet of the proposed effluent disposal area. The domestic water supply for the new West Entrance Station Support Building will be provided by a new 1-1/2” water service that will be extended from the existing JOTR Comfort Station located adjacent the existing west entrance station. This comfort station has an existing water service from Joshua Basin Water District. A booster pump will be installed at the comfort station to boost water pressure for the new West Entrance Station Support Building.

1.3.6 Rock Outcroppings

There were no visible rock outcroppings located within the proposed leach field locations or project site.

1.3.7 Groundwater

According to California Department of Water Resources data, groundwater depth in this general area near the west entrance to Joshua Tree National Park ranged from approximately 60 to 600 feet below the ground surface in Spring of 2018. No groundwater was encountered during excavation of the exploratory borings.

1.3.8 NRCS Soil Data

A National Resources Conservation Service (NRCS) soil report for the project area was reviewed and is included in Appendix D. This report shows the project area soils are mapped as Morongo sand. This soil unit has a typical profile of sand to 28 inches and coarse sand from 28 to 59 inches and is somewhat excessively drained with a moderately high to very high hydraulic conductivity. Depth to restrictive feature is reported as more than 80 inches. These soils are generally desirable characteristics for leach fields.

1.4 Equipment

1.4.1 Equipment Used

John Deere 310J backhoe with 24” bucket

Hand trowel

Tape measure with 0.1’ divisions

48” T-bar soil probe

4” diameter hand auger

12” lengths of 4” diameter slotted PVC

Pea gravel

5-gallon water containers

Stopwatch

Ruler with 1/8” divisions

SECTION 2 Percolation Report for New West Entrance Station

2 PERCOLATION TESTING METHODS AND PROCEDURES

In accordance with the work plan, previously mentioned in Section 1.1.1, NPS staff provided the John Deere 310J backhoe to excavate the exploratory borings and in-situ percolation test pits. A P&P geologist supervised the excavations, classified soils by the Unified Soil Classification System, and conducted percolation testing. A total of 5 exploratory pits (EP-1 to EP-5) and 4 percolation test pits (TP-1 to TP-4) were excavated.

A site map which illustrates the locations of the exploratory pits and percolation test pits is included in Appendix B. Soils were classified from within the pit up to approximately 4 to 4 ½ feet depth. Soils excavated deeper than 4 feet were logged from cuttings from the backhoe bucket. Resulting pits were typically 2 feet wide and 9 to 18 feet long. Exploratory pits met practical backhoe refusal between 3.7 and 8.9 feet. Percolation test pits had target depths of 2 feet or 4 feet which were reached in each pit.

2.1 Exploratory Borings

Soils encountered during field work were fairly consistent across the project area, with the exception of EP-5. Textures encountered were primarily silty sand, sand with silt, and sand. Some components of clay were observed below 6 feet in EP-3 and EP-4 and from

1.7 to 5.5 feet in EP-5. The top 1 to 2 feet of soil was generally loose to medium density with some weak structure. Below 2 feet was generally medium dense to dense with no structure. Dense to very dense, moderately to strongly cemented soils were typically encountered between 5 and 8 feet and caused practical backhoe refusal above 9 feet.

These dense, cemented soils were generally encountered deeper on the southwest side of Park Boulevard, further away from the road. In EP-5 backhoe refusal was met in a dense clayey sand at 3.7 feet, so a hand auger was used to excavate from the bottom of the pit to 7.5 feet. Because of the dense soils encountered and few areas of clayey soils, the soils in the project area are considered moderate as defined in the San Bernardino County Percolation Testing and Reporting Standards. The descriptive logs of the five exploratory boring pits and 4 percolation test pits are attached in Appendix E.

No groundwater, saturated soils, or seepage was encountered. The soils were observed for evidence of seasonally high ground water such as characteristic vegetation, oxidation mottles, blackened zones, or pockets of residual saturation. To the depth of exploration there appeared to be no evidence of seasonal high groundwater. Bedrock was not encountered in the pits.

2.2 In-situ Percolation Test Pits

2.2.1 Test Procedure

The four in-situ percolation tests were performed in general accordance with the San Bernardino County Percolation Testing and Reporting Standards. Test pits were excavated with the backhoe to depths of 4.2, 2.9, 4.2, and 2.7 feet, respectively for TP-1 to TP-4. A 4-inch diameter hand auger was used to dig a 13-inch-deep boring at the bottom of each pit. The boring was then widened to approximately 5 ½ inches with a hand trowel. Approximately 2 inches of pea gravel was placed in the bottom of each boring. A 12-inch length of 4-inch diameter perforated PVC pipe was placed in each boring to prevent sloughing of the sandy soils. A 5-gallon container of water was inverted into each boring to allow pre-soaking on the evening of October 20. On October 21, each 5-gallon container was empty and the soils were visibly saturated. TP-2, TP-3, and TP-4 had fine sandy material on top of the gravel, so the materials were scraped out and replaced with 2 inches of clean gravel.

Percolation testing was conducted on the afternoon of October 21. Water was poured into the test holes to provide several inches of water above the gravel. Measurements of the water depth were taken from the top of the PVC pipe. Measurements were generally taken when the water had fallen between 1 and 3 inches. Additional water was placed in the test holes after several inches of water had percolated.

2.2.2 Percolation test results

All percolation testing data and calculations have been provided in Appendices F and G accordingly. The resulting percolation rates calculated from the tests are summarized in Table 1 below.

Table 1: Clear Water Percolation Test Rate Results (minutes per inch)

Test Pit Minimum Maximum Mean

TP-1 0.3 6.5 2.8

TP-2 1.9 3.9 2.6

TP-3 5.0 14.0 11.1

TP-4 1.7 3.3 2.2

Application rates are assigned based on the Table in Section 4.5 of the San Bernardino County Percolation Testing and Reporting Standards. The associated application rates utilizing the most conservative percolation rate from each test are shown in Table 2 below.

Table 2: Application Rates Assigned from Maximum Percolation Test Rates

Test Pit Percolation

Rate (min/in) County Application Rate (gal/day/ft2)

County Application Rate(ft2/gal/day)

TP-1 6.5 0.8 1.25

TP-2 3.9 1.2 0.83

TP-3 14.0 0.743 1.35

TP-4 3.3 1.2 0.83

2.2.3 Discussion of Results

Soils encountered during field work were fairly consistent across the project area and are considered moderate as defined in the San Bernardino County Percolation Testing and Reporting Standards. However, the range of percolation rates calculated is not considered uniform by the San Bernardino Percolation Testing and Reporting Standards.

The slowest rate of percolation was observed in TP-3. This pit had the highest apparent density of the test pits and was excavated to just above the depth that cemented soils began in the nearest exploratory pit, EP-4. Despite being the slowest test, the resulting percolation rate is still favorable for water disposal. This indicates that the dense sandy soils encountered in the project area are not impermeable.

2.2.4 Potential Source of Error

Each test was conducted in similar, yet not identical textured soils. The varying soil densities likely had some effect on the variability of the test results.

SECTION 3 Percolation Report for New West Entrance Station

3 DESIGN

3.1 General Criteria

As previously mentioned in the Section 1.2.3, this project will be utilizing a conventional on-site wastewater treatment system. In order to calculate the length of leach lines needed, various parameters needed to be determined.

3.1.1 Application Rate

The first parameter to be determined is the application rate. The percolation test results illustrated that the test pit soil did not have uniform percolation rates. Per San Bernardino County’s Percolation Testing and Reporting Standards, when soils do not have uniform percolation rates, the most conservative application rate must be used. In consideration of the percolation rate and application rates identified in Table 2, this equated to 1.35 ft2/gal/day as the project application rate.

3.1.2 Setback Requirements

The next parameter to be determined are project setbacks. Given that the surrounding area of JOTR is open space, setbacks to adjacent buildings and infrastructure facilities will greatly exceed minimum County standards. San Bernardino County provides specific setback requirements within their Local Agency Management Program (LAMP) document. This project follows the guidelines that are set forth within table 3.1 of the LAMP document, which is included in Appendix H. With that said the following setbacks have been calculated from the proposed location of the OWTS.

Table 3 Actual Septic Tank and Disposal Field Setbacks

Setbacks from Septic Tank Disposal field

Required Provided Required Provided

Buildings or structures 5 25 8 50

Drainage Course 50 410 50 380

Disposal Field 5 25 N/A N/A

Private Domestic Water line

5 20 5 50

Distribution box N/A 22 5 5

Groundwater 5 40’ min 5 40’ min

Earth Cover 1 2’ min 1 2’ min

3.1.3 Design Wastewater Generation Flowrate

The next parameter to be determined is the anticipated wastewater generation (design flowrate) from the Support Building restroom. The San Bernardino County’s Percolation Testing and Reporting Standards states that the wastewater generation rate in terms of gallons per day should be calculated per the most current edition of the California Plumbing Code (CPC). After careful review of the code, it was determined that the CPC does not provide appropriate guidance for maximum daily wastewater generation from a unique private restroom facility as proposed.

The alternate approach to wastewater generation was based on a conservative estimation of total daily use of the restroom. The new Support Building has a single restroom with one toilet and one lavatory that will only be utilized by National Park Service Staff while working at the new West Entrance Station Facility. JOTR experiences a wide variance in visitation, and therefore staffing at the West Entrance Station varies depending on the day and season. The wastewater generation estimate is based on a peak visitation day where JOTR could assign a total of 12 fee collection staff members and 2 law enforcement officers assigned to this location. The wastewater generation estimate projects that each staff member will use the restroom facility 6 times per 8-hour shift. This equates to 84 uses per peak day and yield a wastewater generation value of 155 gallons per day. The calculations also include an additional 50% factor of safety to provide for any unforeseen peak generation of wastewater, which yielded a final daily generation estimate of 233 gallons per day. A copy of the wastewater generation calculations is included in Appendix H.

3.1.4 Septic Tank Size

The final parameter to be determined was the septic tank size. As this project will only provide one toilet and one sink the project fell into the least impactful category of a residential home 1-2 bedrooms. Per the LAMP document, the minimum septic tank capacity shall be 750 gallons for a site that is considered to be a single-family residence with 1-2 bedrooms.

3.2 Leach Line Design

3.2.1 Minimum length required

With the parameters calculated in the previous section, the following equation was used to determine the minimum leach line length required:

LL =

Where, LL=Leach Line Length (ft)

Aa=Absorption Area (sf)

Ta=Trench Area (ft)

The Trench Area was determined to be 7 ft based on the recommendations outlined in the LAMP document. The project will incorporate a typical rock filled leach line trench that will be 3 feet wide with 2-foot-deep side walls underneath the perforated leach line.

The Absorption Area was calculated from the following equation:

Aa=PR x WG

Where, Aa=Absorption Area (sf)

PR=Percolation Rate (sf/gal/day)

WG=Wastewater Generation (gal/day)

Utilizing the equation to calculate the leach line length, the minimum leach line length was determined to be 45 ft. This calculation is included in the Appendix J.

SECTION 4 Percolation Report for New West Entrance Station

4 CONCLUSIONS AND RECOMMENDATIONS

The approach by the National Park Service is to apply conservatism to the wastewater disposal design and construction. Additionally, the project will construct the secondary (100% expansion) disposal field concurrent with the primary disposal field. The calculations for application area are consistent with County of San Bernardino EHS standards and use the most conservative percolation rate observed through field testing of 4 test pits. Wastewater generation estimates are based a conservative assumption of peak day staffing of the West Entrance Station and include an additional 50% factor of safety.

P&P recommends that the primary and secondary disposal fields each provide a minimum of 50 linear feet of leach line, constructed in two, 25’ long increments.

Appendix A Notice of Intent to Perform Percolation Testing

Public Health Environmental Health Services

PERCOLATION TEST NOTIFICATION

www.SBCounty.gov www.sbcounty.gov/dph/dehs

Phone: (800) 442-2283

Page 1 of 1 May 2015

Please email form to EHSPlanReview@gmail.com or fax to 909.387.4323 at least two (2) working days before testing.

THIS SECTION TO BE COMPLETED BY QUALIFIED PROFESSIONAL

QUALIFIED PROFESSIONAL INFORMATION

Firm Name

Provost & Pritchard Consulting Group Date

10/15/20 Firm Address

286 W. Cromwell Ave.

City

Fresno State

CA

Zip

93711 Firm Contact Person

Soo Ho Park Email(s) spark@ppeng.com Phone Number

(559) 449-2700

SITE INFORMATION

Owner’s Name

United States of America Assessor’s Parcel Number (APN)

0589-231-33-0000 Site Address

City

State

CA

Zip

Email(s)

Phone Number

BILLING INFORMATION

Environmental Health Services may need to be onsite to observe percolation testing. This will be billed at the current hourly professional rate. Provide billing information below or check one of the following:

Same as Qualified Professional Information Same as Site Information

Billing Name

Billing Address

City

State

Zip

Email(s)

Phone Number

PROJECT INFORMATION

Disposal field Leach Lines Seepage Pits Alternative Treatment System

Exploratory Boring(s)

Boring Date(s)

10/20, 10/21 Boring Time

8am Number of Borings

Depth of Boring(s) in ft.

10-12

Testing Test Date(s)

10/20, 10/21 Test Time

8am Number of Tests

Depth of Test Hole(s) in ft.

2 @ 2'; 2 @ 4'

Project Type

Single Family Residence Multi Family Residential Commercial

Lot Size (ft2/acres)

Number of Units

N/A

Estimated Flow

140gpd

Please select one of the following

Tentative Tract (TT) # Tentative Parcel Map (TPM) #

Number of Proposed Lots

Original Lot Size (ft2/acres)

Average New Lot Size (ft2/acres)

A sewer connection will be required if a sewer is available within 200 ft. of the nearest property line (add 100 ft. for each additional lot).

A “sewer will not serve” letter may be required prior to submittal of the percolation report.

Site Conditions

Historic groundwater level in feet >10' Slope in disposal area (%) 5

Source of Water

Private Well Water Purveyor

Check box if parcel is on Forest Service Land

Check box if lot is within 100 feet of a river/stream

For Office Use Only For Office Use Only For Office Use Only For Office Use Only For Office Use Only Fee:

FA Number:

Record ID:

PE Number:

Late Fee: Y N Designated Employee:

Received By:

Date:

Check One: New Transfer Reactivate Changes (please specify):

The project is located 2,500' southeasterly of Joshua Tree National Parks westerly boundary at Quail Springs Road 34°05'26.7"N, 116°15'33.6"W http://www.sbcounty.gov/dph/dehs http://www.sbcounty.gov/dph/dehs mailto:EHSPlanReview@gmail.com

Appendix B Percolation Testing Work Plan

Legend

Exploratory Borings (Soil Log Test Pits)

Percolation Test Pits

BEGINNING CURVE OF

ASPHALT PULLOUT100'±

100'±

100'± B A

Percolation test pits offset 5' minimum from Exploratory Pits, TYP

5' M

IN

EP5

TP-4

EP-4

TP-3

EP3

EP2

TP-1

EP-1 TP-2

Appendix C Assessor’s Parcel Map

Appendix D NRCS Soil Report

Soil Map—Joshua Tree National Park, California (Joshua Tre National Park)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

6/12/2018

567700 567800 567900 568000 568100 568200 568300 568400 568500 568600 568700

567700 567800 567900 568000 568100 568200 568300 568400 568500 568600 568700

34° 5' 42'' N

6°

5'

9' ' W

34° 5' 42'' N

6°

5'

7'

' W

34° 5' 19'' N

6°

5'

9'

' W

34° 5' 19'' N

6°

5'

7'

' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 200 400 800 1200

Feet 0 50 100 200 300

Meters Map Scale: 1:4,950 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 1:24,000.

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: Joshua Tree National Park, California Survey Area Data: Version 7, Sep 11, 2017

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

Date(s) aerial images were photographed: May 5, 2010—May 16, 2010

The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

Soil Map—Joshua Tree National Park, California (Joshua Tre National Park)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

6/12/2018

Map Unit Legend

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

3677 Morongo sand, 2 to 4 percent slopes

117.7 94.7%

4804 Rock outcrop-Ironped-Pinecity association, 30 to 60 percent slopes

6.6 5.3%

Totals for Area of Interest 124.3 100.0%

Soil Map—Joshua Tree National Park, California Joshua Tre National Park

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

6/12/2018

Map Unit Description

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 in this report, 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, soils that are similar to the named components, and some minor components that differ in use and management from the major soils.

Most of the soils similar to the major components 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. Some minor components, however, have properties and behavior 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.

Map Unit Description: Morongo sand, 2 to 4 percent slopes---Joshua Tree National Park, California

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

5/29/2018

Soils that have profiles that are almost alike make up a soil series. All the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of a given 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.

Additional information about the map units described in this report is available in other soil reports, which give properties of the soils and the limitations, capabilities, and potentials for many uses. Also, the narratives that accompany the soil reports define some of the properties included in the map unit descriptions.

Joshua Tree National Park, California

3677—Morongo sand, 2 to 4 percent slopes

Map Unit Setting National map unit symbol: 2m7t2 Elevation: 3,300 to 3,800 feet Mean annual precipitation: 4 to 7 inches Mean annual air temperature: 55 to 68 degrees F Frost-free period: 210 to 320 days

Map Unit Description: Morongo sand, 2 to 4 percent slopes---Joshua Tree National Park, California

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Farmland classification: Not prime farmland

Map Unit Composition Morongo and similar soils: 80 percent Minor components: 20 percent Estimates are based on observations, descriptions, and transects of the mapunit.

Description of Morongo

Setting Landform: Fan aprons Landform position (two-dimensional): Backslope Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium derived from granitoid

Typical profile A - 0 to 1 inches: sand Bw - 1 to 6 inches: sand C1 - 6 to 28 inches: sand C2 - 28 to 59 inches: coarse sand

Properties and qualities Slope: 2 to 4 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat excessively drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat):

Moderately high to very high (1.42 to 14.17 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 1 percent Available water storage in profile: Low (about 3.5 inches)

Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7s Hydrologic Soil Group: A Ecological site: Desert Fans 4-6 P.Z. (R030XB005NV) Hydric soil rating: No

Minor Components

Morongo, very rarely flooded Percent of map unit: 8 percent Landform: Fan aprons Landform position (two-dimensional): Backslope Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: Sandy Fan Aprons (R030XB174CA)

Map Unit Description: Morongo sand, 2 to 4 percent slopes---Joshua Tree National Park, California

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Hydric soil rating: No

Jumborox, warm Percent of map unit: 5 percent Landform: Fan remnants Landform position (two-dimensional): Summit, backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across-slope shape: Convex Ecological site: Loamy Very Deep Fan Remnants correlated to

R030XB009CA (R030XB183CA)

Hydric soil rating: No

Ambrosia Percent of map unit: 5 percent Landform: Fan aprons Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across-slope shape: Linear Ecological site: Desert Fans 4-6 P.Z. (R030XB005NV) Hydric soil rating: No

Morongo, rarely flooded Percent of map unit: 2 percent Landform: Drainageways Landform position (two-dimensional): Backslope Down-slope shape: Linear Across-slope shape: Linear Ecological site: Rarely Flooded Warm Thermic Ephemeral System copied to XB187 (R030XY187CA) Hydric soil rating: No

Data Source Information

Soil Survey Area: Joshua Tree National Park, California Survey Area Data: Version 7, Sep 11, 2017

Map Unit Description: Morongo sand, 2 to 4 percent slopes---Joshua Tree National Park, California

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Map Unit Description

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 in this report, 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, soils that are similar to the named components, and some minor components that differ in use and management from the major soils.

Most of the soils similar to the major components 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. Some minor components, however, have properties and behavior 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.

Map Unit Description: Rock outcrop-Ironped-Pinecity association, 30 to 60 percent slopes--- Joshua Tree National Park, California

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Soils that have profiles that are almost alike make up a soil series. All the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of a given 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.

Additional information about the map units described in this report is available in other soil reports, which give properties of the soils and the limitations, capabilities, and potentials for many uses. Also, the narratives that accompany the soil reports define some of the properties included in the map unit descriptions.

Joshua Tree National Park, California

4804—Rock outcrop-Ironped-Pinecity association, 30 to 60 percent slopes

Map Unit Setting National map unit symbol: 223kp Elevation: 2,950 to 4,620 feet Mean annual precipitation: 4 to 7 inches Mean annual air temperature: 55 to 68 degrees F

Map Unit Description: Rock outcrop-Ironped-Pinecity association, 30 to 60 percent slopes--- Joshua Tree National Park, California

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Frost-free period: 210 to 320 days Farmland classification: Not prime farmland

Map Unit Composition Rock outcrop: 45 percent Ironped and similar soils: 25 percent Pinecity and similar soils: 20 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit.

Description of Rock Outcrop

Setting Landform: Hills Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across-slope shape: Linear

Description of Ironped

Setting Landform: Hills Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across-slope shape: Linear Parent material: Residuum weathered from granite

Typical profile A - 0 to 2 inches: gravelly loamy sand Cr - 2 to 59 inches: bedrock

Properties and qualities Slope: 30 to 60 percent Depth to restrictive feature: 2 to 14 inches to paralithic bedrock Natural drainage class: Somewhat excessively drained Runoff class: Very high Capacity of the most limiting layer to transmit water (Ksat):

Moderately low to moderately high (0.14 to 1.42 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 1 percent Available water storage in profile: Very low (about 0.1 inches)

Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 8 Hydrologic Soil Group: D Ecological site: Warm Gravelly Shallow Hills (R030XB172CA) Hydric soil rating: No

Map Unit Description: Rock outcrop-Ironped-Pinecity association, 30 to 60 percent slopes--- Joshua Tree National Park, California

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Description of Pinecity

Setting Landform: Hills Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across-slope shape: Linear Parent material: Colluvium derived from granite over residuum weathered from granite

Typical profile A - 0 to 1 inches: gravelly loamy sand Bw - 1 to 6 inches: gravelly loamy sand Cr - 6 to 59 inches: bedrock

Properties and qualities Slope: 30 to 50 percent Percent of area covered with surface fragments: 3.0 percent Depth to restrictive feature: 2 to 14 inches to paralithic bedrock Natural drainage class: Somewhat excessively drained Runoff class: Very high Capacity of the most limiting layer to transmit water (Ksat):

Moderately low (0.01 to 0.14 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 1 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 4.0 Available water storage in profile: Very low (about 0.4 inches)

Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 8 Hydrologic Soil Group: D Ecological site: Shallow Cool Hills (R030XB189CA) Hydric soil rating: No

Minor Components

Littlefargo Percent of map unit: 5 percent Landform: Hills Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Linear Across-slope shape: Linear Ecological site: Shallow Cool Hills (R030XB189CA) Hydric soil rating: No

Map Unit Description: Rock outcrop-Ironped-Pinecity association, 30 to 60 percent slopes--- Joshua Tree National Park, California

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Arizo, occasionally flooded Percent of map unit: 3 percent Landform: Drainageways Landform position (two-dimensional): Backslope Landform position (three-dimensional): Interfluve Down-slope shape: Concave Across-slope shape: Concave Ecological site: Mid Size Thermic To Hyperthermic Ephemeral

Stream copied to XB186 (R030XY186CA) Hydric soil rating: No

Pinecity, cool Percent of map unit: 2 percent Landform: Hills Landform position (two-dimensional): Shoulder Landform position (three-dimensional): Head slope Down-slope shape: Linear Across-slope shape: Linear Ecological site: Bouldery Very Shallow To Shallow Gravelly Slopes

(R030XB170CA)

Hydric soil rating: No

Data Source Information

Soil Survey Area: Joshua Tree National Park, California Survey Area Data: Version 7, Sep 11, 2017

Map Unit Description: Rock outcrop-Ironped-Pinecity association, 30 to 60 percent slopes--- Joshua Tree National Park, California

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Appendix E Descriptive Soil Logs

Appendix F Field Percolation Test Data

Appendix G Percolation Test Calculations

Percolation Test for New Leachfield Joshua Tree National Park Test Pit 1 Date of test: 10/21/2020 Depth of test: 5.5' Pipe length: 12" Soil texture: Silty sand / sand with silt Presoaked: 10/20/2020 Tested by: Darylyn Tachella Hole diameter: 5.5"Pipe diameter: 4" Apparent density:…