United States Gypsum Company Expansion/Modernization Project Imperial County, California

UNITED STATES GYPSUM COMPANY EXPANSION/MODERNIZATION PROJECT IMPERIAL COUNTY, CALIFORNIA

DRAFT SUPPLEMENTAL ENVIRONMENTAL IMPACT STATEMENT DOI-BLM-CA-D070-2018-0049-EIS

Lead Agency: U.S. Bureau of Land Management El Centro Field Office, BLM 1661 S. 4th Street El Centro, CA 92243 In Cooperation With: U.S. Army Corps of Engineers Los Angeles District, Regulatory Division 5900 La Place Ct., Suite 100 Carlsbad, CA 92008-8832

U.S. Environmental Protection Agency Estimated Lead Agency Total Region 9 Costs Associated with Developing 75 Hawthorne Street And Producing This Supplemental EIS San Francisco, CA 94105

$268,250.00 JULY 2019 El Centro Field Office United States Gypsum Company (USG) Expansion Modernization Project Draft Supplemental Environmental Impact Statement to the 2006 Draft and 2008 Final Environmental Impact Report/Environmental Impact Statement (EIR/EIS) for the United States Gypsum Company (USG) Expansion/Modernization Project. Proposed Right-of- Way (ROW) Grant CACA-044014 and CACA-056908 and Plan of Operations (POO)

Lead Agency: Bureau of Land Management (BLM) El Centro Field Office 1661 S 4th St, El Centro, CA 92243

ABSTRACT

The El Centro Field Office of the BLM has prepared this Draft Supplemental Environmental Impact Statement (Draft Supplemental EIS) supplementing the 2006 Draft and 2008 Final Environmental Impact Report/Environmental Impact Statement (EIR/EIS) for the United States Gypsum Company (USG) Expansion/Modernization Project. The 2006 Draft and 2008 Final EIR/EIS evaluated the proposed expansion and modernization of USG’s manufacturing facilities at its Plaster City Plant (Plant) and gypsum quarrying operations at its Plaster City Quarry (Quarry). This supplement considers the Proposed Action and seven alternatives, including a No Action alternative; it includes new alternatives, new information related to threatened and endangered species, and new circumstances or new information related to the federal aspects of the Proposed Action.

The BLM and the USACE will use this document in their consideration of land use and other federal decisions associated with the project. The BLM is the Lead Agency for this environmental review and the USACE is a Cooperating Agency. The U.S. Environmental Protection Agency (USEPA) has the authority to review projects requiring a Clean Water Act (CWA) Section 404 permit; USEPA Region 9 joins as a Cooperating Agency but does not have a direct permitting role in the project.

USG owns and operates a gypsum quarry and processing plant in Imperial County, California. USG’s Quarry holdings total approximately 2,105 acres, of which 2,032 acres are owned by USG and 73 acres are active unpatented mineral claims under BLM jurisdiction.

Previously, USG proposed an expansion and modernization of its Plaster City Plant and Quarry facilities. This proposal included replacing an existing 8-inch diameter water pipeline from USG’s wells in Ocotillo to the Plant, installing an approximately 14.4 megawatt (MW) cogeneration unit for the Plant operation, and constructing an off-specification material recycling system. In December 2001 and May 2002, Imperial County published the Notice of Preparation of the joint EIR/EIS for the USG Project. The BLM published a Notice of Intent (NOI) to prepare a joint EIR/EIS in the Federal Register on May 1, 2002 (Federal Register/Vol. 67, No. 84, p 21713). Subsequent Federal Register notice publications included a Notice of Availability (NOA) for the United States Gypsum Company Expansion/Modernization Project Draft Environmental Impact Report/Environmental Impact Statement on April 21, 2006 (Federal Register/Vol. 71, No. 77, p 20660) and a Notice of Availability (NOA) for the Final EIR/EIS (Federal Register/Vol. 73, No. 51, p 13918). In 2008 the BLM initiated Endangered Species Act (ESA) consultation with United States Fish and Wildlife Service (USFWS). The BLM and the USFWS did not complete the ESA Section 7 Consultation, and the BLM did not issue a Record of Decision (ROD).

The 2008 Final EIR/EIS determined that under baseline conditions (i.e., no increase in water usage by U.S. Gypsum above the average 347 AF per year), water levels in the Basin would decline by up to 10 feet over the next 80 years. With the project, the Final EIR/EIS estimated that the drawdown within the alluvial aquifer after 80 years of pumping would be approximately 30 feet. The Final EIR/EIS noted that this drawdown could potentially lower the water level in some wells, and that if the water level in a particular well were to drop to near the base of the screened interval, the ability to maintain current pumping rates at that well could potentially be reduced. Two Mitigation Measures were presented to reduce the level of significance of identified impacts on groundwater levels and groundwater quality. After the County released the 2008 Final EIR/EIS the Imperial County Board of Supervisors certified the EIR/EIS, adopting findings of fact, a statement of overriding consideration, and a mitigation monitoring program in compliance with CEQA. The County Board of Supervisors filed a Notice of Determination on March 19, 2008.

In 2014 USG requested the BLM issue a Record of Decision on the project. The BLM determined that the project conformed to the applicable land use plan. However, USG would not be able to obtain its regulatory permits from the USACE because the BLM did not issue a Record of Decision for the Final EIR/EIS, and because the USACE did not participate in the original NEPA process as a cooperating agency. A supplemental EIS with the USACE participating as a cooperating agency would be necessary. In 2016, the BLM amended its California Desert Conservation Area (CDCA) Plan, which further contributed to the need for a supplement. The regulations (40 CFR Section 1502.9 (c)(1)) and (c)(4)) state that agencies shall prepare supplements to either draft or final environmental impact statements if: i) the agency makes substantial changes in the proposed action that are relevant to environmental concerns; or ii) there are significant new circumstances or information relevant to environmental concerns and bearing on the proposed action or its impacts. 40 CFR Section 1502.9 (c)(4)) states that agencies shall prepare, circulate, and file a supplement to a statement in the same fashion (exclusive of scoping) as a draft and final statement unless alternative procedures are approved by the Council on Environmental Quality. The USACE intends to adopt this Supplemental EIS to support its decision regarding USG’s CWA Section 404 Permit application.

The BLM’s purpose and need for the Proposed Action is to respond to USG’s request for two right-of-way applications and a decision regarding its revised Plan of Operations. The BLM is required under the General Mining Law of 1872 and the Federal Land Policy and Management Act of 1976, as amended (FLPMA) to respond to an applicant's requests for right-of-way authorizations on BLM lands and for approval of the quarry Plan of Operations.

Decisions to be made:

 Authorize, grant with modifications, or deny USG’s application for a right-of-way for its Ocotillo Water Pipeline Replacement (Case file number CACA 044014)  Authorize, grant with modifications, or deny USG’s application for a right-of-way for its Quarry Pipeline and Electric Transmission Alignment (Case file number CACA 056908)  Approve, approve with conditions, or deny USG Quarry Plan of Operations

The Field Manager of the BLM El Centro Field Office has the authority for site management of future activities related to the ROW Grant requests, Plan of Operation and is the BLM Authorized Officer for this Draft Supplemental EIS.

United States Department of the Interior BUREAU OF LAND MANAGEMENT El Centro Field Office 1661 S. 4th Street El Centro, CA 92243 www.blm.gov/california

July 2019

Dear Reader:

I am pleased to announce the availability of the Draft Supplemental Environmental Impact Statement (Draft Supplemental EIS) to the United States Gypsum Company Expansion/Modernization Project 2006 Draft Environmental Impact Report/Environmental Impact Statement (EIR/EIS), and 2008 Final EIR/EIS. In December 2001, Imperial County published the Notice of Preparation of the joint Environmental Impact Report/Environmental Impact Statement (EIR/EIS) for the United States Gypsum Company Expansion/Modernization Project in compliance with the California Environmental Quality Act (CEQA). As the Lead Agency for the project under the National Environmental Policy Act (NEPA), the Bureau of Land Management (BLM) issued a Notice of Intent (NOI) to prepare a joint EIR/EIS in the Federal Register on May 1, 2002. The Draft EIR/EIS was prepared for the project and was circulated for comment by the public and other interested agencies from April through July of 2006. The BLM also initiated an Endangered Species Act (ESA) Section 7 Consultation with the U.S. Fish and Wildlife Service (USFWS). The Final EIR/EIS was released in January of 2008.

On March 18, 2008 the Imperial County Board of Supervisors certified the EIR/EIS, adopted Findings of Fact, a Statement of Overriding Considerations, and a Mitigation Monitoring Program in compliance with CEQA, and filed a Notice of Determination on March 19, 2008. On March 14, 2008 the BLM published in the Federal Register the Notice of Availability (NOA) of the U.S. Gypsum Company Expansion/Modernization Project Final EIR/EIS. The BLM did not issue a Record of Decision (ROD) pending completion of its ESA Section 7 Consultation.

In 2014, U.S. Gypsum Company (USG) applied to the U.S. Army Corps of Engineers (USACE) for a Clean Water Act (CWA) Section 404 permit for the expanded quarry impacts on “waters of the United States”. The USACE was not a Cooperating Agency in the development of the 2006 Draft EIR/EIS or the 2008 Final EIR/EIS documents.

Subsequent consultation between the BLM and USACE in 2015 led to the determination that a Supplemental EIS must be prepared in order to analyze new information and changes to the Proposed Action that have occurred since the release of the 2008 Final EIR/EIS. The Supplemental EIS will provide the BLM and USACE with a basis for rational decision–making and give the public and other agencies an opportunity to review and comment on the analysis of the new information and/or changes.

July 2019 Page 2

The Draft Supplemental EIS has been prepared in accordance with NEPA and the Federal Land Policy and Management Act (FLPMA), which establishes the land management authority of the BLM. The Supplemental EIS analyses are limited to the following proposed federal actions:

 BLM to approve the USG Quarry Plan of Operations (April, 2018)  BLM to grant Right-of-Way (ROW) CACA 056908 for USG Quarry Pipeline and Transmission Alignment  BLM to grant ROW CACA 044014 for USG Ocotillo Water Pipeline Replacement  USACE to issue required permits under the CWA (Section 404 33 USC 1344) for 2008 USG Expansion/Modernization Project

The Draft Supplemental EIS will be circulated for public review and comment for 45 days from the date the U.S. Environmental Protection Agency publishes the NOA in the Federal Register. All comments must be postmarked or electronically time stamped no later than 45 days from the NOA publication date.

You may submit comments on issues related to the Draft Supplemental EIS by any of the following methods:

 Web site: https://bit.ly/2QiGK0m  Email: [email protected]  Fax: 1-541-618-2400  U.S. Mail or courier: Ms. Miriam Liberatore, Project Manager Bureau of Land Management 3040 Biddle Road Medford, OR 97524

For further information, contact Miriam Liberatore, Project Manager, by email at [email protected] or by phone at 541-618-2412, or by mail at the address above.

Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 1-800-877-8339 to contact the above individual during normal business hours. The FIRS is available 24 hours a day, 7 days a week, to leave a message or questions with the above individual. You will receive a reply during normal business hours.

Before including your address, phone number, e-mail address, or other personal identifying information in your protest, you should be aware that the BLM may make your entire comment—including your personal identifying information—publicly available at any time. While you may include in your comment a request for the BLM to withhold your personal identifying information from public review, we cannot guarantee that we will be able to do so. TABLE OF CONTENTS USG SUPPLEMENTAL DRAFT EIS

Cover Sheet Abstract Dear Reader Letter Table of Contents Acronyms PAGE

Chapter 1 - Introduction ...... 1-1 1.1 Supplemental EIS Purpose and Use ...... 1-1 1.1.1 Background ...... 1-1 1.1.2 Supplemental EIS Scope ...... 1-3 1.1.3 BLM Purpose and Need ...... 1-4 1.1.4 USACE Draft Section 404(b)(1) Alternatives Analysis Basic and Overall Project Purpose and Need ...... 1-4 1.1.5 Applicant’s Objectives ...... 1-5 1.2 General Location and Map ...... 1-5 1.3 Major Authorizing Laws and Regulations ...... 1-6 1.3.1 Bureau of Land Management...... 1-6 1.3.2 U.S. Army Corps of Engineers ...... 1-6 1.4 Relationship to Statutes, Policies, and Plans ...... 1-6 1.4.1 Federal Statutes, Policies, and Plans ...... 1-6 1.4.2 State and Local Laws, Plans, Policies, and Programs ...... 1-8 1.4.3 List of Required Permits and Approvals ...... 1-9 1.5 Document Organization ...... 1-9 1.6 Issues to be Addressed ...... 1-10

Chapter 2 - Proposed Action and Alternatives ...... 2-1 2.1 Introduction ...... 2-1 2.1.1 Existing Conditions/Summary of Current Activities, and Changes Since 2008 2-1 2.1.2 Alternatives Development and Screening ...... 2-4 2.1.3 Overview of Alternatives Considered in Detail ...... 2-5 2.1.4 Features Common to All Alternatives ...... 2-5 2.1.5 Best Management Practices (BMPs) ...... 2-7 2.2 Action Alternatives Including Proposed Action ...... 2-9 2.2.1 Alternative 1: Proposed Action ...... 2-9 2.2.2 Alternative 2: No Action Alternative ...... 2-12 2.2.3 Alternative 3: Partial IID Water Supply Alternative ...... 2-13 2.2.4 Alternative 4: Full IID Water Supply Alternative ...... 2-14 2.2.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative...... 2-14

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2.2.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative...... 2-15 2.2.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative...... 2-15 2.2.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative...... 2-15 2.3 Comparison of Adverse Effects by Alternatives ...... 2-16 2.4 Preferred Alternative ...... 2-16 2.4.1 Federal Lead Agency (BLM) Preferred Alternative ...... 2-16 2.4.2 USACE Least Environmentally Damaging Practicable Alternative ...... 2-16

Chapter 3 - Affected Environment and Environmental Effects ...... 3.1-1 3.1 Introduction ...... 3.1-1 3.1.1 Chapter 3 Overview ...... 3.1-1 3.1.2 Resources not Consider...... 3.1-1 3.1.3 Impact Analysis Methodology ...... 3.1-1 3.2 Geology/Mineral Resources/Paleontology ...... 3.2-1 3.2.1 Affected Environment ...... 3.2-1 3.2.2 Methodology ...... 3.2-2 3.2.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals ...... 3.2-3 3.2.4 Direct and Indirect Effects ...... 3.2-3 3.2.4.1 Alternative 1: Proposed Action ...... 3.2-3 3.2.4.2 Alternative 2: No Action Alternative ...... 3.2-4 3.2.4.3 Alternative 3: Partial IID Water Supply Alternative ...... 3.2-5 3.2.4.4 Alternative 4: Full IID Water Supply Alternative ...... 3.2-5 3.2.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative ...... 3.2-6 3.2.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative ...... 3.2-6 3.2.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative ...... 3.2-7 3.2.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative ...... 3.2-7 3.2.5 Cumulative Effects...... 3.2-8 3.2.5.1 Geographic Scope of the Cumulative Effects Analysis ...... 3.3-8 3.2.5.2 Timeframe of the Cumulative Effects Analysis...... 3.3-8 3.2.5.3 Past, Present and Reasonably Foreseeable Actions ...... 3.3-9 3.2.6 Mitigation Measures ...... 3.2-10 3.2.7 Residual Effects after Mitigation ...... 3.2-10 3.3 Hydrology and Water Quality ...... 3.3-1 3.3.1 Affected Environment ...... 3.3-1

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3.3.1.1 Surface Water Hydrology ...... 3.3-1 3.3.1.2 Groundwater Hydrology ...... 3.3-2 3.3.2 Methodology ...... 3.3-3 3.3.2.1 Surface Water Hydrology ...... 3.3-4 3.3.2.2 Groundwater Hydrology ...... 3.3-7 3.3.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals ...... 3.3-9 3.3.4 Direct and Indirect Effects ...... 3.3-10 3.3.4.1 Alternative 1: Proposed Action ...... 3.3-10 3.3.4.2 Alternative 2: No Action Alternative ...... 3.3-12 3.3.4.3 Alternative 3: Partial IID Water Supply Alternative ...... 3.3-12 3.3.4.4 Alternative 4: Full IID Water Supply Alternative ...... 3.3-13 3.3.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative ...... 3.3-13 3.3.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative ...... 3.3-13 3.3.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative ...... 3.3-14 3.3.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative ...... 3.3-14 3.3.5 Cumulative Effects...... 3.3-14 3.3.5.1 Geographic Scope of the Cumulative Effects Analysis ...... 3.3-14 3.3.5.2 Timeframe of the Cumulative Effects Analysis...... 3.3-14 3.3.5.3 Past, Present and Reasonably Foreseeable Actions ...... 3.3-14 3.3.6 Mitigation Measures ...... 3.3-15 3.3.7 Residual Effects After Mitigation ...... 3.3-15 3.4 Vegetation & Wildlife...... 3.4-1 3.4.1 Affected Environment ...... 3.4-1 3.4.2 Methodology ...... 3.4-3 3.4.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals ...... 3.4-4 3.4.4 Direct and Indirect Effects ...... 3.4-4 3.4.4.1 Alternative 1: Proposed Action ...... 3.4-4 3.4.4.2 Alternative 2: No Action Alternative ...... 3.4-8 3.4.4.3 Alternative 3: Partial IID Water Supply Alternative ...... 3.4-8 3.4.4.4 Alternative 4: Full IID Water Supply Alternative ...... 3.4-10 3.4.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative ...... 3.4-10 3.4.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative ...... 3.4-11 3.4.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative ...... 3.4-12

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3.4.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative ...... 3.4-13 3.4.5 Cumulative Effects...... 3.4-14 3.4.5.1 Geographic Scope of the Cumulative Effects Analysis ...... 3.4-14 3.4.5.2 Timeframe of the Cumulative Effects Analysis...... 3.4-14 3.4.5.3 Past, Present and Reasonably Foreseeable Actions ...... 3.4-15 3.4.6 Mitigation Measures ...... 3.4-18 3.4.7 Residual Effects after Mitigation ...... 3.4-23 3.5 Air Quality ...... 3.5-1 3.5.1 Affected Environment ...... 3.5-1 3.5.2 Methodology ...... 3.5-2 3.5.3 Changes in Attainment Designations, Applicable Regulations, Plans, and Policies/Management Goals...... 3.5-5 3.5.4 Direct and Indirect Effects ...... 3.5-7 3.5.4.1 Alternative 1: Proposed Action ...... 3.5-9 3.5.4.2 Alternative 2: No Action Alternative ...... 3.5-11 3.5.4.3 Alternative 3: Partial IID Water Supply Alternative ...... 3.5-11 3.5.4.4 Alternative 4: Full IID Water Supply Alternative ...... 3.5-11 3.5.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative ...... 3.5-12 3.5.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative ...... 3.5-12 3.5.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative ...... 3.5-13 3.5.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative ...... 3.5-13 3.5.5 Cumulative Effects...... 3.5-13 3.5.5.1 Geographic Scope of the Cumulative Effects Analysis ...... 3.5-14 3.5.5.2 Timeframe of the Cumulative Effects Analysis...... 3.5-14 3.5.5.3 Past, Present and Reasonably Foreseeable Actions ...... 3.5-14 3.5.6 Mitigation Measures ...... 3.5-15 3.5.7 Residual Effects after Mitigation ...... 3.5-15 3.6 Cultural Resources...... 3.6-1 3.6.1 Affected Environment ...... 3.6-1 3.6.2 Methodology ...... 3.6-5 3.6.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals ...... 3.6-6 3.6.4 Direct and Indirect Effects ...... 3.6-7 3.6.4.1 Alternative 1: Proposed Action ...... 3.6-7 3.6.4.2 Alternative 2: No Action Alternative ...... 3.6-8 3.6.4.3 Alternative 3: Partial IID Water Supply Alternative ...... 3.6-8 3.6.4.4 Alternative 4: Full IID Water Supply Alternative ...... 3.6-9

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3.6.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative ...... 3.6-9 3.6.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative ...... 3.6-10 3.6.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative ...... 3.6-10 3.6.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative ...... 3.6-10 3.6.5 Cumulative Effects...... 3.6-11 3.6.5.1 Geographic Scope of the Cumulative Effects Analysis ...... 3.6-11 3.6.5.2 Timeframe of the Cumulative Effects Analysis...... 3.6-11 3.6.5.3 Past, Present and Reasonably Foreseeable Actions ...... 3.6-11 3.6.6 Mitigation Measures ...... 3.6-12 3.6.7 Residual Effects after Mitigation ...... 3.6-13 3.7 Special Designations ...... 3.7-1 3.7.1 Affected Environment ...... 3.7-1 3.7.2 Methodology ...... 3.7-2 3.7.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals ...... 3.7-2 3.7.4 Direct and Indirect Effects ...... 3.7-2 3.7.4.1 Alternative 1: Proposed Action ...... 3.7-2 3.7.4.2 Alternative 2: No Action Alternative ...... 3.7-4 3.7.4.3 Alternative 3: Partial IID Water Supply Alternative ...... 3.7-4 3.7.4.4 Alternative 4: Full IID Water Supply Alternative ...... 3.7-4 3.7.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative ...... 3.7-5 3.7.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative ...... 3.7-5 3.7.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative ...... 3.7-5 3.7.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative ...... 3.7-5 3.7.5 Cumulative Effects...... 3.7-6 3.7.5.1 Geographic Scope of the Cumulative Effects Analysis ...... 3.7-6 3.7.5.2 Timeframe of the Cumulative Effects Analysis...... 3.7-6 3.7.5.3 Past, Present and Reasonably Foreseeable Actions ...... 3.7-6 3.7.6 Mitigation Measures ...... 3.7-7 3.7.7 Residual Effects after Mitigation ...... 3.7-7 3.8 Recreation ...... 3.8-1 3.8.1 Affected Environment ...... 3.8-1 3.8.2 Methodology ...... 3.8-2

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3.8.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals ...... 3.8-3 3.8.4 Direct and Indirect Effects ...... 3.8-3 3.8.4.1 Alternative 1: Proposed Action ...... 3.8-3 3.8.4.2 Alternative 2: No Action Alternative ...... 3.8-4 3.8.4.3 Alternative 3: Partial IID Water Supply Alternative ...... 3.8-4 3.8.4.4 Alternative 4: Full IID Water Supply Alternative ...... 3.8-4 3.8.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative ...... 3.8-5 3.8.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative ...... 3.8-5 3.8.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative ...... 3.8-5 3.8.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative ...... 3.8-5 3.8.5 Cumulative Effects...... 3.8-6 3.8.5.1 Geographic Scope of the Cumulative Effects Analysis ...... 3.8-6 3.8.5.2 Timeframe of the Cumulative Effects Analysis...... 3.8-6 3.8.5.3 Past, Present and Reasonably Foreseeable Actions ...... 3.8-6 3.8.6 Mitigation Measures ...... 3.8-6 3.8.7 Residual Effects after Mitigation ...... 3.8-7 3.9 Socioeconomics and Environmental Justice ...... 3.9-1 3.9.1 Affected Environment ...... 3.9-1 3.9.2 Methodology ...... 3.9-1 3.9.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals ...... 3.9-4 3.9.4 Direct and Indirect Effects ...... 3.9-5 3.9.4.1 Alternative 1: Proposed Action ...... 3.9-5 3.9.4.2 Alternative 2: No Action Alternative ...... 3.9-6 3.9.4.3 Alternative 3: Partial IID Water Supply Alternative ...... 3.9-6 3.9.4.4 Alternative 4: Full IID Water Supply Alternative ...... 3.9-7 3.9.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative ...... 3.9-7 3.9.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative ...... 3.9-8 3.9.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative ...... 3.9-8 3.9.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative ...... 3.9-8 3.9.5 Cumulative Effects...... 3.9-9 3.9.5.1 Geographic Scope of the Cumulative Effects Analysis ...... 3.3-9 3.9.5.2 Timeframe of the Cumulative Effects Analysis...... 3.3-9

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3.9.5.3 Past, Present and Reasonably Foreseeable Actions ...... 3.3-9 3.9.6 Mitigation Measures ...... 3.9-9 3.9.7 Residual Effects after Mitigation ...... 3.9-10 3.10 Other Resources Supplemental Analysis...... 3.10-1 3.10.1 Affect Environment ...... 3.10-1 3.10.2 Methodology ...... 3.10-2 3.10.3 Direct and Indirect Effects ...... 3.10-3 3.10.4 Cumulative Effects...... 3.10-4 3.10.4.1 Geographic Scope of the Cumulative Effects Analysis ...... 3.10-4 3.10.4.2 Timeframe of the Cumulative Effects Analysis...... 3.10-5 3.10.4.3 Past, Present and Reasonably Foreseeable Actions ...... 3.10-5 3.10.5 Mitigation Measures ...... 3.10-5 3.10.6 Residual Effects After Mitigation ...... 3.10-5 3.11 Irreversible and Irretrievable Commitment of Resources ...... 3.11-1 3.12 Growth Inducing Impacts ...... 3.12-1

Chapter 4 – Consultation, Coordination, and Public Involvement ...... 4-1 4.1 Interrelationships/Interagency Coordination ...... 4-1 4.1.1 The USACE and the USEPA ...... 4-1 4.1.2 Endangered Species Act: Section 7 Compliance ...... 4-1 4.1.3 National Historic Preservation Act: Section 106 Compliance ...... 4-1 4.2 Tribal Consultation ...... 4-2 4.3 Public Involvement ...... 4-2 4.4 Implementation, Monitoring and Enforcement...... 4-3 4.4.1 Implementation and Monitoring ...... 4-3 4.4.2 Enforcement and Adaptive Management ...... 4-3 4.5 Individuals Consulted and List of Supplemental EIS Preparers ...... 4-4

Chapter 5 – References ...... 5-1

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List of Tables

Table 1-1 List of Federal Requirements for the Proposed Action ...... 1-9

Table 2-1 Existing and Planned Disturbance ...... 2-11 Table 2-2 Comparison of Effects by Alternative ...... 2-17

Table 3.3-1 Existing Condition Unit Hydrograph Peak Flowrate ...... 3.3-10 Table 3.3-2 Proposed Condition Unit Hydrograph Peak Flowrate ...... 3.3-10

Table 3.5-1 Reported Air Quality Pollutant Concentrations as Monitored at Nearest Imperial County Monitoring Stations ...... 3.5-3 Table 3.5-2 Estimated Air Pollutant Emissions Existing Conditions and Proposed Project Operations ...... 3.5-8 Table 3.5-3 Total Emissions – Mobile and Fugitive Proposed Project Operations And Alternatives ...... 3.5-10

Table 3.6-1 Previously Recorded Cultural Resources Relocated within the Project APE ... 3.6-2 Table 3.6-2 Cultural Resources Newly Recorded in 2018 within the Project Area of Potential Effects...... 3.6-5

Table 3.9-1 Employment by Industry Section...... 3.9-2 Table 3.9-2 Minority and Low-Income Populations ...... 3.9-4 Table 3.9-3 Applicable Laws, Ordinances, Regulations, and Standards ...... 3.9-5

Table 3.11-1 Projected Use of Non-Renewable Resources for USG Expansion Project ..... 3.11-2

List of Figures (All figures are included in Appendix B, Figures)

Figure 1-1: Vicinity Map and Regional Location

Figure 2-1: Plant and ROW CACA-044014 Location Figure 2-2: Mine Plan Figure 2-3: Quarry Geologic Summary Figure 2-4: Typical Quarry Cross Section “A” Figure 2-5: Westside Main Canal Pipeline Alternatives Figure 2-6: Modified Lower Watershed Mining Footprint A Figure 2-7: Lower Quarry Watershed Reduced Mining Footprint Alternative B Figure 2-8: Middle Quarry Watershed Phased Elimination Alternative Figure 2-9: Upper Quarry Watershed Reduced Mining Footprint Alternative

Figure 3.5-1 Air Monitoring Stations / Nonattainment Areas

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Appendices

Appendix A Determination of NEPA Adequacy Appendix B Figures Appendix C Glossary of Terms Appendix D Plan of Operations, March 2018 Appendix E Table of 2008 Mitigation Measures and New Mitigation Measures Appendix F Cumulative Projects Appendix G Paleontological Resources Report Appendix H Hydrology Study Appendix I Update on Groundwater Conditions Memorandum Appendix J 2016 Jurisdictional Delineation Appendix K 2010 Jurisdictional Delineation of IID Water Supply Pipeline Appendix L Biological Resources Technical Report Appendix L-1 Tamarisk Removal Plan Appendix M Biological Resources Technical Report for IID Canal Water Pipeline Appendix N Air Quality Emission Tables Appendix O Cultural Resources Report Appendix P DRECP CMA Spreadsheet Appendix Q Scoping Summary Report

U.S. Gypsum Draft SEIS ix July 2019 ACRONYMS AND ABBREVIATIONS

ABDSP Anza-Borrego Desert State Park ACEC Area of Critical Environmental Concern ACHP Advisory Council on Historic Preservation ACS American Community Survey AES Agricultural Experiment Station program AHA Activity Hazard Analysis AIRFA American Indian Religious Freedom Act ANFO Ammonium Nitrate Fuel Oil APE Area of Potential Effect APN Assessor’s Parcel Number Applicant United States Gypsum Company ARMR Archaeological Resource Management Report ARPA Archaeological Resources Protection Act of 1979 amsl above mean sea level ATCC Area of Traditional Cultural Concern ATV all-terrain vehicle BA Biological Assessment BACM Best Available Control Measures BLM United States Bureau of Land Management BMPs Best Management Practices BO burrowing owl CAA Clean Air Act CARB California Air Resources Board CDCA California Desert Conservation Area CDCA Plan California Desert Conservation Area Plan CDFG California Department of Fish and Game CDFW California Department of Fish and Wildlife CERCLA Comprehensive Environmental Response and Liability Act CEQ Council on Environmental Quality CEQA California Environmental Quality Act CESA California Endangered Species Act CFR Code of Federal Regulations CHRIS California Historical Resources Information System CMAs Conservation and Management Actions CNDDB California Natural Diversity Database CNPS California Native Plant Society CONs Ecological and Cultural Conservation CRPR California Rare Plant Rank CRR Cultural Resources Report CSC California Species of Special Concern CUP Conditional Use Permit CWA Clean Water Act DFA Development Focus Areas DNA Determination of NEPA Adequacy DOI United States Department of Interior DOT United States Department of Transportation

July 2019 x U.S. Gypsum Draft SEIS ACRONYMS AND ABBREVIATIONS

DRECP California Desert Renewable Energy Conservation Plan EIR Environmental Impact Report EIS Environmental Impact Statement EO Executive Order EPA United Stated Environmental Protection Agency ESA Endangered Species Act FEIR Final Environmental Impact Report FEIS Final Environmental Impact Statement FESA Federal Endangered Species Act FLMPA Federal Land Management and Policy Act FR Federal Register FS United States Forest Service FTHL flat-tailed horned lizard Gpd gallons per day GPL General Public Lands HA hydrologic area HAZWOPER Hazardous Waste Operations and Emergency Response HDPE high-density polyethylene HEC-RAS Hydrologic Engineering Center-River Analysis System HRMP Historic Resources Management Plan HSWA Hazardous and Solid Waste Act HU hydrologic unit I-8 Interstate-8 ICAPCD Imperial County Air Pollution Control District ICGMC Imperial County Groundwater Management Committee IID Imperial Irrigation District IMSA Inert Material Storage Area JD Jurisdictional Delineation LEDPA Least Environmentally Damaging Practicable Alternative LUPA Land Use Plan Amendment MBTA Migratory Bird Treaty Act MLD Most Likely Descendant MM Mitigation Measure MOA Memorandum of Agreement MOU Memorandum of Understanding MSHA Mine Safety and Health Administration MW megawatt NAAQS National Ambient Air Quality Standards NAHC Native American Heritage Commission NCL National Conservation Lands NEPA National Environmental Policy Act NHPA National Historic Preservation Act NOAA National Oceanic and Atmospheric Administration NOI Notice of Intent NPS National Park Service NRCS Natural Resource Conservation Service

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NRHP National Register of Historic Places OHWM Ordinary High Water Mark OHV off-highway vehicle OSHA Occupational Safety and Health Administration PBS Peninsular bighorn sheep PoO Plan of Operations PM10 particulate matter less than 10 microns in diameter PM2.5 particulate matter less than 2.5 microns in diameter ppm parts per million PRC Public Resources Code PRMMP Paleontological Resources Monitoring and Mitigation Plan PRPA Paleontological Resources Preservation Act PV photovoltaic PYFC Potential Fossil Yield Classification RCRA Resource Conservation and Recovery Act REP Renewable Energy Projects ROD Record of Decision ROW right-of-way RWQCB Regional Water Quality Control Board SARA Superfund Amendments and Reauthorization Act SHPO State Historic Preservation Office SIP State Implement Plan SMARA Surface Mining and Reclamation Act SRMA Special Recreation Management Area TNW traditional navigable water USACE United States Army Corps of Engineer USEPA United States Environmental Protection Agency USFWS United States Fish and Wildlife Service USG United State Gypsum Company USGS United States Geological Survey VRM Visual Resource Management WA Wilderness Areas WEAP worker education awareness program WECO Western Colorado

July 2019 xii U.S. Gypsum Draft SEIS Chapter 1: Introduction

CHAPTER 1: INTRODUCTION

1.1 SUPPLEMENTAL EIS PURPOSE AND USE

This Draft Supplemental Environmental Impact Statement (Draft Supplemental EIS) updates the 2006 Draft and 2008 Final Environmental Impact Report/Environmental Impact Statement (EIR/EIS) for the United States Gypsum Company (USG) Expansion/Modernization Project. The 2006 Draft and 2008 Final EIR/EIS evaluated the proposed expansion and modernization of USG’s manufacturing facilities at its Plaster City Plant (Plant) and gypsum quarrying operations at its Plaster City Quarry (Quarry). This supplement considers the Proposed Action and seven alternatives, including a No Action alternative; it includes new alternatives, new information related to threatened and endangered species, and new circumstances or new information related to the federal aspects of the Proposed Action.

1.1.1 Background

USG owns and operates a gypsum quarry and processing plant in Imperial County, California (Figure 1-1). USG’s Quarry holdings total approximately 2105 acres, of which 2,032 acres are owned by USG and 73 acres are active unpatented mineral claims.

As presented in Section 3.3.3.7 of the 2006 Draft EIR/EIS, the hydrological analysis concluded that under baseline conditions (i.e., no increase in water usage by U.S. Gypsum above the average 347 AF per year), water levels in the Basin would decline by up to 10 feet over the next

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80 years. With the project, the estimated drawdown within the alluvial aquifer after 80 years of pumping would be approximately 30 feet. Section 3.3.7 of the Draft EIR/EIS also states that this drawdown could potentially lower the water level in some wells, and that if the water level in a particular well were to drop to near the base of the screened interval, the ability to maintain current pumping rates at that well could potentially be reduced. Two Mitigation Measures were presented to reduce the level of significance of identified impacts on groundwater levels and groundwater quality. After the County released the 2008 Final EIR/EIS the Imperial County Board of Supervisors certified the EIR/EIS, adopting findings of fact, a statement of overriding consideration, and a mitigation monitoring program in compliance with CEQA. The County Board of Supervisors filed a Notice of Determination on March 19, 2008.

The Sierra Club subsequently argued in Court that the Final EIR/EIS did not adequately describe feasible measures which could minimize and reduce the Project’s significant adverse impacts on individual wells. On December 16, 2013, the Court of Appeal reversed a prior Superior Court order, holding that there was insufficient evidence to support the County’s conclusion that the Mitigation Measures for the Project, as adopted in January 2008, would be viable or effective in reducing the Project’s potential impacts on individual groundwater wells to a level of insignificance. As a result, in October 2018, the Sierra Club, Imperial County and the Imperial County Planning Commission, and USG (referred to collectively as the “Parties”) entered into settlement negotiations. Under the Settlement Agreement, the Parties agree that USG will make a good faith effort to supply part of its processing water from an alternative source (the “Partial Use of Water from Imperial Irrigation District” described in the 2006 draft EIR/EIS). Because the Settlement Agreement is still pending final approval and implementation, it is not addressed in this Draft Supplemental EIS as a component of the Proposed Action, but instead as Alternative 3: Partial IID (Imperial Irrigation District) Water Supply.

Subsequent to certification of the 2008 Final EIR/EIS, USG proceeded to conduct quarrying operations within its private land at the Quarry under the conditions and approvals provided by Imperial County and the State of California consistent with stipulations outlined by the County. Continued development of the Quarry, consistent with the most current State-approved Mine Reclamation Plan (June 2003), includes alluvial quarrying in certain areas of the Quarry that are subject to a CWA Section 404 Permit from the USACE. In March 2014, USG submitted a request for a CWA Section 404 Permit to the USACE for expansion of operations into alluvial portions of the Quarry. The USACE determined in its initial evaluation of the application that an EIS-level analysis would be required to evaluate impacts to waters of the United States, including a CWA Section 404(b)(1) alternative analysis (pursuant to 40 Code of Federal Regulations [CFR] Part 230).

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(c)(1)) and (c)(4)) state that agencies shall prepare supplements to either draft or final environmental impact statements if: i) the agency makes substantial changes in the proposed action that are relevant to environmental concerns; or ii) there are significant new circumstances or information relevant to environmental concerns and bearing on the proposed action or its impacts. 40 CFR Section 1502.9 (c)(4)) states that agencies shall prepare, circulate, and file a supplement to a statement in the same fashion (exclusive of scoping) as a draft and final statement unless alternative procedures are approved by the Council on Environmental Quality. The USACE intends to adopt this Supplemental EIS to support its decision regarding USG’s CWA Section 404 Permit application.

Pursuant to 43 CFR 3809.1-5 USG submitted a Revised Plan of Operation for the gypsum quarrying operations describing the proposed operation and reclamation reflecting unpatented placer mining claims on public lands totaling 73.2 acres. USG submitted the 2018 Revised Plan of Operations specific to the BLM-managed public lands. USG also has an approved Plan of Operations as submitted to the Imperial County Planning Department for quarrying and reclamation on private properties.

In July 2018, BLM accepted the draft Plan of Operations as complete. A record of decision on the Plan is part of the Proposed Action currently subject to this NEPA review. Elements of the 2018 Plan of Operations reviewed by BLM are summarized in Section 2.1.1 of this Supplemental EIS. The complete Plan of Operations is included as an appendix.

1.1.2 Supplemental EIS Scope

To date, the components of the Proposed Action on public lands have not been implemented. The scope of this Supplemental EIS is limited to aspects of the Proposed Action as described in the 2008 Final EIR/EIS that have not been implemented and that are subject to federal authorizations. This supplement includes consideration of alternatives to the proposed mine expansion; the 2006 Draft and 2008 Final EIR/EIS did not consider any because USG had not yet filed an application for a permit under Section 404 (b)(1) (40 CFR Part 230).

The Proposed Action includes operating and expanding the Quarry in accordance with its current Mine Reclamation Plan and Plan of Operations, replacing the existing Plant water supply pipeline, and constructing a new water supply pipeline with electrical service to a proposed well that would supply the Quarry with water. Each of these pipeline installations would require a right-of-way grant from the BLM for those portions of the lines on public lands.

This Draft Supplemental EIS:

 Adds new alternatives consistent with the requirements of CWA 404(b)(1) guidelines;  Adds and evaluates new information related to threatened and endangered species, including but not limited to Peninsular bighorn sheep (PBS) (Ovis canadensis nelsoni) Distinct Population Segment;  Re-evaluates the affected environment as included in the 2006 Draft and 2008 Final EIR/EIS, and

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 Describes the new circumstances or new information that triggered the need for supplementation as related to the federal aspects of the Proposed Action not implemented to date.

1.1.3 BLM Purpose and Need

Decisions to be made:

1.1.4 USACE Draft Section 404(b)(1) Alternatives Analysis Basic and Overall Project Purpose and Need

The project purpose frames the scope of the Section 404(b)(1) alternatives analysis. For Section 404(b)(1) evaluations, project purpose is expressed in terms of “basic purpose” and “overall purpose.” While these terms are not strictly defined in the guidelines, in practical application, they are generally defined as presented below.

Basic Project Purpose – The basic project purpose comprises the fundamental, essential, or irreducible purpose of the proposed project, and is used by the USACE to determine whether the applicant’s project is water-dependent. The Section 404(b)(1) Guidelines state that if an activity associated with the discharge proposed for a water body does not require access or proximity to, or siting within, water to fulfill its basic purpose, the activity is not water-dependent. The Project’s basic project purpose is mineral resource mining, and therefore, it is not water- dependent.

Overall Project Purpose – The overall project purpose serves as the basis for the Section 404(b)(1) alternatives analysis and is determined by further defining the basic project purpose in a manner that more specifically describes the applicant’s goals for the project, and which allows a reasonable range of alternatives to be analyzed. It should not be so narrowly defined as to give undue deference to the applicant’s wishes, thereby unreasonably limiting the consideration of alternatives. Conversely, it should not be so broadly defined as to render the evaluation unreasonable and meaningless. The USACE, USG, and USEPA coordinated in the development

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of an overall project purpose that met the needs of USG, while adhering to the guidance by the USEPA. The overall project purpose as agreed to by all parties on June 13, 2018, is:

“To maintain a reliable supply of gypsum ore to existing processing facilities in order to produce gypsum-related agricultural products and residential and commercial building products including, but not limited to, wallboard, cement, industrial and building plasters, stucco, soil amendments and conditioners, and gypsum by-products, at levels consistent with current and projected demand in the southwestern United States.”

1.1.5 Applicant’s Objectives

The purpose of the Proposed Action is to provide USG with authorization for the expansion of its existing Quarry onto public lands that have active, unpatented mill site claims held by USG and consistent with the Quarry’s State approved Mine Reclamation Plan (June 2003). USG’s current objectives, which have evolved since the 2008 Final EIR/EIS and the Supplemental EIS Scoping Meeting, include:

 Secure permits and approvals to continue and fully develop quarrying gypsum reserves;  Maximize the recovery of known gypsum reserves needed for the Plant to fulfill its estimated operational design life;  Meet market demands for gypsum products;  Develop and maintain a replacement Quarry water supply designed to meet dust suppression requirements;  Sustain an adequate water supply for manufacturing operations by replacing an existing deteriorating water pipeline with a new pipeline; and  Concurrently reclaim Quarry site for post-mining uses as Open Space.

1.2 GENERAL LOCATION AND MAP

Quarry mining first began at the Plaster City Quarry location in the 1920s and USG began operating the Quarry in 1945. Figure 1-1 shows the Vicinity Map and Regional Location of the Plaster City Quarry, Plaster City Plant, and existing/proposed water pipelines (see Appendix B for figures). Gypsum rock is mined at the Quarry for processing at the Plant located to the south of the Quarry, into gypsum-related agricultural products and residential and commercial building products to meet market demand in the southwestern United States.

Both the Quarry and the Plant use existing water supplies to provide for dust abatement at the Quarry and manufacturing needs at the Plant. The Quarry water is obtained from a well on USG- owned land north of the Quarry. Additional water needed for dust suppression at the Quarry is supplied by railroad tank car delivery from the Plant. Water for Plant operations is obtained from USG-owned wells located near the community of Ocotillo.

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1.3 MAJOR AUTHORIZING LAWS AND REGULATIONS

The primary agency-specific authorizing laws and regulations are summarized below.

1.3.1 Bureau of Land Management

The BLM’s authority and policy guidance for making decisions related to the Proposed Action is pursuant to 43 CFR Part 3809, and under the FLPMA Sections 302(b), 601(a)(4), and 601(b). Title V of FLPMA provides for the issuance of permits and right-of-way authorizations. The General Mining Law of 1872 authorizes and governs prospecting and mining on federal public lands. The FLPMA did not amend the 1872 Mining Law, which allows for mineral development or mineral production within the CDCA.

1.3.2 U.S. Army Corps of Engineers

The USACE has authority to issue permits under the Federal CWA. Section 404 of the CWA authorizes the Secretary of the Army, acting through the USACE, to issue permits regulating the discharge of fill material into waters of the United States. Throughout this Supplemental EIS process, the BLM has provided information to the USACE to assist them in making determinations regarding their jurisdiction and need for a Section 404 permit. An applicant for a Section 404 permit must demonstrate to the USACE that, among other things, the proposed project is the least environmentally damaging practicable alternative (LEDPA) to achieve the project’s purpose (40 CFR section 230.10(a)). The 404(b)(1) Guidelines are the substantive criteria the USACE uses to determine a project’s environmental impacts on aquatic resources from discharges of dredged or fill material.

1.4 RELATIONSHIP TO STATUTES, POLICIES, AND PLANS

1.4.1 Federal Statutes, Policies, and Plans

Antiquities Act of 1906: (16 USC 431-433) This act authorizes the President of the United States to declare historic landmarks, historic and prehistoric structures, and other objects of historic or scientific interest on lands owned or controlled by the federal government to be national monuments. Although neither the Act nor its uniform rules and regulations (Title 43 Part 3, 43 CFR 3) specifically mention natural or paleontological resources, the term "objects of antiquity" has been interpreted to include fossils by the National Park Service (NPS), the BLM, the Forest Service (FS), and other federal agencies.

Clean Air Act: The Federal Clean Air Act (CAA) of 1970, 42 United States Code (USC) 7401 et seq., as amended, regulates air emissions from stationary and mobile sources, including authorizing the USEPA to establish National Ambient Air Quality Standards (NAAQS) to protect public health and public welfare and to regulate emissions of hazardous air pollutants.

Clean Water Act: The Clean Water Act (CWA; 33 USC 1251-1376) provides guidance for the restoration and maintenance of the chemical, physical, and biological integrity of the nation’s waters. Section 404 establishes a permit program administered by the USACE regulating the

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discharge of dredged or fill material into waters of the United States, including wetlands. The CWA also contains the requirements under which the Regional Water Quality Control Board (RWQCB) set water quality standards for all contaminants in surface waters.

Endangered Species Act of 1973: Management activities on private and public lands are subject to the Federal Endangered Species Act of 1973 (ESA), as amended. The ESA directs project proponents or government agencies, as appropriate, to consult with the U.S. Fish and Wildlife Service (USFWS) and/or National Oceanic and Atmospheric Administration Fisheries Service (NOAA Fisheries) to address the effects of management activities on threatened and endangered species and designated critical habitats. Consultation leads to the issuance of a Biological Opinion and may result in issuance of a Section 10(a) permit (for non-Federal actions) or a Section 7 permit (for Federal actions) by the USFWS and/or NOAA Fisheries.

Federal Land Policy and Management Act (FLPMA) of 1976: The Federal Land Management and Policy Act (FLMPA) of 1976 (43 USC 1701) provides the BLM’s overarching mandate to manage the lands and resources under its stewardship based on the principles of multiple use and sustained yield. Title VI of FLPMA requires that the Secretary of the Interior provide for the immediate and future protection and administration of the public lands in the California desert within the framework of a program of multiple use, sustained yield, and the maintenance of environmental quality. It also includes objectives such as the evaluation, management, protection, and location of fossils on BLM-managed lands, defines fossils, and lays out penalties for the destruction of significant fossils.

General Mining Act of 1872, as Amended (also known as the Mining Law of 1872): (30 U.S.C 28 et seq.) - This law, approved on May 10, 1872, opened the public lands of the United States to mineral acquisition by the location and maintenance of mining claims and codified the informal system of acquiring and protecting mining claims on public land. Mineral deposits subject to location are generally referred to as "locatable minerals." Locatable minerals include both metallic minerals (gold, silver, lead, copper, zinc, nickel, etc.) and nonmetallic minerals (fluorspar, mica, certain limestones and gypsum, tantalum, heavy minerals in placer form, and gemstones).

National Environmental Policy Act: The National Environmental Policy Act (NEPA), signed into law in 1970, requires Federal agencies to assess the environmental effects of their proposed actions prior to making decisions. This legislation directs Federal agencies to maintain conditions under which people and nature can exist in productive harmony and fulfill the social, economic, and other requirements of present and future generations of Americans. The law requires that all Federal actions that could result in a significant impact on the environment to be subject to review by Federal, tribal, State, and local environmental authorities, as well as affected parties and interested citizens.

National Historic Preservation Act of 1966, as Amended: The National Historic Preservation Act (NHPA) is the primary Federal law providing for the protection and preservation of cultural resources. The NHPA established the National Register of Historic Places, the Advisory Council on Historic Preservation, and the State Office of Historic Preservation. It requires that Federal agencies provide the State Historic Preservation Office (SHPO), any potentially affected Indian

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tribe, and the Advisory Council on Historic Preservation (ACHP) with an opportunity to comment on Federal actions that may impact cultural resources.

Paleontological Resources Preservation Act (PRPA): Title VI, Subtitle D in the Omnibus Public Lands Act of 2009 was signed into law on March 30, 2009 (Public Law 111-11, Title VI, Subtitle D; 16 U.S.C. §§ 470aaa - 470aaa-11). PRPA directs the Department of Agriculture (U.S. Forest Service) and the Department of the Interior (National Park Service, Bureau of Land Management, Bureau of Reclamation, and Fish and Wildlife Service) to implement comprehensive paleontological resource management programs.

California Desert Conservation Area Plan, as amended: In accordance with Title 6 of FLPMA the BLM issued the California Desert Conservation Area (CDCA) Plan in 1980, which has been amended over 100 times since its adoption. The CDCA encompasses 25 million acres in southern California designated by Congress in 1976 through FLPMA, of which the BLM manages about 10 million acres. The CDCA Plan as amended provides overall regional guidance for BLM-administered lands in the CDCA and establishes long-term goals for protection and use of the California desert. The most recent large scale amendment to the CDCA Plan was the Desert Renewable Energy Conservation Plan (DRECP), signed September 14, 2016. The DRECP established new land allocations and Conservation Management Actions (CMAs) that set forth management actions in specific land allocations.

Other Applicable Federal Programs and Laws: Other federal government programs and laws applicable to current and future operation and maintenance of USG’s Quarry, Plant, and water pipelines include, but are not limited to the following:

 Comprehensive Environmental Response and Liability Act (CERCLA). Superfund Amendments and Reauthorization Act (SARA) of 1986 (42 USC Section 9601 et seq.)  Mine Safety and Health Administration (MSHA), 30 CFR, Subchapters A - Q  Occupational Safety and Health Administration (OSHA), 29 CFR 1910  Toxic Substances Control Act (15 USC 2605)/Resource Conservation and Recovery Act (RCRA) (42 USC 6901 et seq.)/Hazardous and Solid Waste Act (HSWA)  U.S. Department of Transportation (DOT). Hazardous Materials Transport Act (49 USC 5101)

1.4.2 State and Local Laws, Plans, Policies, and Programs

California Endangered Species Act: The California Endangered Species Act (CESA) (Fish and Game Code 2050 et seq.) establishes the policy of the State to conserve, protect, restore, and enhance threatened or endangered species and their habitats. CESA mandates that State agencies should not approve projects that would jeopardize the continued existence of threatened or endangered species if reasonable and prudent alternatives are available that would avoid jeopardy. There are no State agency consultation procedures under CESA. For projects that affect a species that is both State and federally listed, compliance with the Federal ESA will satisfy CESA if the California Department of Fish and Wildlife (CDFW) determines that the

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federal incidental take authorization is “consistent” with CESA under Fish and Game Code Section 2080.1 and issues a Consistency Determination to that effect. For projects that will result in a take of a State-only listed species, an applicant must apply for a take permit under Section 2081(b).

California Fish and Game Code, Streambed Alteration Agreements: Sections 1601 to 1603 of the California Fish and Game Code require notifying the California Department of Fish and Wildlife (CDFW) prior to constructing any project that would divert, obstruct, or change the natural flow, bed, channel, or bank of any river, stream, or lake. Preliminary notification and project review generally occur during the environmental review process. When an existing fish or wildlife resource may be substantially adversely affected, the CDFW is required to propose reasonable project changes and/or mitigation to protect the resource. These modifications are formalized in a Streambed Alteration Agreement that becomes part of the plans, specifications, and bid documents for the project.

State Historic Preservation Office (SHPO): The California SHPO reviews State programs and projects that may impact historic resources that are located on state-owned land pursuant to California Public Resources Code §5024 and §5024.5.

1.4.3 List of Required Permits and Approvals

Table 1-1 provides a list of the anticipated federal permits and approvals that would be required.

Table 1-1 List of Federal Requirements for the Proposed Action BLM Plan of Operations on public land Right-of-way grant (Case file number CACA-056908) Right-of-way grant (Case file number CACA-044014) USFWS Biological Opinion USACE CWA Section 404 Department of the Army Permit

1.5 DOCUMENT ORGANIZATION

This document follows regulations promulgated by the CEQ for Implementing the Procedural Provisions of NEPA (40 CFR 1500-1508); the Department of the Interior’s NEPA regulations, 43 CFR Part 46; the BLM NEPA Handbook, H-1790-1; Sections 201, 202, and 206 of FLPMA (43 CFR 1600); and the BLM Land Use Planning Handbook, H1601-1. This Supplemental EIS describes the components of and alternatives to the Proposed Action and environmental consequences of the Proposed Action and alternatives. The Draft Supplemental EIS is organized as follows:

Chapter 1 - Introduction provides general background on the Proposed Action; identifies the purpose and need for the Proposed Action; and identifies roles of the BLM, other agencies, and authorities regulating various aspects of the Proposed Action.

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Chapter 2 - Alternatives describes the Proposed Action, the development and screening of alternatives analyzed in the document, and any alternatives that were considered but not analyzed in detail.

Chapter 3 – Affected Environment and Environmental Effects describes existing conditions in the affected environment that have changed since the 2006 Draft and 2008 Final EIR/EIS, provides a comprehensive analysis and assessment of environmental effects and mitigation measures, and other aspects of the BLM’s compliance with NEPA procedures, including a description of unavoidable adverse impacts and the commitments of resources (40 CFR, 1502.16).

Chapter 4 – Consultation, Coordination, and Public Involvement identifies the persons, groups, agencies, and other governmental bodies that were consulted or that contributed to the preparation of the EIS; the consultation process for ESA Section 7, NHPA Section 106, and Native American tribes; public participation during scoping; a list of EIS preparers; and the implantation, monitoring, and enforcement process.

Chapter 5 - References is a list of References used in preparation of this document.

Appendices include information that supplements or supports the analyses in the body of the EIS/EIR, all figures, and the Glossary of Terms (Appendix C).

1.6 ISSUES TO BE ADDRESSED

The issues evaluated in this Supplemental EIS include the physical, biological, cultural, socioeconomic, and other resources that have the potential to be affected by activities of the Proposed Action and alternatives on federal lands or areas with federal agency jurisdiction. The topics are presented in the order of the 2006 Draft and 2008 Final EIR/EIS which this document supplements.

 Geology/Mineral Resources/Paleontology  Hydrology & Water Quality  Vegetation & Wildlife  Air Quality  Cultural Resources  Special Designations (Land Use)  Recreation  Socioeconomics and Environmental Justice  Other Resource Areas

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CHAPTER 2: PROPOSED ACTION AND ALTERNATIVES

2.1 INTRODUCTION

This chapter describes changes to the Proposed Action and its alternatives and new alternatives developed since the 2006 Draft EIR/EIS and 2008 Final EIR/EIS were issued.

The 2006 Draft and 2008 Final EIR/EIS documents described and analyzed aspects of the Proposed Action at the USG Quarry and the USG Plant separately. This Draft Supplemental EIS provides analyses of environmental issues that are also separately related to either the Quarry or the Plant. The Draft Supplemental EIS focuses the discussion and analyses only on those aspects of the Proposed Action involving federal action that were either absent from the 2008 Final EIR/EIS or have changed since its publication.

2.1.1 Existing Conditions/Summary of Current Activities, and Changes Since 2008

Plaster City Plant: The Plant consists of 473 acres of private land, of which approximately 340 acres are developed and/or disturbed by Plant operation activities. Since 2008, all proposed improvements as described in the United States Gypsum Company Expansion/Modernization Project EIR/EIS, with the exception of improvements to the water system, have been completed. For a detailed description of all aspects of the 2006 Proposed Action refer to Sections 2.3.1 and 2.4.1 of the 2006 Draft EIR/EIS.

Plant operations remain the same as described in the 2006 Draft EIR/EIS, Chapter 2. Operations consist of processing gypsum rock into four basic products: wallboard, industrial and building plasters, stucco, and raw gypsum products. Finished products are stored on-site and subsequently loaded onto rail cars or trucks for transport to market. Since 2008, there has been no increase in employment, production, or water and utility use at the Plant. The Plant location is shown on Figures 1-1 and 2-1.

Plant Water Supply: The Plant’s water supply is drawn from the Ocotillo-Coyote Wells Groundwater Basin through three groundwater wells owned by USG. The wells are located approximately 8 miles west of the Plant near the community of Ocotillo (Figure 2-1). The groundwater is transported to the Plant via an 8-inch gravity-fed water pipeline routed over public lands. The pipeline was installed in the 1920s and is made of Transite, an asbestos- concrete pipe material. The pipeline has exceeded its useful life. The 2006 Proposed Action identified the need to replace the pipeline to improve reliability of the water supply. Replacement of the water pipeline would not increase the amount of groundwater use currently permitted. The water line predates the establishment of the BLM, and no record exists of a right-of-way for it over public lands. Replacement of the line would require that USG obtain a right-of-way grant over public lands from the BLM.

Plaster City Quarry: The Quarry is located in the central-western portion of Imperial County, California (Figure 1-1). USG’s Quarry holdings total approximately 2,105 acres; 2,032 acres are owned by USG and 73 acres are active unpatented mill site claims on BLM-administered public lands.

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As described in the 2006 Draft EIR/EIS, USG previously operated the Quarry under two separate reclamation plans, one for the Plaster City Quarry and one for the Shoveler Annex (shown on Figure 2-2 as S1, S2, and S3). The Proposed Action as described in the 2006 Draft EIR/EIS would combine the two reclamation plans into a single plan. The proposed Mine Reclamation Plan (June 2003) combined the two valid quarry reclamation plans for the USG Plaster City Quarry and the Shoveler Annex into a comprehensive plan that includes all of USG’s mineral holdings. At the time, approximately 408 acres of unpatented placer mine claims and mill site claims located on BLM-administered public lands were incorporated into the Quarry Mine Plan. Since 2006, changes in land ownership have significantly reduced the amount of public land at the Quarry.

Changes in Land Ownership: The Quarry Mine Plan1 as proposed in the Mine Reclamation Plan2 (March 2003) and Plan of Operations3 (September 2004) consisted of a total 2,048-acres including approximately 408 acres of public land. Land ownership and conditions are described below.

BLM Public Lands On December 13, 2007, USG received Patent No. 04-2008-0010. The patent conveyed to USG approximately 304.57 acres of placer mining claims previously identified as public lands in the 2006 and 2008 EIR/EIS documents. The placer mining claims listed below have been incorporated into USG’s private land holdings; development of mining activities on these lands is no longer subject to BLM approval pursuant to 43 C.F.R. § 3809. However, BLM must review the Plan of Operations to ensure that activities in that plan would not cause unnecessary and undue degradation per 43 C.F.R. § 3809 on adjacent, BLM-administered public lands.

1 A Mine Plan is required for an application of land use on private land with a local lead agency under conditions of a CUP or Surface Mine Permit. A Surface Mine Permit is usually a CUP and subject to review under CEQA. The Mine Plan identifies the method and extent of mining to be approved in the permit. A mine plan document is designed to conform to the permit requirements stipulated in the lead agency’s land use permitting procedure and requires review and approval by the local lead agency responsible for implementing the California Surface Mining and Reclamation Act (SMARA). A Mine Plan is essentially the same as a Plan of Operations but does not address all the federal regulations stipulated in 43 C.F.R. § 3809. 2 A Mine Reclamation Plan is required under SMARA. California requires local lead agencies to require all mine plan approvals include a plan for reclamation. The requirements are stipulated in SMARA and are applied by the local lead agency as the representative of the Act (alternatively, the State can review and approve the plan on behalf of the lead agency). All mines approved since 1976 must include a Mine Reclamation Plan an element of which is a Revegetation Plan, and are subject to review under CEQA. The Reclamation Plan is circulated to the State for review with incorporation of the State Division of Mine Reclamation’s recommendations. The Reclamation Plan is a separate permit document that can be revised and amended without changing the Mine Plan. 3 A Plan of Operations is the BLM-required mine plan document required to comply with 43 C.F.R. §3809. It is essentially the Mine Plan formatted to comply with the federal regulations for consideration by BLM on the federal lands subject to their jurisdiction. A Plan of Operations may include the entire mine or portions of a proposed mine and is subject to review under the National Environmental Policy Act (NEPA).

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USG Patented Placer Mining Claims:

 COYOTE (portion of);  “Z;”  YESO (portion of);  Alaska;  BORREGO (portion of);  ARIZONA;  IRONWOOD;  ARKANSAS (portion of);  GYPSY;  CONNECTICUT (portion of);  MESQUITE;  DELAWARE;  “W;”  Indiana;  “X;”  NEW ORLEANS; and,  “Y;”  Montana.

In February 2008, USG formally requested to withdraw from the patent application the remaining portions of claims not included in the mineral patent granted on December 13, 2007. The request for withdrawal included 67.76 acres in the ARKANSAS, CONNECTICUT, COYOTE, YESO, BORREGO, and PROVIDENCE claims deemed non-mineral in character by the BLM Mineral Examiner. The BLM accepted the withdrawal request and issued the patent on December 13, 2007.

Private Land Since 2006, USG has acquired a 40-acre parcel of private land formerly known as the Georgia Pacific property (refer to Figure 2-2). The Georgia Pacific property was previously a privately- owned inholding within the Quarry footprint and was not included in USG’s prior Quarry approvals due to lack of title. USG’s Proposed Action does not include mining or disturbance of this parcel of land; however, the parcel is being included in this Draft Supplemental EIS for purposes of NEPA analysis, CWA Section 404, and U.S. Fish and Wildlife Service (USFWS) Section 7 compliance.

In accordance with 43 C.F.R. § 3809, an updated Plan of Operations describing the quarrying activities was prepared and submitted to the BLM in 2018 for consideration of the Proposed Action at the Quarry. The Plan of Operations is included as Appendix D.

The approved Mine Reclamation Plan consists of a multi-phased plan that would systematically quarry and process up to the current Air Quality Permit-authorized processing rate of approximately 1.92 million tons of gypsum annually. The Mine Reclamation Plan is divided into areas based upon the current geological data, quantity and quality of gypsum, market demand and proximity to the Plant.

Quarry Water Supply: For dust suppression at the Quarry, a water well was drilled in 1983 and permitted under Imperial County Conditional Use Permit (Imperial County CUP) No. 365-83 on the eastern side of the wash. The water was non-potable (due to high dissolved solids) and was used exclusively for dust suppression. Production from the well declined and a replacement well (Well No. 2) was drilled in 1993. Imperial County CUP No. 635-83 was re-issued to the new well site with an approved withdrawal rate of 7,000 gallons per day (gpd). Production from Well No. 2 has also declined and no longer meets operational demands. Under existing conditions,

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water demand for operations at the Quarry is approximately 15,000 gpd; Well No. 2 currently produces 4,500 gpd. Additional water for dust suppression is supplied by railroad tank car from the Plant. USG proposes to develop a new well (Well No. 3) on USG-owned land north of the Quarry. To transport water from Well No. 3, USG proposes to install a water pipeline and electrical supply line across public lands, requiring a right-of-way authorization from the BLM (In this document, where reference is made to this pipeline, the electrical line is understood to be included even if not specifically mentioned.) USG submitted an application for this water line to the BLM (case file number CACA 056908). Its authorization is one of the BLM’s decisions to be supported by this Supplemental EIS. Well No. 3 has not been drilled and remains a connected action.

2.1.2 Alternatives Development and Screening

This section outlines the process used by the BLM to develop the alternatives to be analyzed in this Draft Supplemental EIS. Alternatives considered by the Applicant and the BLM along with those suggested by the public during the scoping process were evaluated using the following NEPA criteria and requirements:

 Was the alternative evaluated in the 2006 Draft and 2008 Final EIR/EIS?  Does the alternative fulfill all or most of the purpose and need, and Applicant objectives identified in Chapter 1 of the Draft Supplemental EIS?  Does the alternative fulfill the USACE Draft Section 404(b)(1) Alternatives Analysis Basic and Overall Project Purpose and Need?  Does the alternative avoid or reduce effects to human/environmental resources associated with the Proposed Action, or, conversely, would the alternative create adverse effects potentially greater than those of the Proposed Action?  Is the alternative feasible to construct, operate, maintain, and decommission? Are there any conflicts between the alternative and the objectives of federal land use plans, policies, or regulations for the area concerned?

Alternatives that met most or all of the criteria listed above were carried forward for analysis and are detailed in Section 2.2. Those that did not meet the above criteria or were eliminated from further analysis in the 2006 Draft EIR/EIS (Section 2.6.5) are listed below, along with the reasons for elimination.

 Drilling of New Production Wells in the Vicinity of the Plant o rejected based on poor water quality and resulting economic and technical factors  Drilling of New Production Wells Within the Ocotillo/Coyote Wells Groundwater Basin o rejected based on hydrologic conditions, groundwater quality, and need to establish new pipeline alignments  Alternative Locations o rejected based on historic establishment of plant and quarry and location of alternative gypsum reserves

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 Inert Material Storage Area o rejected based on economic, environmental, and technological factors  Off-Site Gypsum Sources in California, Nevada, Arizona, Utah, or Mexico o rejected based on the Plaster City Quarry’s ore representing a unique and significant source of gypsum in the region and on the West Coast o off-site locations were considered to be impractical because of: . compromised gypsum quality . small deposit size . long distance from USG’s existing Plaster City production plant . most off-site deposits being owned by USG’s market competitors  Alternative Mining Methods Including Block and Pillar, Block Caving, Long Wall, and Stoping o rejected based on safety and feasibility concerns posed by highly fractured and soft rock quality

Quarry Watershed Modified Mining Footprint Eliminating mining Phases 9, 8, 7 and 6 was considered but was determined to be infeasible for the following reasons: 1) Phases 8 and 9 are at the southernmost terminus of the upper Quarry watershed where the channels are deeply incised by natural erosion and a substantive reduction in losses of waters of the United States is not anticipated and 2) the potential elimination of either Phase 6 or 7 was considered but, similar to issues in the middle Quarry watershed, the elimination of either of these phases would result in an increase in indirect effects on waters of the United States and a loss of functions and services resulting from the isolation and fragmentation of these resources.

2.1.3 Overview of Alternatives Considered in Detail

The alternatives to the Proposed Action evaluated in the 2006 Draft EIR/EIS included: (1) No Action Alternative; (2) Partial Use of Water from IID; and (3) Full Use of Water from IID. These alternatives are carried forward for supplemental evaluation as necessary to address the federal decisions to be made, current environmental conditions, and regulations. The full range of alternatives described in Section 2.2 are listed below. Alternatives 3 through 8 are based on the Proposed Action but modify certain project components. The effects analyses are limited to those changes associated with the alternative itself.

 Alternative 1: Proposed Action  Alternative 2: No Action  Alternative 3: Partial IID Water Supply Alternative  Alternative 4: Full IID Water Supply Alternative  Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative  Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative  Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative  Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative

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The Preferred Alternative selected by the federal agencies could therefore be one of the above alternatives or a combination of components of multiple alternatives.

2.1.4 Features Common to All Alternatives

Quarry Operations. Surface quarrying methods as described in Chapter 2 of the 2006 Draft EIR/EIS and including relevant BMPs listed in this document’s Section 2.1.5 are common to all of the Action Alternatives considered. Quarrying operations would be conducted under the Proposed Action and its alternatives in accordance with the County-approved Mine and Mine Reclamation Plans and a BLM-approved Plan of Operations (see Appendix D). Currently permitted quarrying activities would continue at the maximum production of 1.92 million tons per year until the resource is exhausted.

Plant Operations. The supply of raw gypsum to the Plant and the operations at the Plant itself are the same as described in the 2006 Draft and 2008 Final EIR/EIS. The Proposed Action and its alternatives include no changes to the current Plant operations. The Plant is located entirely on private land and is not known to impact any areas of federal jurisdiction. No federal decisions are required involving operations at the Plant.

Quarry Reclamation Techniques. Certain aspects of reclaiming disturbed quarry areas under all alternatives would occur using the same techniques as described in the currently approved Mine Reclamation Plan. Where feasible, reclamation would occur concurrently during mining operations. Following the removal of gypsum, the disturbed areas would be reclaimed to a state of natural open space. The steepest portion of the hillside quarries would be sloped no steeper than 1H:1V (Horizontal:Vertical) slopes and about 100 feet high. The site access on the north would remain gated. The privately held lands would not be open to public recreational use. The benched hillsides would be recontoured by blasting or dozing the benches to soften the topography.

Once quarrying operations are terminated, equipment and structures would be removed; their foundations would be reduced below grade and covered in place. It is likely that an office or trailer would remain on site for ongoing revegetation monitoring, and for security purposes. The access road would be maintained for access to the main process area site and specific haul roads would be maintained to access reclamation activity and monitoring. Those portions of the rail line at natural surface elevation would remain in place. The length of rail proceeding below original ground line under the rock storage building will be removed and the spur cut backfilled. Ultimately all equipment, power poles, and buildings would be removed, road access would be restricted by gates, warning signs would be posted, and access to Quarry benches would be blocked by berms and/or boulders.

Revegetation: Revegetation of the mined areas occurs as described in the approved Mine Reclamation Plan. The Revegetation Plan element of the Reclamation Plan focuses on preparing the surface of the mined area and providing native seeds to take advantage of the infrequent rains.

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Revegetation efforts are fully described in the Mine Reclamation Plan and would be varied over the life of the operation. The revegetation techniques are proposed as guidelines that would be followed until new information or techniques become available, which could improve the results of the revegetation activities. Revegetation efforts would use seeds and plants of native species collected locally (on-site and on adjacent areas). The undisturbed portions of the Quarry and areas adjacent to the Quarry provide the targets for achievement through the revegetation effort. The areas to be disturbed by future mining would also provide specimens for direct transplanting of native species, and the undisturbed areas would provide a source of seeds for the revegetation effort.

2.1.5 Best Management Practices (BMPs)

USG has operated mines throughout the United States for over 100 years and has been the operator of the Plaster City Quarry and Plant since 1945. USG has established protocols to meet regulatory requirements and to be good stewards of the land on which it operates. The following BMPs have been in place at the Plaster City facilities for decades.  Dust control measures are based on guidance and strategies presented in the Imperial County 2009 PM10 State Implementation Plan and are included in current permits issued by the Imperial County Air Pollution Control District (ICAPCD). ICAPCD rules are available at http://www.co.imperial.ca.us/AirPollution/index.asp?fileinc=comprules  All vehicles hauling bulk gypsum are covered with tarp or other means.  Mine phases are reclaimed when gypsum reserves have been depleted in accordance with the approved Reclamation Plan.  Quarry mine phases are revegetated as part of reclamation.  Disturbed areas related to pipeline/transmission line removal and construction are reclaimed to pre-construction conditions.  A Spill Contingency Plan/HAZWOPER Model Program is maintained with established emergency response protocols for spills of 55 gallons or more of hazardous material or 5 gallons or more of an extremely hazardous material.  Compliance with existing adopted Mitigation Measures: o USG maintains an integrated weed management plan to control invasive weeds including tamarisk and fountain grass in cooperation with the BLM and County of Imperial. o USG maintains on-call contracts with a Designated Biologist who notifies BLM and USFWS prior to any new ground-disturbing activities and conducts pre-construction clearance surveys.  USG contracts for monitoring with qualified biologists who have authority and responsibility to halt any project activities that violate mandated conservation measures.  The Designated Biologist ensures that no Quarry expansion activity occurs while Peninsular Bighorn Sheep (PBS) are within a 0.25-mile radius of the activity. o The Designated Biologist or Biological Monitor visits the Quarry site periodically to administer the Worker Education Awareness Program and ensure compliance with

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the Integrated Weed Management Plan, the Reclamation Plan, the Wildlife Mortality Reporting Program, and the PBS Monitoring Plan.  To the extent feasible, any new site disturbance is conducted outside the nesting season (January 1 through August 31) to avoid potential take of nesting birds or of eggs.  For project activities in windblown sand habitats on pipeline routes, the Designated Biologist or Biological Monitor is present in each area of active surface disturbance throughout the work day and will examine areas of active surface disturbance for the presence of flat-tailed horned lizard or Colorado fringe-toed lizard.  Speed limits along all access roads (excluding haul roads) will not exceed 15 miles per hour.  Shielded downward-directional lighting on all facilities and infrastructure at night will avoid illumination of adjacent natural areas and the night sky.  Spoils are stockpiled only in previously disturbed areas, or in areas designated for future disturbance (including spoils areas) in the Plan of Operations.  To avoid entrapment of birds during pipeline construction and removal, all pipes or other construction materials or supplies are covered or capped in storage or laydown areas, and checked for secure covering at the end of each work day.  The ends of trenches are left as “escape ramps” to avoid wildlife entrapment.  During pipeline construction, no pipes or tubing of sizes or inside diameters ranging from 1 to 10 inches will be left open either temporarily or permanently.  No anticoagulant rodenticides of any kind are used within the Plant or Quarry areas.  All non-construction, non-mining, and food-related wastes are placed in segregated self- closing raven-proof containers (excluding bulk waste bins) and removed regularly from the site to prevent overflow.  Workers do not feed wildlife.  Pooled rainwater or floodwater within quarries areas is rare due to the fracturing of the gypsum and bedrock and occurs only during major storm events. Water is pumped for use in daily dust control activity which results in avoidance of attracting wildlife to the active work areas.  Any injured or dead wildlife encountered during project-related activities shall be reported to the Designated Biologist, Biological Monitor, California Department of Fish and Wildlife (CDFW), or a CDFW-approved veterinary facility as soon as possible for determining the best course of action. For special-status species, the Designated Biologist or Biological Monitor shall notify the BLM, USFWS, and/or CDFW, as appropriate, within 24 hours of the discovery.  If an active burrowing owl burrow is observed within a work area at any time of year, the Designated Biologist or Biological Monitor, in coordination with BLM, will designate and flag an appropriate buffer area around the burrow where project activities will not be permitted. The buffer area will be based on the nature of project activity and burrowing

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owl activity (i.e., nesting vs. wintering). The Designated Biologist or Biological Monitor will continue to monitor the site until it is confirmed that the burrowing owl(s) is/are no longer present. Owls shall not be harassed to reduce the length of time owls are present in a construction or excavation site.  If avoidance of quarrying or pipeline construction within the buffer area is infeasible, burrowing owls may be excluded from an active wintering season burrow in coordination with CDFW and in accordance with CDFW guidelines, including provision of replacement burrows prior to the exclusion.  USG will be responsible for monitoring and reporting PBS activity in the Quarry area during the life of the project in accordance with a PBS monitoring plan approved by the CDFW and USFWS.

2.2 ACTION ALTERNATIVES INCLUDING PROPOSED ACTION

2.2.1 Alternative 1: Proposed Action

The federal aspects of the United States Gypsum Company Expansion/Modernization Project as described in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS and in the following subsections have not been implemented to date. These activities require federal authorizations. Combined, they constitute the Proposed Action for purposes of this Draft Supplemental EIS.

Plaster City Plant - Water Pipeline Replacement The Proposed Action includes the replacement of an existing 8-inch diameter, Transite water pipeline from USG’s wells in Ocotillo to the Plant, a distance of approximately 8 miles. The replacement pipeline is proposed to improve serviceability, reduce leaks, and reduce maintenance needs due to the age of the existing pipe. Approximately five miles of the pipeline alignment crosses BLM-administered public lands. USG submitted a right-of-way application (case file number CACA-044014) requesting authorization for replacement of the pipeline and any subsequent maintenance within a 30-foot wide area. The new pipeline would be made of high density polyethylene (HDPE) placed in a trench excavated adjacent to the existing pipeline alignment. The excavated soil would be placed adjacent to the trench while the pipeline is being laid and used as backfill once the pipeline is installed. The Proposed Action analyzed in the 2006 Draft EIR/EIS included removal of the existing pipeline after the new line was installed, which remains a part of the Proposed Action.

Quarry - Proposed Quarry Water Supply Pipeline The Proposed Action includes the development of a reliable water supply for the Quarry (see 2006 Draft EIR/EIS Section 2.5.3.1). A new production water well, proposed Well No. 3, would be drilled on USG-owned land (portion of APN 033-020-09); water would be transported to the Quarry via a proposed new pipeline installed alongside the existing alignment of the narrow- gauge railroad to the Quarry facilities. In conjunction with the development of the pipeline, USG would install an electrical service line to serve the well pump.

The proposed utility alignment is located 30 feet north of the centerline of the existing tram road (BLM case file number CALA-040412). USG submitted a right-of-way application (case file

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number CACA 056908) requesting authorization to install subsurface utility improvements, including a water pipeline and a powerline, within a portion of the existing CALA-040412 right- of-way. The total length of utility improvements on both BLM-administered public lands and USG private land is approximately 18,240 lineal feet (see Figure 2-2). Of that length, approximately 10,480 feet would be on BLM-administered public lands. Approximately 10.1 acres of BLM-administered public lands within the existing tram road right-of-way would be temporarily disturbed, based on a 30-foot wide alignment on BLM land.

Quarrying on Public and Private Land Per the 2003 Mine Reclamation Plan, alluvial quarrying activities were proposed on public lands within USG’s PROVIDENCE placer claim; the claim was not patented in 2007 and was withdrawn from the application in 2008. In order to accommodate the Mine Plan design as proposed in the 2003 Mine Reclamation Plan and analyzed in the 2006 and 2008 environmental documents, USG presently proposes three new mill site claims in the former location of the PROVIDENCE claim. Two additional mill site claims along the edge of the Mine Plan boundary where Phases 2, 3, and 3P intersect were filed to correct mapping errors that showed them as private land rather than public lands.

Based on revised land ownership and updated mapping, the Mine Plan includes 15 mill site claims totaling approximately 73.2 acres of public lands. Under the Proposed Action, 11 of these mill sites would be impacted for a total of 9.8 acres of new disturbance on BLM-administered public lands, as outlined, Table 2-1 details the planned disturbance on public lands by mill site.

Ongoing operations of the Quarry per the 2003 Reclamation Plan would also develop approximately 1,118.7 acres of USG’s 2,032.2 acres of private land. In 2003, pursuant to 43 CFR §3809, a Plan of Operations describing all quarrying activities at the Quarry was prepared and submitted to the BLM in consideration of the Proposed Action at the Quarry. The Plan of Operations addressed approximately 408 acres of public lands. The limits of disturbance identified in the 2003 Mine Reclamation Plan and 2003 Plan of Operations have not changed; however, due to changes in land ownership and adjustments to the private land boundary resulting from updated and more precise mapping, the portion of the Mine Plan consisting of public lands has been reduced from 408 acres in 2003 to the present 73.2 acres. Of the 73.2 acres, 1.1 acres in the Annex Mill Site #1 have been impacted by development of the access road; continued development of the Quarry is anticipated to impact approximately 9.8 additional acres. Development of quarrying activities on public lands is subject to BLM approval of a Plan of Operations (September 2003, revised May 2018) in accordance with 43 C.F.R. § 3809.

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Table 2-1 2018 Existing and Planned Disturbance Plaster City Quarry Mine Plan

USG Private Lands BLM Lands Existing Planned New Existing Planned New Disturbance Disturbance Disturbance Disturbance Phase & Areas Acreage Acreage (Approximate (Approximate (Approximate (Approximate Acres) Acres) Acres) Acres) Butte Mill Site 5.0 0.0 0.9

Annex Mill Site #4 5.0 0.0 1.3

Annex Mill Site #3 5.0 0.0 0.3

Cactus Mill Site 5.0 0.0 0.6

Desert Mill Site 5.0 0.0 0.1

Annex Mill Site #1 5.0 1.1 0.0

Peoria Mill Site 3.4 0.0 0.0

Springfield Mill Site 4.8 0.0 0.0

Anchorage Mill Site 5.0 0.0 0.0

Annex Mill Site #2 5.0 0.0 0.0

Mill Site 1 5.0 0.0 0.4

Mill Site 2 5.0 0.0 3.2

Mill Site 3 5.0 0.0 1.8

Mill Site 4 5.0 0.0 0.4

Mill Site 5 5.0 0.0 0.8

TOTALS 1,118.7 436.7 682.0 73.2 1.1 9.8

Alluvial Quarrying and Ephemeral Drainages The Mine Reclamation Plan is divided into phases based on current geological data, quantity and quality of gypsum, market demand and proximity to the existing Plant. Each phase has been numbered for purposes of identification. Figure 2-2 shows the proposed phasing. Figure 2-3 provides a general overview of gypsum deposits included in the Mine Plan. At maximum production rates, the known reserves would provide in excess of 80 years of production. Two types of quarrying are proposed: outcrop quarrying and alluvial wash quarrying. The two methods of quarrying are described below.

Outcrop Quarrying The areas of current production are designated as Quarry 1A and Shoveler. These areas consist of outcrops of gypsum above the level of the alluvial wash. Under the Proposed Action, production would continue with the extension and development of benches with a height of 25 feet. The final configuration of the benches would be based upon: (1) the contact with underlying low-purity gypsum, anhydrite, arkose, or granite; and (2) the up-dip limit of the outcrops. Quarry development would progress to each of the additional phases beginning with Phase 2, then proceeding both north and south into adjacent phases based on proximity and gypsum quality. As previously indicated, overburden on these outcrops is almost nonexistent. When surface clays are encountered they would be removed for use in reclaiming previously mined outcrops.

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Alluvial Wash Quarrying Under the Proposed Action, quarrying would extend north to south. Quarrying of the alluvial wash deposits would progress downward and westward to a maximum overburden depth of 100 feet. Extraction of the gypsum would progress downward from the toe of the overburden strip slope in 25-foot vertical benches at a maximum stable slope of 1H:1V until the bottom of the mineable zone is reached. The depth of each Quarry phase would vary based on the bottom limit of gypsum. For a schematic representation of a typical Quarry development cross-section refer to Figure 2-4.

An earthen berm would be constructed along the west side of the Quarry to divert natural surface water flows toward Fish Creek Wash and away from the Quarry operations. The berm would be dimensioned and located generally as described in section 2.5.3.2 of the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. The design was based on a hydrology study and drainage analysis (Joseph E. Bonadiman & Associates Inc., July 2004). The berm would be 5 feet high, including 2 feet of freeboard, and 20 feet wide. The length would be determined based on the active quarrying phase. For the purpose of analyzing effects, this berm length is assumed to be the entire west side of the quarry along Fish Creek for flood control purposes (estimated to be a maximum of 25,000 feet).

The berm would be constructed of overburden material from various gypsum mining phases, or portions of phases, in the alluvial wash stripped to expose the gypsum. As overburden is stripped, a portion would be pushed to the east bank of the wash and the furthest southern limits of the planned disturbance to form the berm. Another berm consisting of the top 1 foot of surface alluvium would be pushed over the west Quarry slopes and used as surface soil upon reclamation. Remaining overburden may be stockpiled for a short period of time but would typically be pushed into the adjoining mined out areas for reclamation of the slopes such that overburden from Phase 3 would be used in Phase 2, overburden from Phase 4 would be used in Phase 3, and so forth. At end of the quarry life, all berms will have been used for Reclamation.

Quarry Reclamation Following the removal of gypsum, the disturbed areas would be reclaimed to a state of natural open space consistent with the reclamation activities summarized in Section 2.1.4 above and described in detail in the current Plan of Operations (see Appendix D).

2.2.2 Alternative 2: No Action Alternative

Under the No Action Alternative, no element of the Proposed Action would be authorized or implemented. The proposed Quarry water pipeline and electric supply line would not be installed. The existing Plant water supply pipeline would not be replaced. The Quarry would not be expanded onto lands subject to a CWA Section 404 permit or authorization from the BLM under a Plan of Operations. The BLM would deny the right of way applications and the USACE would deny the CWA Section 404 permit. The permitted Quarry and the existing Plant water supply pipeline would continue to operate under current conditions.

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2.2.3 Alternative 3: Partial IID Water Supply Alternative

Alternative 3 is as the same as the Proposed Action, except that a portion of the water needed for Plant operations would be supplied by irrigation water from the IID Westside Main Canal, located 5.5 miles east of the Plant site (see Figure 2-5).

Under this alternative, a new water pipeline would be constructed from the Westside Main Canal to the Plant. The pipeline would be constructed within an alignment currently proposed to be either on the north side of the Union Pacific Railroad, or the north or south side of Evan Hewes Highway. The alignment for the pipeline would be a total area of impact of 30-feet wide (for trenching) and approximately 5.5 miles long.

The IID adopted Resolution No. 8-2006 to include the USG Plant within the boundaries of the IID under its All-American Canal Contract. The inclusion of the USG Plant into the IID would allow the IID to supply water to the Plant. HDPE pipe would be used as it is a very flexible pipe material, especially at smaller diameters, and can accommodate horizontal or vertical variations of as much as 30 feet. When properly welded, the connections are as strong as the rest of the pipe sections. After a long section of pipe has been welded, operators use heavy equipment to lift/push the pipe into the trench. The HDPE pipeline would also require approximately 12 air relief valves. USG intends to use the spoils to backfill the trench based on soil tests conducted by NV5 Engineering in May 2015 between the Plant and the West Main Canal which confirm the suitability of the soils for this purpose.

Water from IID would be blended with water from Ocotillo as needed to achieve the level of water quality and consistency necessary for use in manufacturing wallboard. As stated below, the quality of Colorado River water varies over time. Thus, the amount of water that USG would need to extract from the well at Ocotillo would vary over time. Per the 2016 IID Resolution, the canal water supplied to USG is not to exceed 1,000-acre feet per year and is for use exclusively at the Plant and in accordance with all applicable rules, rates, and regulations of the IID.

In addition to the pipeline itself, this alternative would require a new pumping station near the canal and new water storage facilities at the Plant. An intake structure would be installed at the canal bank and canal water would be delivered approximately 320’ to the west to a pump house structure approximately 22’ wide by 24’ long. Three 50-horsepower pumps would deliver approximately 400 acre-feet/year of canal water to the Plant. The canal intake structure would permanently impact 0.001 acres of waters of the United States and would require a Section 404 Permit under the Clean Water Act from the USACE. The pump station would be accessible from existing roads.

The preliminary design of storage facilities at the Plant includes two ponds constructed on 0.7 acres each to settle out silt and other insoluble solids from the canal water. The ponds would be approximately 175’ x 175’, 4 to 10 feet deep, and have a total capacity of 1,800,000 gallons. They would be constructed at the Plant on USG-owned property. The ponds are anticipated to require a liner to prevent the potential migration of salts (dissolved solids) from the canal water to the underlying groundwater. It is also anticipated that the ponds would be covered with bird netting or floating ballast balls to minimize bird attraction. Fencing around the settling ponds,

U.S. Gypsum Draft SEIS 2-13 July 2019 Chapter 2: Proposed Action and Alternatives

would be constructed to minimize access by humans and wildlife; below-ground wire mesh would prevent burrowing animals from accessing the ponds. After silt and solids settling, water would be piped to two above-ground steel storage tanks for blending with water from Ocotillo; each tank would have a capacity of approximately 585,000 gallons.

Maintenance would be conducted at the ponds to remove and legally dispose of sludge. It is estimated that this would occur approximately three times per year and each event would require a scraper, loader, and up to five 30-mile (round trip) truck trips.

2.2.4 Alternative 4: Full IID Water Supply Alternative

This alternative is the same as Alternative 3, except that all of the water needed for Plant operations would be replaced with irrigation water from the IID Westside Main Canal (see Figure 2-5) through a new pipeline as described in Alternative 3 above. The existing pipeline between Ocotillo and the plant would be removed and not replaced. Additional water treatment facilities would be necessary to achieve the water quality standards USG requires to manufacture its products, including reverse-osmosis units, booster pumps, four water storage tanks, and four evaporation ponds totaling approximately 5 acres. The treatment plant would be designed to federal, State, and County standards.

This alternative does not meet the applicant’s objectives because IID canal water quality does not meet the gypsum processing requirements and would require more extensive treatment and/or blending with water from another, unspecified source.

2.2.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative

Alternative 5 is the same as the Proposed Action except that Phase 10 would not be mined to its full capacity and Phase 10P would be eliminated entirely from the proposed mining plan in order to reduce losses of waters of the United States. USG would reduce the mining depth in Phase 10, grading north to the base grade of Fish Creek (Figure 2-6). Phase 10P is considered for elimination given its position in the northernmost end of the Quarry watershed, its close proximity to Fish Creek, and the relatively low quantity of gypsum ore that would be extracted from this phase compared to other phases in the mining plan.

Under this alternative, the stormwater berm would be eliminated south of Phase 2. Instead, the natural topography of the upper Quarry watershed would direct surface water away from Phases 6 through 9. Using natural landforms would reduce the length of the berm by 1 mile compared with the Proposed Action and would eliminate the need for a complex system of transverse levees with anchored berms in the upper Quarry watershed. The stormwater berm would begin west of Phase 2, where only one transverse levee would be required, and would extend northward through Phase 10.

Phase 10 mining would occur as proposed to a reduced depth connecting with Phase 10P and progressing at an angle suitable to maintain gravity flow. A conveyance channel roughly 200 feet wide would result at the northernmost boundary of Phase 5, extending north through Phases 10

July 2019 2-14 U.S. Gypsum Draft SEIS Chapter 2: Proposed Action and Alternatives

and 10P until its confluence with Fish Creek. Approximately 5.4 million tons less gypsum ore would be mined under this alternative than under the Proposed Action. Compared with the maximum permitted production of 1.92 million tons per year, this alternative would reduce the projected mine life by 2.81 years.

2.2.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative

Alternative 6 is the same as the Proposed Action except that the mining footprint along the western boundaries of Phases 4 and 5, where Annex Mill Site #4 encroaches into an unnamed ephemeral wash, would be reconfigured to reduce losses of waters of the United States (Figure 2-7). Phases 4 and 5 were selected for reconfiguration because of their close proximity to existing administrative/office facilities, where blasting is not ideal due to noise and the depth of overburden needing to be stripped in order to mine the gypsum ore. The stormwater berm would be configured as described for Alternative 5 except that it would be modified to exclude the eliminated portions of Phases 4 and 5, include Phases 10 and 10P, and extend northward from Phase 2 through the northern limit of Phase 10P.

This alternative would reduce the amount of gypsum ore mined by approximately 11.87 million tons. Compared with the maximum permitted production of 1.92 million tons per year, this alternative would reduce the projected mine life by 6.18 years.

2.2.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative

Alternative 7 is the same as the Proposed Action but Phases 2P, 3P(North) and 3P(South) would be eliminated from the proposed mining plan to reduce losses of waters of the United States. As shown in Figure 2-8, the proposed stormwater berm would be modified to exclude the eliminated phases, include Phases 10 and 10P, and extend through the northern limit of Phase 10P.

The amount of gypsum ore mined under this alternative would be approximately 2.33 million tons less than under the Proposed Action. Compared with the maximum permitted production of 1.92 million tons per year, this alternative would reduce projected mine life by 1.21 years.

2.2.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative

Alternative 8 is the same as the Proposed Action except that the mining footprint in Phases 7 and 8 would be reconfigured to reduce losses of waters of the United States (Figure 2-9). Under this alternative, the mining boundaries of Phases 7 and 8 would be moved east parallel with the main drainage channel (Figure 2-9). The stormwater berm would be as described for Alternative 5, but would include all of Phases 10 and 10P.

The overall mining footprint would be reduced by 34 acres, thereby decreasing potential mining beneath the valley alluvium where gypsum ore has been determined to be most abundant. The amount of gypsum ore mined under this alternative would be approximately 13.04 million tons less than under the Proposed Action. Compared with the maximum permitted production of 1.92 million tons per year, this alternative would reduce projected mine life by 6.79 years.

U.S. Gypsum Draft SEIS 2-15 July 2019 Chapter 2: Proposed Action and Alternatives

2.3 COMPARISON OF ADVERSE EFFECTS BY ALTERNATIVES

Table 2-2 presents a summary of the adverse effects identified as a result of the analyses provided herein for the Proposed Action and each of the Alternatives.

The analyses in this Draft Supplemental EIS include the mitigation measures adopted under CEQA as presented in the Summary section of the 2006 Draft EIR/EIS, Table S-1 and as revised in the Executive Summary of the 2008 Final EIR/EIS, Table ES-1. Additional mitigation measures developed to mitigate adverse effects associated with new information provided in this Draft Supplemental EIS are listed in Appendix E.

The mitigation measures for impacts determined significant under CEQA associated with the use of Ocotillo/Coyote Wells Groundwater Basin (e.g., Mitigation Measures 3.3-1 and 3.3-2) were the subject of litigation under CEQA in 2014. In response to the Superior Court Order, the two mitigation measures previously adopted by the Imperial County Board of Supervisors are being rescinded and revised mitigation measures are under consideration. These revised mitigation measures relate specifically to the use of groundwater and are outside the scope of the NEPA review.

2.4 Preferred Alternative

2.4.1 Federal Lead Agency (BLM) Preferred Alternative

The preferred alternative is a preliminary indication of the responsible federal official’s preference of action selected from among the Proposed Action and its alternatives. The preferred alternative may be selected for a variety of reasons, such as the priorities of the particular lead agency, in addition to the environmental considerations. In accordance with NEPA (40 CFR 1502.14(3)), the BLM has identified the preferred alternative as Alternative 3, the Partial IID Water Supply Alternative.

2.4.2 USACE Least Environmentally Damaging Practicable Alternative

USEPA provides guidelines for processing permits under Section 404 of the Clean Water Act (Section 404(b)(1) Guidelines (40 CFR 230). These guidelines state that no discharge of dredged or fill material shall be permitted if it causes or contributes to violations of any applicable State water quality standard (40 C.F.R. 230.10(b)(1)), violates any applicable toxic effluent standard or prohibition (40 C.F.R. § 230.10(b)(2)), jeopardizes the continued existence of any endangered or threatened species or destroys or adversely modifies its critical habitat (40 C.F.R. § 230.10(b)(3)), or causes or contributes to significant degradation of waters of the United States (40 C.F.R. § 230.10(c)).

The alternatives in this Supplemental EIS include a range of alternatives for modifying the quarry operations to reduce impacts to watersheds. These alternatives are presented in Chapter 2 as Alternatives 5 through 8.

In conformance to the USEPA guidelines, the USACE will screen and analyze the project alternatives for practicability based on achieving the overall project purpose, logistics, and environmental criteria. Based on the analysis, the USACE will identify the Least Environmentally Damaging Practicable Alternative (LEDPA) from among the alternatives.

July 2019 2-16 U.S. Gypsum Draft SEIS Chapter 2: Proposed Action and Alternatives

Table 2-2 Comparison of Effects by Alternative Alternative 5: Alternative 6: Alternative 7: Alternative 8: Lower Quarry Lower Quarry Middle Quarry Upper Quarry Watershed Watershed Watershed Watershed Alternative 1: Alternative 2: Alternative 3: Alternative 4: Reduced Mining Reduced Mining Reduced Mining Reduced Mining Proposed Action No Action Partial IID Water Full IID Water Footprint A Footprint B Footprint Footprint Resource Alternative Alternative Supply Alternative Supply Alternative Alternative Alternative Alternative Alternative Geology/Mineral 140 million tons of 2 million tons of Same as Alternative 1 Same as Alternative 1 5 million tons less 11 million tons less 2 million tons less 13 million tons less Resources/Paleontology gypsum mined over 73 gypsum mined gypsum mined than gypsum mined than gypsum mined than gypsum production years over approx. 1 year Alternative 1 over 70 Alternative 1 over 67 Alternative 1 over 72 than Alternative 1 over years years years 66 years Hydrology & Water  Jurisdictional waters No new impacts on  Jurisdictional waters  Same effects as  Jurisdictional waters  Jurisdictional waters  Jurisdictional waters  Jurisdictional waters Quality affected hydrology or water affected Alternative 3 affected affected affected affected o 134 acres of losses quality o 134 acres of losses  Eliminates use of o 118 acres of losses o 125 acres of o 122 acres of o 127 acres of losses in quarry in quarry sole-source aquifer in quarry losses in quarry losses in quarry in quarry o 1.8 acres o 11 acres o 1.8 acres o 1.8 acres o 1.8 acres o 1.8 acres temporary impacts temporary, 0.001 temporary impacts temporary temporary temporary impacts within waterline acre permanent within waterline impacts within impacts within within waterline alignments impacts within alignments waterline waterline alignments  1 new well installed waterline  1 new well installed alignments alignments  1 new well installed alignments  1 new well installed  1 new well installed  1 new well installed  Reduces use of sole- source aquifer Vegetation & Wildlife  Long-term No new effect on  Same effects as Same effects as  Same overall effects  Same overall effects  Same overall effects  Same overall effects disturbance of about wildlife or Alternative 1 Alternative 3 as Alternative 1 as Alternative 1 as Alternative 1 as Alternative 1 695 acres of native vegetation  20 acres of added  Reduced habitat  Reduced habitat  Reduced habitat  Reduced habitat vegetation and habitat effects for impact due to impact due to impact due to impact due to wildlife habitat IID canal pipeline. reduced mining reduced mining reduced mining reduced mining  615 acres of Peninsular bighorn sheep critical habitat affected (15 acres on public lands)  Potential take or disturbance to special-status bats, American badger,

U.S. Gypsum Draft SEIS 2-17 July 2019 Chapter 2: Proposed Action and Alternatives

flat-tailed horned lizard  Potential disturbance (but not take) of barefoot banded gecko, Peninsular bighorn sheep, flat- tailed horned lizard, burrowing owl, and other protected birds. Air Quality Annual emissions at or Decreasing Same annual Same annual Same annual Same annual Same annual Same annual below De Minimis emissions as emissions as for emissions as for emissions as emissions as emissions as emissions as Rates4 over 73-year previously Alternative 1 Alternative 1 Alternative 1 but over Alternative 1 but over Alternative 1 but over Alternative 1 but over mine life disturbed lands 3-year shorter mine 6-year shorter mine 1-year shorter mine 7-year shorter mine recover surface life life life life stability over time and no new disturbance occurs; 72-year shorter mine life Cultural Resources Two prehistoric sites No adverse effects. Same effects as Same effects as Same effects as Same effects as Same effects as Same effects as adversely affected Alternative 1 Alternative 1 Alternative 1 Alternative 1 Alternative 1 Alternative 1 Special Designations 18.21 acres of new No effects on 27 acres of new Same effects as Same effects as Same effects as Same effects as Same effects as surface disturbance in special land use surface disturbance in Alternative 3 Alternative 1 Alternative 1 Alternative 1 Alternative 1 the Yuha Basin ACEC designations the Yuha Basin ACEC Recreation Short-term, temporary No impact on Short-term, temporary Same effects as Same effects as Same effects as Same effects as Same effects as limitations on public recreation limitations on public Alternative 3 Alternative 1 Alternative 1 Alternative 1 Alternative 1 access while access while constructing 2 water constructing 3 water lines lines Socioeconomics &  Increased ability to No new effect  Same effects as Same effects as Same effects as Same effects as Same effects as Same effects as Environmental Justice respond to future Alternative 1 Alternative 3 Alternative 1 but over Alternative 1 but over Alternative 1 but over Alternative 1 but over market demand  Short-term 2- year shorter mine 6- year shorter mine 1- year shorter mine 7- year shorter mine  140 potential new employment life life life life jobs increase  Increased consumer constructing IID spending pipeline

4 De Minimis rates established to demonstrate General Conformity with the CAA.

July 2019 2-18 U.S. Gypsum Draft SEIS Chapter 3: Affected Environment

3.1 INTRODUCTION

3.1.1 Chapter 3 Overview

This chapter describes the existing conditions of BLM resource programs, resource uses, special designations and the social and economic environment on or near the project site. The description of the affected environment uses the best and most recent data available. The existing conditions provide the baseline to which the potential impacts of the Proposed Action and its alternatives were compared.

This chapter describes the environmental consequences, or impacts, that are expected to occur as a result of implementing the project. The impacts were analyzed to a level of detail consistent with the availability and quality of data to support the analyses. Where quantitative information was available, a quantitative analysis was conducted; however, if quantitative data were not available, a qualitative analysis was conducted.

The affected environment of the project was analyzed in Sections 3.0 and 4.0 of the 2006 Draft EIR/EIS, and is presented for each resource in Chapter 3 of this document. Supplemental data were obtained from updated technical studies and field surveys, the current CDCA Plan, as amended, the DRECP, other applicable BLM planning documents, and NEPA documents. The affected environment is limited to those potential impacts resulting from updated information and changes in circumstances that may have occurred since the 2006 Draft and 2008 Final EIR/EIS were published.

3.1.2 Resources Not Considered

This chapter does not provide detail about environmental components that are not present and therefore would not be affected by the project. These include: 1) Livestock Grazing; and 2) Cave and Karst Resources.

3.1.3 Impact Analysis Methodology

Impacts on environmental resources in the project area were analyzed by determining the effects that would occur on a given resource if the Proposed Action or any of its alternatives were implemented. The specific methodologies used are presented, as applicable, within each resource subchapter. Both direct and indirect impacts were analyzed.

Terms referring to the intensity, context (geographic extent), and duration of impacts used in this chapter are defined below. Impacts are not necessarily negative; positive impacts are also identified.

 Adverse – the effect is negative.  Beneficial – the effect is positive.  Negligible – the effect is at such a low level that a change would be hard to detect.  Minor – the effect is slight but detectable; there would be a small change.

U.S. Gypsum Draft SEIS 3.1-1 July 2019 Chapter 3: Affected Environment

 Moderate – the effect is readily apparent; there would be a measurable change that could result in small but permanent change.  Temporary – the effect occurs only during implementation of a management action.  Short-term – the effect occurs only for a short time after implementation of a management action.  Long-term – the effect occurs for an extended period after implementation of a management action.  Permanent – the effect is irreversible; the resource would never revert to current conditions.  Direct – effect that occurs as a result of actions on the resource being addressed.  Indirect – effect caused by the action and is either later in time or farther removed in distance, but is still reasonably foreseeable. .  Cumulative – the result of incremental impacts of actions when added to past, present or reasonably foreseeable future actions.

The Cumulative Projects List located in Appendix F provides a comprehensive listing of all present and foreseeable projects that could contribute to a cumulative impact on the environment regardless of entity (federal, State, County, etc). The list presents the project name, corresponding identification number, location, type, status, total acres, and a brief description of each project, to the extent available. Most of the projects listed have been, are being, or would be required to undergo their own independent environmental review under NEPA or CEQA or both, as applicable. The yellow (10 mile) circles, green (20 mile) circles and red (30 mile) circles represent radii surrounding both the Quarry and Plant. Any project outside of a specific radius is marked with an (*) to signify it is outside of the geographic scope of analysis. The critical habitat of the Peninsular bighorn sheep (PBS) is also shown on the exhibit.

The relevant geographic scope of analysis of cumulative impacts is identified for each resource within each subsection of Chapter 3. Each project in a region would have its own implementation schedule, which may or may not coincide or overlap with the implementation of this project. This is a consideration for short-term impacts. The cumulative analysis assumes that all projects in the cumulative scenario would be built and operated during the operating lifetime of this project.

July 2019 3.1-2 U.S. Gypsum Draft SEIS Chapter 3.2: Geology/Mineral Resources/Paleontology

3.2 GEOLOGY/MINERAL RESOURCES/PALEONTOLOGY

The effects of the Proposed Action and its alternatives relative to Geology, Mineral Resources, and Paleontology were analyzed in Sections 3.2 (Geology) and 4.2 (Irreversible and Irretrievable Commitment of Resources) of the 2006 Draft EIR/EIS. This section addresses new information available since publication of the Draft and Final EIR/EIS, any new effects of the Proposed Action and its alternatives on these resources within the affected environment, and any effects that were not analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

3.2.1 Affected Environment

The affected environment of the Proposed Action and its alternatives was presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. The Quarry and Plant are both located in southeast California, in the western portion of Imperial County within the Colorado Desert, which lies at relatively low elevations, in some places below sea level. The western portion of Imperial County is characterized by a series of low-lying mountains associated with the Peninsular Range, opening up to the Imperial Valley and Salton Trough to the east. The geology in the Quarry area consists primarily of nearly pure beds of Miocene-age gypsum. The gypsum beds are part of a conformable sequence consisting of Miocene non-marine Split Mountain Formation (also referred to as the Split Mountain Group), Fish Creek Gypsum, and Pliocene marine Imperial Formation (also referred to as the Imperial Group), which are unconformably underlain by Mesozoic intrusive igneous rocks. Changes in the regional or project area geology have not occurred since the 2006 Draft EIR/EIS, but the information described in that document is updated herein.

The BLM prepared a Mineral Report in 2000 as part of a mineral patent application submitted by USG. The report concluded that the portion of the gypsum deposits on public lands constituted a valuable mineral reserve. This report further recommended that the mineral patents proceed forward to patenting. Eighteen placer mining claim patents were granted in 2008 (Patent No. 04- 2008-0010; also refer to Chapter 2.0), transferring into private ownership 304.57 acres of placer mining claims previously identified as public land in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. These claims are no longer subject to regulatory review by the BLM for purposes of mineral extraction. Other aspects of the affected environment related to mineral resources and described in the previous documents are still accurate and have not changed.

Fifteen active mill site claims remain at the Quarry and are subject to regulatory compliance and review by the BLM.

Paleontology: Geologic mapping indicates that the area researched for the Proposed Action and its alternatives within a half-mile of the project is underlain by Mesozoic-age or older, undivided intrusive igneous rocks (gr); Miocene-age Split Mountain Group Red Rock Formation (Tsr), and Elephant Trees Formation (Tse); Pliocene- to Miocene-age Fish Creek Gypsum (Tfc); Pliocene- to Miocene-age Imperial Group, Latrania Formation (Til), and undivided (Ti); Pleistocene- to Pliocene-age Palm Spring Group, undivided (QTp); Holocene-age Lake Cahuilla beds (Qlc); Holocene-age alluvial terrace deposits (Qt); and Holocene-age alluvium, undivided (Qa). See

U.S. Gypsum Draft SEIS 3.2-1 July 2019 Chapter 3.2: Geology/Mineral Resources/Paleontology

Appendix G for the distribution of the geologic units associated with the Proposed Action (Paleo Solutions, May 15, 2018).

Because of their nature and origin, the geologic units at the Quarry are not expected to contain significant paleontological resources (2006 Draft EIR/EIS). Paleontological surveys were recommended in the areas of the proposed water supply pipeline, but they were not performed prior to publishing the 2006 Draft or 2008 Final EIR/EIS.

The 2018 study by Paleo Solutions determined that the Quarry, the proposed new water line supplying the Quarry, and the existing water line to the wells in Ocotillo are mostly underlain by geologic units with unknown, very low, or low paleontological potential. Areas of high paleontological potential lie within a mile of the west and southwest portions of the Quarry boundary and existing water line. One segment of the existing water line supplying the Plant and one segment of the proposed water line to supply the Quarry intersect with mapped higher- potential deposits. The 2018 study recommended paleontological surveys and confirmation of mapping in areas where pipeline construction-related ground disturbance would occur, and that a plan be prepared to provide recommendations for monitoring and worker training, and in the event of a discovery, for the implementation of recovery, analysis, curation, and notification protocols.

3.2.2 Methodology

The methodology for analyzing the effects of the Proposed Action and its alternatives on geology and mineral resources is the same as discussed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS for the Quarry. Activities associated with Quarry expansion and operations, water line construction and ongoing maintenance identified from the Applicant’s Plan of Development and Plan of Operations were evaluated to determine their potential to affect the existing conditions.

Slope Stability. The stability of slopes is reviewed and approved by Imperial County and the Department of Conservation, Division of Mine Reclamation during the surface mine and reclamation permit process. Working slopes (operating quarry benches) and finished slopes (reclaimed) are inspected and monitored annually. Slopes are evaluated for gross and surficial stability under both static and seismic conditions. In addition to conducting quantitative analyses, the slopes are visually evaluated by a qualified geologist for erosion, over-excavation, and signs of adverse geologic conditions. The existing physical slopes of the mine’s current operations are inspected annually. This typically includes slope angle, erosion, bench location, height, and width. Review of the inspection reports was conducted to determine any change in conditions that may result in adverse effects associated with the Proposed Action and its alternatives.

Paleontology. The 2006 Draft EIR/EIS and 2008 Final EIR/EIS identified no potential for paleontological resources associated with the Quarry activities under the Proposed Action. However, the alignments of water pipelines associated with the alternatives were not evaluated. A Paleontological Technical Study prepared by Paleo Solutions dated May 15, 2018, updated the previous work with current data reviews, and included the area to be affected by the Proposed Action and its alternatives (referred to as “project area”). The report is included as Appendix G to this Draft Supplemental EIS and is summarized herein.

July 2019 3.2-2 U.S. Gypsum Draft SEIS Chapter 3.2: Geology/Mineral Resources/Paleontology

The BLM assigns geologic units a Potential Fossil Yield Classification (PFYC) class based on the probability and abundance of known vertebrate fossils and scientifically significant invertebrate and plant fossils. The PFYC scheme ranges from very low (PFYC 1) to very high (PFYC 5) depending on the potential fossil yield. Unknown fossil potential (PFYC U) is assigned to geologic units that do not have a clear PFYC assignment. Typically, paleontological resource compliance is required for earthwork occurring within PFYC classes 3, 4, 5, or U rock units. The BLM identified that portions of the project area are underlain by geologic formations assigned a class of PFYC 3, 4, and U.

3.2.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals

Since the 2006 Draft EIR/EIS and 2008 Final EIR/EIS were prepared there have been no changes to applicable regulations, plans or policies/management goals that affect mineral resources, including slope stability. There has been one change to laws related to Paleontological Resources.

Paleontology: Paleontological Resources Preservation Act (PRPA): Title VI, Subtitle D in the Omnibus Public Lands Act of 2009, Public Law 111-011 was signed into law on March 30, 2009 (Public Law 111-11, Title VI, Subtitle D; 16 U.S.C. §§ 470aaa - 470aaa-11). PRPA directs the Department of Agriculture (U.S. Forest Service) and the Department of the Interior (National Park Service, Bureau of Land Management, Bureau of Reclamation, and Fish and Wildlife Service) to implement comprehensive paleontological resource management programs. With passage of the PPRA, Congress officially recognizes the importance of paleontological resources on federal lands by declaring that fossils from federal lands are federal property that must be preserved and protected using scientific principles and expertise. The PRPA provides: 1) uniform definitions for “paleontological resources” and “casual collecting”; 2) uniform minimum requirements for paleontological resource use permit issuance; 3) uniform criminal and civil penalties for illegal sale and transport, and theft and vandalism of fossils from federal lands; and 4) uniform requirements for curation of federal fossils in approved repositories.

3.2.4 Direct and Indirect Effects

3.2.4.1 Alternative 1: Proposed Action

The Proposed Action is described in detail in Chapter 2. All proposed phases of the Quarry would be mined, a berm would be constructed along the west side of the Quarry, a new water pipeline and electrical line for the Quarry water supply and the existing water line supplying the Plant would be authorized, and the existing waterline would be removed and replaced.

The active use of the gypsum mineral resources has not changed since the prior analysis. The existing, permitted gypsum quarry was reviewed for compliance with federal, State, and local surface mining and reclamation regulations, and was determined to be in compliance.

The potential effects of the Proposed Action on Mineral Resources has not changed since the previous environmental documents were prepared. The land ownership of portions of the Quarry has changed through the grant of patents (Patent No. 04-2008-0010; refer to Chapter 2.0). These

U.S. Gypsum Draft SEIS 3.2-3 July 2019 Chapter 3.2: Geology/Mineral Resources/Paleontology grants transferred 304.57 acres of placer mining claims previously identified in the 2006 Draft and 2008 Final EIR/EIS as public lands. The claims on the patented lands are no longer subject to regulatory review by the BLM for purposes of mineral extraction.

The 2006 Draft EIR/EIS and 2008 Final EIR/EIS identified two areas of potential effects from the Proposed Action related to slope stability and paleontology.

Paleontology. The 2018 Paleontological Technical Study (Appendix G) indicated that portions of the Quarry are underlain by a formation that may be sensitive for paleontological resources: the Miocene-age Split Mountain Group, Elephant Trees Formation (PFYC U). However, ground disturbing activities of the Proposed Action at the quarry operation would only be associated with the mining of gypsum and would not extend into the boulder conglomerate formation (refer to Appendix D – Plan of Operations). Therefore, the Proposed Action would not affect any potential paleontological resources within the Quarry. The proposed waterline replacement between Ocotillo and the Plant was determined in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS not to have an effect on paleontological resources. The 2018 Paleontological Technical Study, however, identified that the Pleistocene-age Palm Springs Group (PFYC 4) underlies a portion of the pipeline. Additionally, the Holocene-age Lake Cahuilla Beds (PFYC 3) underlie a small portion of the area analyzed for the Well No. 3 water pipeline. Both of these geologic units are sensitive for paleontological resources. Excavations, grading, and other earthmoving activities have the potential to result in significant adverse effects to paleontological resources in geologic units determined to have a moderate to high potential for fossil yield. Mitigation Measure 3.2-3 would be implemented (see Section 3.2.6 below).

3.2.4.2 Alternative 2: No Action Alternative

The details of the alternative have not changed and the alternative’s effect on geology and mineral resources is the same as was disclosed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

Slope Stability. Slope stability activities associated with quarrying would not affect paleontological resources because ground disturbing activities are limited to the mining of

July 2019 3.2-4 U.S. Gypsum Draft SEIS Chapter 3.2: Geology/Mineral Resources/Paleontology gypsum and are not proposed in areas where paleontological resources are typically found (refer to Appendix D – Plan of Operations)

Paleontology. With the No Action Alternative, paleontological resources would not be disturbed, and further mitigation would not be required.

3.2.4.3 Alternative 3: Partial IID Water Supply Alternative

Alternative 3, described in detail in Chapter 2, is the same as the Proposed Action except that the processing water would be partially replaced with irrigation water from the IID Westside Main Canal and new settling ponds for treating the IID water would be constructed on USG-owned lands at the Plant. This alternative was analyzed and presented in the 2006 Draft EIR/EIS and the 2008 Final EIR/EIS. The details of the alternative have not changed and the alternative’s effect on geology and mineral resources is the same as was disclosed in those earlier documents.

Paleontology. The 2006 Draft EIR/EIS and 2008 Final EIR/EIS identified a potential for loss of paleontological resources with respect to the construction an IID Water Supply pipeline (Sections 3.2.3.4 and 3.2.3.5) and provided Mitigation Measure 3.2-2. This mitigation measure required surveying the proposed water line location, and adopting recommendations resulting from those surveys. The 2018 Paleontological Technical Study (Appendix G) identified that this alternative pipeline is underlain by the Holocene-age Lake Cahuilla Beds which is known to have a moderate potential (PFYC 3) for paleontological resources.

The 2018 Paleontological Technical Study of the proposed waterline replacement between Ocotillo and the Plant identified that a portion of the pipeline is underlain by the Pleistocene-age Palm Springs Group known to have a high sensitivity (PFYC 4) for paleontological resources. Excavations, grading, and other earthmoving activities have the potential to result in significant adverse effects to paleontological resources in formations determined to have a moderate to high potential for paleontological resources. Mitigation Measure 3.2-3 would be implemented (see Section 3.2.6 below).

3.2.4.4 Alternative 4: Full IID Water Supply Alternative

Alternative 4, described in detail in Chapter 2, is the same as Alternative 3 except that all the water for Plant operations would come from the IID Westside Main Canal and the existing waterline to the Plant would be removed. This alternative was analyzed and presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. The alternative has not changed, and its effect on geology and mineral resources is the same as was disclosed in the earlier documents.

Paleontology. The effects on Paleontology of this alternative would be the same as for Alternative 3. It is possible that the removal of the existing Ocotillo waterline would impact paleontological resources, however Mitigation Measure 3.2-3 presented below would be implemented.

U.S. Gypsum Draft SEIS 3.2-5 July 2019 Chapter 3.2: Geology/Mineral Resources/Paleontology

3.2.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative

Alternative 5, described in detail in Chapter 2 and shown in Figure 2-6, is the same as the Proposed Action but with Phase 10 reduced, Phase 10P eliminated, and the berm modified correspondingly.

Under this alternative, approximately 5.4 million tons less gypsum ore would be mined than under the Proposed Action. At a maximum permitted production of 1.92 million tons per year, this alternative would reduce the projected mine life presented in the Proposed Action by 2.81 years.

Slope Stability. The 2006 Draft EIR/EIS and 2008 Final EIR/EIS identified the potential for slope instability due to Quarry development under the Proposed Action. Alternative 5 would reduce the size and shape of the proposed mine quarry within the phase footprint. Neither the conditions contributing to the potential for slope instability nor the proposed mitigation would change with this alternative. Potential direct impacts from Alternative 5 to quarry slope stability would be reduced by the reduction in proposed slopes from the Proposed Action. Mitigation was proposed in the 2006 Draft EIR/EIS to address potential impacts to resources, as described therein and in this section. No changes to the mitigation are proposed. Mitigation Measures 3.2-1a, 1b, and 1c were proposed to reduce the potential for slope instability at the quarry.

Paleontology. The effects on Paleontology of this alternative would be the same as for the Proposed Action. This alternative would not have the potential for extending mining into the boulder conglomerate formation. Therefore, any potential paleontological resources within the Quarry would not be affected by implementation of Alternative 5.

3.2.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative

Alternative 6, described in Chapter 2 and shown in Figure 2-7, is the same as the Proposed Action except that Phases 4 and 5 would be reconfigured to reduce losses of waters of the United States, and the berm would be modified correspondingly.

July 2019 3.2-6 U.S. Gypsum Draft SEIS Chapter 3.2: Geology/Mineral Resources/Paleontology quarry phase size reduction from the Proposed Action. Mitigation was proposed in the 2006 Draft EIR/EIS to address potential impacts to resources, as described therein and in this section. No changes to the mitigation are proposed. Mitigation Measures 3.2-1a, 1b, and 1c were proposed to reduce the potential for slope instability at the quarry.

3.2.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative

Alternative 7, described in detail in Chapter 2 and shown in Figure 2-8, is the Proposed Action but with Phases 2P, 3P (North) and 3P (South) eliminated from the proposed mining plan and the berm modified accordingly. The amount of gypsum mined under Alternative 7 would be reduced by approximately 2.33 million tons compared with the Proposed Action. At a maximum permitted production of 1.92 million tons per year, this alternative would reduce projected mine life presented in the Proposed Action by 1.21 years.

Slope Stability. The 2006 Draft EIR/EIS and 2008 Final EIR/EIS identified the potential for slope instability due to Quarry development under the Proposed Action. Alternative 7 would reduce the size and shape of the proposed mine quarry within the phase footprint. Neither the conditions contributing to the potential for slope instability nor the proposed mitigation have changed since then. Potential direct impacts to quarry slope stability would be reduced by implementation of Alternative 7 by an equivalent reduction in proposed slope through quarry phase reduction from the Proposed Action. Mitigation was proposed in the 2006 Draft EIR/EIS to address potential impacts to resources, as described therein and in this section. No changes to the mitigation are proposed. Mitigation Measures 3.2-1a, 1b, and 1c were proposed to reduce the potential for slope instability at the quarry.

3.2.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative

Alternative 8, described in Chapter 2 and Figure 2-9, is the Proposed Action but with a reduced mining footprint in Phases 7 and 8. The mining boundaries of Phases 7 and 8 would be shifted east parallel with the existing drainage channel. The overall mining footprint would be reduced by 34 acres, thereby decreasing potential mining beneath the valley alluvium where gypsum ore has been determined to be most abundant. The volume of ore that would be mined over the life of the quarry would be reduced by approximately 13.04 million tons. At a maximum permitted production of 1.92 million tons per year, this alternative would reduce projected mine life presented in the Proposed Action by 6.79 years.

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Slope Stability. The 2006 Draft EIR/EIS and 2008 Final EIR/EIS identified the potential for slope instability due to Quarry development under the Proposed Action. Neither the conditions contributing to the potential for slope instability nor the proposed mitigation have changed since then, nor do those factors apply to this alternative. This alternative would reduce the size and shape of the proposed mine within Phases 7 and 8. The Quarry phase reductions would proportionally reduce the direct impacts associated with the Proposed Action on slope stability. The nature of the project’s potential impacts on slope stability are the same as for the Proposed Action; however, the phase reductions would reduce number of slope failures that could occur.

The 2006 Draft EIR/EIS and 2008 Final EIR/EIS proposed Mitigation Measures 3.2-1a, 1b, and 1c to reduce the potential for adverse impacts of the project on slope stability at the quarry. Those measures would also be applicable to this alternative. No changes to the mitigation are proposed in this Supplemental Draft EIS.

Paleontology. The effects on Paleontology for this alternative would be the same as for the Proposed Action. This alternative would not have the potential for extending mining into the boulder conglomerate formation. Therefore, any potential paleontological resources within the Quarry would not be affected by implementation of Alternative 8.

3.2.5 Cumulative Effects

3.2.5.1 Geographic Scope of the Cumulative Effects Analysis

Table F-1 located in Appendix F provides a comprehensive listing of all present and foreseeable projects that could contribute to a cumulative impact on the environment. Projects listed include those located on BLM-administered lands, or private lands, identified by the BLM and by local governments, such as Imperial County, and the cities of El Centro, Imperial, and Brawley. Table F-1 presents the project name, location, type, status, total acres, and a brief description of each project, to the extent available. Most of the projects listed in Table F-1 have been, are being, or would be required to undergo their own independent environmental review under NEPA or CEQA or both, as applicable. Figure F-1 shows the location of each of the projects listed in Table F-1 using a corresponding identification number. The yellow (10 mile) circles, green (20 mile) circles and red (30 mile) circles represent radius’s surrounding both the quarry and Plaster City Plant. Any project outside of the radius is marked with an (*) to signify it is outside of the boundaries for consideration. Only one project lies within 10 miles of the Quarry, approximately nine are within 10 miles of the Plaster City Plant.

3.2.5.2 Timeframe of the Cumulative Effects Analysis

The timeframe of the cumulative effects analysis is the life of the Proposed Action or its alternatives, estimated at a maximum of 73 years of Quarry operations, an additional 7 years of Plant operations, and an additional estimated 10 years for facilities decommissioning and final reclamation/revegetation.

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3.2.5.3 Past, Present and Reasonably Foreseeable Actions

The cumulative projects considered for this cumulative effects analysis include 54 projects. These projects consist of solar energy farms, cell towers, subdivisions, rights of way, a large water impoundment and one mine. The majority of projects occur within the cities of El Centro and Brawley. Of those on public lands, five involve rights of way for power transmission and one for the creation of a wind energy facility on 12,406 acres of public land. The Proposed Action would not contribute to the geographic scope of this activity or any of the public lands proposed actions listed.

Geology/ Slope Stability. The cumulative projects considered for this cumulative effects analysis would include other nearby projects related to quarrying, mass grading, or other operations that would impact slope stability. There are two mining projects within the effects area of the Quarry. One is a gold mine; the area of its disturbance is unknown. The other is a right of way serving an existing aggregate mine affecting approximately 13 acres. No other past, present, or reasonably foreseeable mining or other applicable projects were found that would affect slope stability or other geologic features within the geographic scope of this analysis. The Proposed Action is the only gypsum mine in Imperial County and the region. There would be no contribution to cumulative extraction of gypsum to the area of effect.

The Proposed Action would not contribute to a cumulative loss of geologic resources within the study area or a cumulative loss of slope stability outside the project area.

Paleontological resources. The Proposed Action and some of its alternatives, as stated above, have the potential to directly affect paleontological resources. Cumulative conditions to paleontological resources involve the loss of non-renewable scientifically important fossils and associated data, and the incremental loss to science and society of these resources over time. Land development projects have resulted in cumulative conditions affecting paleontological resources in the Imperial Valley. The implementation of paleontological mitigation measures during surface disturbing projects has resulted in the salvage and permanent preservation of large numbers of scientifically significant paleontological resources that would otherwise have been destroyed. This has greatly reduced the cumulative effects of such projects on paleontological resources and has resulted in the beneficial cumulative effect of making these fossils available for scientific research and education by placing them in museum collections.

Unknown, unrecorded paleontological resources may be found at nearly any present and future development site located within Pleistocene or older sedimentary geologic deposits within Imperial County. When discovered, paleontological resources are treated in accordance with applicable federal and State laws and regulations as well as with the mitigation measures and permit requirements applicable to a project. Generally, as fossil localities are discovered, they are recorded. If the nature of the resource requires it, the resource is either protected (i.e., avoided) or collected for future research or educational use.

It is not known what paleontological resources, if any, would be affected by development of all present and future projects identified in Appendix F. However, given the density of past development in San Diego and Imperial Counties, and the large number of reasonably

U.S. Gypsum Draft SEIS 3.2-9 July 2019 Chapter 3.2: Geology/Mineral Resources/Paleontology foreseeable projects listed in Appendix F, it is reasonable to assume that resources exist and could be uncovered at multiple sites. Mitigation Measures 3.2-2 and 3.2-3 require that resources discovered during construction of the Proposed Action or its alternatives be protected, thereby reducing impacts. Surveys conducted of the project area in 2018 indicated few if any additional scientifically significant fossils would remain on the ground surface within a project area. Implementation of paleontological mitigation measures during surface disturbance would have the potential to result in the salvage and permanent preservation of large numbers of scientifically significant paleontological resources that would otherwise be destroyed. This would greatly reduce the cumulative contribution of the Proposed Action or its alternative on paleontological resources and would make these fossils available for scientific research and education by placing them in museum collections. Additionally, regulatory standards that provide protections for paleontological resources would reduce potential effects if resources are found during present and reasonably foreseeable projects. Therefore, the effects of the Proposed Action or its alternatives, when combined with effects from past, present and reasonably foreseeable projects would be insignificant with respect to non-disturbance.

3.2.6 Mitigation Measures

Mitigation was proposed in the 2006 Draft EIR/EIS to address potential impacts of the project on environmental resources, as described therein and in this section. No changes to the mitigation are proposed. Mitigation Measures 3.2-1a, 1b, and 1c were proposed to reduce the potential for slope instability at the quarry.

Paleontological resources surveys were recommended in the 2006 Draft EIR/EIS as Mitigation Measure 3.2-2. Based on the geologic formations identified in the May 2018 Paleontological Technical Study and the Mine Plan of Operations proposal to limit subsurface disturbance to the gypsum outcrops, surveys at the Quarry are not currently recommended. However due to the presence of moderate to high paleontological potential within the areas associated with Quarry Well No. 3 water pipeline ROW, mitigation of potential adverse effects resulting from construction-related ground disturbance is recommended.

Mitigation Measure 3.2-3: Once the pipeline alignment is located and staked, a pre- construction pedestrian field survey is recommended in order to locate any surficial fossil localities and verify the geologic units underlying the area associated with the Proposed Action. For any areas where potential resources cannot be avoided by the pipeline construction, a Paleontological Resources Monitoring and Mitigation Plan (PRMMP) should be prepared and implemented by a BLM-permitted paleontologist and approved by the BLM and Imperial County.

3.2.7 Residual Effects after Mitigation

The implementation of the above mitigation measure in addition to the 2006 Draft EIR/EIS and 2008 Final EIR/EIS mitigation measures would substantially reduce potential adverse effects on scientifically significant paleontological resources. Such mitigation measures have been proven to be effective in reducing adverse effects on fossils resulting from surface-disturbing projects on BLM land throughout the western United States. However, even in the most effective

July 2019 3.2-10 U.S. Gypsum Draft SEIS Chapter 3.2: Geology/Mineral Resources/Paleontology paleontological mitigation monitoring program, inadvertent damage to paleontological resources can occur. This damage occurs at the point at which the fossils are uncovered by excavation equipment, and in cases in which fossils are not identified by paleontological monitors during excavation. The damage caused by construction equipment can typically be repaired in a paleontological laboratory. However, damage to fossils that are not identified by paleontological monitors represents an unavoidable adverse effect.

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3.3 HYDROLOGY AND WATER QUALITY

The effects of the Proposed Action and its Alternatives on surface water, groundwater, and water quality were analyzed in Sections 3.3 and 4.2 (Hydrology and Water Quality, and Irreversible and Irretrievable Commitment of Resources) of the 2006 Draft EIR/EIS and Appendices C-1 and C-2 of the 2008 Final EIR/EIS. This section addresses new information available since publication of the 2006 Draft EIR/EIS and the 2008 Final EIR/EIS, including any new effects of the Proposed Action and its Alternatives on these resources within the affected environment, or any effects that were not analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. New alternatives are analyzed to support the USACE’s decision relating to USG’s application for a permit under Section 404 of the CWA.

3.3.1 Affected Environment

The affected environment of the Proposed Action and its Alternatives was presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. Those documents described the climate, geology, hydrology, groundwater use and quality, water use at the Plant, basin conditions, and groundwater level data. The existing conditions are briefly described below as detailed in the April 2018 Hydrologic and Water Quality Study prepared by Dudek (Appendix H) and the November 14, 2018 Update on Groundwater Conditions Memorandum prepared by Todd Groundwater (Appendix I).

3.3.1.1 Surface Water Hydrology

Quarry: The affected environment in the vicinity of the Quarry is an active open pit gypsum mine within an ephemeral desert wash tributary to Fish Creek Wash. The tributary is located in unincorporated Imperial County. The existing and proposed components of the Proposed Action that are on public lands, including a portion of the Quarry, the existing waterline replacement, and the proposed new waterline for the Quarry and the IID water supply alternatives, comprise approximately 1,100 acres.

Surface flow generated from the basin of the Quarry is part of the 22,615-acre Fish Creek Wash (HUC 181002030602) just upstream from where Split Mountain Road crosses Fish Creek Wash. Fish Creek Wash spreads out into an alluvial fan with multiple mutable channels that serve as active channels during flow events. Flow in this braided system travels northeast until it converges with San Felipe Creek (HUC 18100203) approximately 10 miles away. San Felipe Creek resembles a more defined, single-thread channel that drains to the Salton Sea (HUC 1810) approximately 20 miles east of the confluence with Fish Creek Wash. The majority of San Felipe Creek is also ephemeral, although intermittent flows (driven by groundwater discharge) begin in San Felipe Creek approximately 14 miles downstream (northeast) from the Quarry.

The drainage area being considered for this Draft Supplemental EIS encompasses approximately 7,000 acres of sparsely vegetated land. The Georgia-Pacific 40-acre parcel is also identified as being within the Proposed Action site as shown in Figure 2-3. The Georgia-Pacific parcel is included in the 2018 hydrology and hydraulic analyses conducted for the Proposed Action. The

U.S. Gypsum Draft SEIS 3.3-1 July 2019 Chapter 3.3: Hydrology and Water Quality parcel is part of the undeveloped easterly portion of the drainage area. The land use for the parcel is to remain unchanged in the proposed condition.

Jurisdictional Tributaries: Field surveys of the Quarry and Plant water pipeline areas were conducted on April 19, 2016 through April 21, 2016 to delineate jurisdictional tributaries and any wetland resources associated with jurisdictional tributaries. The areas of the Proposed Action and its alternatives contain unnamed tributaries (non-wetlands waters) that ultimately flow into the Salton Sea. The tributaries are all characterized as ephemeral with little or no vegetation. A total of 325.79 acres of unnamed tributaries occur in the Quarry area. No wetland habitat was identified to occur in the Quarry area.

A total of 0.21 acre of unnamed tributaries and no wetland habitat were identified in the alignment for the proposed waterline/powerline extending from the Quarry to Well No. 3. A total of 1.55 acres of unnamed tributaries and no wetland habitat were identified in the Plant waterline replacement alignment. The November 2016 Jurisdictional Delineation (JD) Report was field- verified with representatives from the USACE in April 2018. The 2016 JD Report is included as Appendix J.

In October 2010, an aquatic resources survey was conducted for the County of Imperial in the location of the proposed water line from the Westside Main Canal to the Plant, approximately 85 feet south of the centerline of the Union Pacific Railroad tracks (Alternatives 3 and 4). Two drainage systems were identified within the survey area: a portion of the Yuha Desert drainage system (HUC 181002040806), and the Westside Main Canal (fed by Colorado River Water). The two systems are separated from each other by the Westside Main Canal berm or levee. The survey area includes 2.25 acres of the Westside Main Canal. The canal is identified as waters of the United States. The 2010 JD Report is included as Appendix K.

3.3.1.2 Groundwater Hydrology

The Proposed Action and its alternatives overlie the Coyote Wells Valley Groundwater Basin (Number 7-29) and the Ocotillo Wells subbasin of the Borrego Valley Basin (Number 7-24) as defined by the California Department of Water Resources (DWR).

Borrego Springs Groundwater Basin The DWR divided the Borrego Valley Groundwater Basin (7-24) in 2016 into two subbasins: Borrego Springs Subbasin (7-24.01) and Ocotillo Wells Subbasin (7-24.02). DWR has designated the Borrego Springs Subbasin of the Borrego Valley Basin as being in critical overdraft. Ocotillo Wells Subbasin, however, is not rated as being in overdraft or as a being high- or medium-priority basin for remedial management to achieve groundwater sustainability.

The Ocotillo Wells Subbasin underlies Lower Borrego Valley in eastern San Diego County and western Imperial County. As described in DWR Bulletin 118, the subbasin is bound on the northeast and the east by the Coyote Creek fault and the Superstition Mountain fault. A surface drainage divide separates the Ocotillo Wells Subbasin from the adjoining Coyote Wells Valley groundwater basin to the south. The Fish Creek Mountains and Vallecito Mountains bound the west side of the subbasin. The subbasin is separated from the Borrego Springs subbasin to the

July 2019 3.3-2 U.S. Gypsum Draft SEIS Chapter 3.3: Hydrology and Water Quality northwest by San Felipe Creek and is crossed by tributary washes to San Felipe Creek, including Fish Creek Wash and Carrizo Wash.

The active USG Quarry Well (Quarry Well #2) and the proposed Quarry Well #3 are located in the Ocotillo Wells Subbasin. The subbasin aquifer is separated into an upper and lower aquifer by an aquitard estimated to be 100-200 feet thick. Most well pumping is expected to occur in the lower aquifer.

Coyote Wells Valley Basin The USG Plant and its groundwater production wells are located in Coyote Wells Valley Groundwater Basin. Coyote Wells Valley Basin encompasses 145,635 acres (227 square miles) in the Yuha Desert west of Imperial Valley, California. It is located mostly in Imperial County, with the western edge extending into San Diego County. The Basin is bounded by the Coyote Mountains to the north and the Jacumba Mountains to the west and southwest. These boundaries correspond generally to geologic contacts between alluvium and less permeable geologic formations as mapped by DWR. The southern basin boundary is arbitrarily set at the United States-Mexico border. The ill-defined eastern boundary is a roughly north-south line from Superstition Mountain in the north to the international border, and separates Coyote Wells Valley Basin from the Imperial Valley Groundwater Basin (Number 7-30). The major surface water drainage is Coyote Wash. Part of the northeastern boundary is a surface drainage divide connecting the Coyote Mountains with Superstition Mountain. USG has three production wells in Coyote Wells Valley Basin (USG-4, USG-5, and USG-6). DWR has not designated this basin as being in critical overdraft or as a high- or medium-priority basin for achieving groundwater sustainability.

Ocotillo-Clark Valley Groundwater Basin This groundwater basin (Number 7-25) lies immediately adjacent northeast of Ocotillo Wells Subbasin. This basin is characterized by general groundwater flow toward Clark Dry Lake on the north end and the Salton Sea for the remainder of the basin. The groundwater basin historically has been developed for agricultural and domestic water supplies. Most agriculture near the Salton Sea is irrigated with imported water from the Imperial Irrigation District. Some farms have been supplied (at least historically) by groundwater. The Ocotillo-Clark Valley Basin includes the lower reaches of Fish Creek Wash, Carrizo Wash, and San Felipe Creek, and San Sebastian Marsh, which is designated critical habitat for desert aquatic species listed under the Endangered Species Act.

3.3.2 Methodology

The hydrology and water quality effects of the Proposed Action were analyzed in Section 3.3 of the 2006 Draft EIR/EIS. Clarifications provided in the 2008 Final EIR/EIS (Appendices C-1 and C-2) were related to public comments received concerning groundwater use and quality in the Ocotillo area, and impacts on habitat associated with Fish Creek Wash. Comments and clarifications related to Fish Creek Wash impacts from quarrying were specific to Desert Pupfish (Cyprinodon macularius) habitat, and were addressed in the Biological Resources Section (2006 Draft EIR/EIS Section 4.3). This Draft Supplemental EIS describes any changes that have occurred since 2006 that are associated with the federal actions under consideration.

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This Draft Supplemental EIS analyzes whether the effects on surface water or groundwater that were described in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS have changed. The methodology for analyzing effects on surface water is presented in 3.3.2.1. The methodology for analyzing effects on groundwater is presented in 3.3.2.2, and is based on the November 14, 2018 Todd Groundwater memorandum (Appendix I).

3.3.2.1 Surface Water Hydrology

The methodology considers the prior methodology implemented for the Proposed Action and discussed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. A Hydrologic and Water Quality Study was prepared by Dudek in April 2018 to evaluate effects to surface waters and is included in this Draft Supplemental EIS as Appendix H.

Analysis for this Supplemental EIS is limited to the surface water hydrological effects related to changes in the Proposed Action that have occurred since the 2008 Final EIR/EIS. These changes include the transfer of title from public ownership to USG of 304.57 acres of the Quarry through mineral patent, the location and addition of five unpatented mill site claims to the Quarry property, the addition of a 40-acre parcel identified as the Georgia Pacific parcel, findings of the 2016 delineation of jurisdictional tributaries (field verified in April 2018) within the Quarry boundary as well as those associated with the water pipeline replacement from Ocotillo to the Plant, and findings of the 2011 JD of the IID Water Supply Alternatives.

The development of the Quarry watershed’s hydrologic parameters for the Dudek 2018 study was based on the most recent topographic data available. The existing channels identified in the topographic dataset used are treated in the model as static, concentrated flows. Based on the nature of compound drainage systems in arid regions, dominant flow paths often shift after moderate- and high-intensity runoff events. The Dudek 2018 study provides an assessment of how the additional Quarry phases and berm(s) might impact the watershed’s current hydrology based on the most recent topographic dataset. However, future drainage patterns may naturally shift within and upstream of the Quarry. The adopted Mine Plan of Operations includes Best Management Practices that USG undertakes to minimize losses of waters of the United States.

The geographic extent of the hydrologic and hydraulic modeling was confined to the Quarry watershed boundary (see Exhibit 1 of Appendix H). The assessment of the proposed Quarry water supply line, as well as impacts from the Proposed Action to downstream hydrologic regimes (Fish Creek Wash and San Felipe Creek), were based on existing studies and the historical documentation of compound channel and alluvial fan hydrologic functions in the arid southwest (see Appendix H).

A watershed hydrologic analysis was prepared for the 2-year, 5-year, 10-year, 25-year, and 100-year storm return intervals for the Proposed Action. Separate hydrologic analyses of the project Alternatives were not conducted as the Alternatives only propose modified phase boundaries within the Proposed Action footprint and do not change the hydrologic characteristics of the Quarry watershed.

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The peak flowrate corresponding to each of these storm intervals was determined utilizing the Riverside County Flood Control Hydrology Manual (although the Proposed Action site is located in Imperial County, California. Imperial County Agricultural Experiment Station (AES) does not have a published hydrology manual and provides methodology for assessing the hydrology of similar arid mountainous terrain. A similar manual and methodology has not been created for Imperial County. A single-area, unit hydrograph model was prepared to facilitate the analysis of the watershed using the Riverside County 2011 AES program. All analyses were performed using National Oceanic and Atmospheric Administration (NOAA) Atlas 14 Precipitation Data for a 6-hour storm duration. The land use is unchanged between the existing and proposed condition, and no impervious area is proposed to be added or removed.

Hydraulics

Hydraulic analysis for the existing and proposed conditions was performed using Hydrologic Engineering Center-River Analysis System (HEC-RAS) version 5.0.3 software based on the peak storm runoff flow rates.

The Ordinary High Water Mark (OHWM) was identified primarily from field evidence such as changes in sediment, vegetation, and break in slope, and is shown in Appendix H, Figure 4-1. The map of jurisdictional waters by Hernandez Environmental Services in 2016 shows all jurisdictional waters within the Proposed Action boundaries (which includes the boundaries of all proposed Alternatives).

The first goal of the hydraulic analysis was to determine and map the floodplain boundary corresponding to the 2-year, 5-year, and 10-year storm return intervals for the existing and proposed site conditions for use in delineating jurisdictional waters. Existing and proposed flow paths were determined based on topographic data. The proposed berm was modeled in HEC- RAS as a levee, which directs the program to assume that the berm will not fail or be overtopped. This method provides an analysis of the potential surface water elevation at the different stations along the berm and is used to identify points where the berm may overtop. The flood stage estimated by the 10-year HEC-RAS model was compared to the OHWM determined by Hernandez Environmental Services (2016).

The second goal of the hydraulic analysis was to provide basis for the proposed berm design. Design storms corresponding to the 25-year and 100-year storms were modeled in HEC-RAS to evaluate critical design parameters for the berm. The results of the 25-year and 100-year hydraulic analyses for the existing and proposed condition are provided in Appendix H.

Scour

Scour calculations were performed for the west side of the proposed berm, based on a 100-year storm event. Scour calculations look at the expected scour that could occur along the main flow path for the proposed condition. A map was prepared to show the reach, the location of the model cross sections, the limits of flooding, and the predicted scour (Scour and Floodplain Work Map, Appendix H, Exhibit 7). The components of scour used to determine the total maximum expected scour for a 100-year storm event are low flow incisement, bed form scour, and general

U.S. Gypsum Draft SEIS 3.3-5 July 2019 Chapter 3.3: Hydrology and Water Quality scour. The total scour for a given cross section was taken as the sum of these three scour components. A safety factor of 1.3 was applied to the total scour calculated to arrive at the total predicted scour.

Sediment Deposition

An evaluation of expected total sediment deposition was performed at the request of the USACE. The sediment deposition calculations were conducted using methods described in the United States Department of Agriculture Natural Resource Conservation Service’s (NRCS) National Engineering Handbook. Total sediment deposition is the amount of sediment that can be expected to reach the base of the watershed and is based on total soil loss and a sediment delivery ratio for the given watershed.

Total soil loss is estimated using the NRCS’s Revised Universal Soil Loss Equation (RUSLE), which considers rainfall, erodibility, topography, ground cover, and support practice. The rainfall factor used in the RUSLE is selected using an average annual rainfall erosion index for a given area based on 22 years of storm data compiled by the NRCS. The erodibility factor is selected using the NRCS Soil-Erodibility Nomograph for a given soil type. The topographic factor is estimated using the NRCS Slope-Effect Chart that estimates a topographic factor using a combination of the slope and length of slope. The cover factor is selected based on land use and the type of plant cover in the area. The support practice factor is selected based on the different control practices implemented that reduce erosion potential and drainage patterns. If erosion control practices are not implemented on the site, the support practice factor is omitted. Sediment delivery ratio is estimated based on the size of the drainage area.

The total sediment deposition for the proposed westerly drainage area was estimated by multiplying the total soil loss calculated by the sediment delivery ratio. The sediment delivery ratio is a measure of the fraction of soil eroded and maintained in suspension compared to that which will settle out along the flow path.

Aquatic Resources Delineation

Following a review of aerial imagery and mapping, survey transects were selected for field verification of stream presence indicators. The JD survey area included all of the USG holdings at the Quarry, a 150-foot wide alignment north of the Quarry tram railroad for the proposed waterline/powerline from the Quarry to Well No. 3, and the alignment between the existing Evan Hewes Highway and old Evan Hewes Highway where replacement of the waterline from Ocotillo to the Plant is proposed.

Field surveys were conducted April 19 through 21, 2016, following guidelines established in the 2014 Mapping Episodic Stream Activity (MESA) Field Guide. Surveyors walked the selected transects a minimum of 100 feet upstream and downstream (wherever a transect crossed a drainage, the area crossed was examined up to 100 feet upstream and downstream), noting the presence or absence of fluvial activity, boundaries of geomorphic units, changes in plant species composition between different geomorphic units, photographing points of transition, and mapping the watercourse and watercourse boundaries. The locations of areas measured were

July 2019 3.3-6 U.S. Gypsum Draft SEIS Chapter 3.3: Hydrology and Water Quality recorded using a hand-held GPS. The presence of an OHWM was recorded and, where an OHWM was evident, the width of the OHWM was measured and recorded. The OHWM was determined based upon erosion, the deposition of vegetation or debris, and changes in vegetation, as described in A Field Guide to the Identification of the Ordinary High Water Mark (OHWM) in the Arid West Region of the Western United States (August 2008). Where changes in plant community composition were apparent, the area was examined for the presence of wetlands following guidelines established in the U.S. Corps of Engineers Wetlands Delineation Manual (Y-87-1) (1987).

3.3.2.2 Groundwater Hydrology

Since the 2008 Final EIR/EIS was published, USG, in partnership with the U.S. Geological Survey (USGS), has been systematically monitoring the Coyote Wells Valley Groundwater Basin; USG and their consultants have been preparing annual groundwater reports since 2012. These Annual Reports update the current monitoring network, assess water level and water quality data, and assess whether changes in groundwater conditions exceed the early warning thresholds. These thresholds were derived from the 2008 EIR and have since been updated through discussions with USG, the County, and the Sierra Club. The 2018 Annual Report (on file with Imperial County) provides an up-to-date summary of monitoring results and thresholds.

Table 1 of Appendix I identifies all actively monitored wells within and just east of the Coyote Wells Valley Groundwater Basin. In 2018, the USGS monitored water levels in 27 wells and water quality in 18 wells. USG monitors both water levels and water quality in five additional wells. The USGS provides water level and water quality data on a semi-annual basis. (Note: USG monitors water quality in their pumping and monitoring wells using field methods including transducers and conductivity meters. While USG follows proper protocols for this field analysis, it is not the same as the USGS monitoring program which analyzes the water quality samples using laboratory methods. Water level monitoring is consistent with USGS protocols). Water level and water quality data are uploaded semi-annually after being collected, to the USGS portal and are included in the subsequent year’s annual report. USG has probes in five wells monitoring both water levels and water quality. USG data collection includes data loggers in USG-4, USG- 5, and USG-6 that measure water levels in these wells daily.

Water Levels: Figure 3 of Appendix I shows the location of key wells and hydrographs of groundwater levels. Key wells were selected on the basis of relatively complete water level histories and representative locations that show trends within the groundwater basin. Monitoring wells 31B1 and 36D2, located near the USG production wells, show similar trends (decrease from 1990s to 2008, slight increase from 2008 to 2015 and a slight decrease from 2015 to 2018). This pattern mirrors the pumping at the USG plant, with decreased water levels in times of greater pumping and relative recovery during lower pumping. These short-term changes are not visible in wells located farther from the plant, for example, wells 24D1 or 16J1. These wells continue a steady trend (decreasing and increasing respectively) although USG pumping was reduced to half from 2009 to 2015. Wells along the eastern edge of the basin, 42L1 and to a lesser extent 32R1, reflect a seasonal variation, showing sharp increases shortly after peak precipitation events (1993 and 1997).

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The reporting period for the USG water level and water quality monitoring program is Spring to Spring measurements with publication of the data annually in October. Of the 27 wells monitored, nine recently showed increasing water levels, five showed stable water levels, and 13 showed decreasing water levels. USG-5 showed the largest increase in water level (5.9 ft in Spring 2018) and during the same period, USG-4 showed a 3.5-foot decrease; however, these wells do not reflect long-term trends but represent the variable pumping rate by USG.

There are only a few wells in Ocotillo Wells Subbasin. The USGS National Water Information System (NWIS) and DWR Water Data Library indicate only two wells in the subbasin with water level data. Well (12S/8E-22E1) located approximately 7 miles north-northwest of the Quarry Well, provides groundwater depth data for some time periods since 1951. Groundwater levels at this well in 2017 indicate that the depth to groundwater is 112.9 feet. Past groundwater levels at the well have ranged from 102 to 117 feet below ground surface. Well 12S/9E-23D1, located about 7.5 miles northeast of the Quarry Well, shows groundwater depths greater than 150 feet from 1980 to 2014. The USG Quarry Well #2, located on the western margin of the subbasin, has a depth to groundwater of 307.5 feet.

Water Quality: The 2006 Draft and 2008 Final EIR/EIS indicated that the primary causes of potential groundwater quality degradation from increased groundwater production would include:

 lateral migration of saline water from Tertiary marine sediments that crop out in the Ocotillo and No Mirage area (an unincorporated planning area of the County) and areas to the east of Coyote Wells, or  vertical migration of saline water from the Tertiary marine sediments present at depth below the alluvial aquifer.

The monitoring program is designed to detect changes in TDS concentrations due to increased groundwater pumping by USG. The use of TDS as an indicator for general groundwater quality is a simplified, but widely accepted, method to detect changes in general water quality. TDS monitoring of groundwater has continued since 2008 with semi-annual monitoring over the basin.

Figures 4a and 4b of Appendix I show TDS concentrations by well for each spring monitoring event. Figure 4a shows TDS concentrations in all wells using a scale of 0 to 1,600 mg/L and Figure 4b shows TDS data from all but two wells with a more focused scale from 0 to 600 mg/L. Most wells show relatively stable TDS concentrations over time. Wells 24B1 and 30R1 showed an increase in TDS from 2012-2017 but have since shown a decrease in concentration in 2018.

Groundwater quality in the Ocotillo Wells Subbasin is only available for well 12S/9E-23D1 (7.5 miles away). TDS concentrations range between 1,650 and 1,740 milligrams per liter (mg/L).

For the Coyote Wells Valley Basin, the Todd Groundwater memorandum (Appendix I) focused on groundwater conditions in the Coyote Wells Valley Basin, where USG has developed and maintained a monitoring program and implemented performance standards that serve as an early

July 2019 3.3-8 U.S. Gypsum Draft SEIS Chapter 3.3: Hydrology and Water Quality warning to changes in the Coyote Wells Valley Basin. Water levels and water quality data are compiled, analyzed, and reported annually. Only limited changes have occurred in the basin from groundwater users. Changes in the basin since 2008 do not change the findings in the 2008 Final EIR/EIS. It is also noted that Coyote Wash and Palm Canyon Wash drain toward Imperial Valley, not San Felipe Creek.

The existing Well #2 and the proposed Well #3 are in the Ocotillo Wells Subbasin, adjacent to and upstream of San Felipe Creek. Pumping from Quarry Well #2 is unlikely to have caused the changes in San Felipe Creek because of its small withdrawal rate, pumping from the deep aquifer, distance from San Sebastian Marsh, and existence of intervening fault barriers. Other pumping in the basin is ongoing and minor. In conclusion, any changes in the basin since 2008 do not change the findings in the 2008 Final EIR/EIS.

San Sebastian Marsh is in Ocotillo-Clark Valley Basin and thus, was considered in the Todd Groundwater memorandum (Appendix I). While emphasizing that a systematic impacts analysis was not conducted, Todd Groundwater notes that groundwater pumping has changed recently in proximity to San Sebastian Marsh as conversion of historical agricultural lands to a solar farm has reduced groundwater pumping.

3.3.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals

Since the 2008 Final EIR/EIS, the State of California has enacted and implements the Sustainable Groundwater Management Act of 2014 (SGMA). The SGMA applies to 127 groundwater basins defined by DWR and designated as medium- and high-priority. SGMA does not apply to the remaining groundwater basins (designated as very low- and low-priority); nonetheless, local agencies may choose to apply the SGMA framework to these basins as well.

In September 2015, the Imperial County Board of Supervisors provided notice to DWR that Imperial County had resolved to assume the role of a Groundwater Sustainability Agency (GSA) for all groundwater basins underlying the County. In its resolution to become a GSA (Imperial County Board of Supervisors Resolution No. 2015-122), the County expressed its commitment to sustainable groundwater use and cited its jurisdiction over groundwater basins county-wide. The County also cited its long experience and background in groundwater management and monitoring, including the County Groundwater Management Ordinance.

The Borrego Valley GSA, composed of the County of San Diego and the Borrego Water District through a Memorandum of Understanding dated October, 2016 is the exclusive GSA for the San Diego County portion of the Ocotillo Wells Subbasin and the neighboring Borrego Springs Subbasin (7-24.01).

The Borrego Springs Subbasin has been designated by California Department of Water Resources as critically overdrafted high-priority groundwater basin. Both the Coyote Wells Valley Groundwater Basin (No. 7-29), which contains the USG Plaster City facility, and the Ocotillo Wells subbasin of Borrego Valley (7-024.02) which contains the USG Quarry, are designated by DWR as very low-priority basins. Ocotillo-Clark Valley is designated as a low- priority basin.

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3.3.4 Direct and Indirect Effects

3.3.4.1 Alternative 1: Proposed Action

Section 3.3.5.2 of the 2006 Draft EIR/EIS identified the potential effects that could result from the proposed mining operations within the eastern half of the Quarry watershed, and the modification of stormwater conveyance from the western half of the Quarry watershed. These effects included reducing water levels in other areas of the basin because of increased pumping for the Quarry operations, degrading water quality if increased pumping resulted in the vertical migration of saline water from the shallow aquifer, and negatively affecting or disrupting the existing flows of surface water from the Quarry to the downstream Fish Creek Wash alluvial fan. Potential effects to ephemeral streams along the proposed Quarry water supply line, and to the hydrologic regimes of the downstream water bodies, were identified as short-term.

This Supplemental Draft EIS discusses the effects of the Proposed Action due to new or changed information since the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

Redirection of Surface Flow: Runoff in the existing, unnamed ephemeral creek bed would be decreased by the proposed Quarry operations. The proposed site grading would capture runoff from the easterly portion of the watershed and convey it into a new drainage system. For this reason, the watershed was analyzed as two separate drainage areas corresponding to two separate drainage paths. Hydrology maps are included in Appendix H for the existing and proposed conditions.

Tables 3.3-1 and 3.3-2 show the expected peak flows from the unit hydrograph analyses for the existing and proposed conditions. All input and results from the hydrology model are provided in Appendix H.

Table 3.3-1 Existing Condition Unit Hydrograph Peak Flowrate 2-YR (cfs) 5-YR (cfs) 10-YR (cfs) 25-YR (cfs) 100-YR (cfs) 750 1,500 2,200 3,500 5,800

Table 3.3-2 Proposed Condition Unit Hydrograph Peak Flowrate Watershed 2-YR (cfs) 5-YR (cfs) 10-YR (cfs) 25-YR (cfs) 100-YR (cfs) Westerly 450 900 1,300 2,000 3,300 Easterly 350 700 1,011 1,600 2,600

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Although the conveyance of potential flow through the Quarry was not modeled, it is reasonable to assume that most, if not all, runoff generated within the easterly section of the Quarry watershed will be captured and retained within the proposed excavated pits. Any flows exceeding excavation pit storage would be conveyed downstream into the Fish Creek alluvial fan system with a decreased total volume and potentially reduced peak flow rate. Based on the proposed topography within the Quarry, stormwater captured in the extraction pits would eventually percolate into the local aquifer and/or evaporate.

Flows generated within the western half of the Quarry watershed would also be affected. Analysis of the HEC-RAS model results (Appendix H) were used to identify locations along the berm that would potentially overtop, allowing surface flow into the Quarry. The HEC-RAS 100-year event model indicated five stations where the berm would not provide the required 2-feet of freeboard, as documented in Appendix H. Further, the model could not rule out the potential for runoff from a 100-year event to overtop the berm in additional locations. Model stations spaced 500 feet apart may not have captured sections of the berm where water would exceed the proposed 5-foot berm height. For example, the berm intersects the main channel where the channel banks are taller than 8 feet (adjacent Phase 2); at this location the berm would act as a check dam, impounding all flow and overtopping directly into the Quarry extraction pits. Overtopping of the proposed berm could further reduce surface flows and sediment loading to Fish Creek Wash downstream.

A total of 327.55 acres of jurisdictional tributaries were identified within the entire area of the Proposed Action and its alternatives (Sutfin et al. 2014). Surface flows generated within the Quarry watershed discharge to the apex of the Fish Creek alluvial fan, where the water then flows through an approximate10-mile network of braided ephemeral channels before discharging to San Felipe Creek. The alluvial fan functions like a sponge capturing runoff and sediment. The majority of the water retained within the channels is lost to the high evapotranspiration demands of this arid region (Levick et. al., 2008). A small percentage of the water is held in soil tension storage, and excess water above soil tension storage capacity percolates to groundwater. The potential reduction of runoff and sediment loads from the Quarry watershed for any event significant enough to generate flow would have a minimal impact on these existing hydrologic processes within the Fish Creek alluvial fan.

Further downstream San Felipe Creek contains habitat for the Desert pupfish (C. macularius). This habitat is fed by groundwater discharge (like a spring) and is not dependent on surface flow generated from the Quarry watershed. Reduced surface flow to the Fish Creek Wash alluvial fan would not adversely impact groundwater discharge to San Felipe Creek. The potential for the Proposed Action to affect Desert pupfish habitat is discussed in greater detail in Chapter 3.4 of this document.

Water Quality: The potential for the Proposed Action to result in adverse effects to downstream surface water or groundwater quality is considered minimal due to the following:

 Most, if not all, of the water will be retained within the pits as a result of the proposed excavation pits. As a result, this reduced the total volume of water discharged from the Quarry watershed.

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 The Proposed actions are not anticipated to adversely impact the water quality in the Salton Sea or Imperial Valley Drains, which are listed as impaired for nutrients, pesticides, herbicides, arsenic and selenium. While arsenic is present at two parts per million (ppm) in the black anhydrite which occurs at the bottom of the gypsum seam, the potential exposure of this material during mining operations will not result in a significant release of arsenic to downstream waters as this material is not mined and typically left in place. Furthermore, the natural concentrations of arsenic in surrounding soils in Imperial County are likely greater than 2 ppm (Bradford et. al., 1996) and serve as the primary source of arsenic to the Salton Sea. A reduction in discharge from the Quarry watershed will likely result in a reduction of natural arsenic transported to downstream waters.  Groundwater elevations from the nearest well (~7 miles north-northwest of the Proposed Action area) are approximately 400 feet below the lowest point in the Proposed Action area. Impacts on groundwater quality from increased localized infiltration during the infrequent but intense storm events are considered negligible.

 The potential effect to downstream water quality conditions related to the dust generated from mining activities would not be considered adverse due to BMPs for dust control and County of Imperial fugitive dust rules. Any potentially adverse effects would be reduced by the incorporation of recommendations identified in the 2008 Final EIR/EIS.

3.3.4.2 Alternative 2: No Action Alternative

The No Action Alternative is described in detail in Chapter 2. None of the activities associated with the Proposed Action or its alternatives would occur. The Quarry and Plant would continue to operate as presently permitted and regulated. The potential effects to surface hydrology as analyzed and described in Section 3.3 of the 2006 Draft EIR/EIS and 2008 Final EIR/EIS are unchanged.

3.3.4.3 Alternative 3: Partial IID Water Supply Alternative

Alternative 3, described in detail in Chapter 2, is the Proposed Action except that the processing water would be partially replaced with irrigation water from the IID Westside Main Canal and new settling ponds for treating the IID water would be constructed on USG-owned lands at the Plant. This alternative was analyzed and presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. The details of the alternative and its effect on hydrology and water quality are the same as were disclosed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

Construction of the proposed new pipeline between the Westside Main Canal and the Plant would result in 16 acres of temporary and permanent impacts on drainages located within the affected area, as described in the 2010 JD. Approximately 9.12 acres along the pipeline alignment would be temporarily impacted during the construction period. Permanent impacts to waters of the United States were determined to be minimal (0.001 acres) and would be confined to the Westside Main Canal where the intake pump would be constructed.

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The Project Proponent would be required to obtain authorizations from the CDFW and the Colorado Basin RWQCB for permanent impacts on State jurisdictional waters along the pipeline alignment, and from the USACE for discharges into federal jurisdictional waters.

3.3.4.4 Alternative 4: Full IID Water Supply Alternative

Alternative 4, described in detail in Chapter 2, is the same as Alternative 3 except that all the water for Plant operations would come from the IID Westside Main Canal and the existing waterline to the Plant would be removed. This alternative was analyzed and presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. The alternative has not changed, and its effect on hydrology and water quality is the same as was disclosed in the earlier documents.

The temporary impacts and permanent losses of this alternative on the hydrologic resources would be the same as for Alternative 3, and the proponent would be required to obtain the same permits.

3.3.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative

Alternative 5, described in detail in Chapter 2 and shown in Figure 2-6, is the Proposed Action but with Phase 10 reduced, Phase 10P eliminated, and the berm modified correspondingly. In addition, the proposed berm between Phases 6 in 9 in the upper (southern) part of the Quarry watershed would be eliminated; a natural topographic break will serve as the storm water barrier instead. This modified berm alignment allows for an additional 120-acres to discharge into the Quarry, but at less than 2% of the total watershed area it is considered minimal and would not represent a change in the modeled hydrologic analysis of the easterly and westerly peak flowrates identified in Table 3.3-2.

The impacts on hydrologic resources associated with this alternative are similar in nature to the Proposed Action, although they differ in their extent. The total losses of waters of the United States would be reduced from 133.63 acres to 117.62 acres for the mining area and berm alone. Eliminating Phase 10P would eliminate direct impacts on the wash along the boundary of that phase, and would avoid indirect downstream impacts from Phase 10P on Fish Creek.

3.3.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative

Alternative 6, described in Chapter 2 and shown in Figure 2-7, is the Proposed Action except that Phases 4 and 5 would be reconfigured to reduce the loss of waters of the United States, and the berm would be modified correspondingly.

The nature of the impacts on hydrologic resources associated with Alternative 6 are the same as the Proposed Action. The total loss of waters of the United States would be reduced from 133.63 acres under the Proposed Action to 125.43 acres for the mining area and berm alone.

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3.3.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative

The impacts on hydrologic resources associated with Alternative 7 are similar in nature to the Proposed Action. The direct loss of waters of the United States would be reduced from 133.63 acres under the Proposed Action to 126.78 acres for the mining area and berm alone. However, indirect impacts would increase under this alternative as mining would continue in the channel immediately upstream and downstream Phases 2P, 3P(North) and 3P(South).

3.3.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint

Alternative 8, described in detail in Chapter 2 and shown in Figure 2-9, represents the Proposed Action but with changes to the mining boundaries of Phases 7 and 8. The proposed stormwater berm would be as described for Alternative 5 and will include a berm along all of Phases 10 and 10P, and extend to the northern limit of Phase 10P.

The impacts of this alternative on hydrologic resources in the project area would be qualitatively the same as those of the Proposed Action. Losses of waters of the United States in the upper Quarry watershed would be reduced from 133.63 acres under the Proposed Action to 122.35 acres for the mining area and berm alone. The overall mining footprint would be reduced by 11.28 acres, thereby decreasing potential mining beneath the valley alluvium where gypsum ore has been determined to be most abundant.

3.3.5 Cumulative Effects

3.3.5.1 Geographic Scope of the Cumulative Effects Analysis

The geographic area used for evaluating the cumulative effects of this project on surface water resources is the affected Fish Creek Wash (HUC 181002030602) and San Felipe Creek (HUC 18100203) watersheds. The geographic area is included within the area mapped in Appendix F.

3.3.5.2 Timeframe of the Cumulative Effects Analysis

The timeframe of the cumulative effects analysis is considered to be the life of the Proposed Action or its alternatives, estimated at 73 years of Quarry operations, an additional 7 years of Plant operations, and an additional estimated 10 years for facilities decommissioning and final reclamation/revegetation.

3.3.5.3 Past, Present, and Reasonably Foreseeable Actions

The Proposed Action and its alternatives would result in adverse direct or indirect effects on hydrology and water quality. These include: (1) temporary impacts on a number of ephemeral streambeds along the course of the proposed waterline/powerline from the Quarry to the

July 2019 3.3-14 U.S. Gypsum Draft SEIS Chapter 3.3: Hydrology and Water Quality proposed Well No. 3, limited to effects during construction activities because the existing drainage patterns along the alignment would be preserved; and (2) potential reduction of surface flows and sediment loading to the Fish Creek Wash alluvial fan and San Felipe Creek.

The cumulative effects analysis was limited to a review of projects that would also result in adverse effects to the watersheds of Fish Creek and/or San Felipe Creek, of which there were none identified. Therefore, the Proposed Action and its alternatives would not result in cumulative impacts.

3.3.6 Mitigation Measures

Mitigation measures were proposed in the 2006 Draft EIR/EIS to address potential impacts on hydrology and water quality. No changes to the mitigation measures (3.3-1, 3.3-2 and 3.3-7) as listed in Appendix E are proposed. Mitigation of losses of waters of the United States would include the implementation of mitigation required in permits obtained for this project, including permits required under Sections 401 and 404 of the Clean Water Act and the Section 1602 Lakes and Streams Alteration Agreement required by the State of California. Mitigation of the pipeline impacts of Alternatives 3 and 4 would be required prior to issuance of construction permits. The issuance of a CWA 404 permit demonstrates that impacts have been mitigated through the avoidance, minimization and compensation of loss of waters of the United States. If the loss of waters is unavoidable, compensatory mitigation may be required. USACE regulations regarding compensatory mitigation are located at 33 CFR 332. If compensatory mitigation for loss of waters of the United States is required, an evaluation of proposed compensation must be in compliance with these regulations.

3.3.7 Residual Effects after Mitigation

With implementation of the proposed mitigation measures, impacts on surface and groundwater resources including water quality would be avoided or substantially reduced. As a result, the proposed project would result in no adverse unavoidable impacts.

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3.4. VEGETATION AND WILDLIFE

The effects of the Proposed Action and its alternatives on vegetation and wildlife resources were analyzed in Sections 3.4 (Wildlife), 3.5 (Vegetation), and Appendices C-1 through C-5 of the 2006 Draft EIR/EIS. This section addresses new information available since publication of that draft and the 2008 Final EIR/EIS, any new effects of the Proposed Action and its alternatives may have on these resources within the affected environment, and any effects that were not analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

3.4.1 Affected Environment

This section of the Draft Supplemental EIS summarizes and incorporates the Biological Resources Technical Report (BRTR) prepared by Aspen Environmental Group, March 2019 and included as Appendix L. Below is a description of the affected environment (as surveyed in November 2017) associated with the project.

Quarry. The Quarry is located in an elongated valley along an unnamed wash and on the lower hillsides of the northeastern Fish Creek Mountains. The dominant landforms are a broad alluvial wash and adjacent toe slopes and mountainsides. The Quarry expansion area is on middle and lower slopes and the adjacent part of the alluvial wash. Undisturbed upland slopes are composed of two parent materials: gypsum outcrops and metamorphosed sedimentary rock overlying older granitic rock. Both rock types support very sparse desert shrublands dominated by creosote bush (Larrea tridentata) on the igneous material and by pygmy cedar (Peucephyllum schottii) on the gypsum. The mountainsides slope at a gradient of about 20 percent and are rocky, with frequent areas of exposed bedrock and actively eroding talus. Exposed ridgetops have thin soil overlying bedrock.

The alluvial wash slopes at a gradient of about 2 percent generally toward the northwest. The slopes of the Fish Creek Mountains to the northeast and Split Mountain to the southwest drain into this wash, via unnamed washes and small washlets, and by sheet flow. Surface runoff drains to the north across the alluvial fan into Fish Creek Wash, through a system of braided tributaries across the bajada to San Felipe Creek and San Sebastian Marsh, and then to the Salton Sea. The alluvial wash has a series of braided channels that evidently are scoured and redirected by infrequent flash flooding. In some areas, the channels are deeply incised to bedrock. Alluvial soils throughout the wash are poorly developed, and consist of sands with a high proportion of 3 to 10-inch cobbles, larger rocks, and boulders. Eroded channel banks show a similar high rock content in the subsurface layers. The alluvial soils support desert shrublands composed primarily of creosote bush, with stands of smoke tree (Psorothamnus spinosus) and catclaw acacia (Senegalia [Acacia] greggii) in the main channels.

Two rock types are found on the undisturbed upland slopes at the Quarry: gypsum outcrops and metamorphosed sedimentary rock overlying older granitic rock. Both rock types support very sparse desert shrublands dominated by pygmy cedar on the gypsum, and creosote bush on the metamorphic sedimentary material. Alluvial soils throughout the wash support desert shrublands composed primarily of creosote bush, with stands of smoke tree and catclaw acacia in the main

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channels. U.S. Geological Survey (USGS) topographic maps show the primary wash and several of its tributaries as ephemeral streams.

Field observations and the absence of mapped springs or perennial streams on USGS topographic maps indicate that the Quarry and the adjacent mountains lack both permanent and long-lasting seasonal water sources. There is only one identified water source within the Fish Creek Mountains, a series of natural rock tinajas1 located about 1.8 miles southeast of the Quarry area. These tinajas are known to hold water for a period of time after rain events. Other water sources are located in the Vallecito Mountains within Anza-Borrego Desert State Park, the nearest of which is over 7 miles west of the quarry site. These water sources appear to dependably supply water for wildlife for much of the year.

Characteristic wildlife species observed in the Quarry expansion area are: desert horned lizard (Phrynosoma platyrhinos), zebra-tailed lizard (Callisaurus draconoides), desert iguana (Dipsosaurus dorsalis), mourning dove (Zenaida macroura), Costa’s hummingbird (Calypte costae), verdin (Auriparus flavipes), common raven (Corvus corax), coyote (Canis latrans), black-tailed jackrabbit (Lepus californicus) and desert woodrat (Neotoma lepida). Much of the proposed Quarry area is within designated critical habitat for Peninsular bighorn sheep (PBS, Ovis canadensis nelsonii). A full list of wildlife species observed at the Quarry is included in Appendix L.

Quarry Water Pipeline and Powerline. The proposed Quarry water pipeline and powerline alignment crosses open desert shrubland on the alluvial slope and immediately adjacent toe slopes northward from the Quarry, and along the desert bajada to the proposed new well site. The powerline would be buried along most of its length and installed in an existing above-ground powerline route at its southwestern end; any new above-ground structures (poles or conductors) would replace existing structures, with no net increase (see Chapter 2, Description of the Project and Alternatives). Soils are generally a mix of rocky, coarse-textured alluvium, overlain in some areas by windblown sand. The route supports common desert wildlife species and is expected to support other species not observed during the surveys, such as those identified in the Quarry area. The area is also expected to support flat-tailed horned lizard (Phrynosoma mcallii) or Colorado desert fringe-toed lizard (Uma notata), with suitable windblown sand habitat present for the species.

Plant Water Pipeline. Approximately 5 miles of the existing pipeline alignment crosses public land managed by the BLM. This portion of the route is within the BLM’s Yuha Basin ACEC (see Section 3.6 Special Designations). The pipeline alignment crosses the desert floor within open desert shrublands and, often, barren areas along roadways. The alignment is expected to support common desert wildlife species identified in Appendix L and is expected to support other species not observed during the surveys such as those identified for the Quarry. The area is also expected to support species such as flat-tailed horned lizard and opportunistic wildlife species commonly seen in disturbed areas supporting ruderal plants, and non-vegetated areas. Examples include common ravens, which frequently perch or nest near roadways and feed opportunistically on road-killed animals. Coyotes may also take advantage of these habits.

1 A tinaja is a natural cistern-like basin that fills during rainstorms and retains water for an extended period. They are often created by erosional processes in intermittent stream channels and can serve as water sources for wildlife in otherwise dry landscapes.

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IID Water Pipeline. Under Alternative 3 or Alternative 4, a new pipeline would be constructed to carry Imperial Irrigation District (IID) water from the Westside Main Canal to the Plant. The pipeline would be approximately 5.5 miles in length, constructed within an alignment currently proposed to be either on the north side of the Union Pacific Railroad, or the north or south side of Evan Hewes Highway. The alignment for the pipeline would be a total area of impact of 30-feet wide (for trenching) and approximately 5.5 miles long. A portion of the route is within the BLM’s Yuha Basin ACEC (see Section 3.6). Most of the IID pipeline route is covered by loose sandy substrates that form stabilized sand fields and low-gradient wash habitats. Small deposits of wind-blown sand are present on the down-wind side of many of the shrubs and along the Union Pacific rail line. Near the west end of the alignment, the substrate is rockier, more stabilized, and aeolian sand deposits are not present. Near the eastern end of the alignment, the topography is very flat and the substrate is dominated by silt, forming a playa-like habitat. The margins of the canal are more mesic than other areas and provide mesquite and tamarisk (also called salt cedar) thickets that are not found elsewhere on the route. The IID pipeline route is vegetated by desert shrubs that are typical for the region. Dominant species include creosote bush, big galleta (Hilaria rigida), burro weed (Ambrosia dumosa), and honey mesquite (Prosopis glandulosa). The margins of the West Side Main Canal are vegetated with riparian herbs, grasses, and salt cedar (Tamarix sp.). There is a dense stand of honey mesquite, tamarisk, and salt bush (Atriplex sp.) just to the west of the canal. Soils include silts, sands, and small deposits of wild-blown aeolian sands on the down-wind side of many of the shrubs and along the Union Pacific rail line.

3.4.2 Methodology

The biological resources that were analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS were updated using information form current literature reviews and field surveys. Aspen Environmental Group reviewed available literature to identify special-status plants, wildlife, or plant communities known in the vicinity of the Proposed Action and the alternatives. The California Natural Diversity Database (CNDDB) was reviewed for the presence of special status species in the areas of the project components.

The analysis provided herein is based on biological field surveys conducted in October 2014, April and October 2016, and March and April 2017, by biologists with appropriate experience related to the special-status wildlife and plant species of the area (refer to Biological Resources Technical Report, Appendix L). Surveys were conducted throughout all of the proposed phases of the Quarry expansion, the proposed new Quarry pipeline alignment, and the existing Plant water supply pipeline alignment. The surveys were conducted using the complete coverage method as described in the Survey Protocols for Special Status Plants developed by BLM California State Office specifically for projects subject to BLM policy, NEPA, and the ESA. The spacing between transects was typically 10 meters, but was increased as needed where the topography made 10-meter spacing impracticable. The 10-meter spacing was intended to allow surveyors to locate small, annual, special-status plants. The locations of all special-status plants with a California Rare Plant Rank (CRPR) of 1 or 2 were recorded with a GPS unit. Surveys of the potential IID pipeline route (Alternatives 3 and 4) were conducted in 2010 and 2018 using similar methods, along “meandering” transects, ensuring that all habitat types present on the route were surveyed (see Appendix M).

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During the field surveys, all plant and wildlife species observed were recorded in field notes. Plants of uncertain identity were collected and identified later using keys, descriptions, and illustrations provided in regional references. All plant species observed during the surveys are listed in Appendix L.

3.4.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals

Since the 2006 Draft EIR/EIS and the 2008 Final EIR/EIS were prepared, there have been changes to applicable regulations, plans or policies/management goals that affect biological resource management. These changes are the revised PBS critical habitat designation and the 2016 Desert Renewable Energy Conservation Plan (DRECP) amendment to the CDCA Plan. In 2009, the USFWS published the final designation of critical habitat for PBS, replacing the original critical habitat designation published in 2001. The planned Quarry expansion area is located within designated critical habitat. The footprint of the existing Quarry (as of 2009) was excluded from critical habitat. In 2016, the BLM issued its ROD for the DRECP LUPA to the 1980 CDCA Plan. The purpose of the DRECP is to conserve and manage plant and wildlife communities in the desert regions of California, while facilitating the timely permitting of compatible renewable energy projects. The DRECP covers over 10 million acres of BLM land, including the public lands in the project area.

3.4.4 Direct and Indirect Effects

3.4.4.1 Alternative 1: Proposed Action

Vegetation and Habitat. Seven vegetation and land cover types were mapped within the area associated with the Proposed Action. Vegetation, cover types, and acreages of each vegetation and cover type within the area associated with the Proposed Action are shown in Appendix L. The effects of the Proposed Action and its mitigation were described in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS, and they have not changed. Quarry phasing and on-site reclamation as specified in the Imperial County authorization would minimize the overall effects and reduce them over time. Additional measures identified in this Supplemental EIS that would further mitigate vegetation effects include PBS critical habitat mitigation and Yuha Basin ACEC mitigation. The effects of the quarry expansion on critical habitat would be offset through PBS habitat conservation as described in Mitigation Measure 3.4-6 (Section 3.4.6). This would also conserve habitat for multiple other wildlife species. The surface disturbance effects of pipeline replacement or construction exceeding the Yuha Basin ACEC cap would be offset by removing invasive tamarisk as identified in Chapter 3.7, and as described in Mitigation Measure 3.4-14 (Section 3.4.6) and Appendix L-1.

Activities associated with the Proposed Action could lead to the spread of invasive weeds or to the introduction of new weed species in the area. Mitigation Measure 3.4-5 would require preparation

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and implementation of an Integrated Weed Management Plan to prevent or control the spread of invasive weeds. Tamarisk removal in the ACEC (Mitigation Measure 3.4-14) would increase the opportunity for native species to become established in areas cleared of invasive plants, which would improve species composition and species diversity in the ACEC. However, the use of triclopyr, imazapyr, and/or glyphosate on tamarisk could damage or kill non-target plant species, or could negatively affect insect or other animal species. The risk to non-target species would be minimized by ensuring that personnel applying these substances would be licensed and trained in the appropriate application methods of glyphosate, imazapyr, and triclopyr and adhering to California and BLM guidelines. Herbicide use for weed treatment is further analyzed in the Vegetation Treatments Using Herbicides on BLM Lands in 17 Western States Programmatic EIS (2007).

Special-status Plants. No State- or federally-listed plants were observed during the surveys or have potential to be present in the quarry expansion areas or the existing pipeline alignment (see Appendix L). One BLM Sensitive Plant, Orcutt’s woody aster (Xylorhiza orcuttii) may have moderate potential to occur due to the presence of gypsum soils, but it was not observed during protocol surveys and is not expected. No other BLM Sensitive Plants have potential to occur. Several special-status plants with a CRPR of 2B or 4 (CRPR definitions are found in Appendix L) were observed. While these species are not protected by state or federal policy, their occurrences are tracked by the CNDDB. Wiggins’ croton (Croton wigginsii) is a state-listed special-status plant that occurs primarily at the Algodones Dunes area about 50 miles east. It has been reported near the Plaster City Plant but not near the quarry. It is addressed further under Alternative 3 (Section 3.4.4.3). The quarry component of the Proposed Action may affect occurrences of Thurber’s pilostyles (Pilostyles thurberi), brown turbans (Malperia tenuis), Coulter’s lyrepod (Lyrocarpa coulteri), and annual rock-nettle (Eucnide rupestris) described in Appendix L. These species are widely distributed regionally, their conservation status does not preclude disturbing them, there is extensive undisturbed and protected habitat in the local mountains (including wilderness areas and State Park lands), and the project’s effect would to be confined to the local individuals impacted. Therefore, this effect would be relatively minor and no mitigation is necessary.

General Wildlife Effects. Most wildlife will try to avoid moving equipment, and equipment operators would avoid clearly visible wildlife (such as large mammals). However, quarrying or pipeline construction could cause injury or mortality in small mammals and reptiles, particularly during initial grading or site clearing work. Food or water could attract wildlife or feral dogs into the work area, putting wildlife at risk. Domestic dogs, if present, could prey on native wildlife, or cause injury or mortality by chasing them. Wildlife could be struck by vehicles or become trapped in trenches or materials (e.g., pipes). Nesting habitat for numerous resident and migratory birds is found throughout the area, which may be vulnerable to activities associated with the Proposed Action. Most adult birds would avoid equipment during initial vegetation clearing; however, nestlings and eggs could be destroyed during initial site clearing without implementation of measures to avoid or minimize these effects. Adult birds, nestlings, and eggs are protected by the Migratory Bird Treaty Act and by the California Fish and Game Code. Potential adverse effects can be minimized or avoided by scheduling initial site disturbance outside the nesting season. In addition, some bird species can become trapped in vertical or horizontal open pipes. Cavity-nesting species such as Say’s phoebe (Sayornis saya), owls

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(Strigiformes), woodpeckers (Picidae), American kestrel (Falco sparverius), and ash-throated flycatcher (Myiarchus cinerascens) are particularly vulnerable. Avoidance and minimization measures, such as pre-construction clearance surveys and requirement for clearly-delineated work areas are described in Section 3.4.6.

The Proposed Action could affect local wildlife movement patterns. Quarrying and construction operations would tend to dissuade most terrestrial animals from crossing the areas due to the removal of vegetation and soil that would otherwise provide food, shade, and burrowing substrate. Direct impacts, including noise, traffic, and nighttime lighting could also tend to reduce wildlife dispersal across the property. However, the undeveloped, open space surrounding the Quarry expansion areas would continue to provide travel routes around the existing and proposed Quarry operations, and the short-term nature of pipeline construction would have only a temporary and minimal effect on local wildlife movement. Because the wildlife movement could continue around the quarry expansion areas, and the pipeline impacts on wildlife movement would be short term, the overall effect on wildlife movement would be minor. They can be further reduced by implementing the avoidance and minimization measures identified in Section 3.4.6. Mitigation specific to wildlife movement is not required.

Listed Threatened or Endangered Wildlife

Peninsular bighorn sheep (Ovis canadensis nelsoni). This federally listed entity is a Distinct Population Segment (DPS) of a desert bighorn sheep subspecies (Ovis canadensis nelsoni). The PBS is federally listed as endangered, State-listed as threatened, and designated as a "fully protected animal" by the California Fish and Game Code. Nomenclature for PBS has been revised over the years, as described in Appendix L. The PBS is recognized as genetically isolated from other populations located farther to the north and east. PBS inhabit the desert slopes of the Peninsular Range from Riverside County south to Baja California, Mexico, including the Fish Creek Mountains. PBS were addressed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS, and additional data on its regional and local occurrence are provided in Appendix L.

The range of potential adverse effects of the Proposed Action on PBS includes injury, mortality, harassment, and habitat loss or degradation – including loss or degradation of designated critical habitat— as described above for common wildlife. Human presence and construction/blasting noise may disrupt PBS behavior in the quarry vicinity and may cause them to abandon areas important for foraging or lambing. PBS are most sensitive during the lambing season, and future quarry phases 6Bp, 7Bp, 8, and 9 are nearest to presumed lambing habitat. Future mining in the southern end of the planned quarry expansion areas (Phases 8 and 9) is near a narrow habitat linkage between the Fish Creek and Vallecito Mountains ewe groups. These effects can be mitigated and the “take” of PBS can be avoided by implementing avoidance and minimization measures. Mitigation identified in the 2006 Draft EIR/EIS, and additional measures developed since then, are described in Section 3.4.6. These measures include habitat reclamation and critical habitat conservation (3.4-10), PBS Monitoring and Reporting (3.4-11), and PBS Avoidance and Minimization (3.4-12). Due to its status as a State-designated Fully Protected species, avoidance measures are identified in Section 3.4.6 to fully prevent any potential for incidental take (i.e., PBS Avoidance and Minimization Measures identified in Mitigation Measure PBS-3).

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Swainson's hawk (Buteo swainsoni). Swainson's hawk is listed as Threatened by CDFW and is recognized as sensitive by the BLM. In California it nests in the San Joaquin, Owens, and western Antelope Valleys, but not in or near the area associated with the Proposed Action. The primary wintering grounds are in Argentina, and Swainson's hawks migrate through southern California every spring and fall. Suitable migratory-season foraging habitat is abundant throughout the area associated with the Proposed Action. No adverse effects are anticipated because localized seasonal foraging habitat loss would not affect Swainson’s hawk breeding populations.

Barefoot banded gecko (Coleonyx switaki). Barefoot banded gecko is listed as Threatened by CDFW and is a BLM Sensitive Species. The species occurs among crevices, rock outcrops and boulders on desert mountain slopes. The site of the Proposed Action is within the geographic range of the barefoot banded gecko. No suitable habitat is present in the areas of the proposed pipelines, nor in the proposed Quarry expansion area on the gypsum outcrops or in the alluvial wash. Marginally suitable habitat does exist on metamorphic outcrops adjacent to the gypsum outcrops. No barefoot banded geckos have been observed in the Proposed Action area during field surveys. Because only marginally suitable habitat is present in the quarry area, and there are no local records of this species, no effects to barefoot banded gecko are expected. Mitigation Measure 3.5-1e. Barefoot banded gecko was identified in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS, and consists of pre-construction surveys in the quarry expansion areas.

Desert pupfish (Cyprinodon macularius). This species is federally listed Endangered. Desert pupfish are absent from the area associated with the Proposed Action due to the absence of perennial surface water. Desert pupfish and designated critical habitat do occur lower in the watershed at San Sebastian Marsh about 7 miles northeast of proposed Quarry Well No. 3, 11 miles northeast of the Quarry, about 20 miles north of the Plant, and about 24 miles north of the proposed wells near Ocotillo. The project effects on this species were addressed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS; the potential effects of the Proposed Action on water supply to drainages connected to desert pupfish habitat are also discussed in Chapter 3.3 of this supplement. The desert pupfish critical habitat was not found to be hydrologically connected to the effects of the Proposed Action. Additionally, recent significant loss of surface water in the occupied habitat is believed to be linked to seismic activity or cessation of nearby irrigation due to conversion of agricultural lands to a solar facility. No effects to desert pupfish would result from the project.

Other Special-status Wildlife. In addition to the listed species addressed above, special-status wildlife occurring or potentially occurring on the area associated with the Proposed Action include desert kit fox (Vulpes macrotis arsipus), American badger (Taxidea taxus), loggerhead shrike (Lanius ludovicianus), burrowing owl, Colorado Desert fringe-toed lizard, and flat-tailed horned lizard (see Appendix L). The Proposed Action could directly or indirectly affect special- status wildlife through injury or mortality, harassment, or through habitat loss or degradation as described above for common wildlife. Burrowing owls, if present, are unlikely to flee the site during construction due to their characteristic behavior of taking cover in burrows. Therefore, an avoidance and mitigation strategy for burrowing owl is recommended. Pre-construction clearance surveys and clearly-delineated work areas are recommended to minimize or avoid direct impacts on special-status wildlife. In addition, habitat conservation for PBS that might be

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required for this project could also benefit multiple other species, as described in Section 3.4.6. With implementation of the recommended measures, the Proposed Action is not expected to adversely impact special-status wildlife.

3.4.4.2 Alternative 2: No Action Alternative

Effects on vegetation and wildlife from mining would be limited to the area of the existing Quarry operations. The critical habitat for PBS is identified in the undisturbed areas surrounding the existing mine, not in the existing mined areas (see Appendix L); therefore there would be no effect on critical PBS habitat.

3.4.4.3 Alternative 3: Partial IID Water Supply Alternative

Alternative 3 would not change the existing conditions or potential effects to biological resources of Quarry operations described for the Proposed Action. It would create effects associated with the new canal pipeline alignment and would potentially create effects associated with constructing the settling/evaporation ponds on the Plant site. These effects are discussed below.

Scott White and Justin Wood (then of Scott White Biological Consulting) surveyed the IID pipeline alignment options for plant species and wildlife habitat, providing data for an Addendum to the 2008 Final EIR/EIS adopted by Imperial County, on April 9, 2007. Wood (of Aspen Environmental Group) revisited the site on May 7, 2018, which was a year of low rainfall. The results of the 2018 field survey are presented below.

Vegetation and Habitat. Construction of the pipeline could affect vegetation and habitat in the IID pipeline alignment similarly as described for other locations under Alternative 1. Implementing the mitigation measures identified in Section 3.4.6 would avoid or minimize these effects. The planned location of the proposed water treatment facilities on the Plant is currently disturbed and does not support any vegetation or habitat.

Special-status Plants. The 2006-2007 rainfall year (beginning July 2006) was one of the driest on record for much of southern California, and no special status plants were found along the alignment in the 2007 surveys. However, annual plants and many herbaceous perennial plants do not grow above-ground during dry years. Because of the unusually dry conditions in the prior year, it was determined that there was a moderate or greater probability that any of the following special-status plants might occur on the proposed IID waterline route: Salton milkvetch

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(Astragalus crotalariae), Harwood’s milkvetch (Astragalus insularis var. harwoodii), sand evening-primrose (Chylismia [Camissonia] arenaria), brown turbans, hairy stickleaf (Mentzelia hirsutissima stenophylla), slender-woolly-heads (Psilocarphus chilensis), Wiggins’ cholla (Opuntia wigginsii), and Orcutt’s woody-aster (Xylorhiza orcuttii). None of these plants is listed threatened or endangered, or is a candidate or proposed for listing. Based on habitat and on geographic and elevation ranges, it was concluded that no listed threatened or endangered plants would occur within the proposed water pipeline alignment, and therefore none would be affected.

Since the 2007 field survey, an additional special-status plant, Wiggins’ croton (Croton wigginsii), has been reported locally (CBDDB 2018). It was identified in 2010 within the survey area, west of Dunaway Road, just south of West Evan Hewes Highway, and north of the Union Pacific railroad tracks. Wiggins’ croton has CRPR 2B. It is listed as BLM sensitive and State- listed as rare. It is primarily known to occur in active sand dunes at the Algodones Dunes southeast of the Salton Sea. The local occurrence is believed by CNDDB to be a human-caused introduction, probably from seed accidentally transported on recreational OHVs from the Algodones Dunes.

The overall habitat conditions on the IID pipeline route were unchanged from 2007, and Wood did not observe Wiggins’ croton at the reported location or elsewhere on the proposed pipeline route. The potential for special-status plants occurring on the route is the same as described above, with the added possibility that Wiggins’ croton could also occur. Due to the State listing status of Wiggins’ croton, an additional mitigation measure is identified specifically for this Alternative to conduct a pre-construction survey prior to finalizing the pipeline alignment and, if needed, adjust the route to avoid any persisting Wiggin’s croton occurrence.

General Wildlife Effects. Construction of the IID pipeline could cause general wildlife effects similar to those described for pipeline components of the Proposed Action. Several avoidance and minimization measures, as well as pre-construction clearance surveys and clearly-delineated work areas, are identified below in Section 3.4.6 to minimize or avoid these potential effects.

In addition, the treatment facilities associated with Alternative 3 could present a drowning hazard or health hazard to wildlife (e.g. birds, reptiles, small mammals, desert kit fox), that may attempt to reach and drink water in the treatment ponds. The treatment facilities would be fenced to minimize access by larger wildlife such as coyotes. Below-ground wire mesh would be a part of the fencing to also prevent burrowing animals such as the desert kit fox from accessing the ponds. It is proposed that the ponds will include bird diversion devises like bird netting, floating ballast balls or other systems to minimize bird attraction. With the implementation of appropriate design measures to minimize impacts on general wildlife, this alternative’s effects associated with the treatment ponds are expected to be minor.

Threatened or Endangered Wildlife

Based on a review of species occurrences in the region, habitat suitability, and elevation ranges, no listed wildlife species is likely to occur along the pipeline alignment. There is no suitable habitat for PBS, barefoot banded gecko, or other listed threatened or endangered species along

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the route. Additionally, the pipeline route is not located between occupied PBS habitat areas; therefore, pipeline construction would not introduce disturbance or barriers to PBS movement routes. No effects to listed threatened or endangered wildlife species would result from the IID pipeline alternative.

Other Special-status Wildlife. The flat-tailed horned lizard could occupy patchy windblown sand areas along the route, although it was not seen during field surveys. Other special-status wildlife, and the potential effects on them of this alternative, would be comparable to those described for the pipeline components of the Proposed Action. The mitigation measures identified in Section 3.4.6 would avoid or minimize these effects. Special-status species such as desert kit fox or flat-tailed horned lizard could be attracted to the water treatment ponds, which could present a drowning or health hazard as described under General Wildlife Effects above. Fencing and covering the treatment facilities as described above are expected to minimize these potential effects of the connected action.

3.4.4.4 Alternative 4: Full IID Water Supply Alternative

The potential effects of Alternative 4 to vegetation and wildlife resources would be identical to those described under Alternative 3.

3.4.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative

Alternative 5, described in detail in Chapter 2 and shown in Figure 2-6, is the Proposed Action but with Phase 10 reduced, Phase 10P eliminated, and the berm modified correspondingly.

Approximately 5.4 million tons less gypsum would be mined than under the Proposed Action. At a maximum permitted production of 1.92 million tons per year, this alternative would reduce the projected mine life by 2.81 years compared with the Proposed Action. The total area impacted by Phase 10 of the project would be reduced from 21.4 acres to 6.6 acres. The need for a flood protection berm along the west perimeter of Phase 10P would be eliminated. Eliminating Phase 10P would eliminate its direct impacts on the arroyo wash, and would avoid the downstream impacts on Fish Creek.

Vegetation and Habitat. Alternative 5 would proportionally reduce impacts on alluvial wash vegetation by reducing the amount of mining. Otherwise, the impacts on vegetation and habitat would be as described for the Proposed Action. Mitigation measures would be the same as identified for the proposed action.

Special-status Plants. The potential impacts of Alternative 5 on special-status plants would be the same or slightly less than the impacts described for the Proposed Action because the area to be mined is slightly smaller. No listed species or BLM sensitive species would be affected.

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Effects to annual rock-nettle and other species could be slightly less, depending on local extent of occupied habitat during a given year. This effect would be relatively minor and no mitigation is necessary.

General Wildlife Effects. The impacts of Alternative 5 on wildlife would the same as described for the Proposed Action, but would be quantitatively slightly less due to the reduced quarry footprint. This alternative would reduce the northernmost extent of the quarry and thus could have slightly less impact to localized wildlife movement across the canyon, between mountainous habitat to the east and west. Mitigation measures would be the same as identified for the proposed action.

Threatened or Endangered Wildlife. The impacts of Alternative 5 on PBS and barefoot banded gecko would the same as described for the Proposed Action, but may be quantitatively slightly less due to the reduced quarry footprint. This alternative would reduce the northernmost extent of the quarry and thus could have slightly less impact to localized wildlife movement across the canyon, between mountainous habitat to the east and west. However, the primary connection between the two habitat areas is south of the quarry expansion area, in the mountains above the upper watershed. This alternative, like the Proposed Action, would not affect Swainson’s hawk or desert pupfish. Mitigation measures for threatened or endangered wildlife would be the same as identified for the proposed action.

Other Special-status Wildlife. The impacts of Alternative 5 on other special-status wildlife would be qualitatively the same as described for the Proposed Action, but quantitatively slightly reduced due to the slightly smaller quarry area. Mitigation measures for special-status wildlife would be the same as identified for the proposed action.

3.4.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative

Approximately 11.87 million tons less ore would be mined under this alternative than under the Proposed Action. At a maximum permitted production of 1.92 million tons per year, this alternative would reduce projected mine life presented in the Proposed Action by 6.18 years. Under this alternative area disturbance would be 45.09 acres, compared with 53.71 acres under the Proposed Action.

Vegetation and Habitat. The impacts of Alternative 6 on vegetation and habitat would be the same as described for the Proposed Action, but the magnitude of the impacts would be slightly less on alluvial wash vegetation because of the reductions in Phases 4 and 5. Mitigation measures would be the same as identified for the Proposed Action.

Special-status Plants. The potential impacts of Alternative 6 on special-status plants would be the same or slightly less than the impacts described for the Proposed Action because the area to

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be mined is slightly smaller. No listed species or BLM sensitive species would be affected. Effects to annual rock-nettle and other species could be slightly less, depending on local extent of occupied habitat during a given year. This effect would be relatively minor and no mitigation is necessary.

General Wildlife Effects. The impacts of Alternative 6 on wildlife would the same as described for the Proposed Action but would be quantitatively slightly less due to the reduced quarry footprint. Mitigation measures would be the same as identified for the proposed action.

Threatened or Endangered Wildlife. The impact of Alternative 6 on PBS and barefoot banded gecko would the same as described for the Proposed Action, but may be quantitatively slightly less due to the reduced quarry footprint. This alternative, like the Proposed Action, would not affect Swainson’s hawk or desert pupfish. Mitigation measures for threatened or endangered wildlife would be the same as identified for the proposed action.

Other Special-status Wildlife. The impacts of Alternative 6 on other special-status wildlife would be qualitatively the same as described for the Proposed Action, but quantitatively slightly reduced due to the slightly smaller quarry area. Mitigation measures for special-status wildlife would be the same as identified for the proposed action.

3.4.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative

Approximately 2.33 million tons less gypsum would be mined under this alternative than under the Proposed Action. At a maximum permitted production of 1.92 million tons per year, this alternative would reduce projected mine life by 1.21 years compared with the Proposed Action. The removal of these three phases would realign the proposed storm water berm such that it would be nearly perpendicular to flow in the main channel along three significant sections where the phases are proposed for removal (from approximately 300 to 1,300 feet long).

Vegetation and Habitat. Alternative 7 would slightly reduce mining impacts on upland and alluvial wash vegetation (primarily creosote bush scrub and sparsely vegetated sandy wash) by deleting Phases 2P and 3P. Other impacts on vegetation and habitat would be as described for the Proposed Action. Mitigation measures would be the same as identified for the proposed action.

Special-status Plants. The potential impacts of Alternative 7 on special-status plants would be the same or slightly less than the impacts described for the Proposed Action. No listed species or BLM sensitive species would be affected. Effects to annual rock-nettle and other species could be slightly less, depending on local extent of occupied habitat during a given year. This effect would be relatively minor and no mitigation is necessary.

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General Wildlife Effects. The impacts of Alternative 7 on wildlife would the same as described for the Proposed Action, but to a slightly less degree due to the reduced quarry footprint. Mitigation measures would be the same as identified for the proposed action.

Threatened or Endangered Wildlife. The impacts of Alternative 7 on PBS and barefoot banded gecko would the same as described for the Proposed Action, but may be quantitatively slightly less due to the reduced quarry footprint. This alternative, like the Proposed Action, would not affect Swainson’s hawk or desert pupfish. Mitigation measures for threatened or endangered wildlife would be the same as identified for the proposed action.

Other Special-status Wildlife. The impacts of Alternative 7 on other special-status wildlife would be qualitatively the same as described for the Proposed Action, but quantitatively slightly reduced due to the slightly smaller quarry area. Mitigation measures for special-status wildlife would be the same as identified for the proposed action.

3.4.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative

Alternative 8, described in Chapter 2 and Figure 2-9, is the Proposed Action but with a reduced mining footprint in Phases 7 and 8 and corresponding modifications to the berm.

Impacts would be reduced from 32.12 acres under the Proposed Action to 20.05 acres. The overall mining footprint would be reduced, thereby decreasing potential mining beneath the valley alluvium where gypsum ore has been determined to be most prevalent.

Approximately 13.04 million tons less gypsum would be mined under this alternative than under the Proposed Action. At a maximum permitted production of 1.92 million tons per year, this alternative would reduce projected mine life by 6.79 years compared to the Proposed Action

Vegetation and Habitat. Alternative 8 would slightly reduce impacts from Phases 7 and 8 to alluvial wash vegetation (primarily creosote bush scrub and catclaw acacia thorn scrub), and other impacts on vegetation and habitat would be as described for the Proposed Action. Mitigation measures would be the same as identified for the proposed action.

Special-status Plants. The potential impacts of Alternative 8 on special-status plants would be the same or slightly less than the impacts described for the Proposed Action. No listed species or BLM sensitive species would be affected. Effects to annual rock-nettle and other species could be slightly less, depending on local extent of occupied habitat during a given year. This effect would be relatively minor and no mitigation is necessary.

General Wildlife Effects. The impacts of Alternative 8 on wildlife would the same as described for the Proposed Action but would be quantitatively slightly less due to the reduced quarry footprint. Mitigation measures would be the same as identified for the proposed action.

Threatened or Endangered Wildlife. The impacts of Alternative 8 on PBS and barefoot banded gecko would the same as described for the Proposed Action but may be quantitatively slightly less due to the reduced quarry footprint. This alternative, like the Proposed Action, would not

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affect Swainson’s hawk or desert pupfish. Mitigation measures for threatened or endangered wildlife would be the same as identified for the proposed action.

Other Special-status Wildlife. The impacts of Alternative 8 on other special-status wildlife would be qualitatively the same as described for the Proposed Action, but quantitatively slightly reduced due to the slightly smaller quarry area. Mitigation measures for special-status wildlife would be the same as identified for the proposed action.

3.4.5 Cumulative Effects

3.4.5.1 Geographic Scope of Cumulative Effects Analysis

The geographic scope of the cumulative effects analysis is based on the vegetation, habitat, and land uses at the Quarry expansion and Plant sites, the surrounding geography, and the characteristics of potentially affected biological resources. The proposed Quarry expansion is located within and adjacent to federal, State, and county lands that are largely undeveloped, except in the Imperial Valley where agriculture is dominant. These undeveloped lands support native vegetation and habitat primarily of desert shrublands, and desert transitional montane habitats such as semi-desert chaparral and conifer woodlands at higher elevations.

The geographic extent for the analysis of cumulative effects to vegetation and wildlife is as follows.

 Vegetation, wildlife habitat, special-status plants, common wildlife, and wide-ranging special-status wildlife: A 20-mile radius surrounding the project area associated with the Proposed Action and the IID pipeline route that would be constructed under Alternatives 3 and 4.  PBS: The designated critical habitat and recovery regions within San Diego and Imperial counties, as identified by USFWS.  Desert pupfish: The watershed supporting the USFWS-designated critical habitat within Imperial County, as identified by USFWS.  Flat-tailed horned lizard: Western population as identified by USFWS.  Burrowing owl: The geographic extent of burrowing owls in western Imperial County (including the lands west of the Salton Sea and the Imperial Valley).

3.4.5.2 Timeframe of the Cumulative Effects Analysis

The timeframe of the cumulative effects analysis is considered to be the life of the Proposed Action or Alternatives, estimated at 73 years of Quarry operations, an additional 7 years of Plant operations, and an additional estimated 10 years for facilities decommissioning and final reclamation/revegetation.

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3.4.5.3 Past, Present, and Reasonably Foreseeable Actions

A cumulative effect on vegetation or wildlife would occur if the Proposed Action or its alternatives, combined with the past, present, and reasonably foreseeable projects identified in this section, would affect the resource even where the Proposed Action or its alternatives alone would not. Examples of cumulative effects include special-status biological resources becoming limited in geographic extent or population sizes within the cumulative analysis area due to combined effects of the Proposed Action and one or more other projects.

Most of the cumulative scenario projects would be located within developed or agricultural areas and would contribute minimally, if at all, to the potential cumulative effects on desert vegetation communities or wildlife resources. The cumulative scenario projects considered in this analysis of cumulative biological resource effects are:

 Vista Verizon Tower (Project 5 in Appendix F)  Big Rock Solar (Project 18)  SDG&E Switchyard from Ocotillo Express Modification (Project 40)  Ocotillo Wind Energy Facility (Project 41)  Granite/IVA ROW Assignment (Project 42)  Sunrise Powerlink

Vegetation and Habitat. The Proposed Action and its alternatives, combined with the past, present and reasonably foreseeable actions identified above, would cause permanent or long-term loss of desert vegetation and habitat in the region. These effects would be mitigated through reclamation measures identified in Section 3.4.6, and through critical habitat conservation, also described in Section 3.4.6.

The cumulative scenario projects are located in desert valley areas. They would not add to the effects of the proposed Quarry expansion, which would occur in the lower mountain slopes and adjacent alluvial wash because vegetation and habitat in the two areas are distinctly different from one another.

The temporary effects on vegetation and habitat of the Quarry water and electrical line, the existing Plant pipeline removal, its replacement, and the IID waterline, in combination with the cumulative projects, would impact the desert valley, where the cumulative scenario projects are also located. The past, present, and reasonably foreseeable future projects are subject to their own project-specific mitigation requirements, and any future projects subject to the Desert Renewable Energy Conservation Plan (DRECP) would incorporate project-specific mitigation measures and/or applicable DRECP Conservation Management Actions (CMAs). The effects of pipeline construction for the proposed Project and its alternatives on valley floor vegetation and habitat would be minimal, as described in Section 3.4 above, and temporary, limited to the duration of construction, with longer-term habitat impacts mitigated through measures identified in Section 3.4.6. With implementation of these mitigation measures, the cumulative contribution to impacts on vegetation and habitat from the Proposed Action or the alternatives would not be substantial.

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Common Wildlife. The effects of the Proposed Action and its alternatives on wildlife, combined with the effects of the past, present and reasonably foreseeable actions, would include permanent or long-term loss of habitat in the quarry expansion areas and on the desert valley floor, displacement of wildlife, and potential mortality during construction of those wildlife that are poor dispersers such as snakes, lizards, and small mammals. The past, present, and reasonably foreseeable future projects are subject to their own project-specific mitigation requirements, and any future projects subject to the DRECP would incorporate project-specific mitigation measures and/or applicable CMAs. The combined effect to common—that is, non-special-status—wildlife is small because these species are common and wide-ranging in the region. With incorporation of mitigation measures identified in Section 3.4.6, particularly measures 3.4-2, 3.4-3, and 3.4-4 which require monitoring and reporting, environmental training, and multiple measures to minimize or avoid wildlife impacts, the contributions of the Proposed Action or its alternatives to cumulative common wildlife effects would be minimal.

Special-status plants. This project would incorporate Mitigation Measure 3.4-10 for the alternatives that would include the IID pipeline. Otherwise, the project would have a minimal effect on special-status plants, and no effect on listed threatened or endangered plants or BLM sensitive plants (see analysis of special-status plant impacts in Sections 3.4.4.1 and 3.4.4.3). The project would not contribute cumulatively to the effects on special status plants of the five projects identified in Section 3.4.5.3.

Special-status fish and wildlife. The current and reasonably foreseeable projects within the cumulative effects analysis area, when combined with the Proposed Action or its alternatives, could result in larger impacts on some of the same special status fish and wildlife species as the Proposed Action. Cumulative effects on these species could include habitat loss; displacement, injury, or mortality of individual animals; indirect effects of human disturbance; or changes in habitat quality.

 PBS and critical habitat. The critical habitat of PBS in this vicinity is defined in USFWS’ final rule revising its 2001 designation (Federal Register 74(70):17288-17365. April 14, 2009). Four projects identified in the cumulative scenario (the SDG&E Switchyard from Ocotillo Express Modification, Sunrise Powerlink Transmission Project, Ocotillo Wind Energy Facility, and the Granite/IVA ROW Assignment) are located within or near the PBS recovery units identified in the USFWS 2000 Recovery Plan for PBS. The Sunrise Powerlink project is partially located within designated critical habitat for PBS. The Proposed Action and its alternatives would avoid take and minimize effects on PBS through a series of avoidance and monitoring measures. Over time, Quarry reclamation would rectify the direct effects to both suitable habitat and critical habitat. Consultation with the USFWS may also result in minimization of adverse effects to designated critical habitat (Section 3.4.6). By incorporating the proposed mitigation measures, the net effect of this project on PBS and its critical habitat would be minimized. Similarly, the cumulative scenario projects identified each included mitigation to minimize its net effect. Therefore, with incorporation of the mitigation measures in Section 3.4.6, the contribution of the Proposed Action or its alternatives to cumulative effects on PBS and its critical habitat would be minor.

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 Desert pupfish. The Proposed Action or its alternatives would not affect desert pupfish (see analysis of desert pupfish impacts in Section 3.4.4.1); and therefore, would not contribute to any cumulative effects of the past, present and reasonably foreseeable actions identified in Section 3.4.5.3.  Sensitive reptiles. The pipeline components of the Proposed Action and its alternatives could affect the flat-tailed horned lizard or (less likely) Colorado desert fringe-toed lizard by causing displacement, injury, or mortality to individual animals, or by causing temporary disturbance to its dune and sandfield habitat. These potential effects would be minimized and mitigated through measures identified in Section 3.4.6, including measures required under the Flat-tailed Horned Lizard Rangewide Management Strategy, 2003 Revision. By incorporating these mitigation measures, the net effect of the Proposed Action or its alternatives on flat-tailed horned lizard, Colorado Desert fringe-toed lizard, and both species’ habitat would be minor. Additionally, the USFWS (2011b) determined that flat-tailed horned lizard populations within Management Areas are not low or declining and that most populations, with the exception of occurrences in the Coachella Valley, are not likely to become endangered in the foreseeable future. The Rangewide Management Strategy reduces threats and promotes actions that benefit the flat-tailed horned lizard throughout its range, and “there is no information to suggest that the flat- tailed horned lizard population is declining or is in danger of becoming an endangered species in the foreseeable future.” Measures to conserve and mitigate flat-tailed horned lizard habitat will also benefit Colorado Desert fringe-toed lizard. The cumulative projects listed in Section 3.4.5.3 could affect both lizard species. The proposed project and its alternatives, as well as the cumulative scenario projects, are subject to avoidance and mitigation requirements of the flat-tailed horned lizard management strategy (Flat-tailed Horned Lizard Interagency Management Committee, 2003). The contribution of the Proposed Action and its alternatives, as mitigated, to cumulative effects on the flat-tailed horned lizard would be minimal. The combined effects of the proposed and cumulative projects, with required mitigation, would be minor.  Burrowing owl. One burrowing owl was observed outside the breeding season in the proposed Quarry expansion area. Burrowing owls could occur elsewhere on the Quarry expansion area or in the areas of other project components, although no other sign was observed. Mitigation measures identified herein would avoid take or other direct effects to burrowing owls. In addition, the effects of the Proposed Action or its alternatives on burrowing owl habitat would be mitigated through reclamation measures identified in Section 3.4.6. Burrowing owls in the agricultural regions of Imperial Valley appear to be declining in numbers, largely due to land use conversions and fallowing of formerly irrigated croplands, which provided highly productive foraging habitat for burrowing owls. These effects are cumulatively important to burrowing owls in the region but are distant from the area of the Proposed Action or its alternatives. The effects of the Proposed Action and its alternatives, as mitigated, would contribute negligibly to the cumulative decline in regional burrowing owl numbers.  Wide-ranging special-status wildlife. Wide-ranging species such as golden eagle (Aquila chrysaetos), desert kit fox, and American badger have not been observed in the

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Quarry or pipeline areas, but these species could use the sites for foraging, breeding, or as a travel route. The effects on wildlife of the Proposed Action or its alternatives, combined with the past, present and reasonably foreseeable actions, could include permanent or long-term loss of habitat or displacement of individuals from disturbed areas. Mortality or injury is unlikely because these species would disperse away from vehicles and equipment. The five projects identified in Section 3.4.5.3 could result in similar effects. However, the combined effect of these projects on wide-ranging, special-status wildlife is limited because extensive undisturbed habitat areas remain throughout the region (e.g., in Anza-Borrego Desert State Park and BLM Wilderness Areas). With the incorporation of the mitigation measures identified herein, the contribution of the Proposed Action or its alternatives to cumulative, wide-ranging effects on special-status wildlife would be minimal.

Migratory birds. The Proposed Action or its alternatives could cause injury or mortality to migratory birds, their nests, eggs, or nestlings. Mitigation measures identified in Section 3.4.6 would avoid these potential effects by requiring pre-construction surveys in work areas, nest buffers, and other measures. The Proposed Action and its alternatives do not present a collision or electrocution hazard for migratory birds. With the incorporation of mitigation identified in Section 3.4.6, the contribution of the Proposed Action or its alternatives would avoid take of birds, eggs, and nestlings, and therefore, the contribution to cumulative effects on migratory birds is minimal.

3.4.6 Mitigation Measures

Mitigation measures were proposed in the 2006 Draft EIR/EIS to address potential impacts on vegetation and wildlife resources. No changes to the mitigation measures (3.4-1 through 3.4-4, and 3.5-1a-f and 3.5-2) as listed in Appendix E are proposed. New recommendations from the 2018 BRTR, based on new surveys, information, and regulations are proposed. These are listed below.

Mitigation Measure 3.4-5: Integrated Weed Management Plan. USG will prepare and implement an integrated weed management plan to control invasive weeds including tamarisk (Tamarix) and fountain grass (Pennisetum) in cooperation with the BLM and County of Imperial. The plan will include procedures to help minimize the introduction of new weed species, an assessment of the invasive weed species known within the area associated with the Proposed Action, and procedures to control their spread on site and to adjacent offsite areas. This plan will be submitted to the BLM and County of Imperial for review and approval prior to the start of construction and will be implemented for the life of the Proposed Action.

Mitigation Measure 3.4-6: Mining Activity Monitoring and Reporting. Prior to the beginning of any Quarry expansion activities, USG will identify a Designated Biologist and may additionally identify one or more Biological Monitors to support the Designated Biologist. The Designated Biologist and Biological Monitors will be subject to approval by the BLM and USFWS. The Designated Biologist will be in direct contact with BLM and USFWS.

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The Designated Biologist or Biological Monitor will have the authority and responsibility to halt any project activities that are in violation of the conservation and mitigation measures. To avoid and minimize effects to biological resources, the Designated Biologist and/or Biological Monitor will be responsible for the following:

 The Designated Biologist will notify BLM’s Authorized Officer and USFWS at least 14 calendar days before the initiation of Quarry expansion of new ground-disturbing activities.  The Designated Biologist or Biological Monitor will conduct pre-construction clearance surveys and will be on-site during any Quarry expansion activities or other new ground- disturbing activities (e.g., clearing spoils stockpile areas) and will be responsible for ensuring that no Quarry expansion activities are conducted while PBS are within a 0.25-mile radius of the activity.  The Designated Biologist or Biological Monitor will immediately notify BLM’s Authorized Officer and USFWS in writing if USG does not comply with any conservation measures including, but not limited to, any actual or anticipated failure to implement conservation measures within the periods specified.  The Designated Biologist or Biological Monitor will visit the Quarry site periodically (no less than once per month) throughout the life of the project to administer the Worker Education Awareness Program (WEAP) and ensure compliance with the plans and programs listed below. o The Designated Biologist will submit an annual compliance report no later than January 31 of each year to BLM’s Authorized Officer throughout the life of the project documenting the implementation of these programs/plans as well as compliance/non-compliance with each conservation measure: (1) Integrated Weed Management Plan; (2) WEAP; (3) Reclamation Plan; (4) Wildlife Mortality Reporting Program; and (5) PBS Monitoring Plan.

Mitigation Measure 3.4-7: WEAP. Prior to project approval, USG will develop a WEAP, to be implemented upon final approval by BLM and USFWS. The WEAP will be available in English and Spanish. The WEAP will be presented to all workers on the project site throughout the life of the project. Multiple sessions of the presentation may be given to accommodate training all workers. Wallet-sized cards summarizing the information will be provided to all construction, operations, and maintenance personnel. The WEAP will be approved by the BLM, USFWS, and CDFW, and will include the following: (1) Descriptions of special-status wildlife of the region, including PBS, and including photos and how to identify adult and sub-adult male and female PBS; (2) The biology and status of special-status species of the area, including PBS; (3) A summary of the avoidance and minimization measures and other conservation measures; (4) An explanation of the PBS observation log (see PBS-2), including instruction on correctly filing data; (5) An explanation of the flagging or other marking that designates authorized work areas; and (6) Actions and reporting procedures to be used if any wildlife, including PBS is encountered.

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Mitigation Measure 3.4-8: Wildlife Impact Avoidance and Minimization Measures. USG will implement the following measures throughout the life of the project (e.g., Plant and Quarry operations).

 To the extent feasible, initial site clearing for Quarry expansion, pipeline construction, or other activities (e.g., clearing spoils stockpile areas) will be conducted outside the nesting season (January 1 through August 31) to avoid potential take of nesting birds or eggs.  The Designated Biologist or Biological Monitor will conduct pre-construction clearance surveys no more than seven days prior to initial site clearing for Quarry expansion or pipeline construction. To the extent feasible, special-status wildlife (e.g., reptiles) will be removed from “harm’s way” prior to site clearing. If an active bird nest, including active burrowing owl burrows are present, the biologist in consultation with CDFW will mark a suitable buffer area around the nest and project activities will not proceed within the buffer area until the nest is no longer active.  For project activities in windblown sand habitats on pipeline routes, the Designated Biologist or Biological Monitor shall be present in each area of active surface disturbance throughout the work day. The Designated Biologist or Biological Monitor will survey work areas immediately prior to ground-disturbing activities and will examine areas of active surface disturbance periodically (at least hourly when surface temperatures exceed 85ºF) for the presence of flat-tailed horned lizard or Colorado Desert fringe-toed lizard. In addition, all potential wildlife hazards (e.g., open pipeline trenches, holes, or other deep excavations) shall be inspected for the presence of any wildlife, particularly including the flat-tailed horned lizard or Colorado Desert fringe-toed lizard, prior to backfilling.  The Designated Biologist or Biological Monitor will be on-site during any Quarry expansion activities or other new ground-disturbing activities (e.g., clearing spoils stockpile areas) and will be responsible for ensuring that no Quarry expansion activities are conducted while PBS are within a 0.25-mile radius of the activity.  Speed limits along all access roads will not exceed 15 miles per hour.  Avoid or minimize night lighting by using shielded directional lighting pointed downward, thereby avoiding illumination of adjacent natural areas and the night sky.  The boundaries of all areas to be newly disturbed (including Quarry expansion areas, staging areas, access roads, and sites for temporary placement of construction materials and spoils) will be delineated with stakes and flagging prior to disturbance. All disturbances, vehicles, and equipment will be confined to the flagged areas. The Biological Monitor will be on the site to ensure that no ground-disturbing activities occur outside the staked area during initial Quarry expansion or ground disturbance.  Spoils will be stockpiled only within previously disturbed areas, or areas designated for future disturbance (including spoils areas designated in the PoO).  No potential wildlife entrapments (e.g., trenches, bores) will be left uncovered overnight. Any uncovered pitfalls will be excavated to 3:1 slopes at the ends to provide wildlife

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escape ramps. Covered pitfalls will be covered completely to prevent access by small mammals or reptiles.  To avoid wildlife entrapment (including birds) all pipes or other construction materials or supplies will be covered or capped in storage or laydown area, and at the end of each work day in construction, Quarrying and processing/handling areas. No pipes or tubing of sizes or inside diameters ranging from 1 to 10 inches will be left open either temporarily or permanently.  No anticoagulant rodenticides, such as Warfarin and related compounds (indandiones and hydroxycoumarins), may be used within the project site, on off-site project facilities and activities, or in support of any other project activities.  Avoid wildlife attractants. All trash and food-related waste shall be placed in self-closing raven-proof containers and removed regularly from the site to prevent overflow. Workers shall not feed wildlife. Water applied to dirt roads and construction areas for dust abatement shall use the minimal amount needed to meet safety and air quality standards to prevent the formation of puddles, which could attract wildlife. Pooled rainwater or floodwater within quarries will be removed to avoid attracting wildlife to the active work areas.  Any injured or dead wildlife encountered during project-related activities shall be reported to the Designated Biologist, Biological Monitor, CDFW, or a CDFW-approved veterinary facility as soon as possible to report the observation and determine the best course of action. For special-status species, the Designated Biologist or Biological Monitor shall notify the BLM, USFWS, and/or CDFW, as appropriate, within 24 hours of the discovery.

Mitigation Measure 3.4-9: Burrowing Owl Avoidance. If an active burrowing owl burrow is observed within a work area at any time of year, the Designated Biologist or Biological Monitor, in coordination with BLM, will designate and flag an appropriate buffer area around the burrow where project activities will not be permitted. The buffer area will be based on the nature of project activity and burrowing owl activity (i.e., nesting vs. wintering). The Designated Biologist or Biological Monitor will continue to monitor the site until it is confirmed that the burrowing owl(s) is no longer present. If avoidance of quarrying or pipeline construction within the buffer area is infeasible, Burrowing Owls may be excluded from an active wintering season burrow in coordination with CDFW and in accordance with CDFW guidelines, including provision of replacement burrows prior to the exclusion.

Mitigation Measure 3.4-10: Critical Habitat. To minimize impacts to PBS designated critical habitat, USG will conduct 1:1 on-site reclamation as specified in the Mining and Reclamation Plan for all project disturbance areas. Additionally, USG will acquire or set aside an area of designated critical habitat away from the Quarry’s operations for long-term wildlife habitat conservation, to minimize the loss of designated critical habitat within the Quarry. The habitat acquisition measure will be applicable for public lands directly affected by the Proposed Action. The acquired lands will consist of native desert vegetation within designated PBS critical habitat. Acquisition lands may include claim areas that are not disturbed by the mining project. Any

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lands proposed for acquisition to minimize the loss of critical habitat will be subject to review and approval by the BLM and Wildlife Agencies.

Mitigation Measure 3.4-11: PBS Monitoring and Reporting. USG will support the CDFW PBS monitoring and reporting program within the federal action area by funding the purchase of radio collars and the capture of ten (10) PBS in the Fish Creek and Vallecito Mountains Ewe Group areas, to provide location monitoring data over a ten-year period. The funding amount will be $157,115 (cost provided by CDFW), to be transferred to the CDFW program via a means agreed up by USG, BLM, and CDFW.

Mitigation Measure 3.4-12: PBS Avoidance and Minimization. USG will implement the following measures throughout the life of the project.

 New ground-disturbing activities (i.e., initial Quarry development, Quarry expansion, clearing for spoils deposition, or road construction in previously undisturbed areas) in designated critical habitat will not occur within PBS lambing season (January 1 through June 30) as defined in the Recovery Plan, except with prior approval by the Wildlife Agencies.  The Designated Biologist or Biological Monitor will be on-site during any Quarry expansion activities or other new ground-disturbing activities and will walk the perimeter of the Quarry expansion area and view surrounding habitat with binoculars, stopping work if PBS are within a 0.25-mile radius of the activity.  If a PBS enters an active work area, all heavy equipment operations will be halted until it leaves. Quarry staff may not approach the animal. If the animal appears to be injured or sick, USG will immediately notify USFWS and BLM.  Fencing installed anywhere within the Quarry area will be standard temporary construction fencing, silt fencing, or chain-link fence at least 7 feet tall. Any proposed permanent fencing design will be submitted for BLM and USFWS review and approval to confirm that the fence design is not likely to pose a threat to PBS.

Mitigation Measure 3.4-13. Future Quarry Phasing Notification and Review. USG will notify the BLM, CDFW, and USFWS 90 days prior to initiating future mining activities in the four phases nearest to the highest PBS occurrence and habitat connectivity areas (phases 6Bp, 7Bp, 8, and 9). Upon notification, the agencies will coordinate with USG to review PBS occurrence and activity in the vicinity obtained during the intervening years, as well as relevant documentation of Nelson’s bighorn sheep behavior near other mining operations. PBS avoidance and minimization measures may be revised as needed to conform to new information.

Mitigation Measure 3.4-14. Yuha Basin Tamarisk Removal. To offset the ground-disturbance effects of the Project’s pipeline construction within the Yuha Basin ACEC, USG will coordinate with the BLM to remove invasive tamarisk trees from the ACEC. By removing the invasive trees, groundwater availability will be improved for native vegetation, and the continued propagation and expansion of the tamarisk will be prevented.

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Mitigation Measure 3.4-15: Wiggins’ croton avoidance. This mitigation measure would only be applicable if Alternative 3 or Alternative 4 (incorporating Partial or full IID water supply) is selected. Prior to finalizing the pipeline alignment, a seasonal rare plant survey according to CNPS, CDFW, and BLM protocol, within the potential alignment and surrounding area shall be conducted. If Wiggin’s croton or any other BLM sensitive species or State- or federally-listed species is present, the pipeline route shall be designed to avoid the occurrence.

3.4.7 Residual Effects after Mitigation

With the implementation of mitigation measures identified in this section, residual effects to biological resources would be minor. The residual effects would consist of: (1) the net loss or degradation of vegetation and habitat on the project site; (2) the indirect effects of noise, lighting, and other disturbances to vegetation and habitat outside of the Quarry’s area of operations; and (3) the likely adverse effect on wildlife access within the Quarry area for many species, where the physical topography would be altered by Quarry bench/highwall design.

Implementation of the mitigation measures would not result in any additional effects to vegetation or wildlife resources. The Proposed Action and its alternatives (excluding the No Action Alternative) would affect vegetation and habitat, common wildlife, and special-status wildlife, including PBS. Mitigation measures required under prior County authorization (see Appendix E), as well as the mitigation measures identified in this Supplemental EIS, would substantially reduce the effects on these resources. The avoidance and minimization measures would assure the project’s compliance with State and federal laws, and that the project impacts after mitigation would not be substantially adverse.

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3.5 AIR QUALITY

The effects of the Proposed Action and its alternatives on Air Quality were analyzed in Chapter 3.6 of the 2006 Draft EIR/EIS. This section addresses the impacts of the Proposed Action and its alternatives on air quality in the affected environment that have changed or were not analyzed or addressed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

3.5.1 Affected Environment

The affected environment of the Proposed Action and its alternatives was presented in the 2006 Draft EIR/EIS (Chapter 3.6) and 2008 Final EIR/EIS. The Quarry is located in the central western portion of Imperial County adjacent to the Imperial County/San Diego County line. Imperial County is in the southeastern corner of California with the relatively flat Imperial Valley and the southern Salton Sea in the center surrounded by multiple mountain ranges to the east and west. The State and Federal air quality regulations have designated this region as the Salton Sea Air Basin (SSAB), whose Imperial County portion is under the jurisdiction of the Imperial County Air Pollution Control District (ICAPCD). The Federal Clean Air Act (CAA) of 1971 and the CAA Amendments (1977) established the National Ambient Air Quality Standards (NAAQS), which are promulgated by the Environmental Protection Agency (EPA). Per the CAA Waiver for California, the State of California may adopt its own more stringent California Ambient Air Quality Standards (CAAQS), which the California Air Resources Board (CARB) promulgates.

The NAAQS that have changed since the 2003 standards in the 2008 Final EIR/EIS are listed below:

 2015 - 8-hour ozone (O3) primary and secondary standards were lowered from 0.075 to 0.070 ppm, based on annual fourth-highest daily maximum 8-hour average concentration, averaged over 3 years. 3 3  2012 - Annual PM2.5 primary standard was lowered from 15 μg/m to 12.0 μg/m based on the annual mean, averaged over 3 years. The existing national 24-hour PM2.5 standards 3 3 (primary and secondary) were retained at 35 μg/m (down from 65 μg/m in 2003), based on the 98th percentile average over 3 years, as was the annual secondary standard of 15 μg/m3, based on the annual mean averaged over 3 years. th  2010 - New primary 1-hour SO2 standard of 75 ppb, based on the 99 percentile of 1-hour daily maximum concentrations, average over 3 years, was established and the existing 24-hour and annual primary standards were revoked; and

 2010 - National 1-hour primary standard for nitrogen dioxide (NO2) of 100 ppb was established.  2008 – Rolling 3-month average for lead (Pb) not to exceed 0.15 μg/m3.

The SSAB encompasses the entirety of Imperial County and the southeast portion of Riverside County and is generally an arid desert region, with a significant land area located below sea level. The hot and dry conditions experienced in the region are a result of a large, semi- permanent high-pressure area that dominates the Imperial Valley and the presence of the coastal

U.S. Gypsum Draft SEIS 3.5-1 July 2019 Chapter 3.5: Air Quality mountains to the west. The high pressure blocks most storms, except during the winter when the pressure is the weakest and tends to shift to the south. The coastal mountains tend to block moist air from entering the valley resulting in hot temperatures during the summer and dry weather year-round.

The SSAB contains relatively few major emissions sources, but may experience emissions transported from Mexicali, Mexico and from significant vehicular traffic, particularly near the two international ports of entry: Calexico West and Calexico East. Emissions sources within the SSAB consist of geothermal power generation, food processing, plaster and wallboard (gypsum) manufacturing, and other light industrial facilities. Additionally, the continuing fall in the water surface elevation of the Salton Sea is expected over time to generate fugitive dust originating from newly exposed sediments originally deposited underwater from agricultural runoff in the Salton Sea.

The two nearest monitoring stations to the project areas are in El Centro and Westmoreland, approximately 20 and 25 miles east from the project areas, respectively, as shown in Figure-3.5-1. The El Centro station measures ozone, PM10, PM2.5, and nitrogen dioxide. The Westmoreland station measures ozone and PM10. The monitoring stations are surrounded by urban and agricultural uses. By contrast, the Quarry is located in an isolated canyon surrounded by natural open space, and the Plant is located in a rural area with isolated houses adjacent to County Road 80.

The two monitoring stations are within the partial Imperial County NAAQS PM2.5 nonattainment area that encompasses the Imperial Valley in the southcentral urban and agricultural portions of the County (refer to Figure 3.5-1). The project sites are outside and to the west of this designated partial nonattainment area for PM2.5. The Imperial County areas within the SSAB are part of the Coachella Valley nonattainment areas for the PM10 and ozone NAAQS (see blue shaded area on Figure 3.5-1).

Table 3.5-1 lists the past four years (2014 – 2017) of available air pollutant monitoring data measured at the El Centro and Westmoreland monitoring stations. The data collected at these stations indicate that eight-hour concentrations of ozone exceeded the federal standard on an average of 13 days per year at the El Centro station. The eight-hour concentrations of ozone did not exceed the federal standard at the Westmoreland station. The federal PM10 standard was exceeded an average of about 5 days per year at the El Centro station, and 17 days per year at the Westmoreland station. PM2.5 and nitrogen dioxide federal standards were not exceeded at the El Centro station; those pollutants are not monitored at the Westmoreland station. Measurements of the other pollutants monitored did not exceed the air quality standards.

3.5.2 Methodology

The methodology for analyzing the effects of the Proposed Action and its alternatives on air quality is the same as discussed in the 2006 Draft EIR/EIS and the 2008 Final EIR/EIS. Activities associated with the construction and operation of the proposed expansion and modernization were evaluated to determine the potential to affect existing air quality conditions. Construction and operation emissions were assessed in accordance with EPA and ICAPCD air

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Table 3.5-1 Reported Air Quality Pollutant Concentrations As Monitored at Nearest Imperial County Monitoring Stations # of Days1 Maximum Federal State / Federal California Concentration Pollutant Primary Yr. Standards Exceeded Standard Standard Westmore- El Westmore- El land Centro land Centro CA / Fed CA / Fed

Missing Same Stds. Same Stds 0.080 Ozone 0.070 ppm 0.070 ppm 2014 (MSG) MSG 12 0.079 8-hour ave. 8-hour ave. 2015 0.061 0 11 (O3) 0.082 2016 0.068 0 11 0.092 2017 0.067 0 17

State / Fed. State / Fed. Particulate 2014 404 120 MSG / 25 90 / 0 matter < 10 2015 193 166 50 g/m3 150 g/m3 MSG / 18 44 / 6 2016 488 285 microns in 24-hr. avg. 24-hr. avg. MSG / 18 MSG / 10 diameter 2017 337 269 MSG / 8 MSG / 4 (PM10 )

Fed. Std. 2014 No 28 0 No State 35 g/m3 2015 Information 31 NIA 0 Standard 24-hr. avg. 2016 Available 31 0 Particulate 2017 (NIA) 23 0 matter < State / Fed. 2.5 microns Same Stds in diameter 2014 6.6 12 g/m3 12.0 µg/m3 0 (PM2.5 ) 2015 NIA 6.3 NIA annual annual 0 2016 9.5 0 2017 8.4 0 ppb ppb

2014 59 0/0 0.18 ppm 100 ppb 2015 NIA 59 NIA 0/0 (180 ppb) 1-hour ave. 2016 51 0/0 1-hour ave. Nitrogen 2017 49 0/0

ppm Dioxide 2014 0/0 0.007 (NO2) 0.030 ppm 0.053 ppm 2015 0/0 NIA 0.007 NIA annual ave. annual avg. 2016 0/0 0.005 2017 0/0 MSG

Source: CARB, 2018 Notes: 1 - PM measurements (samples) are usually collected every six days. Measured days counts the days that a measurement was greater than the level of the standard; Estimated days mathematically estimates how many days concentrations would have been greater than the level of the standard had each day been monitored. NIA: No Information Available; not measured. MSG: Missing or Insufficient data ppm: parts per million ppb: parts per billion g/m3: micrograms per cubic meter

U.S. Gypsum Draft SEIS 3.5-3 July 2019 Chapter 3.5: Air Quality quality regulations using CARB's Off-Road Emissions Model, CARB Off-Road Diesel Tier Emission Factors, and Off-road and On-Road Mobile Source Emissions' Factors (EMFAC per SCAQMD website) and emissions estimates were compared with applicable state and federal air quality standards.

Both the State of California and the Federal government have established health-based ambient air quality standards for six air pollutants. These pollutants include O3, CO, NO2, PM10 and subset PM2.5, and lead. In addition, the State has set standards for sulfates, hydrogen sulfide, vinyl chloride, and visibility-reducing particles. These standards are designed to protect the health and welfare of the populace with a reasonable margin of safety.

Specific geographic areas are classified as attainment, nonattainment, or unclassified areas for each pollutant, based on the comparison of measured data with Federal and State standards. The unclassified designation is used in an area that cannot be classified on the basis of available information as meeting or not meeting the standards.

The USEPA, under the provisions of the CAA, requires each State with regions or air basins that have not attained the NAAQS to prepare a State Implementation Plan (SIP), detailing how the standard for each pollutant not in attainment are to be met in each region or air basin. The USEPA reviews and approves the SIPs and has the power to impose sanctions for failure to submit a plan or carry out commitments in a plan.

CARB is the state agency responsible for the coordination and administration of both state and federal air pollution control programs in California. A key function of CARB is to coordinate and guide regional and local air quality planning efforts required by the California Clean Air Act (CCAA), and to prepare and submit required SIPs to the USEPA. ICAPCD shares responsibility with CARB for ensuring that all state and federal ambient air quality standards are achieved and maintained within the County through the development and enforcement of rules and regulations promulgated through the SIP process. The air pollution control district is also responsible for the inspection of stationary sources, monitoring of ambient air quality, and planning activities such as modeling and maintenance of the emissions inventory.

The SIP is a legal agreement between each State and the USEPA to commit resources to improving air quality. It serves as the template for conducting regional, cumulative, and project- level air quality analyses. Local air districts, such as the ICAPCD, prepare air quality attainment plans or management plans and submit them to CARB for review, approval, and incorporation into the applicable SIP. The air quality plans and strategies stated in the SIPs for achieving air quality standards on a regional or air basin basis incorporate existing and future modeled emissions, expected growth in population, traffic, and residential, commercial, industrial, and agricultural land uses. All of this information and air quality modeling is inherently a regional, cumulative assessment utilized to determine the future emissions levels and the control strategies and measures necessary to meet the NAAQS for a region.

A typical SIP includes the following (from Imperial County 2017 75 ppb 8-Hour Ozone SIP):

 Comprehensive emission inventory of all activities within the region;

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 Demonstration of reasonable further progress towards attainment;  Implementation of reasonably available control measures and technology and ow these will reduce future emissions;  Commitment to the New Source Review permitting program offsets at a ratio of 1.5 to 1 (reduction of 1.15 units of pollutant for every unit permitted);  A NAAQS attainment demonstration (modeling incorporating future emissions and control strategies and measures to attain NAAQS); and  Contingency measures in the event the area fails to meet attainment milestones.

3.5.3 Changes in Attainment Designations, Applicable Regulations, Plans, and Policies/Management Goals

Since the 2006 Draft EIR/EIS and the 2008 Final EIR/EIS were prepared, there have been changes to attainment designations, applicable regulations, plans or policies/management goals that affect air quality. The updated information as listed below are considered herein.

Attainment/Nonattainment Designations The Imperial County portion of the SSAB is currently designated as a nonattainment area (moderate) for the 8-hour Ozone (O3) NAAQS and CAAQS and nonattainment (serious) for PM10 NAAQS and CAAQS; this has not changed since the 2008 Final EIR/EIS (refer to blue shaded area in Figure 3.5-1). There were no defined attainment/nonattainment areas for PM2.5 in 2008. In 2009, the EPA designated a partial County area, the south central or valley area of Imperial County, as nonattainment (moderate) for PM2.5 NAAQS (refer to Figure 3.5-1). The County is in attainment for PM2.5 CAAQS. The project areas are located to the west of the partial County area and therefore are not within the area designated as nonattainment for PM2.5 NAAQS. However, for Alternatives 3 and 4, the proposed IID water supply pipeline to the West Side Canal would extend approximately 0.5 miles into the nonattainment area for PM2.5. The Imperial County portion of the SSAB is in attainment or unclassified with the NAAQS and CAAQS for the other applicable criteria pollutants. (Source: https://www.epa.gov/green-book, 2018)

Imperial County 2009 PM10 SIP and 2018 Redesignation Request and Maintenance Plan for PM10

The ICAPCD adopted the 2009 PM10 SIP in August 2009 that developed fugitive dust control measures (Regulation VIII). The EPA approved these Regulation VIII fugitive dust rules into the Imperial County portion of the California SIP in April 2013. The Regulation VIII fugitive dust rules (as updated) were based on the related 2005 Best Available Control Measure (BACM) analysis. Rules 800 – 805 of the Regulation VIII fugitive dust rules were included in the 2008 Final EIR/EIS. USG’s operations are required to comply with these regulations as applicable and updated enforceable through the ICAPCD.

The ICAPCD and CARB approved the "Imperial County 2018 Redesignation Request and Maintenance Plan for PM10" in late 2018. This document revises the 2009 PM10 SIP and requests redesignation of the Imperial Valley Planning Area as attainment. The Imperial Valley Planning Area is currently designated as a Serious nonattainment area for the PM10 NAAQS but can be

U.S. Gypsum Draft SEIS 3.5-5 July 2019 Chapter 3.5: Air Quality redesignated as attainment if, among other requirements, the USEPA determines that the NAAQS has been attained. A review of the PM10 monitoring data from 2014 through 2016 shows that, when excluding exceptional events (i.e. high wind driven dust storms), the Imperial Valley Planning Area did not violate the federal 24-hour PM10 standard.

Imperial County 2013 PM2.5 SIP (2006 24-Hour PM2.5)

The ICAPCD and the CARB approved the 2013 PM2.5 SIP in December 2014 and this SIP is under review by the EPA. The 2013 PM2.5 SIP concluded that the majority of the PM2.5 emissions result from emissions originating in Mexico. The SIP demonstrates attainment of the 2006 PM2.5 NAAQS “but for” transport of international emissions from Mexicali, Mexico. In accordance with the CAA, the PM2.5 SIP satisfies the attainment demonstration requirement satisfying the provisions of the CAA and the County is considered in attainment for CAAQS. However, the partial County area is currently considered nonattainment (moderate) for PM2.5 NAAQS. Note that the project areas are outside of this partial nonattainment area for PM2.5 except for 0.5 miles of the proposed IID water supply pipeline in Alternatives 3 and 4.

Imperial County 2017 75 ppb 8-Hour Ozone SIP The ICAPCD adopted the 2017 Ozone SIP in September 2017. This SIP is under review by the EPA. The SIP shows through photochemical grid modeling and a weight of evidence analysis that, but for emissions emanating from Mexico, the control measures included in the SIP are adequate to attain the 2008 Ozone standard and maintain this status through the July 20, 2018 attainment date and into the future.

The ICAPCD is working cooperatively with counterparts from Baja California Department of Environmental Protection to implement emissions reductions strategies and projects for air quality improvements at the border. The two states strive to achieve these goals through local input from government officials and representatives from academia, environmental organizations, and the general public. The Imperial Valley-Mexicali Air Quality Task Force (AQTF) has been organized to address unique issues in the binational Mexicali/Imperial Valley air shed. This group promotes regional efforts to improve the air quality monitoring network, to inventory emissions, and to develop air pollution transport modelling, as well to create programs and strategies to improve air quality.

Permits

The Plant and Quarry operate within the jurisdiction of the ICAPCD under a Title V Operating Permit issued in accordance with the provisions of 40 CFR Part 70 and Rule 900 of the ICAPCD. Three active permits (Nos. 1992, 2456, and 2834) issued by the ICAPCD to operate stationary sources at the Quarry are incorporated into the Plant’s and Quarry’s Title V Operating Permit (V-2834). The V-2834 permit renewal application was submitted on April 18, 2016 and is currently under review by the ICAPCD for renewal purposes. Per ICAPCD Rule 115, permits issued by the ICAPCD shall require compliance with all applicable air pollution control regulations of federal, state, and local agencies. USG is required to comply with its Title V Operating Permit and all other applicable ICAPCD rules as amended.

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3.5.4 Direct and Indirect Effects

Criteria and Dust Emissions – Overall

Since 2008, air quality regulations promulgated by the County SIPs have greatly reduced overall emissions from both stationary and mobile sources at the plant and quarry areas based on the emission estimates from modeling from the 2006 DEIS/EIR and 2019 emission estimates in this document (see Table 3.5-2. CARB passed regulations in 2007 for In-Use Off-Road Diesel- Fueled Vehicles to reduce oxides of nitrogen (NOx), diesel particulate matter (PM), and other criteria pollutant emissions from diesel-fueled vehicles driving off road. These regulations as updated through 2018, have substantially reduced the diesel emissions from the equipment in use at the Plant and Quarry, compared with the equipment assessed in the 2006 Draft EIR/EIS. These regulations require the following:

 Limits vehicle idling to no more than 5 consecutive minutes at one location, requires a written idling policy, and requires a disclosure when selling vehicles (California Code of Regulations Title 13, Section 2485; 2004 as amended);  Requires all vehicles to be reported to ARB (using the Diesel Off-Road Online Reporting System, DOORS) and labeled;  Restricts the adding of older vehicles into fleets starting on January 1, 2014; and  Requires fleets to reduce their emissions by retiring, replacing, or repowering older engines, or installing Verified Diesel Emission Control Strategies (VDECS; i.e., exhaust retrofits).

The Quarry mobile equipment emissions were updated utilizing the current fleet of vehicles, the engine Tier levels, and similar hours of operations as estimated in the 2006 Draft EIR/EIS. Appendix N includes tables with the updated estimated air quality emissions for the Proposed Action and its alternatives. Table 3.5-2 lists the existing conditions emission estimates from the 2006 Draft EIR/EIS (Table 3.6-12), and the Proposed Project column listing the updated emissions based on the 2018 fleet emission factors. The Emission Net Change row is the net emission increase or decrease between the Existing Conditions and the Proposed Action. The CEQA thresholds from the ICAPCD and whether or not the net emissions exceed these thresholds and would be considered significant are included to assess the Proposed Project with respect to the CAAQS and CEQA. These thresholds are similar to the de minimis thresholds in that they are pre-determined emission levels based on the SIP long-term requirements to meet air quality standards. If a project is less than the threshold, it is assumed to be less than significant and would not directly or cumulatively cause, contribute, or worsen violations to the region’s air quality standards.

General Conformity (CAA §176(c)(4)) ensures that the actions taken by federal agencies do not interfere with a state’s plans (SIPs) to attain and maintain NAAQS. The General Conformity rule ensures that federal activities do not cause or contribute to new violations of NAAQS; do not worsen existing violations of the NAAQS; and do not delay attainment of the NAAQS. In promulgating the General Conformity Regulations, USEPA recognized that the many entities of federal government take thousands of actions every day, most of which do not result in

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significant increases in emissions in nonattainment and maintenance areas. Therefore, USEPA promulgated de minimis emissions levels for each of the NAAQS pollutants. If the total direct and indirect emissions from the federal action are below the de minimis levels, the action is assumed to not cause, contribute, or worsen violations of the NAAQS. Since the air quality attainment or non-attainment status are for a region or air basin, the General Conformity Regulations are a cumulative assessment of the project’s emissions on NAAQS status in that region.

Table 3.5-2 USG Quarry Estimated Air Pollutant Emissions Existing Conditions and Proposed Project Operations (Updated 2019) (Based on 24 hours/day; 365 days/year) (Tons per Year) Existing Proposed Existing Proposed Existing Proposed Existing Proposed Existing Proposed NOx CO PM10 PM2.5 VOC SOURCE Quarry Stationary Sources1 & 2 (Title V ------108.36 56.99 22.54 11.85 ------permitted through ICAPCD) Quarry/Plant Mobile 57.75 18.54 22.11 36.33 6.02 0.62 6.02 0.57 4.03 1.24 Equipment/Trucks2 & 3 Haul/Access Roads2 ------92.88 58.05 19.32 12.07 ------(PM or dust only) Fugitive Dust Plus 0.03 0.05 0.11 0.18 121.95 160.88 25.37 33.46 ------Blasting Emissions2 Onsite Vehicles2 0.29 0.29 0.55 0.55 0.02 0.02 0.02 0.02 0.06 0.06 Emission Totals 58.07 18.88 22.77 37.06 329.23 276.54 73.27 57.97 4.09 1.30 Emission Net Change -39.19 14.29 -52.69 -15.3 -2.79 CEQA Thresholds per 25 100 27 100 25 ICAPCD CEQA Significant? No No No No No General Conformity Net Totals (no Row 1 -39.19 14.29 -1.35 -4.61 -2.79 permitted emissions)1 De minimis Levels Not Applicable; 100 70 100 100 (EPA) In attainment General Conformity Yes --- Yes Yes Yes 1 A conformity determination is not required for these PM emissions per: “(1) The portion of an action that includes major or minor new or modified stationary sources that require a permit under the new source review (NSR) program (Section 110(a)(2)(c) and Section 173 of the Act) or the prevention of significant deterioration program (title I, part C of the Act). 2 Quarry Stationary Sources’ emissions, Haul/Access Road PM emissions, Fugitive Dust plus blasting emissions, and Vehicle emissions from Table 3.6-12, 2006 Draft EIR/EIS; 3 Existing Quarry/Plant Emissions from Table 3.6-12, Draft 2006 EIR/EIS; Updated proposed 2018 Quarry/Plant Mobile Equipment (see Appendix N) PM2.5 estimated as 92% of PM10 for exhaust emissions and 20.8% of PM10 dust emissions (California Emission Inventory Data and Reporting System, Appendix A - List of PM2.5 Fractions)

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The de minimis levels of emissions in tons/year are based on an area’s designation and classification and are defined in 40 CFR 93 §153 as the minimum threshold for which a conformity determination must be performed if the project emissions exceed these levels. The determination of General Conformity would be “yes” if project emissions are less than the de minimis levels and “no” if emissions exceed the de minimis levels (see Table 3.5-2).

3.5.4.1 Alternative 1: Proposed Action

Table 3.5-3 shows that the Proposed Action’s annual emissions for nitrogen oxide and reactive organic gases (ROGs), also termed volatile organic compounds (VOCs), including emissions for the annual tamarisk removal program proposed for the surface disturbance effects in the Yuha Basin ACEC (see Mitigation Measure 3.4-14, Section 3.4.6), would not exceed the de minimis levels established to demonstrate General Conformity with the CAA. Not exceeding the General Conformity de minimis emissions thresholds means a General Conformity Determination is not required for the Proposed Action and ensures that the Proposed Action would not interfere with the SIP for ozone or particulate matter (both PM2.5 and PM10) in Imperial County. This would include direct impacts within the nonattainment areas where the project sites are located and indirect impacts to the adjacent PM2.5 nonattainment area to the east as included in Tables 3.5-2 and 3.5-3.

The 2006 Draft EIR/EIS identified proposed mitigation measures to implement emission reduction measures and regulations. Mitigation Measures 3.6-1a through 1c would require equipment maintenance and operations in compliance with current CARB and ICAPCD regulations to remain in effect. Mitigation Measure 3.10-1 would require compliance with current OSHA regulations and the National Emission Standards for Hazardous Air Pollutants, including standards for asbestos. Mitigation Measure 3.10-2 was developed to address the potentially hazardous air quality effects associated with removal of the existing, asbestos- containing water pipeline. An Abatement Work Plan and Quality Control Plan for the U.S. Gypsum Water Transite Pipe Removal was prepared and would be implemented in accordance with all current EPA, OSHA, California Department of Industrial Relations, Division of Occupational Safety and Health (Cal OSHA), Asbestos and Carcinogen Unit, and local city/county rules for asbestos abatement work, PPE, waste management, transportation and landfill disposal.

Air quality permitting or compliance procedures for the Quarry and Plant have not changed since preparation of the previous environmental documents. Under the Proposed Action, the Quarry would continue to operate under the jurisdiction of the ICAPCD. The facility’s Title V Operating Permit (V-2834) renewal application is currently under review by the ICAPCD. The ICAPCD conducts inspections of the Quarry facility’s property and equipment twice a year for compliance purposes. The ICAPCD also verifies annual source testing completed by a licensed third-party contractor to satisfy permit conditions for PTO 2456. In addition, USG is required by the

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Table 3.5-3 USG Quarry Total Emissions - Mobile and Fugitive Proposed Project Operations and Alternatives (Tons per Year) SOURCES NOx CO PM10 PM2.5 SOx VOC Quarry Mobile Sources (Alt 1, 3 ,4) (from Table -39.19 14.29 -1.35 -4.61 -5.95 -2.79 3.5-2 above) Locomotive1 13.46 1.33 0.34 0.31 1.29 0.50 (Alt 1, 3, 4) Alt. 1 Construction2 Quarry Pipeline & 6.55 4.33 7.47 1.28 0 0.54 Plant/Wells Pipeline Removal/Replacement Alt. 3 Construction2 Quarry Pipeline, Plant/Wells Pipeline 8.77 5.83 10.14 1.89 0 0.74 Removal/Replacement & IID Water Line; 2 water ponds & 2 tanks Alt. 4 Construction2 Quarry Pipeline, Plant/Wells Pipeline 8.85 6.16 8.86 1.78 0 0.91 Removal; IID Water Line; 4 evaporation ponds; & 4 tanks Annual Pond 0.02 0.16 <0.01 <0.01 0 <0.01 Maintenance Alt. 3 Annual Pond 0.26 1.81 0.01 0.01 0 0.04 Maintenance Alt. 4 Mitigation (Tamarisk 0.62 0.34 0.03 0.03 0 0.16 removal)3 Alt. 1, 3, 4 Net Emissions Change Alternative 1 -25.11 15.96 -0.98 --4.27 -4.66 -2.13 Alternative 2 No Change No Change No Change No Change No Change No Change Alternative 3 -25.09 16.12 -0.98 --4.27 -4.66 -2.09 Alternative 4 -24.85 17.77 -0.97 --4.26 -4.66 -1.97 Not Not De Minimis Rates 100 Applicable; 70 100 Applicable; 100 (EPA) In attainment In attainment In General Conformity Yes --- Yes Yes --- Yes CEQA Thresholds 25 100 27 100 27 25

CEQA Significant? No No No No No No 1 - Locomotive emissions from Table 3.6-11 (2006 Draft EIR/EIS) 2 - Short-term construction emissions only for less than one year; therefore, not added to annual totals. 3 - Assume Mitigation (tamarisk removal) to be an annual activity for Alt. 1, 3, & 4. Operations - Assume 5 days/week; 8 hours/day; and 40 weeks/year or 200 days (no summer operations). PM10 and PM2.5 include fugitive dust from Table 3.6-8 (2006 Draft EIR/EIS). See Appendix N for Air Quality Emission Tables for criteria emissions and Table 3.6-8 (2006 Draft EIR/EIS) for fugitive dust or PM emissions during pipeline construction.

July 2019 3.5-10 U.S. Gypsum Draft SEIS Chapter 3.5: Air Quality permit’s Special Provisions to monitor visible emissions, record pressure drop readings for all baghouses (PM emissions control equipment), and record processing throughput as detailed in the Title V Operating Permit. All permit conditions are currently being met. The Quarry is currently in compliance with respect to air quality permitting for 2018 based on their submittal of their renewal application.

3.5.4.2 Alternative 2: No Action Alternative

The potential effects on air quality as analyzed and described in Section 3.6 of the 2006 Draft EIR/EIS and 2008 EIR/EIS are unchanged. All ICAPCD permit conditions are currently being met. The Quarry facility is currently in compliance for 2018. New impacts to air quality would not occur, and mitigation would not be required.

3.5.4.3 Alternative 3: Partial IID Water Supply Alternative

The data in Table 3.5-3 indicate that neither the short-term, construction-related effects nor the operations and maintenance effects of this alternative would result in significant, additional adverse impacts on air quality. New pumps required to deliver canal water to the pipeline would be small, electric pumps (3-50 HP pumps) that would use commercial power and would operate under a Permit to Operate by the ICAPCD. These small pumps would have a negligible effect on the overall emissions which are less than the 2006 Draft EIR/EIS. The ICAPD would annually review compliance with the permit. The power usage would be offset by reductions in pumping from the existing wells at Ocotillo. The settling ponds would require annual maintenance to remove and dispose of settled solids. It is estimated that this would require three 8-hour days per year for a scraper and loader, and approximately fifteen 30-mile round trips by truck per year.

No adverse effects on the existing ambient air quality conditions would occur from implementing the Partial IID Water Supply Alternative. Additional emission reduction measures besides those as discussed under Alternative 1 – Proposed Action, would not be required.

3.5.4.4 Alternative 4: Full IID Water Supply Alternative

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The data in Table 3.5-3 indicate that neither the short-term, construction-related effects nor the operations and maintenance effects of this alternative would result in significant, additional adverse impacts on air quality. This would include direct impacts within the nonattainment areas where the project sites are located and indirect impacts to the adjacent PM2.5 nonattainment area to the east. New pumps required to deliver canal water to the pipeline would be small, electric pumps (3-50 HP pumps) that would use commercial power and would operate under a Permit to Operate by the ICAPCD. These small pumps would have a negligible effect on the overall emissions which are less than the 2006 Draft EIR/EIS. Compliance with the permit would be reviewed annually by the ICAPCD. The power usage would be offset by the elimination of pumping from the existing wells at Ocotillo. The settling ponds would require annual maintenance to remove and dispose of settled solids. It is estimated that this would require 33 8-hour days per year for a scraper and loader, and approximately 165 30-mile round truck trips per year.

No adverse effects on the existing ambient air quality conditions would occur from implementing the Full IID Water Supply Alternative. Additional emission reduction measures besides those as discussed under Alternative 1 – Proposed Action, would not be required.

3.5.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative

Alternative 5, described in detail in Chapter 2 and shown in Figure 2-6, is the Proposed Action but with Phase 10 reduced, Phase 10P eliminated, and the berm modified correspondingly.

This alternative would reduce the amount of gypsum ore mined by about 5.4 million tons over the life of the mine and reduce its operating life by approximately 2.81 years based on the maximum permitted production rate of 1.92 million tons per year. This reduced mining alternative would not directly or indirectly impact or change daily or annual air emissions as analyzed for the mining operations and waterline options discussed under Alternatives 1, 3, or 4 and evaluated in Table 3.5-3 above.

3.5.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative

Alternative 6, described in Chapter 2 and shown in Figure 2-7, is the Proposed Action except that Phases 4 and 5 would be reconfigured to reduce impacts to waters of the United States, and the berm would be modified correspondingly.

The amount of gypsum ore mined under this alternative would be approximately 11.87 million tons less than under the Proposed Action. At a maximum permitted production of 1.92 million tons per year, Alternative 6 would reduce projected mine life presented in the Proposed Action by 6.18 years. This reduced mining alternative would not directly or indirectly impact or change daily or annual air emissions as estimated for mining operations and various waterline options discussed under Alternatives 1, 3, or 4 and evaluated in Table 3.5-3 above.

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3.5.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative

This alternative would eliminate certain mine phase areas and lower overall gypsum reserves thereby slightly reducing the number of years of operations. This reduced mining alternative would not directly or indirectly impact or change daily or annual air emissions as estimated for mining operations and various waterline options discussed under Alternatives 1, 3, or 4 and evaluated in Table 3.5-3 above.

3.5.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative

Alternative 8, described in Chapter 2 and Figure 2-9, is the Proposed Action but with a reduced mining footprint in Phases 7 and 8 and corresponding modifications to the berm. The volume of ore that would be mined over the life of the quarry would be reduced by approximately 13.04 million tons. At a maximum permitted production of 1.92 million tons per year, this alternative would reduce projected mine life presented in the Proposed Action by 6.79 years.

This alternative would reduce the mining areas and lower overall gypsum reserves thereby reducing the number of years of operations. This reduced mining alternative would not directly or indirectly impact or change daily or annual air emissions as estimated for mining operations and various waterline options discussed under Alternatives 1, 3, or 4 and evaluated in Table 3.5-3 above.

3.5.5 Cumulative Effects

Cumulative effects on air quality would occur if the Proposed Action or its alternatives, combined with the reasonably foreseeable projects identified in Appendix F, would affect the resource even where the Proposed Action or its alternatives alone would not. Section 3.6.4 of the 2006 EIS/EIR discussed cumulative impacts from the proposed project and other development activities in the area affected by the proposed project.

It was determined that air quality emissions were in General Conformity and did not exceed ICAQMD and CEQA thresholds; thus, showing compliance with NAAQS and CAAQS and/or consistency with the SIP plan to meet said standards. As discussed in Section 3.5-4 above, General Conformity and its use of de minimis emission levels to determine conformity ensures that federal activities do not cause or contribute to new violations of NAAQS; do not worsen existing violations of the NAAQS; and do not delay attainment of the NAAQS through a SIP. Since the air quality attainment or non-attainment status are for a region or air basin, compliance in meeting General Conformity as is the case with the proposed project, demonstrates that the

U.S. Gypsum Draft SEIS 3.5-13 July 2019 Chapter 3.5: Air Quality proposed project will not contribute either directly or cumulatively to violations to or delaying attainment of NAAQS in the region.

The ICAQMD and CEQA thresholds are similar to the de minimis thresholds in that they are pre-determined emission levels based on the SIP long-term requirements to meet air quality standards. If a project is less than the threshold it is assumed to be less than significant and would not directly or cumulatively cause, contribute, or worsen violations to the region’s air quality standards.

3.5.5.1 Geographic Scope of the Cumulative Effects Analysis

Projects within the jurisdiction of the ICAPCD including the nonattainment areas for ozone, PM10 and PM2.5 were considered for the cumulative effect’s analysis. These projects are listed in Appendix F.

3.5.5.2 Timeframe of the Cumulative Effects Analysis

The timeframe of the cumulative effects analysis is the operational life of the Proposed Action or its alternatives, estimated at 73 years of Quarry operations and an additional 7 years of Plant operations. Air quality effects during the additional estimated 10 years for facilities decommissioning and final reclamation/revegetation would be minimal compared to operational emissions.

3.5.5.3 Past, Present, and Reasonably Foreseeable Actions

The Proposed Action and its alternatives were in General Conformity and would not result in adverse direct or indirect effects on air quality that would not be mitigated by the measures presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. No cumulative impacts were identified in those documents, nor did the analysis of effects on air quality conducted for this Supplemental EIS identify any changes to the conclusions reported in those earlier documents.

Emissions for the proposed project and its alternatives also do not exceed ICAQMD and CEQA thresholds with implementation of applicable federal, state, and local air quality regulations. The estimated emissions for those pollutants determined to be in nonattainment (NOx, PM10, PM2.5, and VOC in Table 3.5-3) are all less than the estimated emissions from the 2006 Draft EIR/EIS due to increasingly stringent pollution control requirements. The reduced emissions could not cause a cumulative impact since they are less than originally permitted. The proposed project is an historical facility that was considered in the County of Imperial General Plan Update and is consistent with the General Plan which is consistent with the Air Quality Management Plan and SIPs for the Salton Sea Air Basin. The air quality plans and strategies stated in the SIPs for achieving air quality standards in an air basin incorporates existing and future modeled emissions, expected growth in population, traffic, and residential, commercial, industrial, and agricultural land uses. All of this information and air quality modeling is inherently a regional, cumulative assessment utilized to determine the future emissions levels and the control strategies and measures necessary to meet the NAAQS for a region.

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The cumulative projects include numerous solar and geothermal energy facilities, cell towers, power lines, other linear projects, and residential and commercial development mainly within incorporated areas. All projects undergo environmental assessments through the permitting process by the government agency whose jurisdiction the project is located including the BLM, Imperial County, and incorporated cities and must be consistent with their General Plans and if not, must mitigate and/or compensate for increased air emissions. Air quality impacts including cumulative effects are assessed through NEPA for federal projects or projects requiring Federal agency approvals and by the ICAPCD and CEQA for those projects in the County and cities. Where applicable, projects must be in compliance with Federal regulations including General Conformity and must comply with all other applicable ICAPCD and CARB regulations and SIPs with respect to operations, equipment usage, truck fleet emissions and fugitive dust control. The ICAPCD rules and regulations were explicitly developed to limit air pollutants for all types of existing and future development and activities in order to attain and maintain air quality standards. Under these conditions, the cumulative analysis determined that implementing the Proposed Action or its alternatives with its reduced emissions in combination with cumulative projects will not cause adverse direct or indirect effects on air quality. No additional mitigation measures are proposed.

3.5.6 Mitigation Measures

The 2006 Draft EIR/EIS and 2008 Draft EIR/EIS included Mitigation Measures 3.6-1a, 1b, and 1c to address potential impacts on air quality by limiting exhaust emissions from mobile equipment (see Appendix E). These measures remain applicable and no changes to the mitigation measures are proposed.

The mitigation measures and the Abatement Work Plan and Quality Control Plan for Transite pipeline removal would be implemented. Quarry operations would remain in compliance with current Title V Operating Permit requirements and all other applicable ICAPCD and CARB regulations with respect to truck fleet emissions and fugitive dust control. Under these conditions, analyses indicate that implementing the Proposed Action or any of its alternatives would not cause adverse direct or indirect effects on air quality. No additional mitigation measures are proposed.

3.5.7 Residual Effects after Mitigation

The project as regulated by Federal, State and ICAPCD rules and regulations and mitigated as discussed above, meets General Conformity requirements, and would not exceed NAAQS and CAAQS. Adverse, unavoidable impacts on air quality per ICAPCD and CEQA thresholds would not occur. Therefore, no new residual effects would result from the Proposed Action or its alternatives, and no new mitigation measures are proposed.

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3.6 CULTURAL RESOURCES

The effects of the Proposed Action and its alternatives on Cultural Resources were analyzed in Section 3.8 of the 2006 Draft EIR/EIS. This section addresses new information available since publication of the Draft and Final EIR/EIS, any new effects of the Proposed Action and its alternatives on these resources within the affected environment, or any effects that were not analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

3.6.1 Affected Environment

The affected environment of the Proposed Action and its alternatives was described in Chapter 3.8 of the 2006 Draft EIR/EIS. That section of the 2006 Draft EIR/EIS presented the findings of the Archaeological Investigations for the U.S. Gypsum Company Quarry Expansion and Water Pipeline Replacement Project prepared by Pacific Legacy, Inc., 2002. The 2002 Investigation presented the regional prehistory, ethnography, and regional history of the affected environment.

Prior Cultural Resource Studies and Known Cultural Resources

An update to the 2003 Class I archival and records search revealed that 36 prior cultural resource studies have overlapped some portion of the Project APE while five additional studies have been conducted outside but within a 0.25-mile radius of the APE. These studies represented a wide array of cultural resource investigations, including literature reviews, Class III pedestrian inventory surveys, Extended Phase I inventory survey and subsurface testing programs, cultural resource evaluation efforts, and data recovery excavations. The Class III pedestrian inventory conducted by Pacific Legacy in 2002 (Nadolski 2003) was the only previous study that encompassed portions of the Quarry. All other prior cultural resource studies overlapped or were proximate to the Ocotillo to Plant waterline or the Westside Main Canal to Plant waterline including the Draft Class III Cultural Resources Technical Report for the Imperial Valley Solar Project, Imperial County, California prepared for the BLM by URS in 2010 which documented the results of the URS investigation referenced above (Section 3.6.1).

The current archival and records search also revealed that 65 cultural resources have been previously documented within the Project APE. Cultural resources documented within the Project APE include 14 prehistoric archaeological sites, 30 historic period archaeological sites or built environment resources, 11 multi-component resources containing both prehistoric and historic period elements, and 10 isolated finds. The prehistoric resources comprise mostly lithic and ceramic scatters, while many of the historic period resources consist of debris scatters with cans, glass, and metal associated with adjacent road or railway corridors. Fourteen of the historic period resources comprise concrete survey markers, some with debris or signage. Notable historic period built environment resources include Old Highway 80 (CA-IMP-7886H) as well as the Plaster City Quarry, Plaster City Plant (P-13-009303), Plaster City Railroad (CA-IMP- 7739H), Westside Main Canal (CA-IMP-7834H), and San Diego and Arizona Eastern Railroad (CA-IMP-8489H).

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Field Recording Methods and Findings

Field recording efforts in 2018 were limited to the Project APE as defined above (Section 3.6.1). Cultural resources were documented and described in detail as they intersected the APE and noted on records and maps where they paralleled or appeared to extend beyond it. Areas subject to a Class III pedestrian inventory survey were examined using transects of no more than 15 meters, and all newly identified archaeological sites and isolated finds were recorded on Department of Parks and Recreation (DPR) Forms 523. Within the spot-check survey areas, field personnel focused on the locations of known cultural resources to verify the boundaries of those resources with respect to the Project APE and to assess the adequacy of prior survey efforts.

Forty-three previously recorded cultural resources were relocated within the Project APE in 2018 (see Table 3.6-1). These included three prehistoric archaeological sites; 17 historic period archaeological sites or built environment resources; seven multi-component resources with prehistoric and historic period materials, including one that was previously recorded as a prehistoric resource; and two isolated finds. One prehistoric resource (CA-IMP-269) was found to be inaccurately mapped at the SCIC where it intersected with the current Project along the Plant to IID Canal APE. Current survey efforts could not confirm the presence of this site north of the San Diego and Eastern Arizona Railroad. An updated DPR form was completed with the site boundary corrected to accurately reflect its location south of the APE. One historic period site (USG-01), identified during the 2002 inventory survey for this Project, was determined to be a feature of the Plaster City Quarry. As a result, USG-01 has been merged into the larger Quarry site and included on the updated DPR form for the Quarry. Thirteen historic period concrete survey markers associated with Highway 80 were previously recorded as distinct resources; they were noted in 2018 but individual DPR forms were not updated. With the exception of the Plaster City Quarry and Plaster City Railroad (CA-IMP-7739H), all of the previously recorded cultural resources relocated in 2018 were found along the Ocotillo to Plant and/or the Plant to IID Canal waterline alignments. Additionally, two previously recorded isolates, a prehistoric chalcedony flake (P-13-011847) and a USGS survey marker (P-13-013118), were relocated during the 2018 inventory efforts. Isolated cultural resources are not eligible for listing in the NRHP and, therefore, will not be considered further.

Table 3.6-1 Previously Recorded Cultural Resources Relocated within the Project APE Resource Potential Affect to Resource by NRHP Status* Site Type APE Location Designation Project? Resource has potential to be P-13-002355 Ocotillo to adversely affected by removal of Not Evaluated Lithic and Ceramic Scatter Plant existing Ocotillo to Plant Waterline. CA-IMP-2355 Waterline Formal evaluation of eligibility is proposed. Resource would not be affected by Plant to IID P-13-004391 Lithic and Ceramic Scatter; the Project if proposed Plant to IID Not Evaluated Canal Historic Refuse Scatter Canal Waterline is placed within CA-IMP-4391/H Waterline the existing railroad right-of-way. The railroad is still operational and Plaster City P-13-008139 Recommended remains a critical component of US Gypsum Rail Line, Plaster Quarry; Quarry CA-IMP-7739H Not Eligible (URS Quarry Operations. Resource City Railroad Waterline/ 2009) would not be affected by the Powerline Project.

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Resource Potential Affect to Resource by NRHP Status* Site Type APE Location Designation Project? Resource was determined ineligible by BLM for listing to NRHP under the authority of the Recommended Plant to IID P-13-008323 Historic Refuse Scatter and 2014 State Protocol Agreement Not Eligible (Holm Canal Prehistoric Isolate with SHPO following evaluation by CA-IMP-7816/H 2018) Waterline Pacific Legacy (Holm 2018). Resource would not be affected by the Project. Various segments Recommended Eligible (Harris Resource would not be affected by 2000, McKenna the Project. Segments of this P-13-008334 2007, Burkhard et Plant to IID resource within the APE were al. 2007, EPG Westside Main Canal Canal previously determined to be non- CA-IMP-7834H 2007, Mitchell et Waterline contributing elements to the overall al. 2012)/ significance of the resource’s Recommended NRHP eligibility (URS 2009). Not Eligible (URS 2009) Various segments in Imperial County Ocotillo to This Resource would not be Plant affected by the Project. The determined Not Old Highway 80 (Evan Hewes P-13-008418 Waterline; Resource has been previously Eligible (URS Highway, Imperial County S80, Plant to IID determined eligible for listing to the CA-IMP-7886H 2009, ASM SH80, or US State Highway Canal NRHP as a built environment Affiliates 2010, Waterline resource (ASM 2010). AECOM 2011) Various segments Recommended Eligible Ocotillo to Determined eligible by consensus (ASM Affiliates Plant (BLM/SHPO) for the Sunrise P-13-009302 2009, AECOM San Diego and Arizona Waterline; Powerlink Project in 2011. Eastern Railroad Plant to IID CA-IMP-8489H 2011); Two Resource would not be adversely Canal segments affected by the Project. Recommended Waterline Not Eligible (URS 2009) The Plaster City Plant is still Recommended P-13-009303 Plant to IID operational and remains a critical Not Eligible (URS Plaster City Plant Canal component of Quarry Operations. 2009) Waterline Resource would not be affected by the Project. Resource would be affected by the Plant to IID P-13-010066 Project if proposed Plant to IID Not Evaluated Historic Refuse Scatter Canal Canal Waterline is placed within CA-IMP-8969H Waterline the existing railroad right-of-way. Resource would not be affected by Plant to IID P-13-011165 the Project if proposed Plant to IID Not Evaluated Lithic and Ceramic Scatter Canal CA-IMP-10171 Canal Waterline is placed within Waterline the existing railroad right-of-way. P-13-011626/ Resource would not be affected by P-13-012732 Plant to IID Lithic and Ceramic Scatter the Project if proposed Plant to IID Not Evaluated Canal CA-IMP-10538/ Canal Waterline is placed within Historic Refuse Scatter Waterline CA-IMP- the existing railroad right-of-way. 11181/H Resource would not be affected by P-13-011627 Plant to IID Lithic and Ceramic Scatter the Project if proposed Plant to IID Not Evaluated Canal CA-IMP- Canal Waterline is placed within Historic Refuse Scatter Waterline 10539/H the existing railroad right-of-way.

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Resource Potential Affect to Resource by NRHP Status* Site Type APE Location Designation Project? Resource would not be affected by P-13-011628 Plant to IID Prehistoric Habitation Site the Project if proposed Plant to IID Not Evaluated Canal CA-IMP- Canal Waterline is placed within Historic Refuse Scatter Waterline 10540/H the existing railroad right-of-way. Resource would not be affected by Recommended Plant to IID P-13-011629 the Project if proposed Plant to IID Not Eligible Historic Refuse Scatter Canal Canal Waterline is placed within CA-IMP-10541H Waterline (Kay 2009) the existing railroad right-of-way. Resource would not be affected by Recommended Plant to IID P-13-011630 the Project if proposed Plant to IID Not Eligible Historic Refuse Scatter Canal Canal Waterline is placed within CA-IMP-10542H Waterline (Kay 2009) the existing railroad right-of-way. Resource would not be affected by Recommended Plant to IID P-13-011631 Historic Refuse Scatter and the Project if proposed Plant to IID Not Eligible Canal Prehistoric Isolate Canal Waterline is placed within CA-IMP-10543H Waterline (Kay 2009) the existing railroad right-of-way. Resource would not be affected by P-13-011632 Recommended Plant to IID the Project if proposed Plant to IID Not Eligible Historic Refuse Scatter Canal CA-IMP- Canal Waterline is placed within Waterline 010544H (Kay 2009) the existing railroad right-of-way. Resource would not be affected by P-13-011633 Recommended Plant to IID Prehistoric Lithic Scatter the Project if proposed Plant to IID Not Eligible Canal CA-IMP- Canal Waterline is placed within Historic refuse Scatter Waterline 10545/H (Kay 2009) the existing railroad right-of-way. Resource would not be affected by Recommended Plant to IID P-13-011634 the Project if proposed Plant to IID Not Eligible Historic Refuse Scatter Canal Canal Waterline is placed within CA-IMP-10546H Waterline (Kay 2009) the existing railroad right-of-way. Resource would not be affected by P-13-011635 Prehistoric Lithic and Ceramic Plant to IID the Project if proposed Plant to IID Not Evaluated Scatter Canal CA-IMP- Canal Waterline is placed within Waterline 10547/H Historic Refuse Scatter the existing railroad right-of-way. Resource would not be affected by Recommended Plant to IID P-13-011636 Concrete Survey Marker the Project if proposed Plant to IID Not Eligible Canal Associated with Highway 80 Canal Waterline is placed within CA-IMP-10548H (McLean 2009) Waterline the existing railroad right-of-way. Ocotillo to P-13-011790 Resource would not be affected by Not Evaluated Historic Refuse Scatter Plant the Project. CA-IMP-10612H Waterline Resource has potential to be P-13-011792 Ocotillo to impacted by removal of existing Not Evaluated Historic Refuse Scatter Plant Ocotillo to Plant Waterline and CA-IMP-10613H Waterline formal evaluation of eligibility is proposed. Ocotillo to P-13-011801 Resource would not be affected by Not Evaluated Historic Refuse Scatter Plant the Project. CA-IMP-10621H Waterline Resource would be affected by the Plant to IID P-13-013126 Project if proposed Plant to IID Not Evaluated Historic Refuse Scatter Canal Canal Waterline is placed within CA-IMP-11437H Waterline the existing railroad right-of-way. Plaster City Quarry and Historic Plaster City Quarry Plaster City Resource would not be affected by Not Evaluated USG-01 (est. 1902) Quarry the Project. (merged) *NRHP Status indicates the eligibility status of Class I resources for listing in the NRHP according to the Historic Property Data File for Imperial County (California Department of Parks and Recreation 2013), a 2018 supplemental evaluation report (Holm 2018), and confidential cultural resource records on file with the South Coastal Information Center, which are not cited under References.

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In addition to the previously recorded cultural resources that were relocated within the surveyed portions of the Project APE, two prehistoric archaeological sites, 13 prehistoric isolated finds, and nine historic period isolated finds were newly discovered. The two newly identified prehistoric sites (Table 3.6.2) were found during survey of the Plaster City Quarry and Quarry to Well No. 3 waterline/powerline alignment. Neither of these prehistoric archaeological sites has been evaluated for listing in the NRHP. Within the Plaster City Quarry and waterline/powerline APE, a total of 20 isolated resources were identified. These isolate types included prehistoric assayed cobbles or boulders (PLI-2018-ISO-1 through -ISO-2, -ISO-5 through -ISO-9, and -ISO-12), prehistoric ceramics (PLI-2018-ISO-18, and -ISO-20 through -ISO-22), GLO survey markers (PLI-2018-ISO-10 through -ISO-11, and -ISO-14), historic period rock cairns (PLI-2018-ISO-13 and -ISO-15), historic period refuse (PLI-2018-ISO-16 and -ISO-19), and one well head (PLI-2018-ISO-17). The remaining two isolates were located with the Ocotillo to Plant Waterline APE and consisted of a prehistoric projectile point (PLI-2018-ISO-3) and a piece of historic period glass (PLI-2018-ISO-4). As stated previously, isolated cultural resources are not eligible for listing to the NRHP and, therefore, will not be considered further.

Table 3.6-2 Cultural Resources Newly Recorded in 2018 within the Project Area of Potential Effects Resource NRHP Potential for Resource to be Site Type APE Location Designation Status* Affected by Project? Plaster City Resource not likely to be impacted Not Lithic and Ceramic Scatter with Quarry by the Project as it lies on the edge PLI-2018-1 Evaluated Overhang Rock Shelter (jurisdictional of quarry boundaries and away waters) from active mining areas. Plaster City Not Resource would not be affected by PLI-2018-2 Ceramic Scatter Quarry (Well Evaluated the project. No. 3) *NRHP Status indicates the eligibility status of Class III resources for listing in the NRHP.

3.6.2 Methodology

The effects of the Proposed Action and its alternatives on cultural resources were analyzed in Section 3.8 and Appendix E of the 2006 Draft and 2008 Final EIR/EIS. Previous analysis was based on the report Archaeological Investigations for the U.S. Gypsum Company Quarry Expansion and Water Pipeline Replacement Project prepared in 2003 by Pacific Legacy, Inc. (Nadolski 2003). This section of the Draft Supplemental EIS explains the methodology used to analyze the effects of the Proposed Action and its alternatives on cultural resources in the affected environment that are new, have changed, or were not analyzed in those earlier documents.

A Cultural Resources Report (CRR) was prepared by Pacific Legacy, Inc. in June 2018 summarizing the cultural resource investigations completed to date in support of the undertaking. A supplemental CRR (Holm 2018) and an evaluation report (Holson 2018) also were prepared in August 2018 for previously identified cultural resources that have the potential to be affected by the installation of a new waterline as proposed in Alternative 3 and Alternative 4. Changes that have occurred since 2008 were supplemented by the fieldwork and research conducted in 2018 and are summarized herein. Non-confidential versions of the 2018 CCR and supplemental reports are included as Appendix O and are summarized herein.

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The BLM requires that areas not subject to cultural resources inventory survey for over 10 years must be re-examined. Areas that were investigated for this project in 2003 were again inventoried in 2018. Jurisdictional waters subject to Clean Water Act (CWA) 404(b)(1) Permit authorization were also surveyed for cultural resources in support of this Draft Supplemental EIS. The 2003 inventory was updated in 2018 to include surveys of all areas that could be surveyed (e.g. some were not accessible).

The 2018 cultural resources investigations involved the examination of all proposed Project areas on public lands and all potentially affected jurisdictional waters. A total 1,981 acres were inventoried to analyze the Project Area of Potential Effects (APE) for the Proposed Action and its alternatives. Approximately 539 acres are on public lands, 17 acres are on California State lands, and 1,425 acres are on private lands. Areas within the APE that were targeted during the 2018 cultural resources investigation are depicted in Appendix O and described below.

Plaster City Quarry and Water Pipeline/Powerline: The Project APE for the quarry included all proposed mining areas and all jurisdictional waters within the Plaster City Quarry. The APE for the Quarry was the proposed disturbance areas on public lands within the Quarry plus 100 feet, up to the Quarry boundary. The APE for the proposed waterline/powerline between the Quarry and proposed Well No. 3 was 50 feet wide on either side of the proposed pipeline alignment, and the length of the proposed line (approximately 3.45 miles). Approximately 585 acres throughout the APE were determined inaccessible or unsafe to survey due to steep terrain (e.g., 30% slope) or active mining conditions, and were not surveyed.

Ocotillo to Plant Waterline: The Project APE for the existing waterline between Ocotillo and the Plant included a 100-foot wide, 8.7-mile alignment centered on the existing pipeline. URS Corporation (URS) conducted a Class III pedestrian inventory survey in 2008 that included most of the right-of-way for this waterline alignment, therefore this area was subject only to spot- check survey to verify the URS results.

Plant to IID Canal Waterline: The Project APE surveyed for the proposed IID waterline between the Plaster City Plant and the Westside Main Canal included an approximate 5.5-mile long alignment, though the exact route had not been determined prior to the 2018 cultural resources survey. All areas from the north side of the existing highway to the south side of the railroad right–of-way were therefore treated as the potential right-of-way for the waterline (695 feet at the widest point). The Westside Main Canal to Plant waterline was considered to be potentially sited 85 feet south of the railroad centerline and within the railroad right-of-way in accordance with the 2006 Union Pacific Railroad Company and USG longitudinal pipeline encroachment agreement. This waterline alignment was also subsumed by the URS 2008 Class III pedestrian inventory, and so the 2018 survey consisted of spot-checking south of the railroad tracks to verify the URS results.

3.6.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals

Federal laws, policies, and regulations applicable to the Proposed Action and alternatives include the following: the National Historic Preservation Act (NHPA) of 1969, as amended (54 USC 300101 et seq.); Section 106 of the NHPA (54 USC 306108); the National Environmental Policy

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Act (NEPA) of 1969 (42 USC 4321 et seq.); The Archaeological Resources Protection Act (ARPA) of 1979 (16 USC 470aa-470mm); and Executive Order 13007 (Indian Sacred Sites).

Under Section 106 of the NHPA, the BLM is required to take into consideration the effects of the proposed undertaking on historic properties. Per 36 CFR Part 800.16(l)(1) a historic property is defined as any prehistoric or historic district, site, building, structure, or object included in, or eligible for inclusion in, the National Register of Historic Places maintained by the Secretary of the Interior. This term includes artifacts, records, and remains that are related to and located within such properties. The term includes properties of traditional religious and cultural importance to an Indian tribe or Native Hawaiian organization and that meet the National Register criteria.

NRHP criteria are defined under 36 CFR Part 60.4. The analysis of potential effects to historic properties employs the Criteria of Adverse Effect as developed by the ACHP under 36 CFR Part 800. According to 36 CFR Part 800.5(a)(1), an adverse effect is found when an undertaking may alter, directly or indirectly, any of the characteristics of a historic property that qualify the property for inclusion in the NRHP in a manner that would diminish the integrity of the property’s location, design, setting, materials, workmanship, feeling, or association. Examples of adverse effects are outlined under regulation 36 CFR Part 800.5(a)(2).

Other applicable federal policies and guidelines include the Secretary of the Interior's Standards and Guidelines for Archaeology and Historic Preservation listed under FR 190: 44716–44742 as well as policies and procedures outlined in BLM cultural resource program manuals, specifically Manual 8100–The Foundation for Managing Cultural Resources. In 2012, the BLM executed a national Programmatic Agreement (PA) with the ACHP and the National Council of SHPOs. The PA governs the manner in which the BLM meets its responsibilities under the NHPA and encourages BLM State Directors and SHPOs to develop mutually agreed upon BLM-SHPO protocols regulating their relationship and how consultation will take place by establishing streamlined (as opposed to case-by-case) consultations. Since the California BLM administers land in California and Nevada, these protocols were negotiated by the California State Director of the BLM with the California SHPO and Nevada SHPO in 2014. The applicable standards for the Proposed Action and alternatives are found under the Secretary of the Interior's Guidelines for Identification in the 2014 Protocol Agreement. Any updates to these regulations or relevant plans, policies, and management goals are discussed where appropriate.

3.6.4 Direct and Indirect Effects

3.6.4.1 Alternative 1: Proposed Action

This alternative is described in detail in Chapter 2. All proposed phases of the Quarry would be mined, a berm would be constructed along the west side of the Quarry, a new water pipeline and electrical line for the Quarry water supply and the existing water line supplying the Plant would be authorized, and the existing waterline would be removed and replaced.

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A total of five archaeological sites or built environment resources were identified within the direct APE for the Proposed Action. Three of the five resources are the Plaster City Quarry, Plaster City Quarry Railroad (CA-IMP-7739H), and Plaster City Plant (P-13-009303). These are critical components of Quarry operations. Each remains in continuous operation, is well maintained, and will not be adversely affected by any activities of the Proposed Action. The remaining two resources are CA-IMP-2355, a prehistoric lithic and ceramic scatter, and CA-IMP-10613H, a historic refuse scatter. Both are within the direct APE for the removal of the Ocotillo to Plant waterline. CA-IMP-2355/H and IMP-10613H have been determined not eligible for listing in the NRHP and would not be adversely affected by the Project.

The Proposed Action has the potential to affect cultural resources that may exist in areas identified for tamarisk treatment and removal. Driving to and from areas of tamarisk removal is addressed in the Tamarisk Removal Plan (Appendix L-1). Prior to any tamarisk treatment and removal activities on public lands, a cultural resource inventory would be conducted to identify cultural resources in areas identified for vegetation treatment. If it is determined that there may be an impact to historic properties, development of additional cultural mitigation measures will be required prior to any tamarisk removal activity.

Cultural resources that will be avoided by Project activities but have not been evaluated for listing in the NRHP are treated as NRHP-eligible by the BLM (BLM and SHPO 2014:14).

Inadvertent discoveries of currently unknown resources and/or unanticipated damage to resources could occur during construction phases and ground disturbing activities under the Proposed Action. Mitigation Measures 3.6-1 and 3.6-2 (see Section 3.6.6) would therefore be implemented prior to of the start of the Project.

3.6.4.2 Alternative 2: No Action Alternative

This alternative is described in detail in Chapter 2. Under this alternative, none of the activities associated with the Proposed Action or Alternatives 3 through 8 would occur. Operations at the Quarry and Plant would continue as presently permitted and regulated.

The potential effects on cultural resources associated with the Quarry expansion and the waterline/powerline to Well No. 3 would be eliminated, and the effects associated with the Ocotillo to Plant waterline would be reduced. The Yuha Basin ACEC would not be further disturbed, so tamarisk removal in the ACEC would not occur under this project and the potential to affect cultural resources in the ACEC as a result would be eliminated.

Under the No Action Alternative, CA-IMP-2355 and CA-IMP-10613H would not be impacted because there would be no removal or replacement of the existing Ocotillo to Plant waterline.

3.6.4.3 Alternative 3: Partial IID Water Supply Alternative

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Plant. This alternative was analyzed and presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. The potential effects on cultural resources for this alternative would be the same as those associated with the Proposed Action and would also include effects from constructing the IID waterline.

Seventeen previously recorded archaeological sites or built environment resources were identified within the APE for the proposed IID waterline surveyed by Pacific Legacy. All but three sites would be avoided if the Plant to IID Canal waterline were placed north of the San Diego to Arizona Railroad within the existing railroad right-of way: the Westside Main Canal (CA-IMP-7834H), the San Diego and Arizona Eastern Railroad (CA-IMP-8489H), and a historic-period refuse site (CA-IMP-7816). The Westside Main Canal would be connected to the proposed Plant to IID Canal waterline under this alternative, however it would not be affected by Project activities. The San Diego and Arizona Eastern Railroad (CA-IMP-8489H) and the Plaster City Plant (P-13-009003) remain in continuous operation, are well maintained and would not be adversely affected by the activities of this alternative. CA-IMP-7816/H has been determined not eligible for listing in the NRHP and would not be adversely affected by the Project.

3.6.4.4 Alternative 4: Full IID Water Supply Alternative

Alternative 4, described in detail in Chapter 2, is the same as Alternative 3 except that all the water for Plant operations would come from the IID Westside Main Canal and the existing waterline to the Plant would be removed. This alternative was analyzed and presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. The effects described above under the Proposed Action and Alternative 3 would also occur under this alternative. All of the mitigation measures described in Section 3.6.6 would be required if this alternative were implemented.

3.6.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative

Alternative 5, described in detail in Chapter 2 and shown in Figure 2-6, is the same as the Proposed Action but with Phase 10 reduced, Phase 10P eliminated, and the berm modified correspondingly.

Certain areas of the APE within the Quarry were not accessible during pedestrian field surveys for cultural resources, due to steep slopes and/or safety concerns posed by active mining operations. These areas included the active quarry zone and some areas that had been previously quarried; deep gorge-like ravines, draws, or washes; steep-sided and deep slot canyons; steep topography with more than a 30-degree slope; and areas of unstable terrain.

This alternative has the potential to impact cultural resources in the ravine, canyon, and wash areas similar to the Proposed Action, but the magnitude of potential impact would be reduced by eliminating 6.6 acres of losses of waters of the United States. Mitigation Measure 3.6-1 requiring a Construction Monitoring and Inadvertent Discovery Plan would be implemented to ensure the effects are temporary.

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3.6.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative

This alternative has the potential to impact cultural resources in the ravine, canyon, and wash areas similarly as the Proposed Action, but the magnitude of potential impact would be reduced by eliminating 8.62 acres of losses of waters of the United States. Mitigation Measure 3.6-3 requiring a Construction Monitoring and Inadvertent Discovery Plan would be implemented to ensure the effects are temporary.

3.6.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative

This alternative has the potential to impact cultural resources in the ravine, canyon, and wash areas similarly as the Proposed Action, but the magnitude of potential impact would be reduced by eliminating 8.01 acres of losses of waters of the United States. Mitigation Measure 3.6-3 requiring a Construction Monitoring and Inadvertent Discovery Plan would be implemented to ensure the effects are temporary.

3.6.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative

Alternative 8, described in Chapter 2 and Figure 2-9, is the Proposed Action but with a reduced mining footprint in Phases 7 and 8 and corresponding modifications to the berm.

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This alternative has the potential to impact cultural resources in the ravine, canyon, and wash areas similarly as the Proposed Action, but the magnitude of potential impact would be reduced by eliminating 12.07 acres of losses of waters of the United States. Mitigation Measure 3.6-3 requiring a Construction Monitoring and Inadvertent Discovery Plan would be implemented to ensure the effects are temporary.

3.6.5 Cumulative Effects

The cumulative effects analysis in the 2006 Draft EIR/EIS found that new projects or other activities were not proposed at that time within the areas affected by the project that could result in a significant cumulative effect. Pacific Legacy reviewed cumulative projects in 2018 in light of the fact that cumulative effects on cultural resources would occur if the Proposed Action or its alternatives, combined with the reasonably foreseeable projects identified in Appendix F, would affect the resource even where the Proposed Action or its alternatives alone would not.

3.6.5.1 Geographic Scope of the Cumulative Effects Analysis

The area of analysis for cultural resources generally corresponded to the Class I archival and records search area, which was defined as a 0.25-mile radius surrounding the Project APE. This area included the northern Fish Creek Mountains and the lower Salton Trough and, according to the Class I results, included many of the same types of archaeological and historic-period built- environment resources as were found within the APE.

3.6.5.2 Timeframe of the Cumulative Effects Analysis

The timeframe of the cumulative effects analysis is the life of the Proposed Action or alternatives, estimated at up to 73 years of Quarry operations, an additional 7 years of Plant operations, and an additional estimated 10 years for facilities decommissioning and final reclamation/revegetation, for a total of 90 years.

3.6.5.3 Past, Present and Reasonably Foreseeable Actions

Environmental documents for the cumulative scenario projects identified in Appendix F and within the area of analysis were reviewed to determine whether effects on cultural resources would be considered cumulatively adverse. Two projects are in the planning stages and their impacts are unknown. These are the Citizens Imperial Solar LLC on 223 acres to be leased from IID in Imperial County, and the Drew Solar Project to include a General Plan Amendment on 762.8 acres in El Centro. Most of the projects for which data are available are concentrated to the east of the Westside Main Canal near the towns of El Centro and Brawley and are located outside the area of analysis. It was determined that only one project within the area of analysis, the Ocotillo Wind Energy Facility Project, had an adverse effect on resources that are spiritually and culturally significant to local Native American tribes even after the implementation of mitigation measures outlined in a Memorandum of Agreement (BLM 2012:ES-3). Cumulative effects to cultural resources under that project, sited near the Ocotillo to Plant waterline, remained significant.

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The mitigation measures described in Section 3.6.6 will be required under any of the action alternatives to avoid, minimize, and/or mitigate direct effects to cultural resources from construction, operation, and Quarry reclamation. Depending on the outcome of the evaluation of the resources noted in Section 3.6.4.3, specifically CA-IMP-269, the Project is not expected to cumulatively contribute to direct effects on cultural resources within the area of analysis even when the effects of the Ocotillo Wind Energy Facility Project are considered.

Projects reasonably foreseeable and/or undergoing environmental review under NEPA are subject to laws that provide various protections for cultural resources. The severity of impacts on previously unknown cultural resources has been reduced from what has historically occurred by implementing mitigation measures such as construction monitoring, the evaluation of inadvertent discoveries, and the avoidance or mitigation of significant cultural resources.

3.6.6 Mitigation Measures

The 2006 Draft EIR/EIS and 2008 Final EIR/EIS identified mitigation measures to address potential Project impacts on cultural resources. These measures included conducting a cultural resource inventory survey to identify previously unrecorded archaeological and built- environment resources within the Project APE (Mitigation Measure 3.8-1), as well as adhering to protocols regarding the inadvertent discovery of cultural resources (Mitigation Measure 3.8-3).

The cultural resources surveys recommended in the 2006 Draft EIR/EIS as Mitigation Measure 3.8-1 were conducted between April and July 2018 as described above. To the extent prudent and feasible, the BLM intends to avoid impacts on all known cultural resources within the Project APE. Recommendations based on those surveys have prompted the development of new mitigation measures.

Consistent with the BLM’s goal of avoiding impacts on known cultural resources under the Proposed Action and alternatives, the following mitigation measures are proposed in this Supplemental EIS:

Mitigation Measure 3.6-1: Develop and Implement a Plan for Archaeological Monitoring, Post-Review Discovery, and Unanticipated Effects. Avoidance and protection measures for cultural resources within the Project APE will be outlined in a Construction Monitoring and Inadvertent Discovery Plan. This Plan will be prepared and approved prior to the implementation of any of the action alternatives. It will describe worker awareness training, avoidance measures, and monitoring procedures that will be implemented to protect known cultural resources from Project impacts. It will also detail the procedures that will be used to assess, manage, and mitigate potential impacts on inadvertent discoveries during Project implementation.

Mitigation Measure 3.6-2: Develop a Maintenance Notification Agreement for Future Maintenance of the Plaster City Plant Pipeline Right-of-Way Following Construction Completion. A Maintenance Notification Agreement will be outlined prior to the authorization of the pipeline right-of-way grant to ensure continued avoidance of archaeological resources during the life of the grant. This agreement will identify the schedule and data needs that will be submitted by U.S. Gypsum to BLM when

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maintenance is needed on the new Plaster City Plant pipeline. The BLM archaeologist will review this data to determine if and where archaeological monitors are needed during future maintenance activities.

3.6.7 Residual Effects after Mitigation

No significant, residual effects to known cultural resources are anticipated following implementation of the mitigation measures outlined above.

U.S. Gypsum Draft SEIS 3.6-13 July 2019 Chapter 3.7: Special Designations

3.7 SPECIAL DESIGNATIONS

The effects of the Proposed Action and its alternatives relative to Special Designations were analyzed in Section 3.9 Land Use and Planning of the 2006 Draft EIR/EIS. This section addresses new information available since publication of the Draft and Final EIR/EIS and any new effects of the Proposed Action and its alternatives on land use and planning within the affected environment, or any effects not analyzed in the 2006 Draft EIR/EIS or 2008 Final EIR/EIS.

3.7.1 Affected Environment

In 2016 the BLM implemented the Desert Renewable Energy Conservation Plan (DRECP) Land Use Plan Amendment (LUPA) to the California Desert Conservation Area Plan (CDCA). The goal of the DRECP is to protect environmental resources while providing for streamlined siting of renewable energy projects on both public and private land. The area of analysis for this project includes public lands administered by the BLM under the CDCA as amended by the DRECP.

Areas of Critical Concern

The existing waterline supplying the plant and the new waterline proposed under Alternatives 3 and 4 occur within the Yuha Basin Area of Critical Concern (ACEC). ACECs are areas of public lands where special management is required to protect and prevent irreparable damage to important historic, cultural, or scenic values, fish and wildlife resources or other natural systems of processes, or to protect life and safety from natural hazards. The BLM designated the Yuha Basin ACEC for its cultural and wildlife values in 1985 (ACEC Plan No. 64, March 1985) and expanded it in 2016 (CDCA, as amended), and limited permissible surface disturbance to one percent.

California Desert National Conservation Lands

In 2009, Congress directed the BLM to include lands managed for conservation purposes within the CDCA as part of the National Conservation Lands (NCL) system. California Desert NCLs are nationally significant landscapes within the CDCA that meet the criteria for NCLs and have outstanding cultural, ecological, and scientific values. The CDCA, as amended, designated 4.2 million acres as part of the National Conservation Lands of the California Desert (CDNCL), expanding the previous NCL acreage by 2.89 million acres. The CDNCLs incorporate the ACEC site-specific management objectives and use allocations identified in the Special Unit Management Plans (See Appendix B of the DRECP). The existing waterline supplying the plant and the new waterline proposed under Alternatives 3 and 4 occur within areas designated as CDNCL.

Juan de Bautista de Anza National Historic Trail

The Juan de Bautista de Anza National Historic Trail (Anza Trail) was designated by Congress in 1990 through an amendment to the National Trails System Act (16 U.S.C 1241-51). This is a 1,200 mile long trail that commemorates, protects, marks, and interprets the route traveled by

U.S. Gypsum Draft SEIS 3.7-1 July 2019 Chapter 3.7: Special Designations

Anza and the colonists during the years 1775 and 1776 from Sonora, Mexico to settle in Alta California and establish a mission at what is now San Francisco, California. The purpose of the Anza Trail is to preserve a significant part of the history of the American southwest and to provide the means for people to make connections to the story of the Anza expeditions. The National Park Service (NPS) is the overall administrator of the Anza Trail.

The new waterline proposed in Alternatives 3 and 4 would cross the trail location about two miles east of the Plant, parallel to the railroad tracks and Evan Hewes Highway. The physical trail no longer exists at this location.

3.7.2 Methodology

This assessment evaluates the potential effects of the Proposed Action and its alternatives on specially designated land uses in the project vicinity, compared to the conditions as presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS, and specifically related to the federal decisions to be made. The methodology considers the prior NEPA analysis presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS and new information about land use planning in the area. This analysis supplements the prior documentation relevant to any changes in circumstances or requirements for federal action including their conformance with the CDCA, DRECP, LUPA, CMAs and ACEC plans.

3.7.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals

Since the 2006 Draft EIR/EIS and 2008 Final EIR/EIS were published, the BLM implemented the DRECP amendment to the CDCA Plan.

3.7.4 Direct and Indirect Effects

The Proposed Action and its alternatives were analyzed for their impacts on ACECs, CDNCLs, and the Anza Trail.

3.7.4.1 Alternative 1: Proposed Action

ACEC

The existing Plant pipeline is located within the Yuha Basin ACEC. The project would have effects on the ACEC with respect to cultural resources and ground disturbance. The effects of the project on cultural resources in the ACEC are discussed in Chapter 3.5 Cultural Resources.

The Yuha Basin ACEC is located 13 miles west of El Centro. It extends from the U.S./Mexico Border on the south, west to the Jacumba Mountains and east to agricultural lands bordering the

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El Centro urban area. The northern boundary is the Evan Hewes Highway and southern boundary of the Plant property. The Plant property abuts the ACEC. The existing pipeline and the proposed IID pipeline lie within the northern portion of the ACEC, just south of Evan Hewes Highway.

ACECs are subject to surface disturbance caps. The Yuha Basin ACEC currently exceeds the established disturbance cap of 1 percent of its total area. In any ACEC with ground disturbance at or above its designated cap, mitigation of additional disturbance is required as follows:

• Use activity design features to minimize new ground disturbance to the extent practicable. • For the portion of the proposed activity that is located on land within an area previously disturbed by an authorized/approved action that has been terminated, the required disturbance mitigation ratio is 1.5:1. • For the portion of the proposed activity that is located on undisturbed land or land disturbed by unauthorized activities, the required disturbance mitigation ratio is 3:1. • Although the BLM is not required to calculate the ground disturbance cap before approving/authorizing an activity under a Categorical Exclusion, if the BLM knows an area is at or exceeding the cap, the disturbance mitigation requirements would apply to that activity. • In the rare circumstance where the BLM authorizes activities on areas restored (e.g., as disturbance or other forms of mitigation), the required disturbance mitigation ratio requirement is doubled, that is, 3:1 or 6:1, respectively.

The Proposed Action would be required to mitigate at a ratio of 1.5:1, as it lies within lands previously disturbed by an authorized/approved action. The installation of a new water pipeline from the Ocotillo well site to the Plant as identified in the Proposed Action would extend approximately 26,450 feet across public lands within the ACEC, and would disturb 18.21acres. The disturbance mitigation required of the project would be based on a 1.5:1 ratio for the new ground disturbance resulting from project specific actions within the ACEC. For the Proposed Action, 27.32 acres of mitigation would be required.

California Desert National Conservation Lands

The existing waterline to the Plant and the new waterline proposed under Alternatives 3 and 4 intersect with lands designated as CDNCLs. These areas of CDNCLs are coincident with the pipelines in the Yuha Basin ACEC. In addition to the effects on the Yuha Basin ACEC described above, the project would have effects on CDNCLs with respect to cultural resources and the Anza Trail. The project effects on cultural resources are discussed in Chapter 3.6 Cultural Resources.

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3.7.4.2 Alternative 2: No Action Alternative

Under Alternative 2, described in Chapter 2, none of the activities associated with the Proposed Action or its alternatives would occur. Operations at the Quarry and Plant would continue as presently permitted and regulated until the gypsum resource is depleted at the Quarry.

Plant operations could continue after all the material mined at the Quarry ran out, dependent on the availability of secondary sources of gypsum. Continued operations at the Plant would not have any impact on the ACEC, the CDNCLs, or the Anza Trail.

3.7.4.3 Alternative 3: Partial IID Water Supply Alternative

Alternative 3, described in detail in Chapter 2, is the Proposed Action except that the processing water would be partially replaced with irrigation water from the Imperial Irrigation Canal (IID) Westside Main Canal and new settling ponds for treating the IID water would be constructed on USG-owned lands at the Plant. This alternative was analyzed and presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. This alternative would necessitate the installation of a new water pipeline from the IID canal to the Plant.

ACEC: This alternative would have the same effect on the ACEC as the Proposed Action but at a greater magnitude because the new waterline to the Westside Main Canal would occupy an additional portion of the Yuha Basin ACEC not previously analyzed, over a length of about 13,200 feet (about 9 acres). This alternative would have a direct effect on surface disturbance of land within the Yuha Basin ACEC. Because the ACEC already has been previously disturbed beyond its specific cap, mitigation as required by the DRECP would be implemented. The effects of that mitigation are included in this Supplemental EIS. With mitigation, the Partial IID Water Supply Alternative is consistent with the intent of this ACEC.

CDNCLs and Anza Trail: The IID pipeline would create effects on CDNCLs and the Anza Trail not present under the Proposed Action. The IID pipeline would cross the Anza Trail about two miles east of the Plant. As mentioned above, the trail itself does not exist at this location in a physical sense. However, the public could still follow the trail. Short term impacts would include visual and auditory disruption of the experience during construction of the pipeline. After the pipeline is completed, the crossing would be restored to its previous condition and no impacts would remain to interfere with the public’s enjoyment of the trail at this location, or with the values for which this trail was designated a National Historic Trail.

3.7.4.4 Alternative 4: Full IID Water Supply Alternative

ACEC: Alternative 4 would have the same potential effects on the Yuha Basin ACEC as described for Alternative 3, above, but at a smaller magnitude because the existing pipeline

July 2019 3.7-4 U.S. Gypsum Draft SEIS Chapter 3.7: Special Designations between the Plant and Ocotillo would not be replaced. This alternative would have a direct effect on surface disturbance of land within the Yuha Basin ACEC. Because the ACEC already has been previously disturbed beyond its specific cap, mitigation as required by the DRECP would be implemented. The effects of that mitigation are included in this Supplemental EIS.

CDNCLs and the Anza Trail: This alternative would have the same effects on the CDNCLs and the Anza Trail as Alternative 3.

3.7.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative

Alternative 5, described in detail in Chapter 2 and shown in Figure 2-6, is the Proposed Action but with Phase 10 reduced, Phase 10P eliminated, and the berm modified correspondingly.

Alternative 5 reduces the area of disturbance due to mining within a portion of the quarry boundary. It is not within an ACEC, CDNCL, or proximate to the Anza Trail and would not alter affects to these resources addressed in previous alternatives.

3.7.4.6 Alternative 6: Lower Quarry Watershed Modified Mining Footprint “B” Alternative

Alternative 6 reduces the area of disturbance due to mining within a portion of the quarry boundary. It is not within an ACEC, CDNCL, or proximate to the Anza Trail and would not alter affects to these resources addressed in previous alternatives.

3.7.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative

Alternative 7 would reduce the area of disturbance due to mining within a portion of the quarry boundary.

It is not within an ACEC, CDNCL, or proximate to the Anza Trail and would not alter affects to these resources addressed in previous alternatives.

3.7.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative

Alternative 8, described in Chapter 2 and Figure 2-9, is the Proposed Action but with a reduced mining footprint in Phases 7 and 8 and corresponding modifications to the berm.

U.S. Gypsum Draft SEIS 3.7-5 July 2019 Chapter 3.7: Special Designations

Alternative 8 reduces the area of disturbance due to mining within a portion of the quarry boundary. It is not within an ACEC, CDNCL, or proximate to the Anza Trail and would not alter affects to these resources addressed in previous alternatives.

3.7.5 Cumulative Effects

3.7.5.1 Geographic Scope of the Cumulative Effects Analysis

Public lands within Imperial County, the DCREP/LUPA, and the Yuha Basin ACEC, and major projects on private land within the County were considered for determining cumulative project effects on special designations. The cumulative projects considered for this cumulative effects analysis include 54 projects. These projects consist of solar energy farms, cell towers, subdivisions, rights of way, a large water impoundment and one mine. The majority of projects occur within the cities of El Centro and Brawley. Of those on public lands, five involve rights of way for power transmission and one for the creation of a wind energy facility. These projects are proposed within areas managed by the DRECP. One project proposes construction on 12,406 acres of public land.

3.7.5.2 Timeframe of the Cumulative Effects Analysis

The timeframe of the cumulative effects analysis is considered to be the life of the Proposed Action or alternatives, estimated at a maximum of 73 years of Quarry operations, an additional 7 years of Plant operations, and an additional estimated 10 years for facilities decommissioning and final reclamation/revegetation.

3.7.5.3 Past, Present and Reasonably Foreseeable Actions

The Proposed Action and its alternatives are consistent with the DRECP. Application of CMAs will be required per the direction of the plan. The Proposed Action and Alternatives 3 through 8 would contribute to the continued exceedance of the Yuha Basin ACEC’s disturbance cap, adding to the cumulative effects of area disturbance. There is currently one additional proposal for disturbance (a cell tower) within this ACEC.

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The Proposed Action will contribute to the overall conversion of open space lands to occupied land uses. Of the 54,732 acres currently considered in the cumulative impact analysis, the Quarry would add 682 acres of disturbance (1.2%). The Plant and rights of way would not cumulatively contribute to the cumulative impacts associated with Special Designations.

The Proposed Action and alternatives evaluated in this Draft Supplemental EIS could have short term, direct effects on Special Designations related to pipeline construction within rights of way where they coincide with specific land use allocations. These effects would contribute cumulatively to the effects of similar construction projects conducted during the same timeframe or within the same location. At the time of publication, no known construction projects are proposed in the area of the Proposed Action or rights of way. No cumulative impacts were identified in the 2006 Draft EIR/EIS. Further analysis of cumulative effects is not required (BLM NEPA Handbook H-1790-1).

3.7.6 Mitigation Measures

The Proposed Action and Alternatives 3 through 8 would have a direct effect on the Yuha Basin ACEC within the existing and proposed pipelines to the Plant. Any authorized ground disturbance within the ACEC would require the following mitigation measure:

Mitigation Measure 3.7-1: For the portions of the Proposed Action and Alternatives 3 through 8 that result in new ground disturbance within the Yuha Basin ACEC, the required disturbance mitigation ratio is 1.5:1 as it will be located within an area previously disturbed by an authorized/approved action. The total acreage of disturbance mitigation will be based on the actual acreage of new ground disturbance resulting from project construction. Within two months from completion of any pipeline installation USG shall submit a restoration plan delineating the boundary of a restoration area at the required 1.5:1 ratio. The restoration plan shall include a schedule of activities and list all proposed equipment to be used on the project. The BLM shall review and approve the restoration plan prior to USG commencing with restoration activities.

USG proposes to restore lands within the Yuha Basin ACEC through the removal and treatment of tamarisk trees within an area and using methods approved by the BLM. Any deviation from the authorized restoration work will require review and approval of the BLM. The Tamarisk Removal Plan is a Mitigation Measure in Section 3.4 Vegetation and Wildlife and is appended to this document as Appendix L1.

3.7.7 Residual Effects after Mitigation

With implementation of the proposed mitigation measures, the environmental impacts on resources related to the special land use designations would be avoided or substantially reduced. As a result, the proposed project would result in no adverse unavoidable impacts.

U.S. Gypsum Draft SEIS 3.7-7 July 2019 Chapter 3.8: Recreation

3.8 RECREATION

The effects of the Proposed Action and its alternatives on recreation were partially analyzed in Chapter 3.9 Land Use and Planning of the 2006 Draft EIR/EIS. This section addresses new information available since publication of the Draft and Final EIR/EIS, and any new effects of the Proposed Action and its Alternatives on recreational resources in the affected environment, or any effects that were not analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

3.8.1 Affected Environment

Off-road vehicle use is evident within the proposed route of both the Plant and the Quarry waterlines where access is not restricted or controlled by USG fencing or signage. Other recreational activities that may occur within and adjacent to the project area include hiking, hunting, shooting, and camping.

The Quarry, including the private holdings and mill site claims, has no planned recreational designation by any federal, state or local agency. The area to the north and northeast of the Quarry, including the Split Mountain access road, is outside the Superstition Mountain Special Recreation Management Area (SRMA) as identified in the Desert Renewable Energy Conservation Plan (DRECP). Anza-Borrego State Park is located immediately to the north and northwest of the Quarry. Approximately one mile of the proposed new waterline from the Quarry to Well No. 3, immediately north of the Quarry’s northern boundary, is located within the limits of the Anza-Borrego Desert State Park. There are no designated access points or trails into the park along the Split Mountain Road access to the Quarry. The Quarry restricts access through its operations areas to recreational users. Park and BLM-administered land north, northwest, northeast and east of the Quarry is unfenced and unsigned. Access to this area is generally unrestricted. BLM indicates that recreational shooters and OHV riders regularly use this area, principally during the winter months (Oct. through April). Annual visitation for OHV use in this area is estimated by BLM at 178,623 per year; statistics are not maintained for shooters.

Open routes of travel as designated in the Western Colorado (WECO) Desert Routes of Travel Plan occur north of the tram road alignment. The access road adjacent to the tram road is an open designated route of travel (Route 085) from its intersection with Split Mountain Drive north of the Quarry to Evan Hewes Highway and the Plaster City Plant. Route 085 is an unpaved, unmaintained roadway that varies in width with an undefined shoulder. It connects the Superstition Mountains SRMA in the north to the Plaster City SRMA in the south and provides unrestricted access through the U.S. Naval weapons training area separating the two SRMAs. Route 085 is the only road connection between the two use areas. The proposed Quarry pipeline would be located within this roadway. The proposed construction area on public lands would be approximately 10,480 feet long and 30 feet wide.

Recreational vehicle use is evident on the Split Mountain roadway north and east of the Quarry entrance. Recreational vehicle use is also evident in Fish Creek Wash west and east of Split Mountain Road, leading to the Quarry north of the Quarry entrance. The Quarry entrance is gated and signed. The boundaries of the Quarry beyond the gates are not fenced, but the placement of the Quarry within the Fish Creek Wash and the lack of road or trail access limits

U.S. Gypsum Draft SEIS 3.8-1 July 2019 Chapter 3.8: Recreation travel into or out of the area. Public access into the Quarry is restricted. There is no recreational access to the Quarry area, which includes the wash and surrounding mountains. No trails or roads other than those associated with mining exist south of Fish Creek Wash inside the Quarry boundaries.

The portion of the existing Plant pipeline on public lands (BLM case file number CACA- 044014) is approximately 5 miles in length; the Right of Way application for this existing pipeline is for an area of disturbance approximately 30 feet wide for a total of 17.9 acres (see Figure 2-2). The pipeline area is not developed, other than the pipeline itself. It is located between the Evan Hewes Highway and the berm on the alignment of the San Diego and Arizona Railroad track, within the alignment of the abandoned old Evan Hewes Highway. The land use classification of these public lands is National Conservation Lands (NCL) and Areas of Critical Environmental Concern (ACEC). Disturbance associated with off-highway vehicle (OHV) use is evident. The Plaster City SRMA is located on the north side of Evan Hewes Highway and is managed for OHV use. Access to the existing pipeline route outside the Plant property is unrestricted.

Several open routes of travel occur north of Evan Hewes Highway within the Plaster City OHV Open Area. BLM estimates annual visitation of the east and west segments of this SRMA at 5,793 visitors. Additionally, several routes occur south of the San Diego and Arizona Railroad. This area is a designated ACEC (Yuha Basin) by the BLM that is within the Lake Cahuilla Ecoregion. Route 248 is located on public lands south of Evan Hewes Highway and north of the San Diego and Arizona Railroad within the ACEC that may overlap within the proposed Plant pipeline.

Recreational activities, including OHV riding, hunting, hiking, rock and mineral collecting, camping, and sight-seeing, are allowed in the Yuha Basin ACEC. Recreational use of the ACEC is generally light. BLM estimates annual visitation in this area of the Yuha Basin ACEC at 1,645. The California Desert Conservation Area Plan (CDCA) as amended by the DRECP limits surface disturbance in the Yuha Basin to one percent, and that cap has been exceeded. Objectives and management actions to reduce the impact of recreation within the Yuha Basin ACEC include maintaining designated OHV trails per the local Travel Management Plan, Western Colorado Routes of Travel Designation (WECO), prohibiting motorized vehicular recreation events, protecting sensitive species, and promoting non-vehicular events.

3.8.2 Methodology

Recreational uses and wilderness areas in the vicinity of the Quarry and Plant were addressed in the 2006 Draft EIR/EIS in Chapter 3.9 Land Use and Planning and are further updated here. Recreational uses of the public lands and adjacent land were reviewed and changes evaluated.

This analysis supplements the prior documentation relevant to any changes in circumstances or requirements for federal action and evaluates the effects (direct, indirect, and cumulative) of the Proposed Action and its alternatives on recreation in the project area.

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3.8.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals

Desert Renewable Energy Conservation Plan (DRECP) Amendment to the CDCA Plan

The DRECP amends the CDCA and was implemented by the BLM in 2016. The 2006 Draft EIR/EIS and 2008 Final EIR/EIS predated this plan; therefore, the previous NEPA analysis did not address effects of the Proposed Action associated with the CDCA Plan as amended by the DRECP.

Special Recreation Management Areas (SRMA)

Under the CDCA Plan as amended, certain public lands north of the existing waterline to the Plant and the proposed Quarry waterline are designated as Special Recreation Management Areas (SRMAs) and are open OHV use areas. SRMA is a designation placed on BLM- administered lands managed specifically to be high-priority areas for outdoor recreation (BLM Land Use Plan Handbook H-1601-1 2005). The Plant and Quarry are not located within the designated SRMA (January 25, 2018). The two waterlines are within or adjacent to an SRMA.

3.8.4 Direct and Indirect Effects

3.8.4.1 Alternative 1: Proposed Action

Generally, implementing the Proposed Action could minimally degrade recreational experiences and opportunities within and adjacent to the project areas. Direct impacts would occur primarily from temporarily restricted access to public lands during construction for visitors who ride OHVs, hunt, or view wildlife in the proposed pipeline routes. Indirect effects such as equipment noise, dust, and vehicular traffic generated during construction of the pipelines may degrade recreational experiences near the project area. These effects are likely to be minor and short- term.

Construction of the Quarry pipeline would temporarily restrict public use of Route 085 within a 30-foot wide construction footprint from the Quarry to the well site, a distance of approximately 10,480 feet. A detour will be provided during construction to allow continued public access; if it were, the diverted vehicle traffic would be controlled to stay within the presently disturbed roadway. Replacing and maintaining the existing pipeline supplying the Plant would create short-term effects within the proposed pipeline right of way including surface disturbance, equipment placement and construction staging. Access to, and traffic flow on, Route 248 would not be affected.

The project would not affect recreation opportunities within the Yuha Basin ACEC, other than the short-term, construction-related effects of pipeline installation described above.

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3.8.4.2 Alternative 2: No Action Alternative

Under this alternative, none of the activities associated with the Proposed Action or its alternatives would occur. Operations at the Quarry and Plant would continue as presently permitted and regulated. The potential effects as analyzed and described in Sections 3.2 and 4.2 of the 2006 Draft EIR/EIS are unchanged.

The No Action Alternative would not impose any effect on existing recreational use in the area of the Quarry or Plant. As with the Proposed Action, this alternative would not restrict or deny recreational access or interfere with recreational plans or policies outside the boundaries of the existing plant or quarry.

3.8.4.3 Alternative 3: Partial IID Water Supply Alternative

The effects of this alternative would be the same as described above for the Proposed Action in the Quarry area, for the Quarry pipeline, and for the existing pipeline.

The IID pipeline proposed under this alternative would be located within a portion of the Yuha Basin ACEC not previously analyzed under the proposed action. Construction and installation would include short-term, construction-related effects within the pipeline construction area such as surface disturbance, equipment storage and construction staging. These effects would not permanently alter recreational uses that occur in the proposed pipeline alignment, nor restrict or deny authorized recreational uses in the area. Vehicular access within the construction footprint may temporarily be restricted or unavailable during the pipeline construction activities. These effects would be localized and short-term, lasting only for the duration of construction. This alternative would not change the existing conditions of recreational uses of public lands at the Quarry, the Plant, or along the existing pipeline alignment.

3.8.4.4 Alternative 4: Full IID Water Supply Alternative

The effects of this alternative would be the same as described above for the Proposed Action in the Quarry area and the Quarry pipeline. Effects on recreation resources in the area of the IID pipeline would be as described for Alternative 3 above. Effects on recreation in the vicinity of the existing pipeline would be similar in type to those described for the Proposed Action, but

July 2019 3.8-4 U.S. Gypsum Draft SEIS Chapter 3.8: Recreation would be slightly less in duration and in the activities related to staging and installing new pipe because, under this alternative, the existing pipe would not be replaced.

This alternative would not restrict or deny the existing conditions of recreational uses of public lands at the Quarry, the Plant, or along the existing pipeline alignment (Proposed Action).

3.8.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative

Alternative 5, described in detail in Chapter 2 and shown in Figure 2-6, is the Proposed Action but with Phase 10 reduced, Phase 10P eliminated, and the berm modified correspondingly.

The effects of this alternative on recreational resources are the same as described above for the Proposed Action. This alternative would not permanently restrict or deny recreational access or interfere with recreational plans or policies.

3.8.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative

3.8.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative

3.8.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative

Alternative 8, described in Chapter 2 and Figure 2-9, is the Proposed Action but with a reduced mining footprint in Phases 7 and 8 and corresponding modifications to the berm.

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3.8.5 Cumulative Effects

3.8.5.1 Geographic Scope of the Cumulative Effects Analysis

Table F-1 located in Appendix F provides a comprehensive listing of all present and foreseeable projects that could contribute to a cumulative impact on the environment. Projects listed include those located on BLM-administered lands or private lands, and include projects requiring authorizations from the BLM and other local governments, such as Imperial County, and the cities of El Centro, Imperial, and Brawley.

Public lands within Imperial County, the CDCA, and the Yuha Basin ACEC, and major projects on private land within the County were considered for determining cumulative project effects on recreational resources. The cumulative projects considered for this cumulative effects analysis include 54 projects. These projects consist of solar energy farms, cell towers, subdivisions, rights of way, a large water impoundment and one mine. The majority of projects occur within the cities of El Centro and Brawley. Of those projects on public land, five involve rights of way for power transmission and one for the creation of a wind energy facility. Four of these projects are proposed within areas of open space with potential recreational value. One proposes construction on 12,406 acres of public land.

3.8.5.2 Timeframe of the Cumulative Effects Analysis

The timeframe of the cumulative effects analysis is the life of the Proposed Action or alternatives, estimated at a maximum of 73 years of Quarry operations, an additional 7 years of Plant operations, and an additional estimated 10 years for facilities decommissioning and final reclamation/revegetation.

3.8.5.3 Past, Present and Reasonably Foreseeable Actions

The Proposed Action and alternatives evaluated in this Draft Supplemental EIS could have short term, direct effects on recreation related to pipeline construction within designated rights of way where they coincide with areas of recreational use, and indirect effects on recreational users in the vicinity due to the noise, dust, and traffic associated with constructing the pipelines. These effects would contribute cumulatively to the effects of similar construction projects conducted during the same timeframe or within the same location. At the time of publication, no known construction projects are proposed in the area of the Proposed Action or Rights of Way. No cumulative impacts were identified in the 2006 Draft EIR/EIS. Further analysis of cumulative effects is not required (BLM NEPA Handbook H-1790-1).

3.8.6 Mitigation Measures

The 2006 Draft EIR/EIS or 2008 Final EIR/EIS identified no adverse effects to recreational land uses or wilderness areas; and therefore, no mitigation measures were proposed. As discussed above, the Proposed Action and the alternatives evaluated in this Draft Supplemental EIS would not result in adverse effects associated with recreational resources other than short-term impacts from restricted public access, noise, dust, and traffic while the pipelines were constructed.

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The short-term construction related effects could require temporary detour of vehicles, principally on Route 085. In order to minimize disturbance to BLM land outside the existing roadway, construction crews will sign and direct traffic around the construction site during pipeline installation.

Mitigation Measure 3.8-1: To reduce undue degradation of desert lands outside the existing designated Route 085 corridor during quarry water pipeline construction, USG or its contractor will direct and or sign recreational vehicles around the construction zone but within the existing roadway disturbance area.

3.8.7 Residual Effects after Mitigation

With implementation of the proposed mitigation measure, impacts to recreation would be avoided or substantially reduced. As a result, the proposed project would result in no adverse unavoidable impacts.

U.S. Gypsum Draft SEIS 3.8-7 July 2019 Chapter 3.9: Socioeconomics and Environmental Justice

3.9 SOCIOECONOMICS AND ENVIRONMENTAL JUSTICE

The effects of the Proposed Action and its alternatives on social and economic conditions and environmental justice were analyzed in Section 4.3 of the 2006 Draft EIR/EIS. This section addresses new information available since publication of the Draft and Final EIR/EIS, any new effects of the Proposed Action and its alternatives on these resources within the affected environment, or any effects that were not analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

3.9.1 Affected Environment

The purpose of a socioeconomic and environmental justice evaluation is to present demographic and economic data such as population size, employment by industry sector, information about minority and low-income populations, and other information relevant to potential impacts of a proposed action and alternatives.

The 2006 Draft EIR/EIS presented population, demographic characteristics and income data associated with minority groups and low-income groups in the area of the project. The document evaluated the social and economic effects of the project in the Ocotillo/Quarry region and the El Centro region of Imperial County. These regions were determined based on the location of the project components and the direct effects of the project that were expected to occur in the city of El Centro and in several communities of the Ocotillo/Coyote Wells groundwater basin area in the southwestern part of Imperial County.

3.9.2 Methodology

The major region of influence included in this environmental justice analysis is the County of Imperial. Throughout this section it may also be referred to as the general population or the affected area.

According to NEPA Guidelines, a minority population should be identified where either the minority population exceeds 50 percent, or the minority population percentage is meaningfully greater than that of the general population. Because Hispanic or Latino population groups are greater than 70 percent throughout the County of Imperial, this analysis focuses on the second option, whether or not a minority population group is meaningfully greater than that of the general population (County of Imperial). The data used in the 2006 Draft EIR/EIS was reviewed and updated herein to provide a comparison of the 2000 and 2010 Census data.

County Conditions, Employment and Unemployment

Imperial County, located within the Colorado Desert, is the ninth largest county in area in California. It ranks 30th of 58 California counties in terms of population with 180,000 people, most of whom reside in the city of El Centro (population 65,822). The county consists of seven cities and eight unincorporated communities, including the Ocotillo Census-Designated Place (CDP). Imperial County, established in 1907, was the last county to be established in the State of California. This county is rich in agricultural heritage. Imperial County is responsible for the

U.S. Gypsum Draft SEIS 3.9-1 July 2019 Chapter 3.9: Socioeconomics and Environmental Justice production of half the nation’s winter-harvested vegetables and home to numerous renewable energy resources including geothermal, wind, and solar. The Imperial Sand Dunes Recreation Area acts as a point of interest for outdoor recreational activities along with the Salton Sea National Wildlife Refuge.

Employment within the County occurs within 13 major industry sectors as shown on Table 3.9-1 below. The sector with the largest employment base is “Education, Health Care, and Social Assistance”, followed by “Retail Trade”. Employees of USG are included in the category of “Agriculture, Forestry, Fishing & Hunting, Mining”.

Table 3.9-1 Employment by Industry Sector Imperial El Centro Ocotillo Industry County Region CDP Civilian Employees 2016 58,456 22,099 38 Ag, forestry, fishing & hunting, mining 5,464 1,661 0 Construction 2,724 1,094 13 Manufacturing 2,626 845 6 Wholesale trade 1,562 474 0 Retail trade 8,492 3,447 0 Transport, warehousing, and utilities 3,926 1,577 9 Information 534 296 0 Finance and ins, and real estate 2,003 935 0 Prof, mgmt, admin, & waste mgmt 3,786 1,555 10 Edu, health care, & social assistance 14,673 5,953 0 Arts, entertain, rec, accomod, & food 4,381 1,442 0 Other services, except public admin 2,384 926 0 Public administration 5,901 2,697 0 Percent of Area’s Total Civilian Employees Ag, forestry, fishing & hunting, mining 9.3% 7.5% 0.0% Construction 4.7% 5.0% 34.2% Manufacturing 4.5% 3.8% 15.8% Wholesale trade 2.7% 2.1% 0.0% Retail trade 14.5% 15.6% 0.0% Transport, warehousing, and utilities 6.7% 7.1% 23.7% Information 0.9% 1.3% 0.0% Finance and ins, and real estate 3.4% 4.2% 0.0% Prof, mgmt, admin, & waste mgmt 6.5% 7.0% 26.3% Edu, health care, & social assistance 25.1% 27.0% 0.0% Arts, entertain, rec, accomod, & food 7.5% 6.5% 0.0% Other services, except public admin 4.1% 4.2% 0.0% Public administration 10.1% 12.2% 0.0% Source: U.S. Census Bureau. “American Community Survey 5-year estimates,” 2016

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As indicated in Table 3.9-1, the Agriculture, Forestry, Fishing & Hunting, and Mining sector is the fourth largest industry in Imperial County and in the El Centro region, at 9.3% and 7.5% respectively. USG’s gypsum mining operations are included in this category. The manufacturing industry is only responsible for a small sector of employment both in the county and in the El Centro region (4.5% and 3.8%, respectively) and includes the manufacturing of wallboard that takes place at the Plant.

The Quarry and Plant are located in Census Tract 123.01 in Imperial County. Census Tract 123.01 encompasses approximately 916 square miles of western Imperial County. Along with the Ocotillo Census-Designated Place (CDP), it forms the Ocotillo/Quarry portion of the socioeconomic study area. The other portion of the study area, the El Centro region, is expected to serve as a central point of commerce and labor for this project and is composed of 10 Census Tracts: 112.01, 112.02, 113, 114, 115, 116, 117, 118.01, 118.02, and 118.03.

Current employment of USG at the Plaster City facility (Plant and Quarry) is approximately 400; the total employment decreased by approximately 16 percent since the 2006 Draft EIR/EIS was prepared due to the 2008 economic recession. USG’s Human Resources Department maintains employee Self-Identification Forms, which indicate that 92 percent of employees self-identify as part of a minority group.

Because such a high proportion of employees, as well as the general population, are members of a minority group, environmental justice issues are an important consideration. According to Environmental Justice: Guidance under the National Environmental Policy Act (CEQ December 1997), minority individuals are defined as members of the following groups: American Indian or Alaskan Native; Asian; Native Hawaiian or other Pacific Islander; Black; other race or combination of two or more races; or Hispanic/Latino ethnicity (of any race). The second criterion for identifying environmental justice populations is low-income status. Low-income population groups are identified by determining the percentage of individuals in the County whose incomes are below the poverty level and comparing it with the percentage of households below poverty level in the Census tracts. If the percentage of low-income households in the tracts exceeded the County average, that tract is further analyzed for potential environmental justice impacts.

Table 3.9-2 show the breakdown of low-income and minority populations for the two portions of the socioeconomic study area, with statewide and Imperial County data for comparison. Data are 2017 estimates from the Bureau of the Census American Factfinder, accessed 5-1-2019.

Therefore, both parts of the socioeconomic study area are considered to be environmental justice populations because they contain greater than 50% minority populations.

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Table 3.9-2 Minority and Low-Income Populations % Individuals Environmental Below Poverty Justice population Area: Population % Minority1 Level (and basis) California 38,982,847 62.1% 15.1 Imperial County 182,830 88.7% 21% El Centro Y Region Tract 112.01 6,761 85% 8.2% Y (minority) Tract 112.02 5,637 95% 43% Y (both) Tract 113 12,071 94% 21% Y (both) Tract 114 4,568 97% 38% Y (both) Tract 115 6,076 95% 45% Y (both) Tract 116 6,159 93% 22% Y (both) Tract 117 5,184 89% 15% Y (minority) Tract 118.01 3,968 76% 3% Y (minority) Tract 118.02 5,509 83% 16% Y (minority) Tract 118.03 6,373 90% 8% Y (minority) Ocotillo/Quarry Y Region Tract 123.01 4,956 85% 7% Y (minority) Ocotillo CDP 266 24% 46%2 Y (income)

3.9.3 Changes in Applicable Regulations, Plans, and Policies/Management Goals

Social and economic conditions as a subject of environmental review are not subject to direct regulation or management; however, these conditions have the potential to be affected by actions and there are several applicable laws to be considered by federal agencies. Social and economic conditions are commonly recognized and addressed as a concern in a wide variety of federal, State, and local planning and management processes, including the BLM land use management planning process. Oher applicable socioeconomic laws, ordinances, and regulations that apply are shown in Table 3.9-3.

No changes to any of the above laws, ordinances, regulations, or standards have been adopted since 2008.

1 Minority status was determined by using the estimate of the percentage of individuals who are “White alone, not Hispanic/Latino” and subtracting from 100 percent.

2 Because of the CDP’s small population size, this estimate has quite a large associated confidence interval, meaning that the actual percentage has a chance of being much higher or lower.

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Table 3.9-3 Applicable Laws, Ordinances, Regulations, and Standards Applicable Law Description Federal Executive Order 12898 The order requires the EPA and all other Federal agencies (as well as State agencies receiving Federal funds) to develop strategies to address this issue. The agencies are required to identify and address any disproportionately high and adverse human health or environmental effects of their programs, policies, and activities on minority and/or low-income populations. Civil Rights Act of 1964, Public Law 88 Title VI of the Civil Rights Act prohibits discrimination on the 352, 78 Stat. basis of race, color, or national programs in all programs or 241 (Codified as amended in several activities receiving Federal financial assistance. sections of 42 USC) State California law defines environmental justice as “the fair treatment Government Code Section 65040.12 and of people of all races, cultures and income with respect to the PRC Section 72000 development, adoption, implementation, and enforcement of environmental laws, regulations, and policies.” Table Key: AB = Assembly Bill; AMT = alternative minimum tax; EPA = United States Environmental Protection Agency; PRC = Public Resources Code; SB = Senate Bill; USC = United States Code; stats = Statutes enacted by law.

3.9.4 Direct and Indirect Effects

3.9.4.1 Alternative 1: Proposed Action

The minority and low-income groups located within the El Centro Region and Tract 123.01 may be disproportionately affected by the impacts of the Proposed Action or its alternatives according to NEPA standards. Those impacts are expected to result in slightly greater local employment opportunities and consumer spending, resulting in an overall net beneficial effect.

The Proposed Action would result in the development of additional gypsum reserves at the Quarry. The hours of operation at the Plant and Quarry would not be altered, and the approved rate of annual production of gypsum at the Quarry would not change. No additional employees at the Quarry are anticipated under current market conditions. In addition, no new access roads or extensions of service would be required at either the Plant or the Quarry. Consequently, the Quarry operations are not expected to increase either the local population or the demand for housing and associated facilities. The additional gypsum reserves in the expansion areas would result in a longer mine life and a correspondingly longer time period over which the community would benefit from the mine’s contribution to the local economy.

The increased board line production capabilities at the Plant would occur as quarrying activity is expanded. USG estimates that employment at the Plant could be increased by up to 140 jobs over the life of the project. That increase represents 0.01% of the total El Centro/Ocotillo regional

U.S. Gypsum Draft SEIS 3.9-5 July 2019 Chapter 3.9: Socioeconomics and Environmental Justice employment base from which the additional employees are expected to be drawn. Housing is available in the El Centro market area to accommodate this increase. The addition of 140 employees would create small secondary effects on the local economy such as increased commerce and consumer spending in local communities, proportional to the increase in the local employment market. Most of the economic effects are expected to occur within the El Centro Region because of its proximity to the Proposed Action.

3.9.4.2 Alternative 2: No Action Alternative

Under Alternative 2, described in detail in Chapter 2, none of the activities associated with the Proposed Action or its action alternatives would occur. Operations at the Quarry and Plant would continue as presently permitted and regulated. The potential effects as analyzed and described in Sections 3.2 and 4.2 of the 2006 Draft EIR/EIS are unchanged.

USG anticipates that approximately 2 million tons of usable rock material remains in its present operating boundaries. At the currently permitted maximum operating rate, this resource would be depleted in about one year. Under the No Action Alternative, quarry operations would cease when the ore within the current mine boundaries is depleted. The Quarry would be reclaimed. There would be no further employment at the Quarry after the period of reclamation, and there would be no further employment at the Plant once the supply of mined ore were processed. The No Action Alternative would result in the loss of 400 jobs in the area, reducing future employment opportunities for the current USG employees at the Quarry and Plant and for the working population in the area at large, resulting in a negative impact on the minority population.

3.9.4.3 Alternative 3: Partial IID Water Supply Alternative

The effects of this alternative on environmental justice would be the same as the Proposed Action with respect to the Quarry operations and the existing waterline. The new water supply pipeline between the canal and the Plant would be located within an alignment either north of the railroad or on the north or south side of Evan Hewes Highway. The pipeline alignment would not pass through any developed communities or interfere with existing infrastructure. The demand on the water wells in Ocotillo would be reduced.

Alternative 3 would not alter the demographics within the affected region. This alternative would not have any adverse effect on low-income or minority populations, as there would be no permanent change in employment. There would be a slight increase in short-term employment opportunities related to the construction of the pipeline to the canal. Employment levels at the Plant or Quarry would not change over those projected for the Proposed Action. A reduction in

July 2019 3.9-6 U.S. Gypsum Draft SEIS Chapter 3.9: Socioeconomics and Environmental Justice use of groundwater from the water wells in Ocotillo would not have a direct or indirect effect on low-income or minority populations based on demographics of the area.

3.9.4.4 Alternative 4: Full IID Water Supply Alternative

The economic and social justice impacts of this alternative would be the same as for Alternative 3 with respect to the Quarry operations and constructing the IID waterline. An additional impact is that the Plant would stop using any water from the wells at Ocotillo to process gypsum. This effect represents a positive impact to the communities that depend on wells for their domestic water supply. It represents a negative economic impact to USG because of the need to construct another pipeline. USG would also require a more intensive water treatment system and larger water storage facilities than for Alternative 3. This alternative would provide the same short-term employment opportunities during construction as Alternative 3.

Alternative 4 would not alter the demographics within the affected region. This alternative would not have any adverse effect on employment of low-income or minority populations as there would be no permanent change in employment other than the short-term effect of construction labor to install the IID pipeline and remove the existing one. Employment levels at the Plant or Quarry would not change over those projected under the Proposed Action. A reduction in use of groundwater from the water wells in Ocotillo would not have a direct or indirect effect on low- income or minority populations based on demographics of the area.

3.9.4.5 Alternative 5: Lower Quarry Watershed Reduced Mining Footprint “A” Alternative

Alternative 5, described in detail in Chapter 2 and shown in Figure 2-6, is the Proposed Action but with Phase 10 reduced, Phase 10P eliminated, and the berm modified correspondingly. Under this alternative, approximately 5.4 million tons less gypsum ore would be mined than under the Proposed Action. At a maximum permitted production of 1.92 million tons per year, this alternative would reduce the projected mine life presented in the Proposed Action by 2.81 years.

The reduction in ore that would be mined under this alternative would reduce the life of the mine from 73 years for the Proposed Action to 70 years for this alternative. The actual employment numbers by year cannot be accurately predicted so far into the future, nor can it be assumed that the demographic composition of the area would be the same in 70 years as it is today. At today’s mine production rates, the reduction in mining would translate into the loss of 400 jobs beginning approximately 70 years from now. Likewise, the direct effect on housing 70 years into the future is difficult to project, but effects are anticipated to be negligible. Secondary effects may include a reduction in commerce and consumer spending in local communities, proportional to the decrease in local employment due to the mine closure.

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3.9.4.6 Alternative 6: Lower Quarry Watershed Reduced Mining Footprint “B” Alternative

Alternative 6, described in Chapter 2 and shown in Figure 2-7, is the Proposed Action except that Phases 4 and 5 would be reconfigured to reduce losses of waters of the United States, and the berm would be modified correspondingly. The amount of gypsum ore mined under this alternative would be approximately 11.87 million tons less than under the Proposed Action. At a maximum permitted production of 1.92 million tons per year, Alternative 6 would reduce projected mine life presented in the Proposed Action by 6.18 years.

The impacts of this alternative on socioeconomics and environmental justice would be the same as for Alternative 5, except that the reduction in the life of the mine would be approximately six years instead of almost three years.

3.9.4.7 Alternative 7: Middle Quarry Watershed Reduced Mining Footprint Alternative

A reduction of one year in the projected duration of the mine operation is insignificant compared with the Proposed Action mine life of 70 years. Further, the uncertainty in predicting employment rates at the mine and the demographic composition of the area over 70 years is proportionally large compared with the one-year change in the life of the mine. The socioeconomic and environmental justice impacts of this alternative are therefore considered to be virtually the same as those of the Proposed Action.

3.9.4.8 Alternative 8: Upper Quarry Watershed Reduced Mining Footprint Alternative

Alternative 8, described in Chapter 2 and Figure 2-9, is the Proposed Action but with a reduced mining footprint in Phases 7 and 8 and corresponding modifications to the berm. The overall mining footprint would be reduced by 34 acres, thereby decreasing potential mining beneath the valley alluvium where gypsum ore has been determined to be most abundant. The volume of ore that would be mined over the life of the quarry would be reduced by approximately 13.04 million tons. At a maximum permitted production of 1.92 million tons per year, this alternative would reduce projected mine life presented in the Proposed Action by 6.79 years.

The effect of this alternative on the mine life is similar to that of Alternative 6; therefore, the impacts of this alternative on socioeconomics and environmental justice are considered to be the same as those discussed above for Alternative 6.

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3.9.5 Cumulative Effects

3.9.5.1 Geographic Scope of the Cumulative Effects Analysis

The geographic area of cumulative projects for effects for socioeconomics and environmental justice would be Imperial County, a CDP. Cumulative projects located within Imperial County are listed and mapped in Appendix F.

3.9.5.2 Timeframe of the Cumulative Effects Analysis

The timeframe of the cumulative effects analysis is considered the longest life of the Proposed Action or the alternatives, estimated at 73 years of Quarry operations, an additional 7 years of Plant operations, and an additional estimated 10 years for facilities decommissioning and final reclamation/revegetation.

3.9.5.3 Past, Present and Reasonably Foreseeable Actions

The Proposed Action would not have adverse direct or indirect effects on minority or low- income populations. The Proposed Action would create approximately 140 additional jobs (at the Plant, none at the Quarry), representing approximately 0.01 percent of the regional employment, which are expected to be filled by the local labor pool. The No Action Alternative would have slight negative direct and indirect effects on the minority population through the loss of employment and negative socioeconomic effects that would occur due to the eventual reclamation of the Quarry and closure of the Plant. The non-energy projects included within the cumulative effects analysis were not evaluated for a specific duration of time. For purposes of the energy projects analysis, the anticipated life was 30 years followed by site decommissioning. The total employment per facility was estimated at 20 – 27 and therefore the 0.01 percent change in employment related to the Proposed Action would not change cumulatively.

Employment projections related to present and reasonably foreseeable actions are included in County and city General Plans to ensure public infrastructure and public services are made available to meet projected growth. Analyses of other actions that are non-federal are conducted in light of the applicable General Plans to determine impacts. Most of the cumulative projects considered would not create major long-term employment needs. Solar projects require a minimal number of employees (e.g. < 25) following construction. Cumulatively, the projects along with the Proposed Action and Alternatives would not have adverse direct or indirect effects on minority or low-income populations.

3.9.6 Mitigation Measures

The 2006 Draft EIR/EIS and 2008 Final EIR/EIS did not identify significant adverse effects on environmental justice, and no mitigation measures proposed. The Proposed Action and its action alternatives presented in this Supplemental EIS would not have adverse effects, directly or indirectly, on the region’s demographics or socioeconomic conditions; and therefore, no mitigation measures are proposed in this document. The No Action Alternative would reduce existing as well as future projected employment opportunity for the region’s minority population

U.S. Gypsum Draft SEIS 3.9-9 July 2019 Chapter 3.9: Socioeconomics and Environmental Justice because quarrying would cease in approximately one year when all the permitted gypsum reserves have been mined and processed. Once reclamation of the mine was completed, there would be no new employment generated in association with this project. Although employment would be reduced with decommissioning of the project, it is also expected that the trend in population growth would continue and the reduction would affect a smaller percentage of the total labor force. It is also expected that other facilities within the same employment sector (refer to Table 3.9-1) would have experienced an increase in employment. No mitigation measures are recommended.

3.9.7 Residual Effects after Mitigation

There would be no adverse, unavoidable impacts on socioeconomic or environmental justice; no mitigation measures are proposed; and therefore, no residual effects would occur.

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3.10 OTHER RESOURCES SUPPLEMENTAL ANALYSIS

The effects of the Proposed Action and its alternatives on resources other than those described in the chapter sections above were analyzed in the 2006 Draft EIR/EIS. These resources and the sections in which they were presented are:

 Visual Resources (Section 3.7, Appendix F)  Hazards and Hazardous Materials (Section 3.10)  Traffic and Circulation (Section 3.11)  Acoustics/Noise (Section 3.12)  Public Health and Safety (Section 3.13)

This Draft Supplemental EIS describes new circumstances or information about environmental concerns related to the federal aspects of the Proposed Action and addresses new alternatives that are outside of the range of alternatives analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

3.10.1 Affected Environment

As described in the 2006 Draft EIR/EIS and the current County of Imperial General Plan (2015), the western portion of Imperial County is a sparsely populated area characterized by public lands consisting of state and federal wilderness areas, military bombing ranges, off-highway vehicle recreation areas, and private lands used for agriculture. Rural residential uses are limited to areas south and west of Plaster City and along Split Mountain Road north of the Quarry. Both the Plant and Quarry are relatively isolated from populated areas in the County. The Quarry operations excavate and process gypsum ore using heavy earthmoving equipment, crushing and other equipment, conveyors, and storage equipment. This equipment uses petroleum products for fuel and lubrication. Such substances include diesel fuel, gasoline, cleaning solvents, and adhesives. USG also uses explosives to blast minerals from the ore body on average three times per month. The explosives are stored in portable magazines. The crusher is used on average twenty times per month.

BLM classifies the Quarry area as Visual Resource Inventory Class IV, the objective of which is to provide for management activities that require major modifications of the existing character of the landscape. The level of change to the character of the landscape can be high.

The transportation system within the study area is defined as the local roadway system and an existing rail system for movement of goods and people. Traffic accesses the Quarry via Evan Hewes Highway. Evan Hewes Highway is parallel to Interstate 8 and connects Plaster City to El Centro, California. Evan Hewes Highway connects to Interstate 8 via Imperial Highway, Dunaway Road and Drew Road. The Quarry is accessed from State Highway 78 to Split Mountain Road. The Imperial County General Plan Circulation and Scenic Highways Element (2008) descriptions of these roadways are as follows:

• Evan Hewes Highway, through the City of El Centro, connects to Adams Street and is constructed with two travel lanes in each direction. Most portions of this facility are

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constructed with one travel lane in each direction. West of the City of Holtville, the road corridor becomes SR-115 for approximately one mile. • Interstate 8 is a four‐lane divided conventional freeway which connects San Diego, California to Yuma Arizona. The interchanges providing access to the Plant within the Project area are located at Imperial Highway, Dunaway Road and Drew Road. • Dunaway Road is a two‐lane undivided rural highway which connects Evan Hewes Highway to Interstate 8. The existing highway structural section is in fair condition. • Drew Road is a two‐lane undivided rural highway which connect Evan Hewes Highway near Seeley to Interstate 8. The existing highway structural section is in fair condition. • Route 78 is a two-lane conventional highway throughout its alignment, although some portions have been upgraded to a four-lane expressway and four-lane conventional highway as a result of recent improvement projects. • Split Mountain Road is a two-lane rural highway which begins at the Quarry and connects directly to Route 78.

The Project components are located in rural, sparsely populated areas with no sensitive receptors nearby. In the vicinity of the Plant site, there are BLM off highway vehicle areas where the public can drive off‐road vehicles. The Plant area and surrounding industrially zoned properties are not considered to be noise sensitive. In the vicinity of the Quarry, the State Park and federal Wilderness Areas are noise sensitive for hikers traversing the remote areas of the park or wilderness area. However, there are no designated trails or camping areas in the Wilderness Area or State Park near the Quarry.

The region is sparsely populated and there are no residents in the immediate vicinity of the Plant site. Activities at the Plant consist of rock unloading and storage areas, milling and processing areas, material warehouses, two wallboard production lines, truck and rail loading areas, and administration and other facilities. The process of wallboard manufacturing involves activities that could generate potential health and safety impacts on Plant employees but not to the general public due to lack of a permanent population in the vicinity. The Quarry consists of gypsum extracting and hauling vehicles and equipment, crushing and other equipment, conveyors, storage equipment, haul roads, administration and other facilities, and an access road. Like the Plant, activities at the Quarry involve activities that could generate potential health and safety impacts on Plant employees, but not to the general public due to lack of a permanent population in the vicinity.

3.10.2 Methodology

The applicable regulations, plans, policies, and management goals related to each of the resources considered in this section are presented in Section 3.2.3. These were reviewed in June 2018 to determine whether any have changed since the 2006 Draft EIR/EIS and 2008 Final EIR/EIS were published.

Alternatives analyzed for this Supplemental EIS were compared with the alternatives in the prior environmental documents to identify which ones were adequately analyzed and described in the prior documents, and which are new or may require supplemental information.

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The BLM Visual Resource Management system was employed in the 2006 Draft EIR/EIS to assess the visual effects of the Proposed Action and its alternatives (as defined in 2006).

3.10.3 Direct and Indirect Effects

The previous analysis of the other resource areas as listed above was determined to be complete with respect to Alternatives 1 through 4. No changes have occurred since the 2006 Draft EIR/EIS and 2008 Final EIR/EIS that would warrant new analyses of effects on the resources discussed in this chapter, or which would change the outcome of the previous analyses.

Alternatives 5 through 8: Alternatives 5 through 8 were developed after the publication of the previous environmental documents. These four alternatives propose modifications of the mining phases that would reduce the amount of gypsum to be mined. They were developed primarily to reduce the impacts of the mining operations on waters of the United States. The mining methods, reclamation techniques, and revegetation practices would remain the same as described in the Proposed Action. The direct and indirect effects on all of the environmental resources addressed in this section would be substantively the same as those of the Proposed Action as analyzed in the 2006 Draft EIR/EIS and the 2008 Final EIR/EIS. They would occur over a shorter duration and to a lesser extent compared with the Proposed Action because of the reduced mining phases. No new analysis of the effects of these alternatives on the resources addressed in this section is warranted.

Visual/Aesthetics: The analyses of effects on visual/aesthetic resources conducted for the 2006 Draft EIR/EIS indicated that the effects of the Proposed Action would not be adverse. Mitigation Measure 3.7-1 was proposed to reduce visual impacts associated with the Inert Material Storage Area (IMSA) at the Plant, where damaged or out-of-specification gypsum products are moved to from the production facility. This site is located entirely on USG property.

Because the Quarry is surrounded by mountains on three sides, public views are limited to views from Split Mountain Road and the Fish Creek Wash on the north side of the Quarry. The Quarry itself is not accessible to the general public. The Quarry expansion would be noticeable only to those passers-by who are using the wilderness area immediately north of the Quarry. Because the Quarry is in lands classified as Visual Class IV, increasing areas of mining at the Quarry will not adversely affect the visual resources in the vicinity.

Hazards and Hazardous Materials: The storage and use of Ammonium Nitrate Fuel Oil (ANFO) and high explosives to blast the development areas in the mine was determined in the 2006 Draft EIR/ EIS and 2008 Final EIR/EIS to be potentially hazardous. This effect would be mitigated by USG’s compliance with the requirements of 27 CFR Part 55, and with any applicable local requirements that are more stringent than the federal regulations. Mitigation Measure 3.10-1, presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS and in this document, Appendix E would apply to this project. With implementation of these measures, there would be no new adverse direct or indirect effects associated with the use of ANFO under the Proposed Action or Alternatives 2 through 4. Alternatives 5 – 8 all represent reductions in the area and amount of gypsum to be mined. The use of ANFO would be correspondingly lower for these alternatives

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than for the Proposed Action or for Alternatives 3 and 4, and the potential impacts due to the use of ANFO would be less. No additional mitigation measures are proposed.

Traffic and Circulation: No adverse effects associated with traffic and circulation along Evan Hewes Highway, Interstate 8, Dunaway Road, or Drew Road were identified in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS, and no mitigation measures were proposed. No new adverse effects associated with the Proposed Action or the alternatives analyzed in the 2006 Draft and 2008 Final EIR/EIS were identified. Alternatives 5 through 8 all propose reduced areas and duration of mining operations compared with the Proposed Action. The effects of these alternatives on traffic and circulation are expected to be the same as the Proposed Action, albeit of slightly shorter duration because the working life of the mine would be slightly reduced under Alternatives 5 through 8. No additional effects to traffic and circulation would occur.

Acoustics/Noise: Blasting activities occur at the Quarry an average of three times per month, and the crusher is used approximately 20 times per month. There were no adverse or significant impacts on human receptors from noise identified in the 2006 Draft EIR/EIS or 2008 Final EIR/EIS and no mitigation measures were proposed. Conditions of the noise environment associated with the Proposed Action and its alternatives reviewed for this Draft Supplemental EIS remain the same as they were during preparation of the 2006 Draft EIR/EIS and 2008 Final EIR/EIS. There are no sensitive receptors (e.g. schools, hospitals, residences) in the vicinity of the project area. The noise effects on the environment due to Alternatives 5 through 8 would be the same as for the Proposed Action, but because these alternatives would reduce the operating life of the mine, these impacts would be of slightly shorter duration than under the Proposed Action.

The mining operations could have an effect on Peninsular bighorn sheep, especially during lambing season. An analysis of any potential effects to biological resources resulting from blasting and crushing activities is included in Chapter 3.4 Vegetation and Wildlife.

Public Health and Safety: The process of quarrying raw ore material involves activities such as blasting and heavy equipment use that could generate potential health and safety impacts on the public and Quarry employees. Mitigation Measures 3.13-2a, 3.13-2b, and 3.13-3, presented in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS and included in Appendix E of this document, would address the impacts associated with the Proposed Action and Alternatives 2 through 4. Alternatives 5 through 8 would reduce the amount of gypsum mined over time, but the mining techniques and reclamation methods would be the same. The effects of these alternatives would be the same as the Proposed Action. No new impacts on public health and safety were identified.

3.10.4 Cumulative Effects

3.10.4.1 Geographic Scope of the Cumulative Effects Analysis

The geographic area of cumulative projects includes the areas accessible to the Quarry and Plant. Chapter 3.8 (Recreation) fully describes those areas.

July 2019 3.10-4 U.S. Gypsum Draft SEIS Chapter 3.10: Other Resource Areas

3.10.4.2 Timeframe of the Cumulative Effects Analysis

The timeframe of the cumulative effects analysis is considered to be the life of the Proposed Action or its alternatives, estimated at a maximum 73 years of Quarry operations, an additional 7 years of Plant operations, and an additional estimated 10 years for decommissioning the Plant and final reclamation/revegetation at the Quarry and pipeline alignments.

3.10.4.3 Past, Present and Reasonably Foreseeable Actions

Most of the projects listed and mapped in Appendix F (Table 4.1-1 and Figure 4.1-1b) that are in the vicinity of the project area have undergone independent environmental review pursuant to NEPA and/or CEQA, and their available findings were considered in the analysis. Other projects will be subject to environmental review prior to approval. Even if environmental review has not been completed for the cumulative projects described in Table 4.1-1, their potential effects were considered herein to determine any potential for cumulative impacts analyses. Cumulative effects were identified with respect to land scarring and vegetation clearance. Activities associated with the Proposed Action or its alternatives include revegetation following pipeline installation or completion of each mining phase.

The effects of this project would not combine cumulatively with the effects of projects listed in Appendix F. The visual impacts of this project would be resolved during reclamation. The noise, hazards and hazardous materials, impacts on public health and safety, and traffic patterns associated with this project are so geographically distant from the effects of other projects in the scope of this analysis that they would not combine cumulatively.

3.10.5 Mitigation Measures

Measures were developed and presented in the 2006 Draft EIR/EIS or 2008 Final EIR/EIS to mitigate the project’s potentially adverse effects in the areas of Visual Resources, Hazards and Hazardous Materials, and Public Health and Safety. As discussed above, neither the Proposed Action nor its alternatives evaluated in this Draft Supplemental EIS would result in any adverse impacts requiring additional mitigation in the areas of Visual Resources, Hazards and Hazardous Materials, Traffic and Circulation, Acoustics/Noise, and Public Health and Safety.

3.10.6 Residual Effects after Mitigation

With implementation of the previously proposed mitigation measures, impacts on Visual Resources, Hazards and Hazardous Materials, Traffic and Circulation, Acoustics/Noise, and Public Health and Safety would be avoided or substantially reduced. No new mitigation measures are proposed for the Proposed Action or any of its alternatives. As a result, the proposed project would result in no unavoidable adverse impacts after the mitigation measures have been applied.

U.S. Gypsum Draft SEIS 3.10-5 July 2019 Chapter 3.11: Irreversible and Irretrievable Commitment of Resource

3.11 IRREVERSIBLE AND IRRETRIEVABLE COMMITMENT OF RESOURCES

The Proposed Action and Alternatives 2 through 4 were analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS for their potential to cause an irreversible or irretrievable commitment of resources. That analysis indicated that the project would commit the use of nonrenewable energy sources for quarrying, mineral resources extracted, water used at both the Quarry and the Plant, and emissions into the air. This section addresses new information available since publication of the earlier environmental documents, new effects of the Proposed Action and its alternatives may have on these resources within the affected environment, and any effects that were not analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

The BLM NEPA Handbook (H-1790-1 Sec. 9.2.9), the NEPA Guidelines (40 CFR 1502.16 require a discussion of any irreversible or irretrievable commitments of resources which would be caused by implementation of the project, the relationship between short-term uses and long- term productivity of the environment, and any growth-inducing impacts. A commitment of a resource is considered irreversible when the primary or secondary impacts from its use limit the future options for its use. An irretrievable commitment refers to the use or consumption of a resource that is neither renewable nor recoverable for use by future generations. The use of nonrenewable resources such as metal, wood, fuel, paper, aggregate and other natural resources such as gypsum ore is considered irretrievable in that they would be used for a proposed action when they could have been conserved or used for other purposes. This chapter also considers whether the potential long-term or permanent effects of the project represent the irretrievable or irreversible commitment of the Yuha Basin ACEC, waters of the United States, and Peninsular bighorn sheep (PBS) critical habitat.

Gypsum Resources: The quarrying activities associated with the Proposed Action would irreversibly commit nonrenewable gypsum resources. Approximately 140 million tons of gypsum ore would be mined over the projected life of the mine, assuming that mining continues at the maximum rate authorized under the current air quality permit. However, the gypsum is privately owned, and would not have been conserved or used for any other purposes.

Yuha Basin ACEC: The potential effect of this project on the various environmental resources for which the ACEC was designated are discussed in the subsections of Chapter 3. None of the environmental resources present in the ACEC would be irreversibly or irretrievably consumed or lost for other uses. Ground disturbed by activities associated with the Proposed Action or its alternatives would be reclaimed, and therefore would not result in a permanent loss of land use. Tamarisk would be removed to mitigate for impacts due to disturbance above the surface disturbance cap, as described in Chapter 3.4. Tamarisk is not used for any purposes that would be impacted by removing it from these locations; therefore it does not represent an irretrievably or irreversibly lost resource. The Plant pipeline (BLM case file number CACA 044014) would be partially located in the Yuha Basin ACEC, which is within designated California Desert National Conservation Lands (NCLs). NCLs are nationally significant landscapes within the CDCA with outstanding cultural, ecological, and scientific values. NCLs incorporate the ACEC site-specific management objectives and use allocations identified in the Special Unit Management Plans. This project would not irreversibly or irretrievably alter the values of NCLs that are present in the Yuha ACEC.

U.S. Gypsum Draft SEIS 3.11-1 July 2019 Chapter 3.11: Irreversible and Irretrievable Commitment of Resource

Waters of the United States: The Proposed Action would result in permanent losses to waters of the United States in the Quarry, and both temporary and permanent impacts along the proposed pipeline alignments as described in Chapter 3.3 of this document. These impacts would be minimized or avoided through measures described in Section 3.3.6. Implementation of mitigation required in permits obtained for the project, including permits required under Sections 401 and 404 of the Clean Water Act and Section 1602 of the California Fish and Game Code would reduce the project’s impacts on jurisdictional waters both during and after the life of the project. Reclamation in the Quarry and at the site of any pumping facilities at the Westside Main Canal would ensure that the functionality of these waters of the United States would continue after each quarrying phase is completed and at the end of the project life.

Peninsular Bighorn Sheep Designated Critical Habitat: The Proposed Action would affect critical habitat for PBS as described in Chapter 3.4. The analysis of impacts indicated that the amount of critical habitat impacted by the project would be small compared with the designated critical habitat in Recovery Region 8, identified by the USFWS in the PBS Recovery Plan. Further, the majority of the critical habitat in Recovery Region 8 is either in BLM wilderness or within Anza- Borrego State Park and is well protected. The impacts of the Proposed Action on PBS critical habitat within the mine boundaries is not considered irreversible because the project would restore and revegetate the mine areas after mining operations are complete. Other minimization measures include habitat restoration and revegetation; critical habitat acquisition, preservation, and replacement; monitoring by qualified biologists; preconstruction surveys and relocation of certain special status species out of harm’s way; and supporting CDFW’s monitoring of specific PBS populations. The BLM will consult with the USFWS and obtain a Biological Opinion. Critical habitat on public lands affected by the project would be replaced subject to review and approval by the BLM and the USFWS.

Other Resources: The operations conducted under the Proposed Action would consume oil, gasoline, natural gas, diesel, water, and other nonrenewable resources for equipment and other needs. Table 3.11-1 shows the rate at which these non-renewable resources were used in the one- year period between 2017 and 2018, according to USG’s records, and projects the consumption of these resources for the life of the quarry beyond 2018, assuming 140 million tons of gypsum would be mined. At the conclusion of mining operations, the Quarry and the pipeline rights-of- way would be reclaimed and revegetated allowing the potential for re-use of the land, and no further demand for non-renewable resources would occur with respect to the Proposed Action or its alternatives.

Table 3.11-1 Projected Use of Non-Renewable Resources for USG Expansion Project 2017-18 Annual Use for Project Total Use Over Total Gypsum Life of Gypsum Reserve Non-Renewable Mined/Processed (Beginning 2018-19) Total Resource (0.78 mt) Use/Ton 140 mt Grease 4,000 gallons 0.005 gallons 700,000 gallons Oil 6,247 gallons 0.008 gallons 1,120,000 gallons Diesel Fuel 129,524 gallons 0.166 gallons 23,240,000 gallons Gasoline 8,156 gallons 0.010 gallons 1,400,000 gallons Electricity 38,808,306 KWh 49.754 KWh 6,965,560,000 KWh Natural Gas 1,393,600 Btu 1.786 Btu 250,040,000 Btu Propane 77,948 gallons 0.099 gallons 13,860,000 gallons

July 2019 3.11-2 U.S. Gypsum Draft SEIS Chapter 3.12: Growth Inducing Impacts

3.12 GROWTH INDUCING IMPACTS

The effect of the Proposed Action and its alternatives on factors inducing growth were analyzed in Section 4.4 (Growth Inducing Impacts) of the 2006 Draft EIR/EIS. This section addresses the impacts of the Proposed Action and its alternatives on growth inducement in the affected environment that have changed or were not analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS.

BLM NEPA Handbook (H-1790-1 Sec. 9.2.9) and regulations (40 CFR 1508.8) require the description and analysis of the environmental effects and impacts of the alternatives analyzed, including indirect effects that may induce growth (40 C.F.R. 1508.8(b)). Typically, the growth- inducing potential of a project would be considered significant if it would foster growth or a concentration of population above what is assumed in local and regional land use plans, or in projections made by regional planning authorities. Significant growth impacts could also occur if a project would provide the infrastructure or service capacity to accommodate growth levels beyond those permitted by local or regional plans and policies.

Increased development and growth in an area depend on a variety of factors, including employment and other opportunities. Increased production at the Plant could occur if the rate of quarrying were expanded to meet future market demands. USG estimates that it could increase employment at the Plant by up to 140 people, likely from the Ocotillo and El Centro region. The increase represents 0.01% of the total El Centro/Ocotillo regional employment base from which the additional employees are expected to be drawn. New employees hired from within the region likely would not relocate for employment. However, housing is available in the El Centro market area to accommodate the increase. The addition of 140 employees would also create a small, secondary effect on the local economy such as increased commerce and consumer spending in local communities, proportional to the increase in USG employment. Most of the economic effects are expected to occur within the El Centro Region because of its proximity to the project. The likelihood that new employees would come from within the same region as the project suggests that the increase in employment would be neutral with respect to the potential for inducing growth in the area.

The infrastructure and facility improvements related to the project would be privately owned by USG and designed specifically to meet the needs of the Quarry and Plant. They would not be available for use by other developers. Therefore, the project would not induce the development of additional housing or other developments that would rely on new utility services. Access to the area associated with the Proposed Action already exists; the project would not create new access into areas previously inaccessible for development.

The project would not result in direct inducement for population growth, nor would it result in changes to land use designations or utility infrastructure necessary for other developments to induce population growth.

U.S. Gypsum Draft SEIS 3.12-1 July 2019 Chapter 4: Consultation, Coordination, and Public Involvement

CHAPTER 4: CONSULTATION, COORDINATION, AND PUBLIC INVOLVEMENT

4.1 INTERRELATIONSHIPS/INTERAGENCY COORDINATION

The Federal Land Policy and Management Act (FLPMA; 43 USC 1701 et seq) authorizes the BLM to grant rights-of-way for various purposes including water and electrical transmission lines. The CEQ regulations (40 C.F.R. § 1501.6) provide for and describe lead and cooperating agency status and authorize other federal agencies to cooperate with the BLM in developing environmental documents. Regulations also allow an agency to adopt another agency’s environmental documents as a basis for its decisions (40 CFR 1506.3(a)).

4.1.1 The USACE and the USEPA

The USACE directed USG to analyze the hydrologic reaction of waterways in the project area to storms of various recurrence intervals, and to verify the findings in the field. The USACE, the BLM, and USG discussed the results of the hydrological model and of preliminary jurisdictional delineation during a meeting on April 13, 2018. The USACE confirmed that the initial data collection was appropriate, agreed with the approach for the jurisdictional delineation, and agreed with the findings to date. BLM coordinated with the USACE between April 2018 and February 2019 on the range of alternatives included in this Draft Supplemental EIS, and the alternatives identified in Chapter 2 reflect the USACE’s input.

The USEPA and the USACE established policy and procedures in 1990 to be used in determining the type and level of mitigation necessary to demonstrate compliance with the CWA Section 404(b)(1) Guidelines ("Guidelines"). The policies establish guidelines for carrying out the 1989 Memorandum of Agreement (MOA) that expresses the USACE’s and USEPA’s explicit intent to implement the objectives of the CWA. The USACE coordinated with the USEPA during preparation of this Supplemental EIS.

4.1.2 Endangered Species Act: Section 7 Compliance

The USFWS has jurisdiction to protect threatened and endangered species under the ESA (16 USC Section 1531 et seq.). Formal consultation with the USFWS under Section 7 of the ESA is required for any federal action that may adversely affect a federally listed species. The BLM will request formal consultation for this project with its submittal to USFWS of a Biological Assessment (BA) of the project impacts on federally listed species and designated critical habitat. Following review of the BA, the USFWS will issue a Biological Opinion (BO) on whether the proposed activity would jeopardize the continued existence of a listed species or result in the destruction or adverse modification of designated critical habitat.

4.1.3 National Historic Preservation Act: Section 106 Compliance

The Proposed Action and its alternatives constitute an “undertaking” as defined in 36 CFR 800.16(y) and involve the type of activity that could affect historic properties (36 CFR 800.3(a)).

U.S. Gypsum Draft SEIS 4-1 July 2019 Chapter 4: Consultation, Coordination, and Public Involvement

Therefore, the BLM as the Lead Agency has the statutory responsibility for compliance with the provisions of Section 106 of the NHPA (36 CFR 800.2(a)(2)).

4.2 TRIBAL CONSULTATION

The BLM consults with Indian tribes on a government-to-government basis in accordance with several authorities including NEPA, the NHPA, the American Indian Religious Freedom Act (AIRFA), and Executive Order 13175. Under Section 106 of the NHPA, the BLM consults with Indian tribes as part of its responsibilities to identify, evaluate, and resolve adverse effects on historic properties affected by BLM undertakings. To date, the BLM has identified and invited 14 federally recognized Indian tribes and one non-federally recognized Indian tribe to consult on this project. These include the Barona Band of Mission Indians, Campo Band of Mission Indians, Cocopah Indian Tribe, Ewiiaapaayp Band of Kumeyaay Indians, Fort Yuma Quechan Indian Tribe, Jamul Indian Village, Kwaaymii Laguna Band of Indians, La Posta Band of Kumeyaay Indians, Manzanita Band of Kumeyaay Indians, Mesa Grande Band of Mission Indians, San Pasqual Band of Diegueño Indians, Iipay Nation of Santa Ysabel, Sycuan Band of Kumeyaay Nation, Torres-Martinez Desert Cahuilla Indians, and Viejas Band of Kumeyaay Indians.

The BLM sent letters dated April 24, 2018 to inform Indian tribes about the U.S. Gypsum Expansion/Modernization Project, explain the BLM’s role, and invite them to consult in a government-to-government manner and/or under Section 106. The letters also requested assistance identifying any issues or concerns about the proposed project, including the identification of sacred sites and places of traditional religious and cultural significance that could be affected by the project.

The BLM received one response from the federally recognized Indian tribes. A letter from Viejas Tribal Resource Manager Ray Teran to BLM archaeologist Katherine Crosmer, dated May 10, 2018, identified that the project site has “cultural significance or ties to Viejas” and requested the presence of a Kumeyaay Cultural Monitor during ground disturbing activities. The BLM received no other responses from tribes. The BLM will continue to update the tribes as the project progresses and seek consultation.

4.3 PUBLIC INVOLVEMENT

The BLM sought public input on the project in accordance with CEQ regulations for implementing NEPA (40 CFR 1501.7), beginning with publication of the Notice of Intent (NOI) in the Federal Register Volume 82, No. 226/ Monday November 27, 2017. The Scoping Summary Report (Appendix Q) details the public involvement process, comments received, and issues identified.

The BLM mailed letters to 32 federal, State, and local agencies identified as having special expertise or jurisdiction by law applicable to the project. The letters notified the agencies and provided an overview of the project, invited participation as a Cooperating Agency, and provided contact information.

July 2019 4-2 U.S. Gypsum Draft SEIS Chapter 4: Consultation, Coordination, and Public Involvement

The BLM hosted a public scoping meeting on Wednesday, December 13, 2017 at the Holiday Inn Express Hotel & Suites in El Centro, California to share information and gather public comments on the project. The BLM advertised the scoping meeting by direct mailings and legal ads published in two local newspapers. The outreach materials provided an overview of the proposed project; provided meeting location, date, and time; explained the purpose of the scoping meeting; identified methods for making comments; and provided contact information for questions regarding the U.S. Gypsum Expansion/Modernization Project. All materials provided an e-mail address for submitting comments. Approximately 12 individuals attended the meeting. The BLM received 13 written comment submissions between November 27, 2017 and January 11, 2018,

The environmental issues listed below were previously analyzed in the 2006 Draft EIR/EIS and 2008 Final EIR/EIS, and are incorporated by reference. Those comments previously received and the findings of the 2006 Draft EIR/EIS and 2008 Final EIR/EIS will be considered by the federal agencies in the issuance of a ROD.

 Transportation/Circulation, including increased traffic levels at Evan Hewes Highway, Interstate 8, Dunaway Road and Drew Road  Public Health and Safety, including the storage and handling of fuels, oils, and other hazardous materials, and asbestos exposure if the existing 8-inch pipeline between the water wells in Ocotillo and the Plant is removed rather than abandoned in place  Acoustics, including increased noise levels at Plant and Quarry  Hazardous Materials, including the storage and handling of fuels, oils, and other hazardous materials and explosives

New issues identified during the scoping of this Supplemental EIS are detailed in Appendix Q.

4.4 IMPLEMENTATION, MONITORING AND ENFORCEMENT

4.4.1 Implementation and Monitoring

If the project is approved, the BLM would monitor activities throughout the life of the project to ensure compliance with the terms and conditions of its authorizations, and to determine whether mitigation measures were achieving the desired effects. Effectiveness monitoring would provide empirical data of the impacts of the project, the effectiveness of mitigation, and would improve analytical procedures and the design of mitigation measures for future projects.

4.4.2 Enforcement and Adaptive Management

The BLM would incorporate adaptive management into the minimization measures for the project. Adaptive management is a system of management practices based on clearly identified outcomes, monitoring to determine if management actions are meeting outcomes, and, if not, facilitating management changes that will best ensure that outcomes are met or re-evaluate the outcomes (DOI, 2003). This system is, in effect, an adaptive NEPA process and an

U.S. Gypsum Draft SEIS 4-3 July 2019 Chapter 4: Consultation, Coordination, and Public Involvement

implementation tool that goes beyond the traditional “predict-mitigate-implement” model and incorporates the “predict-mitigate-implement-monitor-adapt” adaptive management model.

Adaptive management allows agencies, in their NEPA reviews, to establish and analyze mitigation measures that are projected to result in the desired environmental outcomes, and identify those mitigation principles or measures that it would apply in the event the initial mitigation commitments are not implemented or effective (CEQ, 2011).

4.5 INDIVIDUALS CONSULTED AND LIST OF SUPPLEMENTAL EIS PREPARERS

U.S. Bureau of Land Management, Lead Federal Agency

Thomas Zale, El Centro Field Office Manager Miriam Liberatore, Project Manager, Planning & Environmental Coordinator Carrie Sahagun, Assistant Field Manager – Resources and Planning Kody Shellhouse, Geologist Steve Razo, Public Affairs Officer Liz Meyer Shields, Environmental Protection Officer Camden Bruner, Wildlife Biologist Tristan Riddell, Realty Specialist Kate Crosmer, Archaeologist Mark Massar, District Wildlife Biologist

U.S. Army Corps of Engineers, Cooperating Agency

Michelle (Shelly) Lynch, South Coast Branch Chief Kyle J. Dahl, Team Lead, South Coast Branch

U.S. Environmental Protection Agency (Region 9), Cooperating Agency

Hugo Hoffman, NEPA Reviewer Megan Fitzgerald, Life Scientist Clifton Meek, Life Scientist

Lilburn Corporation, Contractor

Steve Lilburn, Principal-in-Charge Cheryl Tubbs, Project Director Steve Kupferman, Principal Geologist Lorraine Bueno, Environmental Analyst Megan Stark, Environmental Analyst

July 2019 4-4 U.S. Gypsum Draft SEIS Chapter 4: Consultation, Coordination, and Public Involvement

Subconsultants to Contractor

Aspen Environmental Group Scott White, Senior Biologist Justin Wood, Senior Biologist

Dudek Ron Schnabel, Senior Hydrogeologist Jonathan Martin, Watershed Hydrologist Tricia Wotipka Priest, Senior Wetlands Regulatory Specialist

Hernandez Environmental Services, Inc. Juan Hernandez, Principal Biologist

Pacific Legacy John Holson, Principal Investigator Lisa Holm, Senior Archaeologist

Paleo Solutions Geraldine Aron, Principal Investigator

U.S. Gypsum Company, Applicant

Luis Carrazco, Plant Manager John Bowsher, Quarry Manager Lonnie Dyck, Director, AM-Maintenance John M. Bowman, Elkins Kalt Weintraub Reuben Gartside LLP, Legal Counsel

U.S. Fish and Wildlife Service

Felicia Sirchia, Fish & Wildlife Biologist

California Department of Fish and Wildlife

Charles Land, Environmental Scientist Randy Botta, Senior Environmental Scientist (Peninsular Bighorn Sheep Specialist)

U.S. Gypsum Draft SEIS 4-5 July 2019 Chapter 5: References

CHAPTER 5: REFERENCES

Aspen Environmental Group. Biological Resources Technical Report, United States Gypsum Company Expansion and Modernization Project, May 2018.

Bradford, G.R., Change, A.C., Page, A.L., Bakhtar, D., Frampton, J.A., Wright, H. 1996. Background Concentrations of Trace and Major Elements in California Soils. Kearney Foundation of Soil Science Division of Agriculture and Natural Resources – University of California. California Department of Parks and Recreation 2013 Historic Property Data File for Imperial County. On file at the South Coastal Information Center, San Diego, California.

California State Clearinghouse, Office of Planning and Research. CEQAnet Database accessed on May 14, 2018.

City of Brawley Community Development Services. “City of Brawley Project Descriptions” downloaded from: http://www.brawley- ca.gov/cms/kcfinder/upload/files/planning/May%202018.%20RECENT%20PROJECTS %20UPDATED.pdf on May 2, 2018.

City of El Centro Community Development Department. “City of El Centro Community Development Department Planning & Zoning Division Project List Monthly Status Report April 2018” downloaded from: http://www.cityofelcentro.org/userfiles/file/Planning/Monthly%20Reports/2018/4%20- %20April%202018.pdf on May 2, 2018.

Council on Environmental Quality. National Environmental Policy Act, 1997.

County of Imperial. Imperial County Comprehensive Economic Development Strategy. November 1, 2018.

County of Imperial General Plan Elements. County of Imperial. 2008 and Updates.

County of Imperial/U.S. Bureau of Land Management. United States Gypsum Company Expansion/Modernization Project, Imperial County, California Volumes I and II Draft Environmental Impact Report/Environmental Impact Statement, April 2006.

County of Imperial/U.S. Bureau of Land Management. United States Gypsum Company Expansion/Modernization Project, Imperial County, California Volumes I and II Final Environmental Impact Report/Environmental Impact Statement, January 2008.

Dudek. Hydrologic and Water Quality Study for the U.S. Gypsum Company Supplemental Environmental Impact Study (EIS), Plaster City, CA, October 2017.

U.S. Gypsum Draft SEIS 5-1 July 2019 Chapter 5: References

Dudek. Hydrologic and Water Quality Study for the U.S. Gypsum Company Supplemental Environmental Impact Study (EIS), Plaster City, CA, April 2018.

Dudek. US Gypsum Quarry – Preliminary Alternative Berm Analysis, May 9th, 2018.

Hernandez Environmental Services. Jurisdictional Delineation for United States Gypsum Company Plaster City Expansion/Modernization Project, November, 2016.

Holm, L. US Gypsum Supplemental EIS Phase II, Cultural Resource Evaluation for P-13- 008323 (CA-IMP-7816/H) (Project No. 3215-02). On file with the US Department of the Interior, Bureau of Land Management, El Centro Office. El Centro, California. 2018.

Holmes, A., and J. Nadolski. Archaeological Investigations for the U.S. Gypsum Company Quarry Expansion and Water Pipeline Replacement Project in Imperial County, California. On file with Pacific Legacy, Inc., Berkeley, California. 2003.

Holson, J. US Gypsum Supplemental EIS Inventory Survey for Avoidance of CA-IMP-2355, CA-IMP-4391/H, and CA-IMP-269 (Project No. 3215-02). On file with the US Department of the Interior, Bureau of Land Management, El Centro Office. El Centro, California. On file with the US Department of the Interior, Bureau of Land Management, El Centro Office. El Centro, California. 2018.

Imperial County Planning & Development Services. “Imperial County Planning & Development Services Planning Project Status Report February 2016” downloaded from http://www.icpds.com/CMS/Media/Planning-Staff-Report-Updated--020416.pdf on May 2, 2018.

Imperial County Air Pollution Control District. Final 2009 Imperial County State Implementation Plan for Particulate Matter Less Than 10 Microns in Aerodynamic Diameter. August 11, 2009.

Imperial County Air Pollution Control District. Imperial County 2017 State Implementation Plan for the 8-hour Ozone Standard. September 2017.

Imperial County Air Pollution Control District. Imperial County 2013 State Implementation Plan for the 2006 24-hour PM2.5 Moderate Non-Attainment Area. December 2, 2014.

Imperial County Planning and Development Services Department. Imperial County Conservation and Open Space Element. March 8, 2016.

Levick, L.R., Fonseca, J., Semmens, D.J., Stromberg, J., Tluczek, M., Leidy, R.A., Scianni, M., Guertin, P.D., Kepner, W.G. 2008. The Ecological and Hydrological Significance of Ephemeral and Intermittent Streams in the Arid and Semi-arid American Southwest. 2008 U.S. Environmental Protection Agency and USDA/ARS Southwest Watershed Research Center, EPA/600/R-08/134, ARS/233046, 116 pp.

July 2019 5-2 U.S. Gypsum Draft SEIS Chapter 5: References

Pacific Legacy, Inc. Cultural Resources Report For The Us Gypsum Company Expansion/Modernization Project Supplemental EIS, Imperial County, California. On file with the US Department of the Interior, Bureau of Land Management, El Centro Office. El Centro, California. 2018.

Paleo Solutions, Inc. Paleontological Technical Study, United States Gypsum Company Expansion/Modernization Project, Bureau of Land Management, May 15, 2018

United States Gypsum Company. 2003 Plan of Operations Revised, April 16, 2018.

United States Gypsum Company. Notices of Location of Mill Site Claims, January 3, 2018.

United States Gypsum Company. Recorded Notices of Location of Mill Site Claims, December 20, 2017. U.S. Bureau of Land Management (BLM). The California Desert Conservation Area Plan 1980.

U.S. Bureau of Land Management (BLM). Assignment of Right-of-Way Permit to Pacific Portland Cement Company, November 5, 1931.

U.S. Bureau of Land Management (BLM). California Desert Conservation Area Plan Amendment for the Western Colorado Desert Route of Travel Designation, 2002.

U.S. Bureau of Land Management (BLM). Desert Renewable Energy Conservation Plan, September 2016.

U.S. Bureau of Land Management (BLM). Draft Desert Renewable Energy Conservation Plan EIR/EIS, Chapter III.14. BLM Land Designations, Classifications, Allocations, and Lands with Wilderness Characteristics, August 2014.

U.S. Bureau of Land Management (BLM). Draft Desert Renewable Energy Conservation Plan EIR/EIS, Chapter III.1. BLM Outdoor Recreation, August 2014.

U.S. Bureau of Land Management (BLM). Draft Desert Renewable Energy Conservation Plan Appendix B, Lake Cahuilla Ecoregion, December 1969.

U.S. Bureau of Land Management (BLM. ePlanning Project Search. Accessed on May 4, 2018.

U.S. Department of Agriculture Forest Service. State Level Datasets. “Direct Protection Areas for Wildland Fire Protection” downloaded June 13, 2016 from: http://www.fs.usda.gov/detail/r5/landmanagement/gis/?cid=STELPRDB5327836

U.S. Department of the Interior, Bureau of Land Management (BLM) and California State Historic Preservation Officer (SHPO). State Protocol Agreement among the California State Director of the Bureau of Land Management and the California State Historic Preservation Officer and the Nevada State Historic Preservation Officer Regarding the Manner in Which the Bureau of Land Management Will Meet Its Responsibilities Under the National Historic Preservation Act and the National Programmatic Agreement among

U.S. Gypsum Draft SEIS 5-3 July 2019 Chapter 5: References

the BLM, the Advisory Council on Historic Preservation, and the National Conference of State Historic Preservation Officers. Accessed May 2018. Available at: https://www.blm.gov/sites/blm.gov/files/ CA%20Protocol.pdf. 2014.

U.S. Department of Labor Statistics. Local Area Unemployment Statistics. Labor Force Data by County, 2010 Annual Averages accessed on April 25, 2018.

U.S. Census Bureau. “American Community Survey 5-year estimates,” 2016.

U.S. Census Bureau. 2010 Census Interactive Population Search.

July 2019 5-4 U.S. Gypsum Draft SEIS