Geotechnical and Geologic Investigations for the Anderson Dam Seismic Retrofit Project – Phase 1B Draft Mitigated Negative Declaration Project Number 91864005 September 2014 Santa Clara Valley Water District 5750 Almaden Expressway San José, CA 95118-3614 District Board of Directors Dennis Kennedy District 1 Nai Hseuh District 5 Barbara Keegan District 2 Tony Estremera, Chair District 6 Richard P. Santos District 3 Brian A. Schmidt District 7 Linda J. LeZotte District 4 Prepared by: 2365 Iron Point Road, Suite 300 180 Grand Avenue, Suite 1405 Folsom, CA 95630 Oakland, CA 94612 Santa Clara Valley Water District Table of Contents A. INTRODUCTION ...................................................................................................................................... 1 B. PROJECT DESCRIPTION ....................................................................................................................... 4 1.0 PROJECT OVERVIEW .............................................................................................................................. 4 1.1 Project Location .............................................................................................................................. 4 1.2 Purpose and Need .......................................................................................................................... 7 2.0 INVESTIGATION LOCATIONS .................................................................................................................... 7 2.1 Dam Embankments and Spillway ................................................................................................... 7 2.2 Borrow Areas ................................................................................................................................ 10 3.0 INVESTIGATION METHODS .................................................................................................................... 10 3.1 Rock Core Drilling ......................................................................................................................... 10 3.2 Rotary Wash Drilling ..................................................................................................................... 10 3.3 Test Pit .......................................................................................................................................... 11 3.4 Fault Trenches .............................................................................................................................. 11 4.0 SITE ACCESS ...................................................................................................................................... 12 5.0 INVESTIGATION WORK SCHEDULE ........................................................................................................ 13 6.0 ENVIRONMENTAL PROTECTION MEASURES ........................................................................................... 13 C. ENVIRONMENTAL EVALUATION ........................................................................................................ 23 1.0 INITIAL STUDY CHECKLIST .................................................................................................................. 27 2.0 BACKGROUND..................................................................................................................................... 23 3.0 ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED............................................................................. 24 4.0 CEQA ENVIRONMENTAL CHECKLIST .................................................................................................... 25 D. DETERMINATION .................................................................................................................................. 82 E. LIST OF INITIAL STUDY PREPARERS ................................................................................................ 83 F. REFERENCES ....................................................................................................................................... 84 Appendix A – Air Quality Modeling Results Appendix B – Mitigation Monitoring and Reporting Program Summary Table Draft Mitigated Negative Declaration Page i September 2014 Geotechnical and Geologic Investigations for the Anderson Dam Seismic Retrofit Project – Phase 1B Santa Clara Valley Water District List of Figures Figure 1 Project Location Figure 2 Phase 1B Project Activities List of Tables Table 1. Proposed Investigation Locations and Types Table 2. Proposed Investigation Methods, Area of Disturbance, and Access Table 3. VHP Conditions, AMMs, and BMPs Incorporated into Project Table AQ-1. Air Quality Thresholds of Significance Table BIO-1. Special-status Plant Species with Potential to Occur on the Project Site Table BIO-2. Special-status Wildlife Species with Potential to Occur on the Project Site Table LU-1. Property Details Table NV-1. Noise Level Restrictions for Construction Equipment Table NV-2. Construction Equipment Noise Emission Levels Table CUM-1. Reasonably Foreseeable Future Projects that May Cumulatively Affect Resources of Concern for the Proposed Project Table CUM-2. Summary of Cumulative Significant Impacts and Proposed Project’s Contribution Draft Mitigated Negative Declaration Page ii September 2014 Geotechnical and Geologic Investigations for the Anderson Dam Seismic Retrofit Project – Phase 1B Santa Clara Valley Water District Key Terminology Beneficial Impact: A project impact is considered beneficial if it would result in the enhancement or improvement of an existing physical condition in the environment – no mitigation is required. Best Management Practices: Standard operating procedures that have been identified as methods, activities, procedures, or other management practices for the avoidance or minimization of potential adverse environmental effects. They have been designed for routine incorporation into project designs and represent the “state of the art” impact prevention practices. Less-than-Significant Impact: This is indicated in the Initial Study checklist where the impact does not reach the standard of significance set for that factor and the project would therefore cause no substantial change in the environment (no mitigation needed). Mitigation Measures: Mitigation includes (a) avoiding the impact altogether by not taking a certain action or parts of an action; (b) minimizing impacts by limiting the degree or magnitude of the action and its implementation; (c) rectifying the impact by repairing, rehabilitating, or restoring the impacted environment; (d) reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action; and (e) compensating for the impact by replacing or providing substitute resources or environments.1 No impact: This is indicated in the Initial Study where, based on the environmental setting, the stated environmental factor does not apply to the Proposed Project. Potentially Significant Impact: An environmental effect that may cause a substantial adverse change in the environment; however, additional information is needed regarding the extent of the impact to make a determination of significance. For the purposes of review such are treated as significant impacts and mitigation measures are proposed. Significance Criteria: A set of criteria used by the lead agency to determine whether an impact would be considered significant. The District relied upon the significance criteria set forth in the CEQA Guidelines and criteria based on the regulatory standards of local, state, and federal agencies. Significant Impact: An impact that would likely result in a substantial adverse change in the physical conditions of the environment. Mitigation measures and/or project alternatives are identified to avoid or reduce these effects to the environment. 1 Authority cited: Sections 21083 and 21087, Public Resources Code; Reference: Sections 21002, 21002.1, 21081, and 21100(c), Public Resources Code. Draft Mitigated Negative Declaration Page i September 2014 Geotechnical and Geologic Investigations for the Anderson Dam Seismic Retrofit Project – Phase 1B Santa Clara Valley Water District Page intentionally left blank. Draft Mitigated Negative Declaration Page iii September 2014 Geotechnical and Geologic Investigations for the Anderson Dam Seismic Retrofit Project – Phase 1B Santa Clara Valley Water District A. INTRODUCTION 1.0 Organization of this Document This document is intended to assist the reader in understanding the potential impacts that the project may have on the environment and to fulfill the California Environmental Quality Act (CEQA) (Public Resources Code Section 21000 et seq.). Section A indicates the purpose under CEQA, explains the manner in which significance is determined for Project impacts, sets forth the public participation process, and summarizes applicable state and federal regulatory requirements. Section B describes the location and features of the project. Section C evaluates the potential impacts through the application of the CEQA Initial Study Checklist questions to project implementation. Section D contains the CEQA determination based on information provided in Section C. Section E lists the contributors, and Section F supplies references used in its preparation. 2.0 Purpose of the Mitigated Negative Declaration The Santa Clara Valley Water District (District), acting as the Lead Agency, prepared a draft Mitigated Negative Declaration (MND) to provide the public, responsible agencies and trustee agencies with information about the potential environmental effects of the proposed Geotechnical and Geologic Investigations for the Anderson Dam Seismic Retrofit Project – Phase 1B (Proposed Project, or Project). The MND was prepared consistent with CEQA, the CEQA Guidelines (Title 14, California Code of Regulations 15000 et seq.), and District procedures for implementation of CEQA (Environmental Management System – Environmental Planning Q520D01). CEQA requires that public agencies such as the District identify the significant adverse impacts and beneficial environmental effects of their actions. Beneficial impacts should be encouraged and expanded where possible and adverse impacts should be avoided or minimized, or mitigated in cases where avoidance and minimization are not possible. In addition to acting as the CEQA Lead Agency for its projects, the District’s mission includes objectives to conduct its activities in an environmentally sensitive manner as a steward of Santa Clara Valley watersheds. The District strives to preserve the natural qualities, scenic beauty and recreational uses of Santa Clara Valley’s waterways by using methods that reflect an ongoing commitment to conserving the environment. 3.0 Decision to Prepare a Mitigated Negative Declaration for this Project The Initial Study (Section C) for the Proposed Project identifies potentially significant effects on air quality; biological resources; cultural resources; hazards and hazardous materials; and noise. Mitigation measures have been proposed for the project to reduce such effects to less- than-significant levels; and therefore, the proposed Mitigated Negative Declaration is consistent with CEQA Guidelines §15070 which indicate that a mitigated negative declaration is appropriate when: The Project Initial Study identifies potentially significant effects, but: a. Revisions to the Project plan were made that would avoid, or reduce the effects to a point where clearly no significant effects would occur, and b. There is no substantial evidence that the Project, as revised, may have an significant effect on the environment. Draft Mitigated Negative Declaration Page 1 September 2014 Geotechnical and Geologic Investigations for the Anderson Dam Seismic Retrofit Project – Phase 1B Santa Clara Valley Water District 4.0 Public Review Process This draft MND will be calculated to local and state agencies, interested organizations, and individuals who may wish to review and provide comments on the Project description, the proposed mitigation measures, or other aspects of the report. The publication will commence the 30-day public review period per CEQA Guidelines §15105(b) beginning on September 19, 2014 and ending on October 20, 2014. The draft MND and supporting documents are available for review at: • Santa Clara Valley Water District Headquarters Building 5700 Almaden Expressway San José, CA 95118 Copies of the report are available for review at: • Morgan Hill Library 660 West Main Avenue Morgan Hill, California 95037 • Posted on the district website: http://www.valleywater.org/PublicReviewDocuments.aspx, or • Via written request for a copy from the District. Written comments or questions regarding the draft MND should be submitted to the name and address indicated below. Submittal of written comments via e-mail would greatly facilitate the response process. Liza McNulty Santa Clara Valley Water District 5750 Almaden Expressway San José, CA 95118-3614 Phone: (408) 630-2562 e-mail: [email protected] The proposed Mitigated Negative Declaration along with any comments will be considered by the District Board of Directors prior to a decision on the project. 5.0 Interagency Collaboration and Regulatory Review The CEQA review process is intended to provide both trustee and responsible agencies with an opportunity to provide input into the Project. Trustee agencies are state agencies that have authority by law for the protection of natural resources held in trust for the public. Responsible agencies are those that have some responsibility or authority for carrying out or approving a project; in many instances these public agencies must make a discretionary decision to issue a permit; provide right-of-way, funding or resources that are critical to proceeding. In this instance, the United States Army Corps of Engineers (USACE), State Water Resources Control Board (SWRCB), and San Francisco Bay Regional Water Quality Control Board (RWQCB) are considered responsible agencies and the California Department of Fish and Wildlife (CDFW) is considered a trustee agency. The District will work with USACE, SWRCB, RWQCB, and CDFW to ensure that the Proposed Project meets applicable policies and requirements. The District will Draft Mitigated Negative Declaration Page 2 September 2014 Geotechnical and Geologic Investigations for the Anderson Dam Seismic Retrofit Project – Phase 1B Santa Clara Valley Water District also comply with its own requirements for well permits pursuant to District Ordinance 90-1 and incidental take authorization as a co-permittee of the Valley Habitat Conservation Plan. The MND is intended to assist state and local agencies to carry out their responsibilities for permit review or approval authority over various aspects of the Project. The Project would likely require project-specific permitting and/or review as summarized in Table A-1 below. Table A-1 Summary of Agency Approvals Agency Permit/Review Required United States Army Corps of Engineers Nationwide Permit No. 6 California Department of Fish and Wildlife 1602 Lakebed Alteration Agreement State Water Resources Control Board General 401 Water Quality Certification Order No. SB12002GN San Francisco Bay Regional Water Quality Control Notice of Applicability for coverage under State Board Water Resources Control Board General 401 Water Quality Certification Order No. SB12002GN for US Army Corps of Engineers 2012 Certified Nationwide Permits District (internal) Well Construction, Destruction, and Exploratory Boring Permits Valley Habitat Plan Incidental Take Authorization Draft Mitigated Negative Declaration Page 3 September 2014 Geotechnical and Geologic Investigations for the Anderson Dam Seismic Retrofit Project – Phase 1B Santa Clara Valley Water District B. PROJECT DESCRIPTION 1.0 Project Overview The Proposed Project consists of temporary geologic and geotechnical investigations in areas adjacent to Anderson Dam. These investigations are in support of the Anderson Dam Seismic Retrofit Project (ADSRP), which is being proposed by the Santa Clara Valley Water District (District). The ADSRP would include excavation and reconstruction of the Anderson Dam embankments, mining of rock from nearby borrow areas, raising the dam crest and spillway side walls by approximately 7 feet, constructing a new intake structure in the reservoir, and constructing new outlet facilities to the spillway and creek below the dam. The ADSRP is currently in its design phase, and the Proposed Project is necessary to provide important information to support the design effort. As described in detail below, the Proposed Project consists of temporary geologic and geotechnical investigations in areas adjacent to and northeast of Anderson Dam. 1.1 Project Location The Proposed Project is located northeast and adjacent to Anderson Dam in Santa Clara County, 0.8 miles east of U.S. Highway 101 (Cochrane Road exit), about 18 miles southeast of downtown San José, and 2.5 miles northeast of downtown Morgan Hill (see Figure 1). Project sites are located within Anderson Lake County Park, upslope of Coyote Creek and along the shoreline of Anderson Reservoir (see Figure 2). The project sites are on land owned by the District. Draft Mitigated Negative Declaration Page 4 September 2014 Geotechnical and Geologic Investigations for the Anderson Dam Seismic Retrofit Project – Phase 1B