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Upper Berryessa Creek Flood Risk Management Project, Santa Clara County, California : Final Environmental Impact Report PDF

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Upper Berryessa Creek Flood Risk Management Project Santa Clara County, California Final Environmental Impact Report (State Clearinghouse No. 2001104013) January 2016 Prepared for: Prepared by: This page left blank intentionally EXECUTIVE SUMMARY ES.1 INTRODUCTION This document addresses proposed modifications to Upper Berryessa Creek within the cities of Milpitas and San Jose, California. These modifications include flood risk management improvements along 2.2 miles of Upper Berryessa Creek, stretching from I-680 downstream to Calaveras Boulevard. The primary improvements include: • Constructing a floodwall at the area identified as being most in danger of overtopping; • Excavating sediment and vegetation; • Enhancing flood passage through culverts and bridges; and • Improving access for maintenance, including sediment removal and vegetation management. As the primary water resources agency for Santa Clara County (the County), the Santa Clara Valley Water District (the District) provides water-related services including wholesale distribution, stream maintenance, and flood protection throughout the Santa Clara Valley. In order to alleviate flooding in the Upper Berryessa Creek area, the District is proposing flood risk management measures that would provide protection from the base flood (also referred to as the 100-year flood). The District has formed a partnership with the U.S. Army Corps of Engineers (USACE) to plan and implement the proposed project. The USACE is the Federal project sponsor and the District is the local sponsor. USACE would be responsible for permitting, contracting and oversight of construction activities and the District would be responsible for acquiring real property needed for the project (including temporary and permanent easements), making real property owned or to be acquired by the District for the project available for construction, and operating and maintaining the creek channel after construction is complete. As part of the process of studying the feasibility of the proposed project and its alternatives, the USACE prepared the Berryessa Creek Integrated General Reevaluation Report (GRR) and Environmental Impact Statement (EIS), which was finalized in 2014. The GRR/EIS documents the planning and evaluation process that identified the USACE’s preferred alternative, the results of hydraulic, economic, geotechnical, and other studies that informed the process, and the environmental impacts that could occur during construction and operation of the proposed project. As the GRR/EIS has been finalized, the USACE is preparing the project designs and intends to implement the selected plan. The District’s proposed project consists of the project as selected by the USACE with an improvement that would increase the level of flood protection to meet Federal Emergency Management Agency (FEMA) certification standards. The improvement that would be added to the USACE-selected project to achieve FEMA certification is increasing the length and height of a concrete floodwall located on the west bank of the creek in Reaches 2 and 3. The USACE-selected project design includes a roughly 1,300 foot long, 1.5 foot high floodwall at this location; the proposed project would increase the length of the floodwall to about 2,200 feet. The maximum height of the floodwall would be 2 feet above ground level. The District determined that construction of the proposed project could have a significant effect on the environment and is has therefore prepareding this Environmental Impact Report (EIR) in compliance with the California Environmental Quality Act (CEQA). This Draft EIR (DEIR) is intended to: • Provide a complete description of the proposed project to the public; • Inform the public of any significant impacts that could occur as a result of project implementation; • Identify measures that would avoid, reduce, or mitigate any significant effects; and Upper Berryessa Creek Flood Risk Management Project ES- i Tetra Tech Final Environmental Impact Report January 2016 • Describe and evaluate other alternatives that may feasibly accomplish the goals and objectives of the proposed project. ES.2 OBJECTIVES The District developed three project-specific objectives, which provide the basis for potential modifications to complete the proposed project. Objective 1: Reduce flood damages from Berryessa Creek upstream of Calaveras Boulevard throughout the study reach during the 50-year period of analysis beginning in 2017. Completed project would meet FEMA certification standards in all 4 project reaches. Objective 2: Use environmentally sustainable design practices in addressing the flood risk management purpose of the project wherever possible within the study reach, including taking advantage of restoration opportunities that may be pursued incidentally to the flood damage reduction purpose. Objective 3: Be consistent with Berryessa Creek Flood Risk Management Project Plan selected by USACE in the Director’s Report of May 29, 2014. ES.3 BACKGROUND Flooding within the Berryessa Creek watershed and vicinity has occurred often during the past decades. Stormwater flooding that inundates streets and yards occurs an average of at least once every 4 years. Overflow channel flooding also occurs along Upper Berryessa Creek on average of once every 10 to 20 years, which results in significant damage to homes, businesses, infrastructure, and automobiles. High rainfall events occurring in 1982, 1983, and 1998 caused extensive flooding and damage to areas along creeks in the cities of San Jose and Milpitas. As a result of these and other floods, the District and the USACE commenced studies to identify areas of Berryessa Creek and its tributaries, a part of the Coyote Watershed, that are most vulnerable to flooding. Teams of hydraulic engineers, planners, and field inspectors reviewed historic flood information, topographic maps, and other available data and reports, and prepared detailed hydraulic models of the Upper Berryessa Creek system. The resulting studies in hydraulics, economics, geotechnical issues, hazardous materials, and sediment movement resulted in the Berryessa Creek Project GRR-EIS. These studies indicate that Upper Berryessa Creek does not have sufficient capacity to contain the 1 percent (100-year) recurrence flood, meaning that destructive flooding would continue to occur unless measures are taken to expand flow capacity. The dollar value of flood damage from the 1 percent flood is estimated at $528 million in 2011 dollars (USACE 2014). ES.4 PROJECT SUMMARY Working closely with USACE, the District has developed the Upper Berryessa Creek Flood Risk Management Project, which is described and analyzed in this EIR. The proposed project would provide flood protection and flood damage reduction benefits along Upper Berryessa Creek by incorporating channel, bridge, and top of bank improvements designed to convey the 1 percent recurrence flood within its banks. The proposed project consists of the USACE-selected project with addition of a taller and longer concrete floodwall in Reaches 2 and 3 compared to the USACE-selected project. The proposed project is designed to meet FEMA certification standards. The proposed project would remove an estimated 500 parcels of land from the flood hazard zone. Under the proposed project, all work would occur downstream of I-680 and upstream of Calaveras Boulevard. The District is implementing a separate project to improve the flow conveyance capacity of Lower Berryessa Creek between Calaveras Upper Berryessa Creek Flood Risk Management Project ES- ii Tetra Tech Final Environmental Impact Report January 2016 Boulevard and the Lower Penitencia Creek confluence. Calaveras Boulevard forms the boundary between the Upper Berryessa Creek Flood Risk Management Project and the Lower Berryessa Creek Flood Protection Improvements Project. Both projects would be designed to contain the 1 percent flow without overtopping of banks. The channel of Upper Berryessa Creek would be designed with vegetated side walls to add capacity and provide bank protection within the existing right-of-way (ROW). The channel banks would be protected with biodegradable erosion control blankets and hydroseeded, an approach that has been shown in the Design Documentation Report (Tetra Tech 2015f) to be sufficient to prevent significant erosion. The channel would also have an earthen channel bottom with buried rock revetments for channel stability. The existing access road alignments would be retained and additional access added on the east bank at the downstream end of the project area. ES.5 CONSTRUCTION AND MAINTENANCE Construction of the proposed project would include excavating a wider channel, constructing a floodwall on the west bank, installing a concrete box culvert to replace an existing railroad trestle as well as installing new culverts at the mouths of Piedmont and Los Coches Creeks, revegetating affected areas, and constructing or upgrading access roads. Construction would occur over 1 to 2 years, with construction primarily occurring between May and October to coincide with the driest time of year. Construction hours would generally be during normal business hours, but after-hours work may be needed to pour concrete or replace the existing UPRR trestle with a concrete box culvert. As part of the District’s Stream Maintenance Program 2 (SMP2), after construction is complete, District maintenance staff would periodically remove sediment as needed to ensure the capacity of the channel is sufficient to convey the design flow, mow or spray vegetation to facilitate access and reduce fire hazards, and inspect access roads for erosion or blockagesobstructions. Maintenance staff would also inspect and repair structures such as rock revetment, concrete linings, and stormwater outfalls as needed. The District would also remove trash or obstacles that may hinder flood flows. Because the improved channel would more efficiently pass flood flows and would be less prone to erosion, future maintenance needs would be reduced compared to current conditions. SMP2 is an ongoing District activity that is not part of the proposed project. SMP2 activities are permitted by regulatory agencies and all SMP2 activities on Upper Berryessa Creek will be implemented in conformance with the SMP2 permits. The cumulative impacts section of this EIR addresses potential environmental effects of SMP2 activities that could add to the environmental effects of the proposed project. After construction of the proposed project is completed, the District would continue the ongoing SMP2 maintenance practices at the Upper Berryessa Creek project area, and would add measures to maintainperform inspection of the newly constructed floodwalls and culverts. Additional maintenance activities associated with the project include inspection and graffiti abatement at floodwalls and culverts, and additional access road inspections, and maintenance. These activities would occur regularly to maintain channels and structures at design conditions. ES.6 SUMMARY OF ALTERNATIVES In accordance with CEQA Guidelines § 51526.6(a), this EIR analyzes four alternatives to the proposed project. They are intended to provide a range of alternative actions that could feasibly achieve the project objectives while avoiding or substantially reducing significant environmental impacts. The alternatives are as follows: • No Project Alternative Upper Berryessa Creek Flood Risk Management Project ES- iii Tetra Tech Final Environmental Impact Report January 2016 • Alternative 2A: U.S. Army Corps of Engineers Selected Project • Alternative 2B: Expanded Incised Trapezoidal Channel (FEMA Certification Performance) • Alternative 4: Walled Trapezoidal Channel (FEMA Certification Performance) The proposed project would achieve all project objectives (see Table ES-1).The No Project Alternative would not meet project objectives and is analyzed in this EIR for comparison purposes. Alternatives 2A, 2B, and 4 would partially meet project objectives. Specifically, Alternative 2A would not meet FEMA certification standards and would only partially achieve Objective 1. Alternatives 2B and 4 would meet Objectives 1 and 2, but would not meet Objective 3 (Be consistent with USACE-selected plan). Table ES.1: Project Alternatives Compared to Project Objectives Alternative Objective 1 Objective 2 Objective 3 Proposed Project Meets Meets Meets No Project Does not meet Does not met Does not meet Alternative 2A Partially meets Meets Meets Alternative 2B Meets Meets Does not meet Alternative 4 Meets Meets Does not meet These alternatives and the proposed project are analyzed in this EIR to determine the environmentally superior alternative. Based on the evaluation of potential impacts presented in Chapters 3, 4, and 5 of the Draft EIR, the proposed project is environmentally superior because it would accomplish the project objectives (reduce flood damages, incorporate environmentally sustainable design practices, and be consistent with the USACE’s selected plan) while minimizing construction-period environmental impacts. ES.7 IMPACTS AND MITIGATION MEASURES Table ES-2 identifies potential impacts that would occur under the various alternatives. With the exception of impacts to air quality, construction noise, and emissions of greenhouse gases, all significant environmental impacts could be reduced to less than significant levels by implementing mitigation measures described at the end of each resource section. For all alternatives other than the No Project Alternative, emissions of nitrogen oxides (NOx), temporary noise impacts during construction, and greenhouse gas emissions would exceed applicable significance thresholds. Feasible measures to mitigate these impacts are identified in this EIR, but would not reduce these impacts to a less than significant level. These impacts would be significant and unavoidable under the proposed project, as well as under Alternative 2A, Alternative 2B, or Alternative 4. The cumulative impacts of the proposed project and alternatives combined with impacts from other recent, ongoing, or reasonably foreseeable projects were also assessed. This analysis found that, in combination with other projects, the proposed project would make cumulatively considerable contributions to significant cumulative impacts on air quality, noise, and greenhouse gas emissions. In all other resource categories, cumulative impacts would either be less than significant, or if the cumulative impact would be significant, the proposed project’s post-mitigation contribution to the impact would not be cumulatively considerable. ES.8 AREAS OF KNOWN CONTROVERSY The District issued a Notice of Preparation and invited individuals, organizations, and agencies to comment on the scope of the Draft EIR in October, 2001. Notable concerns focused on addressing degradation of natural resources by reducing channelization and eliminating concrete lining to the Upper Berryessa Creek Flood Risk Management Project ES- iv Tetra Tech Final Environmental Impact Report January 2016 degree possible; designing the channel to allow for natural fluvial processes to occur; positioning maintenance roads outside of the channel; and ensuring that the completed project accommodates existing storm drainage facilities at any State highway bridge crossings. USACE and the District have addressed these concerns in the project designs, as reflected in this Draft EIR. Although the proposed project evaluated in this Draft EIR is reduced in scope from the project as proposed in 2001, the design includes widened channel that will allow for more natural fluvial processes, and which has an earthen bottom except beneath bridges and culverts; maintenance roads positioned in the overbank areas except for ramps needed to allow access to the channel bottom; and storm drainage facilities that are maintained or improved relative to their original condition. Other areas of controversy have not been identified. ES. 9 ISSUES TO BE RESOLVED Consultation between the project sponsors and permitting agencies has either been initiated or will be required in order to resolve any permitting issues that may arise. USACE regulations generally require USACE to seek Section 401 water quality certification for USACE projects involving a discharge into waters of the U.S. even though USACE does not issue itself a Section 404 permit. However, the project, as a project authorized by Congress that has completed an EIS, qualifies for exemption under 33 U.S. Code 1344(r). USACE will either obtain a Section 401 water quality certification or claim exemption under 33 U.S. Code 1344(r) for the proposed project. Also, USACE will refine the project design to determine the most appropriate location and sizes of mitigation areas for planting of native tree and shrubs in accordance with the U.S. Fish and Wildlife Service Coordination Act Report of April 2013 and follow-on consultations between USACE and USFWS. Maintenance and operation of the reconstructed creek channel would be the responsibility of the District. Most maintenance activities would be similar to the creek maintenance activities currently performed under the District Stream Maintenance Program (SMP). Regulatory permits for the SMP cover vegetation management, sediment removal, bank stabilization, management of animal conflicts, and minor maintenance (e.g. fence repairs, access road maintenance, minor sediment removal of less than 25 cubic yards, graffiti abatement), which would be the same activities needed to maintain the creek after construction is complete. However, the reconstructed creek channel would be widened compared to the existing channel and the SMP permits may not account for the area of channel enlargement. If necessary maintenance activities are not covered by SMP permits, the District would obtain approval and permits for the uncovered activities from The San Francisco Bay Regional Water Quality Control Board, California Department of Fish and Wildlife, and USACE Regulatory Branch as required by law. Upper Berryessa Creek Flood Risk Management Project ES- v Tetra Tech Final Environmental Impact Report January 2016 This page left blank intentionally Upper Berryessa Creek Flood Risk Management Project ES- vi Tetra Tech Final Environmental Impact Report January 2016 Table ES.2 Summary of Significant Effects, Mitigation Measures, and Level of Significance by Alternative PROPOSED PROJECT NO PROJECT ALTERNATIVE 2A ALTERNATIVE 2B ALTERNATIVE 4 Widened Trapezoidal ALTERNATIVE USACE-Selected Alternative Expanded Incised Trapezoidal Walled Trapezoidal Channel ENVIRONMENTAL RESOURCE Channel (FEMA Certification Channel (FEMA Certification (FEMA Certification Performance) Performance), Accommodate Performance) Upstream Bypass Channel KEY: (+) Impacts greater than for Proposed Project, (=) Impacts equal to Proposed Project, (-) Impacts less than for Proposed Project, (NI) No Impact, (LS) Less than Significant Impact, (LM) Less than Significant Impact with Mitigation, (S) Significant Impact, (SU) Significant and Unavoidable Impact * Although impacts associated with these resource types were determined to be less than significant, a mitigation measure is proposed, or a measure proposed to address another significant impact would further reduce this already LTS impact. Aesthetics No significant impacts (-) No significant impacts No significant impacts No significant impacts No significant impacts BIO-B: Compensate for Trees Removed     During Construction* Significance Determination Before LS NI LS LS LS Mitigation/After Mitigation NOx emissions above (-) No significant impacts (=) NOx emissions above (+) NOx emissions above (+) NOx emissions above Air Quality BAAQMD thresholds (AIR- BAAQMD thresholds BAAQMD thresholds BAAQMD thresholds 2 and AIR-3) (AIR-2 and AIR-3) (AIR-2 and AIR-3) (AIR-2 and AIR-3) AIR-A. Reduce Construction Period Dust     Emissions AIR-B. Reduce Construction Equipment     Emissions Significance Determination S / SU NI S / SU S / SU S / SU Before Mitigation / After Mitigation Agriculture and Forestry None None None None None Significance (No Mitigation) NI NI NI NI NI Adverse impacts on (-) No significant impacts (=) Adverse impacts on (+) Adverse impacts on (+) Adverse impacts on riparian habitat and riparian habitat and riparian habitat and riparian habitat and healthy trees/shrubs (BIO- healthy trees/shrubs (BIO- healthy trees/shrubs (BIO- healthy trees/shrubs (BIO- 2).Adverse impacts on 2). 2). 2). Biological Resources bird migration (Impact Adverse impacts on bird Adverse impacts on bird Adverse impacts on bird BIO-4). migration (Impact BIO-4). migration (Impact BIO-4). migration (Impact BIO-4). Conflict with policies in Conflict with policies in Conflict with policies in Conflict with policies in Milpitas Tree Ordinance Milpitas Tree Ordinance Milpitas Tree Ordinance Milpitas Tree Ordinance (BIO-5) (BIO-5) (BIO-5) (BIO-5) vii Upper Berryessa Creek Flood Risk Management Project ES- Tetra Tech Final Environmental Impact Report January 2016 PROPOSED PROJECT NO PROJECT ALTERNATIVE 2A ALTERNATIVE 2B ALTERNATIVE 4 Widened Trapezoidal ALTERNATIVE USACE-Selected Alternative Expanded Incised Trapezoidal Walled Trapezoidal Channel ENVIRONMENTAL RESOURCE Channel (FEMA Certification Channel (FEMA Certification (FEMA Certification Performance) Performance), Accommodate Performance) Upstream Bypass Channel BIO-A. Perform Pre-Construction Nesting     Bird Surveys BIO-B. Compensate for Trees and Shrubs     Removed During Construction BIO-C. Use native grasses and forbs to     hydroseed disturbed areas. BIO-D. Provide Buffers Around Riparian     Trees Significance Determination S / LM NI S / LM S / LM S / LM Before Mitigation / After Mitigation Adverse impact on (=) No significant impacts (=) Adverse impact on (+) Adverse impact on (+) Adverse impact on historical/archaeological historical/archaeological historical/archaeological archeological site CA-SCL- site CA-SCL-593 (Impact site CA-SCL-593 (Impact site CA-SCL-593 (Impact 593 (Impact CUL-1 and CUL-1 and CUL-2) CUL-1 and CUL-2). CUL-1and CUL - CUL-2). Cultural Resources Potential adverse impacts Potential adverse impacts 2).Potential adverse Potential adverse impacts on unknown cultural on unknown cultural impacts on unknown on unknown cultural resources and human resources and human cultural resources and resources and human remains ( CUL-4) remains (CUL-2 and CUL- human remains (CUL-2 remains (CUL-2 and CUL- 4) and CUL-4) 4) CUL-A. Implement the CA-SCL-593 MOA      and HPMP CUL-B. Archaeological Monitoring and     Unanticipated Discovery Plan Significance Determination S / LM S / LM S / LM S / LM S / LM Before Mitigation / After Mitigation Potential to expose (-) No significant impacts (-) Potential to expose (+) Potential to expose (+) Potential to expose structures or engineered structures or structures or structures or slopes to adverse effects engineered slopes to engineered slopes to engineered slopes to from seismic ground adverse effects from adverse effects from adverse effects from Geology, Soils, and Mineral Resources shaking (GEO-1). Potential seismic ground seismic ground seismic ground for soil erosion or loss of shaking (GEO-1). shaking (GEO-1). shaking (GEO-1). topsoil (GEO-2) Potential for soil Potential for soil Potential for soil erosion or loss of erosion or loss of erosion or loss of topsoil (GEO-2) topsoil (GEO-2) topsoil (GEO-2) GEO-A. Implement Geotechnical     Recommendations viii Upper Berryessa Creek Flood Risk Management Project ES- Tetra Tech Final Environmental Impact Report January 2016

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