SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT Final ENVIRONMENTAL ASSESSMENT And MITIGATED NEGATIVE DECLARATION

Prepared by:

U.S. Army Corps of Engineers Los Angeles District

With Technical Assistance Provided by:

Aspen Environmental Group Agoura Hills, California (Contract No. GS-10F-0229N)

August 2009

 

FINAL ENVIRONMENTAL ASSESSMENT AND MITIGATED NEGATIVE DECLARATION FOR THE SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT

1.

INTRODUCTION 1.1 Scope of the Environmental Assessment ............................................................ 1-1 1.2 Project Summary and Background ................................................................... 1-2 1.3 Purpose and Need for the Proposed Action ......................................................... 1-9 1.4 Agencies Expected to Use this EA/MND…………………………………………………………1-10 1.5 Authorization ............................................................................................1-11

2.

DESCRIPTION OF PROPOSED ACTION AND ALTERNATIVES 2.1 Introduction .............................................................................................. 2-1 2.2 Alternatives Evaluated and Eliminated .............................................................. 2-2 2.3 Project Alternatives (Alternatives Considered for Environmental Analysis) .................. 2-4 2.4 Operation and Maintenance ...........................................................................2-19 2.5 Measures Incorporated in the Proposed Action to Reduce Environmental Impacts .........2-20 2.6 Comparison of Alternatives...........................................................................2-20

3.

AFFECTED ENVIRONMENT 3.1 Air Quality ............................................................................................... 3-1 3.2 Biological Resources .................................................................................... 3-5 3.3 Water Resources and Hydrology ....................................................................3-24 3.4 Earth Resources (Geology) ........................................................................... 3-27 3.5 Land Use.................................................................................................3-30 3.6 Aesthetics ................................................................................................3-30 3.7 Recreation ...............................................................................................3-31 3.8 Noise .....................................................................................................3-31 3.9 Socioeconomics .........................................................................................3-35 3.10 Transportation ..........................................................................................3-36 3.11 Hazardous Materials and Waste Handling and Disposal ........................................3-37 3.12 Safety ...........................................................................................3-38 3.13 Cultural Resources .....................................................................................3-39 3.14 Public Services and Utilities .......................................................................... 3-43

4.

ENVIRONMENTAL CONSEQUENCES 4.1 Air Quality ............................................................................................... 4-1 4.2 Biological Resources .................................................................................... 4-9 4.3 Water Resources and Hydrology ....................................................................4-40 4.4 Earth Resources (Geology) ........................................................................... 4-47 4.5 Land Use.................................................................................................4-50 4.6 Aesthetics ................................................................................................4-54 4.7 Recreation ...............................................................................................4-57 4.8 Noise .....................................................................................................4-59 4.9 Socioeconomics .........................................................................................4-67 4.10 Transportation ..........................................................................................4-69 4.11 Hazardous Materials and Waste Handling and Disposal .........................................4-72

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FINAL ENVIRONMENTAL ASSESSMENT AND MITIGATED NEGATIVE DECLARATION FOR THE SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT

4.12 Safety .....................................................................................................4-76 4.13 Cultural Resources .....................................................................................4-78 4.14 Public Services and Utilities .......................................................................... 4-82 5.

CUMULATIVE IMPACTS ....................................................................................... 5-1

6.

GROWTH-INDUCING IMPACTS ............................................................................... 6-1

7.

ENVIRONMENTAL COMMITMENTS ......................................................................... 7-1

8.

COMPLIANCE WITH ENVIRONMENTAL REQUIREMENTS ............................................... 8-1

9.

AGENCY COORDINATION ..................................................................................... 9-1

10. LIST OF PREPARERS AND REVIEWERS ................................................................... 10-1 11. DISTRIBUTION LIST.......................................................................................... 11-1 12. REFERENCES ...................................................................................................12-1 13. LIST OF ACRONYMS AND ABBREVIATIONS ...............................................................13-1 APPENDICES A. Air Quality Calculations B. General Conformity Status Report C. 404(b)(1) Evaluation D. Response to Comments E. Initial Study F. Mitigation Monitoring Plan G. Mitigation Monitoring Plan for Biological Resources H. Jurisdictional Delineation

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FINAL ENVIRONMENTAL ASSESSMENT AND MITIGATED NEGATIVE DECLARATION FOR THE SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT

LIST OF TABLES 1.4-1 2-1 3.1-1 3.1-2 3.1-3 3.1-4 3.2-1 3.2-2 3.2-3 3.2-4 3.8-1 3.8-2

Agencies Expected to Use this EA/MND .................................................................. 1-11 Comparison of Alternatives ................................................................................... 2-23 Santa Maria Monthly Average Temperatures and Precipitation ................................... 3-1 National and California Ambient Air Quality Standards ............................................. 3-2 Attainment Status for the South-Central Coast Air Basin ............................................ 3-2 Air Quality Monitoring Summary 2003-2005 ......................................................... 3-3 Vegetation Habitat and Other Non-Habitat Elements ............................................... 3-10 Plant Species Observed within the Santa Maria Levee Project Area .............................3-12 Total Acreage of Jurisdictional Waters in the Santa Maria River Levee Project Area ........3-15 Wildlife Species Observed Within or Adjacent to the Santa Maria River Levee ..............3-16 EPA Designated Noise Safety Levels ..................................................................3-33 Land Use Compatibility for Community Noise Environment Local Regulations and Standards ...................................................................................................3-34 3.10-1 Average Daily Traffic on Selected Roadways in the Proposed Project Area ....................3-37 3.14-1 Utility and Service Providers by Jurisdiction .........................................................3-44 4.1-1 Estimated Project Construction Emission for the Proposed Action ................................ 4-4 4.1-2 Proposed Project Emissions/General Conformity Emissions Threshold Comparison........... 4-4 4.1-3 Estimated Project Construction Emission for the Sheet Pile Alternative (Mitigated) ........... 4-7 4.2-1 Vegetation, Habitat and Other Non-Habitat Elements Proposed Action .........................4-10 4.2-2 Total Acreage of Native Plant Communities by Classification ....................................4-13 4.2-3 Jurisdictional Features for the Proposed Project .....................................................4-17 4.2-4 Vegetation, Habitat and Other Non Habitat Elements Soil Cement Alternative ................4-32 4.2-5 Jurisdictional Features Soil Cement Alternative .....................................................4-36 4.5-1 Consistency with Applicable Land Use Plans and Policies .........................................4-51 4.8-1 Noise Emission Characteristics of Construction Equipment .......................................4-61 5-1 Cumulative Projects in the Proposed Project Activity Area ......................................... 5-1 5-2 Estimated Project Construction GHG Emissions for the Proposed Action (metric ton) ........ 5-5 8-1 Permissible Noise Exposures ............................................................................. 8-6

LIST OF FIGURES 1-1 1-2 2-1 2-2 2-3 2-4 2-5 2-6

Project Location Map ...................................................................................... 1-5 Timeline of the Damages Incurred ...................................................................... 1-8 Reach 1 ...................................................................................................... 2-7 Reach 2 ...................................................................................................... 2-8 Reach 3 ...................................................................................................... 2-9 Typical Cross Section of Sheet Pile Alternative..................................................... 2-11 Typical Cross Section of Soil Cement Alternative .................................................. 2-12 Existing Groins located in Project Area .............................................................. 2-15

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1. INTRODUCTION 1.1

SCOPE OF THE ENVIRONMENTAL ASSESSMENT

This document is a Final Environmental Assessment (EA)/Mitigated Negative Declaration (MND) for a levee improvement project proposed for the Santa Maria River located in Santa Barbara and San Luis Obispo Counties, California. It provides the required National Environmental Policy Act (NEPA) and California Environmental Quality Act (CEQA) documentation for the Proposed Action (42 United States Code [U.S.C.] §§ 4321 et seq.; California Public Resources Code [PRC] 21000 et seq.). This Final EA/MND has been prepared, specifically, to assess potential environmental impacts and benefits associated with the proposed Santa Maria Levee Improvement Project (Project) and feasible alternatives. The proposed Project would be constructed by the U.S. Army Corps of Engineers (Corps), and would utilize federal funding for the repair of an existing levee. Per NEPA regulations (Council of Environmental Quality (CEQ) Sec. 1501.2 and 1501.3), when Federal funding and/or land is involved, the Federal lead agency should prepare an environmental document to comply with NEPA. Therefore, the Draft EA was prepared in compliance with NEPA. The Draft EA was released for a 30day public review period and Notice was filed with the State Clearinghouse. An Initial Study (Appendix E) has been prepared in compliance with the CEQA for use by State Agencies to issue applicable permits. A section on growth inducement and a detailed Mitigation Monitoring Plan (Specifically for Biological Resources) have been included in the Final EA/MND. As per CEQA Guidelines [California Code of Regulations (CCR) Title 14, Chapter 3, Section 15225] “the Lead Agency under CEQA may use the federal document in the place of an EIR or Negative Declaration without recirculating the federal document for public review. One review and comment period is enough. Prior to using the federal document in this situation, the Lead Agency shall give notice that it will use the federal document in the place of an EIR or Negative Declaration and that it believes that the federal document meets the requirements of CEQA”. Additionally, CEQA Guidelines [CCR Title 14, Chapter 3, Section 15063] state that “the lead agency may use an environmental assessment or a similar analysis prepared pursuant to the National Environmental Policy Act” to satisfy the requirements of the CEQA document to issue required permits. An Initial Study Checklist (Appendix E) has been prepared to aid and facilitate evaluation of the proposed Project. The California Water Quality Control Board would use this Final EA/MND to issue a Water Quality Certification for the project construction. This Final EA/MND has been prepared in accordance with the requirements of the NEPA (42 U.S.C. §§ 4321 et seq.), in conformance with the CEQ Regulations [40 C.F.R. §§ 1500 et seq.], and guidance specified in Engineer Regulation (ER)-200-2-2 Procedures for Implementing NEPA. The document also fulfills the requirements of the CEQA (California PRC 21000 et seq.), and the State CEQA Guidelines (CCR 15000 et seq.). The Santa Maria River Levee project was originally constructed in 1963 by the Corps. It consisted of a set of earthen levees with riprap revetment. The levee along the south side of the river extends a

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 1. Introduction

distance of about 17 miles, begins at Fugler’s Point, and ends at the California Highway 1 (CA-1) bridge. This project also includes a 5-mile long levee along the north side of the river, located between the U.S. Highway 101 Bridge and the California Highway 1 Bridge. The levee project provides flood protection to the Santa Maria Valley which includes the entire city of Santa Maria. In 2005, the Federal Emergency Management Agency (FEMA), responsible for administering the National Flood Insurance Program, requested the Corps to certify that the Santa Maria Levee Project meets the Corps criteria for levee systems. Based on hydraulic and geotechnical analysis and review of several documented failures, the Corps is not able to certify that the levee system will contain a 1% flow event1 and satisfy the legal requirements set forth in the Code of Federal Regulations, National Flood Insurance Program (November 2008, Article 44, Section 65.10, Mapping of Areas Protected By Levee Systems). The Corps has identified a deficiency in the original levee design, which does not account for the angle of approach of meandering, lower volume flows that impinge on the levee. As an example, approximately three years following original construction of the levee, the levee was almost breached in two locations during a moderate flood event (i.e., estimated at 30,000 cubic feet per second (cfs)) because flows along the meandering low flow channel impinged on the levee at a nearly perpendicular angle. The levee revetment was designed to handle 150,000 cfs in bank to bank flow (i.e., flow path parallel to the levee system), but did not address the potential for failure resulting from directly impinging flows. Following an extensive alternatives analysis, the Corps has chosen to strengthen an approximate 6.5 mile reach of the existing south levee with sheet pile and soil cement revetment in order to address this deficiency. As currently designed, soil cement would be applied to the levee face and levee toe along the majority of the proposed Project reach (approximately 6.2 miles), and would transition to sheet pile for the remaining 1,700 feet of the Project area (the upstream extent of the Project area at Bradley Canyon). Please see Section 2 for details on Alternatives analyzed for the Project. The Corps has prepared a Design Deficiency Report (DDR) to document the design deficiency investigation, alternatives to correct the deficiency, and to recommend a corrective action that will resolve the deficiency. The DDR is on file at the Corps, Los Angeles District Office. 1.2

PROJECT SUMMARY AND BACKGROUND

1.2.1

Project Location and Vicinity

The proposed Project site is located in the city of Santa Maria, Counties of Santa Barbara and San Luis Obispo, California (Figure 1-1, at the end of this chapter). The proposed Project consists of improving a 6.5-mile reach of the southern Santa Maria River Levee, extending from the terminus of Bradley Canyon to the north end of Blosser Road (Figure 1-1). The Santa Maria River originates in the Los Padres National Forest and drains a 1,880 square mile watershed. It is rocky and shallow, and consists of a very wide flat channel bordered by the Santa

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 1. Introduction

Maria River Levee along portions of the north and south banks to protect farms, and the city of Santa Maria. The river defines part of the border between Santa Barbara County and San Luis Obispo County, California and empties into the Pacific Ocean. No lakes or dams are located on the Santa Maria River and during much of the year it has very little water, but can swell greatly during a winter storm. Adjacent land uses include residential, commercial, agricultural, recreational, and industrial (Figure 11). The proposed Project site is bordered by urban development within the city of Santa Maria to the southwest and the Santa Maria River to the northeast. Urban development includes a bikepath with a safety rail along the top of the levee, residential neighborhoods, a concrete company, and the Santa Maria Landfill. Agricultural land and undeveloped property are located north of the proposed Project site and across the Santa Maria River. The levee and proposed Project site are traversed by the United States Highway 101 (US-101) bridge overpass and Suey Road. Existing structures within the study area include the above mentioned crossings, the levee itself, rocks along the levee face, soil cement and rock groins, metal training fence, station markers, an irrigation pipe and wire revetment. The proposed Project area consists of the levee and adjacent river bed. The top of the levee is approximately eight feet above the river bed, which is generally level. Stormwater and urban runoff drainage within the urban areas to the south and west (city of Santa Maria) flows towards the river, and drains into the riverbed via floodgates that traverse the levee. Flow within the river is generally confined within the levee system, but during moderate to large events flows may spread into unprotected agricultural property and/or breach the levee itself. Habitat communities within the proposed Project area include riparian scrub, non-native grassland, coastal sage scrub, ruderal/disturbed, riverwash, eucalyptus woodland, freshwater marsh, and landscaped/developed vegetation. 1.2.2

Site History

The Santa Maria River is formed by the confluence of the Sisquoc and Cuyama Rivers. The Santa Maria River Watershed is approximately 1,880 square miles, making it one of the largest coastal drainage basins in California (CRWQCB-CCR, 2008). It is estimated that the Santa Maria aquifer is up to 8 miles wide and underlies approximately 110,000 acres of the basin. In general, the majority of the river is dry throughout most of the year, then will flow episodically during rain events (e.g., during winter storms). Before the building of the Twitchell Dam, the Santa Maria River likely flowed continuously for much of the year. The perennial water source and rich alluvial soils led to an extensive agricultural boom, dating back to the 1800s and continuing to present day. The riverbed within the Project reach is composed of mainly sandy loamy soils and due to soil type, hydrologic input, and gradient, is comprised of rapidly changing morphologies. Before the dense urban development present today, the river and surrounding areas undoubtedly supported more mature, dense riparian habitat and numerous wildlife species. Various nesting and migratory birds historically relied on the riparian habitat created by this immense water source.

1

The 1% flood, also referred to as the “100-year flood”, is of the magnitude which has a 1% chance of being equaled or exceeded in any one-year time period.

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 1. Introduction

Constructed Levee System: The constructed Santa Maria River Levee Project consists of a set of earthen levees with riprap revetment along the river-side slope. The south levee extends a distance of approximately 17 miles along the south side of the River, beginning at Fugler’s Point, (immediately downstream of the confluence of the Cuyama River and the Sisquoc River) and ending at the State Highway 1 bridge in Guadalupe. The constructed levee project also includes a 5-mile long levee along the north side of the river. This levee extends from a point approximately 1.4 miles downstream of the US-101 Bridge to a point approximately 1.9 miles upstream of the State Highway 1 (CA-1) bridge. Construction began in 1959 and was completed in 1963. The levee project was designed to contain the standard project flood (SPF). The design discharges were 160,000 cfs from the project inlet at the confluence of the Cuyama River and Sisquoc River to the confluence with Suey Creek; 155,000 cfs from Suey Creek to the end of the double levees; and 150,000 cfs from the end of the double levees to the downstream end of the project at CA-1. Quarried stone was selected as the levee and toe revetment. The levee side slopes were set at two horizontal to one vertical. Construction of the levee project was completed in June 1963. The December 1966 flood, which was approximately one-fifth the magnitude of the project-design flood, caused some damage to the levee. The original [channel bottom] grade was about 11.5 feet below the top of the levee. After the flood, the grade was about 15 feet below the top of the levee. The damaged levee was repaired by the Santa Barbara County Flood Control and Water Conservation District (SBCFCWCD), which also excavated a pilot channel to divert flood flows away from the left levee.

December 1966 Flood

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 1. Introduction Southern California Region

Reach 1 15

KERN

Batch Plant 2

SANTA BARBARA

40

15

VENTURA 5

101

Batch Plant 1

395

LOS ANGELES SAN BERNARDINO

Los Angeles

Staging/Stockpile Area

Project Area

San Luis Obispo Co. Rd .

N

Bu ll C an yo n

RIVERSIDE

ORANGE

10

Santa Ana 5

SAN DIEGO IMPERIAL

15

San Diego 8

No Scale

W. Taylor St.

N. Broadway

N. Railroad Ave.

Reach 2

N. Blosser Rd.

Long Beach

Legend Project Area County Boundary City Boundary

Suey Rd.

E. Donovan Rd.

Borrow Area

SANTA MARIA E. Alvin Rd.

Reach 3 101

Staging/Stockpile Area

Main St.

Santa Barbara Co.

N

PREPARED BY

Batch Plant 3 / Staging/ Stockpile

Aspen

Environmental Group

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0

4,000

Figure 1-1 Project Location Map

8,000

Scale in Feet

1-5 1-9

August 2009

 

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 1. Introduction

During the February 1969 flood, several problem areas developed as a result of several days of sustained flows. At these select locations, flood flows had stripped the facing stone from the levee, leaving only a deteriorated impervious filter blanket. A secondary levee was built behind the severely eroded sections and large derrick stones were placed to protect the damaged levee. Additional repairs included a pilot channel along the entire length of the project, additional scour gages, as well as groins, retarding fences, and/or additional toe protection, at those locations where past damage had occurred.

Emergency Repair for 1969 Flood Damage

During the February 1980 flood, damage resulted at select location(s) from meandering low flows hitting the levee at about an 80 degree angle. The levee sloughed off in a crescent shape until it reached a point about 4 feet from the edge of the levee road. Approximately 200 feet of levee facing was replaced with about 600,000 tons of rock. Please see Section 1.2.3 below for a description of the repairs and levee as it presently exists. Despite the construction of groins and training fences performed by the SBCFCWCD, severe flood damage occurred in February 1998. Damage resulted in a breach approximately 600 ft long located on the right (north) levee approximately 500 ft downstream of Bonita School Road. A representative from the SBCFCWCD indicated that overbank flow had eroded the toe of the levee along the land side. The levee breach and other damaged areas were repaired to the original as-constructed conditions, and no additional project modifications were made. In 2005, during an event that yielded approximately 8,000 cfs in the low flow channel, an area of the riverbed adjacent to the groins and levee toe was scoured. This damage required a flood fighting response by the SBCFCWCD. This event indicated that the effectiveness of the groins may be limited in providing protection against cross channel flows that impinge on the levee between the groins.

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 1. Introduction

As shown in Figure 1-2, over the last 44 years the annual peak discharge on the Sisquoc River has exceeded 8,000 cfs twelve times or once every 3.7-years. Seventy-five percent of the time that the peak discharge exceeded 8,000 cfs the levee suffered significant damage, nearly breached, or actually breached. The maximum flow during this period is less than 35,000 cfs, which is less than 25% of design capacity.

Figure 1-2. Timeline of the Damages Incurred

1.2.3

Existing Levee Description

Following flood damage in February 1980, a series of repairs were made to the Santa Maria River Levee Project. Other than the emergency post-flood repairs (described in Section 1.2.2) completed between 1963 and 1980, the levee exists today with the following upgrades from the original design (described in Section 1.2.2): •

An extension of a pre-existing training fence on the left (south) side at Fugler Point.

•

A series of segmented double training fences on the right (north) side of the river just upstream of the Bradley Canyon confluence.

•

A total of 94 groins at three locations along the left (south) levee and one along the right (north) levee.

•

A double pole and wire training fence filled with rock approximately 2,000 feet long extending downstream from the downstream end of the right (north) levee.

•

Seventeen additional scour gages and development of a streambed monitoring program.

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 1. Introduction

1.3

PURPOSE AND NEED FOR THE PROPOSED ACTION

Section 1.2.2 provides brief history of flooding along the Santa Maria River. An analysis of the levee system in 1996 concluded that the current levee system (and in particular the rock revetment) did not meet the original design criteria at certain locations, and does not meet the current rip rap protection criteria at many locations. The Corps has identified a deficiency in the original levee design, which does not account for the angle of approach of meandering, lower volume flows that impinge on the levee. The performance history of the levee system (described in Section 1.2.2) highlights the continuing impact of this deficiency in the original design. Based on analysis and review of several documented failures, the Corps couldn’t prove that the levee system will contain a 1% chance of exceedance flow event and satisfy the legal requirements set forth in the Code of Federal Regulations, National Flood Insurance Program (November 2008, Article 44, Section 65.10, Mapping of Areas Protected By Levee Systems). Accordingly, FEMA is currently revising its flood insurance maps with the assumption that the levee project no longer offers adequate protection to the city of Santa Maria. As identified in the DDR over the last 44 years the annual peak discharge on the Sisquoc River has exceeded 8,000 cfs twelve times or once every 3.7 years. Seventy-five percent of the time that the peak discharge exceeded 8,000 cfs the levee suffered significant damage, nearly breached, or actually breached. The maximum flow during this period is less than 35,000 cfs, which is less than 25% of design capacity. A review of the levee system’s past performance clearly indicates that without a rapid and comprehensive flood control response, another breach of the levee is likely in the future. A complete breach in the levee would produce devastating impacts to the surrounding community, including several schools and several hundred homes, producing an unacceptable risk to life and property. In its present condition with only about a fourth of the project protected from undermining with additional features, the subject levee project is vulnerable to breaching from relatively frequent floods along most of its length. Therefore, there is a need to repair the existing levee to prevent a breach from future flooding. The purpose of the Proposed Action is to address the original design deficiency by repairing a 6.5-milelong section of the levee to contain a 1 percent change of exceedence flow and reduce the risks to life and property. With the construction of levee repairs, the risk of flooding to the local community would be significantly reduced. Without the recommended corrective action detailed in this report, a levee breach failure is a near certainty. The exact failure location could never be known before it occurred, but, if Reach 1, 2, and 3 were constructed, the residents of the city of Santa Maria would be protected to the level described. As was stated at the beginning of this report, the Federal Government has the responsibility to correct this deficiency and provide the residents of Santa Maria the flood risk reduction they were promised by Congress in 1954.

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 1. Introduction

In order to address the original design deficiency and reduce the risk to life and property, the Corps proposes to strengthen the existing south levee with sheet pile and soil cement revetment. As currently designed, soil cement would be applied to the levee face and levee toe along the majority of the proposed Project reach (approximately 6.2 miles), and would transition to sheet pile for the remaining 1,700 feet of the Project area (the upstream extent of the Project area at Bradley Canyon). This Final EA/MND has been prepared, specifically, to assess potential environmental impacts and benefits associated with the proposed Project and feasible alternatives. 1.4

AGENCIES EXPECTED TO USE THIS EA/MND

The Corps is the Lead Agency for evaluating potential impacts and proposing mitigation measures under the NEPA and CEQA laws, respectively. The Draft EA was provided to the concerned resource agencies including but not limited to the Environmental Protection Agency (USEPA), U.S Fish &Wildlife Service (USFWS), California Department of Fish and Game (CDFG) and California Regional Water Quality Control Board (CRWQCB). Several other agencies have special roles with respect to the Proposed Action and my use this EA/MND as the basis for their decision to issue any approvals and/or permits that might be required. Table 1.4-1 lists lead agency and federal, state and local agencies that may rely on this EA/MND in review capacity or as a basis for issuance of permits for the Proposed Action or for related Action. Agency Federal Agencies U.S. Army Corps of Engineers U.S. Fish and Wildlife Service U.S. Environmental Protection Agency State Agencies California Department of Fish and Game Regional Water Quality Control Board, Central Coast Region Regional Agencies South Central Coast Air Basin Local Public Agency Santa Barbara County Flood Control District

Final EA/MND

Table 1.4-1 Agencies Expected to Use this EA/MND Responsibilities, Permits, and Approvals

Lead federal agency for the proposed levee improvement project. The Corps (Regulatory Division) has permitting authority under Section 404 of the Clean Water Act, Section 10 of the Rivers and Harbors Act to issue Section 404 permit to the local-sponsor for the future maintenance. Reviews and submits recommendations to USACE related to federal construction actions and if needed issuance of permits in accordance with the Fish and Wildlife Coordination Act and consultation pursuant to Section 7 of the Endangered Species Act (ESA). Has primary responsibility for implementing the Clean Air Act (CAA) and works with other federal agencies to implement conformity requirements. The proposed project does not exceed the Federal Standards for any pollutant; therefore, a RONA has been prepared to comply with General Conformity Rule. Reviews and submits recommendations in accordance with CEQA. Federal agency is exempt from obtaining 1601 Streambed Alteration Agreement. Permitting authority for waste discharge requirements for discharges that might affect groundwater, Section 401 Water Quality Certifications, and National Pollutant Discharge Elimination System (NPDES) permit for discharge of wastewater into surface waters. The RWQCB will use this document to issue Section 401 permit. Permitting authority over stationary and area sources for approving emissions from construction and operation of emission-producing equipment, and for regulating air toxics and other air quality nuisance sources. Any construction equipment needs permit, the Construction Contractor would obtain required permits. The Santa Barbara County Flood Control District would be responsible for maintaining the constructed project for the life of the project. They will use this EA/MND to obtain any necessary permits including but not limited to Section 404 Corps Regulatory Permit, Section 401 Water Quality Certification to implement future maintenance of the project. The Corps will develop a revised maintenance manual, which would include all environmental commitments/mitigation measures that should be followed by Santa Barbara County.

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 1. Introduction

1. 5

AUTHORIZATION

The flood control improvements in the Santa Maria River Basin, California, as set forth in House Document 400, Eighty-third Congress, second session, was approved 3 September 1954 by Act of Congress, Public Law 780, Eighty-third Congress, second session. Based on the criteria in ER 1165-2119 (Modifications to Completed Projects), the construction required for this federal Proposed Action is authorized under the existing project authority from 1954. This study is authorized under Public Law 91-190, NEPA of 1969, as amended; Engineer Regulation (ER) 200-2-2, Procedures for Implementing NEPA; Public Law 93-205, Endangered Species Act (ESA) of 1973 (c) (4); and Public Law 95-217, of the Clean Water Act (CWA) of 1977, as amended. In accordance with Section 1.06 of the Operation and Maintenance Manual for Santa Maria Valley Levees and Channel Improvements, the Santa Barbara County Flood Control and Water Conservation District is responsible for the operation and maintenance of completed flood control levees and channel improvements.

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2. PROPOSED ACTION AND ALTERNATIVES 2.1

INTRODUCTION

The Federal Emergency Management Agency (FEMA) requested the US Army Corps of Engineers (Corps), Los Angeles District (LAD), to certify the Santa Maria River Levee Project originally constructed in 1963. After researching several historical reports and investigations into previous failures, and analyzing the levee system from geotechnical and hydraulic standpoints, the Corps LAD is not able to certify with reasonable certainty that this levee system will contain the 100-year flood (or 1% chance of exceedence) flow event. FEMA is currently revising its flood insurance maps with the assumption that the levee project no longer offers any protection to the city of Santa Maria. As stated in Engineer Regulation (ER) 1165-2-119, it is a general policy of the Chief of Engineers that completed Corps projects be observed and monitored by the Corps to ascertain whether they continue to function in a satisfactory manner and whether potential exists for better serving the public interest. While, generally, significant modifications to existing projects require authorization by Congress, occasionally a project may deserve modification because its original development was inherently deficient. Therefore, the Corps LAD initiated an examination of the design of the levees constructed in 1963 along the Santa Maria River. As identified in Section 1 of this Final EA/MND, the investigation revealed that the project must be corrected to avoid the potentially catastrophic consequences of a levee breach. Over the last four decades, there have been several remedial construction efforts undertaken on this levee or within the river bed. These efforts have attempted to compensate for the underlying deficiency, but each has proven to be either limited in effectiveness or temporary. The Design Deficiency Report (DDR) for the Santa Maria Levee River project prepared by the Corps LAD identifies the past history of flooding as well as an examination of various Alternatives to repair the levee to prevent breaching of the levee in the future and to meet the standards/criteria identified in ER 1165-2-119 (the DDR is on file at the Corps LAD office in Los Angeles). The DDR describes details on development of the Alternatives to repair the existing levees. From technical point of view, six preliminary Alternatives were initially considered feasible. These preliminary alternatives included: 1) sheet pile wall; 2) soil cement; 3) riprap; 4) articulated concrete block; 5) gabion mattresses; and 6) jet grouting. During plan formulation, geotechnical conditions were examined which included faulting, subsurface conditions, groundwater conditions, seismicity and strong ground motion, land sliding and slope stability, surface fault rupture, flooding, tsunamis and inundation, and scour and erosion. Hydraulic design considerations included examination of the initial design of the original project, performance of the groins, scouring along the levee, and flood flow. Further environmental factors were considered in the refinement of the alternatives. Details related to plan formulation (geotechnical and hydraulic design consideration/examination) are provided in the DDR (August 2009). Section 2.3 identifies alternatives carried forward for analysis of environmental impacts.

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2.2

ALTERNATIVES EVALUATED AND ELIMINATED

Jet Grouting – Jet Grouting is a versatile ground modification system used to create in-situ cemented geometries of soilcrete. Ultra high-pressure binders (water cement mixture) would be injected into the core of the levee at high velocities. This water cement mixture would break up the soil structure completely and mix the soil particles in-situ to create a homogeneous, cylindrical mass, which would solidify. These cylindrical masses would then be overlapped to create a linear curtain of soilcrete which would resist scour and thereby protect the levee. Jet grouting is very costly and requires specialized equipment. Because of the erosion caused by directly impinging flows, a very large zone of soilcrete would be required within the levee for this alternative to perform well. Once the levee was in the eroded condition, this mass of soilcrete would need to be designed to act as a gravity wall. This would preclude the use of just one linear curtain of soilcrete. There would need to be overlapping linear curtains of soilcrete to gain the mass required for a gravity wall. Because the scour depth from the top of the levee would be potentially 30 feet, there would likely be several overlapping linear curtains of soilcrete. The magnitude of soilcrete required makes this alternative impracticable. Additionally, once the overlying soil is eroded, the exposed concrete face would present a public safety hazard until maintenance crews rebuilt the eroded levee. During heavy flood event implementation of this Alternative would cause increase impacts to the Waters of the U.S by scouring and eroded material. Repeated repair at multiple locations would result in disturbing larger footprint compare to the Proposed Alternative, and cumulatively it would cause greater impacts to the Waters of the U.S. This Alternative does not meet the project purpose. Therefore, in light of these factors, this measure was not recommended for further analysis. Gabion Mattresses – Gabions are wire fabric containers that interconnect with other similar containers and are filled with on-site stone to form monolithic structures. The rock that fills these mattresses is typically smaller than what would be required for riprap. These mattresses would be laid end to end and side to side on the prepared levee bank to form a continuous mattress. This continuous mattress would resist scour and thereby protect the levee. Practical application of this erosion control method is generally limited to areas with intermittent flows and small drainage areas. Using gabions to solve the design deficiency in this project is not practicable due to the presence of impinging flows. The biggest concern is that the wire would most likely break due to abrasion and corrosion after several years. Once the wire fabric breaks, the only scour protection would be the small stone that was in the wire fabric containers. This rock is smaller than what would be required for riprap and would be washed away during storm events. This would leave the levee vulnerable to erosion and failure at locations where the wire has been damaged. In order to repair damaged gabions, the old section must be completely removed and new units installed. This action is labor intensive and would require work to be completed in the river channel. For these reasons, it was concluded that Gabion Mattresses would not meet the project purpose. In addition, depending on the scale of the damage, repair and would likely result in continued long term effects to

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Waters of the U.S. Another disadvantage to this Alternative is that local river rock is not suitable for use in the gabions. Use of this Alternative would require the importation of suitable rock from on offsite source greatly increasing costs and air emissions. Therefore, this measure was not considered for further analysis. Riprap – This is the revetment method currently used on the levee which has proven unsuccessful at containing major storm flows. This alternative would involve placing an additional layer of suitably large rock over the existing layer of riprap for the full height of the levee from the top down to the design scour depth. This new layer of riprap would have to be large enough to withstand the erosive forces caused by impinging flows along the meandering low flow channel. This new structure would resist the scour and thereby protect the levee. Required riprap stone size is usually determined by the velocity of the flow parallel to the levee face. However, there are no adequate hydraulic design criteria currently available to reliably determine the size and layer thickness of the riprap necessary to withstand the highly erosive forces caused by impinging flow conditions. Even though the new riprap must be substantially larger than the existing stone, determining the required stone size is very difficult. As shown by the degradation of the existing stone, it is very difficult to obtain quality stone in the project area. Obtaining large, quality stone would require long haul distances that would increase the construction cost of the project. In addition, this Alternative would increase the traffic and air quality impacts caused by trucks importing the stone from off-site sources. Because of the lack of adequate design criteria and the difficulty in obtaining quality stone near the project, this alternative is technically impracticable. Therefore, this measure was not considered for further analysis. This Alternative does not meet the purpose of repairing the levee to contain a 1% chance of exceedance flow during a flooding event. In addition, the large scale footprint of the project and potential repairs required would result in cumulatively larger impacts to waters of the U.S. In addition, the transportation of rock would require many truck trips which would result in significant impacts to traffic and air quality. Therefore, this measure was not considered for further analysis. Articulated Concrete Block – Articulated concrete block is an interlocking matrix of concrete blocks of uniform size, shape and weight connected by a series of cables which pass through pre-formed ducts in each block. These interlocking blocks form an erosion resistant mattress that would be placed on the levee slope for the full height of the levee from the top down to the design scour depth. This matrix of connected blocks would resist the scour and thereby protect the levee. Importing the number of articulated concrete blocks needed for the project would require many trucks which would increase traffic and air quality impacts. This product is not as effective as riprap in adjusting to erosion of underlying sandy soil due to its somewhat limited flexibility. In fact, failures have been observed where a corner or edge of the articulated concrete block mattress was undercut and there was an unraveling effect causing the failure of the whole revetment. Because of the impinging flows conditions, a major concern is that the erosive forces from these flows will cause a failure of the

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mattress by eroding the underlying sandy soil and that the subsequent flows will undermine and strip off large sections of the revetment. Because of the impinging flow failure mode occurring on this project, the use of this engineering product can not be definitively determined to be technically practicable. Therefore, this measure was not considered for further analysis. The Engineering Division has indicated that this material would not be sufficiently resistant to the storm flows expected to occur in the Santa Maria River and would require increased maintenance. Therefore, it does not meet the project purpose to contain a 1% chance of exceedance flow during flooding event and was not considered for further analysis. PROJECT ALTERNATIVES (ALTERNATIVES CONSIDERED FOR ENVIRONMENTAL ANALYSIS)

2.3

Four alternatives have been carried forward for detailed analysis in this EA, including the No Action Alternative. These alternatives are: •

No Action Alternative

•

Sheet Pile and Soil Cement Alternative (Proposed Action)

•

Sheet Pile Alternative

•

Soil Cement Alternative

The two revetment alternatives initially evaluated and refined in the DDR were sheet pile and soil cement. During development of this EA/MND, a third action alternative was identified that would help avoid and minimize environmental impacts, including impacts to Federally listed species, at the upstream end of the project area. This third alternative, which would involve a combination of sheet pile and soil cement and is referred to herein as the Sheet Pile and Soil Cement Alternative, has also been carried forward for analysis. 2.3.1

No Action Alternative

Under the No Action Alternative, no Federal participation from the Corps to provide additional flood risk management to the study area would occur. The “future without-project” condition of increased risk of continued breaches in the levee and resulting flood hazards would be present. This could result in the occurrence of continued breaches, with resulting flood flows that could produce devastating impacts to the surrounding community, including significant loss of life of individuals residing within the city of Santa Maria. The No Action Alternative would be inconsistent with the city of Santa Maria Safety Element, the county of San Luis Obispo and the county of Santa Barbara Seismic Safety and Safety Elements, which call for the maintenance of flood control facilities to ensure adequate capacity. Additionally, the viability of existing and planned land uses would not be consistent with land use policies identified in the General Plans of the city of Santa Maria, San Luis Obispo County, and Santa Barbara County.

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If no action occurs, the Santa Barbara County Flood Control and Water Conservation District (SBCFCWCD) may implement the following action plan during the flood season: 1) Ongoing annual routine maintenance to construct and/or maintain pilot channels within the Santa Maria River to direct frequently occurring low flows away from the levee at the locations of greatest concern, 2) stockpiling large rock for flood fighting at key locations immediately adjacent to the levee, and 3) developing a detailed flood fighting response plan. This action plan would provide immediate but temporary protection to the levee from the effects of meandering low flows and help facilitate timely and aggressive flood fighting of larger flows with sufficient quantities of large rock. Continuing ad-hoc maintenance to reduce risk of a levee breach would be more environmentally damaging than implementing the Proposed Action. 2.3.2

Proposed Action (Sheet Pile and Soil Cement)

This alternative would involve soil cement slope protection for most of the project length, combined with a segment of sheet pile 1700 feet long. Soil cement would extend from the downstream end of Reach 1 (north end of Blosser Road) (Figure 2-1), through Reach 2 (Figure 2-2), to approximately 6.2 miles to the upstream end of Reach 3 (Figure 2-3). At this point, the soil cement slope protection would transition to sheet pile for the remaining 1,700 feet of Reach 3 (the upstream extent of the Project area at Bradley Canyon). The three reaches of the Santa Maria River are described below (Figures 2-1 through 2-3): •

Reach 1 – Blosser Road to Highway 101 Bridge - STA 649+00 to STA 711+50 (~ 1.2 miles long)

•

Reach 2 – Highway 101 Bridge to Suey Crossing Bridge - STA 711+50 to STA 819+00 (~ 2.0 miles long)

•

Reach 3 – Suey Crossing Bridge to Bradley Canyon (STA 819+00 to STA 984+00) (~ 3.1 miles long)

In order of priority, Reach 2 is the most critical in terms of life safety. If a levee breach were to occur within this reach, it would have the most devastating effects. Using this as the decision criteria, construction of the new revetment is proposed within Reach 2 first, within Reach 1 second, and within Reach 3 third. Levee access points for this alternative include: (1) To the west end of Reach 1 via a gated entry from Blosser Road, (2) To the middle of Reach 2 via a gated entry ramp from the city street to the top of levee, (3) To the levee between Reach 2 and Reach 3 via two gated entries at the Suey Crossing Bridge, and (4) To the further upstream portion of Reach 3 via a gated entry at the east end of the active Santa Maria Regional Landfill, adjacent to the levee. A detailed description of the components of this alternative has been provided in the following paragraphs.

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2.3.2.1

Sheet Pile Portion of Proposed Action

Sheet pile walls consist of a series of panels with interlocking connections driven into the ground with impact or vibratory hammers to form an impermeable barrier. This method could be used without disturbing the existing levee. If the levee were to erode because of impinging flows, the steel sheet pile would form a wall that would prevent the breach of the levee. However, in this eroded condition, the steel sheet pile would have to have the strength necessary to act as a retaining wall. The sheet pile is designed based on the worst case condition. This design scour would expose the sheet pile for a vertical height of up to 30 feet. The sheet pile would be driven approximately 69 feet deep to ensure anchorage should the scour be that extreme (see Figure 2-4 below for typical cross-section). Tiebacks would be required at 10 feet intervals located near the top of the sheet piles. Due to the relatively narrow levee cross section, a screw type tieback anchor would be used. Figure 2-4 Typical Cross Section of Sheet Pile Component

Source: U.S. Army Corps of Engineers (USACE), Draft Design Deficiency Report for the Santa Maria Levee Project, December 2008.

Construction Process for Sheet Pile The sheet pile would be installed at the crest of the existing levee, requiring removal of the existing fence and station markers. The sheet pile wall would not extend above the existing grade. The embedment depth (up to 69 feet) is adequately deep to provide structural stability when the soil on the river side of the levee is eroded down to the estimated scour depth. After installation of the sheet pile wall, the levee crest would be resurfaced, and the fence and station markers would be replaced. Installation would not require removal of the existing rock slope. Next, tiebacks would be installed. Each tieback would be installed by drilling a hole a few feet from the top of the sheet pile, then drilling the screw type anchor back into the earth the necessary depth, and then tensioning the tieback by bolting it to the sheet pile. This bolted connection between the tiebacks and the sheet pile would be encapsulated within the concrete pile cap that would be cast in place at the top of the sheet pile.

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The top of the river side of the levee would require minimal excavation to provide access to install the tiebacks and concrete pile cap. No excavation would be required in the riverbed. Staging areas would be located on County or city of Santa Maria owned property outside the river channel. All construction work would be completed within the footprint of the SBCFCWCD-owned right of way. Additionally, groins and a training fence constructed for the original project along the levee would be demolished and disposed of. Please see details of the groins described below under the construction process for soil cement. Construction Equipment of Sheet Pile Construction equipment would include one pile driver, one bulldozer, three dump trucks, one hydraulic excavator, one track loader, three ready-mix concrete trucks, and one water truck. All construction equipment would be able to access the sheet pile operations from the maintenance road on top of the levee. Construction Route of Sheet Pile The proposed transportation route would utilize Blosser Road, Donovan Road, Main Street, and existing service roads adjacent to the levee (see Figure 1-1). 2.3.2.2

Soil Cement Portion of Proposed Action

Soil cement is a densely compacted mixture of cementitious material, soil aggregate and water. The mixture is compacted to form a hardened structure with specific engineering properties. Soil-cement is useful as a liner because the material has higher compressive strength and lower hydraulic conductivity than the non-cemented soil. The soil cement slope protection visually appears as a natural bank and is economically feasible. This alternative consists, essentially, of overlaying the original riprap revetment with a new continuous revetment of soil cement. Through excavation of the river bed immediately adjacent to the levee, the levee slope of two feet horizontal to one foot vertical (2H:1V) would extend down to the required scour depth (see Figure 2-5 below for typical cross-section). Figure 2-5 Typical Cross Section of Soil Cement Component

Source: USACE, Draft Design Deficiency Report for the Santa Maria Levee Project, December 2008.

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The existing riprap revetment would not be stripped off of the levee before the soil cement would be placed. Instead, soil cement would be placed against the existing riprap. The excavated material would be the source used to generate the soil cement for the new revetment. Once mixed in an on-site plant, the soil cement would be compacted in 1-foot-thick and 8-foot-wide layers. This operation would be repeated until the soil cement reaches the top of the levee. Once the soil cement is placed, the excavation would be backfilled with the material not used for the mixing of the soil cement. Because the volume of soil cement below the surface of the ground would reduce the volume of backfill needed, the backfill would only be a few inches shallower than the original riverbed elevation. After the necessary regrading, this would be undetectable. Construction Process for Soil Cement The construction process would include the following steps (see Figure 1-1 for locations of borrow, staging and batch plant areas): (1) excavating soil/sand on the riverward side of the levee borrow area; (2) stockpiling excavated soil at the staging area ; (3) excavating additional soil/sand from the river and trucking it to a portable batch plant; (4) mixing soil/sand with concrete to create soil cement at the portable batch plant; (5) trucking soil cement from the portable batch plant to the construction area; (6) benching the face of the exposed slope with soil cement; and (7) backfill soil/sand. This process is described in further detail below. A spill prevention and contingency plan, dewatering plan, and stormwater pollution prevention plan would be prepared by the Corps to reduce impacts to water resources/hydrology. Additionally, soil/sand excavation and construction within the river bed would not occur during the rainy season. Please see Environmental Commitments BR-6 through BR-8, and ER-1 and ER-2 in Section 7 for measures that will be incorporated to reduce impacts to water resources/hydrology and biological resources. Project construction, specifically clearing/grubbing dewatering and excavation activities would be monitored by environmental staff to ensure that commitments identified in the Final EA/MND, Section 401 Water Quality Certification and applicable permits are followed during construction. The Construction contractor would prepare a Storm Water Pollution Prevention Plan (SWPPP) to minimize erosion and impacts to water quality. The SWPPP would be reviewed by the Corps to ensure that appropriate measures are included. On the riverward side of the levee, soil would be excavated to a depth of approximately 25 feet, 80 feet from the toe of the levee, at a 2H:1V slope. Excavated soil would be stockpiled adjacent to the work area. A portable batch plant would be assembled to generate soil cement. There would be only one soil cement batch plant in operation at a time. The batch plant would be located within the 120-foot width construction zone within each Reach and moved as each construction reach is completed. Material (approximately 1,036,100 cubic yards) needed for the soil cement would be obtained through the necessary excavation at the toe of the levee. The SBCFCWCD conducted soil testing in March 2008 that indicated the in situ materials at the toe of the levee were suitable for soil cement.

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As part of this alternative, temporary construction of pilot channels may be required to direct flow away from the construction areas. The operator, SBCFCWCD, has excavated pilot channels within the Santa Maria River many times in the past in an effort to divert river flows away from the levee as part of their annual routine maintenance. Existing pilot channels would be used to the maximum extent feasible during construction to divert the flow from the construction area toward the center of the river channel. If pilot channel excavation is required, the excavated material may be used for construction of soil cement. Dimensions of the excavated pilot channels could be up to approximately 3,000 feet by 20 feet wide, with a 4 foot depth. Approximately 106,563 cubic yards of borrow material may be excavated from this low flow diversion channel and used to create soil cement. Temporary access routes to the excavation areas would be established within sandy areas inside the construction zone. Soil cement would be transported from the batch plant to each levee work area by bottom dump trucks. The existing rock slope would be covered by soil cement. The soil cement mixture would be benched out up the face of the exposed slope, spread by motor-grader and roller compacted to create a hard permanent surface once dry. The typical lifts of soil cement are one foot thick and eight to ten feet wide to allow for the use of standard construction equipment. Several lifts are placed on top of each other to achieve the desired height. After the soil cement lifts are laid down the excavated area would be backfilled with soil/sand excavated from the riverside of the levee face. The proposed active work area (i.e., area proposed for soil excavation adjacent to the levee, soil cement construction, construction access routes, and storage of equipment and materials) would extend about 6.2 miles along the levee and 120 feet from the toe of the levee. Activities within the construction area would include removal of vegetation (i.e., grasses, scrub), soil/sand excavation, stockpiling of soil/sand and materials, and construction of the soil cement barrier. Vegetation removal is not proposed outside of the construction area; however, the construction area would be disturbed by the use of temporary access roads within sandy areas, and the use and storage of equipment. Additional staging/stockpile areas would be located outside the river channel on County or city of Santa Maria owned property. Proposed locations (Figure 1-1) include: (1) east of Highway 101 near the Broadway exit, (2) east of Suey Road Crossing, and (3) at upstream end of the Project area within the City of Santa Maria Landfill. Three batch plant locations (Figure 1-1) would also be required: 1) Batch Plant No. 1 (30,100 sq ft.) would be located immediate west of Blosser Road; 2) Batch Plant No. 2 (27,300 sq ft.) would be located about 400 feet north of the Highway 101; and 3) Batch Plant No. 3: (105,800 sq ft.) would be located on the levee landward side within the City of Santa Maria Landfill boundary. Both batch plants no. 1 and 2 would be located within the 120 feet active work area. Additionally, existing groins and a training fence constructed for the original project along the south levee, which occur within the identified construction area, would be demolished. A total of 63 groins (Figure 2-6) would be removed (approximately 277 cubic yards) and demolished materials would be taken to county of Santa Barbara or city of Santa Maria owned property, adjacent to the south levee. The original groin and training fence areas would be regraded for soil cement and backfilled.

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Construction Equipment of Soil Cement Construction equipment would include one bulldozer, three scrapers, four dump trucks, one hydraulic excavator, one skip loader, one vibratory roller, and one water truck. All construction equipment would be able to access the soil cement operation from the maintenance road on top of the levee. Scrapers would be used for the demolition of the groins and loaders for transport. Construction Route of Soil Cement The proposed transportation route would utilize Blosser Road, Donovan Road, Main Street, the Broadway off ramp and existing service roads adjacent to the levee (see Figure 1-1). Existing levee and access roads would be used for the removal and disposal of the groins. Construction Duration Construction of the soil cement is expected to occur over an approximately three year period: Reach 2 – one year; Reach 1 – seven months; and Reach 3 – one year and six months (Construction of the Sheet Pile would be included within this time frame). Construction is scheduled to begin in September 2009. Weather, funding, and mechanical constraints could delay construction through year 2014. The portable batch plant would be located at each Reach and moved as each construction reach is completed. Proposed construction hours would be 7:00 A.M. to 6:00 P.M., Monday through Friday. In-channel construction would not take place during the rainy season, defined as January, February, and March. Likewise, construction will be halted and equipment removed from the channel for non-seasonal rain events that could lead to substantial flows through this region. A spill prevention and contingency plan, dewatering plan, and stormwater pollution prevention plan would be prepared by the Corps to reduce impacts to water resources/hydrology. Please see Environmental Commitments BR-6 through BR-8, and ER-1 and ER-2 in Section 7 for measures that will be incorporated to reduce impacts to water resources/hydrology and biological resources. Construction activates would be monitored by environmental staff to ensure that impacts to environmental resources are minimized. A mitigation monitoring plan has been developed and is included as an Appendix to this EA. 2.3.3

Sheet Pile Alternative

As described above, sheet pile walls consist of a series of panels with interlocking connections driven into the ground with impact or vibratory hammers to form an impermeable barrier. This method could be used without disturbing the existing levee and if the levee were to erode because of impinging flows, the steel sheet pile would form a wall that would prevent the breach of the levee. The sheet pile is designed based on the worst case condition and this design scour would expose the sheet pile for a vertical height of up to 30 feet. The sheet pile would be driven approximately 69 feet deep to ensure anchorage should the scour be that extreme (see Figure 2-4 above for typical cross-section). Tiebacks would be required at 10 feet intervals located near the top of the sheet piles and due to the relatively

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narrow levee cross section, a screw type tieback anchor would be used. The construction of the sheet pile would require very little impact on existing vegetation. The top of the river side of the levee would require minimal excavation to provide access to install the tiebacks and concrete pile cap. No excavation would be required in the riverbed for this alternative. Training fences would be removed, but no groins would be removed. The construction process, equipment, and route for the Sheet Pile Alternative would be the same as described for the sheet pile element of the Proposed Action (see Section 2.3.2 for a detailed discussion), except that the sheet pile alternative would include the use of sheet pile throughout the length of the Project area. As described above, the Project is broken into three reaches (see Figures 2-3 to 2-5). Access to the west end of Reach 1 is via a gated entry from Blosser Road, immediately east of the Highway 101 Bridge. Access to the middle of Reach 2 is via a gated entry ramp from the city street to the top of the levee. Access to the levee between Reach 2 and 3 is via two gated entries at the Suey Crossing Bridge. Access to further upstream portion of Reach 3 is via a gated entry at the east end of the active landfill adjacent to the levee. 2.3.4

Soil Cement Alternative

As described above in Section 2.3.2, soil cement is a densely compacted mixture of cementitious material, soil aggregate, and water. The mixture is compacted to form a hardened structure with specific engineering properties. Soil cement is useful as a liner because the material has higher compressive strength and lower hydraulic conductivity than the non-cemented soil. The soil cement slope protection is economically attractive in Santa Maria because suitable rock is not available within economical haul distances. This alternative consists, essentially, of overlaying the original riprap revetment with a new continuous revetment of soil cement. Through excavation of the river bed immediately adjacent to the levee, the levee slope of two feet horizontal to one foot vertical (2H:1V) would extend down to the required scour depth (see Figure 2-5 above for typical cross-section). As described above, the existing riprap revetment would not be stripped off of the levee before the soil cement would be placed. Instead, soil cement would be placed against the existing riprap. The excavated material would be the source used to generate the soil cement for the new revetment. Once mixed in an on-site plant, the soil cement would be compacted in 1 foot thick and 8 feet wide layers. This operation would be repeated until the soil cement reaches the top of the levee. Once the soil cement is placed, the excavation would be backfilled with the material not used for the mixing of the soil cement. Because the volume of soil cement below the surface of the ground would reduce the volume of backfill needed, the backfill would only be a few inches shallower than the original riverbed elevation. After the necessary regrading, this would be undetectable. Training fences and groins would be removed, similar to the Proposed Action. Similar to the Proposed Action, pilot channels may be required to direct flow away from the construction areas. The SBCFCWCD has excavated pilot channels within the Santa Maria River many

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times in the past in an effort to train river flows away from the levee as part of their annual routine maintenance. While existing pilot channels would be used the modification of existing pilot channels and/or creation of additional pilot channels may be required. If pilot channel excavation is required, the excavated material may be used as additional borrow material for soil cement construction. Dimensions of the excavated pilot channels would be as described above in Section 2.3.2. Project access points would be identical to the Sheet Pile Alternative. Please see Section 2.3.2 for a detailed discussion of the soil cement construction process, equipment, route and duration. 2.4

OPERATION AND MAINTENANCE

The SBCFCWCD would conduct all Operation and Maintenance (O&M) activities associated with the Proposed Action that are contained in the Operation and Maintenance Manual for Santa Maria Valley Levees and Channel Improvements. Any required permits would be obtained by the SBCFCWCD from the Resource Agencies and the Regulatory Branch of the Los Angeles Corps Office prior to commencement of the O&M activity. Operation of the levee includes the following: Mobilization – Responsibility for providing sufficient equipment, material, and trained personnel for adequate operation of the project units in times of flood emergency. Coordination – Appropriate measures are to be taken to insure that the activities of all local organizations connected with the protective works are coordinated with the operating agency during flood periods. Inspection – Scheduled patrolling of flood control activities during periods of storm runoff in order to detect and correct any condition which endangers the structure. Also included is a complete inspection following each major high water period, to ascertain if any other damage has occurred. Multi-Purpose – All uses of flood control facilities which do not involve conveyance of storm runoff. They include, but are not limited to, water conservation, wetland/wildlife habitat, water quality functions, and development for increased land utilization. Maintenance of the levee includes the following: Inspection – Inspections shall be made as are necessary to insure that the flood control facilities are maintained in a properly functioning condition. Training – Responsibility for implementing a program, subject to Corps review, to provide an adequate number of trained personnel to perform the various functions of operation and maintenance under either normal or flood-emergency conditions. Public Interest – Responsibility for providing police protection of the project units and the responsibility for public health and safety in connection with the various flood control facilities.

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

Repair – After a major high water period, portions of the levee system may require re-grading of areas where buried soil cement is exposed and would require compaction and reconstruction of the levee where sheet pile is exposed. These potential repair measures are discussed in greater detail below and in the DDR. A discussion of O&M activities and potential impacts from these activities is included in the impact discussion of each environmental resource in Section 4. The Corps will prepare an O&M manual upon completion of the Project construction. The O&M manual will be reviewed by the Environmental Resources Branch (ERB), which will ensure that all environmental commitments are incorporated in the O&M manual. The SBCFCWCD must obtain all necessary permits to implement maintenance of the Project. If environmental conditions change or any new federally or state listed species appears in the Project area, the SBCFCWCD should consult with the U.S. Fish and Wildlife Service (USFWS), National Marine Fisheries Service (NMFS), or California Department of Fish and Game (CDFG), as appropriate. 2.5

MEASURES INCORPORATED IN THE PROPOSED ACTION TO REDUCE ENVIRONMENTAL IMPACTS

Several measures and commitments have been incorporated into the proposed Project that would reduce or avoid known potential impacts to environmental resources. These measures are identified in Section 7. 2.6

COMPARISON OF ALTERNATIVES

Prior to the development of the combination Sheet Pile and Soil Cement Alternative, repair of the entire levee with soil cement was preferred from a technical standpoint over repairing the levee with sheet pile only. During evaluation of the alternative repair methods, the Corps developed cost estimates for the two alternatives, which revealed that stabilizing the entire levee with sheet pile would be far more expensive than implementing the soil cement alternative. In addition, the Sheet Pile would also introduce a public safety hazard (sheet pile would become a vertical wall after a scour event) not introduced by the Soil Cement Alternative. Because part of the Project’s purpose is to reduce public safety hazards associated with flooding, the Sheet Pile Alternative is not preferred compared to the Soil Cement Alternative for safety reasons. In addition, repair of exposed areas of sheet pile after a major high water event would require intensive and expensive compaction and reconstruction activities by the non-federal sponsor, requiring additional expense and additional disturbance to jurisdictional areas during the recompaction of the levee. Therefore, the Corps has determined that the Sheet Pile Alternative of the entire levee is feasible but impracticable as explained in the discussion below and in Appendix C, 404(b)(1) analysis. However, to avoid some of the environmental impacts that would occur under the soil cement alternative, the Corps developed the combination Soil Cement and Sheet Pile Alternative.

Final EA/MND

2-20

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

Based on the cost estimates presented in the Design Deficiency Report, construction of the Sheet Pile Alternative is almost three times more costly than the Soil Cement alternative, without taking into account the repeated maintenance activities required to repair the levee structure after moderate to large storm events. Initial construction costs to repair the entire levee with Sheet pile would be $116,994,863.80; Soil Cement would cost $ 41,076,615.00; and the combined Soil Cement and Sheet pile Alternative would cost $ 44,942,109.40. Likewise, maintenance costs would be substantially greater for sheet pile than for soil cement, due to the amount of effort and time involved in compaction activities, as well as the larger work footprint. Maintenance costs for the Sheet Pile Alternative are estimated to be approximately seven times higher than for the Soil Cement Alternative. Although initial direct impacts to biological resources would be higher where soil cement is used compared to sheet pile, impacts from maintenance would also be greater for the Sheet Pile Alternative in comparison to the Soil Cement Alternative. The levee has almost breached eight times during the last 45 years and has actually breached on one occasion. The impinging flow failure mode that caused those damages will still be operating within Santa Maria River after this project has been completed. If the sheet pile were to be used on the levee and the impinging flows eroded the channel invert, the resulting erosion would destroy the existing levee and riprap up to the sheet pile wall. This sheet pile wall, in the eroded condition, could extend as much as 30 feet high and a few hundred feet long. This would produce an extreme fall hazard for the public and a wildlife passage issue. To repair this erosion, a large portion of the levee would have to be reconstructed using a compacted fill operation with full compaction requirements. This maintenance work would have to be accomplished quickly because of the public safety concerns. Using history as a guide, there is a high probability of this erosion scenario playing out 9-10 times over the next 40 years. Under the Sheet Pile alternative, maintenance activities would be extensive and would result in similar temporary impacts to Waters of the U.S. over time compared to the Proposed Alternative. Under this alternative, intense maintenance would cause repeated disturbance and increase in turbidity to the Waters of the U.S. to fix the erosion. Incrementally impacts to Waters of U.S. would be significant in comparison to stabilizing levee with Soil Cement. The Sheet Pile Alternative would also introduce the potential for additional environmental impacts (noise, traffic) to occur over the lifetime of the Project. In comparison, if soil cement is used on the levee and the impinging flows erode the channel invert, the resulting erosion would only expose the soil cement at its 2H:1V slope. The levee itself would be completely untouched and intact. The only maintenance required would be simply to regrade the riverbed to fill the scoured area without any compaction requirements. If this maintenance operation were to be delayed, there would be no detrimental effects to the project’s functionality, no safety hazard, and no pressing need for the operation to occur. However, because of the immediate potential impacts to the California red-legged frog in the upper 1700 feet of the project area, the Sheet Pile and Soil Cement alternative was formulated. This alternative uses soil cement over the vast majority of the project area because it is the superior design approach, while using sheet pile for the 1700 feet where the immediate impacts outweigh the risk of

Final EA/MND

2-21

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

increased maintenance. This reduces disturbance of adjacent riparian habitat in this reach and minimizes impacts to sensitive biological resources. Each alternative would result in substantially similar impacts relative to air quality, water resources, earth resources, cultural resources, and most other environmental issue areas. The use of sheet pile minimizes impacts to adjacent habitat and sensitive biological resources in the river channel, including the federally threatened California red-legged frog and riparian vegetation communities, while the use of soil cement construction in less sensitive areas maximizes the practical advantages of soil cement and limits environmental impacts associated with recompaction of the levee after major flow events. The Sheet Pile and Soil Cement Alternative achieves this balance while also fully accomplishing the project purpose and addressing the need for the project. In comparison with the Sheet Pile Alternative, the Soil Cement and Sheet Pile Alternative would result in lesser potential for scouring and breaching of the levee. The Sheet Pile Alternative is feasible from the NEPA point of view, but to stabilize the entire levee with Sheet Pile is not practicable in light of costs, logistics, and technology. Therefore, the Soil Cement and Sheet Pile Alternative is the Proposed Action. The loss of native habitat associated with the Soil Cement and Sheet Pile Alternative would be fully mitigated through the creation of new native habitat within the levee. The construction of the project would result in about 84.34 acres of temporary impact within the levee (see Table 4.2-1) and 8.99 acres of permanent impact. The 8.99 acres of permanent impact are currently comprised of 7.46 acres of native plant communities and 1.53 acres of non-native vegetation. Out of these approximately 70.54 acres of jurisdictional Waters of U.S. would be temporarily disturbed and approximately 7.46 acres of jurisdictional Waters of U.S. would be permanently impacted. As part of the project, all areas temporarily disturbed by project construction would be restored with native habitat. About 11.9 acres of non-native habitat exist within the temporary disturbance area and these areas would be re-planted with the native vegetation. Restoration of the area of temporary disturbance would result in about 65.91 acres of riparian vegetation and 19.3 acres of upland vegetation. Approximately 12.14 acres of this habitat would be considered newly created habitat. This habitat previously consisted of 9.5 acres of non-native annual grassland, 2.4 acres of ruderal habitat, and 0.45 acres of removed groin/barren habitat. The creation of 12.14 acres of new native habitat fully compensates for the 7.46 acres of permanent native habitat loss associated with construction of the proposed project. Table 2-1 summarizes the environmental impacts of the Proposed Action and alternatives in comparative form. Detailed descriptions of impacts are presented by resource in Section 4.

Final EA/MND

2-22

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

Table 2-1 Comparison of Alternatives Resource

Proposed Action Air Quality Construction emissions estimates for VOC and NOx are below the 100 tons per year for General Conformity de minimus thresholds and 25 tons per year guideline of the Santa Barbara County Air Pollution Control District for determining the significance of construction impacts. The Proposed Action is not regionally significant as the total of direct and indirect emissions represent less than ten percent of the nonattainment or maintenance area’s emissions inventories for all sources.

Level of Impact Sheet Pile Alternative Same as the Proposed Action. The air quality impacts of the Sheet Pile alternative regarding the Federal General Conformity Rule, toxic air contaminants and odors, would be similar to or less than those of the Proposed Action.

The proposed Project’s estimated emissions have been determined to be below the General Conformity applicability thresholds; therefore, by statute the proposed Project is presumed to conform with the State Implementation Plan (SIP).

Soil Cement Alternative Same as the Proposed Action. Since the difference in project schedule and duration would be very minimal, it is expected that the difference in emission estimates would also be negligible.

No Action Alternative No additional impacts to air quality would occur as a result of the proposed Project. However, repair of the Santa Maria Levee would not be implemented and continued flooding or erosion of the levee and adjacent roadway could occur. Flood flows that produce devastating impacts to the surrounding community could trigger the widespread use of equipment emitting at potentially significant levels for emergency repairs.

The proposed Project would not create significant incremental operating emissions, nor create the potential for significant operating emission impacts. There are no established ambient air quality standards for toxic air contaminants, but the proposed Project would comply with programs that focus on engines emitting diesel particulate matter and the measures to reduce emissions from construction equipment would minimize impacts from air toxics. Odor impacts from the proposed Project’s construction and operation would be less than significant. Environmental commitments to minimize fugitive dust (PM10) and to reduce NOx and PM2.5 from construction equipment would ensure that construction emissions are less than significant.

Final EA/MND

2-23

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

Resource

Proposed Action Biological Direct and indirect impacts to a highly disturbed, depauperate plant Resources community, would occur as a result of the removal of vegetation during construction activities. Construction activities could also potentially affect nesting migratory bird species. Environmental commitments would be implemented to avoid/minimize effects on nesting birds.

Level of Impact Sheet Pile Alternative No excavation would be required in the riverbed for this alternative. As a result, this alternative would not result in the removal of riparian vegetation within the channel.

Implementation of this alternative would avoid direct effects of the Project on wildlife species that Impacts to wildlife movement and movement of any native resident occur within the riparian corridor or migratory fish species is considered less than significant. and terrace habitat within the Santa Maria River. Although the Approximately 84.34 acres of temporary impact would occur within sheet pile alternative would avoid the levee and 8.99 acres of permanent impact. Of this temporary direct impacts to waters of the impact, approximately 70.54 acres of jurisdictional waters of the U.S. U.S., but will still require intense would be temporarily disturbed and approximately 7.46 acres of maintenance to repair scour from jurisdictional waters of the U.S. would be permanently filled. To winter storms and would result in reduce effects of the Proposed Action on jurisdictional waters, the long term operational effects to Corps would implement environmental commitments which require biological resources and waters of the restoration of disturbed areas to native scrub and riparian the U.S. Erosion along the toe of habitats. This would include the restoration of disturbed areas at the the levee would act as a barrier to conclusion of construction. To restore lost functions and services, the wildlife movement and alter the Corps will restore the degraded vegetation communities present in habitat conditions on the project the disturbance area and convert disturbed habitats to native plant area. Recompaction of the levee communities. where sheet pile is exposed would be anticipated to occur 8-10 times over the next forty years. Each recompaction activity would result in additional disturbance to jurisdictional areas.

Final EA/MND

2-24

Soil Cement Alternative Impacts would be similar to the Proposed Action, but at a slightly greater magnitude. Specifically, this alternative would result in the removal of the only intact riparian vegetation within the Project site. Were soil cement to be used on the levee and the impinging flows eroded the channel invert, the resulting erosion would only expose the soil cement at its 2H:1V slope. The levee itself would be completely untouched and intact. The only maintenance required would be simply to regrade the riverbed to fill the scoured area without any compaction requirements. If this maintenance operation were to be delayed, there would be no detrimental effects and no pressing need for the operation to occur.

No Action Alternative Under the No Action Alternative, the proposed improvements to the Santa Maria River Levee Project would not be implemented. As the No Action Alternative would not correct the deficiency from the original design, the damage that has been sustained would worsen over time, and could eventually result in complete failure of the levee, and therefore, disastrous flood damage. This would be inconsistent with the city of Santa Maria Safety Element, the county of San Luis Obispo and the county of Santa Barbara Seismic Safety and Safety Element, which call for the maintenance of flood control facilities to ensure adequate capacity. Additionally, as the Santa Maria River Levee provides drainage for the 100-year floodplain area, without the continued drainage of these channels, the viability of existing land uses would be precluded and the use or occupation of these uses could be precluded. Repairs required to repair the flood damage would likely have increased risk of significant impacts to biological resources as both the scale and scope of the clean-up effort would affect a larger area.

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

Resource

Proposed Action

Biological Resources

Water Impacts to surface and groundwater could occur from fuel leaks, Resources spills or the disruption of soils. Based on the location of the Project and depth of construction activities, it is not expected that groundwater flow would be affected by the Project.

Level of Impact Sheet Pile Alternative Under the Sheet Pile alternative, maintenance activities would be extensive and would result in similar temporary impacts to Waters of the U.S. over time compared to the Proposed Alternative. Under this alternative, intense maintenance would cause repeated disturbance to the Waters of the U.S. to fix the erosion. The Sheet Pile Alternative would also introduce the potential for additional environmental impacts (noise, traffic) to occur over the lifetime of the Project. Same as the Proposed Action.

The Proposed Action would not significantly affect percolation rates or drainage patterns in the area, and would not substantially alter the existing drainage pattern of the site or area, and does not include any actions or Project features that would substantially increase the rate or amount of surface runoff. Environmental Commitments incorporated into the Proposed Action would reduce potential impacts to water quality, groundwater supplies, existing drainage pattern and surface run-off.

Final EA/MND

2-25

Soil Cement Alternative

Same as the Proposed Action.

No Action Alternative

Under the No Action Alternative, the proposed improvements to the Santa Maria River Levee Project would not be implemented and the Corps would not be able to certify the levee, which was originally constructed in 1963, as being geotechnically and hydraulically capable of containing a 100-year storm event, as requested by FEMA. The city of Santa Maria would not be adequately protected against flooding during a 100-year storm event and would be susceptible to disastrous flood damage, including risk of life.

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

Resource

Proposed Action Earth A Stormwater Pollution Prevention Plan (SWPPP) would be Resources implemented and would include erosion control measures and best management practices to avoid or minimize impacts to earth resources and geology. The Proposed Action would not result in a landslide, lateral spreading, subsidence, liquefaction, or collapse. To ensure that impacts would not occur as a result of the levee improvement activities being located in an area with geologic conditions that are susceptible to seismic settlement and liquefaction, compliance with environmental commitments would occur, and impacts would be less than significant. Implementation of the sheet pile portion would introduce the potential for erosion and down-gradient sedimentation to occur both during construction and after the completion of sheet pile installation. In order to reduce the significance of this potential impact, disturbed soils would be restored following construction, and stockpiled soil materials would be managed to avoid or minimize potential for erosion and down-gradient sedimentation. Implementation of the sheet pile wall would not include excavation of sand, soil, or topsoil. However, the driving of sheet pile into the existing Santa Maria River Levee would cause vibrations but localized liquefaction is not anticipated to occur. Liquefaction would not likely occur because the soil is too dense. Potential exists for effects from earthquake-induced liquefaction including lateral spreading, which is essentially sliding of the levee into the channel. Further geotechnical investigations would be performed and results incorporated into Project design to ensure that any effects do not result in a significant geologic hazard.

Level of Impact Sheet Pile Alternative Implementation of this alternative would introduce the potential for erosion and down-gradient sedimentation to occur both during construction and after the completion of sheet pile installation. In order to reduce the significance of this potential impact, disturbed soils would be restored following construction, and stockpiled soil materials would be managed to avoid or minimize potential for erosion and downgradient sedimentation. Implementation of the Sheet pile Wall Alternative would not include excavation of sand, soil, or topsoil. However, the driving of sheet pile into the existing Santa Maria River Levee would cause vibrations but localized liquefaction is not anticipated to occur. Liquefaction would not likely occur because the soil is too dense. Potential exists for effects from earthquakeinduced liquefaction including lateral spreading, which is essentially sliding of the levee into the channel. Further geotechnical investigations would be performed and results incorporated into Project design to ensure that any effects do not result in a significant geologic hazard.

Soil Cement Alternative A Stormwater Pollution Prevention Plan (SWPPP) would be implemented and would include erosion control measures and best management practices to avoid or minimize impacts to earth resources and geology.

No Action Alternative The proposed improvements to the Santa Maria River Levee Project would not be implemented and it is reasonably assumed that geotechnical damage to the existing Santa Maria River Levee would continue to occur. In addition, the The Proposed Action would not result existing levee is not capable of containing the flow of a 100-year in a landslide, lateral spreading, subsidence, liquefaction, or collapse. storm event and would be expected to suffer catastrophic damage during To ensure that impacts would not such an event. Damage of this occur as a result of the levee magnitude would require emergency improvement activities being located flood-fighting response to protect the in an area with geologic conditions city of Santa Maria and would that are susceptible to seismic eventually require repairs or a new settlement and liquefaction, environmental commitments would be flood control structure be installed. As such, under the No Action implemented, and impacts would be Alternative, geologic affects less than significant. associated with levee repair and/or construction would still be expected to occur in the future, and would be of a greater magnitude than under the Proposed Action or the Project Alternatives.

A SWPPP would be implemented for this alternative as well.

Final EA/MND

2-26

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

Resource Land use

Proposed Action The proposed project would be compatible with adjacent land uses from the perspective of both existing uses as well as future uses.

Aesthetics The proposed Project would not substantially alter the existing viewscape and would not damage any scenic resources within a State scenic highway. Impacts would be less than significant.

Level of Impact Sheet Pile Alternative Same as the Proposed Action.

Same as the Proposed Action, except that use of sheet pile over a larger stretch of the project area would result in greater potential for exposure of the sheet pile. Until the levee is reconstructed, exposed sheet pile would create an aesthetic impact.

Recreation The proposed Project would cause no increase in the use of existing Same as the Proposed Action. neighborhood and regional parks or other recreational facilities. It would not include the construction of or induce expansion of any recreational facilities and construction would not occur on or directly adjacent to any recreational facilities.(The city of Santa Maria Bikeway runs along the top of the levee and the construction would potentially disrupt access to portions of this bikeway) Construction activities may result in temporary congestion or travel delays on local streets which also provide access to the recreation facilities, however access to recreational facilities would not be restricted. Impact on the use of the bikepath located along the top of the levee would occur. Prior to construction, the Corps would prepare a Traffic Management Plan, which would clearly identify all affected roadways, bikepaths, and pedestrian paths within the area of effect. The Plan would identify measures to notify the public and divert Final EA/MND

2-27

Soil Cement Alternative Same as the Proposed Action.

Same as the Proposed Action.

Same as the Proposed Action.

No Action Alternative The No Action Alternative would not correct the deficiency from the original design, the levee would continue to be at risk of failure during moderate flood events, and therefore, could result in disastrous flood damage. This would be inconsistent with the city of Santa Maria Safety Element, the county of San Luis Obispo and the county of Santa Barbara Seismic Safety and Safety Element, which call for the maintenance of flood control facilities to ensure adequate capacity. The proposed levee repairs would not be conducted. Flooding and erosion to the levee would continue to pose a serious concern to the stability of the adjacent roadways and to the residential areas on the south side of the levee. Ongoing repair and flood fighting activities would likely occur and the area would be subject to periodic visual impacts from construction equipment. The proposed levee repairs would not be conducted. Flooding and erosion to the levee would continue to pose a serious concern to the stability of the adjacent roadways and to the residential areas on the south side of the levee. Ongoing repair and flood fighting activities would likely occur. As these roadways may provide access to recreational facilities, the No Action Alternative could lead to the disruption of access for road repairs. This could result in impacts to recreational facilities over time. August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

Resource

Noise

Proposed Action automobile, bike, and pedestrian traffic safely around the construction area. Proposed Project impacts, therefore, would be less than significant. The temporary nature of the impact in conjunction with existing city regulations on hours of operation would lessen the potential of a significant impact due to construction noise. As all construction activity would occur between 7 a.m. and 6 p.m., construction of the proposed Project would not violate the City of Santa Maria Noise Ordinance. A small portion of residential development is shielded to the Project site by a noise barrier wall providing shielding effects. In addition, the levee construction site along residential areas is separated by the levee itself and a two lane road on the north edge of the residential developments. With the incorporation of environmental commitments N-1 through N-3, construction noise impacts would be less than significant.

Level of Impact Sheet Pile Alternative

Same as the Proposed Action.

Vibration impacts from sheet pile driving would be of a temporary nature and are not expected to exceed vibration perception thresholds of nearby individuals. Impacts are considered less than significant.

SocioConstruction of the Project would not increase the region’s economics population significantly. Implementation of the proposed Project activities would neither place a demand on employment opportunities, housing, or public facilities, nor would it create new employment opportunities, housing, or public facilities in the region. Consequently, the proposed Project activities would not create socioeconomic impacts within the adjacent communities and no impacts would occur.

Final EA/MND

Same as the Proposed Action.

2-28

Soil Cement Alternative

No Action Alternative

The temporary nature of the impact in conjunction with existing city regulations on hours of operation would lessen the potential of a significant impact due to construction noise. As all construction activity would occur between 7 a.m. and 6 p.m., construction of the proposed Project would not violate the City of Santa Maria Noise Ordinance. A small portion of residential development is shielded to the Project site by a noise barrier wall providing shielding effects. In addition, the levee construction site along residential areas is separated by the levee itself and a two lane road on the north edge of the residential developments. With the incorporation of environmental commitments N-1 through N-3, construction noise impacts would be less than significant. Same as the Proposed Action.

No construction related noise impacts to nearby residential receptors would occur under the No Action Alternative. However, under the No Action Alternative, the levee deficiency from the original design would not be corrected, leaving the levee at continued risk of failure during moderate flood events. Flood damage can result in physical impacts to the roadways, resulting in required construction activities on these roadways. Ongoing repair and flood fighting activities would likely occur.

Under the No Action Alternative, proposed flood control measures would not be implemented and continued flooding or erosion of the adjacent levee could occur. These activities would require flood fighting and emergency repairs but are not likely to result in substantial impacts to Socioeconomics of the region.

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

Resource

Proposed Action Transport- Traffic impacts would be short-term, and limited to the construction ation schedule. The transport of construction equipment and vehicles on affected roadways within the city of Santa Maria may cause periodic, temporary delays. However, this effect would not result in significant delays affecting level of service and road capacity, significantly affect the capacity or circulation patterns along the affected route, or require long-term road or access improvements beyond what is currently provided by levee service roads. Implementation of the proposed Project would not require additional road maintenance or the creation of new roads. In addition, the proposed Project would not limit access to or from adjacent land uses, and would not restrict emergency vehicle access. Construction activities would potentially affect the existing bikepath located along the top of the levee. Prior to construction, the Corps would prepare and adhere to a Traffic Management Plan which would identify measures to notify the public and divert automobile, bike, and pedestrian traffic safely around the construction area. The proposed Project would result in less than significant impacts. Hazardous No known hazards are located within the proposed Project area. Materials Impacts from general construction activities, including the use of and Waste small quantities of hazardous materials, such as petroleum Handling hydrocarbons and their derivatives (e.g., gasoline, oils, lubricants, and and solvents), to operate the construction equipment would be less Disposal than significant. Accidental spills or leaks during construction may contaminate the river, and underlying groundwater basin. However, the Corps would prepare a Spill Prevention and Contingency Plan for work within and adjacent to the Santa Maria River, and impacts would be less than significant. Two Conoco Phillips oil pipelines traverse the Santa Maria River and levee north of the city of Santa Maria (12-inch diameter pipeline extends north from North Railroad Avenue, 8-inch pipeline extends northeast from Ebony Street). The proposed Project would not require construction activities to the depth of the pipelines and impacts would be less than significant.

Final EA/MND

Level of Impact Sheet Pile Alternative Same as the Proposed Action.

Potential hazards issues and impacts associated with this alternative are identical to the proposed Project. However, with respect to the two oil pipelines that traverse the proposed Project site, implementation of the sheet pile alternative would require alternative methods of construction within the pipeline areas to avoid disturbance or harm potentially resulting pipe breakage, leaks, or spills. Impacts would be less than significant.

2-29

Soil Cement Alternative Same as the Proposed Action.

No Action Alternative The proposed Project construction would not be conducted. The No Action Alternative would result in further degradation of the existing levee and continued risk to residential areas and local roadways during flood events. Flood damage can result in the potential loss of life and property in the adjacent residential areas and physical impacts to the roadways. Ongoing repair and flood fighting activities would likely occur. As these roadways are heavily utilized by commuters, the No Action Alternative could lead to the disruption of access for road repairs.

Same as the Proposed Action.

The proposed upgrades to the Santa Maria River Levee would not be conducted. While no new hazards would be introduced, safety issues such as flooding as a result of a failure to the levee would persist. Ongoing repair and flood fighting activities would likely occur.

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 2. Proposed Action and Alternatives

Resource Safety

Proposed Action Flooding as a result of another breach in the levee could potentially result in the significant loss of life of individuals residing within the city of Santa Maria. The construction of the proposed Project would ensure that impacts to Safety would be less than significant.

Level of Impact Sheet Pile Alternative Same as the Proposed Action. Except , during a scour event similar to those on record, maintenance operations would be required within the riverbed to ensure that the levee protection did not remain a vertical wall. The vertical wall condition after a scour event would become a public safety hazard and a barrier to animal passage.

Cultural The Project area is not known to contain any historic properties. Same as the Proposed Action. Resources However, previous archeological surveys have identified cultural resources near the APE. Monitoring of construction activities would be conducted by a qualified archeologist, in case unknown resources are discovered. As a result, the Project would not have an adverse affect on historic properties. Public The proposed Project is not expected to result in an increase in the Same as the Proposed Action. Services local population, leading to a long-term increase in demand or use of and local wastewater service. There would be no operational impacts to Utilities existing wastewater provider’s capacities. There would be no operational impacts to existing schools, fire, or police department service capabilities. Operation of the channel would not generate solid waste and would therefore not affect existing landfill capacities. Impacts to public services and utilities would not be significant.

Final EA/MND

2-30

Soil Cement Alternative Same as the Proposed Action.

Same as the Proposed Action.

Same as the Proposed Action.

No Action Alternative The proposed Project would not be constructed and the levee deficiency from the original design would not be corrected. As a result, the Santa Maria River levee would continue to be at an increased risk of failure during moderate flood events and could result in flood damage. Significant impacts to Public Safety may occur to the residents of the city of Santa Maria. Ongoing repair and flood fighting activities would likely occur. Under the No Action Alternative, the proposed Project would not be conducted. No adverse affect would occur. No construction related impacts or temporary increases in public services or utilities demand would occur. However, under the No Action Alternative, correction of the levee design would not occur which could result in breaching of the levee during flood events. This flood water increases the amount of water treated by local wastewater treatment plants. Furthermore, ponding floodwater on local roadways results in an increase to police calls and increases traffic delays, resulting in an impact to emergency access and response times. Ongoing repair and flood fighting activities would likely occur.

August 2009

3. AFFECTED ENVIRONMENT

3.1

AIR QUALITY

This section presents information on ambient air quality conditions in the vicinity of the Project site and identifies potential impacts to air quality as a result of the construction and operation of the proposed Project. Sections 3.1.1 and 3.1.2 describe the existing setting as it relates to applicable regulations and air quality, respectively. 3.1.1

General Setting

Meteorological Conditions The climate of Santa Maria, northern Santa Barbara County is characterized as mild Mediterranean climate with warm, dry summers and mild winters with seasonally heavy precipitation that occur primarily during the winter months. Summer typically has clear skies, warm temperatures, and low humidity. A monthly climate summary for the city of Santa Maria was selected to characterize the climate of the study area. As described in Table 3.1-1, average summer (June-September) high and low temperatures in the study area range from 75°F to 50°F, respectively. Average winter (DecemberMarch) high and low temperatures in the study area range from 65°F to 38°F. The average annual precipitation range is 14.01 inches with over 76 percent occurring between December and March. Little precipitation occurs during summer because a high-pressure cell blocks migrating storm systems over the eastern Pacific. Table 3.1-1 Santa Maria Monthly Average Temperatures and Precipitation Month January February March April May June July August September October November December

Temperature Maximum Minimum 64 39 65 41 65 43 68 43 69 47 71 50 74 53 74 54 75 53 74 48 69 42 65 38

Precipitation Inches 2.64 3.23 2.94 0.91 0.32 0.05 0.03 0.05 0.31 0.45 1.24 1.84

Source: The Weather Channel 2008.

The proposed Project would be located in the Santa Maria Valley which is exposed to the relatively cool marine air from the Pacific Ocean. Prevailing winds in this area is primarily west northwest throughout the year except in August and October. Dominant prevailing winds directions are northwest in August and west in October. Air Quality Standards and Attainment Status The United States Environmental Protection Agency (USEPA), California Air Resources Board (CARB), and the local air districts classify an area as attainment, unclassified, or nonattainment,

Final EA/MND

3-1

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

depending on whether or not the monitored ambient air quality data shows compliance, insufficient data available, or non-compliance with the ambient air quality standards, respectively. The National and California Ambient Air Quality Standards (NAAQS and CAAQS) relevant to the Project are provided in Table 3.1-2. Table 3.1-2 National and California Ambient Air Quality Standards Averaging Time 1-hour 8-hour 24-hour Annual mean 24-hour Annual mean 1-hour 8-hour 1-hour Annual mean 1-hour 24-hour Annual mean

Pollutant Ozone (O3) Respirable particulate matter (PM10) Fine particulate matter (PM2.5) Carbon monoxide (CO) Nitrogen dioxide (NO2) Sulfur dioxide (SO2)

California Standards 0.09 ppm 0.070 ppm 50 µg/m3 20 µg/m3 — 12 µg/m3 20 ppm 9.0 ppm 0.18 ppma 0.03 ppm 0.25 ppm 0.04 ppm —

National Standards — 0.075 ppmb 150 µg/m3 — 35 µg/m3 15 µg/m3 35 pm 9.0 ppm — 0.053 ppm — 0.14 ppm 0.03 ppm

Notes: ppm=parts per million; µg/m3= micrograms per cubic meter; “—“= no standard Source: CARB 2008a a CARB has approved a revised 1-hour standard for NO2 (0.18 ppm or 338 ug/m3) and a new annual standard for NO2 (0.030 ppm or 56 ug/m3). These standards were recently approved by the Office of Administrative Law and are set to become effective as of March 30, 2008. b U.S.EPA has approved a revised 8-hour ozone standard of 0.075ppm. The attainment status, attainment plans and other requirements of this revised standard will not be fully implemented for several years.

The proposed Project area would be located along an approximately 6.5-mile reach of the southern Santa Maria River Levee, extending from the east side of the Santa Maria City Landfill to the north end of Blosser Road, adjacent to the city of Santa Maria, Fifth Supervisorial District. The proposed Project area would be located within the South Central Coast Air Basin (SCCAB), within the jurisdiction of the Santa Barbara County Air Pollution Control District (SBCAPCD). Table 3.1-3 summarizes the federal and state attainment status of criteria pollutants for the Project area based on the NAAQS and CAAQS, respectively. Table 3.1-3 Attainment Status for the South-Central Coast Air Basin Pollutant Ozone – 1 Hour Ozone – 8 Hour PM10 PM2.5 CO NO2 SO2

State Attainment Non Attainment Nonattainment Unclassified Attainment Attainment Attainment

Federal — Attainment Attainment Unclassified/Attainment Attainment Attainment Attainment

Source: CARB 2008b, USEPA 2008

Final EA/MND

3-2

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

Existing Air Quality The nearest ambient air quality monitoring station to the proposed Project site is Santa Maria- 906 S Broadway for ozone, PM10, PM2.5, carbon monoxide, and nitrogen dioxide. The nearest monitoring stations which monitor sulfur dioxide is the Nipomo, Guadalupe Road site in San Luis Obispo County. The last three years of maximum ambient monitored concentrations from these monitoring stations are provided in Table 3.1-4. Table 3.1-4 Air Quality Monitoring Summary 2003-2005 Pollutant Ozone (O3) Respirable particulate matter (PM10) Fine particulate matter (PM2.5) Carbon monoxide (CO) Nitrogen dioxide (NO2) Sulfur dioxide (SO2)

Averaging Time 1-hour 8-hour 24-hour Annual Average 24-hour Annual Average

2005

2006

2007

0.063 ppm 0.061 ppm 43 µg/m3 22.1 µg/m3 29.8 µg/m3 --

0.064 ppm 0.063 ppm 50 µg/m3 * 22.5 µg/m3 13.7 µg/m3 7.5 µg/m3

0.065 ppm 0.055 ppm 80.5 µg/m3 24.7 µg/m3 12.7 µg/m3 * --

8-hour

0.94 ppm

0.72 ppm

0.89 ppm

1-hour Annual Average 24-hour Annual Average

0.048 ppm 0.010 ppm 0.007 ppm 0.001 ppm

0.037 ppm -0.026 ppm 0.002 ppm

0.048 ppm -0.013 ppm 0.001 ppm

Source: CARB 2008c. -- Data not available * Excludes 2006 and 2007 firestorm events

This table shows, by comparison with Table 3.1-2, that exceedance of the federal and/or state PM10 standard is occurring near the Project site. The available concentrations of ozone and PM2.5 are under the most stringent standard. This table also shows that carbon monoxide, nitrogen dioxide, and sulfur dioxide concentrations near the Project site are all well below both federal and state standards. 3.1.2

Sensitive Receptors

Some land uses are considered more sensitive to air pollution than others due to the types of population groups or activities involved. Sensitive population groups include children, the elderly, the acutely ill and the chronically ill, especially those with cardio-respiratory diseases. Residential areas are also considered to be sensitive to air pollution because residents (including children and the elderly) tend to be at home for extended periods of time, resulting in sustained exposure to any pollutants present. Recreational land uses are considered moderately sensitive to air pollution. Although exposure periods are generally short, exercise places a high demand on respiratory functions, which can be impaired by air pollution. In addition, noticeable air pollution can detract from the enjoyment of recreation. Industrial and commercial areas are considered the least sensitive to air pollution. Exposure periods are relatively short and intermittent, as the majority of the workers tend to stay indoors most of the time. In addition, the working population is generally the healthiest segment of the public.

Final EA/MND

3-3

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

A land use survey was conducted to identify sensitive receptors (e.g., local residences, schools, hospitals, churches, recreational facilities) in the general vicinity of the proposed Project. The Project site is bordered by urban development, which includes a bike path parallel to and along the top of the levee, residential areas, a concrete company, and the Santa Maria Landfill. Agricultural land and undeveloped property are located across the river to the north. Residential areas and the bike path are considered as potential sensitive land uses, however, the bike path would be closed during construction. Additional information about specific sensitive receptors that may be impacted by the proposed Project will be provided with the evaluation of air quality impacts. 3.1.3

Regulatory Framework

The proposed Project includes construction but does not include any permanent stationary emission sources, so there are very few direct air quality regulations that specifically regulate the Project’s air quality emission sources. The regulations that do apply, such as fugitive dust regulations and rules for portable equipment, tend to be general and allow multiple means of achieving compliance. Descriptions of the specific and general regulations that apply to the Project are provided below. Federal The USEPA establishes the NAAQS for “criteria pollutants” that are considered harmful to public health and the environment. The limits set by the NAAQS protect public health, including the health of "sensitive" populations such as asthmatics, children, and the elderly, and they protect public welfare, including protection against decreased visibility, damage to animals, crops, vegetation, and buildings. Pollutants regulated under these standards include ozone, NO2, CO, PM10, PM2.5, and SO2. Additional information regarding the NAAQS that are relevant to the Project is provided in Section 3.1.1. The SBCAPCD and the CARB are the responsible agencies for providing attainment plans and meeting attainment with these standards; and the USEPA reviews and approves these plans and regulations that are designed to ensure that the area attains and maintains attainment with the NAAQS. USEPA has a number of other regulations under the authority of the federal Clean Air Act (such as New Source Review (NSR), Prevention of Significant Deterioration (PSD), Title V permitting program, etc.); however, these regulations for new sources do not directly apply to this Project because the Project would have no permanent operating stationary emission sources. The USEPA does have on-road and off-road engine emission reduction programs that indirectly affect the Project’s emissions through the phasing in of cleaner on-road and off-road equipment engines. State CARB also sets the CAAQS for criteria pollutants. These standards include pollutants not covered under the NAAQS, and these are more stringent standards than provided under the NAAQS. Pollutants regulated under these standards include ozone, NO2, CO, PM10, PM2.5, SO2, lead, sulfates, hydrogen

Final EA/MND

3-4

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

sulfide, vinyl chloride, and visibility reducing particles. Additional information regarding the CAAQS that are relevant to the Project is provided in Section 3.1.1. CARB, like USEPA, also has on-road and off-road engine emission reduction programs that indirectly affect the Project’s emissions through the phasing in of cleaner on-road and off-road equipment engines. Additionally, CARB has a Portable Equipment Registration Program that allows owners or operators of portable engines and associated equipment to register their units under a statewide portable program to operate their equipment, which must meet specified program emission requirements, throughout California without having to obtain individual permits from local air districts. Local The proposed Project is within SBCAPCD jurisdiction. The SBCAPCD is responsible for planning, implementing, and enforcing federal and State ambient standards within this portion of the South Central Coast Air Basin. The regulations of this agency are primarily focused on stationary sources; therefore, most of the local agency regulations are not relevant to this Project. However, portable engines used during construction that are larger than 50 horsepower and that are not registered under the CARB Portable Equipment Registration Program would need to obtain permits from the SBCAPCD. The SBCAPCD has visible emissions and nuisance regulations with which the Project’s construction will need to comply. The specific regulations are as follows: •

SBCAPCD Rule 302 – Visible Emissions

•

SBCAPCD Rule 303 – Nuisance

These rules limit the visible dust emissions from the Project construction sites and prohibit emissions that can cause a public nuisance. 3.2 3.2.1

BIOLOGICAL RESOURCES General Setting

The Santa Maria Valley is located in the central coast region of northern Santa Barbara County, California. The climate is mild with average annual temperatures falling between 40 and 75 degrees Fahrenheit. This semi-arid environment receives an average of 14-17 inches of rainfall per year. The availability of rich alluvial soils in this region makes agriculture the key component in this area’s economy with primary crops including strawberries, wine grapes, celery, lettuce, peas, squash, cauliflower, spinach, broccoli, and beans. Cattle ranches and oil fields are also prominent economic factors in this area. The exploration of oil played a major role in the growth of the region. Other land uses within the valley include commercial, residential, recreational, and urban areas. The city of Santa Maria is the largest city in Santa Barbara County.

Final EA/MND

3-5

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

The Project area encompasses 6.5 miles of the existing levee and adjacent Santa Maria streambed from the flood gates at the north end of Blosser Road eastward to the Santa Maria landfill at Bradley Canyon. Construction activities to repair and strengthen the levee would extend 120 feet (80 feet for excavation and 40 feet for stockpile and soil cement processing) from the toe of the existing levee into the Santa Maria streambed. Much of the upland area adjacent to the Project area has been subject to rapid changes in land use. Land uses on the south side of the levee include the Santa Maria Landfill; a concrete batch plant; a recreational bike and walking path that runs along the top of the levee; and growing residential communities. Agricultural fields are present adjacent to and within some sections of the floodplain and occur on the north side of the river. Irrigation ditches and pools which can support wildlife are present along the borders of the fields. At several points both dirt and paved roads cross the Project area including the overpass bridge for highway 101/166 and the “Suey crossing” at Bull Canyon Road. The Santa Maria basin (Twitchell Dam) is one of three large-scale Federal water projects in the region designed to capture the seasonal floodwaters to recharge aquifers. Approximately seventy-five percent of the supply reclaimed by the Santa Maria Water Project in the Santa Maria Valley goes to irrigation and most of this water comes from the Santa Maria River. The Santa Maria River, which serves as the county line between Santa Barbara and San Luis Obispo Counties, is formed by the confluence of the Sisquoc and Cuyama Rivers which are located northeast of the Project area. From the confluence, the river flows northwest towards the city of Santa Maria, turns west across the north end of the city and discharges into the Pacific Ocean. The river is dry most of the year but supports continuous flows during portions of the rainy season. During intense winter storms the river supports very high flows which flood adjacent terrace and upland areas. During periods of contiguous flow to upstream areas the river acts as a known migration corridor for the endangered steelhead trout (Oncorhynchus mykiss) to their spawning grounds in the Sisquoc River (www.lpfw.org). The section of the river within the Project area is a broad meandering alluvial streambed with a mosaic of riparian vegetation and sandy terraces barren of vegetation. This reach is subject to high flows during episodic rainfall events. The levee forms a steep rock rip rap slope along the southern edge of the streambed. Surface water was not present within the streambed during the time of the AugustSeptember 2008 surveys (Aspen, and Terra-Verde Environmental) however, dry algal mats and cattails were found in the channel at the eastern end of the Project area, indicating recent surface flow. The substrate of the stream bed is sandy and contains several terraces and secondary channels. There are dense patches of vegetation throughout the channel and surrounding streambed which provide adequate cover and nesting sites for several bird species including great horned owl (Bubo virginianus), observed in August 2008, and other wildlife species. Numerous small mammal burrows were observed in the banks and near the base of the levee. Channel alignment construction activities were underway within the proposed Project area to the east of the Bull Canyon Road crossing in 2008. These activities are the Santa Barbara Flood Control District’s Routine Maintenance Measures being implemented to protect the city of Santa Maria from potential levee failures, especially after the Zaca fire in 2007. This fire burned a substantial portion of the Santa

Final EA/MND

3-6

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

Maria River watershed. The subsequent loss of vegetation increases the potential for elevated discharge rates, discharge volumes, and sediment and debris loads to enter the river during the upcoming winter rainy season. Bulldozers were creating a 300-foot-wide by 2,200-foot-long pilot channel within the Santa Maria River bed by pushing two partially vegetated islands to the north and south. The Santa Maria River in the Project area supports a variety of plant communities. These vegetation communities are in large dependent on the hydrologic cycle of the river. In areas subject to routine scour from winter storms the area supports more early seral stages of riparian or pioneering vegetation. Likewise, access to water, both surface and subsurface, plays an important role in the ability of a plant to persist in within the floodplain. For example, older high elevation stream terraces located within the streambed that have not experienced recent inundation contain more established vegetation including more drought tolerant species such as coyote bush (Baccharis pilularis), scalebroom (Lepidospartum squamatum), and buckwheat (Eriogonum parvifolium). These areas also support biotic crusts that have developed over many years. Where disturbance from scour is more common early successional native and non-native plants are common and include sandbar willows (Salix exigua), mule fat (Baccharis salicifolia), and the weedy annual white sweet clover (Melilotus alba). Areas with less disturbance that retain access to ground water currently support larger woody vegetation such as arroyo willow (S. laseolepis), California bay laurel (Umbellularia californica), and the exotic blue gum (Eucalyptus globulus). A complete description of the vegetation communities present in the Project area is described below in Section 3.2.2 (Vegetation Communities). This section provides a general overview of the Project area and adjacent setting. For the purposes of this Final EA/MND the Project area has been defined by three separate Reaches. •

Reach 1: Blosser Road to Highway 101 Bridge (STA 649+00 to STA 711+50) is approximately 1.2 miles long;

•

Reach 2: Highway 101 Bridge to Suey Crossing Bridge (STA 711+50 to STA 819+00) is approximately 2.0 miles long; and

•

Reach 3: Suey Crossing Bridge to Bradley Canyon (STA 819+00 to STA 984+00) is approximately 3.1 miles long.

Reach 1 Reach 1 commences approximately 500 feet west of Blosser Road and runs eastward approximately 1.2 miles to the highway 101 bridge crossing. This reach is isolated from the river channel by large agricultural fields which occur on the adjacent flood plain. Residential housing occurs adjacent to the Project area along the entire south side of the reach from Blosser Road to the highway 101 bridge. A bike path runs between the residential area and the levee. Habitat associated with the residential area and bike path consists of disturbed annual grasses and ruderal habitat with some landscaped areas. Ornamental plantings of oaks are present along the residential area south of the Project site. While most of the levee consists of rock riprap or compacted earth some areas support weedy annuals including brome grasses (Bromus sp.), summer mustard, dove weed (Eremocarpus setigerus), and tree

Final EA/MND

3-7

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

tobacco (Nicotiana glauca). In one location a coast live oak (Quercus agrifolia) is present on the face of the levee. Most of the vegetation that occurs within the confines of the channel within areas subject to Project disturbance consists of a mosaic of semi-disturbed riparian and upland plant communities. Non-native grassland, coastal sage scrub, and coyote bush scrub communities dominate the majority of Reach 1. At Blosser Road, large agricultural fields abut the Project area. In some areas small pockets of remnant riparian and mulefat scrub occur particularly near the Highway 101 bridge crossing. These communities continually intergrade between one another for most of this reach. For example, large areas of annual grassland transition into more disturbed coastal scrub communities. At some locations pure stands of coyote bush scrub intergrade into mulefat scrub and annual grassland. The vegetation identified on these terraces suggests that with the exception of major floods these areas remain dry for extended periods. Most of the upland habitat in this area is degraded, and dominated by annual grasses and weedy herbaceous plants. However, patches of good quality habitat are present in the Project area. Numerous trails and dirt roads cross the upland habitat and lead down to the riverbed. These trails and roads show recent evidence of OHV use from motorcycles, mountain bikes, and other recreational uses. Reach 2 Reach 2 includes a 2.0 miles stretch of habitat between the Highway 101 crossing and Suey crossing. In some areas the habitat may be considered degraded. This Reach includes a wide alluvial floodplain where the active channel abuts the existing levee in several locations. Evidence of historic scour is common and two higher elevation stream terraces dominated by coastal scrub and riparian scrub extend into the active channel. A vacant lot dominated by non-native annual grasses and residential housing occurs immediately south of the Project area from the Highway 101 bridge to Suey Road crossing. A bike path runs along the levee in this location and pedestrian trails cross the Project area. Agricultural fields and large areas of open space occur on the north side of the river. Habitat associated with this Reach within areas subject to Project disturbance consists of various scrub communities. On higher elevation terraces coastal scrub dominated by golden bush, scale broom, golden yarrow (Eriophyllum comfertiflorum), wild tarragon (Artemesia dracunculus), and phacilia (Phacelia douglasii) is present. Riparian scrub is also a common element in this area and consists of dense patches sandbar willow, mulefat, and coyote bush. Weedy non-native species are common in this area and occur across the Reach. White sweet clover, tocalote (Centaurea melitensis), tree tobacco, and fennel (Foeniculum vulgare) are locally dense in many areas. In several locations restoration efforts are occurring with clearly defined planting beds of irrigated willows. In some locations these areas are identified by flagging. Access to surface water increases as the Project moves upstream. At the Suey crossing, the active portion of the low flow channel can abut the toe of the levee. However, ongoing channel maintenance activities are occurring and a new low-flow thalweg is under construction near the center of the floodplain. The SBCFCD performs annual routine maintenance within the Santa Maria River and this

Final EA/MND

3-8

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

can include the re-establishment of a pilot channel at the Suey Crossing, however this channel commonly needs re-construction to maintain its existence because it fills with sediment if the river receives at least average flows. Reach 3 Reach 3 includes a 3.1 mile section of the river from the Suey crossing to Bradley Canyon. The active channel is very close to the toe of the levee through much of Reach 3. This is especially true at the western end of the reach where most of the vegetation is at the toe of the levee and the active channel is extremely sparse. Most of the area south of the levee consists of agricultural fields, the Santa Maria Landfill, and a concrete batch plant. Ruderal habitat is common in these areas. A bike path/levee access road runs along the levee in this location. Within this reach, ongoing construction activities are currently underway to construct a low flow pilot channel. As described for Reach 2, the SBCFCD performs annual routine maintenance within the Santa Maria River and this can include the re-establishment of a pilot channel at the Suey Crossing, however this channel commonly needs re-construction to maintain its existence because it fills with sediment if the river receives at least average flows. In many areas the active channel is denuded and flagged for construction. Habitat associated with this Reach within areas subject to Project disturbance includes open channel, various riparian scrub communities, annual grasslands, and disturbed ruderal habitat. Most of the active channel has either been scoured of vegetation from recent storms or subject to clearing from previous construction activities. These consist of large areas of open sandy channel supporting scattered willows, mulefat, and ragweed. Ambrosia (Ambrosia chamissonis), mugwort (Artemesia douglasiana), and horseweed (Conyza canadensis) are also present. In many areas weedy annuals including white sweet clover, rip gut brome (B. diandrus), summer mustard (Brassica sp.), fennel, pepper weed (Lepidium latifolium), and Russian thistle (Salosa tragus) are common. Near the toe of the levee a thin ribbon of riparian vegetation occurs for several thousand feet before transitioning to more disturbed habitat near a construction access ramp. This habitat supports a mosaic of riparian scrub, mulefat scrub, and willow riparian woodland dominated by mulefat, arroyo willow, and sandbar willow. There is a sparse ruderal channel beyond this thin strip of vegetation. Further east the habitat is more xeric with coyote bush scrub and non-native annual grasses. At the upstream terminus of this segment a well defined secondary channel with multiple terraces is present. This channel is the terminus of the Bradley Canyon Channel and has been known to support California red-legged frogs. This area supports the best riparian habitat within the Project site and recent surface water hydrology was noted in the defined secondary channel. Portions of the reach support willow riparian woodland at this location. Cottonwoods (Populus fremontii), and a few scattered gum (Eucalyptus sp.) trees occur in this area. Several other hydric riparian associated plants occur at this location including rabbits foot grass (Polypogon monspeliensis), curly doc (Rumex crispus), nut sedge (Cyperus eragrostis), cattail (Typha sp.), and algal mats (Cara sp.). However, the cattail and algal mats were desiccated at the time of the survey. An old alluvial terrace dominated by coyote bush, scale broom, willow, mulefat and patches of buckwheat is also present. Broad swathes of

Final EA/MND

3-9

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

California sage brush with patches of giant wild rye (Leymus sp.) and prickly pear cactus (Opuntia phaecantha) are also present. 3.2.2

Vegetation (Channels and Overbank)

Vegetation communities identified during the surveys include: • • • • •

Arroyo willow riparian scrub Central coast riparian scrub Mulefat scrub Coyote bush scrub Central coast scrub

• • • •

Non-native grasslands Disturbed/ruderal Active agriculture Active channel/river wash

These plant communities were identified using aerial photographs and field surveys by Terra-Verde Environmental and Aspen Environmental Group (2008). Community definitions are from Holland (1986), Muntz (1974), and Sawyer and Keeler-Wolfe (1995). The acreages of the vegetation community types within the Project area are summarized in Table 3.2-1 and include a 120 foot wide by 6.5 mile long section of channel that commences from the toe of the levee and runs between Blosser Road and Bradley Canyon. Table 3.2-1. Vegetation, Habitat and Other Non Habitat Elements Community Type Arroyo Willow Riparian Riparian Scrub Mulefat Scrub Active Channel Coyote Bush Scrub Central Coast Scrub Subtotal Non-native Grassland Ruderal Subtotal Total Habitat Barren Groin Levee Road Access Ramp Subtotal Total

Acreage Within Levee

Acreage Outside Levee

Native Plant Communities 0.98 31.55 14.19 20.34 3.41 14.89 85.36 Non-Native Plant Communities 9.5 2.74 12.24 97.6 Other Non-habitat Features 0.02 0.67 19.79 2.12 0.55 23.15 120.75

Total Acreage

0 0 0 0 0.14 0 0.14

0.98 31.55 14.19 20.34 3.55 14.98 85.59

1.24 4.02 5.26 5.4

10.74 6.76 17.5 103.09

9.85 0.0 0 0 0 9.85 15.25

9.86 0.44 18.9 0.05 0.03 29.28 136

Arroyo Willow Riparian In the Project area this community is characterized by dense, broad-leafed, winter-deciduous riparian thickets dominated by arroyo willow (Salix lasiolepis), and scattered cottonwoods with patches of sand bar willow (S. exigua) along the margins of the reach. This community is generally found in moist to saturated sandy or gravelly soil, especially on riparian bottomlands within low gradient stream reaches. Within the Project area stands of arroyo willow are patchy and occur at the upstream section of the

Final EA/MND

3-10

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

river. These stands were generally found along the small defined channel that extends from the agricultural drain in sandy/gravelly alluvial soils. Riparian Scrub This community is generally found along streams and rivers but may also occur in floodplain areas. Central coast riparian scrub communities vary from open to impenetrable and are dominated by any of several willow species. The vegetation on the bars and banks of river channels generally require seasonal flooding. This community typically consists of newly emerging willows including sand bar willow, arroyo willow, mulefat, and cottonwood. In addition, Mexican elderberry (Sambucus mexicanus) is also known to occur in this habitat type. Along the Santa Maria River bed riparian scrub communities are common and occur both as thick ribbons of vegetation near the toe of the levee slope and in broad communities on terraces. Mulefat Scrub Mulefat scrub is an open dense scrub community dominated by mulefat, coyote brush, and white clover. In the project area summer mustard, annual grasses, and western ragweed are common. Other species include willows, isolated golden bush, and scale broom. Along the Santa Maria River Project area, this community occurs in patches on the sandy terraces, and within ephemeral agriculture ditches that drain into the riverbed. Coyote Bush Scrub Coyote bush scrub is a woody scrub community dominated by coyote bush, and typically occurs as a pioneering community on loamy soils. Other elements to this community include California sagebrush (Artemesia californica), sticky monkeyflower (Mimulus sp.), poison oak (Toxicodendron diversilobum), and black sage (Salvia melifera). Coyote bush scrub communities are low (generally 3-6 feet tall) with an herbaceous understory. Both the density and the composition of the shrub cover vary from site to site as does the herbaceous understory. In the Project region, this community occurs to some extent in all three reaches. Central Coast Scrub Central coast scrub consists of low (1-2 m tall), usually dense scrubland plants with mostly soft-woody shrubs that are adapted to semi-arid environments. With the exception of annual grasses this community is generally lacking or has a sparse herbaceous layer below. Most growth occurs in late winter and spring with flowering concentrated in the spring and early summer. This community is fireadapted. Stands may be dominated by California sagebrush or by California buckwheat (Eriogonum fasciculatum) with black sage and/or white sage (S. apiana) often occurring as associated species. Other shrubs commonly occurring include coyote bush, monkey flower, and Mexican elderberry. In the Project area, this community is characterized by large stands of mock heather (Ericameria ericoides) or golden bush (Isocoma menziesii var. vernonioides). Central coast scrub may occur on a variety of slopes and aspects from nearly level hilltops to steep xeric slopes.

Final EA/MND

3-11

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

Non-Native Grassland Non-native grassland communities consist of predominantly low-growing herbaceous and invasive vegetation that forms either a continuous ground cover on open hillsides and terraces or understory patches below emergent shrubs and woodlands. Many native flowering annual herb and perennial bulb species (wildflowers), as well as naturalized annual forbs and invasive exotics, are important components of grassland communities. In the Project area, these communities are dominated by brome and oat grasses (Avena sp.). Slender hair grass (Deschampsia elongata), veldt grass (Ehrharta calycina), barley (Hordeum murinum), and golden top (Lamarckia aurea) are other common elements. Disturbed/Ruderal Habitat Disturbed plant communities, also known as ruderal communities, are dominated by herbaceous, introduced, pioneering plant species that readily colonize open disturbed soil and thrive as a result of human impacts. Ruderal communities may provide a certain degree of erosion control for recently disturbed or graded areas, but such communities are also a threat to the natural biodiversity of an area. Invasive species continually distribute highly competitive propagules into otherwise native vegetation; however, if ruderal grassland stands remain undisturbed for more than five years they can undergo succession towards more stable and less weedy plant communities, such as coastal or riparian scrub (Zedler et al., 1993). In the Project area, disturbed habitats support thick weedy mats of summer mustard, field mustard (Brassica rapa), wild radish (Raphanus raphanistrum), tocalote, and Russian thistle. Cheeseweed (Malva parviflora), Italian thistle (Carduus pycnocephalus) and white sweet clover are also locally dense in some locations. Active Channel/river wash The river channel itself consists primarily of sands, small gravel and river cobbles with minimal vegetation. This area may be subject to annual flooding and little established vegetation is present. Vegetation was generally absent to sparse and consisted of a mix of native and non-native species. White sweet clover, tocalote, tree tobacco, and fennel are locally dense in many areas. Active Agriculture Active agricultural fields are a main feature of the landscape in Santa Maria. There are several agricultural fields present within and adjacent to the Project area. The main crops grown in the area include strawberries, wine grapes, celery, lettuce, peas, squash, cauliflower, spinach, broccoli, and beans. Surrounding lands are also used for cattle ranching. A complete list of the plant species identified in the Project area is presented in Table 3.2-2. Table 3.2-2. Plant Species Observed within the Santa Maria Levee Project Area SPECIES Achillea millefolium Ambrosia chamissonis Ambrosia psilostachya Anagallis arvensis*

Final EA/MND

COMMON NAME common yarrow beach-bur western ragweed scarlet pimpernel

3-12

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

SPECIES Apiastrum angustifolium Artemisia californica Artemisia douglasiana Artemisia dracunculus Aster chilensis Avena barbata* Baccharis pilularis Baccharis salicifolia Brassica nigra* Brassica rapa* Bromus diandrus* Bromus hordeaceus* Bromus madritensis ssp. rubens* Camissonia cheiranthifolia Carduus pycnocephalus* Ceanothus cuneatus Centaurea melitensis* Chamomilla suaveolens* Conium maculatum* Conyza canadensis Croton californicus Cyperus eragrostis Deschampsia elongata Distichlis spicata Ehrharta calycina* Epilobium ciliatum ssp. Ciliatum Equisetum telmateia ssp. Braunii Eremocarpus setigerus Ericameria ericoides Eriodictyon crassifolia Eriogonum parvifolium Eriophyllum confertiflorum Erodium cicutarium* Eschscholzia californica Eucalyptus globulus* Foeniculum vulgare* Gnaphalium californicum Gnaphalium luteo-album* Heliotropium curassavicum Hemizonia increscens ssp. Increscens Heteromeles arbutifolia Heterotheca grandiflora Hirschfeldia incana* Hordeum murinum* Isocoma menziesii var. vernonioides Lamarckia aurea* Lepidospartum squamatum Lessingia filaginifolia Leymus triticoides Lotus corniculatus Lotus scoparius Lupinus chamissonis Malacothamnus sp. Malva parviflora* Marrubium vulgare* Medicago polymorpha

Final EA/MND

COMMON NAME wild parsley California sagebrush Mugwort Tarragon Aster slender wild oats coyote bush Mulefat black mustard field mustard ripgut brome soft-chess brome red brome beach evening-primrose Italian thistle Buckbrush Tocalote pineapple weed poison-hemlock Horseweed California croton Nutsedge slender hairgrass salt grass veldt grass willow-herb giant horsetail turkey mullein mock heather yerba santa coastal buckwheat golden yarrow red-stemmed filaree California poppy blue gum Fennel California everlasting common cudweed Heliotrope Tarweed Toyon telegraph weed perennial mustard foxtail barley coastal goldenbush goldentop grass California broomscale California-aster beardless wildrye birdfoot trefoil Deerweed silver lupine Bushmallow Cheeseweed Horehound California bur clover

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

SPECIES Melilotus albus* Melilotus indica* Mimulus aurantiacus Nicotiana glauca* Opuntia phaeacantha Phacelia douglasii Picris echioides* Plantago erecta Plantago major* Polygonum sp.* Polypogon monspeliensis* Populus balsamifera ssp. Trichocarpa Quercus agrifolia Raphanus raphanistrum* Rhamnus californica Rumex crispus* Rumex salicifolius Salix exigua Salix lasiolepis Salsola tragus* Salvia mellifera Sambucus mexicana Senecio blochmaniae Silybum marianum* Solanum douglasii Solanum xanti Sonchus asper* Sonchus oleraceus* Stephanomeria elata Umbellularia californica Urtica dioica ssp. holosericea* Vicia sativa ssp. nigra* Vulpia myuros Xanthium strumarium

COMMON NAME white sweet clover sour clover bush monkey flower tree tobacco prickly-pear Phacelia bristly ox-tongue annual plantain common plantain Knotweed rabbits foot grass black cottonwood coast live oak wild radish coffee berry curly dock willow-leaved dock sand bar willow arroyo willow Russian thistle black sage Mexican elderberry Blochman's groundsel milk thistle Douglas' nightshade purple nightshade prickly sow thistle common sow thistle wire lettuce California bay laurel stinging nettle common vetch rattail fescue Cocklebur

* Indicates non-native species.

Special Status Plant Species Only one rare plant was identified within the Project area, Blochman’s groundsel (Senecio blochmaniae) a CNPS List 4 species. This species was common throughout the Project area on upland terraces, and although considered a plant of limited distribution Sate wide, remains a common species within the Project area. Listed plant species were not identified in the project site during surveys conducted in August and September by Corps biologists. Jurisdictional Habitats In the Project area, the Santa Maria River supports areas identified as both wetland and non-wetland “waters of the U.S.”. These areas were delineated based on a Jurisdictional Delineation completed by the Corps for this Project (Appendix H). For the purposes of this document the limits of the ordinary high water mark (OHWM) as determined by changes in physical and biological features, such as bank

Final EA/MND

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August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

erosion, deposited vegetation or debris, and vegetative characteristics have been used to describe nonwetland waters of the US. Table 3.2-3 provides a description of the representative plant communities and total acreage of Jurisdictional waters present in the Project area. Table 3.2-3. Total Acreage of Jurisdictional Waters in the Santa Maria River Levee Project Area Corps, RWQCB/CDFG Jurisdictional Habitat (Joint Jurisdiction) Community Type/Non Total in acres Habitat Element Native Plant Communities Arroyo Willow Riparian Riparian Scrub Mulefat Scrub Active Channel Coyote Bush Scrub Central Coast Scrub

0.98 31.4 12.57 20.35 1.06 7.65 74.01

Subtotal Non-Native Plant Communities Non-native Grassland 3.48 Ruderal

2.51

Subtotal 5.99 Other Non-Habitat Features Barren 0.02 Groin Levee Road Access Ramp Subtotal

Total 3.2.3

0.66 0.0 0.90 0.56 2.14 82.14

Wildlife

Riparian communities support some of the most diverse assemblages of wildlife and provide access to water, shade, and protection from predation. These areas also provide foraging habitat and are used for nesting and breeding by a number of species. The diverse riparian and upland community types that occur in and adjacent to the Santa Maria River provide habitat for a variety of resident and migratory wildlife species including several special status species. Of particular importance are riparian areas that provide potential habitat for several special status species including habitat for the federally listed California red-legged frog (Rana draytonii), least Bell’s vireo (Vireo bellii pusillus), and southern steelhead trout. Because the river is constricted by agriculture and urbanization the creek bed and adjacent riparian and upland habitat function as a movement corridor for a number of wildlife species. Wildlife observed within the Project area included a variety of common birds, small mammals, and reptiles (see Table 3.2-4).

Final EA/MND

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August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

Table 3.2-4. Wildlife Species Observed Within or Adjacent to the Santa Maria River Levee Project Area Common name Birds American crow American goldfinch Anna’s hummingbird Barn swallow Black phoebe Black-chinned hummingbird Brewers blackbird Bush tit California quail California thrasher California towhee Common yellowthroat European starling Great horned owl Greater roadrunner Gull, dead unknown species Herring gull House finch House wren Lark sparrow Loggerhead shrike Mourning dove Northern mockingbird Nuttall's woodpecker Red-tailed hawk Ringed turtle-dove Rock dove Says phoebe Song sparrow Turkey vulture Western scrub-jay Wilson's warbler

Corvus brachyrhynchos Carduelis tristis Calypte anna Hirundo rustica Sayornis nigrican Archilochus alexandri Euphagus cyanocephalus Psaltriparus minimus Callipepla californica Toxostoma redivivum Pipilo crissalis Geothlypis trichas Strunus vulgaris Bubo virginianus Geococcyx californianus Larus sp. Larus argentatus Carpodacus mexicanus Troglodytes aedon Chondestes grammacus Lanius ludovicianus Zenaida macroura Mimus polyglottos Picoides nuttallii Buteo jamaicensis Streptopelia risoria Columba livia Sayornis saya Melospiza melodia Cathartes aura Aphelocoma californica Wilsonia pusilla

Fish Mosquito fish

Gambusia affinis

Reptiles and Amphibians California red-legged frog Gopher snake Western fence lizard Side blotched lizards

Rana draytonii Pituophis catenifer Sceloporus occidentalis Uta stansburiana

Mammals Black-tailed jackrabbit Brush rabbit CA ground squirrel Coyote Domestic dog House cat

Lepus californicus Sylvilagus bachmani Spermophilus beecheyi Canis latrans Canis familiaris Felis catus

Final EA/MND

Species

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

Common name Kangaroo rat Raccoon

Species Dipodomys sp. Procyon lotor

Birds Birds were the most common vertebrates observed in the Project area and were identified by sight and sound during surveys. Common species observed within these same habitats included Anna’s hummingbird (Calypte anna), house wren (Troglodytes aedon), northern mockingbird (Mimus ployglottos), and house finch (Carpodacus mexicanus). Several common species were also detected utilizing scrub, and grassland communities in the Project area, including bushtit (Psaltriparus minimus), California quail (Callipepla californica), and lark sparrow (Chondestes grammacus). Gulls (Larus spp.) were observed in areas associated with the existing landfill in Reach 3. Additionally, many species commonly associated with human activity were observed along developed areas. These included American crow (Corvus brachyrhynchos), house sparrow (Passer domesticus), and European starling (Sturnus vulgaris). Raptors and other birds of prey are plentiful in the region, and suitable nesting and foraging habitat for raptor species occurs throughout the Project area. Red-tailed hawk (Buteo jamaicensis), greater road runner (Geococcyx californianus), and horned owl were among several species detected in the Project area. In addition, one stick nest was located in riparian habitat near the terminus of Reach 3. The Initial Study prepared by the Santa Barbara County Flood Control District also noted that several migratory bird species have the potential to nest in habitats within the Project site. These include but are not limited to, the yellow breasted chat (Icteria virens), yellow warbler (Dendroica petechia brewster), long-eared owl (Asio otus), sharp shinned hawk (Accipiter striatus), Cooper’s hawk (Accipiter cooperii), white-tailed kite (Elanus leucurus), and warbling vireo (Vireo gilvus). Wilson’s warbler (Wilsonia pusilla) an uncommon bird, was noted in riparian habitat within the Project area. Mammals Large mammals were not observed during the survey; however, coyote (Canis latrans) tracks and spoor were located in the drainage. The California ground squirrel (Spermophilus beecheyii) is another common species observed in the Project area. Because of the close proximity to urban development, the area is likely used by domestic animals such as house cats (Felis catus) and dogs (Canis familiaris). Also, numerous burrows were observed in the dirt and rubble along the toe of the levee. Amphibians Amphibians often require a source of standing or flowing water to complete their life cycle. However, some terrestrial species can survive in drier areas by remaining in moist environments found beneath leaf litter and fallen logs, or by burrowing into the soil. Agricultural ditches and ponds adjacent the

Final EA/MND

3-17

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

project areas are known to support amphibians. Although no amphibians were observed during the surveys the area likely supports common species including Baja California [Pacific] tree frogs (Pseudacris [regilla] hypochondriaca) and western toads (Anaxyrus [Bufo] boreas). California redlegged frogs, a federally threatened species have been documented in the Project area. Surveys conducted by the SBCFCWCD in 2008 identified three sub-adult California red-legged frogs near the upstream terminus of the Project area. Reptiles Although a number of common reptile species may occur within the proposed Project area, only sideblotched lizards (Uta stansburiana), western fence lizards (Sceloporus occidentalis) and a gopher snake (Pituophis catenifer) were observed during surveys (Aspen August 2008 and Terra-Verde, AugustSeptember 2008). The diversity of reptile species is related to the diversity of plant communities found on the site. Typically plant communities that have an abundant amount of leaf litter, rocks, and rotting logs would have a higher diversity than those areas that have been highly modified or disturbed. Habitat conditions in the Project area are likely to support a variety of reptiles. Native Fish The river was dry at the time of the survey, however, several agricultural ditches flowing adjacent the levee held mosquitofish (Gambusia affinis). In addition, the Santa Maria River is a known migratory route for steelhead trout and these native fish pass through the area during high flows. Unarmored threespine sticklebacks (Gasteroseus aculeatus williamsonii) and arroyo chub (Gila orcutti), an introduced species, are also known from the area. The tidewater goby (Eucyclogobius newberryi), another listed fish, occurs at the mouth of the river several miles downstream from the Project area. Special Status Wildlife Species Special-status species include those listed as threatened or endangered under the federal or California Endangered Species Acts, species proposed for listing, species of special concern, and other species which have been identified by the USFWS, CDFG, or local jurisdictions as unique or rare and which have the potential to occur within the study area. Each of these species was assessed for its potential to occur based on the following criteria: •

Present: Species was observed on site or in the same watershed (aquatic species only) during a site visit or recent focused survey, or population has been acknowledged by CDFG or USFWS.

•

High: Habitat (including soils) for the species occurs on site and a known occurrence occurs within 5 miles of the site within the past 20 years.

•

Moderate: Habitat (including soils) for the species occurs on site and a known occurrence occurs within the database search, but not within 5 miles of the site or within the past 20 years; or a known occurrence occurs within 5 miles of the site and within the past 20 years and marginal or limited amounts of habitat occurs on site; or the species’ range includes the geographic area and suitable habitat exists.

•

Low: Limited habitat for the species occurs on site and no known occurrences were found within the database search and the species’ range includes the geographic area.

Final EA/MND

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

•

Unlikely: Habitat requirements strongly associated with the species (including vegetation and soils) do not occur within the survey area or the known range of the species does not include the survey area.

These species include: •

Tidewater goby (Eucyclogbius newberryi)

•

•

Unarmored threespine stickleback (Gasterosteus aculeatus williamsoni)

Two-striped garter snake (Thamnophis hammondii)

•

Burrowing owl (Athene cunicularia)

•

Steelhead trout (Oncorhynchus mykiss irideus)

•

Tricolored blackbird (Agelaius tricolor)

•

Arroyo chub (Gila orcutti)

•

Loggerhead shrike (Lanius ludovicianus)

•

Arroyo toad (Bufo californicus)

•

Least Bell’s vireo (Vireo belli pusillus)

•

California red-legged frog (Rana draytonii)

•

Yellow warbler (Dendroica petechia)

•

Western spadefoot toad (Spea hammondii)

•

American badger (Taxidia taxus)

•

Southwestern pond turtle (Clemmys marmorata)

•

Pallid bat (Antrozous pallidus)

•

California legless lizard (Anniella pulchra pulchra)

•

Townsend’s big-eared bat (Corynorhinus townsendii)

•

Coast (California) horned lizard (Phynosoma coronautm)

•

Western red bat (Lasiurus blossevillii)

Special Status Species Descriptions with the Potential to Occur in the Project Area Federal and State Listed Species Tidewater goby FE The tidewater goby (Eucyclogbius newberryi) is federally endangered and a California species of special concern. This species is native to California’s brackish water lagoons made by streams that flow into the sea. It prefers lightly saline cool water with sandy bottoms. It is mainly a coastal species although it has been found as far as 12 km upstream. It is known from the mouth of the Santa Maria River, however, it is unlikely to be found within the Project area due to lack of water in the summer months. Southern steelhead trout FE Populations of Southern steelhead trout (Oncorhynchus mykiss) from the Santa Maria River south to the southern extent of range (San Mateo Creek in San Diego) are federally listed as endangered. The National Marine Fisheries Service (NMFS) has designated critical habitat for the southern steelhead for this section of the Santa Maria River. Unit 3312 of the Santa Maria River Hydrological Unit provides for fish passage during periods of high flow to upstream breeding habitat. This species has physiological tolerances to warmer water and more variable conditions than its northern counterpart, and juveniles tend to grow faster and migrate to the ocean more quickly than northern populations. Numerous accounts of the Southern steelhead are known from Santa Barbara County (CNDDB 2007), and the Santa Maria River is a known migratory route. This species has the potential to occur within the Project area during high flows as a transient species during seasonal migrations.

Final EA/MND

3-19

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

California red-legged frog FT The California red-legged frog (Rana draytonii) is federally threatened and a CDFG Species of Concern. The California red-legged frog has been extirpated or nearly extirpated from 70 percent of its former range. Currently, California red-legged frogs are known from 3 disjunct regions in 26 California counties and 1 region in Baja California, Mexico (USFWS, 2006). This species is reported from the Santa Maria and eight of the nine surrounding quads. In 2008, SBCFCWCD biologists conducted protocol surveys for this species within areas supporting suitable habitat. Three sub-adult California red-legged frogs were identified near the upstream terminus of the project area. One frog was located 250 feet upstream from the upstream terminus of the project. Two other sub-adult frogs were located within the project area 275 feet downstream from the upstream terminus of the project. Subsequent surveys of these areas did not relocate the frogs and the shallow pools supporting these animals were dry. Surveys conducted within portions of the Bradley Canyon Channel also supported California red-legged frogs. During routine annual maintenance of the Bradley Canyon Channel SBCFCWCD biologists routinely locate between 20-50 frogs. During the summer when it is dry, there is a low possibility of encountering this species in the project area except during rain events or periods of high relative humidity. In the eastern extent of the Project area where agricultural field runoff feeds into the river channel there is a slightly higher chance of encounter. This is the area where the frogs were located. However, during the rainy season when seasonal pools form and the river has flow, this species has a high potential to occur in other portions of the Project area. The County of Santa Barbara has indicated that the primary crops in this area have shifted from lettuce and broccoli, water intensive crops, to strawberries which are drip irrigated. This crop conversion will further reduce the potential for California red-legged frogs to occur in the area outside the rainy season as access to perennial water may be more limited provided these crops remain the primary agricultural product in these fields. Least Bell’s vireo FE The least Bell’s vireo (Vireo bellii pusillus) is state and federally listed as endangered. The proposed Project is not located within designated critical habitat for this species (USFWS, 1994). This species is a summer resident and occurs within lowland riparian habitat along waterways and dry washes. The proposed Project area supports potential breeding habitat for this species in a variety of riparian habitat types (e.g., southern riparian forest and willow scrub). This species is reported from the Sisquoc quad. It is possible that during wet years this species could be found breeding within the Project area. If it were to occur in the Project area, the dense riparian channel at the eastern end of the Project would provide suitable habitat. Special Status Species Arroyo chub The arroyo chub (Gila orcutti) is a California Department of Fish and Game (CDFG) species of special concern. It is a small (generally 7-10 cm) cyprinid fish endemic to coastal streams of Southern

Final EA/MND

3-20

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

California. It feeds on algae, insects, and crustaceans. This species prefers warm, flowing (fast or slow) water with areas that are >40 cm deep and sandy or muddy substrates. The arroyo chub breeds from February through August. During the breeding season males develop bumps called breeding tubercles on their pectoral fins. This species is absent or rare in much of its native range, but abundant in portions of the Santa Margarita River, Malibu Creek, Trabuco Creek, and, San Juan Creek. Threats to this species include habitat modification due to urbanization, and competition with introduced minnow species such as the red shiner. No water was present within the Project area at the time of the surveys however this species was introduced to the Santa Maria River and could turn up during high flow events. Western spadefoot toad The Western spadefoot toad (Spea hammondii) is a CDFG species of special concern. This species is reported from the Santa Maria and five of the nine surrounding quads. The western spadefoot occurs in coastal sage scrub, chaparral, and grasslands, where it may be found in sandy washes, on floodplains and in low hills. Temporary breeding pools are a crucial requirement for the spadefoot’s continued occupation of an area. There is suitable habitat for this species in the eastern extent of the Project area where agricultural field runoff feeds into the river channel and along the grasslands and stream terraces where seasonal water may result in the formation of adequate breeding pools. Southwestern pond turtle The Southwestern pond turtle (Actinemys [Clemmys] marmorata) is a CDFG species of special concern. This species is reported from the Santa Maria and six of the nine surrounding quads. This species inhabits quiet waters of ponds, small lakes, streams, and marshes and requires basking sites such as partially submerged logs, rocks, mats of floating vegetation, or open mud banks. They will often inhabit reaches of streams that contain deep pools, with depths greater than three feet (Stebbins, 2003), and are typically found in the largest and deepest pools along streams containing suitable basking sites, including fallen trees and boulders. There is a low potential of this species being present within the Project area. There were ponds observed within a quarter mile of the Project area however deep pools are not present in the Project area. Silvery (California) legless lizard The California legless lizard (Anniella pulchra pulchra) is considered a CDFG species of special concern. In California, its range extends from Contra Costa County to the Mexican border. This species requires sandy or loose loamy soils under sparse vegetation for burrowing and is strongly associated with soils that contain high moisture content. It has been found in beaches, chaparral, or pine-oak woodland habitat and sycamore, cottonwood, or oak riparian habitat that grows on stream terraces. Potential habitat is present on the terraces in the various plant communities along the proposed levee. Therefore, this species has a moderate potential to occur.

Final EA/MND

3-21

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

Coast horned lizard The coast horned lizard (Phrynosoma coronatum) is a CDFG species of special concern. This species ranges from northern California to the tip of Baja California with the subspecies (P. c. blainvillii) in Southern California. It prefers areas with abundant open vegetation such as chaparral or coastal sage scrub. Coast horned lizards live exclusively on the ground and mainly rely on crypsis for predator defense. Their diet consists mostly of ants. This species is reported from four of the nine surrounding quads. Habitat and prey species are present for this species within the Project area. Two-striped garter snake The two-striped garter snake (Thamnophis hammondii) is a CDFG species of special concern. The species is reported from the Casmalia and Guadalupe quads. In general this species occurs mainly along Coast Range streams from Monterey Bay south to Baja California in elevation ranges ranging from sea level to approximately 2,500 meters. Its habitat includes perennial and intermittent streams with rocky substrate bordered by dense vegetation; the species is generally found near streams or stock ponds in the summer and occupies upland coastal sage scrub and grassy locations near its summer range in the winter. This snake is primarily aquatic and the lack of water in the Project area during the summer months make it unlikely that this species would be encountered. However, habitat in the eastern extent of the Project area is suitable for this species where agricultural field runoff feeds into the river channel. Burrowing Owl The burrowing owl (Athene cunicularia) is a CDFG species of special concern. This species has been reported within the Santa Maria quad. The burrowing owl is small and terrestrial. Burrowing owls favor flat, open grassland or gentle slopes and sparse shrubland ecosystems. These owls prefer annual and perennial grasslands, typically with sparse, or nonexistent, tree or shrub canopies. In California, burrowing owls are found in close association with California ground squirrels. Ground squirrels provide nesting and refuge burrows, and maintain areas of short vegetation height, which provide foraging habitat and allow for visual detection of avian predators by burrowing owls. In the absence of ground squirrel populations, habitats may become unsuitable for occupancy by owls. Suitable habitat for burrowing owls occurs throughout most of the Project area in the form of rodent burrows, ground squirrel colonies, sparsely vegetated channel banks, debris piles, and foraging habitat however, no sign of burrowing owls were observed (pellets, white wash, etc). Therefore, there is a low potential that this species would be found breeding within the Project area although it could potentially migrate through the area the rest of the year. Tricolored blackbird The tricolored blackbird (Agelaius tricolor) is a CDFG species of special concern (breeding). This species prefers annual grasslands, wet and dry vernal pools, and other seasonal wetlands. It is a California resident species. The tricolored blackbird is reported from the Sisquoc and Twitchell quads.

Final EA/MND

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August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

There is a moderate to low potential for this species to be found breeding within the Project area due to a shortage of suitable habitat. Loggerhead shrike The loggerhead shrike (Lanius ludovicianus) is a CDFG species of special concern (nesting). This bird preys on insects, amphibians, small reptiles, small mammals and birds and is known for killing its prey by impaling it on thorns or spines and severing the spinal cord with its beak. It generally lays 4-8 eggs in open-cup nests that are built in dense trees and shrubs. A loggerhead shrike was observed on a barbed wire fence running adjacent to the Project boundary. Suitable nesting and foraging habitat exists within the Project area. Yellow warbler The yellow warbler (Dendroica petechia) is a CDFG species of special concern (breeding). Yellow warblers are reported from the Sisquoc quad. These birds generally breed in late spring and migrate to wintering grounds in late summer. This species typically occurs in riparian areas with willows, cottonwoods, aspens, sycamores, and alders for nesting and foraging. It is also known to nest in montane shrubs in open conifer forests. They nest in trees, build cup nests, and tend to lay 3-6 eggs. This bird is one of the many host species for brood-parasitism of the brown-headed cowbird. There is a moderate likelihood that this species would be found breeding within the Project area as habitat is marginal and only found at the eastern end of the Project area, although this species may potentially use the area for foraging. American badger The American badger (Taxidea taxus) is a CDFG species of special concern. This species is reported from the Santa Maria and six of nine surrounding quads. Although habitat and prey species are present, no burrows that would be large enough to support badgers were observed. Therefore there is a low potential that this animal is within the Project area. Pallid bat The pallid bat (Antrozous pallida) is a CDFG species of special concern and forest service sensitive species. This species of bat occurs in a variety of habitats including deserts, grasslands, shrublands, woodlands, and forests. Pallid bats are most common in open, dry habitats with rocky areas for roosting. Suitable roosting habitat for bats within the Project site occurs under the two bridge overpasses and in trees along the riparian corridor. Bats may also forage in various other habitats within the study area.

Final EA/MND

3-23

August 2009

SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

Townsend’s big-eared bat Townsend’s big-eared bat (Corynorhinus townsendii) is a CDFG species of special concern. This species is reported from the Orcutt and Casmalia quads. It is not likely to be found within the Project area due to their habitat preference of large open roosts such as caves and cave-like structures. Western red bat The Western red bat (Lasiurus blossevillii) is a CDFG species of special concern. This species prefers riparian areas at mid-elevations where they roost in trees. This is a migratory species spending winters in lower latitudes. This species is generally solitary except for times of breeding and migration but it also may be found foraging in family groups. It has a low potential to be found within the Project area due to its habitat preference. 3.3 3.3.1

WATER RESOURCES AND HYDROLOGY General Setting

The proposed levee repair activities would occur along the Santa Maria River Levee, located in the Santa Maria River. This river forms part of the boundary between Santa Barbara and San Luis Obispo Counties in the central coast region of California, and is described in further detail below, under Section 3.3.2 (Surface Water). 3.3.2

Surface Water

The proposed levee repairs would occur on the Santa Maria River Levee, within the Santa Maria River and the Santa Maria River Hydrologic Unit. This Hydrologic Unit, or watershed, includes all tributaries of the Cuyama River, Sisquoc River, and Santa Maria River. The Santa Maria River Watershed is approximately 1,880 square miles, or 1.2 million acres, making it one of the largest coastal drainage basins in California (CRWQCB-CCR, 2008). The Santa Maria River forms approximately 20 miles east of the California coast at the confluence of the Cuyama and Sisquoc Rivers, which originate in wilderness of the Los Padres National Forest and are in relatively natural state. From the confluence where it originates, the Santa Maria River flows west to the Pacific Ocean. The Santa Maria Valley in the lower Santa Maria River Watershed, including the Santa Maria River, is highly altered (urbanized and channelized) and is contained by levees and a series of flood control channels and basins. The Santa Maria River channel is broad, sandy, and generally braided, with extensive levee protection against stormwater flows. There are no lakes or reservoirs on the Santa Maria River. Runoff from the Cuyama River is controlled by Twitchell Dam, which is located approximately six miles upstream of the confluence with the Sisquoc River that forms the Santa Maria River. Twitchell Reservoir provides flood protection as well as groundwater recharge.

Final EA/MND

3-24

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

The climate in this area is generally mild, with average precipitation higher in winter months (November through March) and low throughout the rest of the year. In 2007, the highest level of precipitation occurred in February (3.23 inches), while the lowest level of precipitation occurred in July (0.03 inch), with an annual total of 14.01 inches (DWR, 2008). Flow in the Santa Maria River varies depending upon releases from Twitchell Reservoir and precipitation. The Santa Maria River and its tributaries in the Santa Maria Valley are “losing” systems, which means that surface water flow rapidly infiltrates into underlying permeable layers (DWR, 2008). The river is a major source of recharge to the Santa Maria Groundwater Basin, which is described in further detail below in Section 3.3.3 (Groundwater). Roughly 500 square miles upstream of the Santa Maria River Levee (Project location), including the entire Sisquoc River watershed of approximately 471 square miles, is uncontrolled (USACE, 2007). In addition, roughly 26% of the Sisquoc River watershed (24% of all of the uncontrolled area) burned during the Zaca wildfire in August of 2007 (USACE, 2007). As is typical in a recent burn area, stormwater flows should be expected to be more intense than usual, both in quantity and in velocity. A reasonable estimate of annual peak flows in the Project area can be assessed based on data gathered at the USGS stream gage No. 11140000, near Garey. This gage is located just upstream of the Project area and monitors flow from about 94% of the uncontrolled drainage area. During the 44-year life of the Santa Maria River Levee (and improvements), annual peak discharge on the Sisquoc River has exceeded 8,000 cfs (cubic feet per second) twelve times, or once every 3 – 7 years (USACE, 2007). In 75% of the times that peak discharge has exceeded 8,000 cfs, the Santa Maria River Levee was damaged and either nearly breached, or actually breached (USACE, 2007). Using FEMA-simplified methodology to approximate post-fire discharge in the area, the Corps determined that 5-year storm flow would be 13,900 cfs, while 100-year storm flow would be 78,300 cfs (USACE, 2007). The Santa Maria River Levee is approximately 13 miles downstream of Twitchell Reservoir, and is within the inundation zone for Twitchell Dam (USACE, 2008). As such, the Project area would be subject to inundation if Twitchell Dam were to fail or breach. In addition, the Project area is approximately 5 - 22 miles inland from the Pacific Ocean, and could potentially be affected by a tsunami (earthquake-induced ocean waves). However, because of the broad nature of the Santa Maria River Basin and elevation of the Project site (65 feet), it is considered unlikely that the Project site would be affected by a tsunami (USACE, 2008). Surface Water Quality. The Project is located in Central Coast Regional Water Quality Control Board (RWQCB), Region 3, which has jurisdiction over a 300-mile long by 40-mile wide section of the State's central coast. Its geographic area includes all of the following counties: Santa Cruz, San Benito, Monterey, San Luis Obispo, and Santa Barbara Counties as well as the southern one-third of Santa Clara County, and small portions of San Mateo, Kern, and Ventura Counties. In the Project area, the Central Coast RWQCB is primarily concerned with water quality effects of heavy agriculture, with some oil production and steady urbanization. The Santa Maria River is currently listed on the 2006 CWA Section 303(d) List of Water Quality Limited Segments Requiring Total Maximum Daily Loads

Final EA/MND

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

(TMDL) for the following pollutants: nitrate, fecal coliform, and pesticides (ammonia, chlorpyrifos, name, Dichloro-Diphenyl-Trichloroethane (DDT), dieldrin, endrin). These pollutants most likely originate from agricultural sources that commonly occur throughout the watershed. 3.3.3

Groundwater

The Project site is located within the Santa Maria River Valley Groundwater Basin (Santa Maria Groundwater Basin), which underlies a surface area of approximately 184,000 acres (288 square miles) in the coastal portion of northern Santa Barbara and southern San Luis Obispo Counties. This groundwater basin is bounded on the north by the San Luis and Santa Lucia Ranges, on the east by the San Rafael Mountains, on the south by the Solomon Hills and the San Antonio Creek Valley Groundwater Basin, on the southwest by the Casmalia Hills, and on the west by the Pacific Ocean. Groundwater flow is generally westward toward the Pacific Ocean, although a large groundwater depression beneath Nipomo Mesa, north of the proposed levee repair activities, has directed groundwater flow locally toward the depression (DWR, 2004). The Santa Maria Groundwater Basin supplies groundwater to cities, water companies, oil operations, and agricultural operations throughout the Santa Maria Valley (SBC, 2005). Groundwater historically served as the only water source for Santa Maria Valley, but State Water Project supply currently provides an additional source of water. The Santa Maria River system is a major source of recharge to this groundwater basin. Twitchell Dam is operated to optimize groundwater recharge for the Santa Maria Groundwater Basin, with other, more minor sources of recharge including deep percolation of urban and agricultural return water, treated wastewater return, and septic tank effluent (DWR, 2004). Depth to Groundwater. Groundwater levels beneath Santa Maria Valley generally declined during 1945 through 1977, recovered by about 1986, declined again until about 1992, then recovered to near historic high levels by 1998 (DWR, 2004). In the Project area, the depth to groundwater along the existing levee is varied, and has ranged from 10 to more than 50 feet over the past twenty years, depending on annual rainfall and releases from Twitchell Dam (SBC, 2008). The level of groundwater in the Santa Maria Groundwater Basin is strongly connected to the flow levels in the Sisquoc, Cuyama, and Santa Maria Rivers, as well as Orcutt Creek (DWR, 2004). These waterways, as described above in Section 3.3.2 (Surface Water), are “losing” systems, which means that surface water flow rapidly infiltrates to recharge the underlying groundwater. The infiltration of water from the Santa Maria River appears to occur relatively steeply to nearly vertical under moderate flow conditions (USACE, 2008). The Preliminary Geotechnical Report for the Santa Maria River Levee, which was prepared by Fugro in 2007, reports that depth to groundwater along the levee varies, and has ranged from 10 to 50 feet over the past twenty years, depending on annual rainfall (SBC, 2008). Borings that were drilled along the north levee of the Santa Maria River in March of 1995 encountered groundwater at a depth of approximately 38 feet. In December of 1994, groundwater was encountered at a depth of more than 50 feet. Later, in 1998, Caltrans reportedly encountered groundwater at a depth of approximately 10 feet

Final EA/MND

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in borings drilled for the retrofit of the Santa Maria River Bridge. During the drilling for the original bridge in 1956, Caltrans encountered groundwater at a depth of approximately 72 feet. (USACE, 2008) Most recently, in November of 2008, borings conducted by SoCal Drilling in three locations (determined by the USACE) were drilled to just over 80 feet in depth and encountered groundwater at depths between 76 and 78 feet below ground surface (DYA, 2009). Each of these three borings was conducted along the proposed south levee alignment, approximately 20 feet from the toe of the slope (DYA, 2009). In addition to these three borings, 16 other borings were drilled to typical depths of approximately 50 feet and did not encounter groundwater (USACE, 2009). These borings are considered indicative of current groundwater conditions at the proposed Project site. It is possible for flows in the Santa Maria River to result in “mounding” of the level of underlying groundwater, which causes groundwater levels to rise to near-surface elevation. As a result, groundwater levels near the flowing river are also closer to the surface. Deeper groundwater levels tend to occur during dry periods and are generally farther away from the river. Soil moisture, groundwater level, and groundwater quality are expected to fluctuate seasonally in connection with precipitation, storm water runoff, irrigation intensity (withdrawals and recharge), and releases from Twitchell Dam. (USACE, 2008) Groundwater Quality. Groundwater character in the Santa Maria Groundwater Basin is generally variable. Total Dissolved Solid (TDS) concentrations vary throughout the basin, but tend to increase from east to west and increase toward the center of the basin (beneath the cities of Santa Maria and Guadalupe in Santa Barbara County), as well as southward, away from the recharge area of the Santa Maria River. Water tested at 78 public supply wells indicated average TDS content ranging from 139 to 1,200 mg/L. Historically, the Santa Maria Valley Groundwater Basin has been subject to high nitrate concentrations, particularly near the cities of Santa Maria and Guadalupe, with nitrate concentrations recorded as high as 240 mg/L. Some wells, particularly in the northern part of the basin, showed nitrate concentrations in excess of the Maximum Contaminant Level (MCL) between the years 1990 and 2000. High TDS, sulfate, or chloride content impairs groundwater in some parts of the basin. (DWR, 2004) 3.4

EARTH RESOURCES (GEOLOGY)

The Flood Control District of the Santa Barbara County Public Works Department retained Fugro West, Inc. to prepare a Preliminary Geotechnical Report for the Santa Maria Levee Project. This report, which was produced in May of 2007, indicated that the Project site is located within an area of alluvial deposits and artificial fill materials which compose the levee and adjacent street network. The principal fault in the area is the Wilmar Avenue Fault (part of the San Luis Range fault system), which merges with the Santa Maria River Fault near the US-101 bridge overcross. No active faults traverse the Project area. The report notes that there is a high potential for strong ground motion due to seismic events; however, the risk for fault rupture is not significant. The river channel deposits are likely susceptible to seismic settlement and liquefaction. The landslide risk within the Project area is low

Final EA/MND

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

along the southern bank of the river. The soils on the Project site are designated as “riverwash” (within the riverbed), and sandy alluvial land (along and adjacent to the levee). The levee was constructed with fill material. Soil characteristics are variable; however, erosion has been observed along the face of the levee. The final design of the levee would be required to consider factors of safety for slope stability during a seismic event. Currently, scour and erosion from river flows are compromising the stability and capacity of the levee. (SBC, 2008) 3.4.1

Geology

The following discussion of geology in the Project area appears in the Draft Design Deficiency Report for the Santa Maria Levee Project, as prepared by the US Army Corps of Engineers, Los Angeles District, in December of 2008 (USACE, 2008). Faulting. As mentioned above the principal fault in the site vicinity is the inferred trace of the Wilmar Avenue fault system. The Wilmar Avenue fault merges with the Santa Maria River fault near the Santa Maria River Bridge at US-101. The fault locations are interpreted from inferred offsets in well logs and steps in the Franciscan bedrock from geophysical data. The faults, as well as several others, are grouped as part of the San Luis Range fault system, which is potentially active. The fault locations are poorly constrained and lack clear evidence of displacement of Holocene dune sands or Quaternary alluvium in the Project vicinity. Within the river, the inferred locations of the faults are concealed by relatively deep alluvium. Seismicity and Strong Ground Motion. The site is located in a seismically active region of central California, and is relatively close to mapped active and potentially active faults. Moderate to strong ground motion has affected the site in the historical past. It is the Corps opinion that there is high potential for strong ground motion to affect the site in the future. Surface Fault Rupture. No known active faults cross the site and the site is not located within an Alquist-Priolo zone. Several faults are considered to be potentially active and are mapped across the Santa Maria River. These faults are generally associated with the Huasna, Wilmar Avenue, and Oceano Fault Systems, and include splays locally mapped as the Santa Maria River fault, the Santa Maria Fault, and Bradley Canyon Fault within the Project limits. The faults are generally concealed by alluvium within the Project limits. The presence of the faults is not expected to pose a significant rupture hazard relative to the life of the levee. Landsliding and Slope Stability. A relatively high bluff (up to 100 feet) forms the majority of the north bank of the Santa Maria River. Within the Project limits, along portions of the river, the base of the bluff is unprotected. The face of bluff is relatively steep, eroded, and commonly experiences landslides. The levees are generally outside the limits of the bluffs, and therefore have a low potential for being impacted by landsliding along the bluffs. Current practice is to design slopes using a minimum factor of safety of at least 1.5 for static loading conditions, and 1.1 for pseudostatic (earthquake) loading conditions. While no known slope instability has impacted the existing levee, it is

Final EA/MND

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expected that levee improvements would be designed to higher factors of safety than used for the existing levee slopes. 3.4.2

Soils

The following discussion of soils in the Project area appears in the Draft Design Deficiency Report for the Santa Maria Levee Project, as prepared by the US Army Corps of Engineers, Los Angeles District, in December of 2008 (USACE, 2008). Settling. The floor of the Santa Maria Valley is an alluviated plain of the Cuyama and Sisquoc Rivers. These rivers flow into one another near Fulger Point forming the Santa Maria River. The surface geology of the site consists mainly of units of flood plain alluvium (Qa) and channel deposits (Qg) associated with the river. Various rocks and formational materials crop-out or are mapped along the bluff and hillsides along the north side of the river and valley floor. These units typically consist of relatively thin units of stabilized dune sand (Qds) or older alluvial or terrace deposits (Qoa or Qt) overlying formational materials of Orcutt Formation (Qo), Paso Robles Formation (QTp), Careaga Sand (Tc), Monterey Shale (Tm), Obispo Tuff (Tot), and Franciscan mélange (KJfm). Locally the units are displaced by landslide deposits (Qls) or by faulting. Artificial fill materials (af) compose the levee embankments and roadways (such as US-101 and surface streets) in the site vicinity. Subsurface Conditions. The existing levee is an earthen embankment founded on alluvium. The alluvium along the Santa Maria River is predominantly well-drained sandy material with varying amounts of silt and gravel. At depth, and outside the active channel of the river, the alluvium is interbedded or can transition to clay. The foundation support soils for the levee mainly consist of relatively deep sediments of alluvium. Alluvium (Qg): Alluvial stream channel deposits are generally sediments deposited along the active or recent stream channel of the Santa Maria River. These deposits are predominantly medium to coarse sand, where exposed in the riverbed, and locally contain varying amounts and interbedded layers of gravel. The deposits are generally very loose to medium densities. The stream channel deposits within the Santa Maria River appear to be approximately 20 to 40 feet thick near the Central Coast Water Authority (CCWA) pipeline and US-101 alignments, respectively. The alluvium is typically underlain by dense older alluvium comprised of sand and gravel. Alluvium (Qa): The alluvium generally consists of flood plain and over bank sediments deposited along the Santa Maria River. The alluvium encountered along the Santa Maria River typically consists of several feet of silty topsoil that overlie granular sediments similar in composition and thickness to the stream channel deposits (Qg) described above. Scour and Erosion. Scour is general erosion and incision of the riverbed in association with river flow. Bank erosion occurs when the river rises and floods the banks, or intermittently when the river meanders, locally reaching the levee or riverbank. The riverbed materials are generally sandy, and would likely scour at relatively low stream flow velocities (possibly as low as 1 to 2 feet per second).

Final EA/MND

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

In addition, various gravel mining operations along the river remove sediment from the riverbed. Stream bank erosion and scouring below the toe of the existing rock slope protection have impacted the levee during past storm events, and are likely to again in the future. 3.5

LAND USE

Construction of the proposed Project would occur in three segments, which are referred to as Reach 1, Reach 2 and Reach 3. Reach 1 of the proposed Project would traverse the borders of San Luis Obispo County, the city of Santa Maria and an unincorporated area of Santa Barbara County. The north end of Reach 2 would border San Luis Obispo County and the city of Santa Maria, while the remainder of Reach 2 and all of Reach 3 would be located within the city of Santa Maria. Existing land uses immediately surrounding the Project area include residential, industrial, agricultural, and recreational development, and the Santa Maria Landfill. Specifically, areas north of the entire length of the Project and adjacent to the southeast end of the Project are designated as agriculture/open space, which includes a bike path and pedestrian paths parallel to the levee. The land uses south of Reaches 1 and 2 are designated as residential and industrial. In addition, the Santa Maria Landfill is located at the southeast end of Reach 3. Table 4.5-1 contains a list of the applicable land use polices the Project would be subject to. 3.6 3.6.1

AESTHETICS General Setting

The proposed Project site is bordered by urban development within the city of Santa Maria to the southwest and the Santa Maria River to the northeast. Urban development includes a bike path parallel to and along the top of the levee, residential neighborhoods, a concrete company, Northside Airpark, and the Santa Maria Landfill. Agricultural fields are present, adjacent to and within some sections of the floodplain and occur on the north side of the river. Irrigation ditches and pools are present along the borders of the fields. The levee and proposed Project site crosses under the US-101 bridge overpass. Existing structures within the proposed Project area include the levee, rocks along the levee face, soil cement and rock groins, metal fencing, station markers, a pipe and wire revetment, and the US-101 bridge overpass. Views of the proposed Project would be available primarily from the bike path along the top of the levee. The overall visual character of a site is defined by the landforms, water, vegetative patterns and existing man-made modifications that give the site its distinguishing visual qualities. The visual quality of a site involves a more subjective judgment of its overall attractiveness. The landscape along the levee is flat with little topographical relief. When viewing the levee the major visual backdrop is the Santa Maria River and open fields on the north side of the river. Considering the presence of the existing residential development, commercial buildings, concrete batch plant,

Final EA/MND

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agricultural land, and the Santa Maria Landfill, the project area as a whole has a low scenic quality as viewed from public vantage points. The visual sensitivity of an area is based on the public’s expectation of the area and the number of people viewing the area, as well as the duration and dominance of views. The public visual expectation of the area is for a mixture of residential, commercial and industrial land use. Overall, the landscape along the majority of the Project is of low visual sensitivity. 3.7

RECREATION

The area surrounding the proposed Project site consists mostly of residential development and agriculture on the south and southwest side of the levee and agriculture and vacant land on the north and northeast side of the levee. No recreational facilities or opportunities are located within the boundaries of the proposed Project site. However, a bike path is located along the top of the levee on the south and southwest, between the levee and urban development within the city of Santa Maria. Recreational opportunities within the immediate vicinity of the proposed Project site (less than 1.0 mile) include seven community parks: Grogan Park, Preisker Park, North Preisker Park, Jim May Park, Rice Park, Sierra Vista Park, and Tunnell Park. Recreational opportunities within these parks include athletic fields, picnic facilities, and perimeter walkways. Recreational opportunities within two miles of the proposed Project site include eight additional community parks: Oakley Park, Atkinson Park, Veteran’s Memorial Park, Armstrong Park, Simas Park, Joe White Park, Perlman Park, and Alice Threfts Park. The park amenities mentioned above are included at these parks as well. An abandoned airfield formerly known as Northside Airpark is located adjacent to the south side of the levee by Blosser Road. 3.8 3.8.1

NOISE General Setting

Noise Environment in the Project Area One primary noise source in the Project area is traffic noise from the adjacent streets that serve the proposed project area. Figure 1-2 contains an illustration of the major roadways in and near the study area. Traffic noise levels vary based on traffic volumes, vehicle speed, and type of vehicle. Passenger vehicle traffic generally generates less noise than large vehicles and trucks. According to the city of Santa Maria Specific Plan EIR, the major source of noise is motor vehicle traffic on roadways, with roadway traffic noise for major streets and highways in the vicinity of the Plan Area varying between 70 decibels (dB) Community Noise Equivalent Level (CNEL) and 60dB CNEL. In addition to the local traffic noise, the ambient noise conditions in the Project area are influenced by construction activity involving the ongoing Santa Barbara Flood Control District’s Routine Maintenance Measures near the Suey Road crossing and traffic associated with the Santa Maria landfill at the eastern end of the Project area.

Final EA/MND

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SANTA MARIA RIVER LEVEE IMPROVEMENT PROJECT 3. Affected Environment

Sensitive Receptors in the Project Area Some land uses are considered more sensitive to elevated noise levels because of the purpose and intent of the use. Places where people are meant to sleep, or places where a quiet environment is necessary for the function of the land use, are normally considered sensitive. For instance, residential areas, schools, places of worship, and hospitals are more sensitive to noise than are commercial and industrial land uses. The proposed Project site is located along an approximately 6.5-mile reach of the southern Santa Maria River Levee, extending from the east side of the Santa Maria City Landfill to the north end of Blosser Road. Adjacent land uses include residential, commercial, agricultural, recreational, and the city of Santa Maria Landfill (Figure 1.1). The proposed Project site is bordered by urban development within the city of Santa Maria to the southwest and the Santa Maria River to the northeast. Urban development includes a bikepath parallel to and along the top of the levee, residential neighborhoods, a concrete company, Northside Airpark, and the Santa Maria Landfill. Agricultural land and undeveloped property are located north of the proposed Project site across the Santa Maria River. The levee and proposed Project site crosses under the US-101 bridge overpass. Existing structures within the proposed Project area include the levee, rocks along the levee face, soil cement and rock groins, metal fencing, station markers, a pipe and wire revetment, and the US-101 bridge overpass. The residential community is located a minimum of approximately 150 feet from the levee west of Panther road and follows the levee trending northwest to North Blosser road. The area east of Panther road is primarily open space, commercial and agricultural land use. The city of Santa Maria requires that heavy construction should be limited to the weekday hours (7 a.m. to 6 p.m.) with minimal activity on weekends. In addition, the City would require the construction contractors to comply with all local sound control and noise level standards, regulations, and ordinances that apply to any work performed pursuant to the contract. 3.8.2

Measurement Standards

Ambient environmental noise levels can be characterized by several different descriptors. Noise Equivalent Level (Leq) describes the average noise level over a specified period of time. Leq provides a useful measure of the impact of fluctuating noise levels on sensitive receptors over time. Other descriptors of noise incorporate a weighting system that accounts for human susceptibility to noise irritations at night. CNEL is a measure of cumulative noise exposure over a 24-hour period, with a 5 dB penalty added to evening hours (7:00 pm to 10:00 pm) and a 10 dB penalty added to nighttime hours (10:00 pm to 7:00 am). Day/Night Average Noise Level (Ldn) is essentially the same as CNEL, with the exception that the evening penalty is dropped. Further, A-weighted noise levels that are exceeded a selected percentage of time can be classified as Lx, where x is the percentage of time that the noise level is exceeded during a given interval. Sound levels associated with L10 typically describe transient or short-term events (these noise levels occur about 10 percent of the time), while L90 levels generally describe background noise conditions. Ldn and CNEL values rarely differ by more than 1 dB.

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As a matter of practice, Ldn and CNEL values are considered to be equivalent and are treated as such in this assessment. In general, human sound perception is such that a change in sound level of 3 dB is just noticeable, while a change of 5 dB is clearly noticeable. A change of 10 dB is perceived as doubling or halving of sound level. 3.8.3

Applicable Regulations

Federal Regulations The U.S. Environmental Protection Agency (EPA) has developed guidelines on recommended maximum noise levels to protect public health and welfare (EPA, 1974). The EPA does not enforce these regulations, but rather offers them as a planning tool for state and local agencies. Table 3.8-1 provides examples of protective noise levels recommended by EPA. Table 3.8-1 EPA Designated Noise Safety Levels Effect Hearing Loss

Level Leq(24)