Adobe Creek Reach 5 Channel Improvement Project

DRAFT V1

ADOBE CREEK REACH 5 CHANNEL IMPROVEMENT PROJECT

Project Number:

PROPOSED PROJECT PLAN

Approved by:Approved by:

Beau Goldie, Project OwnerKatherine Oven

Deputy Operating OfficerAssistant Operating Officer

Lower Peninsula/West Valley Watershed DivisionCapital Program Services Division

Effective Date: Date:

Prepared By:

Senior Project Manager: (Pending)

Project Manager: (Pending)

Capital Program Services Division

DRAFT V1

TABLE OF CONTENTS

Page

I.PROJECT BACKGROUND......

A.Why do this Project?......

B.History & Background......

II.PROJECT OBJECTIVES / PROJECT BENEFITS......

III.PROJECT CRITERIA / CONSTRAINTS / ASSUMPTIONS......

A.Criteria......

B.Constraints......

C.Assumptions......

IV.PROJECT SCOPE OF WORK......

V.PROJECT SCHEDULE......

VI.PROJECT COSTS......

A.Expenditures and Costs (in thousands) by Fiscal Year......

B.Funding Schedule by Fiscal Year......

C.Sources of Funding......

D.Operating Budget Impacts......

APPENDICES......

Appendix A—Chronology of Board Actions......

Appendix B—Change History......

Appendix C—Glossary of Terms

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Adobe Creek Reach 5 Channel Improvement Project

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This Proposed Project Plan is a document that describes a District Capital project. It is a contract between Capital Program Services Division (CPSD) and the client Division on how the project will proceed. It provides an understanding of the project origins, establishes project objectives, and defines a proposed scope of work, schedule and costs for the project.

1. PROJECT BACKGROUND

A. Why do this Project?

Adobe Creek has a long history of flooding, with flood damages occurring in 1952, 1955, 1983, 1986, 1995, and 1998. The creek has problems such as localized flooding, creek bank erosion, failing channel stabilization structures, sedimentation, barriers to fish passage, and insufficient maintenance access.

This project will repair the eroded channel, stabilize banks, remove accumulated sediment, improve the channel conveyance capacity, and provide environmental benefits to the creek ecosystem.

If this project is not constructed, a section of Adobe Creek that is in serious disrepair will continue to erode during winter storm events, and the District will not have met its commitment to the local community to improve the conditions and flood conveyance capacity of this reach of the creek.

B. History & Background

Adobe Creek drains the northeastern slopes of the Santa Cruz Mountains (approximately 10.8 square miles) and discharges into the Palo Alto Flood Basin. Approximately 75 percent of the watershed area is mountainous and 25 percent of the watershed is located in the urbanized valley floor. The creek flows for 14.7 miles through the cities of Los Altos, Mountain View, Palo Alto, and the Town of Los Altos Hills.

The Adobe Creek project was originally identified and included in the 1986 Benefit Assessment Program approved by voters of the Northwest Zone. Data collection began in 1998 and a planning study for the section of creek between El Camino Real and Moody Road began in 1990.

In 1999, the Santa Clara Valley Water District (District) completed a planning report entitled “Adobe Creek Watershed Planning Study, consisting of the Engineer’s Report and Final Environmental Impact Report,” which addresses proposed channel modifications for Adobe Creek. The report identifies the recommended capital improvements for Adobe Creek upstream of El Camino Real and summarizes the environmental impacts and mitigations required. The 16 project reaches that encompassed the planning study are shown in Attachment A. Not all of these reaches were slated for improvements.

On June 15, 1999, the District Board certified the Environmental Impact Report (EIR) and adopted a resolution “approving general construction plans in the Engineer’s Report and determining to proceed with work of providing flood control protection measures on Adobe Creek from El Camino Real to upstream of Moody Road.”

Adobe Creek channel improvements between El Camino and Foothill Expressway (Reaches 1-4) are currently under construction and are scheduled to be completed by fall 2004. Between Foothill Expressway and Highway 280 (Reaches 5-9), channel improvements have not yet been completed.

Adobe Creek Reach 5:

The design for Adobe Creek Reach 5 was completed in 2002 and provided for one-percent protection in the creek channel from Foothill Expressway upstream to the West Edith Avenue Bridge. The proposed design included installation of gabions on the City of Los Altos’ side of the creek to protect groves of mature redwoods, and a stepped floodplain bench on the banks on the Los Altos Hills side of the creek. Construction of this stretch of creek required a certain acreage of mitigation planting, which the District proposed to install partly along the creek and partly in Edith Park, located just upstream of the W. Edith Road Bridge.

In April 2003, the Los Altos Hills City Council voted to not grant the District two of the necessary easements to construct the project and install the mitigation planting for Adobe Reach 5. There was significant community opposition to the proposed creek modifications and the proposed use of Edith Park for the mitigation planting.

In spring 2003, the District agreed to support a local community effort to obtain a state grant to develop an improvement plan for Adobe Reach 5 that would be acceptable to the community. This effort was led by the Adobe Creek Watershed Group (ACWG), comprised of creekside property owners and other members of the community. The ACWG was unsuccessful in obtaining this grant; however, a proposal was floated to undertake a collaborative effort between the District, the ACWG, the City of Los Altos, and the Town of Los Altos Hills to re-evaluate the improvement needs of Adobe Creek in this reach and develop a plan that could potentially lead to a new project effort.

In September 2003, the District, in partnership with local municipalities and the ACWG, initiated a collaborative effort to revisit the goals and objectives of providing flood and erosion protection for Reach 5 of Adobe Creek. This collaborative effort included District staff, ACWG members, other citizens, and staff from the City of Los Altos, the Town of Los Altos Hills, and various regulatory agencies. By December 2003, a conceptual approach for meeting the Collaborative’s objectives for creek channel improvements in this reach was attained. This Proposed Project Plan is a culmination of this process.

Adobe Creek Reaches 6 through 9:

No work is planned in Reach 6, although some channel modification may be necessary just upstream of the W. Edith Road Bridge depending on the proposed project that will be developed for Reach 5. The final design for channel improvements in Reaches 7-9 has been completed. Construction of this work may be delayed until improvements are completed in Adobe Reach 5.

1. PROJECT OBJECTIVES / PROJECT BENEFITS

1.Correct the existing erosion (ACWG #1)[1] to protect residences and creekside structures (NFP 1.2)[2] and stabilize creek banks (NFP 1.2, 3.6).

2.Open Reach 5 to eliminate backwater effects in Reach 6 (ACWG #2) by providing a scaled-down project (i.e., less than 1% flood protection) to a level of flooding acceptable to the community and local jurisdictions.

2a. Establish detailed hydrology in the vicinity of Reach 5 to determine anticipated in-channel and overland flow volumes on W. Edith Road and Fremont Avenue during a one-percent flood event.

2b. Improve channel conveyance capacity downstream of W. Edith Road Bridge to convey, at a minimum, the in-channel flow volume during a one-percent flood at W. Edith Road Bridge.

2c. Evaluate the options of expanding channel capacity downstream of the W. Edith Road Bridge to accept additional overland flows from Fremont Avenue during a one-percent flood. (Board Policy E-2.2 There is reduced potential for flood damages)

2d. Provide clear and documented understanding and acknowledgement of the existing flooding conditions in the vicinity of Fremont Street and W. Edith Road to the affected property owners and the Town of Los Altos Hills.

2e. Improve sediment transport to maintain channel capacity at W. Edith Road Bridge and minimize long-term maintenance.

3. Protect and enhance the creek ecosystem. (Board Policy E-3.1 Watersheds, streams and natural resources therein are protected and when appropriate, enhanced or restored.)

3a. Restore the riparian environment (ACWG #3)

3b. Maintain the creek’s meander (NFP 3.3)

3c. Create stable side slopes (NFP 3.6)

3d. Preserve as many trees as possible, including non-natives (NFP 2.2)

3e. Blend replanting of large and small trees (NFP 2.2, 2.3)

3f. Provide fish passage

3g. Preserve stream percolation capability

4.Minimize impact of mitigation (ACWG #4) on the community.

4a. Self-mitigating to the greatest extent possible (NFP 2)

4b. Additional mitigation sites, if necessary will be acceptable to the community (NFP 8.8)

4c. Create minimal disturbance to Edith Park (ACWG #6)

5.Minimize maintenance costs (ACWG #5).

5a. Provide long-term access for creek maintenance (NFP 4.4)

5b. Minimize access road impacts (NFP 2.4, 4.4, 8.3, and 8.8)

5c. Develop a well defined ongoing maintenance plan/guidelines (NFP 1.3)

6.Create an aesthetically pleasing project of which the Collaborative can be proud. (ACWG #7)

7. Collaborate to reach a successful conclusion (ACWG #8, NFP 8.8, 7.1)

8.Provide for the safety of children and the community.

9.Respond to all the ACWG concerns/issues regarding channel improvements and tree removal as documented during the Adobe Collaborative process in fall 2003.

10. Complete the proposed project within the remaining budget of the original Adobe Reach 5 project.

1. PROJECT CRITERIA / CONSTRAINTS / ASSUMPTIONS

A. Criteria

• The project will comply with all applicable federal, state, and local regulations and ordinances.

• The design flow will be determined by a detailed hydrologic evaluation of in-channel and overland flows in this reach of the creek. This will include separating out the area of Los Altos Hills that drains to the creek via the Robleda Drain.

• The design channel capacity between W. Edith Road Bridge and the Robleda Drain will be determined and agreed upon with the ACWG, the municipalities, and the regulatory agencies during the alternatives evaluation conducted during the planning phase.

The following Tolerances for Change shall dictate when this Project Plan shall be revised to reflect the updated project condition:

• Schedule tolerance - 3 months past the planned schedule for planning or design phase

• Cost tolerance – 10 percent of total costs for each planning, design or construction phase

B. Constraints

• Minimize disturbance to Edith Park

• The design will save the majority of the existing redwood trees along the northeast bank (Los Altos side) of the creek

• The design will minimize the removal of existing trees along the Los Altos Hills side of the creek.

• Property owners (Los Altos Hills, Rogez, Astiz, Millar, Theis, Assarson, Robinwood Pool, Van Horne) will dedicate the easement necessary for the project.

C. Assumptions

• Existing environmental baseline data from the 1999 Adobe Creek Planning Study can be used for the CEQA process for this project.

• Existing final plans and specifications for the previous Adobe Reach 5 project will be used to streamline the design phase for this project.

• Channel improvements in Adobe Creek Reach 6 upstream of this project reach will be limited to modifying the channel invert and associated banks to provide a smooth transition to the anticipated improvements under W. Edith Road Bridge.

• The construction of improvements for Adobe Creek Reaches 7-9 (modifications to Burke Road Bridge and O’Keefe Road Bridge) will be synchronized with this project.

• The community will provide timely input that will result in an aesthetically pleasing project.

• The ACWG will represent the community.

• The Adobe Collaborative will continue to operate to reach a successful conclusion.

1. PROJECT SCOPE OF WORK

The project will be completed in four main phases: Planning, Design, Construction, and Close-out. Work in each phase will follow appropriate Capital Program Services Division’s (CPSD) Quality Management System Procedures.

Planning Phase: (All work will follow the current CPSD Planning Phase WBS Item Descriptions and Instructions (W73002).

• Perform a detailed hydrologic analysis to determine the in-channel and overland flow components during a one-percent flood event.

• Develop alternatives for channel improvement, and, in conjunction with the ACWG, the municipalities, and the regulatory agencies, select a preferred plan and prepare an Engineer’s Report.

• Prepare appropriate CEQA documents and Mitigation and Monitoring Plan.

• Obtain regulatory permits to complete the project.

Design Phase: (All work will follow appropriate CPSD Design Phase WBS Item Descriptions and Instructions (W73004.)

• Prepare 30%, 60%, 90% and Final Plans, Specifications and cost Estimate (PS&E) package

• Work with the community and municipalities to define and obtain necessary rights-of-way to construct the project.

• Assist the Construction Administration Unit (CAU) to advertise and award construction contract.

Construction Phase: (All work will follow appropriate CPSD Construction Phase WBS Item Descriptions and Instructions (W73006).

• Provide biological monitoring and engineering support to the CAU during the construction phase, which will include re-vegetation as per the project design package.

• Assist the CAU in preparing and reviewing as-built plans.

• Complete transfer of ongoing maintenance to the Lower Peninsula/West Valley Watershed Division.

Project Close-Out: Complete project close-out requirements identified in the CPSD Project Delivery Procedure (Q75101).

1. PROPOSED PROJECT SCHEDULE

NOTE: The proposed project schedule presented below assumes that the District’s Board of Directors will approve the project in spring 2004 and direct staff to begin work at the start of Fiscal Year 2004-2005.

1. PROJECT COSTS

A. Expenditures and Costs (in thousands) by Fiscal Year

B. Funding Schedule by Fiscal Year

C. Sources of Funding

1. District Funds

2. Partnering Agencies

3. Reimbursement Schedule by Fiscal Year by Partnering Agency

D. Operating Budget Impacts

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Adobe Creek Reach 5 Channel Improvement Project

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APPENDICES

Appendix A—Chronology of Board Actions

List in reverse chronology, beginning with most recent Board Action.

Appendix B—Change History

Provide a Brief explanation of changes to project that required revision of Project Plan.

Appendix C—Glossary of Terms

Actual Expenditure:Money spent to pay for labor and overhead and services and supplies. It includes expenditure made against encumbrances.

Costs:Amount of money needed by the project for paying labor and overhead and services and supplies. It includes the planned expenditures and the planned encumbrances, but does not include expenditures made against prior year open encumbrances.

Encumbrances: Commitments related to unperformed (executory) contracts for goods or services. Encumbrances represent the estimated amount of expenditures that will result if unperformed contracts in process are completed.

Open Encumbrances: Committed total contract amount for goods or services less actual expenditures made against the committed amount.

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Adobe Creek Reach 5 Channel Improvement Project

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[1] ACWG: Adobe Creek Watershed Group Objective Number

[2] NFP: Natural Flood Protection Program reference number, currently under development by the Santa Clara Valley Water District.