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HomeMy WebLinkAbout04. Lower Walnut Creek Flood Protection and Habitat Restoration ProjectA-. Lower Walnut Creek Flood Protection and Habitat Restoration Project: Phase 1 - Project Visioning and Restoration Implementation EPA San Francisco Bay Water Quality Improvement Fund Initial Proposal April 30, 2014 SAN FRANCISCO ESTUARY PARTNERSHIP SAN FRANCISCO BAY WATER QUALITY IMPROVEMENT FUND INITIAL PROPOSAL I APRIL 2014 PROJECT SUMMARY Phase 1 of the Lower Walnut Creek Flood Protection and Habitat Restoration Project consists of a comprehensive visioning, planning, and public outreach effort for the entire project area and implementation of a significant component of the project: tidal marsh restoration at the mouth of Lower Walnut Creek, Basin 2 of Pacheco Marsh. Building on the EPA - funded "Flood Control 2.0" project, this proposed project will continue to advance the planning and implementation of innovative multi- objective flood control and habitat restoration projects in the Bay Area. INTRODUCTION The Walnut Creek watershed is the largest in Contra Costa County, draining over 150 square miles, and containing eight cities, several unincorporated communities, and over 300,000 residents. The lowest, or most downstream, portion of the watershed is called Lower Walnut Creek, and consists of a wide trapezoidal earth channel with levees on one or both sides approximately 3 miles in length. The channel is heavily impacted by sediment and has partially silted up, which affects its flood carrying capacity. However, simply removing the sediment with traditional removal methods negatively impacts habitat and wildlife associated with the channel and also is a short term solution, as the sediment quickly returns. The long -term vision for the area is to have a sustainable channel that provides critical flood protection while also providing important habitat for plants and animals, and regional trails for recreation. This will be achieved by moving back the channel levees in the lower reaches, or otherwise allowing flood waters to access the historic floodplain. The project is a rare opportunity to create Bay wetlands and riparian habitat on a major Bay Area stream. The Lower Walnut Creek Flood Protection and Restoration Project (LWC Project) incorporates a new way of approaching the traditional methods of operating and maintaining a flood control facility. This alternative approach moves away from the single purpose design to a sustainable plan that will increase flood protection while accommodating sediment and increasing habitat, including improving fish passage. At a cost of $15 -$20 million to build the complete LWC Project, the Contra Costa County Flood Control and Water Conservation District (CCCFCWCD) recognizes the need to undertake the project in phases, while simultaneously planning for a comprehensive, integrated project that meets multiple objectives. Under a previous EPA SFBWQIF grant, the multi- partner Flood Control 2.0 (FC2.0) project is creating regional tools for advancing multi - objective flood control and habitat restoration projects. Under that grant, $50,000 is allocated to the San Francisco Estuary Institute (SFEI) to work with CCCFCWCD to synthesize existing data and reports pertaining to the geomorphology and hydrology of the Walnut Creek flood control channel. This proposal builds on that foundational task by advancing the planning, design, public outreach, and implementation of the LWC Project. By having local flood protection and wastewater engineers working directly with the Regional Science Advisory Team convened under FC2.0 to re- envision the LWC landscape, we have the ability to create an ecosystem -based plan that is sufficiently practical to leverage substantial funding for integrated flood protection and ecosystem improvements. Lower Walnut Creek SAN FRANCISCO BAY WATER QUALITY IMPROVEMENT FUND INITIAL PROPOSAL I APRIL 2014 This project carries out the much - needed translation between regional ecosystem restoration and climate change adaptation goals, through complex multi- partner implementation. The San Francisco Estuary Partnership (SFEP) will provide overall project administration and assistance with project visioning and public outreach, and CCFCWCD will lead the implementation of the project. SFEI will provide science support, including developing information on the historical ecology of the Lower Walnut Creek area, facilitating science workshops to advance the LWC Project, and providing assistance with project monitoring. Other partners include East Bay Regional Park District, Muir Heritage Land Trust, Central Contra Costa Sanitary District, and the Walnut Creek Watershed Council. PROJECT ACTIVITIES The project has the following two objectives that will be developed concurrently: • Plan, design, and build a tidal marsh restoration project using FC2.0 tools that will inform the visioning and planning for the larger LWC Project • Conduct a visioning and planning effort for the LWC Project that will inform the restoration project and catalyze the next phases of restoration 1. Lower Walnut Creek Flood Protection and Habitat Restoration Project Visioning Lower Walnut Creek offers an exceptional opportunity within the region to restore tidal marshlands with a direct local freshwater and sediment supply, and within an ecologically critical and under - supported portion of the estuary. To successfully achieve this potential will require developing an ecosystem -based vision for integrating wetland restoration, flood protection, wastewater reuse, and recreation into an integrated, resilient landscape. A key part of the project therefore will be to develop a vision for the larger LWC Project that will guide both the Phase 1 Pacheco Marsh restoration and the subsequent phases. The Visioning task will build on the successful process developed in FC2.0 and most recently demonstrated on Novato Creek in Marin County, which brings together regional science experts with local managers and appropriate data. While existing FC2.0 funding will support an initial "brainstorming" workshop for Lower Walnut Creek, the proposed project will produce an actionable conceptual plan with additional science support and a resulting report. Regional conceptual models for flood control channels that integrate historical ecology and sediment analyses that are currently being developed under FC2.0 will be leveraged to inform the conceptual design for Lower Walnut Creek. Broad partner engagement in the process will include active participation and some matching funds from a variety of companies, organizations and agencies, including Muir Heritage Land Trust, East Bay Regional Park District (EBRPD), Central Contra Costa Sanitary District, the Walnut Creek Watershed Council, and Tesoro Refinery. Furthermore, CCCFCWCD will contribute over $300,000 to the public outreach and community-based planning process, ensuring that the resulting vision is not only scientifically sound but broadly supported. SAN FRANCISCO BAY WATER QUALITY IMPROVEMENT FUND INITIAL PROPOSAL I APRIL 2014 2. Lower Walnut Creek Historical Ecology Study Engineers, planners, and conservationists in central Contra Costa County have voiced a need for detailed historical information to improve environmental management activities in this region and to inform long -term solutions. Historical ecological data improve understanding of current landscape processes, offering a new set of tools to scientists and managers charged with designing tomorrow's resilient, sustainable systems. Historical ecology also helps build a deeper connection to the local landscape, strengthening public engagement and stewardship. For the LWC Project, there are no local examples of how stream and riparian features connected to tidal channel networks, tidal marshlands, and natural levees to guide this type of innovative project and allow it to maximize habitat restoration. To fill this information need, the study will develop a picture of Lower Walnut Creek as it functioned under more natural conditions and analyze how it provided desired ecological and hydrological functions. The project will create maps and graphics showing the extent and spatial relationships of riparian and Bay habitats, describing key ecological linkages and connectivity; the position, shape, length, and size of tidal channels connecting to the creek; and channel cross - sectional specifications. It also aims to generate public interest in watershed planning activities, providing a communication and education tool for interfacing with the public. The Historical Ecology Study will be funded by Central Contra Costa Sanitation District and the Mountain View Sanitary District as match for the project. 3. Walnut Creek Tidal Marsh Restoration Project (Pacheco Marsh Basin 2) Based on the data and vision developed in Tasks 1 and 2, the project will implement Phase 1 of the LWC Project; a strategically significant restoration of marsh at the mouth of Walnut Creek. Pacheco Marsh was historically part of a broad band of coastal brackish marsh along the southwestern portion of Suisun Bay near Carquinez Strait A network of tidal channels conveyed water, sediment, and nutrients from Suisun Bay onto the marshplain and supported natural tidal marsh functions. Prior to human intervention, Walnut Creek Channel (then Pacheco Slough) was a narrow tidal slough. By the late 1950s, constructed levees had eliminated tidal inundation onto the northern portion of the site. Additional levees were constructed in the late 1960s around the perimeter of the 120 -acre Pacheco Marsh and the site was used to receive dredge material from the flood control project along Walnut Creek Channel, substantially raising ground elevations. CCCFCWCD acquired the Pacheco Marsh property in 2002, in partnership with the Muir Heritage Land Trust and the EBRPD. As stated in the Memorandum of Understanding between these agencies, the main goal of the acquisition is to restore wetland and wildlife habitat while accommodating the existing uses of the site and planning for future recreation projects. According to analyses done by SFEI for the Baylands Ecosystem Habitat Goals Climate Change Update, the marshes along the Walnut Creek shoreline are one of only four patches of tidal marsh in San Francisco Bay larger than 1000 ha, and the only one adjacent to Suisun Bay in the brackish part of the estuary. Tidal marsh restoration in this part of the estuary has received less Lower Walnut Creek SAN FRANCISCO BAY WATER QUALITY IMPROVEMENT FUND INITIAL PROPOSAL I APRIL 2014 attention than the South Bay or San Pablo Bay, but is particularly important because of its ecologically significant location. The 1999 Baylands Goals Project identified the significance of restoring marsh here to improve habitat for anadromous fishes, including migratory Sacramento River salmon, as well as endangered Clapper Rails, and to increase the detrital input to the low- salinity zone recognized as essential for Delta smelt. In 2004, Phil Williams and Associates prepared a Pacheco Marsh Restoration Plan for the Muir Heritage Trust and CCCFCWCD. The report details site conditions, and for planning purposes divides the property into four sub - basins. The report evaluates several restoration alternatives for the four sub - basins and provides greater detail for the preferred alternative. The preferred alternative, based on both ecological value and cost, is a combination of tidal marsh and transitional and upland habitats. For Basin 2 specifically, the preferred alternative consists of creating 21 acres of habitat. The exact acreage of each habitat type will be determined during the final design process. This first phase is highly achievable and, while the acreage size is not as large as is possible in some other areas, it is highly strategic. Restoration of Pacheco Marsh Basin 2 will greatly improve the connectivity between portions of marsh on either side of Walnut Creek, contributing to an important corridor along the salinity gradient for species movement in response to changing salinity conditions. The project increases the resilience of the Bay ecosystem to climate change in multiple ways. The marsh is well located adjacent to Walnut Creek, a stream with a substantial sediment supply, which will help the marsh be resilient to sea level rise. Restoration of marshes in the brackish part of the estuary is also extremely important for overall estuary adaptation, as salt marshes will need to move up- gradient to maintain appropriate conditions. Pacheco Marsh offers a unique opportunity to incorporate treated effluent from the Central Contra Costa Sanitary District outfall pipeline that runs through the marsh to create freshwater wetlands within the site, particularly at the higher elevations where excavation costs are high. Design of the Basin 2 restoration project will allow for future opportunities to integrate treated effluent from the pipeline. The restoration of Pacheco Marsh Basin 2 also provides a significant opportunity for greater public awareness of and involvement in the entire LWC Project. As part of the restoration of Basin 2, the CCCFCWCD is partnering with Muir Heritage Land Trust to create a small area for parking, trail staging and public education. The staging area at the south end of Basin 2 would provide connections to the planned development of the EBRPD's Iron Horse Trail along Walnut Creek (a multi -use, whole- access trail between the cities of Concord and Dublin) and the planned Delta Trail (linking the San Francisco Bay Trail system to the planned Sacramento River trails in Yolo and Sacramento Counties). Public access to the Pacheco Marsh restoration site will provide the CCCFCWCD and the Muir Heritage Land Trust with opportunities to engage the public in the project and build public excitement and support for future phases. The CCCFCWCD intends to further engage the public in monitoring and stewardship of the project, through the Contra Costa Volunteer Creek Monitoring Program (a time - tested comprehensive volunteer bioassessment program) and through a partnership with the New Leaf Leadership Lower Walnut Creek SAN FRANCISCO BAY WATER QUALITY IMPROVEMENT FUND INITIAL PROPOSAL I APRIL 2014 Academy, an innovative program within a Martinez high school where students partner with community agencies to conduct wildlife monitoring and other environmental services. Implementation of the Pacheco Marsh Basin 2 project within the context of the entire LWC Project constitutes a critical first phase with short term outputs that will advance significant long term outcomes. The CCCFCWCD is highly motivated and committed to completing the LWC Project and will, with the coalition of project partners, provide both in -kind staff time and funds for construction as match. CLIMATE CHANGE Increased flooding due to elevated sea level and increasingly intensive storms from climate change requires increased need for flood protection in the Lower Walnut Creek area. Development of conceptual designs for the LWC Project will be informed by knowledge of existing and projected future risk from rising sea levels and increasing storm intensity, and will include a variety of adaptation strategies including moving back channel levees, reducing in- channel sedimentation and creation of riparian and tidal marsh habitats. The Pacheco Marsh Basin 2 restoration project will be designed to maximize adaptability of the site to increasing sea level. Unlike many potential restoration sites around the Bay, the historic use of the property for placing dredge material has produced "elevation capital" that allows for cost - effective adaptation to sea level rise without the need for placement of material to raise elevations. With the inherent flexibility provided by the high elevations of the site, the final designs will facilitate marsh establishment based on the most recent studies on elevation and restoration in the Bay. In addition, the project will create a sediment source for the marsh from Walnut Creek, allowing it to keep pace with rising sea levels. Finally, the project will create upland transition areas for high tide refugia for wildlife and additional room for marsh transgression. TIMEFRAME All project activities will be completed within four years. This includes the regional science forums, project vision and conceptual plan, public outreach and historical ecology for the Lower Walnut Creek Project. Final design, permitting and implementation of the Pacheco Marsh Basin 2 Restoration Project will be completed, as well as one year of post - project monitoring. RELATIONSHIP TO EXISTING PLANS The project supports implementation of several objectives and actions in the CCMP: Aquatic Resources Objective AR -4, Action AR -4.10; Wildlife Objective WL -1, Actions WL 1.1, WL -1.4; Wetlands Management Objective WT -1, Action WT -1.3; Wetlands Management Objective WT -4, Actions WT -4.2, WT -4.3; Wetlands Management Objective WT -5, Action WT -5.1; Pollution Prevention Objective PO -4, Actions PO -4.1, PO -4.2, and PO -4.3. The project also supports implementation of the San Francisco Bay joint Venture's Implementation Strategy, the Baylands Ecosystem Habitat Goals and forthcoming Climate Change Update, and the Bay Area Integrated Regional Water Management Plan. Lower Walnut Creek SAN FRANCISCO BAY WATER QUALITY IMPROVEMENT FUND INITIAL PROPOSAL I APRIL 2014 ENVIRONMENTAL RESULTS (OUTPUTS /OUTCOMES) OUTPUTS AND OUTCOMES SUMMARY TABLE OUTPUTS • Technical Memorandum from science workshop with initial evaluation of potential for recovering Bay habitats and functions in the Lower Walnut ' Creek project • Community outreach materials/ public workshop summary covering Science Workshop and Historical Ecology • Website, brochures, newsletter and other public outreach materials • Educational materials (i.e., interpretive panels) at Pacheco Marsh site • Summaries from 4 -6 public workshops • Well- illustrated, publicly accessible vision and conceptual plan for an integrated, resilient landscape for Lower Walnut Creek Project • GIS layers depicting historical channel alignment and floodplain • characteristics for lower Walnut Creek • Final design and engineering plans for Pacheco Marsh • Permits for Pacheco Marsh project • Approved QAPP for Pacheco Marsh project OUTCOMES SHORT -TERM (1-4 years) 21 Acres of new habitat consisting of tidal marsh, adjacent transitional habitat and upland habitat supporting several threatened and endangered species including the Salt - marsh harvest mouse, California Black Rail and California Clapper Rail Existing tidal marshes connected to new, high elevation tidal marsh with adjacent upland transition zone providing high tide refuge and sea level rise resilience. Staging area (up to 200' x 200') for parking and public education /outreach • Increased public awareness and support for Lower Walnut creek project through public access, citizen monitoring and partnership with local schools • Site preparation including excavation of dredge material, grading, channel • excavation, levee lowering, and revegetation • Pre- and post - project monitoring /assessment using EPA - supported tools such as CRAM and EcoAtlas • At least 30 students and volunteers actively monitoring site for one year post - project • Application of regional Flood Control 2.0 approaches and tools to one of the largest Bay Area watersheds Lower Walnut Creek Increased delivery of marsh productivity to the Suisun Bay low salinity zone, supporting native fisheries LONG -TERM (5 -10 years) • Increased flood protection and sediment trapping to keep pace with sea level rise • Restoration and increased flood protection for over 3 miles of Lower Walnut Creek, including restoring or enhancing 400 acres of tidal marsh, upland transition zone, and riparian habitat • Increased long term resilience to climate change for the Lower Walnut Creek area through restoring multiple, connected tidal marshes with direct fluvial sediment input • Restoration of key estuarine ecological processes (e.g., sedimentation, nutrient exchange) by increasing connectivity between a major Bay Area stream, tidal marshes, and the Bay • Opportunities for increased fresh and brackish marsh habitat using treated effluent • Reduction in effluent and nutrient discharge to Bay • Reduction of sediment input and heavy metals from flood flows through increased tidal marsh acreage SAN FRANCISCO BAY WATER QUALITY IMPROVEMENT FUND INITIAL PROPOSAL I APRIL 2014 The LWCFPHRP encompasses the current and historical Walnut Creek floodplain downstream of Highway 4. In phase I, tidal marsh will be restored at Pacheco Marsh. Lower Walnut Creek l ,on r. � \toad Pacheco �Pa����Fta j A Marsh 11 - � ".�. -'.� vro° Proposed Parking 8 4 Future Trail Staging Area Bay Trall , _ Tesoro , r♦ n &�` od Refinery t <. � fine ' -W r� t+ Acme Future EBRPD Landfill i Iron Horse Trail Extension it - "_-• ' IT Baker r °tea r Lower Walnut Creek Restoration — Promect Benefits - Enhanced flood protection - Improved aquatic, riverine, and marsh habitat - Expanded recreation opportunities Legend FCD Right of Way Channels to be removed from Corps system ' +- Highways Flood Control a _ CCCSD Treatment CO Plant 5 9 Existing End Iron of Iron Horse Trail ,a mD 1 isae i 4 r, 1 3 � a a a�N s A Y C t • < ° O 1 � m gq Q vi1 2 O W ¢ U V n U u