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Frequently Asked Questions

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Q: What is the South San Francisco Bay Shoreline Study?

A: The South San Francisco Bay Shoreline Study is a Congressionally authorized study by the U.S. Army Corps of Engineers together with the Santa Clara Valley Water District and the State Coastal Conservancy to identify and recommend flood protection and ecosystem restoration projects in South San Francisco Bay for Federal funding. The Corps is considering projects that will reduce flood risk, restore ecosystems and provide related benefits like recreation and public access.

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Q: Why is the Shoreline Study being conducted?

A: Santa Clara County’s shoreline is at great risk from flooding now due to extreme storm events combined with high tides, and in the future due to sea level rise. In their recently released California's Flood Future” Report, the California Department of Water Resources and the U.S. Army Corps of Engineers identified Santa Clara County, along with Los Angeles and Orange Counties, as having the highest potential damages from flooding in the state. Portions of Santa Clara County nearest the Bay are below sea level, and many high-tech companies are located along the shoreline, along with residents and the largest Water Pollution Control Plant in the Bay Area, which serves more than 1 million people (this map shows Silicon Valley inundation risks with potential sea level rise).

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Q: How could climate change affect the South Bay?

A: Global climate change has the potential to impact the South Bay because one of the expected results of climate change is sea level rise. The Shoreline Study is the first study of its kind in the Bay Area to develop a concrete plan to provide flood risk management in light of sea level rise in the Bay.

The science dealing with sea level rise has rapidly developed over the past few years as scientists have produced numerous studies. The Shoreline Study team is using a range of projections from the historic rate of sea level rise to over 2 feet of sea level rise by the year 2067 in assessing South Bay flood risk.

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Q: What geographic area does the Shoreline Study cover?

A: The study assessed flood risk damages for all Santa Clara County baylands, from Palo Alto to Southern Alameda County. It also considered restoration of former salt ponds within the Alviso Pond complex and adjacent properties such as areas around Moffett Field.

The study is being conducted in phases. The current phase focuses on the section of the Santa Clara County shoreline that will exhibit the greatest flood risk in the future due to sea level rise: the north San Jose shoreline area between Alviso Slough and Coyote Creek, which includes the Alviso community and the San Jose/Santa Clara Water Pollution Control Plant (see map). Known within the Shoreline Study as Economic Impact Area 11, or EIA 11, it includes homes, commercial and industrial facilities generally located below sea level and protected by salt pond levees. Planning for EIA 11 would enhance flood risk management for an area with high potential for future flood damage and allow wetland restoration to occur nearby by breaching salt pond levees. The proposed levees would also protect several high tech businesses and the new Silicon Valley Advanced Water Purification Center.

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Q: When is the project going to be built?

A: The draft Feasibility Study and environmental impact statement are due to be released to the public in Fall/Winter 2013. The release will be followed by a public comment period and public meetings. The final reports are scheduled for release in 2014. If the feasibility study recommends a project, it would go to Congress. Once Congress authorizes a project and appropriates funds, detailed design of project features could begin, possibly as soon as 2015, and construction could begin in 2017 at the earliest. The Santa Clara Valley Water District’s Safe Clean Water measure, passed in 2012, includes $15 million to share project construction costs. Once the report goes to Congress, partners will begin studying possible projects in other parts of Santa Clara County with high expected flood-related economic damages, such as parts of Palo Alto, Sunnyvale and Mountain View.

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Q: What about plans for other parts of Santa Clara County outside the Alviso area?

A: The Santa Clara Valley Water District’s Safe Clean Water measure, passed in 2012, includes $5 million to share the cost with the Corps of Engineers to study additional Economic Impact Areas in the overall Shoreline Study, starting potentially in 2015.

The other shoreline areas with high economic impacts from coastal flooding include portions of Palo Alto, Mountain View, and Sunnyvale (see map).

Prior to starting the next phase of the Shoreline Study in 2015/2016, the Santa Clara Water District is analyzing the existing conditions along Palo Alto, Mountain View, and Sunnyvale’s shorelines in order to better scope the level of effort needed to address flood protection and habitat restoration in future phases of the Shoreline Study with the U.S. Army Corps of Engineers.

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Q: What are the goals and objectives of the Shoreline Study?

A: In a phased approach, the parts of Santa Clara County’s shoreline with the highest potential damages from flooding will be protected using a combination of flood protection levees and wetlands. This approach using natural infrastructure would provide increased flood protection and restored Bay habitats, as well as a flood protection system that can evolve in the future.

The first feasibility study for EIA 11 will identify and recommend flood protection projects that meet the following goals:

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Q: How much would the project cost?

A: The total cost for the flood levee and restoration for the Alviso area (EIA 11) is projected at just over $100 million. The non-Federal sponsors, the Santa Clara Valley Water District (SCVWD) and the State Coastal Conservancy, would need to provide 35% of that cost. Santa Clara County voters have already approved $15 million for implementing the Shoreline Study as part of SCVWD’s Safe Clean Water renewal ballot measure. Part of the value of the salt ponds lands, paid for with state funds, would count towards the non-Federal share as well.

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Q: What were the results of the Army Corps' flood risk modeling?

A: The Army Corps' economic analysis looked at the impact of flooding under three sea level change scenarios for 14 areas in Santa Clara County and southern Alameda County. Four areas indicated high levels of potential damages under all three sea level change scenarios. Two additional areas indicated high levels of potential damages under only the highest sea level rise scenario (see map).

Areas with Projected Annual Damages from Tidal Flooding

Area of South Bay Sea Level Rise Curve H Sea Level Rise Curve 1 Sea Level Rise Curve 3
Damage in Millions (in the year 2067)
EIA 2: Palo Alto, Matadero Creek to
Barron Creek
$1.8 $2.5 $17.4
EIA 3: Palo Alto, Barron Creek to
Adobe Creek
$1.2 $1.7 $17
EIA 7: Sunnyvale, Stevens Creek to Sunnyvale West Creek - Non-NASA $13.4 $15.9 $24.5
EIA 8: Sunnyvale     $22.1
EIA 11: Alviso, Guadalupe Creek to
Coyote Creek
$1.2 $2.5 $19
EIA 13: Fremont     $17.6

Equivalent annual damages are calculated by taking expected annual damages, converting them to a single present worth value, then amortizing them over the analysis period using the federal discount rate.


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Q: Does the Shoreline Study look at flooding from creeks and rivers?

A: The Shoreline Study focuses on managing tidal flood risk, but included an evaluation of combined flooding from extreme high tides and flooding from rivers or creeks due to storm events. Flood risk from individual creeks has been reduced by a number of existing projects in the area. In Santa Clara County, several streams carry runoff through the valley and north to San Francisco Bay. The two largest rivers — the Guadalupe River and Coyote Creek — have been retrofitted to provide flood risk management along their banks to most communities, including the community of Alviso in north San Jose.

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Q: Who is managing the project?

A: The Shoreline Study is funded by a partnership among the U.S. Army Corps of Engineers, the Santa Clara Valley Water District and the California State Coastal Conservancy. The U.S. Fish and Wildlife Service and City of San Jose are also involved in the planning process. The Corps and the SCVWD were active project management team members throughout the planning phase of the South Bay Salt Pond Restoration Project and the SCVWD remains an active management team member of the South Bay Salt Pond Restoration Project. Extensive coordination has occurred, and will continue to occur, between the two projects.

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Q: How do I find out more about the Shoreline Study?

A: There are a number of agencies involved in the project and you are free to telephone any of the project managers:

In addition, Shoreline Study partners will hold public meetings at key project milestones to present results and hear from interested stakeholders and other members of the public.

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Q: What sort of habitat restoration could the Shoreline Study project include?

A: Plans under study would restore up to 3.5 square miles of wetland habitat and add new public trails and recreation opportunities. We also plan to bring fill into the project area to create broad upland transition areas so that we can recreate a vanished resource: the gradual transition habitat from marshes to upland areas. All such areas around the Bay have been developed, so no transition habitat for wildlife remains.

This large area of wetlands will both provide much-needed wetland habitat for endangered species, migratory birds, and fish and other aquatic species, as well as aiding in flood protection for the South Bay.

Ecosystem restoration and flood risk management will go hand-in-hand in the Alviso area. For example, as salt-evaporation ponds are breached and opened to the Bay’s tides to create tidal marsh, levees located between newly created tidal marsh and Santa Clara County communities are likely to be replaced or upgraded to provide better flood protection. Conversely, construction of flood protection features adjacent to low-lying urban areas will allow for restoration of land on the bayside of these features.

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Q: Why is the Corps interested in ecosystem restoration?

A: Ecosystem restoration was designated as a primary mission area for the Corps in 1986, but the Corps has been involved in improving the environment since the passage of the National Environmental Policy Act in 1969. Corps ecosystem restoration projects include dam removals and modifications, fish-ladder installation, wetlands creation, and improvements along riparian corridors. In partnership with local agencies, the Corps has been involved in a large number of ecosystem projects across the nation, including the Louisiana Coastal Project and the restoration of the Florida Everglades. In Northern California, the Corps has co-sponsored projects such as Sonoma Baylands, Hamilton Wetlands, and the Napa Salt Marsh Restoration here in the Bay Area and the Yolo Basin Wildlife Area near Sacramento.

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Q: Tell me about the Shoreline Study's progress and timeline.

A. Shoreline Study Timeline:

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Q: How does the Shoreline Study relate to the South Bay Salt Pond Restoration Project?

A: The study shares common goals with the South Bay Salt Pond Restoration Project, such as tidal flood protection, wetland habitat restoration and wildlife oriented public access, education and recreation. The projects also share the same geographic focus. The projects are being coordinated and complement each other.

The Shoreline Study provides an opportunity to secure Federal funding to assist in implementing parts of the South Bay Salt Pond Restoration Project. If the Shoreline Study successfully results in a project authorized by Congress for construction, Federal funds would be leveraged with State and local funds to implement some or all of the actions also sought by the South Bay Salt Pond Restoration Project.

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Q: Will the Shoreline Study result in a different plan than the South Bay Salt Pond Restoration Project?

A: Project partners intend the plans to be fully complementary. The purposes of the Shoreline Study and the South Bay Salt Pond Restoration Project are similar: to develop plans that provide the greatest benefit to the Bay Area community, the State, and the nation. However, the emphasis of the Shoreline Study is to determine if there is a plan (and what the plan is) that represents the best investment of Federal dollars. This plan will help determine the degree of Federal investment in a project that could implement elements also sought by the South Bay Salt Pond Restoration Project.

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Q: What is the South Bay Salt Pond Restoration Project?

A: The South Bay Salt Pond Restoration Project is a collaborative effort among Federal, State and local agencies working with scientists and the public to develop a programmatic plan for habitat restoration, flood risk management and wildlife-oriented public access within the 15,100 acres of former Cargill industrial salt ponds in South San Francisco Bay. The State Coastal Conservancy, California Department of Fish and Game, and the U.S. Fish and Wildlife Service jointly manage the project in collaboration with the Army Corps of Engineers, Alameda County Flood Control District and the Santa Clara Valley Water District.

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