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Silicon Valley 2.0 - Climate Preparedness Gap Analysis

Shoreline and Riverine Flood Protection Infrastructure Sector 3

Shoreline and Riverine Flood Protection Infrastructure Sector

Introduction The shoreline and riverine flood protection infrastructure sector in Santa Clara County serves as a critical

line of defense against coastal and riverine flooding in the region. The region has a history of riverine

flooding, and under baseline conditions, the exposure of the county’s population and structural assets to

flooding events is significant. More than 100,000 people in the Santa Clara County region are exposed to

100-year flooding events and more than 600,000 are exposed to 500-year flooding events1.

Additionally, the total depreciated replacement value of structural assets in the county exposed to 100-

year flooding events exceeds $15 billion, and the value of structural assets exposed to 500-year flooding

events exceeds $80 billion.

As a result of climate change, both coastal flooding and riverine flooding are expected to intensify and

become more frequent in the county. Currently, various flood protection systems are in place in Santa

Clara County to mitigate both forms of flooding. These systems are owned and operated by various

local, state, and federal agencies, and fall into the following categories:

Engineered Flood Protection Structures (levees and floodwalls)

Non-Engineered Berms

Wetlands (natural, managed, and tidal wetlands)

This categorization of flood protection systems is based on the primary function of the systems. Figures

1 and 2 show the physical locations of the shoreline protection systems in the northern part of Santa

Clara County.

Each of the shoreline protection systems is described below in more detail.

Engineered Flood Protection Structures There are 2 types of engineered flood protection structures in Santa Clara County:

Levees

Engineered levees are a common form of river and coastal flood protection structures. The primary

purpose of levees is to prevent inland flooding from major storm events and extreme water levels that

may be accompanied by large, powerful waves. Levees are designed to meet specific criteria with

respect to freeboard (the distance between the levee crest and the 100-year extreme water level, with

1 State Flood Management Planning Program. (2013). California’s Flood Future: Recommendations for Managing

the State's Flood Risk. California Department of Water Resources. Retrieved from

http://www.water.ca.gov/sfmp/resources/Attachment_D_MapBook_San_Joaquin-Yuba.pdf

http://www.water.ca.gov/sfmp/resources/Attachment_D_MapBook_San_Joaquin-Yuba.pdf


4 Shoreline and Riverine Flood Protection Infrastructure Sector

Figure 1: Santa Clara County Shoreline Protection and Levee Infrastructure - East



Figure 2: Santa Clara County Shoreline Protection and Levee Infrastructure - West



wave run-up for coastal structures), embankment protection, embankment and foundation stability, and

settling. Levees are generally designed, at a minimum, to provide protection from 100-year coastal

and/or riverine flood events.

Flood walls

Flood walls are a vertical barrier designed to protect inland areas from flooding. Flood walls can be an

effective means of flood protection in areas that do not have a sufficient footprint to construct a levee.

The design standards for flood walls are similar to those of an engineered levee in that the critical

components are the amount of freeboard and overall stability.

As shown in Figures 1 and 2, engineered flood protection structures have primarily been constructed in

the urban parts of Santa Clara County along creeks that flow north into the San Francisco Bay.

Non-Engineered Berms Non-engineered berms are similar to engineered levees in appearance; however, there is a very notable

difference between the two. Non-engineered berms are typically not engineered to meet the design

criteria applicable to levees. The most common non-engineered berms in Santa Clara County are the

berms surrounding the former salt ponds in the Alviso Pond Complex. These berms are composed of

mounds of bay mud that have been excavated from the bay floor. While berms are typically not

designed to provide flood protection to inland areas, in Santa Clara County, the berms and the ponds

themselves do provide an ad hoc level of protection by acting as a substantial buffer between bay water

levels and waves and inland developed areas.

Wetlands There are several different types of wetlands in Santa Clara County, with the majority located in the

northern part where the shoreline is less urbanized. Based on the research conducted under the South

Bay Salt Pond Restoration Project, wetlands in Santa Clara County can be classified into various

categories such as tidal flats, tidal marshes, diked marshes, managed ponds, and treatment basins. The

value of wetlands for flood protection and wave dissipation purposes is currently not well understood in

Santa Clara County.

Subsequent sections in this chapter describe the various vulnerabilities faced by the shoreline and

riverine flood protection infrastructure sector as a result of climate change, and the extent to which

these vulnerabilities have been addressed by the sector in Santa Clara County.

Climate Change Vulnerabilities in the Shoreline and Riverine Flood

Protection Infrastructure Sector: The shoreline protection infrastructure sector in Santa Clara County is primarily vulnerable to two

climate change variables2:

changes in precipitation patterns

2 AECOM Sensitivity Analysis, 2013.



sea level rise accompanied by storm surge

For more information on the nature and projected trends in these variables, refer to the Silicon

Valley 2.0 Climate Variable Memorandum. The assets and services of the shoreline protection

infrastructure sector that are affected by these climate change variables, and the nature of impacts

on the assets and services are summarized below in Table 1:

Table 1: Climate Change Variables and Impacts Related to Shoreline and Riverine Flood Protection Infrastructure in the Santa Clara County Region

Climate Change Variable Assets/Services Affected Nature of Impact

Changes in precipitation patterns

Levees, flood walls - Temporary over-topping due to water level rise in creeks, resulting in flooding

- Loss of function due to physical damage, resulting in flooding

Sea Level Rise Berms, wetlands, levees, flood walls - Loss of function due to over-topping and permanent inundation, resulting in flooding

Sea Level Rise + Storm Surge Berms, wetlands, levees, flood walls - Loss of function due to over-topping and/or physical damage, resulting in flooding

Existing Efforts to Address Shoreline and Riverine Flood Protection

Infrastructure Sector Vulnerabilities to Climate Change: This section provides an overview of existing climate change preparedness efforts in the shoreline

protection infrastructure sector in Santa Clara County. The section is organized by climate change

variable and specific type of asset vulnerability. An overview of the asset vulnerability (e.g. loss of

function) is provided, followed by descriptions of the existing effort(s), the level of implementation (i.e.,

vulnerability assessment, risk assessment, strategy development, or strategy implementation), and the

responsible agencies.

Efforts Addressing Changes in Precipitation Patterns

Description of Flood Protection Systems Vulnerability

Most of the engineered flood protection systems in Santa Clara County have been built along-side

creeks that flow into the San Francisco Bay. Changes in precipitation patterns could impact the ability of

these structures to offer protection to surrounding areas.

Studies indicate that on average, the Bay Area will experience little annual change in total precipitation

by mid-century. However, despite no change in overall annual precipitation, models project significant

changes in seasonal precipitation patterns and the intensity of individual rain events in the region.

Specific quantitative information of projected changes in storm intensity for the Bay Area are not readily

available, but overall, the state is predicted to see 3-day maximum precipitation peak values increase by



10%-50% by mid-century3. Storm frequency is also predicted to increase. Storm events with a 0.01

probability of occurrence (a 100-year event) in the historical record are projected to become 10 times

more likely (a 10-year event) by mid-century34. These more frequent high-intensity storm events could

over-top levees and flood walls in some areas, as well as physically damage the structural integrity of

these flood protection systems. Additionally, low-lying areas near the Bay could suffer from increased

riverine flooding due to the backwater effect from increasing sea levels and storm surge. A further

complication is that many of the urban areas in Santa Clara near the Bay have subsided. Storm drain

systems in these areas rely on pump stations to pump the water into the channels that drain to the Bay.

The pump stations may be undersized to handle the increased pumping needs, and the channel capacity

may not be sufficient to handle the riverine flood flows they are conveying plus the pumped drainage

demand. This could lead to more low-lying area flooding in these areas.

Existing Climate Change Preparedness Efforts

During the preparation of this Gap Analysis, no initiatives related to riverine flood protection were

identified that explicitly address the potential for climate change-related changes in precipitation

including increased magnitude or intensity of riverine flooding.

Parallel Efforts with Potential Climate Change Preparedness Benefits

While no explicit climate change-focused initiatives were identified, there are existing flood protection

efforts within the county that will benefit from climate change preparedness and could be adapted to

specifically include climate change considerations.

Periodic Monitoring & Maintenance for Levees and Flood walls

Description: The Santa Clara Valley Water District’s (SCVWD’s) Stream Maintenance Program

includes a key component for ensuring levee safety for approximately 100 miles of levees along

local streams in Santa Clara County. This program was launched per the directives of Clean, Safe

Creeks, and Natural Flood Protection Plan in order to provide flood protection along miles of

creeks, and to care for these improvements through an aggressive maintenance program.

Measures for levee safety under this program include inspections of factors that can affect levee

integrity, such as overgrown vegetation, burrowing rodents and/or erosion. If a problem is

identified during an inspection, appropriate preventative measures are taken by the SCVWD to

ensure the safety of the levee, as well as nearby people and properties. Adequate levee

maintenance also ensures the District’s ability to access and service streams during an emergency,

such as a flood event.

Implementation level: Parallel Effort with Climate Change Preparedness Benefits

Relevant agencies: SCVWD

Documentation of efforts: – SCVWD Levee Safety Measures, 2013,

http://www.valleywater.org/Services/LeveeSafety.aspx

3,

4 Pierce, D.W, T. Das, D.R. Cayan, E.P. Maurer, N.L. Miller, Y. Bao, M. Kanamitsu, K. Yoshimura, M.A. Snyder, L. C.

Sloan, G. Franco, M. Tyree (2013). Probabilistic estimates of future changes in California temperature and precipitation using statistical and dynamical downscaling. Climate Dynamics 40(3-4), 839-856.

http://www.valleywater.org/Services/LeveeSafety.aspx



New Flood Protection Infrastructure Development & Existing Infrastructure Improvement

Description: The SCVWD continues to implement flood protection projects, often in partnership

with the U.S. Army Corps of Engineers (USACE), along the creeks for which it is responsible. Many

of these projects are planning for reinforcement of existing flood protection infrastructure, or the

construction of new flood protection infrastructure such as levees and flood walls. Examples of

flood protection projects that are currently in the pipeline are provided in the section on

documentation of efforts.

Implementation level: Parallel Effort with Climate Change Preparedness Benefits

Relevant agencies: SCVWD, USACE, Cities, Santa Clara County

Documentation of efforts: Specific examples of creek flood protection projects are listed below,

along with project descriptions and online links to project details.

Table 2: Creek Flood Protection Projects

Project Name Project Description Project Link

Coyote Creek Flood Protection (Planning Study Phase)

This project aims to provide protection to surrounding areas from 100-year flood events on Coyote Creek

http://www.valleywater.org/services/CoyoteCreek.aspx

Upper Guadalupe River Project

This project aims to provide protection to 7,500 homes along a 5.7 mile stretch of the Guadalupe river from 100-year flood events.

http://www.valleywater.org/Services/GuadalupeRiver.aspx

Lower Berryessa Creek Project

This project aims to provide protection to 3,400 homes, businesses, and schools in Milpitas and San Jose from 100-year flood events.

http://www.valleywater.org/services/LowerBerryessaCreek.aspx

Lower Llagas Creek Capacity Restoration Project

This project aims to maintain flood protection for residents, businesses, agricultural land, and the South County Regional Wastewater Authority along Lower Llagas Creek. In addition, the project will also address will address habitat protection, develop maintenance guidelines and restore the previous design capacity of the creek.

http://www.valleywater.org/Services/LowerLlagasCreekCapacityRestorationProject.aspx

Permanente Creek Flood Protection

This project aims to improve flood protection, erosion control, structural repair, sediment reduction, and habitat restoration in parts of Cupertino, Los Altos, and Mountain View along Permanente Creek.

http://www.valleywater.org/services/PermanenteCreek.aspx

Lower Silver Creek This project aims to provide flood protection from 100-year flood events from Coyote Creek to 3,800 homes and businesses, enhance native riparian and environmental habitat, improve creek maintenance and water quality, and increase opportunities for recreation.

N/A

Sunnyvale East and West Channels

This project aims to protect 1,618 homes and 47 acres of highly valuable industrial and government lands from 100-year riverine flooding events

http://www.valleywater.org/service/SunnyvaleEastandWest.aspx

Upper Llagas Creek This project aims to provide flood protection in the urban areas of Morgan Hill from 100 year storms, and agricultural areas of Gilroy and Morgan Hill from 10-year storms.

http://www.valleywater.org/Services/UpperLlagas.aspx


















Efforts Addressing Sea Level Rise and Storm Surge

Description of Flood Protection Systems Vulnerability

It is estimated that the San Francisco Bay Area will experience sea level rise amounting to 4-24 inches by

mid-century, and 16-66 inches by the end of the century5. Rising sea levels will be accompanied by more

frequent and intense storm surge, which will significantly affect the functionality of shoreline protection

systems in Santa Clara County.

For example, in the case of levees and flood walls, as sea level rises, the inundation associated with high

tide (also known as Mean Higher High Water, or MHHW) and inundation associated with 100-year

extreme water levels (also known as 100-year Stillwater Elevation or SWEL) also rise. As MHHW

increases in the tidal reach of rivers and sloughs, flood conditions upstream in riverine reaches also

worsen as water cannot drain as effectively to the Bay. This could result in a reduction or elimination of

the levee and flood wall freeboard, leading to an increase in the potential for overtopping and inland

inundation of the protected areas behind the levee or flood wall. The list below presents the progression

over time of the vulnerability of coastal levees and floodwalls as sea level rises, assuming no upgrades

occur:

• The 100-year SWEL and the maximum wave run-up associated with that SWEL do not overtop the levee/flood wall, but the structure no longer meets its original freeboard design criteria.

• The 100-year SWEL is below the levee/flood wall crest, but the combination of the 100-year SWEL and the maximum wave run-up condition results in overtopping; therefore, overtopping occurs primarily during extreme events with large waves.

• The 100-year SWEL is above the levee/flood wall crest, resulting in overtopping. The levee would be routinely overtopped during extreme high-water events regardless of the wave conditions.

• MHHW is above the levee/flood wall crest, resulting in routine overtopping6.

In addition to overtopping, storm surge accompanying sea level rise can also result in erosion along the

levee crest and the backside of the levee, thus weakening the levee and increasing the potential for

levee failure.

Similarly, non-engineered berms are extremely vulnerable to sea level rise and storm surge. Berms are

typically maintained by the excavation of mud at the bay floor, directly adjacent to the berms. Many of

these adjacent borrow pits are already very deep; therefore, this source of material could be exhausted

over time, requiring suitable material to be imported. Due to the non-engineered nature of these

structures, there may also be a maximum height limit to which they can be built, thereby making them

vulnerable to over-topping and physical damage.

5 http://scc.ca.gov/files/2013/04/2013_SLR_Guidance_Update_FINAL.pdf

6 Please note that this list does not account for the progression of vulnerabilities of riverine levees.



Lastly, wetlands are also vulnerable to sea level rise. While wetlands have kept pace with historical

rates of sea level rise in the bay through accumulation of sediment and organic material, it is not clear if

wetlands will keep pace with accelerated rates of sea level rise in the future. For most wetlands in the

San Francisco Bay, there is no inland space for landward migration of the wetland. The wetlands along

the Santa Clara County shoreline will either keep pace with sea level rise or they will drown and

disappear, unless provision is made for their landward migration. Fringing wetlands directly outboard of

developed areas are at greatest risk of disappearing.

Existing Climate Change Preparedness Efforts

A diversity of initiatives are underway to protect the region’s social, ecological, and economic assets

from future sea level rise and the associated increases in storm surge. Initiatives that are explicitly

related to shoreline protection infrastructure as described first, followed by discussion of closely related

efforts that include sea level rise and storm surge mapping and other relevant studies.

New Flood Protection Infrastructure Development (Regional)

Description: The USACE is collaborating with the SCVWD and the California Coastal Conservancy

on the South San Francisco Bay Shoreline Study, which aims to identify and recommend flood risk

management and ecosystem restoration projects along South San Francisco Bay for federal

funding. The goal of the Shoreline Study is to protect the parts of Santa Clara County’s shoreline

with the highest potential damages and threats to human health and safety from flooding by using

a combination of levees and wetlands.

Implementation level: Adaptation Strategy Development

Relevant agencies: USACE, SCVWD, California Coastal Conservancy

Documentation of efforts: South San Francisco Bay Shoreline Study, 2013,

http://www.southbayshoreline.org/about.html.

New Flood Protection Infrastructure Development (Local)

Description: The City of Mountain View has collaborated with various consulting companies to

develop the Shoreline Regional Park Community Sea Level Rise Study Feasibility Report and

Capital Improvement Program. This document provides of an overview of Shoreline Community

vulnerability to sea level rise, proposed projects to provide long-term flood protection, and

estimates of future funding needed to implement these projects, many of which include

improvements to existing levees flood walls and tide gates.

Implementation level: Vulnerability Assessment and Adaptation Strategy Development

Relevant agencies: City of Mountain View

Documentation of efforts: Shoreline Regional Park Community Sea Level Rise Study Feasibility

Report and Capital Improvement Program, 2012,

http://laserfiche.mountainview.gov/Weblink/ElectronicFile.aspx?docid=64135&&&&&dbid=0.

Institutionalization of Climate Change Considerations into Regional Planning

Description: The San Francisco Bay Conservation and Development Commission (BCDC) updated

the San Francisco Bay Plan in October 2011 to deal with the expected impacts of climate change

in San Francisco Bay. The new requirements under the amended plan include risk assessments

http://www.southbayshoreline.org/about.html

http://laserfiche.mountainview.gov/Weblink/ElectronicFile.aspx?docid=64135&&&&&dbid=0



for large shoreline development projects, and the incorporation of sea level rise projections in

these risk assessments. Other requirements include designing new shoreline protection systems

when appropriate, preserving public access, protecting ecosystems and undeveloped areas,

encouraging resilient development, and developing a regional strategy.

Implementation level: Adaptation Policy and Implementation

Relevant agencies: BCDC

Documentation of efforts: San Francisco Bay Plan, 2011,

http://www.bcdc.ca.gov/laws_plans/plans/sfbay_plan.shtml.

Regional Climate Change Adaptation Plan Development

Description: BCDC developed a report in 2009, called Living with a Rising Bay: Vulnerability and

Adaptation in San Francisco Bay and on the Shoreline. This report provides extensive back

ground information on the scientific research on climate change, and includes maps depicting

the low-lying areas around the Bay that could impacted by future flooding from sea level rise

and storm surge. It assessed the sensitivity, adaptive capacity and vulnerability of three

systems: the shoreline environment, the Bay ecosystem and governance. Lastly this report

identified potential adaptation strategies to address key vulnerabilities, which include the

construction of shoreline protection systems when appropriate.


Relevant agencies: BCDC

Documentation of efforts: Living with a Rising Bay: Vulnerability and Adaptation in San Francisco

Bay and on the Shoreline, 2009, http://www.bcdc.ca.gov/BPA/LivingWithRisingBay.pdf.

Tidal Marshes/Wetlands Vulnerability Model

Description: An assessment of the vulnerability of tidal marshes/wetlands has been conducted by

PRBO Conservation Science, which indicates that it is unlikely that Bay Area marshes will be able

to keep pace with anticipated sea level rise at the end of the century. This study and the

accompanying model provide insights on prioritizing wetland restoration and conservation efforts.


Relevant agencies: - PRBO Conservation Science

Documentation of efforts:

o Stralberg D, Brennan M, Callaway JC, Wood JK, Schile LM, et al. (2011)

Evaluating Tidal Marsh Sustainability in the Face of Sea-Level Rise: A Hybrid

Modeling Approach Applied to San Francisco Bay. PLoS ONE 6(11): e27388.

doi:10.1371/journal.pone.0027388

San Francisco Bay Area Coastal Hydrodynamic and Wave Modeling

Description: The Federal Emergency Management Agency (FEMA) is leading the San Francisco Bay

Area Coastal Study, which aims to conduct coastal engineering and shoreline mapping of all

counties in the Bay Area, including Santa Clara County. This study will include hydrodynamic and

wave modeling, as well as a coastal analysis to estimate wave run-up, overtopping, and overland

wave propagation.

http://www.bcdc.ca.gov/laws_plans/plans/sfbay_plan.shtml

http://www.bcdc.ca.gov/BPA/LivingWithRisingBay.pdf



Implementation level: Climate Variable Data Development

Relevant agencies: FEMA

Documentation of efforts: San Francisco Bay Area Coastal Study, 2013,

www.r9map.org/Pages/San-Francisco-Coastal-Bay-Study.aspx

Sea Level Rise and Coastal Flooding Data and Data-Sharing

Description: The NOAA Coastal Services Center (NOAA CSC) has initiated an effort called The

Digital Coast, which is a repository of information relevant to coastal resource managers. It

consists of geospatial data, tools, and training materials created and gathered by various

agencies and made available to users through an Internet platform. One example of resources

provided under this effort is the Sea Level Rise and Coastal Flooding Impacts Viewer, which

shows how various levels of sea level rise will impact coastal communities.

Implementation level: Exposure and Vulnerability Assessment

Relevant agencies: NOAA, Coastal Service Center


o The Digital Coast, 2013, http://csc.noaa.gov/digitalcoast/

Sea Level Rise and Storm Surge Data and Data-Sharing

Description: Multiple agencies responsible for coastal management have formed a collaborative

project called Our Coast Our Future (OCOF), which is a user-driven effort focused on providing

coastal resource and land use managers/planners in the San Francisco Bay Area with locally

relevant, online maps and tools to help understand, visualize, and anticipate vulnerabilities to

sea level rise and storm surge within the bay. Note that the Silicon Valley 2.0 project will be

using sea level rise and storm surge map outputs from OCOF.

Implementation level: Climate Variable Data Development, Exposure Assessment, and

Vulnerability Assessment

Relevant agencies: Point Blue Conservation Science, The Gulf of the Farallones National Marine

Sanctuary, NOAA CSC, the U.S. Geological Survey (USGS) Pacific Coastal and Marine Science

Center, Coravai, National Estuarine Research Reserve System, San Francisco Bay National

Estuarine Research Reserve, Bay Area Ecosystems Climate Change Consortium, National Parks

Service, Ecosystem-Based Management Tools Network.


o Our Coast Our Future, 2013, http://data.prbo.org/apps/ocof/

Parallel Efforts with Potential Climate Change Preparedness Benefits

Natural coastal ecosystems have the potential to serve significant role in mitigating the impact of sea

level rise and storm surge in the Santa Clara County region. While the South Bay Salt Pond Restoration

Project is not an explicit climate change preparedness initiative, the project is critically important to sea

level rise planning efforts in the South Bay area.

South Bay Salt Pond Restoration Project

Description: The California Department of Fish and Game (CDFG), the U.S. Fish and Wildlife Service

(USFWS), and the California Coastal Conservancy have launched the South Bay Salt Pond

http://www.r9map.org/Pages/San-Francisco-Coastal-Bay-Study.aspx

http://csc.noaa.gov/digitalcoast/

http://data.prbo.org/apps/ocof/



Restoration Project, which aims to restore 15,100 acres of industrial salt ponds to a mosaic of tidal

wetlands and other habitats. This is the largest tidal wetland restoration project on the west

coast, and when completed, will provide flood protection to parts of Santa Clara County. The

restoration project could benefit climate preparedness efforts by providing natural flood

protection systems.

Implementation level: Parallel Effort with Potential Climate Preparedness Benefits

Relevant agencies: The CDFG, the USFWS, and the California Coastal Conservancy

Documentation of efforts: The South Bay Salt Ponds Restoration Project, 2013,

http://www.southbayrestoration.org/Project_Description.html.

Key Actors and Decision Makers for Climate Change Adaptation Planning

and Implementation The shoreline and riverine flood protection infrastructure sector consists of a complex network of public

and private agencies, each of which will have a critical role to play in advancing climate change

adaptation planning. These agencies are identified below, along with a description of their roles.

Federal Regulatory Agencies:

USACE: This is a federal agency under the Department of Defense, which provides engineering

services to strengthen national security, energize the economy, and reduce risks from disasters.

USACE’s mission areas directly support coastal resilience through the construction and

maintenance of engineered flood protection systems, as well as the restoration of natural flood

protection systems such as wetlands. USACE recognizes that climate change variables such as

sea level rise, storm surge, and changes in precipitation directly affect their mission areas, and is

actively engaged in a variety of projects aimed at building coastal resilience in Santa Clara

County, which are described in previous sections.

NOAA CSC: The National Oceanic and Atmospheric Administration (NOAA) is a world leader in

coastal science and management. NOAA’s Coastal Services Center provides data, tools,

publications, and trainings to coastal communities on various stages of climate change

adaptation.

USGS: The USGS is a science organization that provides impartial information on various topics

such as ecosystem health, natural hazards, natural resources, and climate change. USGS

research is particularly vital to predicting the impacts of climate change on sea level, and

agencies in the Bay Area continue to rely on this research in their climate change adaptation

planning efforts.

FEMA: FEMA is responsible for coordinating the federal government’s role in preparing for,

preventing, mitigating the effects of, responding to, and recovering from disasters, including

those that are likely to increase in frequency or magnitude as a result of climate change.

US FWS: The US FWS is a bureau within the U.S. Department of the Interior, whose mission is to

conserve, protect and enhance fish, wildlife and plants and their habitats. In Santa Clara County,

the US FWH owns and operates a network of 25 salt ponds covering 8,000 acres, which offer

http://www.southbayrestoration.org/Project_Description.html



critical flood protection services. Future management decisions made by the US FWS will play

an important role in determining the resilience of Santa Clara County’s coastal zones.

State Regulatory Agencies

California Coastal Conservancy: The California Coastal Conservancy is a state agency that uses

entrepreneurial techniques to purchase, protect, restore, and enhance coastal resources, and to

provide access to the shore. This agency is a partner in ongoing adaptation-related studies in

Santa Clara County, which include the South Bay Salt Pond Restoration project and the South

San Francisco Bay Shoreline Study.

California Ocean Protection Council: The Council’s mission is to ensure that California maintains

healthy, resilient, and productive ocean and coastal ecosystems. Most recently, the Ocean

Protection Council has led the process of updating the State of California’s guidance on

incorporating sea level rise considerations into planning and decision-making for California.

CDFG: This state agency’s responsibility is to maintain native fish, wildlife, plant species and

natural communities for their intrinsic and ecological value and their benefits to people. This

agency is a core partner in the South San Francisco Bay Shoreline Study in Santa Clara County.

Regional Agencies

SCVWD: The district manages an integrated water resources system that includes water supply,

flood protection and stewardship of streams in Santa Clara County. One of the district’s core

responsibilities is to protect the county from flooding via ongoing stream maintenance and

construction of flood protection projects. The district’s role in flood protection projects is

described in more detail in previous sections.

BCDC: BCDC is the federally-designated state coastal management agency dedicated to the

protection and enhancement of San Francisco Bay and to the encouragement of the Bay's

responsible use. BCDC’s climate change program is responsible for promoting research on

climate change impacts, mitigation, and adaptation. The program is also responsible for

developing and implementing adaptation policies in coordination with regional partners, and

building the region’s institutional capacity to adapt to climate change. BCDC has jurisdiction

over a 100-foot shoreline band (i.e. an area that extends up to 100 feet from the bay), and in

turn, has permitting authority over existing and proposed land-use changes and structures

within this jurisdiction. BCDC plays a critical role in decision-making related to shoreline

protection infrastructure located in its jurisdiction.

Local Governments

Local governments have the ability to advance climate change adaptation planning at the

community scale. Local governments can incorporate climate change considerations into their

locally enforceable general plans. Santa Clara County and the cities within the county have

broad authority over shoreline land-use, and can use this authority to maintain/enhance the

functionality of flood protection systems in their jurisdiction.



Summary of Existing Efforts to Address Vulnerabilities Table 3 summarizes existing efforts in the shoreline and riverine flooding protection infrastructure

sector to address potential impacts of climate change on sector assets. Efforts to address climate

change impacts vary across the different agencies responsible for flood protection services in the

county. Most of the shoreline protection initiatives undertaken in the county to date are in the

vulnerability assessment and adaptation strategy development stages. Currently, very few initiatives

demonstrate actual implementation of climate change adaptation strategies. Barriers to strategy

implementation include lack of granular data on climate change impacts on shoreline protection

systems, financial constraints, and complex jurisdictional authority.

Table 3: Existing Efforts to Address Shoreline and Riverine Flood Protection Infrastructure Sector Climate Change Vulnerabilities

Climate Change Variable Asset

Macro-category of Effort Description of Effort

Climate Change

Preparedness Category Stakeholder

Changes in Precipitation

Levees, flood walls

Monitoring/ Maintenance

Periodic maintenance of levees and flood walls

Parallel Effort with Climate

Change Preparedness

Benefits

SCVWD


Levees, flood walls

New Flood Protection Infrastructure Construction

Planned construction of new flood protection systems under specific flood protection projects


Change Preparedness

Benefits

SCVWD


Levees, flood walls

Existing Flood Protection

Infrastructure Improvement

Planned improvements to existing flood protection systems under specific flood protection projects


Change Preparedness

Benefits

SCVWD

Sea Level Rise + Storm Surge

Levees, flood walls, wetlands


Planned construction of new flood protection systems under specific flood protection projects at the Regional Scale

Adaptation Strategy Planning

USACE, SCVWD, Coastal

Conservancy


Berms, levees, flood walls, wetlands


Planned construction of new flood protection systems under specific flood protection projects at the City Scale

Vulnerability Assessment and

Adaptation Strategy

Development

City of Mountain View



Policy/Planning/ Operations

Mainstreaming of climate change considerations into regional bay plans

Adaptation Policy and

Implementation

BCDC

Sea Level Rise + Berms, levees, flood walls,

Policy/Planning/ Development of a stand-alone Vulnerability Assessment and



Storm Surge wetlands Operations regional adaptation plan Adaptation Strategy

Development

BCDC

Sea Level Rise Wetlands Monitoring/ Measuring/

Maintenance

On-going research on anticipated responses of wetlands to sea level rise

Vulnerability Assessment and

Adaptation Strategy

Development

Point Blue Conservation

Science

Storm Surge Berms, levees,

flood walls, wetlands

Data Development

Hydrodynamic and wave modelling to estimate wave run-up, overtopping, and overland wave propagation

Climate Variable Data Development

FEMA



Data Development /Education/

Communication/ Outreach

Sea Level Rise and Coastal Flooding Data and Data-Sharing

Exposure and Vulnerability Assessment

NOAA



Data Development /Education/

Communication/ Outreach

Sea Level Rise and Storm Surge Data and Data-Sharing

Climate Variable Data Development,

Exposure Assessment,

and Vulnerability Assessment

OCOF

Sea Level Rise Wetlands Restoration of Natural

Flood Protection Systems

Planned restoration of salt-ponds to tidal wetlands and other habitats

Parallel Effort with Potential

Climate Preparedness

Benefits

CDFG, USFWS, Coastal

Conservancy

Summary of Existing Gaps in Climate Change Preparedness Efforts in the

Shoreline and Riverine Flood Protection Infrastructure Sector Table 4 provides a summary of existing efforts and gaps in the shoreline and riverine flood protection

infrastructure sector climate change preparedness efforts. Table 4 lists the existing vulnerabilities of

various assets in this sector to climate change variables, along with an identification of whether climate

change preparedness efforts are in place to address these vulnerabilities, as well as a qualitative rating

of the level of those climate change preparedness efforts.

In summary, considerable effort is being made to assess the vulnerability of regional assets to sea level

rise and to identify effective climate preparedness strategies to mitigate its potential consequences. The

analysis did not identify any initiatives that have yet reached the implementation stage. Storm surge

climate variable data is currently being developed. This will allow more thorough understanding of the

implications of sea level rise for the region and will be useful in vulnerability and risk assessments and



the development of adaptation strategies. The gap analysis did not identify any initiatives related to

riverine flood protection that are explicitly looking at the potential impacts of climate change-induced

increases to the frequency and magnitude of riverine flooding in the county.

Table 4: Level of Climate Change Preparedness Efforts in the Shoreline and Riverine Flood Protection Infrastructure Sector

Climate Change Variable

Assets/Services Affected Nature of Impact

Existing Climate Change

Preparedness Efforts?

Level of Climate Change

Preparedness Efforts

Changes in precipitation patterns

Levees, flood walls - Temporary over-topping due to water level rise in creeks, resulting in flooding


No None, but Parallel Efforts Exist

Sea Level Rise Berms, wetlands, levees, flood walls

- Loss of function due to permanent inundation, resulting in flooding

Yes Medium

Storm Surge Berms, wetlands, levees, flood walls


Yes Low

shoreline and riverine flood protection infrastructure ... - shoreline protection...silicon valley...

Documents