FINAL

(Department of Homeland Security-FEMA Seal)

Programmatic Environmental 
Assessment (PEA) for Typical 
Recurring Actions

Flood, Earthquake, Fire, Rain, and 
Wind Disasters in California
Prepared for
Federal Emergency Management Agency
Region IX
1111 Broadway, Suite 1200
Oakland, California 94607
December 2003
 
[NISTAC Symbol]
Nationwide Infrastructure Support Technical Assistance Consultants
A Joint Venture of URS Group, Inc., and Dewberry & Davis LLC

500 12th Street, Suite 200
Oakland, California 94607

Contract No. EMW-97-CO-0173
Task Order 61

15293557.00100


Table of Contents
Section 1 ONE	Introduction	1-1
1.1	Disaster Programs	1-1
1.1.1	Overview		1-1
1.1.2	Response		1-1
1.1.3	Recovery		1-1
1.1.4	Prevention and Mitigation	1-2
1.2	Regulatory Background		1-2
1.3	The Programmatic Environmental Assessment	1-3
1.4	Actions Not Covered by this Programmatic Environmental Assessment	1-5
1.4.1	Statutory Exclusions	1-5
1.4.2	Categorical Exclusions	1-5
1.4.3	Actions Requiring an Environmental Assessment Instead of a Programmatic 
	Environmental Assessment	1-6
1.4.4	Actions Requiring an Environmental Impact Statement		1-6
1.5	Actions Covered by the Programmatic Environmental Assessment	1-6
1.6	Purpose of and Need for Action					1-6
1.7	California Environmental Quality Act and Applicable Permits	1-7
1.8	Using the Programmatic Environmental Assessment			1-7
1.8.1	Organization of the Programmatic Environmental Assessment	1-7
1.8.2	Use of the Programmatic Environmental Assessment		1-8
1.8.3	Other Complementary Programmatic Documents			1-8

Section 2 TWO	Description of Proposed Actions and Alternatives	2-1
2.1	No Action Alternative						2-2
2.2	Nonemergency Debris Removal					2-2
2.3	Constructing, Modifying, or Relocating Facilities		2-3
2.3.1	Upgrading or Otherwise Modifying Buildings			2-3
2.3.2	Providing Temporary Facilities					2-4
2.3.3	Acquiring and Demolishing Existing Facilities			2-4
2.3.4	Repairing, Realigning, or Otherwise Modifying Roads, Trails, Utilities, and Rail Lines
									2-5
2.3.5	Constructing New Facilities or Relocating Existing Facilities	2-5
2.3.6	Relocating the Function of an Existing Facility			2-6
2.3.7	Extending the Pressurized Water Service Area			2-6
2.3.8	Developing Demonstration Projects				2-6
2.4	Actions Involving Watercourses and Coastal Features		2-6
2.4.1	Repairing, Stabilizing, or Armoring Embankments			2-7
2.4.2	Creating, Widening, Clearing, or Dredging a Waterway		2-7
2.4.3	Constructing or Modifying a Water Crossing			2-8
2.4.4	Constructing or Modifying a Water Detention, Retention, or Storage Facility	2-9
2.4.5	Constructing or Modifying Other Flood Control Structures	2-10
2.4.6	Constructing or Modifying a Coastal Feature			2-10
2.5	Vegetation Management						2-10
2.5.1	Mechanical or Hand Clearing of Vegetation			2-11
2.5.2	Herbicidal Treatments						2-11
2.5.3	Prescribed Burns						2-12
2.5.4	Biological Control						2-12
2.6	Publication and Revision of Flood Insurance Rate Maps		2-12

Section 3 THREE	Affected Environment					3-1
3.1	Geology, Seismicity, and Soils					3.1-1
3.1.1	Regulatory Background						3.1-1
3.1.2	Geology, Geologic Hazards, and Soils in California		3.1-4
3.2	Air Quality							3.2-1
3.2.1	Regulatory Background						3.2-1
3.2.2	Air Quality in California					3.2-3
3.3	Water Resources							3.3-1
3.3.1	Regulatory Background						3.3-1
3.3.2	Discussion of Water Resources in California			3.3-5
3.4	Biological Resources						3.4-1
3.4.1	Regulatory Background						3.4-1
3.4.2	Biological Resources in California				3.4-5
3.5	Cultural Resources						3.5-1
3.5.1	Regulatory Background						3.5-1
3.5.2	Cultural Resources in California				3.5-3
3.6	Socioeconomics and Public Safety				3.6-1
3.6.1	Regulatory Background						3.6-1
3.6.2	Socioeconomic Conditions in California				3.6-2
3.7	Land Use and Planning						3.7-1
3.7.1	Regulatory Background						3.7-1
3.7.2	Land Uses in California						3.7-2
3.8	Public Services and Recreation					3.8-1
3.8.1	Fire Protection							3.8-1
3.8.2	Police Protection						3.8-2
3.8.3	Public Schools							3.8-2
3.8.4	Public Parks							3.8-2
3.8.5	Public Utilities						3.8-3
3.9	Transportation							3.9-1
3.9.1	Regulatory Background						3.9-1
3.9.2	Transportation in California					3.9-1
3.10	Noise								3.10-1
3.10.1	Regulatory Background						3.10-1
3.10.2	Existing Noise in California					3.10-3
3.11	Hazardous Materials and Wastes					3.11-1
3.11.1	Regulatory Background						3.11-1
3.11.2	Hazardous Materials and Wastes and the Affected Environment	3.11-3
3.12	Visual Resources						3.12-1
3.12.1	Regulatory Background						3.12-1
3.12.2	Visual Resources in California					3.12-1

Section 4 FOUR	Environmental Consequences of Actions and Alternatives	4-1
4.1	Geology, Seismicity, and Soils					4.1-1
4.1.1	No Action Alternative						4.1-1
4.1.2	General Consequences of Proposed Actions			4.1-1
4.1.3	Consequences Attributable to Specific Actions			4.1-1
4.2	Air Quality							4.2-1
4.2.1	No Action Alternative						4.2-1
4.2.2	General Consequences of Proposed Actions			4.2-1
4.2.3	Consequences Attributable to Specific Actions			4.2-2
4.3	Water Resources							4.3-1
4.3.1	No Action Alternative						4.3-1
4.3.2	General Consequences of Proposed Actions			4.3-1
4.3.3	Consequences Attributable to Specific Actions			4.3-2
4.4	Biological Resources						4.4-1
4.4.1	No Action Alternative						4.4-1
4.4.2	General Consequences of Proposed Actions			4.4-1
4.4.3	Consequences Attributable to Specific Actions			4.4-2
4.5	Cultural Resources						4.5-1
4.5.1	No Action Alternative						4.5-1
4.5.2	General Consequences of Proposed Actions			4.5-1
4.5.3	Consequences Attributable to Specific Actions			4.5-2
4.6	Socioeconomics and Public Safety				4.6-1
4.6.1	No Action Alternative						4.6-1
4.6.2	General Consequences of Proposed Actions			4.6-1
4.6.3	Consequences Attributable to Specific Actions			4.6-2
4.7	Land Use and Planning						4.7-1
4.7.1	No Action Alternative						4.7-1
4.7.2	General Consequences of Proposed Actions			4.7-1
4.7.3	Consequences Attributable to Specific Actions			4.7-1
4.8	Public Services and Recreation					4.8-1
4.8.1	No Action Alternative						4.8-1
4.8.2	General Consequences of Proposed Actions			4.8-1
4.8.3	Consequences Attributable to Specific Actions			4.8-1
4.9	Transportation							4.9-1
4.9.1	No Action Alternative						4.9-1
4.9.2	General Consequences of Proposed Actions			4.9-1
4.9.3	Consequences Attributable to Specific Actions			4.9-1
4.10	Noise								4.10-1
4.10.1	No Action Alternative						4.10-1
4.10.2	General Consequences of Proposed Actions			4.10-1
4.10.3	Consequences Attributable to Specific Actions			4.10-1
4.11	Hazardous Materials and Wastes					4.11-1
4.11.1	No Action Alternative						4.11-1
4.11.2	General Consequences of Proposed Actions			4.11-1
4.11.3	Consequences Attributable to Specific Actions			4.11-1
4.12	Visual Resources						4.12-1
4.12.1	No Action Alternative						4.12-1
4.12.2	General Consequences of Proposed Actions			4.12-1
4.12.3	Consequences Attributable to Specific Actions			4.12-1
4.13	Comparison of Environmental Consequences			4.13-1

Section 5 FIVE - Public Participation Process				5-1

Section 6 SIX -	References						6-1
6.1	Description of Proposed Actions and Alternatives (Section 2.0)	6-1
6.2	Geology, Seismicity, and Soils (Section 3.1)			6-1
6.3	Air Quality (Section 3.2)					6-3
6.4	Water Resources (Section 3.3)					6-4
6.5	Biological Resources (Section 3.4)				6-4
6.6	Cultural Resources (Section 3.5)				6-4
6.7	Socioeconomics and Public Safety (Section 3.6)			6-4
6.8	Land Use and Planning (Section 3.7)				6-4
6.9	Public Services and Recreation (Section 3.8)			6-4
6.10	Noise (Section 3.10)						6-5
6.11	Hazardous Materials (Section 3.11)				6-5
6.12	Visual Resources						6-6

Tables
3.1-1 	Geologic Hazards
3.1-2 	Notable California Earthquakes
3.1-3 	Explanation of Selected Soil Taxonomic Terms
3.2-1	Emission Thresholds That Trigger Applicability of the General Conformity Rule in Tons 
per Year Based on Air Quality Attainment Designation in California
3.2-2 	State and Federal Ambient Air Quality Standards
3.2-3 	North Coast Air Basin Attainment Status
3.2-4 	San Francisco Air Basin Attainment Status
3.2-5 	North Central Coast Air Basin Attainment Status
3.2-6 	South Central Coast Air Basin Attainment Status
3.2-7 	South Coast Air Basin Attainment Status
3.2-8 	San Diego Air Basin Attainment Status
3.2-9 	Northeast Plateau Air Basin Attainment Status
3.2-10 	Sacramento Valley Air Basin Attainment Status
3.2-11 	San Joaquin Valley Air Basin Attainment Status
3.2-12 	Great Basin Valley Air Basin Attainment Status
3.2-13 	Mojave Desert Air Basin Attainment Status
3.2-14 	Salton Sea Air Basin Attainment Status
3.2-15 	Mountain Counties Air Basin Attainment Status
3.2-16 	Lake County Air Basin Attainment Status
3.2-17 	Lake Tahoe Air Basin Attainment Status
3.3-1 	California Wild and Scenic Rivers
3.3-2 	California Watershed Hydrologic Areas
3.5-1 	Summary Descriptions of Cultural Resources Sites in California
3.6-1 	State and County Demographics
3.10-1 	Population Density and Average Day-Night Noise Levels Correlation
3.10-2 	Estimating Existing Noise Exposure
3.11-1 	California Asbestos NESHAP Air Pollution Control Districts
4-1 	Typical Construction BMPs
4-2	Impact Matrix of Actions and Alternatives by Resource Area

Figures
3.1-1 	California Geomorphic Provinces
3.1-2 	California Ecological Subregions
3.2-1 	California Air Basins
3.2-2 	California Air Districts
3.2-3 	California Counties
3.2-4 	South Coast Air Basin
3.3-1 	California Watersheds
3.3-2 	California Groundwater Basins


Appendices
A	Example of a Memorandum for an Action Where the PEA Is the Only Documentation 
	Necessary to Comply with NEPA

B	Example of a Supplemental Environmental Assessment

C	Memorandum of Understanding with the U.S. Fish and Wildlife Service

D	Agreement Regarding Section 7 Consultation on the Endangered Species Act When the 
	U.S. Army Corps of Engineers (USACE) Serves as Lead Agency

E	Programmatic Biological Opinion / Programmatic Incidental Take Statement for FEMA-
	1155-DR-CA

F	Programmatic Biological Assessment for the National Marine Fisheries Service

G	National Marine Fisheries Service Concurrence Letter

H	Programmatic Agreement with the California State Historic Preservation Officer (SHPO) 
	for Future Declared Disasters

I	List of Agencies to Receive Copies of Draft and Final Programmatic Environmental 
	Assessments

J	Comment Letters on the Draft PEA

K	Cumulative Public Notice Published for the FEMA 1203-DR-CA Disaster

Acronyms
ºF		°Fahrenheit
ACHP		Advisory Council on Historic Preservation
ACCM		asbestos-containing construction material
ACM		asbestos-containing material
A-P Act		Alquist-Priolo Earthquake Fault Zoning Act
APCD		Air Pollution Control District 
AQMD		Air Quality Management District
AST		aboveground storage tank
BACT		best available control technology
BFE		base flood elevation
BLM		Bureau of Land Management
BMPs		Best Management Practices
CAA		Clean Air Act
CAAQS		California Ambient Air Quality Standards 
Caltrans	California Department of Transportation
CARA		California River Assessment
CARB		California Air Resources Board
CBC		California Building Code
CCAA		California Clean Air Act 
CCR		California Code of Regulations
CDF		California Department of Forestry and Fire Protection
CDFG		California Department of Fish and Game
CEPA		California Environmental Protection Agency
CEQ		Council on Environmental Quality
CEQA		California Environmental Quality Act
CERCLA		Comprehensive Environmental Response, Compensation, and Liability Act
CESA		California Endangered Species Act
CFR		Code of Federal Regulations
CNEL		community noise equivalent level
CO		carbon monoxide
CTC		California Transportation Commission
CVP		Central Valley Project
CWA		Clean Water Act
DBA		a-weighted decibel(s)
DNL(Ldn)	day-night averaged sound level
EA		Environmental Assessment
EFH		Essential Fish Habitat
EIS		Environmental Impact Statement
EO		Executive Order
ESA		(federal) Endangered Species Act
FEMA		Federal Emergency Management Agency
FIRM		Flood Insurance Rate Map
FONSI		Finding of No Significant Impact
GCR		General Conformity Rule
HUD		Department of Housing and Urban Development
LBP		lead-based paint
Leq		equivalent sound level
MAF		million acre-feet
Mph		mile(s) per hour
NAAQS		National Ambient Air Quality Standards
NEHRP		National Earthquake Hazard Reduction Program
NEPA		National Environmental Policy Act
NESHAP		National Emission Standards for Hazardous Air Pollutants
NFIP		National Flood Insurance Program
NHPA		National Historic Preservation Act
NOAA Fisheries	National Marine Fisheries Service
NO2		nitrogen dioxide
NOx		nitrogen oxides
NPDES		National Pollutant Discharge Elimination System
NPS		National Park Service
NRCS		Natural Resources Conservation Service 
NRHP		National Register of Historic Places
NSR		New Source Review
O3		ozone
OES		California Office of Emergency Services
OPR		California Governor's Office of Planning and Research
PA		Programmatic Agreement
PBO		Programmatic Biological Opinion
PCBs		polychlorinated biphenyls
PEA		Programmatic Environmental Assessment
PG&E		Pacific Gas and Electric
PITS		Programmatic Incidental Take Statement
PL		Public Law
PM10		particulate matter smaller than 10 microns in diameter
PM2.5		particulate matter smaller than 2.5 microns in diameter 
PRC		Public Resources Code
PSD		Prevention of Significant Deterioration
RACM		regulated asbestos containing material
RCRA		Resource Conservation and Recovery Act
RWQCB		Regional Water Quality Control Board
SARA		Superfund Amendments and Reauthorization Act
SCE		Southern California Edison
SDG&E		San Diego Gas and Electric
SEA		Supplemental Environmental Assessment
SFHA		Special Flood Hazard Area
SHPO		State Historic Preservation Officer
SIP		State Implementation Plan
SMUD		Sacramento Municipal Utility District
SO2		sulfur dioxide
SWP		State Water Project
SWRCB		State Water Resources Control Board
TSCA		Toxic Substances Control Act
UBC		Uniform Building Code
URARPAPA	Uniform Relocation Assistance and Real Property Acquisitions Policies Act of 1970
USACE		U.S. Army Corps of Engineers
USC		United States Code
USEPA		U.S. Environmental Protection Agency
USFS		U.S. Forest Service
USFWS		U.S. Fish and Wildlife Service
UST		underground storage tank
VOCs		volatile organic compounds
WDRs		Waste Discharge Requirements

1. Section 1 ONE	Introduction
1.1 DISASTER PROGRAMS
1.1.1 Overview
The Federal Emergency Management Agency (FEMA) administers federal programs for 
response to, recovery from, and preparation for disasters. Disasters can result from natural 
events, such as floods, earthquakes, wildland fires, rains, and windstorms, or human-caused 
events, such as fires and explosions. FEMA administers these programs under the following 
authorities:
* The Robert T. Stafford Disaster Relief and Emergency Assistance Act, Public Law (PL) 
93-288, as amended (the Stafford Act), authorizes FEMA to administer response, recovery, and 
mitigation programs. The Stafford Act was amended by the Disaster Mitigation Act of 2000, PL 
106-390. The Stafford Act includes the following FEMA programs: the Public Assistance 
Program; the Hazard Mitigation Grant Program, pre-disaster mitigation programs, the Fire 
Management Assistance Grant Program, and the Assistance for Individuals and Households 
Program. The implementing regulations for these programs are found in Title 44, Code of 
Federal Regulations (CFR), Parts 204 and 206.
* The National Flood Insurance Act, as amended, PL 90-448, and the Flood Disaster Protection 
Act, PL 93-234, authorize FEMA to administer programs for mapping flood hazards, providing 
flood insurance, and providing flood mitigation assistance. Implementing regulations for these 
programs are found in 44 CFR Parts 59-78.
Typical actions taken under these authorities are described below.

1.1.2 Response
In response to disasters, FEMA is authorized under the Stafford Act to provide state and local 
governments with the assistance that is essential to respond to immediate threats to life, public 
health and safety, and property. Response activities include emergency protective measures to 
save lives, protect public health and safety, and protect improved property. These actions may be 
undertaken directly by federal agencies or state and local agencies, with FEMA providing 
funding for extraordinary costs. 

1.1.3 Recovery
Under the Stafford Act, FEMA may provide funds to repair, restore, or replace disaster-damaged 
public facilities as well as facilities owned by certain private nonprofit organizations. Eligible 
facilities include:
* Roads and associated features, such as lighting, curbs, and sidewalks
* Bridges, culverts, and associated features, such as abutments, headwalls, and erosion protection
* Water control facilities, such as embankments, retention basins, and canals 
* Buildings and equipment
* Utilities, such as water and sewer lines and electrical distribution facilities
* Mass transit facilities
* Parks and recreational facilities

Often, the entity applying for assistance (referred to as the "subgrantee") wishes to take 
advantage of the opportunity presented by the necessary repair of a disaster-damaged facility to 
make improvements to, or change the design of, the facility. These actions are referred to as 
"improved projects." In other cases, the subgrantee determines that the public welfare would not 
be best served by restoring a damaged facility or the function of the facility. Funds originally 
available for the restoration of the damaged facility may be made available for the expansion or 
construction of other selected facilities, the purchase of capital equipment, or the funding of 
hazard mitigation measures. Such actions are referred to as "alternate projects."

1.1.4 Prevention and Mitigation
The Stafford Act, the National Flood Insurance Act, and the Flood Disaster Protection Act 
authorize FEMA to provide assistance with actions that reduce or eliminate threats to public 
health and safety and the risk of damage to public and private property during future disasters. 
FEMA may provide funds for mitigation measures applied to a specific facility, such as elevating 
a flood-prone building above flood elevation or reducing risks to the community at large through 
such measures as vegetation management to reduce the risk of wildfire. FEMA may also provide 
funds for the relocation or acquisition of facilities located in areas of hazard, such as floodplains, 
where repetitive damage is likely to occur. 

Under the National Flood Insurance Act and the Flood Disaster Protection Act, FEMA 
administers a nationwide program for the sale of flood insurance. Under this program, called the 
National Flood Insurance Program (NFIP), the federal government makes available affordable 
flood insurance to participating communities if those communities agree to adopt certain 
minimum standards for the management of floodplains. In support of the NFIP, FEMA publishes 
and maintains Flood Insurance Rate Maps (FIRMs), which depict flood hazards. Communities 
use these maps for floodplain management, and the lending and insurance industries use the 
maps for insurance purposes. FEMA revises these maps periodically as conditions affecting 
floodplains change. 

1.2 REGULATORY BACKGROUND
The National Environmental Policy Act of 1969 (NEPA) and the Council on Environmental 
Quality (CEQ) regulations implementing NEPA (40 CFR Parts 1500 through 1508) direct FEMA 
and other federal agencies to fully understand and take into consideration during decision 
making the environmental consequences of proposed federal actions (also referred to as 
projects). FEMA's regulations for NEPA compliance are described in 44 CFR Part 10. They 
specify that FEMA must comply with NEPA before making federal funds available for disaster 
response, recovery, and mitigation. Under these regulations, FEMA must use a systematic, 
interdisciplinary process that includes public involvement to evaluate the impacts of its actions 
on the environment. 

The Stafford Act and FEMA's implementing regulations for NEPA provide for the exemption of 
certain actions from NEPA and the exclusion of other actions from full review under NEPA (as 
described in Section 1.4). For all other actions, FEMA ensures compliance with NEPA through 
the preparation of Environmental Assessments (EAs). The EA is a concise public document that 
serves to provide evidence of the environmental impacts of a proposed action. The assessment 
includes alternatives to aid in decision making and concludes with one of two findings: a Finding 
of No Significant Impact (FONSI) or a Notice of Intent to prepare an Environmental Impact 
Statement (EIS). FEMA must prepare an EIS when significant environmental impacts are 
anticipated and cannot be mitigated.

1.3 THE PROGRAMMATIC ENVIRONMENTAL ASSESSMENT
FEMA has determined through experience that the majority of the typical recurring actions 
proposed for funding, and for which an EA is required, can be grouped by type of action or 
location. These groups of actions can be evaluated in a Programmatic Environmental Assessment 
(PEA) for compliance with NEPA and its implementing regulations without the need to develop 
and produce a time-consuming, stand-alone EA for every action.

This PEA evaluates typical recurring actions undertaken by FEMA within the State of California 
in preparation for, and in the wake of, disasters. The purpose of this document is to facilitate 
FEMA's compliance with NEPA by providing a framework to address the impacts of actions 
typically funded in response to flood, earthquake, fire, rain, and wind disasters and to prevent 
future disasters resulting from these types of events. 

This PEA also provides the public and decision-makers with the information required to 
understand and evaluate the potential environmental consequences of these actions. In addition 
to meeting the goals of impact identification and disclosure, this PEA addresses the need to 
streamline the NEPA review process in the interest of FEMA's primary mission of disaster 
response, recovery, and mitigation.

This PEA applies immediately to all actions described in Section 2 of this document that have 
been proposed for FEMA funding under all open declared flood, earthquake, fire, rain, and wind 
disasters in California. Open declared disasters are defined as disasters for which FEMA is still 
providing federal assistance under the Stafford Act. This PEA also applies, at FEMA's 
discretion, to subsequent disasters to be declared by the president. FEMA would notify the 
participating interested public and government parties and agencies of the applicability of this 
PEA to subsequent disasters.

The analysis in this PEA has relied on FEMA's historical experience with action typology, 
description, and consequences, as described in environmental documents from 1994 to 2002. The 
analysis in this PEA is also based on a review of scientific literature, consultation with regulatory 
agencies, and expert opinion. A FONSI will be prepared for the proposed actions described and 
assessed in this PEA. 

When FEMA has determined that an EA is required for a specific action, FEMA will use this 
PEA to determine if more site-specific information is available and what level of environmental 
analysis and documentation is required for the action to comply with NEPA. If the alternatives, 
levels of analysis, and site-specific information of an action proposed for FEMA funding are 
fully and accurately described in this PEA, FEMA would prepare a memorandum documenting 
this determination. This memorandum would state that FEMA has reviewed the proposed action, 
alternatives, potential impacts, and mitigation and found them to be fully and accurately 
described by this PEA and the PEA FONSI. Therefore, no further documentation would be 
required to comply with NEPA. The memorandum would also state that cumulative impacts (as 
described below) would not occur from the proposed action and alternatives. Because FEMA and 
the subgrantee would be required to implement the mitigation measures contained in the PEA, 
the memorandum would summarize the mitigation measures to be undertaken for the action and 
alternatives. A sample memorandum is provided as Appendix A.

If the specific action is expected to (1) create impacts not described in the PEA; (2) create 
impacts greater in magnitude, extent, or duration than those described in the PEA; or (3) require 
mitigation measures to keep impacts below significant levels that are not described in the PEA, 
then a Supplemental Environmental Assessment (SEA) and corresponding FONSI would be 
prepared to address the specific action. The SEA would be tiered from this PEA, in accordance 
with 40 CFR Part 1508.28.1 A sample SEA is presented in Appendix B.

If, during the preparation of the SEA, it is determined that a more detailed environmental review 
is required or that the specific action is really a poor fit for the typology described in the PEA, 
rather than trying to develop an SEA, it would be more effective to revert to the standard EA or 
EIS process, as required by NEPA and associated federal, state, tribal, and local statutes. 
Cumulative impacts are defined as environmental effects that are greater in magnitude, extent, or 
duration than the direct and indirect effects of the proposed FEMA-associated action when 
combined with the effects of other current and future actions, regardless of the proponent. For 
example, cumulative impacts could occur to wildlife habitat if a FEMA-funded action to create a 
fuel-break for a municipality were to occur in the same vicinity and time frame as a prescribed 
burn undertaken by the U.S. Forest Service (USFS). Individually, these vegetation management 
actions might allow sufficient habitat for displaced species, but the loss of habitat in both areas 
could substantially affect wildlife. Similarly, cumulative impacts could occur to hydrology in the 
case of a FEMA-funded action to widen and harden a waterway upstream from a site where a 
private entity plans to install a culvert. In this case, each separate action might have negligible 
effects on a bridge downstream, but the combination of the actions could cause the bridge to be 
overtopped. Cumulative impacts are not addressed in this PEA because analysis of these impacts 
requires specific knowledge of other actions occurring or proposed to occur within or near the 
study area. This information cannot be determined because the study area for this PEA is 
statewide, and the list of current and future actions that could cause cumulative impacts with 
FEMA-associated actions is infinite. Cumulative impacts will be considered when determining 
the compatibility of this PEA for specific actions. If cumulative impacts would be created, these 
impacts will be considered in an SEA. If no cumulative impacts would be created and the 
specific action is found to be fully and accurately described in this PEA and PEA FONSI, a 
prepared memorandum (discussed above) would state that cumulative impacts would not occur 
from the proposed actions.

A description of proposed actions and alternatives is provided in Section 2 (Description of 
Proposed Actions and Alternatives).

1.4 ACTIONS NOT COVERED BY THIS PROGRAMMATIC ENVIRONMENTAL ASSESSMENT
This PEA does not cover any action that meets the criteria for a statutory exclusion, described in 
44 CFR 10.8(c), or a categorical exclusion, described in 44 CFR 10.8(d). Also, the PEA does not 
cover any action that requires a stand-alone EA or EIS. Descriptions of such actions are 
explained below.

1.4.1 Statutory Exclusions
Section 316 of the Stafford Act exempts certain actions from review under NEPA. As listed in 
44 CFR 10.8(c), these statutory exclusions include:
* Debris removal
* Emergency protective measures or other assistance essential to saving lives, protecting public 
health and safety, and protecting property
* Repair, restoration, or replacement actions that do not substantially alter the location, footprint, 
function, or size of the original facility

Improved and alternate actions, described in Section 1.1.3, and mitigation actions, described in 
Section 1.1.4, do not qualify as statutory exclusions.
Even though an action may be statutorily excluded from NEPA, FEMA must still ensure that it 
complies with other applicable laws and regulations, such as the Endangered Species Act (ESA). 
However, if FEMA chooses to prepare an EA for this action, the PEA may be applicable.

1.4.2 Categorical Exclusions
The CEQ regulations provide for the categorical exclusion of actions that do not individually or 
cumulatively have a significant impact on the human environment. Neither an EA nor an EIS is 
required for these actions. FEMA's has identified 19 categorical exclusions, which are described 
in 44 CFR 10.8(d)(2). Examples of these categorical exclusions include the following:
* Acquisition of properties, and associated demolition or removal of structures, in situations 
where the resulting sites will remain as open space
* Planting of indigenous vegetation
* Physical relocation of individual structures where FEMA has no involvement in relocation site 
selection or development
* Restoration or retrofit of a facility in a manner that substantially conforms to the predisaster 
design, function, and location of the facility
* Improvements to existing facilities and construction of small-scale mitigation measures in 
previously developed or disturbed areas with substantially completed infrastructure when those 
actions do not alter basic functions, exceed the capacity of, or modify the intended land use of 
the existing facility

Certain actions that would otherwise be categorically excluded may be affected by extraordinary 
circumstances, as described in 44 CFR 10.8(d)(3), such as the presence of endangered species or 
the presence of archaeological or historical resources. In such cases, the categorical exclusion 
may not apply, resulting in the need to prepare an EA. The PEA may be applicable to such 
actions.

1.4.3 Actions Requiring an Environmental Assessment Instead of a Programmatic Environmental 
Assessment
The PEA does not apply to actions:
* That do not fall within one of the types of actions described in Section 2
* For which the analysis of impacts of alternatives presented in Section 4 is not applicable or 
comprehensive

In such cases, a separate, stand-alone EA must be prepared.

1.4.4 Actions Requiring an Environmental Impact Statement
If FEMA has previously determined that an EIS-level of review is required for an action, that 
action would not be considered in this PEA. If, in preparing an SEA or a separate EA, FEMA 
reaches the conclusion that the action has the potential to result in a significant environmental 
impact that cannot be mitigated such that a FONSI cannot be issued, FEMA must issue a Notice 
of Intent to Prepare an Environmental Impact Statement.

1.5 ACTIONS COVERED BY THE PROGRAMMATIC ENVIRONMENTAL ASSESSMENT
The PEA covers the following types of actions:
* Constructing, modifying, or relocating buildings and infrastructure (actions include 
construction of temporary facilities, restoration of disaster-damaged facilities, and mitigation 
actions)
* Modifying waterways, waterway crossings, and coastal features (category also includes 
temporary facilities, restored facilities, and mitigation measures)
* Vegetation management to reduce the risk of damage from flooding and from wildland fires
Specific types of actions are described in Section 2.

1.6 PURPOSE OF AND NEED FOR ACTION
FEMA's objectives are to:
* Reduce or eliminate immediate threats to life, public health and safety, and improved property 
resulting from major disasters or emergencies
* Repair, restore, or replace public facilities damaged in such events
* Reduce or eliminate the risk of future damage or loss associated with such events
Without FEMA action, the following would likely result:
* The threat of immediate harm or loss to individuals, families, communities, and properties 
would not be alleviated.
* Government agencies and private nonprofit organizations would not have the resources to 
restore essential public services or to restore, repair, or replace damaged facilities. 
* Communities would not have the resources to reduce the risk of repetitive damage from future 
events. Facilities would not be retrofitted to resist future damage; homes, businesses, and public 
buildings would not be relocated out of high-hazard areas; and threats from hazards such as 
flooding and wildfire would not be reduced through mitigation actions.

1.7 CALIFORNIA ENVIRONMENTAL QUALITY ACT AND APPLICABLE PERMITS
FEMA is responsible for ensuring that its actions comply with all applicable federal laws and 
regulations. However, in accepting assistance from FEMA, state and local governments as well 
as private nonprofit organizations must ensure that their actions also comply with applicable 
state and local laws. It is the subgrantee's responsibility to ensure that an action meets the 
requirements of the California Environmental Quality Act (CEQA) and to obtain additional 
permits as applicable. For example, for an action that includes work in a stream channel, the 
subgrantee is responsible for obtaining a streambed alteration permit from the California 
Department of Fish and Game (CDFG).

Under the CEQ regulations (40 CFR 1500.4), federal agencies must reduce excessive paperwork 
when complying with NEPA. Methods to attain this goal include incorporating material by 
reference, integrating NEPA requirements with other environmental review and consultation 
requirements, and eliminating duplication with state and local documents by preparing joint 
documents. Therefore, FEMA and subgrantees may cooperate to incorporate NEPA and CEQA 
documents by reference and prepare joint documents whenever practicable. In many cases, this 
cooperation consists of the subgrantee referencing the PEA in the CEQA document, as 
appropriate, and adding action-specific information and impact analysis. FEMA then completely 
references the CEQA document and all other relevant environmental studies in preparing the 
SEA. In some instances, the CEQA document and the SEA could be combined into a joint 
federal-state SEA.

1.8 USING THE PROGRAMMATIC ENVIRONMENTAL ASSESSMENT
1.8.1 Organization of the Programmatic Environmental Assessment
This PEA is organized into the following sections:
* Section 2 describes the actions that are covered by the PEA.
* Section 3 describes the affected environment that provides a basis for measuring the impacts of 
actions. 
* Section 4 describes the potential environmental consequences of implementing actions and also 
provides an Impact Summary Matrix, which allows for convenient comparison of actions.
* Section 5 describes the process of public participation and agency coordination in the 
preparation of this PEA and for its future use.
* Section 6 provides the list of references.

In addition to the main text, the PEA includes appendices that provide a sample PEA compliance 
memorandum, a sample SEA, responses from federal and state agencies, and programmatic 
agreements.

1.8.2 Use of the Programmatic Environmental Assessment
The PEA covers the actions and alternatives described in Section 2. As stated above, FEMA will 
prepare stand-alone EAs for proposed actions and alternatives that cannot be categorized among 
those described in that section. As stated in Section 1.3, a specific proposed action fully 
described and assessed in this PEA and the FONSI to this PEA would only require a 
memorandum regarding the proposed action to comply with NEPA (Appendix A). This PEA will 
also serve as a general document for SEAs and their corresponding FONSIs to tier from a 
specific action to comply with NEPA. Actions that have been determined, during the preparation 
of the SEA, to require a more detailed or broader environmental review will be subject to a 
standard stand-alone EA or an EIS, as required by NEPA. A sample SEA is provided in 
Appendix B.

1.8.3 Other Complementary Programmatic Documents
FEMA has executed and is in the process of preparing additional programmatic documents and 
interagency coordination that support the material contained in this PEA. The following provides 
a brief summary of these documents and their implementation.
* Memorandum of Understanding with the U.S. Fish and Wildlife Service (USFWS): As 
described in more detail in Section 3.4.1.1 of this PEA, Section 7 of the ESA requires FEMA to 
consult with the USFWS before implementing or funding any action that may affect threatened 
or endangered species under the jurisdiction of the USFWS. To consolidate and streamline the 
Section 7 consultation process, FEMA and the USFWS have executed a Memorandum of 
Understanding that establishes a framework for consultation between FEMA and the USFWS 
(Appendix C).
* Programmatic Consultation with the USFWS: FEMA is in the process of conducting 
Programmatic Consultation with the USFWS for future disasters throughout California. FEMA 
anticipates that the Programmatic Consultation it is now conducting with the USFWS will result 
in a Programmatic Biological Opinion (PBO) and a Programmatic Incidental Take Statement 
(PITS) for all future flood, earthquake, fire, rain, and wind disasters in California. Details of the 
Programmatic Consultation process with the USFWS are provided in Section 3.4.1.1.
* Programmatic Consultation with National Marine Fisheries Service (NOAA Fisheries): As 
described in more detail in Section 3.4.1.1 of this PEA, Section 7 of the ESA requires FEMA to 
consult with NOAA Fisheries before implementing or funding any action that may affect 
threatened or endangered species under the jurisdiction of NOAA Fisheries. FEMA has 
conducted this Programmatic Consultation through an informal consultation process with NOAA 
Fisheries for future disasters throughout California. FEMA submitted a Programmatic Biological 
Assessment to NOAA Fisheries on August 28, 2003 for all future flood, earthquake, fire, rain, 
and wind disasters in California. NOAA Fisheries replied to this submission by issuing a letter of 
concurrence on October 14, 2003. Details of the Programmatic Consultation process with NOAA 
Fisheries are provided in Section 3.4.1.1.
* Agreement regarding Section 7 consultation on the ESA when the U.S. Army Corps of 
Engineers (USACE) serves as lead agency: Under the Public Assistance Program, situations 
exist where the estimated cost of the work is less than the amount specified for the fiscal year 
under 44 CFR 206.203 and published in the Federal Register.2 The subgrantee is often 
responsible for preparing the application for FEMA grant funding. In some of these situations, a 
permit may be required or may have been applied for by the subgrantee under Section 404 of the 
Clean Water Act (CWA) and FEMA, due to the nature of the grant application process for these 
low-cost projects, is not able to review the action for its compliance or applicability to NEPA. In 
these situations, the USACE has agreed to be the federal agency responsible for complying with 
Section 7 of the ESA and the agency that conducts Section 7 consultation for such actions. A 
copy of this agreement is provided as Appendix D.
* Programmatic Agreement (PA) with the California State Historic Preservation Officer (SHPO): 
As described in more detail in Section 3.5.1.1 of this PEA, FEMA is required to comply with 
Section 106 of the National Historic Preservation Act (NHPA) before implementing or funding 
any action that may affect properties included in or eligible for inclusion in the National Register 
of Historic Places (NRHP). To streamline the Section 106 review process, FEMA, the SHPO, the 
California Office of Emergency Services (OES), and the Advisory Council on Historic 
Preservation (ACHP) have executed a disaster-specific PA for each recent disaster in California. 
In December 2003, these parties executed a PA for future disasters in California. Details of the 
PAs are provided in Section 3.5.1.1. 

2. Section 2 TWO - Description of Proposed Actions and Alternatives
This section describes typical actions, including the No Action Alternative, undertaken by 
FEMA in response to or in preparation for flood, fire, wind, rain, and earthquake disasters. Any 
action, including the No Action Alternative, has the potential to be the preferred alternative (that 
is, the proposed action) or an alternative to the proposed action for a specific project being 
funded by FEMA. The funding level for a specific action or alternative varies in accordance with 
the circumstances associated with that action or alternative, such as program requirements, 
location, and other circumstances and contingencies. Actions are described independently of the 
source or amount of funding. In addition, actions may be reviewed separately unless a physical 
or functional interdependency exists.

All actions considered in this PEA assume that FEMA action is:
* Required as a result of a major disaster declaration and is administered in accordance with the 
Stafford Act and its implementing regulations in 44 CFR Part 206, or
* Funded under FEMA's authorities for floodplain management in accordance with the National 
Flood Insurance Act and the Flood Disaster Protection Act and their implementing regulations in 
44 CFR Parts 59-78.

Several of the actions described in the following sections could be eligible for one of more 
categorical exclusions. As discussed in Section 1.4.2 of this PEA, actions that would normally be 
categorically excluded from NEPA review may have extraordinary circumstances that require an 
advanced analysis of impacts in the form of an EA. The evaluation of such actions in the PEA 
may be appropriate. Further, actions that may appear to be eligible for one or more categorical 
exclusions may involve improvements or other additional actions that would also require 
analysis in an EA. The PEA may also be applicable to these actions. Nonetheless, actions eligible 
for categorical exclusions (as described in 44 CFR 10.8[d][2]) should be categorically excluded; 
the listing of such actions below should not imply that a PEA is always necessary for these 
actions.

Some actions require federal, state, or local permits or coordination. It may be necessary for 
FEMA to coordinate with the following federal and state agencies when conducting 
environmental review:
* USACE
* State Water Resources Control Board (SWRCB)
* USFWS
* NOAA Fisheries
* CDFG
* State Lands Commission
* California Air Resources Board (CARB) and/or the applicable regional air quality jurisdictions

The agencies that FEMA or the subgrantee would need to coordinate with would vary depending 
on the particular action and the specific affected resources at the site where the action would 
occur. Some of the actions covered by this PEA and described below typically require 
coordination with certain agencies. In the description of the proposed actions and alternatives 
below, this typical coordination activity, when applicable, is discussed.

2.1 NO ACTION ALTERNATIVE
Inclusion of a No Action Alternative in the environmental analysis and documentation is 
required under NEPA and is defined as maintaining the status quo, with no FEMA funding for 
any alternative action. This alternative evaluates the effects of not providing eligible assistance 
for a specific action and provides a benchmark against which the alternative actions may be 
evaluated.

Although FEMA would not fund any action under this alternative, it is assumed for the purposes 
of this PEA that disaster-damaged facilities would be repaired or otherwise restored to pre-
disaster conditions with other public or private funds, including insurance payments. It is also 
assumed that no work would be undertaken on disaster-damaged facilities except for restoration 
to pre-disaster conditions. Damaged facilities would not be improved, and hazards would remain 
unmitigated at the disaster-damaged site. Further, no hazard mitigation measures would be 
undertaken to proactively reduce or prevent disaster damage from occurring in the future.

2.2 NONEMERGENCY DEBRIS REMOVAL 
Debris removal that is necessary to reduce or eliminate an immediate threat to life, public health 
and safety, or property is statutorily excluded from the NEPA process by the Stafford Act. 
However, nonemergency situations, such as in the restoration of facilities, occur where debris 
removal is necessary. The statutory exclusion does not apply in such situations. For purposes of 
this document, debris removal performed in these situations is referred to as "nonemergency 
debris removal."

Nonemergency debris removal under this alternative includes: 
* Removal of rock, silt, sediment, or woody debris that has been deposited by floodwaters in 
stream channels, bridge and culvert openings, canals, sedimentation basins, sewage treatment 
ponds, ditches, and other facilities in such a manner as to disrupt normal flows, navigation, 
recreation, or municipal services 
* Removal of woody debris from public areas or facilities after wind or fire events that damage 
or destroy trees
* Removal of rock and earth from public areas or facilities after landslides caused by 
earthquakes or heavy rains
* Removal of building rubble from public areas or facilities after earthquakes
Removal of material from stream channels usually requires a streambed alteration permit from 
the CDFG and coordination with the USACE for compliance and permitting under the CWA. All 
removed debris would be disposed of at approved and licensed disposal sites, in compliance with 
existing laws and regulations. Any hazardous materials or other contaminants would be removed 
and disposed of in an appropriate manner. Woody debris and construction materials can be 
recycled, if recycling facilities exist.

2.3 CONSTRUCTING, MODIFYING, OR RELOCATING FACILITIES
Under 44 CFR 206, FEMA is authorized to provide funds for constructing, modifying, or 
relocating facilities. Relevant action categories are as follows:
* Upgrading or otherwise modifying buildings
* Providing temporary facilities
* Acquiring and demolishing existing facilities 
* Repairing, realigning, or otherwise modifying roads, trails, utilities, and rail lines
* Constructing new facilities or relocating existing facilities
* Relocating the function of an existing facility
* Extending the pressurized water service area
* Developing demonstration projects
Actions involving facilities associated with watercourses or coastal features are described in 
Section 2.4.

2.3.1 Upgrading or Otherwise Modifying Buildings
Under this action, FEMA would provide funds to implement changes required by current 
building codes and standards or otherwise modify existing buildings. Often, these changes have 
the effect of making the structure more resistant to damage in future events. Typical activities 
include:
* Making buildings more fire resistant (e.g., by replacing roofs and doors with fire-resistant 
materials) or safer during fires (e.g., by installing sprinkler and alarm systems)
* Installing bracing, shear panels, shear walls, anchors, or other features so that buildings are 
better able to withstand earthquake shaking or high wind loads
* Modifying buildings to reduce the risk of damage during floods by elevating structures above 
the expected flood level or by floodproofing
* Modifying buildings to meet another need of a subgrantee, such as with an improved action or 
an alternate action

If a building is located in an identified floodplain and is substantially damaged, the NFIP 
requires that the building be elevated so that the lowest floor is at or above the base (100-year) 
flood elevation. Newly constructed buildings, such as those built to replace destroyed facilities 
must also meet this requirement, if located in floodplains. Structures can be elevated on extended 
foundation walls, piers, posts, columns, or compacted fill. All materials used below the base 
flood elevation must be flood resistant. Utilities, such as exterior compressors, must also be 
elevated above the base flood elevation.

A building can also be floodproofed so that floodwaters can encounter it without causing damage 
to the structure or its contents. "Dry floodproofing" methods involve the installation of flood 
shields, water-tight doors and windows, earthen barriers, and pumping systems to prevent water 
from entering the structure. "Wet floodproofing" involves the installation of vents and flood-
resistant materials so that water may enter and leave areas of the structure without causing 
damage. With both dry and wet floodproofing, utilities are modified, elevated, or relocated to 
prevent floodwaters from accumulating within them.

Buildings may also be upgraded to meet codes unrelated to damage from natural hazards, such as 
upgrades required by changes in capacity or function and upgrades necessary to meet the 
requirements of the Americans with Disabilities Act.

2.3.2 Providing Temporary Facilities
FEMA may provide temporary group housing sites when a disaster renders homes uninhabitable 
for long periods. Such sites are typically constructed using travel trailers or manufactured 
housing. Temporary housing that is located in a previously disturbed area and in an area of 
compatible residential use is categorically excluded from NEPA and, therefore, not covered in 
this PEA. However, temporary housing located on land not previously disturbed and/or not in a 
compatible residential area is evaluated in the PEA. Typical activities include:
* Developing the pads for dwellings
* Constructing ancillary facilities, such as roads, streets, and parking lots
* Installing utilities, such as potable water lines, sewer hookups, electricity (including proper 
street lighting), and telephones lines

This action would be implemented if other housing options, such as vacancies in hotel rooms or 
availability of rental units, are not feasible. Appropriate sites are not to be located in a floodplain, 
contain wetlands or critical habitat, affect historic properties or archaeological sites, or contain 
hazardous materials. Installation of housing units and utilities is accomplished in accordance 
with current codes and standards. After temporary housing is no longer needed at the disaster 
site, the temporary housing units and associated ancillary facilities are removed by FEMA and 
the land is restored to its original use. All removed materials would be stored for future use or 
disposed of in accordance with applicable laws and regulations.

FEMA may also provide funding for temporary relocation of essential public services, in the 
event that the structures housing those services are damaged, destroyed, or otherwise rendered 
inaccessible by a disaster. In most cases, the lease or purchase of facilities is eligible; however, 
construction of new facilities may be eligible if this action is cost-effective. Funds are also 
provided for the upgrades necessary to meet current codes and standards and the installation or 
modification of appurtenances necessary to operate facilities, such as utilities. 

2.3.3 Acquiring and Demolishing Existing Facilities
FEMA may provide funds for the acquisition and demolition of existing facilities if they are 
located in high-hazard areas and are subject to repetitive loss. Typically, these facilities are at a 
high risk because of (1) damage from flooding; (2) erosion of stream banks, beaches, slopes, or 
bluffs; (3) landslides; or (4) wildfire. These facilities may consist of private properties, such as 
houses and commercial buildings, or publicly owned facilities, such as utilities, roads, and 
bridges. A local government entity purchases private properties on a willing-seller basis, and 
once the property has been purchased, the property will be dedicated and maintained in 
perpetuity for uses compatible with open space, recreational, or wetlands management practices, 
pursuant to 44 CFR 206.434(d)

Existing facilities are either removed or demolished. All demolition materials are disposed of at 
approved and licensed disposal sites, in compliance with applicable laws and regulations. Any 
hazardous materials or other contaminants are removed and disposed of in an appropriate 
manner. Construction debris and household materials may be recycled, if recycling facilities 
exist. Once structures are removed, lots are graded to conform to the local topography and 
disturbed areas are revegetated with species approved for the local area. Frequently, the local 
government will develop the acquired land for recreational or open-space uses, such as parks, 
athletic fields, or walking and bike trails.

2.3.4 Repairing, Realigning, or Otherwise Modifying Roads, Trails, Utilities, and Rail Lines
Roads, trails, utilities, and rail lines are typically damaged when floods or heavy rains cause 
erosion, subsidence, or landslides. Earthquakes may cause similar damage. Repairs are 
accomplished by replacing earthen material lost during the disaster and replacing the damaged 
surface, utility line, or, in the case of rail lines, ballast and track. It may be necessary to stabilize 
the replacement fill using rock, grout, timber walls, or steel sheet piling. Hazard mitigation 
measures may be installed to prevent future damage. For example, a pipe may be installed to 
convey drainage beneath a road, thus preventing future washouts, or a utility line may be encased 
in concrete in an area vulnerable to erosion.

If the area of damage is unstable, does not allow for repair, or is subject to repetitive loss, a 
facility may be realigned so that the area of damage is avoided. Property acquisition or a change 
in easement may be necessary.

Facilities may also be modified as part of improved actions or alternate actions to meet 
additional needs of the subgrantee.

2.3.5 Constructing New Facilities or Relocating Existing Facilities
If a facility is located in a floodplain or other hazard area, is subject to repetitive damage, or has 
been damaged in such a way that restoration in the current location is not practical or cost-
effective, FEMA may fund the construction of a new facility or the physical relocation of the 
existing facility. Examples of this action include construction of buildings, roads, trails, utilities 
and utility lines, and rail lines in a different area from the existing facility. The physical 
relocation of existing facilities is only practical with buildings. In cases of both new facility 
construction and physical relocation, FEMA may fund the cost of land acquisition and the 
construction of appurtenant features, such as access roads and utilities. For properties in the 
hazard area, FEMA would acquire damaged properties, demolish existing structures (except in 
cases of physical relocation), and place deed restrictions that would limit future uses to open 
space in perpetuity.

New facilities (including buildings, roads, trails, utilities and utility lines, and rail lines) could 
also be constructed as improved actions or alternate actions to meet additional needs of the 
subgrantee.

2.3.6 Relocating the Function of an Existing Facility
Under this action, FEMA would fund the relocation of the function of a facility to an existing 
facility that has adequate capacity to handle the additional load with minor modifications, if any. 
For structures, the occupants and materials would be relocated to alternative structures, traffic 
would use alternate routes, and utility services would be provided by alternative methods. This 
action would not entail any major physical construction or addition to the existing facility and, if 
any work would be required, it would consist of only minor modifications. A typical example is 
transferring students from a damaged or floodprone school to a suitable existing school nearby, if 
feasible in terms of capacity and convenience for students, families, and teachers. For properties 
in the hazard area, FEMA would acquire damaged properties, demolish existing structures, and 
place deed restrictions that would limit future uses to open space in perpetuity.

2.3.7 Extending the Pressurized Water Service Area
As a means of preventing future damage during wildfires, FEMA may fund the extension of 
pressurized pipelines to a developed area that is prone to repetitive fire damage. Under this 
action, an existing, pressurized system is extended so that fire hydrants can be installed in the 
area where damage is likely to occur. Installation, which involves excavation, is typically 
completed within the road right-of-way.

2.3.8 Developing Demonstration Projects
Demonstration projects focus on public education and are designed to highlight procedures that 
can be employed by the public to reduce property damage during flood, fire, wind, and 
earthquake disasters. Potential demonstration projects would involve the development of a model 
facility to demonstrate how hazard mitigation technologies can be used to reduce the potential 
damage during a disaster. Flood demonstration projects would involve items such as elevating a 
structure or waterproofing windows and doors that are below the elevation of the 100-year flood 
event. A fire demonstration project would include vegetation management around a facility and 
replacing roofs, doors, and windows with fire-resistant materials. Wind and earthquake 
demonstration projects would include changes to the structural design of buildings to allow them 
to withstand higher wind velocity or more movement during an earthquake.

2.4 ACTIONS INVOLVING WATERCOURSES AND COASTAL FEATURES
Many actions pertain to inland water sources, such as streams, rivers, canyons, and lakes, and 
coastal features, such as harbors and beaches. Inland water sources may be perennial or may be 
dry during the summer months. During construction, Best Management Practices (BMPs) are 
normally employed to reduce soil erosion and prevent or reduce the amount of sediment entering 
the water source. Work in a stream channel may involve temporary diversion of the channel 
using sandbags or a cofferdam constructed of fill. Heavy equipment is typically operated from an 
adjacent road, bank, or other feature; however, in some cases, it may be necessary to operate 
equipment in a channel area once flow has been diverted. A pipe or a temporary secondary 
channel may be used to convey the diverted water. 

The PEA does not apply to flood control works in undeveloped areas or that directly or indirectly 
serve to protect undeveloped areas. Such an action would require preparation of an EA or an EIS.
If an action impacts a natural waterway, alters vegetation adjacent to a stream corridor, or 
impacts a floodplain, coordination with the USACE, CDFG, and SWRCB may be required. If the 
action affects a water source that supports anadromous fish species, such as salmon, coordination 
with the NOAA Fisheries is required. If the action involves channel modifications, changes to 
the capacity of bridges and culverts, or the installation of attenuation structures, it may be 
necessary to conduct hydraulic/hydrologic analyses to evaluate the potential effect of changes of 
downstream flow rates.

Relevant categories of actions are as follows:
* Repairing, stabilizing, or armoring embankments
* Creating, widening, clearing, or dredging a waterway
* Constructing or modifying a water crossing
* Constructing or modifying a water detention, retention, or storage facility
* Constructing or modifying other flood control structures
* Constructing or modifying a coastal feature

2.4.1 Repairing, Stabilizing, or Armoring Embankments
These actions would involve the repair of earthen or rock embankments damaged by 
floodwaters. Examples include natural stream banks (such as those in parks); road, trail, and rail 
line embankments; embankments for irrigation and navigation canals; and levees used for flood 
control and reclamation. In addition to repair of damaged features, FEMA may fund measures 
designed to prevent damage in future flood events.

In addition to replacing fill material, embankments may be stabilized or armored through:
* Placing of rock riprap
* Hardening with concrete or soil cement
* Installing retaining walls, gabions, or geotextile fabrics
* Using bioengineering techniques, such as planting vegetation, placing root wads, or placing 
willow bundles 
A combination of these techniques may be employed. For example, rock and geotextiles, when 
used with root wads and willow bundles, may provide mitigation from erosion while enhancing 
the natural values of a stream corridor.

2.4.2 Creating, Widening, Clearing, or Dredging a Waterway
These actions would be employed to reduce the flood hazard to adjacent lands, facilities, or 
populated areas.

New channels would be constructed to convey excess flows around flood-prone areas during 
flood events. Drainage swales, earthen channels, concrete channels, or subsurface concrete pipes 
can be used as a means of conveyance. The new channel would be constructed in a dry 
environment and connected to the stream after the channel has been completed. The channel may 
have an inlet weir higher than the elevation of the normal flow so that normal flows would 
remain in the natural channel. The outlet may be armored with concrete or rock riprap to prevent 
excessive erosion of the existing channel.

Existing channels would be widened to allow a channel to convey a larger volume of water. 
Conveyance may also be increased by replacing earthen banks or channel bottoms with concrete. 
To the extent possible, the construction would be conducted from the top of the bank, but many 
actions would require construction equipment to work in the stream channel. In perennially 
flowing streams, work in a stream channel would generally be restricted to the low-flow period, 
and the flow would be diverted around the construction area. A pipe or a temporary secondary 
channel would be used to convey the diverted water.

As an alternative to constructing a bypass or modifying an existing channel, the existing channel 
may be cleared of vegetation or sediment to increase conveyance. This action is often used in 
developed areas where modifications are not feasible as well as in areas where years of 
inadequate maintenance have allowed trees and brush to grow within the channel or sediment 
and debris to accumulate in the channel or around culverts and bridges. Vegetation may be 
removed through mechanical means, by hand, or by application of herbicides (see Section 2.5). 
Vegetation may be removed not only from the channel but also from the banks and high-water 
areas, thus reducing the risk that floating debris will be trapped by trees or heavy brush. 
Sediment and debris may be removed by dredging, through use of heavy equipment, or by hand, 
as described in Section 2.2. All removed debris would be disposed of at approved and licensed 
disposal sites, in compliance with applicable laws and regulations. Woody debris and vegetation 
can be recycled, if recycling facilities exist.

2.4.3 Constructing or Modifying a Water Crossing
FEMA may fund the repair or replacement of damaged water crossings, the enlargement of 
openings to allow greater conveyance and to reduce the risk that debris will get trapped during 
floods, or the installation of bank protection or other means to reduce the risk of erosion. 
Crossings may also be relocated or improved to avoid high-hazard areas, repetitive damage, or 
areas where reconstruction is not cost-effective or feasible. 
Culverts may consist of corrugated metal pipes, reinforced concrete pipes, or reinforced concrete 
box culverts. The capacity of a culvert crossing may be increased to reduce the risk of flooding 
to the surrounding area, or the culvert may be modified to prevent overtopping or erosion of the 
crossing. Typical measures include:
* Increasing the size of a culvert or adding additional culvert barrels
* Changing the type of culvert
* Changing the location or alignment of the culvert
* Adding features, such as a headwall, discharge apron, or riprap, to reduce the risk of erosion or 
damage to the culvert or the crossing
If a culvert's capacity is increased substantially, the reduced attenuation of flow could cause 
increased flooding or erosion downstream. These effects would be evaluated by conducting 
hydraulic and hydrologic analyses.
Similarly, bridges may be modified to increase capacity to reduce the risk of flooding or to 
reduce the risk of damage to the crossing. Typical actions include:
* Widening of existing openings or construction of new openings
* Reconfiguring bracing to reduce the risk that debris will be trapped
* Installing protective features, such as concrete abutments or riprap, to reduce the risk of 
damage due to erosion and scour
* Replacing a multispan structure with a clear-span structure

A bridge may be installed to replace a culvert as a means of increasing the flow capacity of a 
crossing.

If the piers of the bridge are located within the channel of the watercourse, it may be necessary to 
construct a temporary diversion, as described above. As with culverts, modifications to bridges 
may attenuate flow and require an analysis of downstream effects on erosion and flooding.
Low-water crossings may be installed or improved as an alternative to repairing or replacing a 
culvert or bridge. Constructing or upgrading a low-water crossing would typically involve 
hardening the banks and bottom of a water body. A temporary diversion may be necessary 
during construction activities. As for bridges and culverts, flow attenuation and downstream 
impacts to erosion and flooding would require evaluation.

2.4.4 Constructing or Modifying a Water Detention, Retention, or Storage Facility
Potential actions include the construction, enlargement, or restoration of detention basins, 
retention basins, sediment ponds, and reservoirs to reduce flood flows or to provide a water 
source for fighting fires in an area of high fire hazard. The creation and/or enlargement of water 
storage reservoirs would be most frequently associated with flood disasters, and to a lesser extent 
fire disasters.

Detention dams, retention dams, and sediment ponds would be routinely constructed to 
temporarily store flood flows so that downstream peak flows would be reduced. The stored water 
would be released at a slower rate so that the existing drainageways can convey the water 
without contributing to downstream flooding. All areas disturbed during the construction of the 
detention dams, retention dams, or sediment ponds would be revegetated with native plant 
species. This action would also include the repair or restoration of water retention structures. All 
sediment removed from detention dams, retention dams, and sediment ponds would be disposed 
of in a manner consistent with federal, state, and local laws and regulations.

Frequently in rural areas, fire fighting is heavily constrained by the lack of water that can be used 
by firefighters. In response to this need, proposed actions may also include the creation of 
retention dams in locations that can readily be accessed by firefighters either as a direct source of 
water or as a source of water to fill their water supply trucks. All areas disturbed during the 
construction of the retention dam would be revegetated with native fire-resistant plant species.

2.4.5 Constructing or Modifying Other Flood Control Structures
A flood control structure is a facility designed to prevent floodwaters from entering a flood-
prone area. Typical examples include levees (also referred to as dikes) and floodwalls. Actions 
include:
* Repairing damaged facilities, usually during emergency situations 
* Installing embankment protection, as described in Section 2.4.1
* Raising the height of existing facilities to prevent overtopping in future floods
* Constructing new facilities to protect flood-prone areas from damage during future floods
* Modifying or installing interior drainage systems to reduce the risk of damage behind levees 
and floodwalls during heavy rains or flooding events on tributary streams
Levees would be repaired or constructed using compacted fill and, in some cases, riprap 
protection at the base. Bare earth would be seeded with grasses to prevent erosion. Typically, a 
road would be installed on the crest with gravel to allow for maintenance. Floodwalls, typically 
built in urban areas, would be constructed using reinforced concrete or grouted, reinforced 
concrete block. Excavation would be necessary to install footings. Both types of structures would 
include interior drainage systems that may include pumps for removing accumulated water.

2.4.6 Constructing or Modifying a Coastal Feature
These actions would involve the repair, replacement, or construction of facilities in coastal 
environments, such as estuaries, inlets, harbors, and beaches. These facilities include:
* Recreational facilities, such as piers and boat ramps
* Facilities for maritime use, such as docks and slips
* Shoreline protection devices, such as seawalls, groins, jetties, and revetments
* Coastal flood control structures, such as levees
Construction activities would be expected to occur in water and would involve driving piles, 
placing rock or soil, or dredging sand, mud, or other sediment. 

2.5 VEGETATION MANAGEMENT
Vegetation management would be employed to reduce the risk of wildfire and, as described in 
Section 2.4, to increase the ability of channels to convey flows, thus reducing the risk of flood 
damage. These actions may be accomplished using mechanical means, hand clearing, application 
of herbicides, prescribed burning, or grazing. Some actions may include a combination of these 
methods.

Vegetation management actions in areas where threatened and endangered species are thought to 
exist would require coordination with the USFWS or NOAA Fisheries. Prescribed burns require 
coordination with the CARB and/or the applicable regional air quality jurisdictions.
Relevant categories of actions are as follows:
* Mechanical or hand clearing of vegetation
* Herbicidal treatments
* Prescribed burns
* Biological control

2.5.1 Mechanical or Hand Clearing of Vegetation
This action would involve construction, expansion, and/or maintenance of fuel breaks and fuel-
reduction zones. For the purpose of this document, fuel breaks are corridors where all woody 
vegetation has been removed. The purpose of a fuel break would be to reduce the extent of fire 
and to provide a location in which firefighters can work safely and effectively. Fuel breaks can 
also be compacted or graded for use as fire access roads.

Unlike fuel breaks, fuel-reduction zones (also called shaded fuel breaks) would involve the 
selective removal of vegetation such that a certain proportion of vegetation is left in place. Fuel-
reduction zones differ from untreated-forested areas because in fuel-reduction zones low- and 
mid-height vegetation has been removed or reduced and the density of mature trees has been 
reduced. The purpose of fuel-reduction zones is to reduce the speed at which a fire spreads and to 
create a safer environment for firefighters. To create fuel-reduction zones, dead and diseased 
trees would be removed, along with high-ignition-potential species, such as eucalyptus or 
Monterey pine. Low- and mid-height individual plants and limbs would be removed or reduced 
to minimize fire ladders (vegetation that permits fire to travel from the understory to the canopy).
Mechanical removal would use heavy equipment that can uproot, crush, pulverize, or cut the 
trees and brush being removed. Hand removal would involve the use of chainsaws, axes, and 
hoes to cut and uproot vegetation. Vegetation downed as a result of mechanical or hand removal 
would be piled and burned on site, chipped and spread on site, or loaded and hauled from the 
site. After the removal of the targeted vegetation, cleared areas may be revegetated with native 
fire-resistant species. The subgrantee would be responsible for the maintenance of created fuel 
breaks and fuel-reduction zones.

On occasion, mechanical and/or hand removal of vegetation would be employed around a much 
larger area that has been targeted for a prescribed burn, as discussed in Section 2.5.3, to reduce 
the potential that the set fire will escape from the burn area.

2.5.2 Herbicidal Treatments
Actions generally associated with herbicidal treatment include the removal of targeted exotic 
invasive species within specific areas and the prevention of growth and resprouting (e.g., 
eucalyptus removal) of undesirable vegetation once an area has been cleared of excessive 
vegetation by mechanical removal, hand removal, and/or prescribed burns. Only readily accepted 
and registered chemicals would be used to control the growth of undesired vegetation. After 
treatment, some areas may be revegetated with locally occurring, native vegetation that is fire 
resistant.

2.5.3 Prescribed Burns
Prescribed burns would be used in areas with high-fire-hazard potential due to the amount of fuel 
that is on the forest floor. The intent of a prescribed burn is similar to that of the fuel-reduction 
zones discussed in Section 2.5.1 except that the treatment area is typically larger. Prescribed 
burns would only be proposed and authorized in areas where it can be ensured that the fire can be 
controlled and contained within the proposed burn area. As discussed in Section 2.5.1, prescribed 
burn projects would be frequently combined with mechanical and/or hand removal of vegetation 
around the perimeter of the proposed burn area, which would help to ensure that the fire is 
contained. Generally, prescribed burns would be designed to minimize impacts on riparian 
vegetation adjacent to a perennial stream.

Prescribed burns would require interagency coordination by the subgrantee to ensure that all 
appropriate federal, state, and local agencies have been notified of the action and that all their 
concerns have been addressed. FEMA requires that the applicant follow the burn procedures 
outlined in the California Environmental Protection Agency's Forest Management Burning 
Handbook (CEPA 1994). The burn must be terminated if weather conditions become 
undesirable.

Burn actions can also include the burning of trees and brush that have been piled as the result of 
mechanical and/or hand removal activities. The burning of these piles would require a burn plan 
and interagency coordination prior to implementation.

2.5.4 Biological Control
Under this action, the subgrantee would allow cattle, horses, goats, sheep, or other livestock to 
graze on grasses and other vegetation as a means of control. The subgrantee would fence the area 
proposed for grazing, so that the animals would not graze outside of the proposed area. The type 
of animals, timing, duration, and stocking rate would be selected based on the targets of the 
vegetation management plan (i.e., the quantity and quality of residue to remain).

2.6 PUBLICATION AND REVISION OF FLOOD INSURANCE RATE MAPS
As described in Section 1, FEMA manages the NFIP. The program is based on an agreement 
between local communities and the federal government that if a community implements 
programs to reduce future flood risks, the federal government makes flood insurance available 
within the community as a financial protection against flood losses that occur. In support of the 
NFIP, FEMA has undertaken a nationwide effort to identify and map flood hazards. These flood 
hazards are shown on Flood Insurance Rate Maps (FIRMs), which FEMA produces for each 
community participating in the program. The FIRMs show identified Special Flood Hazard 
Areas (SFHAs), which are areas subject to inundation during a flood having a 1 percent chance 
of occurrence in a given year (also known as the base flood or 100-year flood).
FEMA periodically revises FIRMs to reflect changes in hydrologic and hydraulic conditions, to 
update map information based on more detailed data, or to reflect changes to the built 
environment, such as the placement of fill in the floodplain or the construction of a flood control 
channel. These revisions may result in changes to the base flood elevations and floodplain 
delineations shown on the FIRMs. Communities are required to update their floodplain 
management ordinances to reflect the revised maps. 

Development may take place within the SFHA, provided that the development is in compliance 
with local floodplain ordinances, which must meet the minimum federal requirements (see 
Section 2.3.1). Local governments are responsible for implementing these floodplain 
management ordinances. If the community fails to adopt or enforce its floodplain management 
ordinance, FEMA may sanction the community or suspend it from the NFIP, thereby restricting 
the financial benefits of participating in the program. However, FEMA has no other authority or 
responsibility to govern whether and how this development occurs. FEMA's involvement in 
floodplain management is otherwise limited to publication and revision of the FIRMs, which are 
categorically excluded from the preparation of an EA or an EIS (44 CFR 10.8[d][2][iii]). 
Therefore, impacts resulting from the publication and revision of FIRMs are not evaluated 
further in this PEA.

3. Section 3 THREE - Affected Environment
The following subsections discuss the setting and affected environment of 12 resource areas in 
California:
* Geology, Seismicity, and Soils
* Air Quality
* Water Resources
* Biological Resources
* Cultural Resources
* Socioeconomics and Public Safety
* Land Use and Planning
* Public Services and Recreation
* Transportation
* Noise
* Hazardous Materials and Wastes
* Visual Resources
This discussion is broad and regional in nature. It does not include a complete inventory of each 
resource but does provide information to characterize those resources.

3.1 GEOLOGY, SEISMICITY, AND SOILS
Key resource categories and assessment variables described in this section include geology and 
physical processes, geologic resources, geologic hazards, geomorphology, seismicity and seismic 
hazards, and soils.

3.1.1 Regulatory Background

3.1.1.1 Federal Laws and Regulations
Executive Order 12699: Seismic Safety of Federal and Federally Assisted or Regulated New 
Building Construction 

The purposes of these requirements are to: 
* Reduce risks to the lives of occupants of buildings owned by the federal government, leased 
for federal uses, or purchased or constructed with federal assistance and to persons who would be 
affected by the failures of federal buildings in earthquakes
* Improve the capability of essential federal buildings to function during or after an earthquake
* Reduce earthquake-related losses to public buildings in a cost-effective manner
A building means any structure, fully or partially enclosed, used or intended for sheltering 
persons or property. 

Under this order each federal agency responsible for the design and construction of a federal or 
federally funded building must ensure that the building is designed and constructed in accord 
with appropriate seismic design and construction standards. These standards are promulgated 
through the National Earthquake Hazard Reduction Program (NEHRP) and are subsequently 
incorporated into the model building codes that are used as the basis for local building codes in 
most municipalities. NEHRP periodically publishes new standards; the latest NEHRP standards 
were published in 2000. This requirement pertains to all building projects for which detailed 
plans and specifications were initiated subsequent to the issuance of the order. 
Each federal agency responsible for the construction and lease of a new building must also 
ensure that the building is designed and constructed in accord with appropriate seismic design 
and construction standards. Local building codes are used in design and construction and 
augmented when necessary to achieve appropriate seismic design and construction standards. 
According to Office of Management and Budget Circular A-119 of January 17, 1980, entitled 
Federal Participation in the Development and Use of Voluntary Standards, nationally recognized 
private-sector standards and practices are to be used unless the responsible agency finds that 
none are available that meet its requirements. This circular states that design criteria should 
consider the seismic hazards in various areas of the country, as shown in the most recent edition 
of the American National Standards Institute Standards A58, Minimum Design Loads for 
Buildings and Other Structures, or subsequent maps adopted for federal use. Local building 
codes may be used if determined by the responsible agency or by the Interagency Committee for 
Seismic Safety in Construction to provide adequately for seismic safety. Special seismic 
standards and practices may be used if required by a unique agency mission.

Farmland Protection Policy Act of 1981
The Farmland Protection Policy Act (7 United States Code [USC] 4201 et seq.) and the U.S. 
Department of Agriculture's implementing procedures require federal agencies to evaluate the 
effects (direct and indirect) of their activities before taking any action that could result in 
converting designated prime or unique farmland for nonagricultural purposes. If an action would 
adversely affect farmland preservation, alternative actions that could avoid or lessen adverse 
effects must be considered. Federal agencies also must ensure that their programs, to the extent 
practicable, are compatible with state, local, and private programs to protect farmlands. 
Determination of the level of impact to prime and unique farmland or farmland of statewide and 
local importance is done by the lead federal agency, which inventories farmlands affected by the 
proposed action and scores part of an AD 1006 Form, Farmland Conversion Impact Rating, for 
each alternative. Through consultation with the Natural Resources Conservation Service (NRCS) 
staff in the particular county of the proposed action, NRCS completes the AD 1006 Form and 
determines the level of consideration for protection of farmlands that needs to occur under the 
Act. 

3.1.1.2 State and Local Laws and Regulations
1998 California Building Code
The CBC contains the minimum standards for design and construction in California. Local 
standards other than the CBC may be adopted if those standards are stricter. The CBC 
incorporates the standards associated with seismic engineering that are detailed in the Uniform 
Building Code (UBC) of 1997. 

The 1997 UBC and therefore the 1998 CBC reflect the National Earthquake Loss Reduction 
Program provisions published in 1994. With the publication of the 2000 NEHRP standards, the 
1998 CBC no longer reflects current standards. Consequently, until California adopts a building 
code reflecting the 2000 NEHRP standards, structures permitted after the 2000 standards became 
available will not be in compliance with Executive Order (EO) 12699.

California Public Resources Code § 25523(a), 20 California Code of Regulations § 1752(b) and 
(c), and the 1972 Alquist-Priolo Earthquake Fault Zoning Act (Amended 1994)
The Alquist-Priolo Earthquake Fault Zoning Act (A-P Act) was passed in 1972 to mitigate the 
hazard of surface faulting to structures for human occupancy. This state law was a direct result of 
the 1971 San Fernando Earthquake, which was associated with extensive surface fault ruptures 
that damaged numerous homes, commercial buildings, and other structures. Surface rupture is 
the most easily avoided seismic hazard. 

The main purpose of the A-P Act is to prevent the construction of buildings used for human 
occupancy on the surface trace of active faults. The act only addresses the hazard of surface fault 
rupture and is not directed toward other earthquake hazards. The Seismic Hazards Mapping Act, 
passed in 1990, addresses nonsurface fault rupture earthquake hazards, including liquefaction 
and seismically induced landslides. 

The A-P Act requires the State Geologist to establish regulatory zones (known as Earthquake 
Fault Zones) around the surface traces of active faults and to issue appropriate maps. The maps 
are distributed to all affected cities, counties, and state agencies for their use in planning and 
controlling new or renewed construction. Local agencies must regulate most development 
projects within the zones, including all land divisions and most structures for human occupancy. 
Single-family wood-frame and steel-frame dwellings of up to two stories that are not part of a 
development of four units or more are exempt. However, local agencies can be more restrictive 
than state law requires. 

Before a proposed action can be permitted, cities and counties must require a geologic 
investigation to demonstrate that proposed buildings will not be constructed across active faults. 
An evaluation and written report of a specific site must be prepared by a licensed geologist. If an 
active fault is found, a structure for human occupancy cannot be placed over the trace of the fault 
and must be set back from the fault (generally 50 feet). 

Earthquake Fault Zones are regulatory zones around active faults. The zones are defined by 
turning points connected by straight lines. Most of the turning points are identified by roads, 
drainages, and other features on the ground. Earthquake Fault Zones are plotted on topographic 
maps at a scale of 1 inch equals 2,000 feet. The zones vary in width, but average about 1/4 mile 
wide. 

Effective June 1, 1998, the Natural Hazards Disclosure Act requires that sellers of real property 
and their agents provide prospective buyers with a "Natural Hazard Disclosure Statement" when 
the property being sold lies within one or more state-mapped hazard areas, including Earthquake 
Fault Zones.

California Public Resources Code Chapter 7.8 and the Seismic Hazards Mapping Act of 1990
This law addresses shaking, landsliding, and liquefaction hazards. It expands from the surface 
fault-rupture hazard addressed in the A-P Act to other seismic hazards, including shaking, 
landsliding, and liquefaction. This law requires the State Geologist to prepare seismic hazard 
maps that cities and counties must use in preparing their general plan safety elements and in 
regulating new development to avoid or mitigate these seismic hazards. The California 
Geological Survey (formerly the California Division of Mines and Geology) has adopted 
regulations for the mapping process under Title 14 of the California Code of Regulations (CCR).
The Seismic Hazards Mapping Act of 1990 allows the lead agency to withhold permits until 
geologic investigations are conducted and mitigation measures are incorporated into plans. This 
act not only addresses seismically induced hazards, but also includes such things as expansive 
soils, settlement, and slope stability. Cities and counties may adopt more stringent criteria and 
policies, as they see fit.

Field Act
After the 1933 Long Beach earthquake, statewide seismic design and construction requirements 
were mandated for public schools. Commonly known as the Field Act, these state requirements 
were extended to the evaluation and retrofitting of existing pre-Field Act buildings with the 
passage of the Garrison Act (1939) and the Greene Act (1967). The scope of the regulations is 
found in CBC, Part I, Title 24, Sec. 4-301 et seq.

Field Act buildings have stringent construction quality control procedures (required by CCR 
Title 24 Part 1). The requirements in this act have been reconsidered on several occasions and 
recommendations have been made for altering them to be more effective. For example, the 
California Earthquake Hazards Reduction Program in Initiative 1.3 in 1991 laid out a goal for all 
school districts to identify and reduce unacceptable earthquake hazards in public schools by the 
year 2000. The Northridge earthquake provided many observations of school damage that was 
not covered by the act. Privately owned schools are excluded from the Field Act requirements. 
Also, the requirements relating to hazard reduction of existing pre-act schools does not apply to 
the California State University or University of California systems, but it does apply to 
community colleges.

3.1.1.3 Local Laws and Regulations
Counties and cities have developed general plans that include county- or city-specific 
descriptions of existing geology and geologic resources.

Shortly after the 1971 San Fernando earthquake, the state legislature passed a requirement that 
all city and county general plans include a seismic safety element. During the mid-1970s local 
governments prepared and adopted seismic safety elements to meet statutory deadlines. In l984, 
the state legislature streamlined general plan requirements, combining the overlapping safety and 
seismic safety elements into a single safety element.

Each planning agency has to prepare, and the legislative body of each county and city has to 
subsequently adopt, a comprehensive, long-term general plan for the physical development of the 
county or city, and of any land outside its boundaries that in the planning agency's judgment 
bears relation to its planning. 

3.1.2 Geology, Geologic Hazards, and Soils in California
3.1.2.1 Geomorphic Provinces
A brief examination of the rock types, geologic structure, and geomorphology (landscape 
features) of California shows some distinct regional differences. The term "geomorphic 
province" is generally defined to be any area that displays a distinctive geologic and landscape 
character as defined by the amount of relief, types of landforms, orientation of valleys and 
mountain ridges, and types of vegetation. As the underlying geology is one of the controlling 
factors that define the geomorphic character of each province, the geology of California is 
commonly described in terms of its geomorphic provinces. California comprises 12 geomorphic 
provinces (Figure 3.1-1). These provinces are described from north to south in the following 
sections.

Klamath Mountains Province
The Klamath Mountains Province is located in the northwestern corner of California and 
southwestern corner of Oregon between the northern Coast Ranges and Cascade Range Province. 
It is made up of several mountain ranges including the Trinity Alps, the Marble Mountains, the 
Salmon Mountains, and the Siskiyou Mountains. It is a north-trending area that covers 
approximately 11,800 square miles. This province consists of a rugged topography with peaks 
and ridges of similar elevations, between 4,900 to 6,900 feet above sea level. 

No zoned active faults according to the A-P Act exist within this province (Hart 1994). However, 
many Quaternary and pre-Quaternary low-angle thrust faults occur, such as the South Fork 
Mountain thrust to the west of the province, which separates the province from the younger rocks 
of the Coast Ranges. None of these faults are considered active or potential earthquake sources. 
One substantial earthquake source exists in this region. Beneath the Klamath Mountains, the 
Gorda plate (a fragment of the Pacific plate) is being subducted1 eastward beneath the North 
American plate (Ludwin, Weaver, and Crosson 1991; Urhammer 1991). Friction between the 
overriding North American plate and the Pacific plate has the potential to generate "megathrust" 
earthquakes, as does deformation within the downgoing plate itself (Heaton and Hartzell 1987).

Cascade Range Province
The Cascade Range comprises a 500-mile-long chain of volcanoes that extend from northern 
California into Oregon and Washington. The Cascade Range province in California is the 
southern tip of the chain and the geology is more similar to that of the Pacific Northwest than to 
the geology of California. Within California, the province is located between the Klamath 
Mountains to the west and the Modoc Plateau Province to the east and north of the Great Valley 
and Sierra Nevada Provinces. One of the most prominent volcanoes of the Cascade Range in 
California is Mount Shasta, which rises 14,162 feet above sea level. The southernmost peak of 
the Cascade Range and the second highest peak within the province is Mt. Lassen (10,453 feet), 
which last erupted sporadically between 1914 and 1921 (Miller 1989). The portion of the 
Cascade Ranges within California resulted from the subduction of the Gorda Plate. As the 
subducted plate is pushed into the mantle it heats up and the rocks eventually melt, producing 
magma. The molten magma is buoyant and rises through the overlying mantle and crust until it is 
erupted as lava. Successive lava eruptions eventually build up into volcanoes. Mount Shasta has 
been built up over the last 10,000 years, when at least 13 major eruptions have occurred. During 
the last 4,500 years, the average interval between eruptions has been 600 years. The most recent 
eruption occurred about 200 years ago (Miller 1989). Geologic evidence indicates that large 
eruptions from Mount Shasta are similar to the 1980 eruption of Mount St. Helens in Washington 
in that they involve explosive eruptions and are accompanied by large debris avalanches that 
inundate large areas up to several tens of kilometers away from the volcanic cone (Crandell et al. 
1984). Evidence of the associated volcanic history can only be traced back to the Eocene Age; 
before that the geologic history and formations are similar to the Klamath Mountains. 
Three A-P Act zoned active faults are located within the province: the Cedar Mountain, Hat 
Creek, and McArthur faults, all of which make up the boundary between the Cascade Range 
Province and the Modoc Plateau. Each of these faults is capable of generating damaging 
earthquakes. In addition to these faults, movement of magma within the crust and volcanic 
eruptions can also be associated with damaging earthquakes.

Modoc Plateau Province
The Modoc Plateau is a table formed by thick accumulation of volcanic lava flows and tuff beds 
located to the east of the Cascades. It is an undulating plateau at an elevation of 4,000 to 6,000 
feet above sea level. Occasional lakes, marshes, and slow-moving streams cut this plateau. The 
province is bounded by the Cascade Range on the west and the Basin and Range Province on the 
east and south. The boundary with the Cascades is marked by the active normal faults2 of the 
Hat Creek fault zone. 

Coast Ranges Province
The Coast Ranges Province extends from Lompoc in the south to the Oregon border. Northwest-
trending ranges and intervening valleys that are generally parallel to major strike-slip faults (e.g., 
the San Andreas fault) and fold axes characterize the Coast Ranges. The mountains range from 
2,000 to 4,000 feet above sea level. The province is bounded to the east by the Great Valley; to 
the north by the South Fork Mountain fault, which marks the southern extent of the Klamath 
Mountains; to the south by the Transverse Ranges; and to the west by the Pacific Ocean. The 
province is naturally divided into North and South Coast Ranges by the depression that is 
occupied by San Francisco Bay and the Sacramento-San Joaquin River Delta. 

The Coast Ranges Province is traversed obliquely by the San Andreas fault system, a broad zone 
of strike-slip faulting3 that marks the boundary between the Pacific and North American plates. 
This system of faults, including the San Andreas fault itself, has been responsible for the 
majority of damaging earthquakes in California during historical time. 

In addition to the active strike-slip faults of the San Andreas system, the Coast Ranges also 
contain a number of active reverse or thrust faults4, most notably the blind or buried faults that 
mark the boundary between the Coast Ranges and the Great Valley. These faults have been 
responsible for several damaging earthquakes during historical time (Wakabayashi and Smith 
1994). The northern part of the Coast Ranges Province is dominated by landslide-prone 
formations.

San Francisco Bay Province
The San Francisco Bay area has a structurally controlled topography that consists primarily of 
north- to northwest-trending mountain ranges and intervening valleys that is characteristic of the 
Coast Ranges geomorphic province. This fabric is subparallel to the San Andreas fault. The 
Coast Ranges consist of the Mendocino Range to the north of San Francisco Bay, the Santa Cruz 
Mountains to the west of the Bay, and the Diablo Range to the east of the Bay. 

San Francisco Bay is a topographic trough formed by a combination of warping and faulting and 
is underlain by a down-dropped or tilted block (the Bay Block), which acts as a water gap in the 
Coast Ranges to allow the San Joaquin and Sacramento rivers to drain to the ocean. The Bay is 
about 56 miles long and from 3 to 5 miles wide. Constrictions divide the Bay into Suisun, San 
Pablo, and North and South San Francisco bays. The bay is relatively shallow with depths of less 
than 10 feet except in locations of drowned drainage channels. The deepest point is within the 
main channel through the Golden Gate, at a depth of approximately 345 feet below sea level.
The geology of the Bay area is made up primarily of three different geologic provinces: the 
Salinian block, Franciscan complex, and the Great Valley sequence. The Salinian block is 
located west of the San Andreas fault. It is composed primarily of granitic plutonic rocks that are 
similar to those found in the Sierra Nevada and are believed to be rocks of the Sierra Nevada 
batholith that have been displaced along the San Andreas fault. To the east of the San Andreas 
fault and bounded on the west by the Hayward fault is the Franciscan complex. The rocks of the 
Franciscan complex are prone to landslides. To the east of the Hayward fault is the Great Valley 
sequence. These rocks are also prone to landsliding.

The Great Valley Province
The Great Valley Province comprises two elongate northwest- to southeast-trending basins: the 
Sacramento basin to the northwest and the San Joaquin basin to the southeast. These basins are 
located between the Coast Ranges to the west and the Sierra Nevada to the east. The Sacramento 
and San Joaquin rivers drain the basins respectively and both drain to the ocean through San 
Francisco Bay. The province is approximately 450 miles long and 45 to 55 miles wide and 
ranges in elevation from below sea level to approximately 400 feet above sea level.
Four faults around the boundary of the Great Valley Province have been zoned under the A-P 
Act: the Buena Vista and Plieto-Wheeler Ridge faults, which make up the boundary with the 
Coast Ranges and Transverse Ranges to the west and south, respectively, and the Kern Front and 
White Wolf faults, which mark the boundary with the Sierra Nevada and eastern Transverse 
ranges, respectively.

Sierra Nevada Province
The Sierra Nevada Province is a tilted fault block approximately 400 miles long that forms a 
mountain range 40 to 100 miles wide. It is bound to the west by the Great Valley Province, to the 
north by the Cascade Range, to the east by the Basin and Range Province, and to the south by the 
Garlock fault along the northern margin of the Mojave Desert. The eastern face of the Sierra 
Nevada is the high, steep fault scarp of the Sierra Nevada fault and others that form the Sierra 
Nevada block. The western side of the Sierra Nevada is the low-sloping back side of the uplifted 
block containing rocks that disappear under the younger sediments of the Great Valley. Deep 
river canyons are cut into the western slope as they drain the Sierra Nevada. The northern 
boundary of the Sierra Nevada province is defined where the bedrock disappears under the 
Cenozoic volcanic cover of the Cascade Range. Elevations in the province range from 400 feet 
above sea level to 14,496 feet at the top of Mt. Whitney, the highest point in the lower 48 states.
The present topography of the Sierra Nevada is the result of extensive erosion by glaciers during 
the Holocene, and subsequent downcutting by high energy rivers, including the Kern, Kings, and 
Tuolumne. 

The Sierra Nevada has 10 A-P Act zoned faults, 1 within and 9 along the province boundary. 
The Cleveland Hill fault is within the province. The Garlock fault is along the Mojave Desert 
boundary. The Honey Lake, Little Lake, Sierra Nevada, Fort Sage, Hilton Creek, and Owens 
Valley faults are along the boundary with the Basin and Range Province. The Kern Front fault is 
located along the Great Valley boundary.

Basin and Range Province
The Basin and Range Province extends from eastern California to central Utah, from 
southernmost Oregon and Idaho to the north to southern Arizona and southwestern New Mexico 
and further into Mexico in the south. Within California the province includes a small portion in 
the northeastern corner of the state and a much larger area in the southern part of the state 
bordered by the Sierra Nevada to the west and the Mojave Desert to the south. Throughout the 
Basin and Range province, range-front faults can be found along the base of the ranges. Recent 
movements on these faults have elevated the ranges relative to the basins. Recent volcanic 
eruptions have left young cinder cones, craters, and lava flows. 

Numerous faults are zoned under the A-P Act within the Basin and Range Province: the Fort 
Sage, Hilton Creek, Sierra Nevada, and Honey Lake faults, which lie on the boundary with the 
Sierra Nevada, and the Death Valley fault, the Deep Springs fault, the Northern Death Valley 
fault, the Panamint Valley fault, the Surprise Valley fault, and the White Mountains fault.

Mojave Desert Province
The Mojave Desert is a region of isolated mountain ranges separated by expanses of desert 
plains. The Mojave Desert is located south of the Basin and Range Province and is bounded by 
the Garlock fault to the north, the Colorado River and the California-Nevada border to the east, 
and the San Gabriel and San Bernardino Mountains and the San Andreas fault to the southwest. 
The topography of the Mojave Desert is characterized by basins and ranges. However, the 
topography in the Mojave Desert is much more subdued than that of the Basin and Range 
Province. The ranges of the Mojave Desert are shorter and lower and the basins are wider. The 
topography is gentler than the sharp contrasts between ridge and valley of the Basin and Range 
Province. 

Numerous faults within the Mojave Desert Province have been zoned by the A-P Act: the 
Garlock fault along the Sierra Nevada and Basin and Range boundary, the North Frontal and 
Pinto Mountain faults along the Transverse Ranges boundary, the Burnt Mountain fault, the 
Eureka Peak fault, the Helendale fault, the Lenwood fault, the Mesquite Lake fault, the Pisgah-
Bullion fault, the Calico fault, the Kickapoo fault, the Manix fault, the Newberry fracture zone, 
and the Upper Johnson Valley fault. These faults have generated three damaging earthquakes in 
the last 20 years, including the 1992 Moment Magnitude 7.3 Landers and 1999 Moment 
Magnitude 7.1 Hector Mine earthquakes.

Transverse Ranges Provinces
The Transverse Ranges Province is a long, narrow, east-west-trending province that consists of a 
series of mountain ranges and valleys. The province is bordered to the south by the Peninsular 
Ranges. This boundary is defined by the Santa Monica fault between the Santa Monica 
Mountains and the Los Angeles Basin. The Mojave Desert borders this province to the north and 
the east and the Salton Trough/Colorado Desert Province to the southeast. 
Numerous active faults are zoned by the A-P Act in this province: the Pinto Mountain and North 
Frontal faults, which make up the Mojave Desert boundary, as well as the Cucamonga fault, the 
Red Mountain fault, the San Cayetano fault, the San Gabriel fault, the Raymond Hill fault, the 
San Andreas fault, the San Fernando fault, and the Ventura fault.

Los Angeles Basin Province
The Los Angeles Basin Province and the surrounding region are being deformed by several 
active faults that have generated a number of moderate-sized earthquakes, including the 1933 
Long Beach, 1971 San Fernando, 1987 Whittier Narrows, and 1994 Northridge events. Faulting 
is dominated by both strike-slip and thrust motions, either of which is capable of generating 
damaging earthquakes. 

The Los Angeles Basin Province is bounded by the San Andreas fault system to the east, the 
Transverse Ranges to the north, and the Continental Borderland and Peninsular Ranges 
provinces to the west and south, respectively. The tectonics of the Los Angeles Basin Province 
are transitional between those of the Transverse Ranges to the north and the Peninsular Ranges 
to the south. The Los Angeles Basin Province is an east-west elongate basin filled with Mesozoic 
and Cenozoic sediments that are highly deformed by a complex system of folds and thrust faults, 
many of which do not reach the earth's surface (so-called blind thrusts). In addition to these 
thrust faults, the Los Angeles Basin Province is traversed by a number of northwest-striking, 
right-lateral strike-slip faults, including the Newport-Inglewood, Elsinore, San Jacinto, and San 
Andreas faults. These strike-slip faults accommodate the majority of the plate motion between 
the Pacific and North American plates. The complex tectonics of the Los Angeles Basin 
Province are the result of a prominent left restraining bend ("The Big Bend") in the San Andreas 
fault as the fault exits Coachella Valley. This fault geometry creates a region of compression that 
is manifest as the folds and thrust faults of the Los Angeles Basin Province and the Transverse 
Ranges Province immediately to the north. 

Peninsular Ranges Province
The Peninsular Ranges Province consists of a series of ranges separated by longitudinal valleys 
that trend northwest to southeast, subparallel to faults of the San Andreas system. These 
mountains are composed of granitic rock intruded by metamorphic rocks similar to the Sierra 
Nevada. This province is located in the southwestern part of the state and is bounded to the north 
by the Transverse Ranges Province, to the east by the Salton Trough/Colorado Desert Province, 
to the south by Mexico, and to the west by the Continental Borderlands. 
Five northwest-trending faults within the Peninsular Ranges Province have been zoned by the 
A-P Act: the Elsinore fault, the Rose Canyon fault, the Newport-Inglewood fault, the San Jacinto 
fault, and the Whittier fault.

Salton Trough/Colorado Desert Province
The Salton Trough/Colorado Desert Province is a low-lying barren desert basin about 245 feet 
below sea level that contains the Salton Sea and the Imperial Desert. It is bordered by the San 
Andreas fault to the northeast and the San Jacinto fault to the southwest. The trough is a pull-
apart basin created by transform fault movement as the Peninsular Ranges pulled away from 
North America. 

Four faults within the province have been zoned by the A-P Act: the Brawley fault, the Imperial 
fault, the San Andreas fault, and the Superstition Hills fault.

Continental Borderlands
To the west, the Los Angeles Basin is bounded by the Continental Borderlands. The Continental 
Borderlands seismotectonic province is located in the offshore region of Southern California, 
extending from offshore Baja to the Channel Islands. This region is characterized by moderate 
levels of seismicity, with epicenters often being aligned along active fault structures. 

3.1.2.2 Geologic Hazards
The geologic environment of California comprises a number of potential geologic hazards, 
which are discussed in the following sections. The specific geologic hazards for each 
geomorphic province are described in Table 3.1-1.

Surface Fault Rupture 
Surface fault rupture is defined as slip on a fault plane that has propagated upwards to, and has 
offset or disturbed, the earth's surface. Offset on a fault intersecting the ground surface can create 
a discrete step or fault scarp if fault slip occurs on a single fault plane or within a narrow fault 
zone. If fault slip is accommodated over a broader area, then the deformation may manifest as a 
zone of fracturing and ground cracking with minor amounts of offset on individual fractures; 
however, the cumulative offset across the entire zone may be substantial. Surface faulting may 
also arise as a secondary effect from other geologic processes. Secondary surface faulting can be 
triggered by aquifer compaction and subsidence (e.g., Bawden et al. 2001) or by the effects of 
strong ground shaking triggering slip on neighboring faults. 

Surface fault rupture has occurred on a number of faults within the study region during the last 
10,000 years (Jennings 1994): the San Andreas fault in 1857 and 1906 (Wallace 1990), the 
Hayward fault in 1868 (Yu and Segal 1996), the Owen fault in 1872 (Lubetkin and Clark 1988), 
the San Fernando fault in 1971 (Barrows et al. 1973), the Imperial and Superstition Hills faults in 
1981 (Sharp, Rymer, and Lienkaemper 1986), the Landers fault zone in 1992 (Hart, Bryant, and 
Trieman 1993), and the Bullion Mountains-Lavic Lake faults in 1999 (U.S. Geological Survey, 
Southern California Earthquake Center, and California Division of Mines and Geology 2000) are 
examples of surface rupture associated with large, damaging earthquakes during historical time.
Areas subject to surface-faulting rupture hazard are zoned by the State of California under the A-
P Act (Hart 1994). Maps of areas of potential surface faulting are prepared by and available from 
California Geological Survey (formerly Division of Mines and Geology). These maps depict the 
most recently active traces of active faults and a zone around these traces within which future 
surface faulting may occur. All geomorphic provinces in California, with the exception of the 
Klamath Mountains, contain active faults that pose a surface-faulting hazard. Because of the high 
slip rates and high density of faults in the Los Angeles Basin and San Francisco Bay Area, these 
two regions have the highest likelihood of experiencing surface faulting in the future. 

Earthquake Ground Shaking
Strong earthquake ground shaking is probably the most important seismic hazard that can be 
expected almost anywhere in California. The amount of earthquake shaking at a particular site is 
a function of earthquake magnitude; the type of earthquake source (i.e., type of fault), distance 
between the site and the earthquake source, the geology of the site, and how the earthquake 
waves decrease or attenuate as they travel from their source to the site in question. The larger the 
earthquake and the shorter the distance between the earthquake source and the site, the greater 
the amount of shaking. The geologic materials through which the earthquake energy travels 
toward the site act to decrease, or attenuate, the amount of shaking. The amount of shaking is 
expressed in terms of "Peak Horizontal Acceleration" measured in percent of "g," the 
acceleration of gravity (approximately 9.81 feet per second squared).

California has experienced numerous damaging earthquakes during historical time (Stover and 
Coffman 1993; Toppozada et al. 2000). The 1868 earthquake on the Hayward fault caused 
widespread damage throughout the eastern San Francisco Bay Area; the 1906 earthquake on the 
San Andreas fault caused extensive damage in San Francisco and throughout Northern 
California. More recently, the 1989 Loma Prieta earthquake in the Santa Cruz Mountains and the 
1994 Northridge earthquake in San Fernando Valley caused widespread damage in the San 
Francisco Bay and Los Angeles Basin regions, respectively. A more comprehensive list of 
damaging earthquakes is provided in Table 3.1-2.

Liquefaction
Liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by 
earthquake shaking. Liquefaction and related phenomena have been responsible for tremendous 
amounts of damage by historical earthquakes around the world.

Liquefaction is the transformation of a granular material from a solid state into a liquefied state 
as a consequence of increased pore pressure and decreased effective stress (Youd 1973). 
Increased pore pressures in unconsolidated sediment, especially in western California, are most 
typically seismically induced deformation. Observed types of ground failure resulting from 
liquefaction can include sand boils, lateral spreads, ground settlement, ground cracking, and 
ground warping (Youd and Hoose 1978). Liquefaction occurs in saturated soils.

Lateral spreading is the lateral displacement of surficial blocks of sediment as the result of 
liquefaction in a subsurface. Once liquefaction transforms the subsurface layer into a fluidized 
mass, gravity may cause the mass to move downslope toward a cut slope or free face (such as a 
river channel or a canal). Lateral spreads most commonly occur on gentle slopes that range 
between 0.3° and 3°. When liquefaction occurs, the strength of the soil decreases and the ability 
of a soil deposit to support foundations for buildings or other structures is reduced. Liquefied soil 
also exerts higher pressure on retaining walls, which can cause them to tilt or slide. This 
movement can cause settlement of the retained soil and destruction of structures on the ground 
surface.

The potential for liquefaction is a function of having susceptible soils, shallow groundwater to 
create saturated conditions, and high enough ground shaking. If any of these conditions are 
lacking, then the potential for liquefaction is considered low.

Subsidence and Uplift
Land surface subsidence can result from both natural and human-made phenomena. Natural 
phenomena include subsidence resulting from tectonic deformations and seismically induced 
settlements (see liquefaction), soil subsidence due to consolidation, subsidence due to oxidation 
or dewatering of organic-rich soils, and subsidence related to subsurface cavities. Subsidence or 
settlement related to human activities includes subsidence caused by decreased pore pressure due 
to the withdrawal of subsurface fluids, including water and hydrocarbons. 

Subsidence and uplift are generally only considered a substantial hazard if they occur over 
human life time. Most of the mechanisms of subsidence and uplift described above occur over 
geologic time and, therefore, are not considered a potential hazard.

Expansive Soils
Expansive soils contain mixed-layer clay minerals that increase and decrease in volume on 
wetting and drying, respectively. Expansive soils are common throughout California and can 
cause damage to foundations and slabs unless properly treated during construction. Mixed layer 
clays and potentially expansive soils are present almost everywhere in California.

Mass Wasting
Mass wasting is downward movement of soils and rock under gravity, including landslides, rock 
falls, and debris flows. Mass wasting requires source materials, a slope, and a triggering 
mechanism. Source materials include fractured and weathered bedrock and loose soils. 
Triggering mechanisms include earthquake shaking, heavy rainfall, and erosion.

Volcanic Hazards
Potentially hazardous volcanic events can be categorized into three groups: flowage phenomena, 
eruption of tephra, and emission of volcanic gases. Flowage phenomena include debris 
avalanches and flows, pyroclastic flows5 and surges, directed blasts, lava flows, and floods. Any 
erupted volcanic material that moves down slope, such as lava, ash, water, and mud, away from 
the flanks of the volcano, or down adjacent valleys, constitutes flowage phenomena. The speed 
and distance at which they can flow is dependent on the composition of the erupted material, 
which varies for each volcano and type of flow. Most flowage phenomena are devastating, 
destroying everything in their path either by impact, burial, or ignition if the material is hot 
(Miller 1989). Floods occur if molten lava melts snow and ice on the volcano, consequently 
generating debris flows as lava ash and mud. Lahars, hot volcanic mud flows, are some of the 
most devastating consequences of volcanic activity. Such debris avalanches and flows, 
pyroclastic flows, and surges are difficult to avoid as their highly mobile, fluid nature allows 
them to move swiftly downslope away from their source (Miller 1989).

Tephra or ash fall consists of combinations of pumice, dense-rock material of various sizes, and 
mineral crystals. Ash fall is produced by explosive eruptions that propel material from a few 
meters to several tens of kilometers into the air (Miller 1989). Hazards related to tephra eruptions 
include high temperatures, burial, and impact of falling blocks. A substantial volume of tephra 
can collapse structures under its weight and, if it is hot, ignite fires. Hazards associated with ash 
fall decrease with distance from the volcano. The main hazard at considerable distances from the 
volcano would be the effects of ash on the respiratory system. Vehicles and machinery would be 
affected, possibly causing disruptions in transportation, communication, and electrical services 
(Miller 1989).

Gases are often emitted from vents preceding a volcanic eruption and can occur for hundreds or 
thousands of years after an eruption. Volcanic gases consist of steam with lesser amounts of 
carbon dioxide, sulfur, and chlorine. Gases are concentrated near vents but are also distributed 
downwind. As with tephra, hazards from volcanic gases decrease with distance from the vent. 
Oxidation of sulfur and chlorine gases can lead to the formation of sulfuric and hydrochloric acid 
aerosols. Such strong acid vapors can be harmful to plants, animals, and people if the vapors are 
in high concentrations (Miller 1989).

Tsunami and Seiche
A tsunami (Japanese word meaning "harbor wave") is a water wave or a series of waves 
generated by an impulsive displacement of the surface of the ocean or other body of water. 
Tsunamis can travel across oceanic basins and cause damage several thousand miles from their 
sources. Most tsunamis are caused by a rapid vertical movement along a break in the Earth's 
crust (i.e., a tectonic fault rupture on the bottom of the ocean resulting in the displacement of the 
column of water directly above it). The majority of tsunamis are triggered by earthquake rupture 
along subduction zones. The 1964 Alaska earthquake generated a tsunami that caused 
widespread damage along the coastline of Northern California. Paleoseismic investigations have 
also shown that tsunamis resulting from earthquakes on the subduction zone beneath Japan and 
the Cascadia subduction zone in the Pacific Northwest have also inundated the Pacific coast 
states (Atwater et al. 1995). 

A seiche is a periodic oscillation or "sloshing" of water in an enclosed basin such as San 
Francisco Bay. The period of oscillation can range from minutes to hours. 

Erosion
Erosion is the gradual wearing away of land by water, wind, and general weather conditions. As 
with weathering, erosion is a natural geological process, but more rapid soil erosion results from 
poor land use practices, leading to the loss of fertile topsoil and to the silting of dams, lakes, 
rivers, and harbors. 

Wind erosion can occur on any soil whose surface is dry, unprotected by vegetation (to bind it at 
root level and shelter the surface), and consists of light particles. The mechanisms include 
straightforward picking up of dust and soil particles by the airflow and the dislodging or abrasion 
of surface material by the impact of particles already airborne. 

Three classes of erosion by water exist: (1) splash erosion occurs when raindrops strike bare soil, 
causing it to splash as mud, to flow into spaces in the soil, and to turn the upper layer of soil into 
a structureless, compacted mass that dries with a hard, largely impermeable crust; (2) surface 
flow occurs when soil is removed with surface runoff during heavy rain; and (3) channelized 
flow occurs when a flowing mixture of water and soil cuts a channel, which is then deepened by 
further scouring.

3.1.2.3 Soils
The formation of a soil profile is influenced by five primary factors: climate, topography, soil 
parent material, biotic influence, and time. Because a wide variation may exist between these 
factors, even within a relatively small area, any regionwide or statewide summary must be 
somewhat imprecise and inclusive. The soils descriptions in the following sections are intended 
to be general in nature and follow the taxonomic terminology used by the U.S. Department of 
Agriculture. Figure 3.1-2 is a map of California divided into ecological subregions that reflect 
differences due primarily to variations in climate, topographic relief, and the geographic 
relationships between subregions and the Pacific Ocean. The following text is modified from 
Ecological Subregions of California: Section and Subsection Descriptions (Miles and Goudey 
1997).

Central California Coast
This section consists of mountains, hills, valleys, and plains in the southern Coast Ranges of 
California. It is close enough to the Pacific Ocean for the climate to be modified greatly by 
marine influence. This section is within the Coast Ranges Province (Figure 3.1-1). The bedrock 
is primarily Cenozoic marine and nonmarine sedimentary rocks and Mesozoic granitic and 
ultramafic rocks mantled by alluvial and colluvial deposits. Soils are Alfisols, Entisols, 
Inceptisols, Mollisols, Ultisols, and Vertisols. Table 3.1-3 provides a brief description of soil 
taxonomic terminology. Soil temperature regimes are isomesic, mesic, or thermic; soil moisture 
regimes are xeric, udic, ustic, or aquic. 

Southern California Coast
This section contains mountains, hills, valleys, and plains of the Transverse Ranges and of the 
Peninsular Ranges that are close enough to the Pacific Ocean for the climate to be modified 
greatly by marine influence. This section is within both the Transverse and Peninsular Ranges 
Provinces. The landscape consists of narrow ranges and broad fault blocks, alluviated lowlands, 
and coastal terraces. Cenozoic marine and nonmarine sedimentary rocks and alluvial deposits 
underlie the soils of this section. Soils are Alfisols, Entisols, Inceptisols, Mollisols, Ultisols, and 
Vertisols in combination with thermic, isothermic, or mesic soil temperature regimes and xeric, 
ustic, or aquic soil moisture regimes. 

Great Valley
This section contains the alluvial plains of Sacramento and San Joaquin valleys. Summers are 
hot and dry and winters are mild. Oceanic influence on climate is slight in the middle of the 
Great Valley, which receives some marine air through Carquinez Strait, but little at the north and 
south ends of the valley. This section coincides with the low fluviatile plain of the Great Valley 
Province. Holocene and Pleistocene alluvial deposits cover nearly all of this ecological section. 
Soil orders found here are Alfisols, Aridisols, Entisols, Histisols, Inceptisols, Mollisols, and 
Vertisols. The soil temperature regime is thermic, and xeric, aquic, or aridic soil moisture 
regimes are common, depending on soil profile location. 

Northern California Coast
This section encompasses mountains, hills, valleys, and plains in the Northern California Coast 
Ranges and small parts of the Klamath Mountains that are close enough to the Pacific Ocean for 
the climate to be modified greatly by marine influence. Summers are characterized by fog, cool 
temperatures, and higher humidity than found inland. Like the Central California Coast section 
described above, the Northern California Coast lies within the Coast Ranges geomorphic 
province typified by somewhat linear ranges, with rounded crests of subequal height separated 
by parallel valleys. Late Mesozoic rocks of the Franciscan Formation and shelf and slope 
sedimentary rocks have been folded, faulted, and metamorphosed in this section. Soils on the 
north coast are Alfisols, Inceptisols, Mollisols, Spodosols (Pygmy Forest), Ultisols, and 
Vertisols. Typically, soil temperature regimes are isomesic, mesic or thermic, and soil moisture 
regimes are aquic, udic, ustic, or xeric (moist end of range). 

Klamath Mountains
The Klamath Mountains section is between the Southern Cascade Mountains and the Coast 
Ranges mountains. Its southern limit is the northern end of the Great Valley. This section 
coincides with the Klamath Mountains geomorphic province, an uplifted and dissected peneplain 
formed on strong rocks with extensive monadnock ranges. Mountains in this section have 
accordant or subequal summits and are generally, but not consistently, aligned north to south. 
Paleozoic sedimentary and volcanic rocks, and Mesozoic ultramafic, granitic, sedimentary, and 
volcanic rocks are found here. Soils are Alfisols, Entisols, Inceptisols, Mollisols, and Ultisols in 
combination with thermic, mesic, frigid, or cryic soil temperature regimes and xeric or aquic soil 
moisture regimes. 

Northern California Coast Ranges
This section is the interior part of the Northern California Coast Ranges mountains, north of 
Carquinez Strait. Marine air modifies winter and summer temperatures, but the section is far 
enough inland from the coast that oceanic effects are greatly diminished and less prevalent than 
in the Northern California Coast section. This section lies within the Coast Ranges geomorphic 
province of parallel ranges, folded, faulted, and metamorphosed strata. Late Mesozoic rocks of 
the Franciscan Formation, Mesozic ultramafic rocks, and Cenozoic volcanic rocks are the 
common bedrock lithologies in this section. Soil orders found in this ecoregion are Alfisols, 
Entisols, Inceptisols, and Mollisols in combination with frigid, mesic, or thermic soil temperature 
regimes and a xeric soil moisture regime. 

Northern California Interior Coast Ranges
This section is the southeastern edge of the Northern California Coast Ranges mountains (south 
of Cache Creek) and hills and terraces along the west side and north end of Sacramento Valley. 
Like the above section, this section is part of the Coast Ranges geomorphic province. 
Bedrock in the Northern California Interior Coast Ranges is late Mesozoic marine shelf and 
slope sedimentary deposits. Soils are Alfisols, Inceptisols, Mollisols, and Vertisols in 
combination with thermic soil temperature regime and xeric soil moisture regime. 

Southern Cascades
This section comprises the southern Cascade Ranges. The crest of the mountain chain is aligned 
toward the north-northwest between the Sierra Nevada and Mount Shasta and toward the north 
from Mount Shasta northward. The landscape in this section is dominated by volcanic mountains 
that are variously eroded. This section lies completely within the Cascade Ranges geomorphic 
province of California. Rocks in this section are Cenozoic volcanic rocks and alluvial deposits of 
these same rocks. 

Numerous soil orders have been described in this section: Alfisols, Andisols, Aridisols, Entisols, 
Inceptisols, Mollisols, Ultisols, and Vertisols. The soil temperature regime is mesic, frigid, or 
cryic, and the soil moisture regime is xeric, aridic, or aquic. 

Sierra Nevada
This section is the temperate to very cold parts of the Sierra Nevada, which is a north-northwest-
trending tilt-block mountain range with a steep eastern side and gentler sloping western side. 
This ecoregion lies within the Sierra Nevada Range geomorphic province. Mesozoic granitic and 
ultramafic rocks, Paleozoic and Mesozoic strongly metamorphosed sedimentary and volcanic 
rocks, and Cenozoic volcanic rocks are present in this range. Locally glacial and fluvial deposits 
are present as well. Soils are Alfisols, Andisols, Aridisols, Entisols, Inceptisols, Mollisols, and 
Ultisols in combination with mesic, frigid, or cryic soil temperature regimes and xeric, udic, 
aridic, or aquic soil moisture regimes. 

Sierra Nevada Foothills
This section comprises the foothills on the western side of the Sierra Nevada, and the 
southwestern end of the Cascade Ranges, adjacent to the Great Valley. Summers are hot and dry 
and winters are mild. This ecoregion lies within the Sierra Nevada Range geomorphic province. 
Mesozoic sedimentary, granitic, volcanic, and ultramafic bedrock is present. Soil orders f