HomeMy WebLinkAboutR3622 Adopting Safety Element of the General Plan/'�- SOLUTION NO. 3622(1978 Series'``)
A' RESO\�xr,`ION OF THE COUN IL OF THE CITY, SAN
LUIS OBISPO PROVING AND ADOPTING THE SAFETY ELEMENT
OF THE GENERAL PLAN
WHEREAS; Section 65302.1 of the California Government Code requires that the City
prepare and adopt a Safety Element to its General Plan; and
WHEREAS; In May, 19789 the Environmental Review Committee evaluated the proposed
Safety Element and found that its implementation would not have a signi-
cant adverse effect on the environment; and
WHEREAS; The City Planning Commission held public hearings during June and July to
review the draft Safety Element report and maps; and
WHEREAS; On July 12, 1978, the Planning Commission recommended that the Council
adopt the Safety Element subject to certain amendments to plan policies.
NOW THEREFORE BE IT RESOLVED by the Council of the City of San Luis Obispo as follows:
1. This Council, having held a duly noticed public hearing this date, and having
read and considered the draft Safety Element dated July, 1978, together with the
attached comments and recommendations of the Planning Commission, hereby approves
and adopts said draft together with said comments and recommendations as the
Safety Element of the General Plan of the City of San Luis Obispo.
2. A copy of the adopted Safety Element shall be maintained on file in the office of
the Community Developement Department for public use during normal business hours.
On motion of Councilman Jorgensen seconds y Councilman Settle ,
and on the following roll call vote:
AYES: Councilmen Jorgensen;,,Petterson, Settle and Mayor Schwartz
NOES: None
ABSENT: Councilman Dunin
the foregoing Resolution was passed and
ATTEST:
erk J.H.
Approved as to form:
Approved as to content:
miM strative Officer =9-rml
Community De I
e opmen Department
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PREFACE
On June 5, 1975, the San Luis Obispo County and Cities
Area Planning Coordinating Council (now the San Luis
Obispo County Area Council of Governments) authorized
Envicom Corporation to proceed with studies for a Regional
Safety Element in accordance with a joint powers agree-
ment among the County of San Luis Obispo and the cities
of Arroyo Grande, Grover City, Morro Bay, Paso Robles,
Pismo Beach and San Luis Obispo. The result was a two-
part document summarizing the work performed by Envicom
Corporation and the Area Planning Council's member
jurisdictions.
This document, the City of San Luis Obispo Safety Element,
was derived in large part from the Regional Safety
Element. It includes the Technical Report (Part II) from
the regional study. The first part of the city Safety
Element, the Policy Report, reflects Envicom's work as
it pertains to the city, and as revised by the staff of
the city's Community Development Department and the City
Council. This final documentation of studies has been
prepared in accordance with California Government Code
Section 65302.1.
CONTENTS SUMMARY
INTRODUCTION . . . . . . ... ... . . . . . . . .
. . . . . .
POLICY REPORT (PART I)
Table of Contents
Existing Conditions . . . . . . . . . .
. . . . . 1.1
Relationship to Other General Plan Elements . . . 1.7
Goals, Policies and Recommended Action.
. . . . . 1.10
TECHNICAL REPORT (PART II)
Table of Contents
Introduction . . . . . . . . . . . . .
. . . . . 2.1
Fire Hazards Analysis . . . . . . . . .
. . . . . 2.2
Flood Hazards Analysis . . . . . . . .
. . . . . 2.45
Geologic Hazards Analysis . . . . . . .
. . . . . 2.55
Radiation Hazards . . . . . . . . . . .
. . . . . 2.64
Emergency Preparedness . . . . . . . .
. . . . . 2.09
References . . . . . . . . . . . . . .
. . . . . R-1
* NATURAL HAZARDS MAPS
(*Available from the city's Community Development
Department)
W
INTRODUCTION
What's this about?
Earthquakes, landslides, fires, floods, radioactive
spills -- these things happen or could happen in San
Luis Obispo. They can mean injury, death, destruction
and economic chaos for a few or many. Although we
can't prevent them, we can do a lot to reduce the
damage they do. If we plan for them.
That's what this document is: the city's plan to reduce
the threat from these natural and man -caused disasters
and to be as ready as possible to respond when they do
occur. This plan includes technical studies of the
dangers involved, studies that seek to define and locate
the threat as precisely as possible. It also includes
policies designed to make San Luis Obispo a safer place
to live. It does this by helping the city avoid dangerous
situations where possible, prepare for the unavoidable,
and assure that such vital facilities as hospitals are
in good enough shape after a disaster to treat the
injured and keep the community operating.
By accounting for hazards in planning the use of land,
in regulating construction and in making other policy
decisions, the city can save lives and property. That's
why this safety plan is part of the city's general plan.
It's one of several "elements" that make up the total
general plan.
This City of San Luis Obispo Safety Element is concerned
with several specific potential hazards: wildland fire,
urban fire, natural flooding, dam -related flooding,
geologic hazards and radiation. (Geologic hazards are
treated generally in this element, since they are dealt
with in detail in tite city's Seismic Safety Element.)
This element also is concerned with the capabilities of the
various emergency -response agencies serving the city. These
agencies must be ready to act, and act effectively.
U
.Two aspects of public safety are outside the scope of this
document: crime and accidents. Ilowever, this Safety lilement
relates indirectly to those two concerns because it deals with
emergency preparedness. Policies that improve the response of
police and firefighters to major disasters should help improve
their response to crime and accidents also.
The element deals mainly, of course, with ,
San Luis Obispo's urban area. But disasters
don't acknowledge city limit lines, so the city and this
element also must deal with hazards in the surrounding area.
For the purposes of studying and regulating the use of
land, the geographical extent of the city's concern is
what's called the city's "planning area." This is roughly
the area of the San Luis Creek watershed north of Daven-
port Creek, extending several miles from the city into
Cuesta Canyon, and into the Chorro, Los Osos and Edna
valleys. But some potential threats to the city come from
sources even outside the planning area .-- such as from the
Diablo Canyon nuclear power plant. And some city facilities,
such as Whale Rock Reservoir, are some distance from the
city. This element also deals with those.
It's required.
The city is required by state law to consider geologic,
fire and other hazards in its planning program. As part of
the recent, growing interest in planning, the California
Legislature made local governments responsible for identify-
ing and evaluating these hazards and for reducing the risks
they create. Specific authority for a safety element is
derived from Government Code Section 65302.1 which requires
the following:
"A safety element for the protection of the
community from fires and geologic hazards in-
cluding features necessary for such protection
as evacuation routes, peak load water supply
requirements, minimum road widths, cle:n-ances
around structures and goologic hazard mapping
in areas of known geologic hazard."
The premise behind this requirement is that if govern-
ment is to ensure public safety and welfare, it must
recognize the dangers posed by fire, flooding, earth-
quake and other hazards and must plan accordingly. The
rationale for preparing a safety element is that it will
be easier to take public action to make a city safer if
precise information about hazards is available and if
there is an official framework for taking appropriate
action.
What should be done with this document?
This document is intended to serve as an official guide
for the city's council members, planning commissioners
and staff members, as -well as for citizens and private
organizations concerned with public safety in San Luis
Obispo. It is intended to give city government a
uniform policy and direction in working to minimize
risk to life and property.
The heart of the element is in its goals, policies and
recommendations for action. These guidelines should be
used in conjunction with other policies contained in
the city's general plan and should play a major role
in determining the future use of land. After the Safety
Element is adopted, it should be updated regularly.
The element is in two parts. The first part, the
Policy Report, deals with ways to reduce risk in the
city. The second part, the Technical Report, analyzes
the risks created by potential hazards in the city
and county and estimates the magnitude of the events
that should be anticipated.
Part 1's policies rely on Part 11's technical estimates
of how big, how frequent and where the hazards will be.
These estimates are derived from sciences, such as
seismology and fire ecology, which are relatively young,
and in which much remains to be learned. The city believes
we should incorporate what we know today into the planning
process and not wait until we know all we would like
to know.
POLICY
PART I: POLICY REPORT
TABLE OF CONTENTS
I. EXISTING CONDITIONS
A. Types of Hazards ....... :................. 1.1
B. Summary of Technical Conclusions ......... 1.1
1. Fire Hazards...... ... ......... 1.2
2. Flood Hazards ....................... 1.2
3. Geologic Hazards .................... 1.2
a. Public Utilities ............... 1.3
b. Dam Safety ..................... 1.3
4. Radiation Hazards ................... 1.3
S. Emergency Preparedness ............... 1.3
C. Risk ..................................... 1.4
11. RELATIONSHIP TO OTHER GENERAL PLAN ELEMENTS
A. General ............................... 1.7
B. Seismic Safety Element ................... 1.7
C. Land Use Element ......................... 1.7
D. Circulation Element ...................... 1.8
E. Open Space Element ....................... 1.9
III. GOALS, POLICIES AND RECOMMENDED ACTION
A. Organization of Planning Recommendations . 1.10
B. Goals .................................... 1.10
C. Policies ................................. 1.10
D. Implementation Measures .................. 1.11
r
LIST OF TABLES
No. Page
I Classification of Critical Facilities ......... 1.6
2 Summary of Risk Criteria ...................... 1,1i
3 Land -Use Policy Summary ....................... 1.8
EXISTING CONDITIONS
seiches (oscillating waves in lakes or reservoirs).
A. Types of Hazards
The potentially damaging events discussed above can, of
course, damage man-made structures. The potential for
Four basic groups of hazards are considered in this Safety
structural failure is termed a structural hazard.
Element: fire, flooding, geologic and radiation hazards.
This includes not only damage to structures themselves,
bat also damage or injury from moving objects in,
Fires in undeveloped areas involving accumulated brush
on or next to a structure. Of particular
concern in the Safety Element is the effect of seismic
and other vegetation, termed "wildland fires," are a
activity on important public utilities such as gas, electric
significant threat to San Luis Obispo. Wildland fires are
and water lines. The relationship between seismic hazards
treated separately from "urban fires," which occur
and dam safety is also considered in this element.
in built-up areas and involve primarily structures.
Automobile fires and small -to -medium-sized brush fires
An analysis of radiation hazards is not specifically re -
within urban areas are included in the urban fire
quired by the Government Code, but is included in the
category. These two categories of fire hazard are the
San Luis Obispo Safety Element because of Pacific Gas and
types considered in this document.
Electric Company's nuclear power plant at Diablo Canyon.
Unlike the analyses of fire, flooding and geologic hazards,
Flood hazards in and near the city are also considered in
the evaluation of radiation hazards does not include an
two categories: natural flooding and dam inundation.
estimate of risk. The potential for a hazardous situation
"Natural flooding" means the inundation of developed
arises from the presence and transport of highly radioactive
areas that occurs when a storm causes streams or storm
nuclear fuel. This hazard is recognized by utilities,
drains to overflow. Dam inundation is the downstream
government agencies and private citizens, and numerous
flooding that would occur if a dam broke or overflowed.
steps have been taken to minimize the risk of a release of
high levels of radiation. Yet some level of risk, however
The discussion of seismic (earthquake) and geologic
small, does exist. It is appropriate to plan for an
hazards in the Safety Element consists primarily of a
accident. The emphasis of this element with respect to
synopsis of the detailed discussion contained in the
radiation hazards is on emergency -response capabilities
Seismic SafetyElement. That discussion .groups earth-
rather than on risk.
quake hazards in a cause -and -effect classification which
is the basis for the order of their consideration. Farth-
More in-depth discussions of radiation and the terminology
quakes originate as shock waves generated by movement
of fire, flooding and geologic hazards are presented in the
along an active fault. The primary seismic hazards are
Technical Report.
ground shaking and the potential for ground rupture along
the surface trace of the fault. Secondary seismic hazards
R. Summary of 'Technical Conclusions
result from the interaction of ground shaking with exist-
ing soil and bedrock conditions, and include liquefaction,
The foundation of the Safety Element is its technical evalna-
settl'ement, landslides, tsunamis or "tidal waves," and
tion of fire, flooding and geologic hazards. The analyses
of radiation hazards and emergency -response capability also
form part of the basis of the policies contained in this
2. Flood Hazards
report. Major conclusions from the different technical
analyses, updated to reflect developments since the Tech-
a. The potential for natural flooding in the city exists alum;
nical Report was completed, are as follows:
the length of San Luis Creek and along its major tributaries:
Stenner Creek, Brizziolari Creek and Prefumo Creek. Areas
1. Fire Hazards
which might be particularly hard hit are along San Luis
Creek -- downtown and between lliguera/South• Iligitera Street
a. The city is confronted with one of the more hazardous
and the freeway,
wildland fire situations in the county because of its
location near the foothills of the Santa Lucia Mountains
b. Lakeside residential areas in the Laguna neighborhood have
and the Irish Hills. There is great danger from fire in the
in the past been subject to flooding. But in 1974 a
foothills northeast and southwest of the city and on Cerro
larger culvert was built under Madonna Road at the southeast
San Luis Obispo, Bishop Peak, Chumash Peak and Islay Hill.
end of Laguna Lake. This culvert was designed to drain the
lake fast enough to prevent future flooding of lakeshore
b. The city faces complex urban fire hazards ranging
areas.
from industrial fires to the hazards of older and high -
occupancy dwellings in the downtown area and near the
c. The Broad Street -Lincoln Street area near the point where
Cal Poly campus.
Stenner and Old Garden creeks meet has been subject to flooding
in the past. A new culvert under Highway 101, nearing
c. Specific urban fire hazards in the city include the
completion, is designed to handle 100-year flows, and should
following: (1) insufficient fire flows in numerous areas
help to relieve the problem in this area and upstream.
throughout the city, (2) potential response delays caused
by traffic congestion, (3) potential response delays
3. Geologic Hazards
caused by topography and man-made features such as the
railroad and Highway 101, (4) hazards associated with
The geologic hazards analysis contained in the Technical
community infrastructure systems such as gas and electric
Report is, for the most part, a synopsis of the detailed
lines, (5) inadequate service to the southern end of the
analyses presented in the 1975 San Luis Obispo Seismic
South lliguera Street area. (It takes a fire engine more
Safety Element. In addition to the summary of primary and
than four -minutes -- the recommended response time -- to
secondary seismic hazards, the Safety Element's technical
get to the end of South lliguera.)
analysis provides a brief discussion of the effects of
seismic hazards on utilities and of the relationship between
d. A fire station being built at the corner of Madonna
geologic hazards and dam safety. Summary conclusions of
Road and Los Osos Valley Road is expected to be completed
these structural hazards are presented below. 'Chose wishiul,
by April 1978. This station will provide adequate fire
to review the seismic hazard summary are referred to the
protection for the Laguna area, which has been outside the
Safety Element Technical Report, pp. 54-60. The following
four -minute response zone. Engines from this station also
conclusions are generalized, and are not based on iuvestiga-
could reach the residential and industrial areas along
tions of specific structures within the city. Such inves-
South lliguera Street in less than four minutes if a
tigations are, of course, necessary before specific con -
bridge were built over San Luis Creek to link Los Osos
cluSionS regita•ding the Safety of ;ally illdiviihwl siraclure
Valley Road with South Higuera.
caa be made.
a. Public Utilities. On the basis of experience gained from
the San Fernando earthquake of 1971, the following general
conclusions may be drawn regarding the behavior of public
utility structures during a major earthquake. Any com-
parison of the damage at San Fernando and expected damage
In San Luis Obispo should be taken in the context that
most of the significant damage in the San Fernando area
was along or near the zone of fault rupture or in areas
of very intense ground shaking with some liquefaction.
General conclusions are as follows:
"1. Modern steel water -storage tanks and old water -reser-
voir roof structures performed poorly. Old hydraulic
earth -fill dams, not designed to resist earthquake loads,
performed poorly, with two experiencing near -failure.
2. Underground conduits for water, sewage, storm water,
gas and petroleum were damaged, mainly because of perman-
ent differential ground movements rather than due to
vibration. Effective preventive measures in this field
will be difficult to develop. Potential ground -movement
areas should be identified.
3. Large underground structures such as the Finished
Water Reservoir at the Joseph Jensen Filtration Pant
require special attention. Apparently, they act much
like structures above grade. More research is needed,
along with development of design criteria.
4. Electrical power equipment performed poorly. Fail-
ures were due to inadequate anchorage and bracing and, in
some cases, to inadequate aseismic details within the
equipment.
S. Communication equipment in the telephone industry
performed well except for several faillures due to inad-
equate or poorly detailed and constructed anchorages and
bracing." (Moran and Duke, 1975).
1.3
b. Dam Safe
(1) Studies for the County Seismic Safety Element indi-
cate surface rupture along an active fault through a dam
structure itself is not a significant hazard to any major
dam of concern to the city.
(2) T'he ability of major dams in the area to withstand
expected ground shaking in the event of a large -magnitude
earthquake has not been determined. A city -funded seismic
exudy of the federally -owned Salinas Dam at Santa Margarita
Reservoir -- from which the city gets most of its water -- is
under way. Older structures are of more concern than more
recent, compacted -fill or concrete -arch structures.
(3) Overtopping of impounded water as a result of massive
landsliding into a full or nearly full reservoir is a
significant potential hazard at the city's Whale Rock Res-
ervoir at Cayucos and at the privately owned Righetti Reser-
voir southeast of the city.
4. Radiation Hazards
Since the technical analysis of radiation hazards contained
in Part 11 of this document is a general background state-
ment on radiation and nuclear power plants, no major con-
clusions specific to'San Luis Obispo are provided. It is
assumed that an accidental release of lu.rmful levels of
radiation is possible, despite the fact that such an accident
is unlikeiy. Planning for such an accident •is prudent and
necessary for public safety.
Emergency Preparedness
a. The county's peacetime emergency organizations rely
heavily on the concept of mutual aid for responding to major
disasters. While the basic planning framework and emergency
inventories should be adequate for most disasters, they
may prove insufficient when confronted with a major earth-
quake, widespread flooding or a large fire.
b. Mutual aid in the city and county provides economical
emergency services, but is less than optimally efficient,
particularly for the fire -fighting organizations.
c. Emergency communications between different agencies
cooperating under mutual aid agreements may be impaired
in a major disaster by the lack of a common emergency -
communication channel.
C. Risk
Given that certain natural hazards exist in San Luis
Obispo, it is necessary to decide whether the risks
these hazards present are acceptable or whether action
is necessary to reduce the level of risk. The California
Council on Intergovernmental Relations defines "risk"
from natural and man-made hazards in three categories:
1. Acceptable risk: The level of risk below
which no specific action by government is deemed
to be necessary.
2. Unacceptable risk: The level of risk above
which specific action by government is deemed to
be necessary to protect life and property.
3. Avoidable risk: A risk which need not be
taken ecause in ividual or public goals can be
achieved at the same, or less, total "cost" by
other means without taking the risk.
To determine levels of acceptable risk is to provide an
answer to the question "flow safe is safe enough?" No
environment is perfectly hazard -free. Natural and
man-made hazards of some kind are always present, especially
in urban environments. However, some hazards cause only
minimal loss or occur so rarely that they need not be planned
for at the community level. On the other hand, some events
occur often enough, are large enough, and have enough potential
for major disruption of the community to warrant a community -
wide response to the risk. Deciding the level of response
to natural hazards such as fire and flooding is a public
process which involves making a judgment, either explicit or
implicit, about acceptable risk. Scientific expertise can
determine the magnitude of the hazard and estimate the probable
effects, but it cannot decide for the public how much risk
to assume.
The central concept used in determining levels of accept-
able risk is the definition of natural events in terms of
magnitude and frequency. The magnitude of an event refers
to its size. Examples are the height of flood waters, the
rating of an earthquake on the Richter scale, or the number
of acres burned in a wildland fire. The frequency of an
event refers to the number of times it occurs during a
certain period of time. The relationship between magnitude
and frequency is inverse. That is, the less often an event
occurs, the greater is its size and potential impact. For
example, rainstorms occur annually in San Luis Obispo County,
but most often they are of low magnitude and do not seriously
threaten residents. However, on infrequent occasions, as
in January and February 1969, a storm of large magnitude
passes over the region and results in a dangerous flood. A
way of summarizing this idea with respect to an earthquake
is that the longer it waits, the bigger it will he.*
There is one important difference between flooding and
earthquakes, however. flooding is the result of a random
combination of meteorological events, whereas current geologic
theory indicates that the buildup of strain along a particular
fault system is nearly constant, and the periodic release of
that strain in the form of an earthquake is apt to be regular.
The magnitude -frequency concept is involved in the decisions
regarding acceptable risk in that the community must judge
what magnitude of event should be planned for. That judg-
ment is based on the frequency or recurrence interval of
the hazardous event. A description of the magnitude and
other characteristics of the event are developed through
a technical analysis. This information allows planners
and engineers to develop ways to reduce losses and to
design structures to provide protection up to the level
of acceptable risk. In this sense, the magnitude of
earthquake or flood used in defining acceptable risk may
be thought of as a "design earthquake" or "design flood."
The determination of acceptable risk from hazardous events
also involves differentiating among man-made structures
according to their potential effect on the loss of life
and their importance in terms of emergency response and
continued community functioning. In the hours immediately
following the 1971 San Fernando earthquake in Southern
California, emergency services were impaired by damage to
police and fire stations, communication networks and
utility lines.. A number of major hospitals in the area
were seriously damaged and were unable to continue func-
tioning at the time they were needed most. These facili-
ties and others are vital to the community's ability to
respond to a major disaster and to minimize loss of life
and property. The experience in San Fernando emphasizes
the need to provide these "critical facilities" a higher
level of protection from natural hazards than is provided
for noncritical structures. The city's Seismic Safety
Element contains a recommended list of critical facilities
based on potential effects on loss of life and importance
to continued community functioning. This list, slightly revised,
is reproduced here as Table 1.
By considering both the natural event and the type of land
use or facility, a framework for making risk decisions
can be established. Table 2 provides a summary of risk
1.5
criteria used to formulate the policies stated in the next
section.
TABLE 1
CLASSIFICATION OF CRITICAL FACILITIES
Land Use/Facility Safety Characteristic
Potential Emergency Required for
Effect on Response Community
Loss of Life Functioning
Developed Land
PUBLIC AND SEMI-
PUBLIC USES
- Hospitals
X X X
- Schools/colleges
X
- Civil defense quarters
X X
Fire E police stations
X X
- Government offices
X X
- Fossil -fuel power plants
X X
- Nuclear power plants
X X X
- Gas $ electric lines
and stations
X X
- Dams
X X X
-, Radio/TV/microwave
centers $ lines
X X
- Aqueducts B pipelines
X X
- Sewage treatment facilities
X X
- Gas stations
X X
- Electrical substations
X X
- Waterworks
X X
- Radio F, TV stations
X X
- Major roads and highway
bridges
X X
- Railroads
X
- Airports
X
Auditoriums L other
places of public assembly X
N
TABLE 2
SUMMARY OF RISK CRITERIA
Hazard
Risk Criteria
Wildland
Risk categories:
Fire
Extreme, Nigh,
Moderate, Low
Nil
Urban
Generalized categories not
Fire
recommended; building -by -
building evaluations
necessary.
Natural
100-year floodplain.
Flooding
Dam
Office of Emergency
Inundation
Services; Dam inundation
maps.
Seismic/ See Seismic Safety
Geologic f:l eunent .
Hazards
1 Risk evaluations for radiation hazards are beyond
the scope of this element.
11.. RELATIONSHIP TO OTIIER GENERAL PLAN ELEMENTS
A. General
The technical data compiled in the preparation of the
Safety Element and presented in Part II should be used
by persons engaged in the planning process. While the
data are generalized in some respects and require fur-
ther detailed studies, the findings of the element should
be reflected in other general plan elements and in
controls placed on developments within the city's plan-
ning area.
The Safety Element is most closely related to the Seismic
Safety, Land Use, Circulation and Open Space elements.
An extensively revised Land Use Element was adopted by
the city in January 1977. The city's Seismic Safety
Element, adopted in September 1975, is relatively up-to-
date and only minor revisions are expected. The Circulation
Element, adopted in 1972, needs major revisions. The
Open Space Element, adopted in 1973-74, also requires
extensive revision. Key points of this Safety Element
were considered in revising the Land Use Element and
will be considered when other elements are revised.
B. Seismic Safety Element
In terms of legislative intent, the Seismic Safety and
Safety elements are probably the most similar of the
state -mandated general plan elements. The Seismic
Safety Element introduces earthquake hazards into the
planning process, and the Safety Element extends the
introduction to include fire, flooding and other geologic
hazards. The Safety Element also includes a discussion
of emergency preparedness as related to all types of
peacetime safety hazards, including seismic hazards.
The similarity between these two elements is reflected
by the inclusion of a summary of the Seismic Safety
1,7
Element in the Safety Element Technical Report and by the
safety policies presented in this part of the Safety Element.
These elements can best be used by planners as a single unit
which defines the natural hazards (and some man -caused
hazards) confronting the city. There is some overlap in the
recommended policies of these elements. It is advisable to
review these elements together to determine applicable policies
on mitigating hazards.
C. Land Use Element
The Urban Land Use Element will be influenced most directly
by the recommendations of Policy 3.0 (pages 1.10 and 1.12)
to regulate land use in areas of significant natural hazard.
Although the city has the potential for considerable growth,
this growth could be located to minimize danger from natural
hazards. The objective is to use the information contained
in this element to reduce the risk to life, to reduce the
probability of property loss, and to ensure that critical
public facilities can continue to function during and after
a major disaster. Table 3 presents a summary of land -use
policies for different hazard areas. This table may also
be used to evaluate the effect of "stacking," or the combina-
tion of several hazard zones on a single parcel of land,
which results in a high level of overall risk. As noted
in the preceding section, these policies should be reviewed
in conjunction with those contained in the Seismic Safety
Element.
TABLE 3
LAND -USE POLICY SUMMARY
LAND USE./FACILITY PIRE AND
FLOODING HAZARDS
I/E H M L
Nil 2/100F 3/DI
Critical
(e.g., Hospitals, fire
stations, police sta- 0 QX Q Q
Q OX
tions, and others as
shown on Table 1)
Noncritical
(e.g., Low -density resi-
dential, multifamily
residences, light 6A) ()] Q O
Q (2)Q/
industry, parks and
recreation areas,
agriculture)
Explanation
O generally suitable for development
0/ May be suitable for development with
site study and hazard
mitigation.
Generally unsuitable for development.
I/Fire hazard zones. 2/100-year flood area.
3/Areas of potential dam inundation.
Notes: This table is for general planning
purposes only.
Suitability for specific uses and sites must
be confirmed by
further investigations. If an area is evaluated
as generally
unsuitable for a particular use, that does
not necessarily
preclude the use if all potential hazards can be mitigated.
1.8
The most important implication of safety -oriented land -use
planning is that those buildings and activities wtich are
essential to the continued functioning of the city in the
aftermath of a major natural disaster be located in the
safest places. Other critical facilities should be located
only in those areas where design can ensure that they will
not become a major threat to life in the event of a flood
or fire.
These land -use policies, however, are not intended to pro-
vide a rigid definition of acceptable and unacceptable uses
for each hazard zone. The suitability of a specific use
for a specific site should be evaluated in the light of
current scientific information. if an area is evaluated
as generally unsuitable for a particular use, that does not
necessarily preclude the use if all hazards can be mitigated ill a
manner acceptable to the city. However, if such risks cannot be
adequately reduced, prohibiting the use is the only alternative.
D. Circulation Element
The basic circulation networks in the city and county are
tell established, and are recognized in the Regional Trans-
portation Plan and the city's and county's Circulation
elements.
The primary implication of the Safety Element for tte city's
Circulation Element is that a major flood can be expected to
block transportation routes within the city and to other cities.
This is expected to have an important impact on potential
evacuation and emergency -response efforts.
The Circulation Element is also related to the Safety H e-
ment with respect to fire hazards. Wildland fires are often
ignited at the roadside by burning ohiects tossed from
passing vehicles or 1iy accidents. Fire
hazards should be considered when future routes are selected.
Open Space Element
The Safety Element provides important information for the
Open Space Element by defining certain naturally hazardous
areas. Together with the earthquake hazard areas identi-
fied in the Seismic Safety Element, the fire am flood
hazards identified in the Safety Element suggest areas
for open -space uses. Specifically, these areas include
land within the 100-year floodplain, areas potentially
threatened by dam inundation, and areas of extreme or
high fire danger.
III. GOALS, POLICIES AND RECOI.04ENDED ACTION
A. Organization of'Planning Recommendations
The previous section of this Policy Report established
the general framework within which planning for public
safety should take place. It presented a summary of the
existing dangers to the city and a summary of how various
degrees of risk can be used as criteria in deciding how
to deal with hazards.
This section of the Policy Report is the heart of the city's
Safety Element. It establishes goals and policies and
recommends specific actions that should make the city
safer. (The specific planning actions are termed
''implementation measures.'')
The goals help us keep sight of the reasons for safety
planning. The policies point the directions the
city should take to meet the goals. The
implementation measures are the actions that
will carry out the policies.
While it would be desirable to fully implement
all of the policies, the city recognizes that money and
manpower are limited. In determining priorities for
allocating the community's resources, the city will con-
sider the expense required to implement the various
policies, the ease with which each could be acted upon,
and how important each policy is in achieving the Safety
Element's goals.
B. Goals
The city's goals in dealing with dangerous natural and
man -caused events are:
1. To minimize injury and loss of life.
2. To minimize damage to public and private property.
3. To minimize social and economic dislocations resulting
from injury, death and property damage.
C. Policies
The following general policies complement the planning goals
and definu specific directions for the city to take in
reducing risk:
1.0 Identify and evaluate existing structural hazards in
buildings used by the public and abate those hazards
to acceptable levels of risk.
2.0 Ensure that new development within the city's planning
area is designed to withstand the effects of natural
and man -caused hazards to acceptable levels of risk, and is dasigncd
to aid emergency response.
3.0 Control the use of land in areas of significant poten-
tial hazards.
4.0 Maintain and improve emergency -response planning and
organization.
5.0 Provide for more detailed scientific analysis of
natural and man -caused hazards.
6.0 Educate the public in the nature and extent of
hazards in the area and in ways of minimizing
the effects of disasters.
7.0 Review and improve the Safety Element on a regular
basis.
n
D. Implementation Measures
1.0 Identify and evaluate existing structural hazards in
buildings used by the public and abate those hazards
to acceptable levels of risk
1.1 Within the city, buildings which are used by the
public should be inspected by qualified structural
engineers, fire officials and flood control
officials for susceptibility to damage from fire,
flooding and geologic hazards. Inspections should
be conducted according to the following order of
priority:
1. Emergency -service facilities (e.g. fire and
police stations, hospitals).
2. Other critical facilities (e.g. schools,
government buildings).
3. High -occupancy buildings (e.g. theaters,
restaurants).
4. Other noncritical facilities (e.g. offices,
stores, high -density apartments).
Safety inspections should not be required for single-
family homes.
1.2 Caltrans should review its facilities and road-
ways within the city's planning area to determine
the potential impact of expected earthquakes
and floods, and should forward comments to the
city. Potential evacuation routes and the
Circulation Element of the general plan should
be revised if necessary.
1.3 The Southern Pacific Transportation Company
should review its lines and yards within the
study area to determine the potential impact
of the expected earthquakes. and should forward
comments to the city. The Circulation Clement
of the general plan should be revised if
necessary.
1.4 The Pacific Gas and Electric Company should review
its facilities and distribution/transformation net-
works and centers to determine the potential impact
of expected earthquakes, and should forward
comments to the city. PG&E should also review
its gas and power lines for potential fire hazards.
1.5 The city should encourage the inspection cf Righotti
Reservoir by qualified structural engineers to
determine its ability to withstand the ground -
shaking criteria presented in the Seismic Safety
Element.
1.6 If a structure has been identified as not conforming to earth-
quake standards or as a fire or food hazard, the risks it creates
should be brought down to acceptable levels. This might be done
by altering or rebuilding the structure or by other means. Where
flooding is the threat, risk could be reduced by improving
drainage rather than altering structures.
1.7 The city should begin condemnation proceedings in cases where
structures are earthquake or fire hazards.
(a) To implement this policy the Planning Commission shall rec-
ommend to the City Council criteria for determining what
constitutes a significant fire or seismic hazard. These
criteria should take into account the historic quality of
many of the city's older buildings.
(b) Appropriate city departments should begin condemnation
proceedings in individual cases.
1.8 The city should advocate the expansion of state and federal re- i
location -assistance funds and programs to aid persons and businessws --
displaced from hazardous buildings.
2.0 Ensure that new development within_ the_cily_'=)lanning
area is designed to withstand the effects of natural
and man -caused hazards to acceptable levels of riski
and is designed to aid emergency response
2.1 With the Seismic Safety Element and Safety Elvinont
as guidelines, the city's building regulations should
be reviewed and revised, if necessary, to incorporate
new minimum safety requirements regarding suisnd e
resistance, floodproufing and fireproofing, and to
address police and ifro department safety concerns.
2.2 All new construction in the city should, as a
minimum, meet the most recent safety require-
ments in the Building Code.
2.3 The city should review design standards set by the
zoning and subdivision regulations to make sure they
address the safety concerns of the police and
'fire departments. Prevention (including crime
prevention) and response should be among the
considerations addressed.
2.4 All new public facilities intended to reduce
risk from natural or man -caused hazards (e.g.
flood controlprojectsi firebreaks) should use
the planning and technical criteria presented
in the Safety Element as basic guidelines.
3.0 Control the use of land in areas of significant
potential hazards
3.1 New critical facilities (see Table 1) should be
generally excluded from the 100-year flood plain
and from areas of potential dam inundation. Non-
critical facilities should be allowed to locate
In potential flood areas only if the facilities
are elevated or floodproofed to the level of the
100-year flood and do not obstruct the free flow
of storm waters.
3.2 Development should be generally excluded from areas
of extreme and high wildland fire danger. Develop-
ment should not be permitted in areas of moderate
fire danger without an examination of its vulner-
ability to fire and its potential for starting one.
Wood -frame and other combustible structures and
untreated wood -shake roofs should be prohibited in
areas of extreme and high danger and carefully
evaluated in moderate -danger areas.
3.3 The use of off -road vehicles during periods of high fire
danger should be controlled. Rigid inspection standards
for off -road vehicles -- muffler and spark -arrester
controls at minimum -- should be established.
3.4 Land -use controls to reduce risk from seismic and
geologic hazards are described inthe city's
Seismic Safety Element. In summary, these
measures include the following:
(a) Prohibit construction in areas of high
landslide risk unless the slope stability
of the specific site is investigated.
(b) Prohibit critical facilities in areas of
very high liquefaction potential; regulate
noncritical facilities in these areas,
usually requiring site -specific analysis of
liquefaction potential.
4.0 Maintain and improve emergency -response planning and
organization
4.1 The city has prepared,and is responsible for
maintaining,an emergency plan as required by the
California Emergency Services Act. Among the
peacetime emergencies considered in the plan are
earthquakes, fires, and floods. The Seismic
Safety and Safety elements provide estimates of
the magnitude and location of these events and,
therefore, provide important information for the
emergency plan. The city's emergency -service
agencies should review their responsibilities and
capabilities in light of the information contained
in the two safety elements. Particular attention
should be given to the city's reliance on mutual
aid and the adequacy of communications
between different emergency agencies in the county.
1.12
5.3
After a significant number of site -specific soil
studies have been made in areas believed to have
very high potential for liquefaction, the city
4.2 The city Fire Department should work with county
should retain a qualified geologist to determine
and state agencies to improve mutual -aid arrange-
whether the potential for liquefaction does in
ments to achieve adequate fire protection in rural
fact exist.
areas around San Luis Obispo.
6.0 Educate the ublic in the nature and extent of
hazards in t e area and in ways of minimizing the effects
ofdisasters
4.3 The city should review its emergency plan to
6.1
The city should develop a program to familiarize
anticipate emergency services which may be
residents with the Safety Element. Special
required under mutual -aid agreements in the
attention should be given to those groups partic-
event of a radiological accident at the Diablo
ularly susceptible to seismic, fire and flood hazards,
Canyon Nuclear Power Generating Station. The
including, but not limited to, school districts,
city's emergency plan should also be revised to
agencies involved with the aged, and agencies involved
anticipate a radiological accident during the
with handicapped persons. These agencies should be
transportation of radioactive waste
from the Diablo Canyon plant. Primary emphasis
encouraged to develop their own education programs.
should be given to responding to an accident
The conclusions and recommendations of these
on the Southern Pacific rail line or on U.S.
elements should also be provided to land developers
101.
and those involved in the real estate profession.
5.0 Provide for more detailed scientific analysis of
6.2
Programs should be established tc train volunteers
natural and man -caused hazards
to assist police, fire and civil defense personnel
during and after a major earthquake, fire or flood.
5.1 The potential for landslide -generated water
6.3
Education programs should be initiated in lower
waves in Righetti Reservoir and their possible
grades, using displays and demonstrations that would
effects on the surrounding area should he
evaluated in detail.
expose younger children to the nature and strength of
fire. Such programs should tend to replace their
5.2 For future water impoundments, an evaluation of
natural curiosity with a sense of respect.
potential inundation areas should he
required and dams should be designed to with-
6.4
The city should support or sponsor exhibits and
stand the earthquakes which can be expected in
presentations in secondary schools which demonstrate
the area.
the more involved aspects of fire, such as major
factors contributing to fire hazard and the rela-
tionship of fire to the natural ecology. The city
also should encourage parents to help in 1he
overall fire -education program.
6.5 The city should enforce its ordinance requiring
smoke detectors in all residences.
7.0 Review and improve the Safety Element on a regular
basis
7.1 After the Safety Element is adopted, the Community
Development Department should see that the city
acts on the element's recommendations. The
department should keep the City Council posted
on progress.
7.2 The Safety Element should be revised comprehen-
sively every five years or whenever substantially
new scientific evidence becomes available.
TECHNICAL
PART 1 I:
TECHNICAL REPORT - TABLF 01: CONTF.N7:5
Page
Page
I. INTRODUCTION ................................
2.1
11. Nipomo...................................
2.52
II. FIRE HAZARDS ANALYSIS
G.
12. Oceano ...................................
Hazards From Dam Failure ......................
2.52
2.52
A.
General Statement .......................
2.2
H.
Relationships Between Local Planning and
B.
Contributing Factors to Fire Hazard .....
2.2
Federal Flood Insurance .......................
2.53
1. Wildland Fire Hazards ..............
2.2
2. Urban Fire Hazards .................
2.7
IV. GEOLOGIC HAZARDS ANALYSIS
C.
Existing Hazards & Response Capabilities.
2.11
A.
General Statement .............................
2.55
1. San Luis Obispo County .............
2.11
B.
Geologic Hazards ..............................
2.55
2. City of San Luis Obispo $ Vicinity..
2.20
1. San Luis Obispo County ...................
2.55
3. City of Morro Bay ..................
2.26
2. Cityof San Luis Obis Po
2.55
4. City of E1 Paso de Robles ..........
2.29
3. Morro Bay, South Bay, Cayucos and
S. City of Pismo Beach ...............
2.32
Vicinity .................................
2.57
6. City of Arroyo Grande ..............
2.35
4• Paso Robles, Atascadero and Vicinity .....
2.58
7. Grover City ........................
2.37
S. Pismo Beach, Arroyo Grande, Grover City,
A. Atascadero .......
2.39
Oceano and Vicinity ......................
2.59
9. South Bay ..........................
2.41
6. Cambria and Vicinity .....................
2.60
10. Cayucos, Cambria, Nipomo, Oceano ...
2.42
7. Nipomo and Vicinity ......................
2.61
C.
Effects on Utilities ..........................
2.61
III. FLOOD HAZARDS ANALYSIS
D.
Nuclear Reactor Facilities ....................
2.62
A.
Introduction ............................
2.45
E.
Dam Safety ........................ .........
2.62
B.
General Conditions ......................
2.45
C.
Climate .................................
2.45
V. RADIATION HAZARDS
D.
Streams .................................
2.46
A.
Purpose and Scope of Evaluation ...............
2.64
E.
Historic Floods .........................
2.47
B.
Radiation .....................................
2.64
F.
Existing Flood Hazards ..................
2.49
C.
Effects of Radiation ..........................
2.65
1. City of San Luis Obispo ............
2.50
D.
Nuclear Power Plants ..........................
2.65
2. City of Morro Bay ..................
2.51
E.
Nuclear Fuel Transport ........................
2.69
3. City of E1 Paso de Robles ..........
2.51
4. City of Pismo Beach ................
2.51
V1. EMERGENCY PREPAREDNESS
S. City of Arroyo Grande ..............
2.51
A.
General Statement .............................
2.69
6. Grover City ........................
2.51
B.
Emergency Response Organization ...............
2.69
7. Atascadero .........................
2.51
C.
Communications ................................
2.72
8. South Bay ..........................
2.51
1. Inventories ..............................
2.72
9. Cayucos ............................
2.51
2. Actions ..................................
2.75
10. Cambria .............................
2.52
D.
Medical Care ........
REFERENCES
.............................................
R-1
LIST OF FIGURES
LIST OF TABLES
Page
Page
1
Wildland Fire Hazard Fuel Potential ...............
2.3
1 Mutual Aide System .................. .........
2.70
2
Structural Fire Hazards Evaluation ................
2.8
2 Interjurisdictional Emergency Relationships...
2.72
3
Distribution of Cities Over 10,000 by
3 Leap Frog Concept ............................
2.77
Total Fire Insurance Classification and
Classification of Fire Department .................
2.12
LIST OF MAPS
4
Historic Wildland Fires........... ....... .........
2.13
S
Existing Rural Structural Fire Protection
(Available through local Planning Agency)
Facilities, San Luis Obispo County ................
2.17
6
Proposed Fire -Fighting Facilities, San
Fire Hazards, San Luis Obispo County
Luis Obispo County ................................
2.19
Urban Fire Hazards, City of San Luis Obispo
7
Fire Incidence, City of San Luis Obispo ...........
2.23
Natural Hazards, City of San Luis Obispo
8
Fire Protective Resources, Cayucos, Cambria,
Natural Hazards, City of El Paso de Robles
Oceano, Nipomo........................................
2.45
Natural Hazards,, City of Morro Bay
9
Mean Seasonal Precipitation .......................
2.46
Natural Hazards, City of Arroyo Grande
10
Flood Damage Summary, 1969, San Luis Obispo
Natural Hazards, City of Pismo Beach
County .............................................
2.41
Natural Hazards, Grover City
11
Elevation Dates for 100-Year Flood Along
Natural Hazards, Atascadero
San Luis Obispo Creek and Tributaries .............
2.50
Natural Hazards, Oceano
12
San Luis Obispo County Emergency Medical
Natural Hazards, Nipomo
Facilities ........................................
2.78
Natural Hazards, South Bay
Natural Hazards, Cambria
Natural Hazards, Cayucos
ii
I. INTRODUCTION
This Technical Report for the City of San Luis Obispo
Safety Element is the Technical Report from the Regional
Safety Element prepared in 1975 for the San Luis Obispo
County and Cities Area Planning Coordinating Council,
with the exception that pp. 2.20 and 2.21 concerning
fire hazards in the City of San Luis Obispo were updated
In April 1978.
The purpose of this part of the Safety Element is to
provide the necessary technical back-up for the recommen-
dations contained in the Policy Report. To that end,
this part analyzes a series of major potential hazards
to life and property. Since it was part of the Regional
Safety Elelent, it analyzes hazards throughout the county.
Primary emphasis of the report is on analysis of wildland
and urban fire hazards, natural flooding and dam inundation.
The report also presents a discussion of potential radiation
hazards and emergency preparedness within the county.
The technical nature of some of the information contained
in this report necessitates a scientific dicussion. How-
ever, because of the diverse audience for the Safety Element,
the approach has been to minimize the use of detailed dis-
cussions whenever possible and to rely on qualitative de-
scriptions of methodology and safety hazards. Those wishing -
a more detailed discussion of public safety hazards are
referred to the works listed in the References section.
2.1
II. FIRE HAZARDS ANALYSIS
B. Contributing Factors to Fire Hazard
A. General Statement 1. Wildland Fire Hazards
The major emphasis in this portion of the investi-
gation is the analysis and evaluation of fire hazards
originating in both the developed and undeveloped
areas in the County of San Luis Obispo. Fires occurring
in developed areas are most often structural fires,
automobile fires, and small to medium-sized brush
fires. Fires in undeveloped areas include large
brush and forest fires that commonly engulf tracts
of land several hundred to many thousands of acres in
size.
The Fire Hazards portion of the study is organized to
reflect the inherent differences between urban fire
and non -urban fire. Section B1 will discuss the
various aspects of fire in the undeveloped portion of
the County, including the factors which create fire
hazards, and Section B2 will focus upon the causes of
urban fires. Section C examines the level of fire
hazards and response capability in both developed
and undeveloped areas of the County.
Losses through fire have climbed at a steady pace
since World War 11, reflecting the increase in dollar
values through inflation and economic growth. The cost
in terms of human life has also increased such that
over 12,000 deaths and 2,000,000 non -fatal burns occur
each year throughout the nation. These continued losses,
which are occurring despite rapidly improving fire -fighting
techniques, demonstrate the need for more efficient
fire prevention. Land use planning as ❑ means of reducing
fire hazards is one means through which more effective
prevention can be attained.
2.2
a. General
Fires in undeveloped areas that result from the ignition
of accumulated brush and woody material are termed
"wildland fires, and represent a major threat to,
safety throughout the State. In recent years, large
wildland fires have plagued much of California, destroying
structures and exacting a heavy toll on life and valuable
watershed acreages. During a 13-day period in 1970,
wildfires throughout the state destroyed over 580,000
acres of wildland, consumed 722 homes, and damaged
thousands of other structures. Sixteen lives were lost
and property damage soared to 233 million dollars.
The basic wildland fire problem confronting California
is that wildland fire is a natural element of the
regional environment'. Therefore, despite the State's
having the best financed and most effective wildland
fire protection organization in the world, the problem
persists. The three environmental factors most respon-
sible are climate, vegetative cover, and topography.
Another factor which has exacerbated the problem is man's
presence in fire prone areas, a condition that is
increasing'as more and more human activity is intro-
duced through residential development and recreational
activities.
b. Natural Factors
(1) Climate
California's climate is Mediterranean with cool moist
winters followed by long, dry summers. Rainfall deC1'CaSes
sharply with a drop in elevation from the mountains
to the lower foothills and valleys. The long
summers with little or no precipitation are often
accompanied by relatively high temperatures and
low humidity away from the immediate coastline. The
long rain -free periods, warm air temperatures, and
high humidity draw moisture out of large accumula-
tions of dead fuel and place living vegetation under
increased moisture stress.
The position of San Luis Obispo County relative
to the Pacific Ocean and the Coast Range helps to
modify climatic extremes, producing a diversity of
climatic regimes throughout the County. At its
widest point (measured diagonally), the County is
over 120 miles long. Along that line, climatic
conditions vary from the cool, damp north coast to
the hot and dry Cuyama Valley. Cool winds from the
Pacific and frequent fogs help maintain moisture
levels in the local vegetation along the coast to
retard fire. However, the climatic conditions of
the Santa Lucia Mountains and the inland plains and
valleys create very dry conditions, conducive to
wildland fire.
(2) Vegetative Fuel Potential
The second natural factor contributing to the overall
hazard of fire is the type of vegetative cover.
Vegetation is closely related to the type of climate
of an area. Many species of plants respond to
available moisture as the most limiting environmental
factor. In areas where moisture is more or less im
constant supply through rainfall, stream runoff or
persistent fogs, dense evergreen forests become
established. However, in drier areas where rainfall
is more restricted and fogs are only a minor environ-
mental element, vegetative types adaptable to low
moisture conditions develop and flourish. Among
these dry -adapted species are the common chaparral
2.3
and interior grassland elements including chemise
(Adenostoma fasciculatum), various Ceanothus species,
and grasses o many varieties.
The type of vegetation present, along with its density
and distribution, can define both the overall hazard
of fire in a particular area and the intensity of fire
which ensues. These characteristics of the local
vegetation can also determine the fire's spreading
potential, and can decide the recurrence intervals
to be anticipated between outbreaks of fire. San
Luis Obispo County contains 14 naturally -occurring plant
communities, a reflection of the County's diverse
environmental profile. The following table lists
the various communities, as well as their fire hazard
potential.
Table 1
Wildland Fire Hazard Fuel Potential
Extreme High Medium Low Nil
Chaparral North Coastal Riparian Wood-. Beach -dune Coastal
Scrub land Salt Marsh
Foothill
Woodland
Juniper Oak
Woodland
North Coastal
Grassland
Evergreen
Forest
Interior
Herbaceous
Desert
Scrub
Coastal
Sand -plains Freshwater
Saline Marsh
Plains
Chaparral is a general term that describes a great variety
of closely -crowded evergreen shrubs. Stands of chaparral
can differ widely in species from place -to -place, however,
chemise (Adenostoma fasciculation) is its most cunstunt
member. -- — — ---
Ceanothus cuneatus is probably second in abundance,
with other species of Ceanothus being more abundant
in certain localities Hoover, 1970). Species of
manzanita (Arctos�ta h loss) are also common members
of the chaparral community in San Luis Obispo County
as are several scrub species of oak ( uercus dumosa,
Q. durata, Q. Wislizenii var, frutescens, etc.).
Chaparral is most commonly found on t e drier, sun -
exposed slopes of hills, mostly inland, extending to
La Panza Range.
Chaparral, especially chemise-dominatedstands,
are the most fire hazardous plant community encountered
in. the area. Chemise contains a large percentage of
volatile oils within its tissues that can ignite and
burn with a great deal of vigor. A name once applied
to chamise was "grease wood!', a term that aptly
characterizes fires in overgrown chamise areas.
Chaparral communities have not only adapted to a dry
environment, but have come to virtually depend on fire
as a necessary element in the environment. Several
component species of the chaparral community require
the scorching heat of fire for seedling germination,•
while others have developed the capacity to re -sprout
from existing root stocks. This capability allows a
burned community to rapidly re-establish itself such
that in the span of four to five years, re -vegetation
will be approximately 70% complete.
Three communities, North Coastal Scrub, Foothill Wood-
land, and the .Juniper Oak Woodland, compose a "high"
fire risk potential. North Coastal Scrub is best
represented from Cambria northward, and is characterized
by the presence of species of Ceanothus, Mulefat
(Baccharis pilularis) manzanita (Arctosyaphylos spp.)
and California Sage (Artemisia californica). As the
term "scrub" implies, this community is fairly low,
and shrublike in nature. It presents a high degree
2.4
of flammability due to the volatility of the plant
tissues, however, the lack of overall density, and the
absence of chemise makes it a lesser threat than
chaparral.
Foothill Woodland can be found from the east base of the
Santa Lucia Range across the upper Salinas Valley to the
hills bordering La Panza Range on both sides. Foothill
Woodland can also be found in the upper Arroyo Grande
Valley as well as Cuyama Canyon (Hoover, 1970). It is
dominated by species of drought resistant trees including
Digger Pine (Pinus Sabiniana), Blue Oak ( uercus Douglassii),
Valley Oak ( uercus lobata), and Live Oak ( uercus agrifolia).
Foothill woodlands often exist together with certain
chaparral elements that further compound the fire problems
that exist. The overall moisture stress in the dry
environment of the Fooh_il•l Woodland also contributes to
the hazard potential.
Juniper -Oak Woodland characterizes the vegetation around
the north end of La Panza Range, southward along the San
Juan River, and in the higher regions of the Temblor
Range. The high fire hazard of California ,Juniper
(Juniperus californica) - Blue Oak (Quercus Dou lassii)
plant community results from its adaptation to ry con-
ditions as well as the understory growths of grasses
and shrubs that could readily burn if ignited.
The five plant communities whose presence generally
indicates a medium fire hazard include: Riparian Wood-
land, Evergreen Forest, Interior Herbaceous, and Desert
Scrub. One of two characteristics apply to each of
these communities, and explain their medium fire hazard
status. Each community listed either (1) maintains a
sufficiently high moisture content to partially mitigate
fire hazard buildup, or (2) possesses such an open
and/or sparse density profile, that the chances of a
wildland fire igniting and consuming widespread acreages
are less likely.
Riparian woodlands are usually composed of broad-
leaved trees that thrive under the
differences and local climates (Hoover, 1970). However,
moist conditions
found in and along creek bottoms. Representative
the grazing activities of livestock as well as the low
species include California Sycamore (Platanus racemosa),
growing herbaceous nature of the vegetation renders
such areas a medium fire hazard instead of a "high
Cottonwood (Po ulus Fremontii), and Bigleaf Maple
(Ater macrophyla The igh moisture
hazard" as encountered in North Coastal Grassland areas.
content of the
leaves and woody tissues along with the usually
The Desert Scrub plant community is best represented
permanent supply of water helps mitigate the hazard
fire in
in the Temblor Range, especially southward to the
of this plant community.
South slope of Caliente Mountain (Hoover, 1970). Its
The Northcoastal Grassland Plant Community can be
found
representative species include Desert Tea (E hp edra
california), Saltbush (Atriplex polycarpa), and Buck -
in scattered locations throughout the County,
however, it is best
wheat (Eriogonum fasciculatum var. polifolium). The
represented on the open hills and
ocean bluffs from Cambria northward. In many
Desert Scrub community is generally a community quite
portions
of its range, the community has been disturbed
open and sparse, a factor which mitigates the community's
fire
through grazing and other farming activities. The
potential despite its dry character.
hazard potential of the Northcoastal Grassland community
is decreased due
The five remaining plant communities in the San Luis
to the cool and moist climatic
regimes of areas in which it is found.
Obispo County area comprise the "low" and "nil" wildland
fire hazard fuel potential categories identified in
The F.vergeen Forest community, much like the Riparian
Table 'Low" hazard categories include the following:
Woodland, is found in areas where moisture is more
plentiful. Greater rainfall
(1) The Beach -Dune community found from Pismo
amounts, and persis-
tent fogs help maintain the amount of water, and create
Beach to the mouth of the Santa Maria River,
the necessary conditions for the various species of
and along the west side of Morro Bay.
the community. These species include several pine
(2) Coastal Sand -plains and stabilized dunes,
species, Live Oak ( uercus agrifolia), Canyon Oak
located inland from the Beach -Dune Community,
( uercus chrysolepis), California Laurel (Umbellularia
including the South side of Morro Bay and the
california) and Madrone (Arbutus menziesii). Ever-
Nipomo Mesa (Hoover, 1970).
green Forest usually occurs in rather small areas
near the coast and in the Santa Lucia Range (Hoover,
(3) Salina Plains, located in the Cholome Valley;
1970).
Carrizo Plain around Soda Lake; south to
Cuyama Valley.
"Interior Herbaceous" is a plant community exten-
sively found in the
Each of these three communities includes a fairly sparse,
eastern portion of the County.
It is comprised of many herbaceous and
low -growing flora, the structure of which minimizes
grassy species
that have flourished in rangeland areas, disturbed
their overall fuel potential.
by livestock grazing. Areas of interior Herbaceous
vary significantly from one another, because
The "nil" categories include vegetative categories directly
of soil
linked to the presence of standing water, and they include
2.5
the Coastal Salt Marsh and Freshwater Marsh communities.
The aquatic nature of these plant communities pre -
clue the potentiality of wildland fire.
(3) Topography
The third major natural factor influencing wildland
fire hazards is the topography of the area. Topography
has considerable effect on wildland fire behavior
and the ability of fire fighters and their equipment
to take suppressive action on those fires.
San Luis Obispo County lies astride the Santa
Lucia Mountains, a major portion of the Coastal Range
of California. The Santa Lucias rise to altitudes
greater than 3500 feet and form a mostly continuous
tract of rugged terrain with numerous canyons and
ridges of slopes approaching 100%. The presence of
the Santa Lucia's in the western portion of the County
has contributed significantly to the levels of
wildland fire hazards.
The rough topography of the Santa Lucias greatly
limits road construction and road standards, and
accessibility by ground equipment. The California
Division of Forestry has classified slopes relative
to fire prevention on the following basis:
% Slope
Class 1 0-40
Class 11 41-60
Class 111 61{
Slope Class I fires can be attacked with all -wheel -
drive equipment, bulldozers, hand crews, and air-
craft. Slope Class 11 fires are beyond the operating
capability of alI-wheel -drive equipment, but can he
attacked using bulldozers, handcrews and aircraft.
Slope Class III fires can be effectively combatted
only through the use of handcrews and :aircraft.
Using the Division of Forestry criteria, most slopes
in the Santa Lucia Mountains are Class 161. Class 1
and II slopes occur to the east of the range. The Irish
Hills, an isolated mountainous area south of Morro Bay
also contains slopes of Class I and Class 11 stature.
Steep topography can also have a major effect oil the
behavior of fire. Canyons and ridgelines tend to channel
air flows, creating extremely erratic winds on Ice slopes
in an area. Fires also demonstrate a tendency to
rapidly spread in an upslope direction , disc to the super
heating which occurs above a fire within the confines
of a canyon.
c. Human Factors
The principal human factor important in the analysis of
wildland fire is the presence of people in the wildland,.
Recent statistics compiled by the State Division of
Forestry indicate that over two-thirds (2/3) of all
wildland fires are caused by human activities in one
form or another. The following list describes the
types of man -caused fires and their relative purceutagc
of occurrence:
Fower line facilities 23'.
Incendiary or arson 220
Machine use 16.
Debris burning 6.19.
Total 67.1.
Source: California Division o1'
Forestry, 1972
Despite the type and amount of fuel present, topography.
or weather conditions, a wildland fire requires all
ignition source, and according to available n•cord:;
people furnish that source o7.1% of the time. Fur that
reason, wildland areas exposed to human nrtiritUS,
either tlu•ough w•bani=ation, back country rccrcatioo,
C
power line easements, or circulation via back
country roads, might warrant a more severe fire
hazard classification.
2. Urban Fire Hazards
a. General
Fire has long been recognized as an especially dan-
gerous threat in urban areas. As the population
concentrates in increasingly built-up areas, the
factors necessary for fire ignition increase as
do the chances of a fire spreading rapidly once
it starts. These same factors of population, material,
and energy concentrations in cities mean that loss
of life, injury, and property damage from fire are
greater in urban areas. The historic great fires in
Chicago and San Francisco near the turn of the century
are well known.
Two primary concepts govern the potential for loss
from urban fires: fire prevention and fire response.
Each of these concepts involve a number of contri-
buting factors which can be thought of as assets
and liabilities to fire hazard reduction. These fac-
tors are discussed in general in the following para-
graphs and Section 2c evaluates the specific condi-
tions in the urban areas of San Luis Obispo County.
b. Structural Types and Fuel Potential
It is difficult to judge which factor is the most
important in determining the overall level of risk
from fire in an urban area because any one factor can
make a critical difference. However, both fire pre-
vention and response are largely a function of what
there is to.burn within an urban area. Some sections
of an urban area may pose unusually high fire risks
where the chances of ignition are high and the ability
to respond is low. Other areas may not have any parti-
cularly serious problems. Within most urban areas,
the most serious fire problem involves residences
2.7
and other types of buildings. Each year in cities there
are also a number of rubbish and grass fires, vehicles
fires, and aircraft and ship fires at airports and harbors.
The primary concern in the urban areas of San Luis Obispo
County, however, is with structure fires.
Structure fire problems are basically a function of the
type of construction and the type or use of the facility.
Construction types in most.cities may be thought of as four
kinds with respect to fire hazard: fire resistive, non-
combustible, ordinary, and wood frame. Fire resistive
construction encompasses a broad range of construction
types and is generally defined as construction to resist
the spread of fire. This means incorporating such measures
as fire blocks in the walls, treated shingle roofing
tiles, treated paneling, and automatic sprinkler systems.
Fire resistive requirements do not allow any material
other than "resistive" or "protected". Details of the
fire resistive construction are spelled out in the local
fire codes. Non-combustible construction is limited
to all metal buildings. Ordinary construction includes
brick construction which is typified by masonry walls,
jointed floors, interior partitions and roof structures
of wood, and heavy timber construction. Frame buildings
are wood construction throughout, and pose the greatest fire
hazard.
The type of structure is of central importance in deter-
mining both preventive measures and response strategies.
What a structure is used for is a main factor in deter-
mining the overall size of the building, its layout,
occupancy levels, flammibility of contents, its private
protection facilities, and overall hazards to life. ']'able
2 presents a summary evaluation of the fire hazards of
various types of facilities. This table is generalized and
should not be construed ;IS a Suuun:u.y of haz:u•ds i❑ San
Luis Obispo County. Rather, it lists potential hazards.
Of special concern to public safety are the following types
of facilities: residential buildings, multi -story buildings,
hospitals and medical facilities, indoor public assembly
facilities, and industrial facilities. Each is discussed
1
TABLE 2
STRUCTURAL. FIRE HAZARDS EVALUATION
'TYPE OF BUILDINGS
CONTENTS
LIFE
SPECIAL. PROBLEMS
Government
Low
Considerable
Open wells and concealed spaces accelerate spread
of fire. Locked doors in 'ails.
Institutional
Low
Severe
Locked doors, exits in assembly rooms, frequently
insufficient water supply.
Amusement
Low
High (when crowded)
Flimsy construction,quick-burning materials.
Single and
Low
Considerable
Buildings close together, wood single roofs.
multiple dwellings
Combustible rubbish. High frequency of fires in
low-grade hotels and rooming houses.
Office
Low
Low
Small office buildings of combustible material.
Department Stores
Moderate
high (during peak
_
In small stores, congested stock, often
shoppingperiods)
lacking sprinklers.
Wholesale mercantiles,.
High
Low
Stock pi -led too high for sprinkler control.
single occupancy
Shopping Centers
High
Possible
Lack of openings. Congestion, long lays from
public hydrants.
Railroad and wharf
Moderate
Low
_
Access obstructed by railroad cars and tracks, —
property
wharves accessible from one end only, underdecks
wholly inaccessible. Many buildings not s rinklered.
Lumber yards
High
Low
Flying brands, concentration of large amounts of
burnable material.
Bulk oil storage
High
Possible
Supplies of foam needed for large plants.
Garages B Filling Stations
Low
Low
_
Unprotected steel roof trusses .and wood roofs
subject to collapse in fire.
Industrial
Varies with
Low
Special process hazards.
character of
material mfg, and
process employed
Taken from: Municipal F ire Administration,
International CPty anagel� rs Association, 67.
2.a
o C) 0
in general terms in the following paragraphs.
Those mentally or physically debilitated cannot react
It should be remembered that the following represents
during crisis in a way that would ensure minimum
safety hazards. In times of emergency,
a summary of potential hazards. Local fire and build-
ailments are
ing codes in San Luis Obispo County recognize and
aggravated by stress, and the medical staff is usually
prohibit many of these hazards.
inadequate to provide enough aid and guidance.
(1) Residential Buildings
(4) Indoor Public Assembly Facilities
Single-family detached houses form the major portion
Public assembly facilities are defined as those in which
of the housing stock in San Luis Obispo County.
large numbers of people congregate in generally unfamiliar
Fires occur more frequently in private homes from
surroundings. They include schools, theaters, churches,
a variety of causes, with human carelessness chief
temples, and a variety of recreational facilities.
There
among them, and more lives are lost in residential fire,
are a number of these buildings ill the study area
than in any other type of fire. One particularly
including several schools. Gatherings of' large numbers
dangerous hazard in residential fires is the use of
of people in these buildings create conditions conducive
untreated wood shingles in roof construction. Windy
to mass panic in a crisis, which only worsens and increases
conditions could spread the fire to a large number -of
the casualties. Administering medical aid is made more
other houses where this type of roof is common.
difficult in these situations as well.
Perhaps the most dangerous type of residential building
(5) Industrial Fire Ilazards
is the low-grade hotel or rooming house. These
buildings are characterized by open stair wells, sub-
Potentially hazardous industrial operations encountered
standard electrical wiring, and often faulty heating
in the study :area include utility lines such as gas
systems. Upon ignition, fires in this type building
lines :and overhead electrical power lines. While the
spread rapidly throughout the structure minimizing
normal construction of utility lines provides a high
degree of safety, lines break
the opportunities to escape.
gas cull and power lines
can come down and result in fires. They should not he
(2) Multi -Story Buildings
overlooked as fire hazards.
Buildings over 5 stories pose difficult fire control
C. Dire Prevention
problems. The large number of occupants and their
In addition to the available stock of combustible material
dependence on internal support systems such as water
in a city, fire prevention focuses on the location and
pressure systems, ventilation systems, and elevator
arrangement of fire hazardous land uses, public awareness
systems increase the potential for disaster. Adequate
of fire hazards, and the available .lata base regarding
response to high-rise fires requires special equipment
hazards. Considering the location of land usos with
such as helicopters and aerial ladders.
respect to fire hazard caul he an important preventive
measure. In areas of high wildland fire risk, it may be
(3) Hospitals and Medical Facilities
considered unacceptable to build eertain types of
facilities unless nu•asures ;i e required at the site to
These facilities present critical fire control problems.
mitigate the risk. tin tau, high density development
Damage to sophisticated medical equipment by fire
may be Considered unacceptable from the vivwpoinl of fire
threatens the lives of present and future patients.
Ira-ards because fires have greater nppnrtLill ity to spreaJ
..9
I*
rapidly, and cause more damage in higher density develop-
ments. These are planning considerations and should
not be construed as rules of fire prevention. Mitigation
measures are available that will offset the fire hazard
that exists in high density areas. In addition, fire
is only one factor that should be considered in the
planning process, and mitigation measures at the site
design level can make high density or location near high
risk brush fire areas acceptable. However, location
and density are major factors governing urban fire hazards.
As with all preventative measures, it is hard to measure
the effectiveness of public awareness of fire hazard as
a deterent to fire starts. It is known, though, that
human carelessness is the greatest cause of urban fires.
Public knowledge of the causes of fire, especially in
their own homes or businesses, is the starting point for
reducing hazard. Its value cannot be underestimated.
In the same way, an adequate technical data base of fire
hazards in an area is an invaluable tool to the professional
fire -fighting organization. Detailed knowledge of the
location and type of potential fire problems in a juris-
diction is the necessary basis for implementing preven-
tive measures and planning response strategies.
d. Fire Response
The traditional mission of fire -fighting administrations
includes both fire prevention and response once a fire
starts. Responde strategies have three major objectives:
(1) prevent loss of life and property when a fire starts,
(2) confine the fire to its origin, and (3) put out the
fire. The principal factors contributing to successful
fire response involve both the urban planning process
and the application of fire control technology.
Adequate fire response means getting sufficient equipment
and manpower to a fire quickly enough to reverse the
course of the fire. Response time is usually measured
from the time of alarm to the time fire -fighting units
arrive at the scene. It is a critical factor in minimizing
fire loss, and is a function of the time it takes to
2.10
detect a fire, the number and locations of fire sta-
tions, the access routes to the fire, and the .quality
of street numbering systems. Of highest importance to
saviang lives is the early detection of fire, especially
in residences. Installation of smoke detectors in
private residences is an effective means of early
detection. All of these factors are important considera-
tions to include in the planning process.
Another major factor in fire response is the available
flow of water to surrpess the fire. The term fire flow
refers to the delivery rates of water that should be
maintained to adequately halt and reverse the spread
of fire. Optimum fire flow requirements range from a
minimum of about 500 gallons per'minute (for 2 hours) to
about 5000 gallons per minute (for 5 hours) depending on
the type of land use. Single -story residential building
fires can be contained and extinguished with a SOO gpm
fire flow, but high rise construction or large commer-
cial developments necessitate the higher fire flows of
about 5000 gpm. In some of the more recent single-family
residential construction, 500 gpm is considered too low
for 1000 gpm is becoming a more realistic minimum figure.
The type of land use or facility is also a major determi-
nant of the number and quality of personnel, and type of
equipment needed to adequately combat fires. For example,
high rise structure fires often require the use of aerial
ladders, snorkels, and helicopters to deliver the fire
retardant. Of course, it is necessary to have trained
personnel to operate these more sophisticated types of
equipment as well.
As with fire prevention, public awareness plays an
important role in fire response. How an individual or
group reacts to a fire can mean the difference between
efficient evacuation or panic. The value of fire drills
cannot be underestimated in assuring safety in the event
of it major fire. lit addition, it populace that knows to
avoid the scene of a major fire, and that does not hinder
the work .of professional crews provides significant help
in controlling fires.
1V*
e. City Classification
of risk along the southcoast portions of the County
One of the more important implications of maintaining
to extreme hazards in the mountain chaparral stands
adequate fire prevention and response abilities is the
of the Santa Lucia Mountains. As discussed in the
effect of fire pootection on the premiums charged for
previous section, wildland fire hazards result from
fire insurance. Within certain limits, the better a
the interaction of several factors, both natural
city provides for fire protection, the lower the cost
and man-made. The Wildland Fire Hazards Map for
of fire insurance. Of course, many factors, such as the
San Luis Obispo County displays the relative hazard
type of building and construction, contribute to deter-
zones, and is a result of the synthesis of the major
mining the cost of insurance, but the strength of a
factors discussed in the preceeding section of the
city's fire defenses is one of the most important fac-
report.
tors.
The major fire problems within the County occur in
The level of protection provided by the fire department
the Santa Lucia Mountains, and the Irish Hills area.
in a jurisdiction is determined by the Insurance
These areas exhibit the combination of vegetative
Services Office's (ISO) Standard Grading Schedule.
fuel type, topography and human proximity that
Cities are classified according to the relative value of
result in extreme hazards. The two "most" signi-
fire defenses into one of 10 grades, from Class 1
ficant fire prone locations are, 1) areas west of
to Class 10. A Class 10 community would be one without
Santa Margarita where, through the years, numerous
a fire department or water supply meeting fire flow
fires 50-500 acres in size have occurred; and 2) an
requirements while a Class 1 community is one judged
area west of Nipomo, where numerous fires.50-300
most able to cope with fire. As a community improves
acres in size have occurred. Another fire prone
its fire defenses, its Class improves, and fire insurance
area adjoins Nacimiento Reservoir to the southwest.
premiums on property in the City are lowered. Table 3
There, .in 1960, the largest wildland fire in the
shows the distribution of cities in the U.S. according
recorded history of San Luis Obispo County occurred,
to their fire insurance classifications. Table 3
consuming over 80,000 acres.
shows that the majority of cities with populations between
10,000 and 25,000 are in Classes 4, 5, 6, and 7, and the
Fires, of course, are capable of occurring in :any
majority of those over 25,000 are in Classes 3, 4, 5,
fire risk level, however, they are more likely to
and 6. The Table does not show data on cities under
occur in the "high" and "extreme" risk areas.
10,000, but Municipal Yearbook data indicate that the
Table 4 compiled from Division of Forestry records
great majority of municipalities under 10,000 are in
of all major fires occurring outside of Los Padres
Classes 7 and 8.
National Forest, lists the extent of each fire in
approximate acres, the general location of each
C. Existing Hazards and Response Capabilities
burn, and the relative hazard level of each burn
area (based on the findings of this analysis).
1. San Luis Obispo County
a. Wildland Fire Risk
San Luis Obispo County is exposed to a variety of wild -
land fire hazard conditions ranging from very low levels
2.14
TABLE 3
DISTRIBUTION OF CITIES OVER 10,000 BY TOTAL FIRE INSURANCE
CLASSIFICATION AND CLASSIFICATION OF FIRE DEPARTMENT
Total Fire Insurance Classification
All
Cities
over 25,000
Total
Classification of
Class--
Fire Department
2
Fire
Number
Percent
Cities
250,000
100,000
50,000
25,000
Cities
Cities
Cities
Insurance
in each
in each
over
to
to
to
to
10,000
over
10,000
Class
Class
Class
50,000
500,000
250,000
100,000
50,000
to 25,000
25,000
.4
to 25,000
1
0
0.0
0
0
0
0
0
0
7
0
2
18
2.7
10
4
1
3
0
0
38
8
3
161
24.2
10
21
38
S6
36
20
108
21
4
189
28.4
1
0
29
53
106
113
139
57
5
172
25.8
0
0
7
44
121
253
12S
129
6
106
15.9
0
0
1
is
90
333
111
226
7
19
2.9
0
0
0
3
16
128
91
223
8
1
.1
0
0
0
0
1
28
23
132
9
0
0.0
0
0
0
0
0
1
3
39
10
0
0.0
0
0
0
0
0
0
2
18
Reporting
666
100.0
21
25
76
174
370
876
647
8S3
Source: The Municipal Year Book, 1966
1Where a city is given more than one grading, it is entered at the lowest total class.
2
The fire rating bureaus for Wyoming, New Mexico, and Colorado do not issue fire department
classification ratings as such; however, fire department deficiency points are included in the total rating.
2.12
TABLE 4
HISTORIC WILDLAND FIRES
Date of
Occurrence
Location
Acreage
(approx.)
Fire Risk
Zone
Date of
Occurrence
Acreage
Fire Risk
Location
(Approx.)
Zone
1931
Frog Pond Mountain
700 acres
Extreme
1947
Dover Canyon
600 acres
1931
Portola Road (Atas-
cadero)--Santa Rita
28,000 acres
Extreme
1947
Cuyama Highway
10,000 acres
Extreme
High
one fatality
Taylerlyn Fire
1933
Rinconada Area
15,000 acres
High
1949
Steelbridge Fire-
4,000 acres
Extreme
1937
North of Cambria
Hearst Ranch
10,000 acres
Extreme
1950
pozo
Pine Ridge Huasna
17,000 acres
Extreme
July
to USFS
1938
Paradise Valley
750 acres
Extreme
1950
Pilatas--to
33,000 acres
1938
Bailey
250 acres
Extreme
Creston No struc-
Extreme
1939
Cerro Alto --Cathleen
Valley
15,000 acres
Extreme
ture loss--4
fatalities, 1
Eagle Ranch,
Santa Margarita
CDF, 3 N.G.
Ranch
19SO
Hillman Ranch--
10,000 acres
High
1939
American Canyon
30,000 acres
Extreme
East of Paso
Robles
1939
Freeborn Mountain
4,000 acres
High
1951
Black Mountain
1940
Las Politas
7,000 acres
Extreme
Navajo fire Pozo
(jumped road,
grade
river)
1942
Behr--Huasna area
400
1951
Nacimiento Lake--
3,000-4,000 acres
High
acres
High
Godfrey
1942
Tri-County Fire,
1,400 acres
High
1952
Bonheim Ranch
1,000 acres
Extreme
NE County--SI.O,
Kings, Kern
1952
Blue Goat Fire--
500 acres
ExtremeSouth
1942
SLO/proximity of
700
of Creston
City Coon Creek
acres
Extreme
1952
Pink Goat Fire
3011 acres
Extreme
1942
Vasquez boat
Extreme
1952
Caliente Mountain-
4,000 acres
High
east side
2.13
0_1
TABLE 4
(con It.)
Date of
Acreage
Fire Risk
Date of
Acreage
Fire Risk
Occurrence
Location
(approx.)
Zone
Occurrence
Location
(approx.)
Zone
1953
Buckhorn Ranch
13,500 acres
Extreme
1972
Nipomo Mesa and
300 acres
high
(burned into USFS)
Eucalyptus Fires
1953
Sam Jones --Monterey
300+ acres
High
1972
Donati
700 acres
High
County burned into
in SLO only
1972
See Canyon
400-500 acres
High
SLO County
1953
Los Berros Canyon--
7,000 acres
High -Low
1973
Santa Margarita--
3,500 acres
Extreme
Delasi fire
Calf Canyon
1953
Ocean View fire
600-700 acres
Extreme
1973
Tri-County Fire
3,000 acres
High
July
1955
Bee Rock
4,000 acres
High
1955
Iron Springs-
2,000 acres
Extreme
Source:
California Divison
of Forestry, 1975.
Huero Creek
1957
Nacimiento
700 acres
Extreme
1959
Creston --Union
400 acres
Extreme
School
1960
Wefferling--SLO
80,000 acres
Extreme
acres
1970
Shell Creek
20,000 acres
High
1970
Buckeye --from
500-600 CDF
Extreme
October
USFS to CDF
44,000 acres
on USFS
1970
Alfafa Ranch Fires
20,000 acres
High
1970
Santa Margarita
4,000-5,000
Extreme
acres
1970
Pilatas
1,000 acres
Extreme
1971
Parkhill fire
2,700 acres
Extreme
2.14
r
Other major fires have occurred within Los Padres
National Forest, an area located entirely within
the "High" and "Extreme" hazard levels.
Responsibilities for the prevention and abatement of
wildland fires belong to the U.S. Forest Service
(USFS) in areas contained within Los Padres National
Forest, and to the California Division of Forestry
(CDF) in wildland areas outside of the forest boundaries
Both of these agencies maintain numerous stations
throughout their jurisdictions, each equipped with wild -
land -oriented fire equipment, and trained personnel.
Because of its responsibilities and its large area of
jurisdiction, the California Division of Forestry
stands as the major fire fighting force in San Luis
Obispo County. The Division maintains 13 fire stations
in, or near the communities or location of, San Luis
Obispo, Cayucos, Cambria, Nipomo, Santa Margarita,
Paso Robles, Simmler, Shandon, Parkfield, Cottonwood,
Bradley, Las Tablas, and Cuyama. Equipment inventories
vary from station to station, and include fire engines
(both 2- and 4-wheel drive), bulldozers, air companies,
air tankers, and helicopters.
Fires of moderate significance draw responses from
several stations in the nearby area. Since all divi-
sion stations function as part of one organization,
and share a uniform communications network, mobiliza-
tion efforts proceed with efficiency. In the event
of a major fire, local stations could seek almost
unlimited assistance from other CDF stations in the
central coast region, and throughout the State, if
necessary.
Fire abatement in Los Padres National Forest is the
responsibility of the U.S. Forest Service, a federal
agency charged with land use regulation and watershed
management in the nation's forest lands. Since the
USFS is involved primarily with the management and pro-
tection of the wildlands, they have a great deal of
'. 15
experience in combatting fires of a brush and timber
nature. USFS staff fire stations in the areas of
Cuesta, Pozo, Pine Canyon, La Panza, Pacific Valley,
and White Oak. Station inventories and personnel
are similar to those for CDR facilities in the area.
Forest Service fire stations possess coordinated
response capabilities similar to the CDF in that they
operate within one organization and communication
system.
The CDF and the USFS have entered into a mutual aid
agreement for the purposes of wildland fire protection
in San Luis Obispo County. Mutual aid in fire pro-
tection has been defined as a reciprocal arrangement
in which a number of fire protection agencies share
personnel and equipment during emergency situations.
Large scale multi -agency responses to wildland fire
would probably require several hours for the proper
mobilization and delivery of personnel and equipment
to the target area.
Both agencies have developed elaborate response stra-
tegies for specific areas in specific types of weather,
to better prepare for the numbers of variables that
exist in wildland fire abatement. For example, the
Division of Forestry (CDF) has zoned the entire County
as to the types and sizes of fires to be expected during
three levels of fire weather. Each possibility has been
tabulated on a "Wildland Response Card" which is
available to all CDF and USFS stations throughout the
County. Also contained on the response cards are
precise coordinate locations of the area in addition
to the pre -determined strategy (i.e., approach, Nieces
of equipment, and numbers of personnel to be deployed.)
Planning efforts such as this markedly increase the
efficiency- of fire response in the wildland portions of
the County.
0-
2. Urban Fire
This discussion of "urban fire" in San Luis Obispo County
is limited to the risk of structural fire in the rural
portions of the County, which are outside existing com-
munity fire protection districts. In recent times, rural
San Luis Obispo County has experienced growth pressures
that have impacted its existing fire fighting resources.
Personnel and equipment for structural protection in
the rural portions of the County come from the County,
the California Division of Forestry, and volunteer fire
departments maintained in population centers throughout
the rural areas. Authority and administrative respon-
sibilities for rural fire protection have been assigned
to the State Forest Ranger -in -Charge of the California
Division of Forestry, San Luis. Obispo Ranger Units,
who also functions as the. County Fire Warden/Fire Chief.
For the purposes of local planning, three general
levels of fire protection personnel currently exist
in the County. A description of each level, along with
average costs is as follows:
LEVEL I - per year - $ 1,900.00
Volunteer Fire Company with
an average of ten (10) paid
call men per company. Cost
assumes 10 men attending
24 training drills per year
@ $5.00 per man per drill
and 7 men responding to 20
fires per year @ $5.00 per
man per fire.
2.16
LEVEL II - per year - $36,736.00
One (1) Fire Apparatus Engi-
neer (FAE), 24 hours per day,
with direct support provided
by a Volunteer Fire Company.
Cost assumes Level I cost
plus FAE.
LEVEL III - per year - $ 5,030.00
One (1) Fire Apparatus Engi-
neer, 24 hours per day and
one (1) Fireman, 24 hours
per day. At present, there
are two concepts of Level
III manning being used.
1. Per year - $27,667.00
Five and one-half (5h)
months, CDF non -fire
season similar to Paso
Robles Station.
2. Per year - $60,364.00
Year -long protection,
similar to Nipomo Sta-
tion.
Currently, four professional fire-fi'ghtin facilities and
three rural volunteer fire departments ofLr outlying struc-
tural protection throughout the County. A description of
each station along with the relative levels of protection
and budgetary costs are included in the following table:
TABLE 5
EXISTING RURAL STRUCTURAL FIRE PROTECTION FACILITIES
SAN LUIS OBISPO COUNTY
PROFESSIONAL SERVICES
oSimmler - California Valley
Fire Engine - County Owned
Level II ---
Fire Apparatus Engineer - 1 man -
24 hours per day - 12 months
Additional personnel supplied by
Volunteer Company to provide a
minimum of two (2) men on the fire
engine at the scene of the emer-
gency.
* - Includes salaries, vehicle and
radio maintenance, supplies,
gas and oil. Service District
pays utilities, office space,
personnel and apparatus housing.
oNipomo
Fire Engine - County Owned.
Level III ---
Fire Apparatus Engineer - 1 man -
24 hours per day - 12 months.
Fireman - 1 man - 24 hours per
day - 12 months.
* - Includes salaries, vehicle
and radio maintenance, sup-
plies, utilities, gas and oil.
CDF housing, office and equip-
ment storage.
oSan Luis Obispo
Fire Engine - State Owned
Level III ---
Fire Apparatus Engineer - 1 man
24 hours per day - 5� months.
$36,487.00* Fireman - I man - 24 hours per
day - 511 months. (This provides
professional services during non -
fire season.)
* - Includes salaries, vehicle, and
radio maintenance, supplies,
utilities, gas and oil. CDF
housing, office and equipment
storage.
oPaso Robles
Fire Engine - State Owned.
Level III --
Fire Apparatus Engineer - 1 man -
24 hours per day - 51z months.
Fireman - 1 man - 24 hours per day -
$62,880.00* 51i months. (This provides profes-
sional services during non -fire season)
* - Includes salaries, vehicle and
radio maintenance, supplies, util-
ities, gas and oil. CDF housing,
office nad equipment storage.
2.17
$28,500.00*
$28,990.00*
BATTALION CHIEF, DISPATCH, TRAINING AND CLERWAL $71,010.00*
Battalion Chief - 12 months
Training Officer, Fire Captain - 12 months
TABLE 5
o0ak Shores $1,486.00*
(con't.)
Fire Engine - presently owned
by VFC
Dispatch - 24 hours per day - 5N
months CDF non -fire season
Level I ---
Clerical - half-time
10 volunteers - respond with VFC
Fire Apparatus Engineer - County-
fire engine
wide Relief - 12 months
Radio Maintenance and Telephone
* - Includes expenses for volun-
Cost Sharing.
teers responding to fires,
drills and radio maintenance.
Apparatus housing, supplies,
VOLUNTEER FIRE COMPANIES (VFC)
vehicle maintenance, utili-
ties, supported by VFC.
oSimmler $1,300.00*
oSleeper Program $3,000.00*
Level II---
10 volunteers provide Level II
Wages, insurance - 4 men - 5�
manning for Engineer
months (CDF non -fire season)
* - Includes expenses for volun-
2 - San Luis Obispo
teers responding to fires
1 - Paso Robles
and drills.
1 - Nipomo
oSan Simeon $1,487.00*
In an effort to provide the most efficient, and cost ef-
fective structural fire protection throughout rural San
Fire Engine - presently owned by
Luis Obispo County, a 15-minute response time was selected
VFC
as the level of protection to be maintained. However, the
growth of rural communities has rendered existing response
Level I---
capabilities below the desired 15-minute level: To help
10 Volunteers respond with VFC
alleviate that problem, and provide more effective, overall
fire engine
fire abatement, additional stations have been proposed to
become part of the San Luis Obispo County Fire Department.
* - Includes expenses for vol-
Table 6 lists these stations along with the structural
unteers responding to fires,
improvements., populations, and occurrence of fire within
drills and radio maintenance.
15 minutes of the proposed stations.
Apparatus housing, supplies,
vehicle maintenance, utili-
ties, supported by VFC.
2.18
f
TABLE 6
PROPOSED FIRE -FIGHTING FACILITIES
SAN LUIS OBISPO COUNTY
1974
Level of 5-Year Fire Non-Fire(d)
Station Improvement(a) Population(b) Protection Occurrence(c) 1974 Fire Occurrence(c) Emergencies
San Luis Obispo:
Rural $41,734,898.00 7,572 III 230 72 38
Airport 4,858,040.00 ----- it ---
(e) Airport
Aircraft 1,401,300.00 ----- --- __-
Nipomo: 12,611,414.00 9,702 11 379 95 63
Santa Margarita: 1,9S0,748.00 1,125 III 83 45 20
Cambria (f): 21,499,145.00 1,120 1II 21 10 12
(a) 'Taxable wealth- improvements are exclusive of land, utilities and unsecured
property. Assessors Office.
(b) Population - Planning Department. -
(c) CUP Fire Statistics - 1969 - 1973 and 1974.
(d) CDF Non -Fire Emergencies - 1974 - Rescue, flammable liquid hazards, public
safety assists, etc.
(e) Coimnercial and private aircraft values - 'fax Collectors Office.
(f) Exclusive of Hearst Castle and Contents.
Source: Rural Structural Fire Protection Plan 197.1-75 San Luis Obispo County.
2.19
2. City of San Luis Obispo and Vicinity
a. Wildland Fire Danger
Weather, vegetation and topography combine in San Luis
Obispo to create one of the more hazardous wildland fire
situations in the county. Critical "fire weather" is
frequent. The city is surrounded by significant stands
of flammable vegetation. And most of the area is hilly --
much of it steep. The greatest fire danger exists where
both steep terrain and highly flammable vegetation are
part of the mix, but in some places one factor might be
so severe that it warrants the highest possible fire -danger
designation.
On fire -danger maps for the San Luis Obispo area, weather
is assumed to be the same for all parts of the area.
Vegetation and topography are the factors that make danger
levels vary from place to place. But since the city is in
the most critical fire -weather category, danger levels
generally are higher than they would be in areas with less
frequent critical fire weather.
Because of its size and location next to potential wild -
land fire areas, the City of San Luis Obispo had been
mapped for this type of hazard at the scale of 1" = 2,000'
Four levels of wildland fire danger have been identified
for the area: extreme, high, moderate and low. (The
natural hazards map is enclosed with this document.)
Most urban development in the city has occurred in flatter
areas, away from the more Eire -prone hillsides. That aspect
helps reduce the chances of injury and property damage.
The urbanization that has occurred outside of the well-
defined urban envelope has been restricted to the disturbed
grassland areas, designated a moderate fire hazard in this
analysis.
Primary responsibility for_the abatement of wildland fire risks
belongs to the California Division of Forestry and, to a lesser
extent, the City of San Luis Obispo Fire Department. The CDF
maintains a station on Highway One, north of the city, near the
more fire -prone areas.
These are the wildiand fire -danger classifications and the types
of areas that fit each one:
Extreme Fire Danger
Extreme fire danger occurs in several parts of the study area.
These generally are the steepest slopes where access is most
difficult, and where vegetation is highly flammable and fully
developed -- dense chaparral and oak woodland, for example. They
include the upper parts of the Santa Lucia Mountains, Santa Lucia
Foothills and other ridges and peaks near San Luis Obispo. Many
of these areas have had wildland fire problems in the Mast.
High Fire Danger
In high -danger areas, slopes are less steep than in extreme -danger
areas, hot access is stili difficult. These areas include, for
example, the lower slopes of the Santa Lucia Foothills and the
Santa Lucia Mountains. Vegetation in these areas generally .is
highly flammable, but is north coastal scrub or light Lbaparrai,
which won't horn with the same intensity as vegetation in
extreme -danger areas.
Moderate Fire Danger
Moderate -danger areas usually are flatter areas dominated
by grassy vegetation and scattered oak woodlands, including
croplands and well -grazed pastures on lower slopes. Since
such vegetation burns with only moderate intensity, and
since these areas are not so steep, fire is easier to
control. But the potential for wildland fire in these areas
cannot he overlooked.
Low Fire Danger
Low -fire -danger areas are dominated by two distinct
types: (1) developed areas that don't include
significant areas of native vegetation and (2)
riparian areas along stream courses. Vegetation
in these areas characteristically retains enough
moisture in its leaves to effectively retard fire.
"No Danger" or "Nil"
This category usually includes only areas of standing
surface water. None is shown in the San Luis Obispo
study area. Laguna Lake itself could be classified "no
danger," but for mapping purposes it has been averaged
into the shoreline and surrounding areas as moderate
or low danger.
b. Urban Fire Risk
1. Area Setting
The City of San Luis Obispo, with a population of
approximately 35,400 ranks as the largest, most
diverse urban center in San Luis Obispo County.
Located within or in the vicinity of the city are
a major university, multi -story county administrative
buildings, a significant percentage of multi -family
residential developments, and several commercial
districts and industrial areas. In recent years,
San Luis Obispo has experienced fairly rapid growth,
as is reflected in its increasingly urban nature.
As the City of San Luis Obispo grows, its fire
protective forces face increasingly complex fire
hazards. Currently, the city has the most diverse
urban fire fighting situation in the county. This
is not to say that there will necessarily be more
fires in San Luis Obispo than in other locations,
2.21
but the potential for problems is greater in the city than
elsewhere in the county.
The city has responded to the growing complexity of its
fire fighting situation by developing the largest and
best equipped urban fire department in the county. The
City of San Luis Obispo Fire Department is charged with the
responsibility of fire prevention for the city. It currently
operates from three fire stations located in the following areas:
(1) Foothill Boulevard and North Chorro Street
(2) Chorro Street and Marsh Street
(3) Augusta Street and Laurel Lane
A new station under construction at the corner of Madonna and
Los Osos Valley roads is expected to he ready for use by the
end of May 1978.
The city Fire Department is a full-time professional department
employing one chief, three battalion chiefs, one fire marshall,
three permanent fire inspectors, two temporary fire inspectors,
one investigator, 10 fire captains, nine fire engineers and 12
fire fighters.
The Fire Department's inventory of rolling fire -response equipment
includes the following:
1250 gpm pumpers
85-foot aerial ladder truck
75-foot aerial ladder "scope" truck (expected in
service by July 1, 1978)
reserve pumpers
state-owned reserve pumper available to the city
The city's fire defenses tare currently ranked by the Insurance
Office as Class 3 for the more central portions of the city, and
Class 9 for the chiefly undeveloped outlying arras. The primary
reason for this decrease in rating is the fact that there is no
water available from the city in these areas.
Fire Incidence
Data compiled by the city Planning Department over
the period 1969-1973 indicates that approximately
178 fires occur annualy in the City of San Luis
Obispo. The majority of these fires involve struc-
tures, but do not always cause major damage. Kitchen
fires, a primary component of structural fire sta-
tistics, inflate these figures somewhat above the
level of damages actually incurred. The following
table indicates the numbers, and types of fire which
have occurred in the six major areas of the city.
2.22
T.
J
TABLE 7
FIRE INCIDENCE
CITY OF SAN LUIS OBISPO
1969
1970
1971
1972
1973
1969-1973
u
u
a
u
u
U
(n
f�/qL�
uu
u
M
U
w
:n
a
U
H
U
m
VI
(��J�+
a
u
H
U
(n
!14�A
a
a
c)
H
UHj
rn
chi
UUg47
tn
(n
COLLEGE
9
5
1
8
5
5
3
1
5
2
6
3
8
3
5
l
7
5
1
5
34
30
16
18
JOHNSON
14
5
6
16
14
6
4
14
11
7
6
3
20
10
4
11
12
7
7
9
71
35
27
53
FOOTHILL
8
7'
5
10
9
10
4
6
23
21
19
11
6
4
2
4
10
3
41
1
56
45
34
32
DOWNTOWN
2S
15
13
21
37
17
14
5
11
3
9
11
23
24
10
15
24
21
12
8
120
80
58
60
LAGUNA
1 3
7
-
7
S
3
4
7
4 1
6
2
7
4
4
6
8
3
S
S
5
19
25
17
34
EDNA/AIRPORT
-
1
1
3
4
1
1
2
2
2
-
3
4
1
2
-
5
4
I
4
15
9
5
12
TOTALS
59
40
26
63
74
.42
30
35
56
41
42
38
65
46
29
39
61
45
30
32
315
214
147
209
SOURCE: City of San
Luis Obispo
Planning Department
2.23
As is illustrated in the preceding table, more fires of
each type occur in the City's downtown than in any
other single location. This is perhaps to be expected
for structural fires and vehicle fires. However, when
analyzing grass fire occurrences, such results are some-
what unusual. The probable cause for this is the number
of vacant lots, overgrown with weeds, that exist in the
downtown area. Children will often seek out these areas
during play, and accidentally ignite the accumulated
debris with matches or other lighted materials.
3. Response Corridors/Evacuation Routes
Response corridors are defined as primary routes along
which emergency vehicles, including fire department
equipment, travel when responding to a fire or another
emergency. Response corridors are usually primary or
secondary roads that offer sufficient width for fire
vehicles. Roads chosen as response routes usually
follow the most direct paths to the various parts of
the community. However, response corridors are often
the more attractive routes for general traffic flow:
a situation which sometimes results in traffic con-
jestion and delays in emergency response.
Primary response routes in the City of San Luis
Obispo include Higuera Street, Marsh Street, Pismo
Street, Johnson Avenue, Broad Street, Madonna Road,
Highway 101, Chorro, Santa Rosa, California Blvd.,
Monterey Street, and Madonna Road for Fire Station
ill; Foothill Blvd, Santa Rosa, Monterey Street,
California Blvd., Grand Avenue, Chorro Street, Broad
Street, Highway 101, and Madonna Road for Fire Station
N2; Johnson Avenue, Laurel Lane, Orcutt Road, Broad
Street, South Street, and Higuera Street for Fire Sta-
tion 03. (SLO City Fire Department, 1974).
Evacuation routes as defined in Section VI, Emergency
Preparedness, often adhere to major response corri-
dors. Such is the case in the City of San Luis Obispo.
2.24
4. Potential Hazards
Potential hazards that exist in any city, including San Luis
Obispo, are many and depend on the types and intensities of
land uses which occur in the area. However, the implemen-
tation of fire defenses serves to reduce the likelihood
of hazards to acceptable levels. Maintaining adequate fire
flows, response times, personnel and equipment is crucial
in preserving adequate levels of fire prevention.
As is reflected in its ISO classification, the City of San
Luis Obispo is, in general, well -protected from urban fire.
However, some exceptions to this general statement exist.
A major fire protection hazard in the City is related
to the lack of a fire fighting station to serve the devel-
oping areas of Laguna Lake and Los Osos Valley. Fires in
these areas cannot be reached from existing facilities
within a four -minute period. It has been established that
a total elapsed time of four minutes is the maximum time
which a citizen should have to wait for the arrival of
fire fighting units. The determination of four minutes is
based on the fact that most fires in (or endangering)
builldings gain sufficient headway so that they are beyond
the control capability of firefighting personnel responding
from fire stations located more than 21z or 3 miles from
the fire location, or otherwise delayed as the result of
heavy -traffic areas, topographic obstructions, etc. (SL)
City Fire Department, 1974).
Mitigation measures have been offered by the City Fire
Department that would alleviate a portion of the problems
associated with unduly long response times until a new
facility can be constructed in the south area. These
measures are contained in the (:ity's Resolution Number 2771
I1117S Series). Briefly, some of the measures include:
Prohibition of construction which will require more
than 1500 GPM fire flow flow for fire protection unless
approved automatic sprinkler protection is provided.
2.
Prohibition of construction of buildings exceeding
surface streets in the City are also utilized as primary
5000 square feet in area unless approved automatic
response corridors by the Fire Department. The traffic
heat and smoke detection systems are provided.
associated with these response routes effectively delays
response capabilities for emergency vehicles.
3.
Prohibition of construction of buildings exceeding
.
two (2) stories in height unless windows required
3. Response delays associated with topographical features.
for rescue of occupants can be reached with ladders
San Luis Obispo is a City well -divided by natural topo-
carried on fire department pumpers.
graphy and man-made surface features. Such separations
as the Southern Pacific Railroad, U.S. Highway 101, San
4.
Prohibition of construction of buildings not provided
Luis Obispo Creek and the mountains to the west of the
with fire -retardant roof coverings.
City effectively bisect the area into many different
subareas. The significance of these features becomes
5.
Prohibition of construction of buildings exceeding
more apparent when access is needed during periods of
150o square feet in area unless provided either
high environmental stress, such as during the flood of
with (1) wall and ceiling protection such as 'one-
January 1973. Disasters of that variety can render
hour fire -resistive construction throughout", or
already -limited crossings virtually useless to emer-
(2) with automatic sprinkler protection or (3) with
gency response vehicles.
installation of automatic smoke detection equipment.
4. hazards associated with community infrastructure. The
Other fire safety issues that exist in the City include
existence of infrastructure (oil pipelines, gas lines,
the
following:
and electrical transmission lines in particular) can
increase an area's exposure to fire and explosion.
1.
Insufficient fire flows in portions of the City.
Although facilities of these types are designed to
The Criteria used to define fire flow deficiencies
withstand significant environmental disruptions, failures
include a minimum requirement of 500 gpm for low
have been known to occur, resulting in pipeline rupture
and medium density residential areas; and a mini-
or transmission line collapse. Failures are most likely
mum of 1500 gpm for multi -family residential,
to be non -seismic in nature (see Section IV C: Effects
commercial and industrial land uses.
on Utilities). They are more likely to be caused by
faulty pipes, accidental puncturing, or, in the case
An overlay showing existing land use and fire flows
of power lines, high winds. The City is traversed by
was employed in developing the fire flow deficiency
several oil, gas and electrical lines that serve the
areas that exist in the City. 'these areas, which
area and transport these commodities to other locations.
appear on the Urban Fire hazards Map for the City,
are generally restricted in size; but are found
throughout the developed portions of the City.
2.
Response delays associated with traffic congestion.
Recent traffic studies available to the City Fire
Department indicate that the most heavily travelled
2.25
3. City of Morro Bay
a. Wildland j'ire Hazards
The City of Morro Bay does not face major wildland
fire threats due to its environmental setting. Vege-
tation in the area is limited primarily to low growing
grasses and scattered shrubs, the characteristic Vege-
tation of disturbed Northcoastal Grasslands. Another
fire -limiting characteristic of this area is the cool,
marine -influenced climate. Temperature extremes do
not occur very often, nor does the relative humidity
decline to critically -low fire hazardous levels.
The only wildland area which deserves special consider-
ation in the Morro Bay is the Black Hill, Cerro Cabrillo
area south of the City. Native vegetation in this area
approaches levels capable of supporting a localized wild -
land fire. However, the climate, and land use character-
istics of that vicinity make ignition unlikely.
b. Urban Fire Risk
1. General Setting
The City of Morro Bay has a population of 8,875 (January
1975) and ranks as the second largest incorporated city
in San Luis Obispo County. In terms of diversity
of land uses and overall developed density, the City
of Morro Bay ranks below larger cities, such as San
Luis Obispo. The fire hazards situation is therefore,
less complicated in a city the size and stature of Morro
Bay.
The City of Morro Bay Fire Department is charged with
the responsibility of fire protection in the City. It
currently operates from a single station located at
715 Harbor Street. The Department is staffed by both
professional personnel and volunteers, and includes the
following:
Professional Volunteer Position
1 - Chief
3 S Captains
5 8 Engineer
1 7 Fire fighters
The Fire Department's inventory of rolling fire response
equipment includes the following:
2 1000 gpm pumpers
1 750 gpm pumper
1 Ton Squad Truck
1 Chief's Car
1 Pickup
In addition to the above equipment, the City also main-
tains a fire boat which is used in responding to boat,
dock, pier, and general waterfront fires. A subsidized
private ambulance is also available for emergency response
in the City.
The City's fire defenses are currently rated by the Insu-
rance Services Office as Class 5 for the more central por-
tions of the City and Class 9 for the beach area and out-
lying locations to the east and south. The primary reason
for this decrease in protections rating is the lack of water
and adequate response routes in these areas_ Response to
fire emergencies in the City proper requires a maximum of
four minutes.
2. Potential Hazards
Four potential urban -oriented fire hazardous situations
exist in the Morro Say area. They are:.
1) Inadequate water supplies in the more
northerly -sections of the City.
2) Poor access in and around the waterfront
2.26 areas during tourist season.
3) Access problems associated with
operation from one fire station.
4) The existence of the Pacific Gas
and Electric Power Plan and sup-
porting tank facilities.
The fire problems associated with inadequate water
supplies are Morro Bay's major problem, relative
to the other three. As is indicated on the Natural
Hazards Map, the City of Morro Bay, certain areas along
Sequoia Avenue, Aldea Avenue, and Atascadero Road
do not possess adequate water supplies. This requires
the City Fire Department to lay longer hose lengths
when combatting fires in these areas. This problem
is recognized by the City which plans to upgrade fire
flows in the City according to the priority areas
shown on the Natural Hazards Map.
Access to the beach area, the second fire problem, is
seasonal in nature and is caused by the traffic con-
gestion and parking violations which commonly occur in
that area. Emergency responses to dock fires or
boating emergencies could be hindered by congestion in
this location.
The third problem is of somewhat lesser significance,
but still warrants consideration. Fire departments
that operate from one station run the risk of being
isolated from potential emergencies if critical trans-
portation links become jeopardized during periods of
extreme environmental stress. Such a situation is
possible in the City of Morro Bay. Emergency access to
the northerly sections of the City is directly linked
to the passabiIity of Highway One across Morro Creek.
Although the bridge is not susceptible to more periodic
floods, its performance has never been tested during a
storm producing a flood of the 100-year frequency.
Fire protection in smaller cities and communities is
often limited to a central facility which serves the
entire community. Therefore, this problem is commonly
encountered in such areas. Morro Bay has, in the past,
2.27
operated a station in the north city. If population
trends continue, and the north area continues to grow
in terms of population and structural units, it may
become necessary to reopen a north city facility. The
City is considering locating a new station at the south-
east intersection of Highway 46 and North Main Street.
The fourth fire problem is associated with the existence
and functioning of the Morro Bay electrical generating
facility operated by the Pacific Gas and Electric Company.
Although units of this type have substantial safety pre-
cautions engineered into their design, certain risks still
remain.
The community itself is faced with greater risk from the
infrastructure which transports resources to and from
plants of this type.
The existence of infrastructures (oil pipelines, gas lines,
and electrical transmission lines in particular) can in-
crease an area's exposure to fire and explosion. Although
facilities of these types are designed to withstand signi-
ficant environmental disruptions, failures have been known
to occur resulting in pipeline rupture or transmissionline
collapse. Failures are most likely to he non -seismic in
nature (see Section IV C: Effects on Utilities). They
are most likely to be caused by faulty pipes, accidental
puncturing, or, in the case of power lines, high winds.
3. Response Corridors/Evacuation Routes
Response corridors are defined as primary routes along
which emergency vehicles, including fire department equip-
ment travel when responding to a fire; or similar emergency.
Response corridors are usually primary or secondary roads
that offer sufficient width for fire vehicles. Roads chosen
as response routes usually follow the most direct paths to
the various parts of the community. However, .response cor-
ridors are often the more attractive routes for general
traffic flow: a situation which sometimes results in
traffic congestion and delays in emergency response.
Primary response routes in the City include Morro
Bay Boulevard, Harbor Street, Main Street, Highway
One, Kern Avenue, Atascadero Road, and South Bay
Boulevard.
Evacuation routes as defined in Secton VI, Emergency
Preparedness, often adhere to major response corridors.
Such is the case in the City of Morro Bay.
2.28
4. City of E1 Paso de Robles
a. Wildland Fire Hazards
The City of E1 Paso de Robles is situated in the Southern
Salinas River Valley, adjacent to the foothills of the
Santa Lucia Range. The climate of the area is moderate,
and is characterized by dry, warm summers and moderately
wet winters. The climatic influence and physiography
of the region, which includes Paso Robles, have provided
the necessary components for a variety of natural vegeta-
tive types. Extensive oak woodlands, grasslands and
stands of chaparral occur in various areas of the
regions. All of these plant communities contribute to
a relatively high degree of wildland fire risk. How-
ever,, most of the development in the Paso Robles area
has occurred in the flatter portions of the area, away
from the more fire prone hillside locations. What
development has occurred to the west of the City, has
been basically agricultural in nature, a land use which
mitigates much of the risk associated with wildland
fi re.
The risk of wildland fire in the Paso Robles area is
localized and moderate, and is basically confined to
those low density residential areas located near growths
of significant native vegetation. Those areas include
the Norn Hill and Peachy Canyon areas, both of which
are outside the City proper.
b. Urban Fire Risks
(1) General Setting
Paso Robles is a mature, moderately well developed urban
area with a population of approximately 8,195. It is
the County's fourth largest incorporated City, and the
fifth largest urban center. The City also operates the
Paso Robles Municipal Airport, the second busiest public
airport facility in the County (based on numbers of
operations). Land uses in Paso Robles are essentially
residential, commercial, and agricultural, with single1. 19
family structures and commercial shops comprising most
of the City's structural types. The City also has a
number of industrial companies which are involved in the
production of electronic components, printed business
forms, and wholesale meat. One of the leading industrial
complexes is an almond processing plant.
The City of Paso de Robles Fire Department is charged
with the responsibility of fire protection in the City.
It currently operates from three stations, located at
13th Street and Oak Street, Santa Fe Avenue in the Sherwood
Acres area, and The Paso Robles Municipal Airport. The
City Fire Department is staffed with a professional fire
chief and a complement of 47 volunteer officers and fire
fighters.
The Fire Department's inventory of rolling fire response
equipment includes the following:
1 150 gpm pick-up
1 1250 gpm pumper
2 1000 gpm pumper
1 850 gpm pumper (reserve)'
2 Patrol Units (150-250 gallon capacity)
1 Fire boss unit-450 gallons dry chemical
-50 gallons light water (foam)
I Rescue Unit (with medical technician for
response to Freeway/Highway accidents)
The City's fire defenses are currently ranked by the
Insurance Services Office as Class 5 for the more central
portions of the City and Class 9 for certain undeveloped
eastern areas of the City. The primary explanation for
this decrease in protection is the lack of roads in
affected areas. Little development has taken place in these
lesser protected areas. Response to fire emergencies in
the developed portions of the City requires approximately
three minutes.
The City Fire Department has entered into mutual aid
agreements with the Atascadero Fire Protection Ilisu•ict
and the California Division of Forestry.
Mutual aid in fire protection has been defined as a
reciprocal arrangement in which several fire protection
agencies share personnel and equipment during emergency
situations. Mutual aid accomplishes an increase in
fire protection capabilities at minimal extra cost.
However, mutual aid operations usually lack the efficiency
of operations involving only one department.
The City responds to approximately 40-45 alarms per year.
Of these, approximately one-third (1/3) involve structures,
and most of these are limited fires.
Paso Robles is provided with sufficient water supplies
for fire prevention. Storage capacity exceeds 8,000,000
gallons in the two City reservoirs, and seven wells at
varying depths tap the aquifers created in part by the
Salinas River. Few areas in the developed portion of
the City are more than 300 feet from a functioning fire
hydrant.
(2) Potential Hazards
Potential hazards in the City of Paso de Robles are
generally related to (1) the presence of the airport and
related industries, (2) Highway 101 and the Southern
Pacific Railroad that traverse the City in a north -
south direction, and the presence of potentially hazardous
utility lines in the City.
Paso Robles Municipal Airport ranks as the second largest
airport in San Luis Obispo County, with about 60,000
operations annually. The requirements for fire protection
in the event of a crash, emergency landing, or fuel
explosion create a significant need for additional safety
considerations in the area. These needs are presently
met by the fire station operated by the City which is
located in the airport area. Evaluations contained within
the Master Plan for Paso Robles Munici al Air art, McGlasson
and Associates, Consulting Engineers, ave found existing
protection adequate for maintaining acceptable safety
levels.
2.30
The Southern Pacific Railroad and highway 101 traverse
the area in a north -south direction. The fire hazards
associated with the presence of these facilities relate
to the flammable and caustic materials often transported
in rail -mounted tank cars and highway trucks. No major
disasters of this type have occurred to date, but the
possibility of a future accident cannot be precluded.
The third potential hazard arises from the presence
of standard energy -dispensing utilities that traverse
the area. The existence of infrastructure (gas
lines and electrical transmission lines, in part-
icular) can increase an area's exposure to fire and
explosion. Although facilities of these types are
designed to withstand significant environmental dis-
ruptions, failures have been known to occur, resulting
in pipeline rupture or transmission line collapse.
Failures are most likely to be non -seismic in nature
(see Section IVC: Effects on Utilities). They are more
likely to be caused by faulty pipes, accidental punc-
turing, or, in the case of power lines, high winds.
(3) Response Corridors/Evacuation Routes
Response corridors are defined as primary routes along
which emergency vehicles, including fire department e(Im p-
ment, travel when responding to a fire, or similar emer-
gency. Response corridors are usually primary or secondary
roads that offer sufficient width for fire vehicles.
Roads chosen as response routes usually follow the
most direct paths to the various parts of the commtniity.
However, response corridors are often the more attractive
routes for general traffic flow - a situation which
sometimes results in traffic congestion and delays in
emergency response.
Major response routes in the Paso Robles area include:
Vine Street,. Spring Street, Pine Street, Riverside
Avenue, 13th Street, Niblick Road, Creston Road, U.S.
Highway 101 and highway 40.
Evacuation routes as defined in Section VI, Emergency
Preparedness often adhere to major response corridors.
Such is the case in the City of Paso de Robles.
2.31
S. City of Pismo Beach
a. Wildland Fire Hazards
The City of Pismo Beach is confronted with no signi-
ficant wildland fire hazards. The potential for
fire exists in the Pismo Hills, to the west of the City,
where occasional steep slopes and open space interact to
create a potentially hazardous area. However, heavy
livestock grazing along these hillsides has removed
much of the grasses, and lowered the threat of fire
in that area. Grazing has been so intense that the
hazards caused by erosion outweigh the fire risks in
the area.
b. Urban Fire Risk
(1) General Setting
Pismo Beach is a moderately well -developed, recreationally
oriented urban area, with a resident population of 5,423
(July, 1974). However, during the summer months the
City's population increases by as much as 100% because
of influx of summer residents and vactioners.
Urban land uses within the City are primarily residential
and commercial. A significant portion of the residential
acreage and total structural units in the City are of,
the medium and high density variety, such as hotels,
apartments, and condominiums. These structures, along
with the schools, theaters, and other places of assembly
constitute the City's most critical areas in regards to
urban fire safety.
Pismo Beach is served by the Pismo Beach Fire Department,
the agency primarily responsible for the City's fire
protection and emergency response needs. It is a vailun-
teer organization, numbering 22 volunteers and headed
by a professional fire chief. The Fire Department operates
from two facilities, located at Bello and Pismo street
(main station), and the Pacific Coast Highway, in the
vicinity of the Andrews -Shell Beach area. The Fire
Department's inventory of rolling fire response equipment
2.32
includes the following:
1 1250 gpm pumper
2 1000 gpm pumpers
1 750 gpm pumper
1 500 gpm pumper
2 Rescue Units
1 Utility Jeep
The City Fire Department is capable of responding to
an alarm in the developed portion of the City within two
minutes. The City's fire defenses are currently rated
by the Insurance Services Office as Class S for
that portion of the City to the west of the Southern
Pacific Railroad, and Class 9 for the incorporated
areas east of the railroad. Virtually all of developed
Pismo Beach is located in the Class S protection zone.
The City of Pismo Beach Fire Department has entered
into mutual aid agreements with the City of Arroyo
Grande Fire Department and the Grover City Fire
Department, as well as the California Division of
Forestry and the Oceano Volunteer Fire Department.
Mutual aid in fire protection is a reciprocal au•range-
ment in which several fire protection agencies share
personnel and equipment during emergency situations.
Mutual aid accomplishes an increase in fire protection
capabilities at minimum extra cost. ilowever, mutual
aid operations usually lack the coordination and
efficiency of operations involving only one department:
Pismo Beach is generally well supplied with water for
the purposes of fire prevention. Fire flows in the
principal business district are approximately 3500 gpm,
while flows in other commercial and high density resi-
dential area average between 2000 gpm and 3500 gpm. A
minimum flow of 1000 gpm is maintained in the City's
low and medium density residential areas. 'fhe t:ity's
overall water storage capacity is approximately
2,000,000 gallons in the City's five reservoirs and
Lake Lopez allotment. There are fire flow problems
'� i
O
in specific areas, however, which result from the
lack of shut-off valves and inadequately sized routes
and water lines. This hazard is discussed below.
(2) Potential Hazards
Potential fire hazards in the Pismo Beach area are
related to (1) the lack of adequate fire flows in
certain areas, (2) the influx of population during
tourist season, (3) the potential pressures for high
rise development in the City, and (4) the presence of
the Southern Pacific Railroad to the east of the City,
and Highway 101.
A recent evaluation of the City's water system by the
City Engineer concluded that water pressure was inade-
quate in a number of areas, and that the downtown area
water lines were lacking shutoff valves. The areas
affected by lack of water pressure are Spyglass Point
and parts of St. Andrews. The City Council has recog-
nized the potential hazards created by these fire flow
problems, and has authorized engineering studies for
placement of 5,000 feet of 16-inch line between Spyglass
Point and the water reservoir along Mattie's Road. In
addition, approximately 200 feet of 6-inch line between
Terrace Avenue and the Lopez turnout will be replaced
with 12-inch line.
The population of Pismo Beach increases significantly
during the summer months, as has been previously discussed.
An emergency situation occurring in conjunction with the
tourist season could conceivably exceed the City's fire
protective and emergency response capabilities, especially
if large evacuations were made necessary. Another
aspect related to this situation is the congestion which
normally accompanies busy weekends and vacation periods.
Access problems, similar to those encountered along Cypress
Street throughout the year, are made more likely in the
beach area, by the influx of beach -oriented vacationers.
Crowded streets could increase the risks of extensive
fire damage by impeding the efficient response of both
fire equipment and personnel.
2.33
Pismo Beach is currently the only City in the Pismo
Beach -Arroyo Grande -Grover City area that includes struc-
tures over three stories in height. Similarly, it is the
City most likely to encounter future pressures for high
rise development. Multi -story structures can represent
significant potential fire threats. Dependence on
internal support systems, including ventilation, water
availability and pressure, and elevator systems increase
the sensitivity of high-rise structures. Such systems
may fail during a fire, when they are most critically
needed. Many cities confronted with the potential
hazards of high rise development require all multi -storied
structures to incorporate sprinkler systems in their
design. Of the most commonly available private fire
protection facilities, the automatic sprinkler system
remains the most effective. Records of more than 120,000
fires show that 96% were extinguished or satisfactorily
checked by sprinklers.
The Southern Pacific Railroad and Highway 101 traverse
the area in a north -south direction. The fire hazards
associated with the presence of these facilities relate
to the flammable and caustic materials often transported
in rail -mounted tank cars and highway trucks. No
major disasters of this type have occurred to date, but
the 'possibility of a future accident cannot be precluded.
The Pismo Beach Fire Department assumes the respon-
sibility for fire response along Highway 101 from the South
County boundary to Avila Road, north of the City. An
emergency situation involving the railroad, however,
would involve other local agencies.
(3) Response Corridors/Evacuation Routes
Response corridors are defined as primary routes along
which emergency vehicles, including fire department
equipment, travel when responding to a fire, or similar
emergency. Response corridors are usually primary or
secondary roads that offer sufficient width for fire
vehicles. Rows chosen as response routes usually follow
the most direct paths to the various parts of the
canununity. However, response corridors are often the
1
most attractive routes for general traffic flow - a
situation which sometimes results in traffic con-
jestion and delays in emergency response.
Response routes for the City of Pismo Beach include:
Bello Street, Price Street, U.S. Highway 101, Dolliver
Street, Bay Street, El Portal Street, Wadsworth Street,
and Five Cities Drive.
2.34
6. City of Arroyo Grande
a. Wildland Fire Hazards
The City of Arroyo Grande is located in the generally
flat valley drained by Arroyo Grande Creek. The
flatter portions of the area have been developed into
urban, or agricultural land uses, while the hilly por-
tions of the City to the north and east remain in a
semi -natural open woodland state. Certain of these
hilly areas represent moderate wildland Eire risks
to the more outlying portions of the City.
Several factors help mitigate the potential for large
fires in the Arroyo Grande area. The natural vegeta-
tion of the area is not dominated by the more fire -prone
chaparral species, nor are sizeable amounts of plant
litter allowed to develop. Cattle grazing helps reduce
much of this accumulation.
b. Urban Fire Risk
(1) General Setting
The City of Arroyo Grande has a population of 8,550
(July, 1974) and is the third largest incorporated
City in San Luis Obispo County. In terms of diversity
of land uses and overall developed density, the City of
Arroyo Grande ranks below larger citiesi such as
San Luis Obispo. The resultant fire hazards situation
is, therefore, less complicated in a city the size of
Arroyo Grande.
The City of Arroyo Grande Fire Department is charged
with the responsibility of fire protection in the City.
It currently operates from a single station located at
215 Gast Branch Street. The Department is staffed with
a professional fire chief and a complement of 38 volun-
teer officers and fire fighters.
The Fire Department's inventory of rolling fire response
equipment includes the following:
1 2500 gallon water tanker*
1 1000 gpm pumper
1 1250 gpm pumper
1 Mini -Attack vehicle
1 Rescue vehicle
The City's fire defenses are currently ranked by the
Insurance Services Office as Class 5A for the more central
portions of the City, and those areas that are unavailable
to the City's water system and lack hydrants are assigned
a Class 9 for insurance purposes. Response to fire emer-
gencies within the City's built up area does not exceed
four (4) minutes.
The City Fire Department has entered into mutual aid agree-
ments with the California Division of Forestry and the fire
departments of Santa Maria, Oceano, Grover City, and Pismo
Beach. Mutual aid in fire protection has been defined -as
a reciprocal arrangement in which several fire protection
agencies share personnel and equipment during emergency
situations. Mutual aid accomplishes an increase in fire
protection capabilities at minimal extra cost. However,
mutual aid operations usually lack the efficiency of opera-
tions involving only one department.
The City recently acquired the mini -attack vehicle listed
in the preceding inventory. Its capabilities range from
wildland fires to structural fires of limited extent. The
mini -attack vehicle is more maneuverable than the larger 750,
1000, and 1250 gallon capacity pumping units, and is capable l
of performing tasks once thought to be solely within the
realm of larger pumping vehicles. In Arroyo Grande, this
unit works in conjunction with its larger counterparts in
a mini -maxi attack for the majority of emergency assignments.
It should also he noted that the Arroyo Grande Fire Department
frequently has eight (8) emergency medical technicians at
its disposal, and is well equipped for related rescue assign-
ments and vehicle extrication.
The City Fire Department responds to approximately So alarms
pei` year. Of these, approximately 20% involve sti-uctures and
most of these are limited fire.
'.35 'Available on request from Public Works Department.
The City of Arroyo Grande has provided sufficient
supplies of water and hydrants for the purposes of fire
protection. Few areas within the developed portion
of the City are beyond 300 feet from a functioning
fire hydrant.
(2) Potential Hazards
Potential hazards in the City of Arroyo Grande are
generally related to (1) the presence of certain
potentially hazardous land uses, and (2) the lack of
multiple fire -fighting facilities in the City. Neither
of these potential problems are major concerns, but
neither should be overlooked.
City. The existence of infrastructure (e.g. oil pipe-
lines, gas lines, and electrical transmission lines, in
particular) can increase an area's exposure to fire and
explosion. Although facilities of these types are
designed to withstand significant environmental disrup-
tions, failures have been known to occur, resulting in
rupture or transmission line collapse. Failures are most
likely to be non -seismic in nature (see Section IIIC:
Effects on Utilities). They are more likely to be caused
by faulty pipes, accidental puncturing, or, in the case of
power lines, high winds.
(3) Response Corridors/Evacuation Routes
Response corridors are defined as primary routes along
The C_i_ty contains areas of high density residential which emergency vehicles, including fire department
and light commercial/industrial land uses, each of which equipment, travel when responding to a fire, or similar
requires complex fire fighting strategies. Portions emergency. Response corridors are usually primary or
of the City's industrial areas are concerned with secondary roads that offer sufficient width for fire
the distribution of pesticides, insecticides, and vehicles. Roads chosen as response routes usually follow
fertilizers. Such chemicals present hazards through the most direct paths to the various parts of the commu-
fire and explosion, as well as corrosion. High nity. However, response corridors are often the more
density residential developments concentrate large attractive routes for general traffic flow: a situation
quantities of combustible materials in confined areas which sometimes results in traffic congestion and delays
with limited access. Both of these factors complicate in emergency response.
fire fighting procedures.
Fire Departments, such as Arroyo Grande's., which
operate from a single station, run the risk of being
isolated from potential emergencies if critical trans-
portation links become jeopardized during periods of
extreme environmental stress or traffic conjestion.
However, Arroyo Grande's location helps minimize the risk
of occurrence. In an emergency, the City Fire Depart-
ment. Both of these agencies are located in sufficient
proximity to offer assistance within minutes.
A third potential hazard arises from the presence of
standard energy -dispensing utilities that traverse the
2.36
Primary response routes in the City of Arroyo Grande
include Branch Street, Traffic Way, Valley Road,
Cherry -Branch Mill Road.
Evacuation routes as defined in Section VI, lmergency
Preparedness., often adhere to major response corridors.
Such is the case in Arroyo Grande.
7. Grover City
a. Wildland Fire Hazards
Grover City is confronted with no major wildland fire
hazard risks. Its location, adjacent to the Pacific
Ocean and away from vegetated hillsides possessing
heavy potential fuel loads, effectively reduces wild -
land fire hazards. Open areas, populated by annual
grasses, still exist within the City, but insufficient
fuel is present to maintain large scale natural fires.
Smaller fires might break out in these grassy areas
during the drier months of late summer, though it is
doubtful they would spread far beyond the point of
ignition.
b. Urban Fire Risk
(1) General Setting
Grover City, with a December, 1974 population of 7,225
(Department of Finance) comprises approximately 2.3
square miles of land area west of Arroyo Grande,
adjacent to the Pacific Ocean. Approximately 27%
of the City's total land area has undergone urban
development, while the remaining 73% has been used
for agriculture, recreational open -space and ,public
rights -of -way (Grover City Land Use Element, 1973).
Most urban development that has occurred in the City
has been single family residential construction (account-
ing for approximately 21% of the residential acreage,
and over 90% of the total housing stock.) Of the
remaining 6% of urban land use, various forms of medium
and high density residential development account for
approximately 2%, commercial enterprises contribute
approximately 2%, industrial uses (primarily service -
oriented) account for approximately 0.3%, and public
and quasi -public uses account for approximately 2%.
The type of low density urban form which occurs in Grover
City results in a fairly uncomplicated urban fire situa-
tion. The City is protected from fire by the Grover
City Fire Department, a volunteer organization numbering
22 volunteers, and headed by a professional fire chief.
2.37
The Fire Department operates from a single facility
located at 867 Ramona Avenue. The Fire Department's
inventory of rolling fire response equipment includes
the following;
1 1250 gpm Pumper
2 1000 gpm Pumpers
1 Rescue Panel Truck
1 Utility Vehicle
The Grover City Fire Department is capable of responding
to an emergency within the City limits within four
minutes.
The City's fire defenses are currently rated by the
Insurance Services Office as Class 6 for the entire
City area. The City Fire Department has entered into
mutual aid agreements with the City of Pismo Beach Fire .
Department and the City of Arroyo Grande Fire Department.
Mutual aid in fire protection is a reciprocal arrangement
in which several fire protection agencies share personnel
and equipment during emergency situations. Mutual aid
accomplishes an increase in fire protection capabilities
at minimum extra cost. However, mutual aid operations
usually lack the coordination and efficiency of operations
involving only one department.
(2) Potential Hazards
Potential hazards in Grover City are related primarily
to (1) the presence of the Southern Pacific Railroad,
(2) the deficiency of hydrants in some portions of the
City, and (3) the lack of multiple fire-fightingfacilities
in the City.
The Southern Pacific Railroad traverses the area in
generally a north -south direction, adjacent to the
western boundary of the City. The fire hazards associated
with its presence relate to the flammable and caustic
materials often transported in rail-motatted tank cars.
No major disasters of this type have occurred to date,
but the possibility of a future accident cannot be
precluded. The Grover City Fire Department, along with
other local agencies, would be relied upon for any fire
or chemical emergency a railroad accident might create.
Certain areas within the urban envelope of Grover City
have deficient fire hydrant coverage. Developed areas
that are more than 300-350 feet from the nearest fire
could request assistance from local fire departments,
including the Arroyo Grande Fire Department and the
City of Pismo Beach Fire Department. Both of these
agencies are lcoated in sufficient proximity to offer
assistance within minutes.
(3) Response Corridors/Evacuation Routes
hydrant appear on the Natural Hazards Map for Grover
Response corridors are defined as primary routes along
City. These areas include the following:
which emergency vehicles, including fire department
equipment, travel when responding to a fire, or similar
1.
Southern Pacific Railroad and Rockaway Avenue
emergency. Response corridors are usually primary or
2.
South Eighth Street and Longbranch Avenue
secondary roads that offer sufficient width for fire
3.
South Tenth Street and Seabright Avenue
vehicles. Roads chosen as response routes usually follow
(Grover City Elementary School)
the most direct paths to the various parts of the
4.
South Tenth Street and Ramona Avenue
community. However, response corridors are often the
S.
—Atlantic City -Avenue and -North Tenth Street
more attractive routes for general traffic flow - it
(Grover Heights Elementary School)
situation which sometimes results in traffic conjestion
6.
North Eleventh Street and Saratoga Avenue
and delays in emergency response.
7.
First Street and Newport Avenue
8.
Brighton Avenue and North Third Street
Primary response routes in Grover City include: lend
Deficient hydrant spacings force fire fighting personnel
to lay longer lengths of hose to deliver water to a fire.
Excessive hose lengths require more time for placement,
and result in lower pressures of water at the point of
delivery. Of special significance is the luck of hydrants
in the areas of Grover Heights Elementary School and
Grover City Elementary School. These facilities are
of a major critical nature both as school sites and as
potential evacuation centers during crisis situations.
Fire Departments in areas such as Grover City that operate
from a single station, run the risk of being isolated
from potential emergencies if critical transportation
links become jeopardized during periods of*extreme environ-
mental stress, or traffic congestion. However, Grover
City's location helps minimize the risk of such an
occurrence. In an emergency, the City Fire Department
2.38
Avenue, Ramona Avenue, Eighth Street, Tenth Street,
Railroad Drive, State Highway 1, Farroll Road, Brighton
Avenue, and Newport Avenue, Fourth Street, North 'Twelfth
Street, Thirteenth Street, Oak Park Blvd, Long Branch
Avenue, and Mentone Avenuc.
Evacuation routes as defined in Section VI, Emergency
Preparedness, often adhere to major response corridors
Such is the case in Grover City.
8. Atascadero
The built-up nature and varied landscape of the
a. Wildland Fire Hazards
Atascadero community necessitate the development of
an effective fire fighting agency. Out of this need,
Atascadero, an unincorporated community in north-
the Atascadero Fire Protection District was formed,
central San Luis Obispo County, ranks as the County's
and has been delegated the responsibility for fire
second largest urban area. The community has developed
protection in the community. The Fire District
primarily as a low density residential area with
operates from one station located on Lewis Drive in
supporting commercial land uses and service facilities.
Atascadero. The District is staffed by both pro -
Much of the residential development has occurred in the
fessional personnel and volunteers, and includes the
hilly portions of the area where flammable native brush
following:
and timber still remains. This trend has increased the
threat of wildland (or "rangeland") fire, and has
1 Professional Chief
actually brought urban and wildland fire together as a
2 Professional Captains
common safety consideration. To illustrate the nature
4 Professional Engineers
of this similarity, over 50% of the responses received
20 Volunteer Fire Fighters
by the Atascadero Fire Protection District involve
rangeland fires.
The District's inventory of rolling fire response
equipment includes the following:
Potentially, the most severe structural-wildland risk
areas are north of Traffic Way, and east of U.S. Highway
2 1000 gpm Pumpers (structural use)
101, and to a lesser extent, the area south of Pine
1 750 gpm Pumper (structural use)
Mountain and east of E1 Camino Real. Both of these
2 heavy 4-wheel-drive trucks (rangeland use)
locations are somewhat urbanized, and located near
1 Power Wagon (rangeland use)
flammable vegetation.
b. Urban Fire Risks
The District's fire defenses are currently rated by the
Insurance Services Office
as Class 5 for the entire
(1) General Setting
Atascadero Fire Protection District. Response to fire
The land use characteristics and the diversity of
emergencies in the community requires a maximum of five
minutes.
structural types make fire considerations more compli-
cated than would normally be expected in an unincorporated
(2) Potential hazards
setting. The community consists of a moderately -developed
commercial core along Traffic Way and El Camino
Potential urban fire hazards in the Atascadero area
Real.
The remaining flat areas have been developed as low
relate primarily to (1) lack basic fire safety
density residences. Much low density hillside develop -consideration
la
in the general layout and governing
ment has also occurred, the impacts of which are dis-
of the community, (t the pipelines and
cussed in the previous discussion. Atascadero is also
transmission lines that traverse the community and
community
the site of the Atascadero State Hospital, a state -operated
rangeland areas. (3) the presence of U.S. highway llll
mental health facility.
and the SOntherlr Pacific Railroad, and (4) the access
problems associated with operation from one fire station.
2.39
The major fire problem occurring in Atascadero is the
lack of appropriate planning. in the design and layout of
the primary and secondary streets that serve the area.
Existing street widths, especially when compounded
by on -street parking, are inadequate in several locations
for access by emergency equipment. In an emergency situa-
tion, valuable time would be lost in seeking alternative
routes to the particular point of emergency.
ficant environmental disruptions, failures have
been known to occur, resulting in pipeline rupture or
transmission line collapse. Failures are most likely to
be non -seismic in nature (see Section Iv C: Effects on
Utilities). They are more likely to be caused by faulty
pipes, accidental puncturing, or, in the case of power
lines, high winds.
The third set of potential hazard consideration
A second problem associated with planning consideration resemble those concerned with pipeline safety, and
concerns inadequate hydrant spacings in certain portions relate to the presence of U.S. Highway 101 and the
of the community. Many structures in the community are Southern Pacific Railroad in the area.
located on very large lots, and are often more than
500 feet from functioning fire hydrants. An effort to The Southern Pacific Railroad and U.S. Highway 101
promote closer hydrant spacings in the design phase of traverse the area in generally a north -south direction.
future proposed projects should be considered to alleviate The fire hazards associated with their presence relate
further -extensions -of -the -problems.. —Existing-locations, to -the -flammable -and -caustic -materials -often -trans=
particularly in the south end of the community and along ported in rail -mounted tank cars and trucks. No major
the west-northwest perimeter of the community, are disasters of this type have occurred to date, but the
currently impacted by inadequate hydrant spacings. possibility of a future accident cannot be precluded.
The Atascadero Fire Protection District, along with
As an unincorporated entity, Atascadero has no mechanism other local agencies, would be relied upon for any
to promote or require weed abatement for the purposes of fire or chemical emergency such an accident might create.
fire control. This results in the accumulation of plant
material in vacant lots, and near existing structures,
which raise the risks of fire to such areas. Incorporated
Cities throughout the County have the capability to
enforce such programs by requiring property owners to
abate local weeds voluntarily, or pay for the service in
the form of special tax levies. Weed abatement programs
are usually effective in lowering structural losses
during a fire situation.
The second set of potential fire hazards relate to the
presence of pipelines and electrical lines in the area.
The existence of infrastructure (oil pipelines, gas lines
and electrical transmission lines, in particular) can
increase an area's exposure to fire and explosion. Although
facilities of these types are designed to withstand signi-
2.40
The final hazard situation concerns those potential
access problems associated with operation from a single
station facility. Such stations run the risk of heing
isolated from potential emergencies if' critical trans-
portation links become jeopardized dtn•ing periods of
extreme environmental stress. A situation of this type
is possible in Atascadero. The community is effectively
bisected by Atascadero Creek, and access to each side
is governed by the passibility of bridges traversing
the creek. Although most bridges crossing the creek
are not susceptible to periodic floods, their perfor-
mance has never been tested during a Sturm producing a
flood of a 100-year frcquoncy. Fire protection in sucillur
communitios is often limi'ted to a central Facility
which serves the entire community. 1'hcrefote, this
problem is commonly encountered.
(3) Response Corridors/Evacuation Routes
Response corridors are defined as primary routes along
which emergency vehicles, including fire department
equipment, travel when responding to a fire, or similar
emergency. Response corridors are usually primary or
secondary roads that offer sufficient width for fire
vehicles. Roads chosen as response routes usually
follow the most direct paths to the various parts of the
community. However, response corridors are often the
more attractive routes for general traffic flow: a
situation which sometimes results in traffic conjestion
and delays in emergency response.
Primary response routes in the community include:
Traffic Way, California State Highway, Curbaril Avenue,
Atascadero Road, and U.S. Highway 101. Evacuation
routes as defined in Section VI, Emergency Preparedness,
often adhere to major response corridors. Such is the
case in Atascadero.
9. South Bay
a. Wildland Fire Hazards
The Southbay area does not face major wildland fire
threats due to its environmental setting. Vegetation
in the area is limited primarily to low growing grasses
and scattered shrubs, the characteristic vegetation of
disturbed Northcoastal Grasslands. Another fire -limiting
characteristic of this area is the cool, marine -influenced
climate. Temperature extremes do not occur very often,
nor does the relative humidity decline to critically -low,
fire hazardous levels.
b. Urban Fire Risks
(1) General Setting
The Southbay (Los Osos) area is an unincorporated,
primarily residential area that has undergone rapid growth
in recent years. Dining the period 1970-1974 Southbay
has increased in population from 3487 residents to 6589, 2.41
Housing units have nearly doubled during this period,
and now number approximately 2786.
The development of Southbay into a low density resi-
dential area necessitated the formation of the Southbay
Fire Department, the local agency responsible for fire
protection in the community.
The Southbay Fire Department operates from one facility
located on Baywood Heights Drive, and is staffed by
both professional personnel and volunteers, including
the following:
6 Salaried officers
4 Part-time officers and firefighters
12 Volunteer fire fighters
The Fire Department's inventory of rolling fire response
equipment includes the following:
1 1250 gpm Pumper
1 750 gpm Pumper
1 Ambulance
The Department's fire defenses are currently rated by
the Insurance Services Office as Class 7 for the
developed portions of the community and Class 9 for
those areas beyond present developments. The Southbay
department responds to approximately 75 alarms in a
year, 50% of which are structural in nature. Responses
to emergencies in the Southbay community require approxi-
mately four minutes.
(2) Potential Hazards
Potential fire related hazards in the Southbay area are
linked closely with the area's growth. Essentially,
the community's fire protective capabilities have not
kept pace.with the large increase in housing units and
population that has occurred in the last four years.
Street access and water supplies that were once adequate
are no longer so. This problem is difficult to localize
in a given area, however, it has been most keenly felt
vehicles. Roads chosen as response routes usually follow
in the vicinity of Santa Ysabel Road.
the most direct paths to the various parts of the community.
However, response corridors are often the more attractive
Another potential hazard arises from the large number
routes for general traffic flow: a situation which some -
of empty lots overgrown with weeds and accumulated debris.
times results in traffic congestion and delays in emergency
As an unincorporated entity, Southbay has no mechanism
response.
to promote or require weed abatement for the purposes
of fire control. This results in the accumulation of
Primary response routes in the community include: Santa
plant material in vacant lots, and near existing strut-
Ysabel Avenue, El Morro Avenue, Seventh Street, Ramona
tures, which raise the risks of fire to such areas.
Avenue, Ninth Street and Los Osos Valley Road. Evacuation
Incorporated cities throughout the County have the
routes as defined in Section VI, Emergency Preparedness
capability to enforce such programs by requiring property
often adhere to major response corridors. Such is the
owners to abate local weeds voluntarily, or paying for
case in Southbay.
the service in the form of special tax levies. Weed
abatement programs are usually effective in lower
10. Cayucos, Cambria, Nipomo, Oceano
-structural-losses-during-a-fire-situation-:- --
Introduction
The final hazard situation concerns those potential
access problems associated with operation from a single
The communities of Cayucos, Cambria, Nipomo and.Oceano
station facility. Such stations run the risk of being
share several basic characteristics with respect to fire
isolated from potential emergencies if critical trans-
hazards analysis. All three areas are unincorporated'
portation links become jeopardized during periods of
urban areas in San Luis Obispo County, and are primarily
extreme environmental stress, or traffic congestion.
residential in nature. Each community is served by
Although the community is not divided by a major stream,
volunteer fire departments that are somewhat limited
heavy flooding could conceivably render key response
in overall fire response capabilities. In view of these
routes useless, thereby necessitating detours in an
basic similarities they will be treated jointly. However,
emergency situation. Such detours would require extra
significant or unique characteristics will be discussed
response time, a factor critical during a fire or similar
relative to each location.
emergency.
a. Wildland Fire hazards
(3) Response Corridors/Evacuation Routes
Wildland fire hazards in the communities of Cayucos,
Response corridors are defined as primary routes along
Nipomo, and Oceano are not a major concern due to their
which emergency vehicles, including fire department
environmental setting. In these locations, the naturally -
equipment travel when responding to a fire, or similar
occurring vegetation is limited primarily to low -growing
emergency. Response corridors are usually primary or
grasses and shrubs that are characteristic of disturbed
secondary roads that offer sufficient width for fire
Northcoastal Grasslands, or it has been displaced by
2.42
urban uses and agriculture.
On the other hand, fires involving native vegetation play a
more significant role in the Cambria area. Cambria is
located in the mountainous area of the westernmost Santa
Lucia Mountains. Vegetation in the area falls within
the Evergreen Forest Classification, and is characterized
by the presence of large oaks, of various species, laurel,
madrone, and Monterey Pine. Trees in this plant community
often attain considerable height, and can interfere with
electrical transmission lines. A significant number of
fires in Cambria originate when tree limbs fall upon
electrical lines during periods of winds and stormy condi-
tions.
b. Urban Fire Hazards
(1) General Statement
Each community has been developed primarily as a low
density residential area, with some supportive commercial
enterprises, and little or no industrial concerns. Popu-
lations range from 2037 in Cayucos to 4683 in Nipomo.
The lack of intense, or particularly hazardous land uses
simplifies the urban fire situation in each area. The
fire protection need that does exist is currently provided
either by a small voluntary force in each community, or
through a contract with an agency such as the California
Division of Forestry. A listing of fire protective capa-
bilities, and Insurance Services Office classification is
contained in the following table:
2.43
Table 8
Fire Protective Resources
Cayucos, Cambria, Oceano, Nipomo
Voluntary ISO
Community Personnel Equipment Ranking
Cayucos 13 (1) 500 gpm pumper 8
(1) 200 gpm pumper
Cambria 20 (1) 750 gpm pumper 9
(1) 700 gpm pumper
4,
Oceano 20 2 750 gpm pumpers 7/9
Nipomo 2 paid personnel (1) 750 gpm pumper
provided through unranked
CDF
(2) Potential Hazards
The communities of Cayucos, Cambria, Oceano and Nipomo do
not possess the built-up areas or hazardous land uses that
normally create complicated fire defense situations.
Each community, in general, has responded to these situa-
tion by providing a minimum level of structural fire pro-
tection. The potential hazards that exist in each area
relate to the level of protection that has been provided.
For most emergencies in the communities the existing
protection would probably prove to be only marginally
effective or ineffective depending on the type and severity
of the emergency.
Providing additional fire protection in a community requires
expenditures of relatively large sums of money. Added
taxes and special district levees would be partially
offset by lowered insurance rates, but the net effect
would be an increase in cost -to the business operator
and property owner in the community. Presently, the
population does not seem to be willing to accept these
added costs, and is willing to function within the existing
level of protection.
T �I
Fire protection could be improved in the various
communities by providing more equipment, increasing water
supplies and adding paid, full-time positions to the
local department. Solely from the standpoint of fire
prevention, such groves seem warranted. However, the
economic base of the areas doesn't seem able to absorb
added levees to finance a more efficient fire depart-
ment. The solution, therefore, is to either accept
existing levels of protection or change the method by
which local fire protection is organized and financed.
Several methods exist which, if implemented, would
result in a reorganization that could possibly increase
protection at a net savings. A more detailed discussion
of these procedures will be included in the Policy
Section of the Public Safety Element.
3. Response Corridors/Evacuation Routes
Response corridors are defined as primary routes along
which emergency vehicles, including fire department
equipment travel when responding to a fire, or similar
emergency. Response corridors are usualily primary or
secondary roads that offer sufficient width for fire
vehicles. Roads chosen as response routes usually
follow the most direct paths to the various parts of
the community. However, response corridors are often
the more attractive routes for general traffic flow:
a situation which sometimes results in traffic conges-
tion and delays in emergency response.
Major response routes in each community are as follows:
Gayucos
State Highway One, C Street, Ash Street, and
Ocean Boulevard
2 .a.l
Cambria
State Highway One, Ardath Drive, Pineridge
Road, and Windsor Boulevard
Nipomo
Thompson Avenue, Teffet Road, and
Orchard Road
Oceano
- State Highway One, Paso Robles Street,
The Pike, Wilmar Avenue, and 22nd Street.
III. FLOOD HAZARDS ANALYSIS
significantly alter the hydrology of an area.
A. Introduction
For the purposes of this report, the flooding associated
with the 100-year storm will be of primary consideration.
The purpose of this report is to describe the potential
Such a storm has statistical likelihood of occurring once
for flooding and dam inundation in the County of San
in a hundred year time span, or a 1% chance of occurring
Luis Obispo and relate these findings to planning con-
in any given year. The 100-year flood can occur in any
siderations. The evaluation of flood hazards is, by
year or even more than once during a year, though such an
its nature, an approximating process that can be influenced
event is not "likely."
by several factors. In general, the areal extent of flood
hazards is delineated on the basis of estimated severity
The 100-year flood determination is becoming an accepted
of major storms and the performance of existing channels,
standard for flood protection by agencies involved in
either natural or man-made. The mapped portions of this
the assessment of flood risks. The Department of (lousing
study represent only approximated limits or flooding poten-
and Urban Development (HUD), in their issuance of flood
tial, and are based upon currently available data
insurance as part of the Flood Protection Disaster Act
derived from County, State, and Federal sources.
of 1974, has adopted the 100-year flood level as the
determinant of the flood plain area having a hazard poten-
8. General Conditions
tial requiring specified controls or protective measures.
The relationships of the Flood Protection Act of 1973
San Luis Obispo County is a large intra-state jurisdic-
to this study, as well as local planning, will be discussed
tion that comprises over 3,500 square miles of varying
at the conclusion of this report.
terrain in Central California. It stretches from the
San Joaquin Valley on the east to the Pacific Ocean on
C. Climate
its west boundary. Included within the boundaries of
San Luis Obispo County are a wide variety of climatic,
The climate of San Luis Obispo County resembles most of
topographic, and land -use factors that make the aspects
Southern California, with its relatively short rainy season
of flooding quite diverse throughout the County.
and drought -dominated periods extending from late Spring
through Autumn. More precisely, the climate of the County
The quality of life enjoyed by the residents along with
is Mediterranean. This type of climate is characterized
the productivity of agriculture, the County's largest
by three features: 1) rainfall of moderate amounts
industry, is closely linked to the availability of water.
concentrated in the winter seasons with summers being
However, the positive aspects inherent in its avail-
nearly or completely dry; 2) warm to hot summers and very
ability can become a serious liability during a flooding
mild winters•; and 3) a high percentage of sunshine
situation. To protect certain low-lying areas prone to
throughout the year, particularly during summer. Snowfall
periodic flooding, protective measures including dams,
as a factor in the Mediterranean climate is of little
levees, and enlarged channel ways, have been constructed
significance in that it is entirely absent from the valley
to help minimize the risks to life and property. The
floor, and is generally light in the mountain areas
adequacy of these facilities is dependent upon the capacity
except at extreme altitudes.
to which they were designed, relative to the site of
flood being considered, as well as the growth that has
The mean annual precipitation in San Luis Obispo County
taken place in adjacent areas. Growth, or more precisely,
varies, depending upon relative position of surrounding
the changes in surface permeabilities and slopes can
topographic features. County -wide, precipitation varies
2.45
from a low of approximately 5 inches per year in the
Temblor Range and the Cuyama Valley to means of 30
inches per year in the Santa Lucia Mountains.
The table below presents the 32-year mean seasonal
precipitation for regions within San Luis Obispo
County. The values are based upon precipitation records
for several stations within each region kept over the
past 30-50 years.
Table 9
Mean Seasonal Precipitation
Location
San —Luis Obispo _ --
(Poly)
Paso Robles
Atascadero (Mutual
Water Co.)
Templeton
Shandon (Union
Oil Company)
Avila Beach (Union
Oil Company)
Santa Margarita (Union
Oil Company)
Hearst Ranch
(San Simeon)
Simmler (State
Division of Hwys)
Cambria (State
Division of Hwys)
Years of
Record
102
84
54
46
39
40
32
35
35
31
32-Year
Mean
21.68
14.78
17.49
19.19
9.62
16.78
Years of
32-Year
Location
Record
Mean
Arroyo Grande
(Police Department)
33
15.60
Los Osos
(Bender)
18
18.13
Nipomo (State
Division of Forestry)
13
13.44
Oceano
(C.S.A. 013)
13
13.11
Baywood Park
(C.S.A. 09)
6
16.00
Whale Rock Reservoir
(Cottontail Creek)
3
--
Based on the preceding table, it appears the higher elevation
areas in the County absorb most of the rainfall, and thus, are
exposed to greater risk of flooding. That observation,
however, ignores the concept of watershed, an element cri-
tical in determining the likelihood and extent of flooding.
The precipitation that falls in the upper elevations of
a watershed collects and is conveyed through streams and
river systems to the sea or to low-lying lakes and ground-
water basins. The accumulation of water that occurs in
the lower elevation areas of the County creates the most
damaging episodes of widespread flooding.
20.39 D. Streams
25.59 The major streams in the County, both from the standpoint
of average flows, and flooding potential, include the
Salinas River, Santa Maria-Cuyuma River System, Nacimiento
8.52 River, San Luis Obispo Creek, Arroyo Grande Creek, Morro
Creek, and Huer Huero Creek. All of these river systems
18.90 include numerous smaller tributaries that contribute to
the overall drainage in the County. Each river system
demonstrates a different set of physical characteristics
1.46
and land -use patterns that influence the flooding poten-
tial.
The Salinas River originates in the high country of .the
Santa Lucia Mountains near the community of Santa Margarita
It drains over 500 square miles of San Luis Obispo
County before exiting the County near San Miguel, the
County's major streamcourse. The river also creates
the most extensive floodplain in terms.of acreages
inundated, however, much of the resultant floodplain
is contained within the fairly well-defined stream bed.
The Santa Maria-Cu ama River System is another major
drainage network in t e central coastal area. The river
system originates in the Los Padres National Forest area
in Ventura County, and flows in a generally westward
direction, emptying into the sea near Santa Maria.
Together, the two rivers define the .south boundary of San
Luis Obispo County. The floodplain associated with the
system varies greatly in width, sometimes exceeding
one mile. However, much like the Salinas River, the Santa
Maria-Cuyama River System floods mostly those areas lying
within the well defined floodplain.
The Nacimiento River drains approximately 3SO square
miles of northern San Luis Obispo County, and is one of
the major tributaries to the Salinas River. Much of the
river has been obliterated by Nacimiento Reservoir built
in 1957. The "buffering" capacity created by the con-
struction of the dam has mitigated much of the downstream
flood potential associated with the river.
San Luis Obispo Creek originates in the western slopes of
the western slopes of the Santa Lucia Range, at an elevation
of approximately 2,200. The Creek flows generally in a south-
west direction through the City of San Luis Obispo, and is
joined by its major tributary, Stenner Creek, in the west
portion of downtown San Luis Obispo. The total drainage area
for the entire creek basin is approximately 83 sq. miles, an
area which may seem less significant than the other rivers and
drainage basins previously discussed. However, the hydrology
2.47
of the San Luis Obispo Creek basin and the land use adja-
cent to the creek in the City combine to form a signifi-
cant flood hazard. This particular drainage system has
been the subject of extensive analysis, including a 1974
report published by the U.S. Army Corps of Engineers.
Arroyo Grande Creek drains approximately 120 square
miles of southwestern San Luis Obispo County. It originates
in the southerly portion of the Santa Lucia Range, and
drains generally southwestward, through the City of
Arroyo Grande. The flood potential of Arroyo Grande
Creek has largely been mitigated by the construction of
Lake Lopez Dam.
Morro Creek originates in the Cerro Alto area of the
Santa Lucia Mountains, and drains in a westward direction,
eventually emptying into Morro Bay. Morro Creek drains
approximately 24 square miles, and essentially bisects
the City of Morro Bay. Most flooding in the Morro Bay
area is associated with this particular stream.
Huer Huero Creek drains approximately 150 square miles
of generally flat terrain in the Paso Robles area.
Most major flooding in the vicinity of Paso Robles is
caused by this drainage, and the Salinas River drainage.
E. Historic Floods
San Luis Obispo County has been damaged by severe, widespread
flooding numerous times.during its history. Early
records indicate that flooding destroyed homesteads and
livestock and polluted local wells. The loss of life
and property to flooding disasters mounted as more people
moved into the area, building homes and other capital
investments either in, or adjacent to, the flood plain.
The escalating dollar costs of flooding were clearly
illustrated during the 1969 flood. When property damages
totaled approximately $5,000,000. Economic vulnerabilities
continue to increase as the County grows in both popula-
tion and overall worth.
1. January -February, 1969
The floods of January -February, 1969, were the most
damaging floods of record in San Luis Obispo County.
On January 14 a three day storm began which produced
approximately 2 inches of rain in the San Luis Obispo
area. That storm, though considered a sizeable event,
produced no flooding problems because rainfall inten-
sities were low and a large percentage of the precipi-
tation penetrated the soil. Three days subsequent, a
series of warm rains moved in from the southwest.
This began an eight -day period of nearly continuous
medium and high intensity rainfall which totaled 12.01
inches in Paso Robles and 21.80 inches in San Luis Obispo.
Rainfall essentially ceased for the first half of
February, _allowing_for.some_relief_and._recovery
__from
the damages of the January flood. However, another
storm struck the -area the evening of Pebruary 21 and
continued with little abatement for six days, deposit-
ing an additional 5.6 inches of rainfall in the Paso
Robles area and 9.5 inches in the vicinity of San Luis
Obispo.
The 1969 floods created serious hardships for residents
throughout the County. The U.S. Army Corps of Engineers,
in their publication "Report on Floods of January
and February, 1969 in Southern California" offer this
account of the damages caused by the two high water
episodes:
"The most severe damages to urban property occurred in
the City of San Luis Obispo, where the San Luis Obispo
Creek channel became clogged with debris and flow in the
channel overtopped the channel banks and moved down the
main streets of the city. Massive mobilization efforts
during and after the January flood by the City of San
Luis Obispo and the Corps of Engineers prevented addi-
tional damages to urban property during the February
flood. Severe damages were sustained by streets,
2.48
highways, and utilities throughout the County. The
Water -supply system of Cambria was damaged in the
floods and large parts of the town were without elec-
tricity; residents were advised to drink only boiled
water because of the possibility that the local water
supply might be contaminated. The destruction and damge
of sewerlines and sewage -treatment plants at many loca-
tions posed a threat to the lives and health of many
residents. The sewage -treatment plants at Morro Bay,
Avila Beach, and Pismo Beach were inundated by both
floods. Debris and raw sewage piled up on the beaches
and carried in the streams posed serious threats to
health until emergency cleanup operations were completed."
A detailed summary of the flood damages from the
January and February 1969 flood also appeared in the
previously described U.S. Corps of Engineers report,
and is -included here:
J.
Table 10
Flood Damage Summary, 1969
San Luis Obispo County
Residential $ 289,000 $ 8,600
Business and
industrial (including
vehicles)
826,500
Agricultural
594,600
Highways and bridges
1,047,600
Utilities
315,100
Public
308,600
Flood -control, irriga-
tion, and water -
reclamation facilities
Railroad
Beaches, parks, recre-
ational facilities,
harbors
Land (undeveloped)
Military (Vandenburg
Air Force Base)
Stream channels requir-
ing clearing and
restoration 767,400
33,700
119,100
28,500
103,800
105,000
451,100
$ 297,600
860,200
713,700
1,076,100
418,900
413,600
1,218,500
Total $4,148,000 $849,800 $4,998,600
*Included in damages to public property
2. January, 1973
The flood of January, 1973 was the most devastating flood
ever recorded for the San Luis Obispo Creek drainage area.
Much like the floods of 1969, the 1973 disaster was of
the general winter type, producing a ten -.hour period of
unusually heavy rainfall. San Luis Obispo Creek, and its
tributary, Stenner Creek, overtopped their banks and
inundated wide areas of downtown San Luis Obispo. Damage
figures exceeded the 1.5 million dollar level that was
incurred during the flood disaster of 1969.
2.49
F. existing Flood Hazards
Flooding can create several types and levels of hazards
to residents in an area. The most direct threat relates
to the hazard to human life created by the sheer force
and volume of water that can accompany periods of heavy
runoff. In general, a flood depth of 3 feet and a
velocity of 3 feet per second is considered a major
threat to human safety.
A second level of hazard is concerned with the effects
of flood waters on property. Most dollar losses
associated with flooding are incurred through damage
to both public and private structures and improvements.
A third level of hazard associated with flooding is
impairment of response capabilities by emergency per-
sonnel and of communication -transportation networks
necessary during an environmental disaster such as a
major flood. Bridges that traverse flood prone streams
are a major concern. By obstructing downstream flows,
bridges create a damming effect on large volumes of
floodwaters. These floodwaters can, in turn, exert
significant amounts of hydrostatic stress on the bridge
supports in direct contact with the surging floodwaters.
Stresses of this type can occasionally be of sufficient
magnitude to cause structural damage or total failure of
a bridge facility. Bridges across key routes become
even more critical during emergencies such as major
floods. An important response route rendered unusable
by heavy runoff could seriously jeopardize an agency's
ability to respond in the most efficient manner.
100-year flood plains described in the folloding pages
appear on the Natural Hazards Maps prepared for each
City and unincorporated planning area in the County.
All maps and flood -related conclusions were developed
from existing information for Federal. State, and
County sources. These delineations indicate only the
general extent of flood plains and are not adequate for
specific hazard lands administration purposes such as site -
planning, zoning application or building regulations
enforcement. Precise mapping based on engineering surveys
by qualified personnel will be necessary to definitively
fix the boundaries of the 100-year floodplain.
1. City of San Luis Obispo
The City of San Luis Obispo would be exposed to major
flooding in the event of a 100-year flood. Flooding
would occur throughout the length of San Luis Obispo
Creek and its major tributary, Stenner Creek, Brizziolari
Creek and Prefumo Creek. Studies compiled by the U.S.
Army Corps of Engineers indicate the resultant flood -
plan would be particularly wide in the areas of Santa
Rosa Street, and Broad Street-, as well as Prado Road
and Laguna Lake to the south:
The floodplain in the San Luis Obispo area has been
influenced by surrounding land use changes. The area's
development has resulted in increased runoff in the
area, and the emplacement of flow obstructions (bridges
and culverts) across the streams in the area. Infor-
mation generated by the Corps of Engineers indicates
that several of these obstructions would be submerged
---in-a-flood-of-a --- 100- year -magnitude.- The -following -
table, taken from the 1974 Corps of Engineers Flood
Plain Information report for San Luis Obispo Creek
lists these various obstructions, as well as estimated
flood elevations in each respective location:
Table 11
Elevation Data for 100-year
Flood Along San Luis Obispo Creek
and Tributaries
Low Chord 100-Year Flood
Identification Elevation Elevation
SAN LUIS OBISPO CREEK:
Harford-Avila Rd.
22.0
10'.2
San Luis Bay Dr.
28.7
20.6
Ontario Road
31.0
27.7
U.S. 101
33.0
31.4
San Luis Bay Dr.
37.0
41.5
Abandoned Farm Rd.
34.9
43.6
Private Road
45.0
48.9
Private Road
63.0
67.7
Private Road
65.0
71.0
2-50
Low -Chord
100-year
Identification
Elevation
Flood Elevation
SAN LUIS OBISPO CREEK:
South Higuera St.
80.0
85.3
Abandoned Hwy.
86.8
90.7
Prado Road
133.0
133.0
Elks Lane
142.0
145.0
Madonna Road
159.0
155.1
Bianci Lane
163.5
169.2
Marsh St.
167.0
175.5
Nipomo St.
187.3
192.5
Broad St.
195.9
192.9
Wood Footbridge
193.9
193.0
Concrete Footbridge
201.8
196.0
Undercity Culvert Outlet
202.0
202.0
Undercity Culvert Inlet
212.0
218.8
Marsh St.
216.5
218.8
Santa Rosa Street
219.7
224.0
Toro- Street- - ---
- 226.0
- ---231-.0
Johnson Avenue
23S.6
234.2
S.P.R.R.
249.0
241.2
California Blvd.
249.5
253.0
Andrews St.
272.7
276.0
U.S. 101
306.4
318.8
STENNER CREEK:
Nipomo St.
180.7
187.5
U.S. 101
183.3
199.1
Broad St.
194.1
199.1
Chorro St.
191.9
199.1
Santa Rosa St:
226.0
230.5
Murray St.
231.3
235.2
Foothill Blvd.
242.6
254.9
Cal Poly Access Rd.
270.8
279.0
West Mt. Bishop Rd.
313.6
312.0
Stenner Rd.
319.0
320.4
PERFUMO CREEK:
U.S. 101 102.0 107.0
U.S. 101 offramp 103.7 109.8
Calle Joaquin 105.6 109.9
Madonna Road 124.9 126.0
Low Chord 100-year
4, City of Pismo Beach
Identification Elevation Flood Elevation
BRIZZIOLARI CREEK:
Flooding in the Pismo Beach area occurs primarily in the
Agricultural
Agricultural Rd. 285.0 283.2
low-lying areas to the east of the City. Much of this area
285 8 285 5
is comprised by Pismo Marsh, and thereby does not
N. Perimeter Rd. 281.8 285.5
constitute a major threat. A potential hazard could
Unnamed Culvert 281.1 286.0
294.1
result, however, if the City s sewage disposal plant was
Campus Footbridge 303.1
damaged by flooding. A similar event occurred during the
Campus Way 303.5 308.4
1969 flood, and created a substantial secondary health
Unnamed Culvert 314.7 319.0
hazard.
Unnamed Culvert 328.5 335.8
5. City of Arroyo Grande
Flooding in the City of Arroyo Grande is confined to
2. City of Morro Bay
the Arroyo Grande Creek area and does not constitute a
Flooding in the City of Morro Bay during a 100-year storm
major hazard. However, flooding at 100-year levels could
would probably occur along Morro Creek and Little Morro
hinder response efforts if certain routes and key
Creek. The flooding itself would be primarily limited to
bridges were rendered unusable by high water levels.
the creek area, and would not extend into areas away
6. Grover City
from the defined stream bed. A potential hazard could
develop, however, if high water volumes rendered the
Flooding in the Grover City area is confined to the
State Highway 1 bridge unusable. This facility is criti-
beach area, and a well-defined corridor south of U.S.
cal to emergency response in the northern part of the
Highway 101, and does not present a significant hazard.
City. Unnamed Creek is also a source of potential
flooding. Flood waters from Unnamed Creek have poten-
7, Atascadero
tial for overflowing the stream bed and blocking passage
The community of Atascadero is located adjacent to the
on North Main Street.
Salinas River, and is exposed to a minimal level of
flood hazard from heavy runoff along that stream. Since
3. City of E1 Paso de Robles
most flooding would be restricted to the defined
The City of E1 Paso de Robles would be affected most
river area, existing hazards relate more to potential
by flooding along the Salinas River. A 100-year flood
access and response difficulties during high water l\ 1
on the Salinas River would separate the eastern part of
periods. _
the City from the main western portion. While fire pro-
tection is provided on both sides of the River, water
8. South Bay
and sewer services could be impaired on the east side in
The community of South Bay is confronted with no major
the event of a major flood. Other flood prone areas
flood -related hazards.
exist along Mustard Creek Road, 12th Street, Pacific
Avenue, 4th Street, and Paso Robles Bouelvard.
9. Cayucos
Response efforts could be affected by estimated flood
Since flooding in the Cayucos area is confined to the
heights in the City.
streams and washes of the area, the area faces no major
flooding hazards.
2.51
10. Cambria
100-year flooding in the Cambria area is confined to
the Santa Rosa Creek, thereby eliminating major
flooding problems associated with overland flow.
However, even restricted flooding in the community
could significantly hinder emergency response
efforts.
11. Nipomo
Flooding in the community of Nipomo occurs primarily
along Nipomo Creek, Deleissiques Creek, and an
unnamed creek system flowing basically in the align-
ment of Tefft Street. Anticipated overland flows are
fairly well restricted to the creek areas; and the
remaining potential hazards are primarily related to
street access and bridge adequacy in the area.
12. Oceano
The community of Oceano is not confronted with major
flood hazards.
G. Hazards From Dam Failure
Section 8589.5 of the Government Code, which became
law in 1973; requires all dam owners to submit to
the State Office of Emergency Services (OES), maps
showing areas that would be inundated given an instan-
taneous collapse of their respective dams. Large
dams are categorized with nuclear reactors, power inter -
tie systems, and plants manufacturing explosives as
structures whose continued functioning is critical, or
whose failure might be catastrophic. Although this
type of catastrope is highly unlikely, the nature of
the hazard is such that it should be considered.
The collapse of a dam, an event of unforeseen severity,
would create an inundation several magnitudes greater
in area than a flood caused by heavy rains. Records
from the 1928 failure of the St. Francis Dam in Los
Angeles County (capacity 32,000 acre-feet) describe
2•S2
a flood flow of
500,000 cubic feet
per second,
and a
"wall" of water
over 100 feet high
in the confining
canyon (Report
of Commission 1928).
It should
be
stressed, however,
that none of the
dams affecting
the study area
should fail, based upon current
evidence.
Pertinent characteristics
of the large dams and.reser-
voirs in the study
area are summarized
as follows:
Capacity
Type of
Name
Owner (acre-feet)
Facility
Atascadero*
S.L.O. County
250
Earth
Eagle Ranch
Helen Smith
300
Earth
Hartzell
W.W. Hartzell
300
Earth -rock
Las Tablas
Creek
Paul R. Hackstedde
180
Earth
Lopez*
S.L.O. County
Flood Control
51,000
Earth
Nacimiento*
Monterey County
Flood Control
350,000
Earth
Righetti*
Ernest Righetti
564
Earth
Salinas Dam*
Corps of Engineers
26,000 Variable
Arch
San Marcos
H.E. Blythe
325
Earth
Terminal*
S.L.O. County
Flood Control
844
Earth
Twitchell*
Bureau of
Reclamation
240,000
Earth
Whale Rock*
State Department
of Finance
40,000
Earth
*Inundation map available
Of the dams listed in the preceeding table, Whale Rock
Reservoir, Righetti Reservoir and Lopez Reservoir have
the greatest hazard potential in the County. The inun-
dation maps for the remaining dams indicate (1) no appre-
ciable flow beyond existing stream boundaries, (2) flooding
in areas away from human settlement, or (3) flooding in
areas outside San Luis Obispo County.
Whale Rock Reservoir, with a capacity of 40,000 acre-feet,
is located in the hills above the community of Cayucos.
The level of damage in Cayucos to be anticipated given
the complete failure of Whale Rock Reservoir at full
capacity would be enormous. Approximately 15 minutes
would be required for the initial flood wave to reach
the sea, and, in that time, approximately one-third of
Cayucos would be essentially destroyed. When compared to
a natural flood, the time of the actual disaster would
be brief. The velocity of flow during this time and
sheer volume of the inundation wave would cause signifi-
cant levels of destruction.
An inundation of Lopez Reservoir at maximum volume
(51,000 acre-feet) would cause widespread inundation in
the Arroyo Grande Valley area. Since the developed
areas of the Valley are located primarily on flat plain
drained by Arroyo Grande Creek, the inundation of these
areas is expected to be slow. This relatively slow
raising of the water level would help mitigate much of
the impact of dam failure because it would allow for
evacuation and temporary damming of exposed property.
Righetti Reservoir is a privately -owned facility with
a capacity of approximately 564 acre-feet. Given a
complete failure at full capacity, an inundation wave,
ranging in width from 200 feet to 1000 feet would
closely parallel Corral de Piedra Creek. Such an
inundation would have neither the volume nor the
destructive force which can be expected in the event of
dam failures at either Whale Rock Reservoir or Lopez
Reservoir.
Since few inundation disasters have occurred in recent
times, the ability of structures to withstand the expected
sources of a flood surge is not well understood. Current
procedures for human safety define evacuation, as was
seen during the Van Norman Dam experience, as the only
safe solution when the threat of inundation is imminent.
2 •53
Dam failures and subsequent inundations should be
considered as events that can occur, but are very unlikely
to occur. Studies concerned with the potential impacts
of failure, including those referenced in this analysis,
are evacuation tools to be used during the implementation
of Civil Defense procedures. No assumptions or conclu-
sions regarding dam safety are contained in such studies.
H. Relationships Between Local Planning and
Federal Flood Insurance
San Luis Obispo County has experienced severe episodes
of widespread flooding many times throughout its
history. Past floods have cost the lives of many indi-
viduals, as well as dollar losses that amount to many
millions of dollars. Like much of the nation, San
Luis Obispo County faces an ever-increasing potential
economic loss due to flooding.
Early man did not face as great a peril to occasional
flooding as does his modern successor. Village remains,
in many cases, indicate he respected the river for
both its life-giving water, and its power, and seldom
were their villages inundated by onrushing flood waters.
However, in the centuries of development since those
early times, man's relationship with local streams has
changed. Pressures to grow and expand have made the
floodplains very attractive for development. Man found
that by building in the flat floodplains he could do
so cheaply. He also found that needed water could
be found by tapping aquifers lying below the floodplains.
Thus, the floodplains and areas near them became the
focal points for developments of the cities, towns, and
agricultural centers that exist today.
Early recognition of the hazards associated with flooding
brought efforts to minimize the danger. Since floods
were caused by rivers and creeks, the first apparent
solution involved controlling the rivers themselves.
Dikes, levees and dams, made possible by grants, bonds
and other capital outlays insulated several areas from
flood hazards:
However, the expense of flood -control facilities make
complete protection of areas such as San Luis Obispo
County a very costly proposition. The Federal Govern-
ment, alarmed by rising damage claims due to flooding,
initiated another approach to flood control with the
passage of the Flood Disaster Protection Act of 1973.
That act proposed another technique of flood protection.
Instead of "keeping the flood from the people" the
intent of the measure sought to "keep the people from
the flood." By relying on the existing financial
regulating capabilities of Federal Government, the
administering agency, namely the Department of Housing
and Urban Development (HUD), stated that no federally -
related or federally -insured funds would be available
for .new construction in areas designated "special
flood hazards", unless specified flood -proofing measures
were applied. The Act also allowed existing structures
located in designated flood hazard areas to be insured
for flood damages at a subsidized rate.
Communities were given- until July 1, 1975 to participate
in the Federal program. On that date, the prohibition
on federal financial assistance became effective. Prior
to that date, it was necessary for HUD to catalog those
areas in the country exhibiting the potential for flooding.
A massive effort was begun in 1973 and by the deadline,
most incorporated areas in the Country were mapped on a
preliminary basis. Included among them were all Cities
and communities in the County of San Luis Obispo.
z• 5a
C O r
IV. GEOLOGIC HAZARDS ANALYSIS
The Nacimiento fault is seismically active. Data
is inadequate to determine the potential for future
A. General Statement
ground rupture.
Geologic and seismic hazards have been analyzed for
The Riconada fault is seismically active, but pro -
the County generally and for each of the Cities in
bably not the site of ground rupture in the
the County as a part of the Seismic Safety Element
near future. Data is inconclusive on the latter
for each of these jurisdictions. To avoid unnecessary
point, and additional studies would be advisable.
duplication, the major conclusion of these analyses
The Offshore fault is seismically active, but avail -
are summarized below for the County, and for those
able marine geophysical data indicate future surface
Cities or groupings of Cities that have adopted ele-
rupture is very improbable.
ments. Summaries for unincorporated areas such as
Cambria and omo are extracted from data developed
The San Juan, La Panza, East Huasna, West Huasna,
for the County Seismic
y Seismic Safety Element. In addition
Edna, Indian Knob, San Miguelito, and Edna extended (?)
to the major conclusions regarding geological hazards,
faults are probably inactive.
the interactions of these hazards with certain major
types of facilities such as dams and utilities are
Ground Shaking
discussed in succeeding sections.
The primary source of strong ground shaking in the
County is expected to be the San Andreas fault. An
B. Geologic Hazards
earthquake of Richter magnitude 8.0 to 8.5 is expected
in the near future.
1. San Luis Obispo County
The Nacimiento fault is considered a secondary source
Specific conclusions regarding seismic and geologic
of strong shaking that could modify the zonation in
hazards from the Seismic Safety Element of the County
the northwestern part of the County. Available data
are summarized below. References are to the.Plates
indicate a very long recurrence interval (1400 years)
and Tables included in that Element.
for this event, but the occurrence of a magnitude
6.0 event in the instrumental record suggests an
Active Faulting
earthquake of this magnitude should he considered.
The states of activity of the major faults
Shaking from earthquakes expected on the Rinconada
in the County have been evaluated using avail-
and Offshore faults would not significantly modify
able detailed mapping supplemented by local
the severity of shaking expected from the San Andreas
field examinations and aerial photo study.
fault.
The evaluation has been made in the context
of definitions and procedures established for
Based on the San Andreas and Nacimiento faults as
the Alquist-Priolo Act.
sources of shaking, the County is divided into 4
zones based on distance to the causative fault, within
The San Andreas fault is active, and is expected
which 5 basic rock and soil conditions may he present.
to be the source of a magnitude 8.0-8.5 earth-
The combination of these two controlling parameters
quake in the near future. This earthquake would
results in a maximum of 20 zones based on both dis-
be accompanied by 20-30 feet of ground displace-
tance and rock type.
ment.
2. 55
The general characteristics of ground shaking in
each zone and the reference to the response spectra
are given in Table 15 of the Element.
Secondary Hazards
Areas susceptible to damaging rates of settlement
identified in the course of the investigation are
limited primarily to recently deposited alluvium
as in the channels of active streams and some bay
or ponded mud deposits as at Morro Bay or Lake
Laguna. These areas are generally unsuitable for
construction in their natural state because of
hazards other than seismic (e.g. flooding), and
considerable modification would be required before
occupancy would be safe.
An unusual area of rising ground is.present near
Edna. Preliminary work by the California Division
of Mines and Geology indicates that settlement is
not involved, but the nature of the rising ground
is as yet unknown.
The evaluation of liquefaction potential in a
deposit requires detailed information on the
engineering properties of the material as well as
the shaking characteristics of the earthquake.
The latter are included herein for use by the
soils engineer in evaluating the liquefaction
potential of a site utilizing the detailed
engineering data acquired during the site inves-
tigation.
A generalized guide to the liquefaction potential
of certain materials is as follows:
2 .56
Material
Rock'
Terrace deposits, etc
Recent alluvium
Liquefaction
Potential
Very Low
Low to Moderate
Moderate to High
Units on Plates
IA & 2A
a, b, c,
d
e, x, (in part)
Landslide risk categories are delineated on Plate 2A
for the coastal port op of the County, and on Plate IA
for the central and eastern parts. The categories
are based on empirical relationships between landslides
known in areas of detailed mapping and controlling
parameters such as rock materials, rainfall and slope.
Tsunamis and Seiches
Records of tsunamis along the County's coastline in
the past indices ate that those to be expected in the
future should not exceed the tidal range. A hazard
would exist if a tsuanami and high tide should occur
in phase.
True seismic Seiches are not considered as constituting
a significant hazard in San Luis Obispo County.
2. City of San Luis Obispo
Conclusions regarding seismic and geologic hazards are
summarized from the Seismic Safety Element of the City of �.
San Luis Obispo as follows:
Active Faulting
No active or potentially active faults, as defined
by the State Geologist and the State Mining and Geology
Board, are known to be present in, or in the near
vicinity of, the City.
Ground Shaking
The appraisal of slope stability has identified five
The primary source of strong ground shaking in the
zones of relative risk. The alluvial valleys
(Zones R and RL) are considered as having negligible
City is expected to be the San Andreas fault. An
risk; the terrace deposits and Paso Robles Formation
earthquake of Richter magnitude 8.0 to 8.5 is
(Zones Q and P) as having low risk; Cretaceous
expected in the near future.
rocks (Zone K) as having moderate risk; Tertiary
Shaking from earthquakes expected on the Rinconada
rocks (Zone T) as having high risk; and Franciscan
and Offshore faults would not significantly modify
rocks (Zone F) as having very high risk. These
the severity of shaking expected from the San Andreas
zones and known landslides are delineated on the
fault.
Seismic Zones Map.
The City is located in Zone 1 of the County Seismic
Tsunamis and Seiches
Safety Element. The characteristics of expected
shaking for six microzones, based on variations in
Tsunamis, or "tidal waves", are limited to the
rock/soil type, are summarized in Table 1 and
coastline of the County, and are not a hazard in
Figures 1 through 3 of the Element.
the City.
Secondary Ilazards
True seismic seiches are not considered as constituting
a significant hazard in the City.
Areas subject to liquefaction are rated as high* in
areas of well stratified lake deposits (Zone RL), with
3. Morro Bay, South Bay, Cayucos and Vicinity
a high water table; as high in poorly consolidated
alluvial deposits (Zone R) where limited groundwater
Conclusions regarding seismic and geologic hazards are
data suggests levels less than 30 feet below the
summarized from the Seismic Safety Element of the City of
surface; and as low to moderate in terrace deposits
Morro Bay for that City, and from County Element for
and the Paso Robles Formation (Zones P and Q).
the other areas.
Rock materials (Zones F, K, and T) are considered
to have a very low to essentially non-existent
Active Faulting
potential for liquefaction. These zones are delineated
on the Seismic Zones Map accompanying the Element.
No active or potentially active faults, as defined
by the State Geologist and the State Mining and
Liquefaction is not expected to be widespread,
Geology Board, are known to be present in, or in
but may occur locally, particularly in Zones R and
the near vicinity of, this area.
RL. Detailed soils engineering and geologic
Ground Shaking
investigations will be necessary to further evaluate
the potential for liquefaction, and to further
The primary source of strong ground shaking in the
define affected areas.
area is expected to be the San Andreas fault. An
No areas of expected significant settlement have
earthquake of Richter magnitude 8.0 to 8.5 is
been identified outside of areas identified as
expected in the near future.
potentially subject to liquefaction.
Shaking from the earthquakes expected on the Nacimiento
or the Rinconada and Offshore faults would not
2. 57
significantly modify the severity of shaking
expected from the San Andreas fault except near
Cayucos where a slightly higher level of shaking
is expected as.a result of earthquakes expected
from the Nacimiento fault at risk levels appli-
cable to critical facilities.
The area is located in Zone L (Partially in
Zone 2 for critical facilities) of the County
Seismic Safety Element. The characteristics of
expected shaking for microzones, based on vari-
ations of rock/soil type, are summarized on
Plate I of the Morro Bay Element and on Plate
2A of the County Element. The characteristics of
the ground shaking are described in detail on
figures and in tables in each of these Elements.
Secondary Hazards
The potential for liquefaction and significant
settlement is considered very high on the bay muds
(Seismic Zone "X") in and adjacent to Morro Bay;
high on landslide deposits (delineated on plates);
moderate to high on Recent alluvium (Seismic Zone
$fell),; low to moderate on terrace deposits and
older sand dunes (Seismic Zone "d"); low on
active sand dunes (Seismic Zone "x"); and, very
low on Franciscan bedrock (Seismic Zone "b").
These zones are delineated in varying detail on
Plate 1 of the Morro Bay Element and Plate 2A
of the County Element.
The areas of higher risk for liquefaction and
settlement are generally unsuitable for develop-
ment because of other hazards such as flooding,
tidal inundation or landsliding.
The appraisal of slope stability is displayed
on Plate I of the Morro Bay Element and Plate 2B
of the County Element. Two basic categories
are present: negligible to low risk (categories
0 and 1) in the lowlands and on the terraces; and
high risk (Category 4) on the Franciscan bedrock.
2.58
Known landslides are delineated where they
have been mapped as near Morro Bay, but critical
areas near Cayucos and Whale Rock Reservoir have
not been mapped.
Further delineation of landslides in this area
is necessary to adequately evaluate risks to
Cayucos either directly or from flooding due to
landsliding into Whale Rock Reservoir.
Tsunamis and Seiches
Tsunamis, or "tidal waves", are potentially dan-
gerous along the beach and in Morro Bay if the
tsunami and high tide should occur in phase.
Considerations and response recommended by the
State Division' of Mines and Geology are included
in the Morro Bay Seismic Safety Element.
True seismic Seiches are not considered a hazard
in this area, but traveling waves generated by
possible landsliding into Whale Rock Reservoir,
as noted above, may constitute a significant
hazard.
4. Paso Robles, Atascadero and Vicinity
Conclusions regarding seismic and geologic hazards in
this area are summarized from the Seismic Safety Elements
of the City of Paso Robles and the County Element.
Active Faulting
The Rinconada and Jolon faults are considered
potentially active by the California Division of
Mines and Geology. However, review of available
information and field examinations conducted for
the Elements noted above indicate that neither of
these faults is active with respect to ground
rupture.
Ground Shaking
The primary source of strong ground shaking in the
l
area is expected to be the San Andreas fault.
An earthquake of Richter magnitude 8.0 to 8.5 is
expected in the near future.
Shaking from earthquakes expected on the Nacimiento,
Rinconada and Jolon faults would not significantly
modify the severity of shaking expected from the
San Andreas fault.
The area is located in Zone 2 of the County Seismic
Safety Element. The characteristics of expected
shaking for microzones, based on variations in
rock/soil type, are summarized in Tables 14 and
15 and Figures 41 through 43 of this Element, and
in Tables 1 and 2 of the Paso Robles Element.
The zones are delineated on Plate IA of the County
Element and Plate I of the Paso Robles Element.
Secondary Hazards
Areas susceptible to damaging settlement, parti-
cularly as a result of earthquake shaking, are
limited primarily to those underlain by relatively
thick sections of loose, Recent alluvium such as
that found in the present channel of the Salinas
River where the risks from flooding exceed those
from settlement or liquefaction.
Hazards from liquefaction are greatest in the active
river channels, but, as noted above, the flood
hazard in these areas probably exceeds that from
liquefaction. A low to moderate.hazard is present
in those areas located on terrace deposits or
Paso Robles Formation (Id" zones on maps from
both elements noted above) where groundwater is
shallower than 30 feet. The liquefaction potential
is considered very low to non-existent on the
firmer and better consolidated rock.
2•S9
The landslide risk rating is low.to negligible
in most areas near Paso Robles, but increases to
moderately high in the bedded Tertiary rock at
Atascadero and along the west edge of Paso Robles.
These areas are delineated on Plate IB of the
County Element and Plate I of the Paso Robles
Element.
Tsunamis and Seiches
Tsunamis, or "tidal waves", are limited to the coast-
line of the County, and are not a hazard in this
area.
True seismic seiches are not considered as con-
stituting a significant hazard in this area.
S. Pismo Beach, Arroyo Grande, Grover City Oceano and
Vicinity
Conclusions regarding seismic and geologic hazards are
summarized from the Seismic Safety Elements of -the Cities
of Pismo Beach, Arroyo Grande, and Grover City and from
the County Element for other areas.
Active Faulting
No active or potentially active faults, as defined
by the State Geologist and the State Mining and
Geology Board, are known to he present in, or in
the near vicinity of the area.
Ground Shaking
The primary source of strong ground shaking in the
area is expected to be the San Andreas fault. An
earthquake of Richter magnitude 8,0 to 8.5 is expected
in the near future.
Shaking from earthquakes expected on the Rinconada
and Offshore faults would not significantly modify
the severity of shaking expected from the San
Andreas fault.
The area is located in Zone 1 of the County Seismic
Safety Element. The characteristics of expected
shaking for microzones, based on variations in
rock/soil type, are summarized in Tables 14 and
15 and in Figures 38 through 40 of the County
Element, and in tables and figures in the
City Elements. The zones are delineated on Plate 2A
of the County Element and on Plate I of the Elements
for the Cities noted above.
Secondary Hazards
Liquefaction potential is moderate to high in Recent
alluvium (Ile" zones), including beach sand, and
in landslide deposits where the water table is
less than 30 feet from the surface. A low to moderate
potential is present under similar groundwater con-
ditions at sites underlain by older sand dunes,
terrace deposits and "Paso Robles Formation" ("d"
zones). These zones are delineated on Plate 2A of
the County Element and in greater detail on Plate I
of the City Elements.
Settlement has a comparable level of potential hazard,
but does not require a shallow groundwater condition.
Landslide risk is rated high on known landslides and
Tertiary sedimentary rocks in steeper terrains;
moderately high on Tertiary sedimentary rocks in low
to moderate terrain; low to moderate on the terrace
deposits and the "Paso Robles Formation"; and negligible
on alluvium and older sand dunes. These risk cate-
gories are delineated on Plate 2B of the County Element
and in greater detail on Plate i of the Elements for
Arroyo Grande and Pismo Beach.
Tsunamis and Seiches
Tsunamis, or "tidal waves", are potentially dangerous
2.60
along the beach areas if the tsunami and high
tide should occur in phase.
Considerations and res onse recommended by the
State Division of Mines and Geology are included
in the Morro Bay Seismic Safety Element.
True seismic seiches are not considered a hazard
in this area.
6. Cambria and Vicinity
Conclusions regarding seismic and geologic hazards are
summarized on the basis of data included in the County
Seismic Safety Element.
Active Faulting
No active or potentially active faults, as defined
by the State Geologist and the State Mining and
Geology Board, are known to be present in, or in
the near vicinity of, the area.
Ground Shakin
The primary source of strong ground shaking in the
area is expected to be the San Andreas fault. An
earthquake of Richter magnitude 8.0 to 8.5 is
expected in the near future.
Shaking from earthquakes expected on the Nacimiento
and Offshore faults would not significantly modify
the severity of shaking expected from the San Andreas
fault.
The community is located in Zone 1 of the County Seismic
Safety Element. The characteristics of expected
shaking for microzones, based on variations in
rock/soil type, are summarized in Tables 14 and 15
and Figures 38 through 40 of the County Element.
The zones are delineated on Plate 2A of the County
Element.
Secondary Hazards
Shaking from earthquakes expected on the Rinconada
The settlement and liquefaction potential is moderate
and Offshore faults would not significantly modify
to high on Recent alluvium along creeks in this area
the severity of shaking expected from the San Andreas
("e" Zones), and low to moderate on Quaternary
fault.
terrace deposits ("d" Zones). These zones are
The community is located in Zone 1 of the County Seismic
delineated in Plate 2A of the County Element.
Safety Element. The characteristics of expected
Landslide risk varies from high on Franciscan bed-
shaking for microzones, based on variations in
rock, to moderately high on Cretaceous rocks, to
rock/soil types, are summarized in Tables 14 and 15
low to negligible on the terraces and valley allu-
and Figures 38 through 40 of the County Element. The
!
vium. These zones are delineated in Plate 2B of
zones are delineated on Plate 2A of'the County
the County Element.
Element.
Tsunamis and Seiches
Secondary Hazards
Tsunamis, or "tidal waves", are potentially danger-
The settlement and liquefaction potential is moderate
ous along the beach areas if the tsunami and high
to high on Recent alluvium along creeks in this area
tide should occur in phase.
(VIVVI Zones), low to moderate on Quaternary terrace
deposits (I'd" Zones), and very low to essentially
Considerations and response recommended by the
non-existent on bedrock ("c" Zones). These zones
State Division of Mines and Geology are included
are delineated on Plate 2A of the County Element.
in the Morro Bay Seismic Safety Element.
Landslide risk varies from moderate to moderately
True seismic seiches are not considered a hazard
high on bedrock to low or negligible on alluvium.
in this area.
These categories are delineated on Plate 2B of the
County Element.
7. Nipomo and Vicinity
Tsunamis and Seiches
Conclusions regarding seismic and geologic hazards are
Tsunamis, or "tidal waves", are limited to the coast -
summarized on the basis of data included in the County
line of the County, and are not a hazard in this
Seismic Safety Element.
area.
Active Faulting
True seismic seiches are not considered as constituting
a significant hazard in this area.
No active or potentially active faults, as defined
by the State Geologist and the State Mining and
Geology Board, are known to be present in, or
in the near vicinity of, the area.
Ground Shaki
The Primary source of strong ground shaking in the
area is expected to be the San Andreas fault. An
earthquake of Richter magnitude 8.0 to 8.5 is
expected in the near future.
2.61
C. Effects on Utilities
The effects of strong earthquakes on utility systems have
been a major concern in recent years because of the exten-
sive damage to these "lifelines" of the community during
the 1971 San Fernando earthquake. A recent summary study
by Moran and Duke (1975) of the damage to public utilities
as a result of the San Fernando earthquake concludes:
"l. Modern steel water storage tanks and old water -
reservoir roof structures performed poorly. Old
hydraulic earth -fill dams, not designed to resist
earthquake loads, performed poorly, with two exper-
iencing near -failure.
2. Underground conduits for water, sewage, storm -
water, gas and petroleum were damaged, mainly because
of permanent differential ground -movements rather than
due to vibration. Effective preventive measures in
this field will be difficult to develop. Potential
ground -movement areas should be identified.
3. Large underground structures such as the Finished
Water Reservoir at the Joseph Jensen Filtration Plant
require special attention. Apparently they act
much like structures above grade. More research is
needed, along with development of design criteria.
4. Electrical power equipment performed poorly.
Failures were due to inadequate anchorage and bracing
and in some cases to inadequate aseismic details
within the equipment.
S. Communication equipment in the telephone industry
performed well except for several failures due to
inadequate or poorly detailed and constructed
anchorages and bracing."
Any comparison of the damage at San Fernando and expected
damage in San Luis Obispo County, however, should be
taken in the context that most of the significant
damage in the San Fernando area was along or near the
zone of fault rupture or in areas of very intense growtd
shaking with some liquefaction. Comparable areas in
San Luis Obispo County would be primarily located in
Seismic Zone 4 (Plate IA of County Seismic Safety Element)
near the San Andreas fault.
2. 62
Some damage may occur in the more populous western zones
should liquefaction, differential settlement, or signifi-
cant landsliding occur beneath a structure or along a
buried utility line. Since these effects are normally
a consideration in the design of more important struc-
tures and buried lines and electrical transmission lines
are little affected, future problems in the western '
zones should be limited to older facilities constructed
before soils engineering was an established part of
design and construction.
D. Nuclear Reactor Facilities
Geologic and seismic studies to determine the safety
of nuclear reactor facilities exceed by several orders
of magnitude the depth and detail of similar studies
necessary for the Seismic Safety and Safety Elements
of a General Plan. For purposes of this Element it is
assumed that some finite risk, however small, does exist,
and that it is appropriate to plan for a nuclear accident.
The planning for such an accident, discussed later in
this Element, should in no way be construed to indicate that
the technical analysis of this Element has evaluated the
risk of such an event, or that this report considers the
risk of such and event to be significant.
E. Dam Safety
Geologic and seismic hazards as they affect Jam safety have
been of concern for several decades, but have become
of particular concern since the near -catastrophic failure
of Lower San Fernando ham (Lower Van Norman Reservoir)
during the 1971 San Fernando earthquake. This dam was a
hydraulic fill structure constructed in the early 19ools,
and strengthened in part using modern, Compacted fill methods.
The failure was in the older hydraulic fill portion of the
embankment, and it modern eurthfi9l dam nearby was essentially
undamaged by what must be considered a comparable intensity
of shaking. Also, it should be noted that Pacoima Dam, a
concrete arch structure located north of Sylmar, was sub-
jected to as great or greater intensities of shaking with
relatively little damage. It is for this reason that
concern for seismic effects on the safety of dams has
concentrated on the older hydraulic fill structures in
the State.
Geologic hazards as they affect dam safety are primarily
rupture along an active fault through the dam itself;
and overtopping of impounded water as a result of
massive landsliding into a full or near -full reservoir.
The former is not a significant hazard to any of the
major dams in the County, based on studies of fault
activity for the Seismic Safety Element; and the latter
is of potential significance primarily at Whale Rock
Reservoir. This Reservoir is flanked by serpentine -
bearing Franciscan rocks that are particularly sus-
ceptible to landsliding such as that now active near
the Cayucos-Morro Bay District Cemetary. This, in
conjunction with the proximity of the Reservoir to
developed parts of Cayucos, constitutes the most signi-
ficant dam safety hazard in the County.
Other major dams in the County are of relatively
large size in comparison to potential landslide volumes.
While some landsliding into these reservoirs may occur,
their volumes are probably large enough to accommodate
even a relatively large slide with minimal downstream
risk and only moderate damage to shore facilities
from traveling waves. Whale Rock, however, is relatively
small in comparison to potential slide volumes, and
further study of this potential hazard is recommended.
2.63
V. RADIATION HAZARDS
A. Purpose and Scope of Evaluation
The focus of this section of the Safety Element is on the
possibility of radiation hazards arising from the presence
of nuclear reactors in San Luis Obispo County. Unlike the
analyses of fire, flooding, and geologic hazards, this
evaluation does not in any way attempt to determine risk
criteria or assign levels of acceptable risk. Such
determinations would require prolonged studies which are
clearly beyond the scope of the Safety Element. In con-
trast to a risk analysis, the report assumes that some
level of risk exists, however small, and that there is the
possibility of harmful levels of radiation being released.
In making this assumption, the emphasis of the analysis
shifts from a description of the hazard to a description
of what should be done to respond to it. This is primarily
a concern of emergency preparedness policy, which is
addressed in Section VI and in Volume One, the Policy Report
The purpose of this part of the report is to provide a
brief, general discussion of radiation hazards, and to
define some of the terms used in such discussions. This
is intended to provide a background for the policy recom-
mendations in Volume One regarding radiation hazards.
B. Radiation
Radiation is defined as the release of energy from naturally
occurring elements in the form of particles or waves.
Radiation has always been a part of nature, and we are
subject to certain levels of radiation every day. How-
ever man has achieved the ability to both concentrate
and disperse radiation at levels which do not occur in
nature, and which can be harmful to almost all forms of
life. To understand the hazardous aspects of radiation,
it is necessary to discuss its basic nature.
Z•64
Radioactivity is a state in which certain elements of mat-
ter spontaneously disintegrate and change into different,
more stable elements. In the process of disintegrating,
the elements give off the subatomic particles and wave
energy which comprise the three main kinds of radiation:
alpha, beta, and gamma radiation. Both alpha and beta
radiation are particles of electromagnetic radiation.
Alpha particles are relatively large in'size, and have
only a weak ability to penetrate very far through the air
or any other substance. On the other hand, beta particles
are high speed electrons which have a significantly
greater penetrating power. Most biological damage from
alpha and beta radiation is limited to the skin, unless
taken internally, in which case these types of radiation
can be extremely hazardous.
Gamma rays, which are related to X-rays, are a form of
wave energy. Gamma radiation penetrates organic matter
readily and can do great damage to virtually all of the
body's organs. A lead or some other heavy metal shield
is necessary to screen against gamma radiation.
Different measures of radiation have been developed, and
most are based either on the rate of disintegrations
taking place in an element or on the dosage of radiation
received by an organism. The base measure of disinte-
grations is the curie, which is defined as 3.7 x 1010
disintegrations per second, and is about equal to the
radioactivity of one gram of the element radium and its
decay products. Since 37 billion disintegrations is too
large a number for practical purposes, smaller measures
based on the curie are the millicurie (one -thousandth
of a curie), the microcurie (one -millionth of a curie),
and the picocurie (1� of a curie). 'these measures are
not dosages, however. The roentgen (abbreviated r) is a
dosage measure of the number of ionizations caused by
radiation in air. It is defined as the amount of
0.
radiation causing 1.6 x 1012 ionizations in one cubic
centimeter of air. (An ionization occurs when a neutral
atom loses an electron to become negatively charged.)
Since the concern of dose rates is with living tissues,
rather than air, the rem and rad measures were developed.
The rad is defined as 000 erg—s7a unit of energy) absorbed
by one gram of tissue. The rem (for roentgen equivalent
man) is a very similar measure which takes into account
the relative biological effects of radiation. For the pur-
poses of the following discussion of the effects of radi-
ation, the rad and rem will be considered as the approxi-
mate equivalent of a roentgen.
C. Effects of Radiation
Radiation affects living organisms by injuring or killing
cells. Just as radiation causes ionization of air mole-
cules, it also causes ionization of the molecules which
make up the cells of living tissue. This results in the
deterioration and death of the cells.
It has been determined from accidents which resulted in
radiation exposure that a dose of 100 r is fatal to all
humans. It is estimated that the lethal dose for 50 per-
cent of a given population (termed the LD-50) is about
500 r. Radiation sickness develops at levels of 100 to
300 r, and is symptomized first by nausea, vomiting,
diarrhea, and various nervous disorders. These symptoms
are followed by a period of relative well-being and then
by secondary symptoms, including a decrease in red and
white blood cells, hemorrhaging just under the skin, loss
of hair, and ulcers of the mouth and stomach. These symp-
toms also diminish and a slow recovery begins. The cells
most sensitive to radiation are those which have the
highest reproductive rates under normal conditions. These
include the blood -forming tissues, bone marrow, lymph
nodes, spleen, reproductive organs, and intestinal lining.
2..65
The eye lens is also quite sensitive to radiation and can
develop a cataract or opacity. Between 25 and 100 r no
visible symptoms occur, but the number of white blood
cells decreases. Below 25 r, no measureable changes have
been observed.
Most of us are exposed to about 0.1 r over a year's time
from naturally occurring sources. These sources include
cosmic rays from outer space, radioactive elements within
our own bodies, and radioactive elements in the rocks and
soil around us. At higher altitudes, about 50 percent
more radiation is picked up by people because of greater
exposure to cosmic rays. X-ray examinations are another
common source of radiation exposure. Whether these low
levels of exposure are harmful is open to some question.
While there are no immediate symptoms to low levels of
radiation, there is the possibility that long-term ex-
posure to low levels of radiation may have the same
effect as an equivalent single high dose. That is, it
may make little difference whether a person is exposed
to 1 r per year for years or 10 r in a single year.
There is little evidence at this time to provide any
sure answers to this question.
D. 'Nuclear Power Plants
The potential for radiation hazards due to the presence
of nuclear reactors in the County arises from the use of
highly radioactive elements as the fuel for heat within
the power plant. Reactors, such as those under con-
struction at Diablo Canyon, typically use a mixture of
two isotopes of uranium as fuel. The uranium is packed
as pellets into stainless steel or zirconium alloy rods
and grouped in subassemblies. Water is passed through
these rod assemblies which causes it to boil. The re-
sulting steam is bled off and turns a turbine generating
power.
The possibility of radiation hazards at power plants are
c. Class C. Release of radioactive material will almost
well recognized, and deterrents to potential accidents
certainly require that on -site personnel not actively en -
are incorporated. into the design, construction, and op-
gaged in recovery actions be evacuated to radiation safe
erational procedures of nuclear power plants. Automatic
off -site locations. In addition, off -site releases will
safety devices are built into power plants to counteract
exceed permissible levels of radiation in uncontrolled
the failure of any part of the reactor system. Those
areas. Some off -site emergency actions are required
measures have reduced the probability of an accidental re-
(see IlI Radiation Countermeasures).
lease of radiation to very low levels. However, even
though accidents at plants are most unlikely, it is pru-
At the low end of the range, only minor measures such as
dent to assume that an accident is possible and to plan
controlling access to the affected areas and instructing
for emergency responses.
people in the area to remain indoors will be required.
At the higher end of the range, some off -site personnel
The State of California Nuclear Power Plant Emer enc Re-
may be evacuated.
s ons�e Plan assumes that accidents of different orders of
magnitude may occur in the delivery, use, disposal, and
d. Class D. Release of radioactive material requires im-
storage of radioactive fuel. These accidents are postu-
mediate evacuation of on -site personnel not actively en-
lated to result in the release of radioactive material
gaged in recovery action and evacuation of the populated
into the air or water. The categories of accidents are
zone far enough downwind from the plant sufficient to
summarized below:
clear an area in which permissible levels of radiation
for an uncontrollable area are expected to be exceeded.
1. Atmospheric dispersion
2. Water dispersion
Classes A through D involve release of airborne radio-
active material from a plant. The escalation from one
Accidental release of liquid radioactive material is
class to the next will initiate or increase the involve-
either a Class E or F.
ment of different support groups and the implementation of
additional protective actions.
a. Class E (on -site)
a. Class A. Confined to a single plant structure. Re-
Liquid releases confined and controlled on -site. They do
lease of radioactive materials does not exceed accepted
not pose a threat to persons outside the immediate area
safety limits. Therefore, no measures are required to
unless the liquid release also results in releases of air -
protect persons in areas.outside of the affected structure.
borne radioactive material.
b. Class B. Release of radioactive material from plant b. Class F (off -site).
structures which may require that protective actions be Liquid releases off -site which are in excess of permissible
taken to prevent exposure and contamination of on -site per- amounts could pose a threat to the health and safety of
sonnel who are not required for recovery actions. It is
not expected that a class B release would produce dose
rates, or iodine levels sufficient to initiate protective *Title 17, California Administrative Code, Section 30368
measures off -site. and 30269.
2.66
61
the general population, livestock and wild life. Primar-
ily, the threat would occur only if the outfall discharges
directly into a river or watercourse used as a drinking
water source or for recreational purposes. Discharges of
hazardous quantities of radioactive materials into such a
stream would create an immediate problem. A discharge
into the ocean would not create such an immediate problem.
Long term exposure pathways might include contamination of
fish and shellfish used as a source of food for human con-
sumption. Genetic effects to oceanic life from exposure
to contaminated sediment and immersion in the contaminated
water could also occur.
These potential nuclear accidents form the basis of emer-
gency response planning in the state plan. At this time,
San Luis Obispo County is in the process of preparing
its own Nuclear Power Plan Emergency Response Plan in
accordance with State guidelines.
E. Nuclear Fuel Transport
In addition to planning for potential accidents at the
nuclear power plant itself, it is prudent to plan for an
accident during the transport of the radioactive fuel
for the plant. Safety concerns arising from nuclear fuel
transport center on the transportation of irradiated "spent"
fuel removed from the power plant's reactor. Transpor-
tation of "fresh" fuel from the fabrication plant poses
minimal problems compared to "spent" fuel because it
has not been irradiated, and therefore, does not constitute
a radiation hazard to anyone near the vehicle.
As with the power plant itself, the primary deterrent to
potential accidents during the transportation of spent
fuel is the design and construction of the containment
vessels called casks used in shipping. The two primary
agencies governing transportation of irradiated fuel
are the U.S. Nuclear Regulatory Commission (NRC) and the
U.S. Department of Transportation (DOT). The NRC regulates
2_67
possession of radioactive materials, transportation pro-
cedures, and shipping cask criteria. DOT regulations
cover additional procedural and packaging requirements.
The basic criterion for design of shipping casks is
that there be no loss of containment of radioactive
materials following a specified "design basis accident."
NRC regulations specify that the design accident is
assumed to occur in the following sequence:
(1) a 30-Foot free drop onto a flat unyielding surface
with the cask oriented such that maximum damage
will occur,
(2) a 40-inch free drop onto the top end of a six-inch
diameter, eight -inch high mild steel bar with the
cask oriented such that maximum damage will occur,
(3) exposure to a 14750F fire for a 30-minute period with
no artificial post -fire cooling,
(4) immersion of the entire cask in water to a depth
of three feet for at least eight hours.
These criteria represent an accident which may be des-
cribed as something like the following: a shipping cask
on train passing over a freeway is thrown off the train
when the train is derailed. The cask lands 30 feet
below on the freeway, and is hit by a tank truck carrying
jet aviation fuel which explodes into flames. The cask is
enveloped in flames for 30 minutes. Then it rolls off
the road into a lake and is submerged for eight hours
before being recovered. NRC regulations require that the
cask survive this magniutde of accident with no loss of
containment.
There are presently three methods of transporting loaded
casks: truck, rail, and barge. The use of barges has
practically been eliminated because they are more costly
and less convenient than truck or rail transport. Trucks
are widely used now, but with the advent of larger,
heavier casks there will probably be a decrease in the use of quantities of nuclear fuel which are significant
of trucks because of highway weight restrictions. This from a weapons standpoint require two drivers for each
leaves rail transport as the primary mode for shipping truck escorted by a separate vehicle carrying armed
irradiated fule. guards. In cases where shipments are unescorted, the
truck is equipped with special protective features and
In San Luis Obispo County, there is only one rail line, direct radio communication between the vehicle and a
the Southern Pacific line, and it does not serve the relay station. In the event of a diversion attempt,
Diablo Canyon area directly. The proposed transportation the objective of the security system is to protect the
procedures for removing irradiated fuel, then, involve a crew, secure the cargo, and enable the crew to call for
combination of rail and truck transport. This method reinforcements. It is likely that local law enforcement
involves a special -permit overweight truck movement from agencies would be called on to assist in such an event,
the reactor to the nearest railhead, which is in the or in the event of an accident involving spent fuel.
City of Pismo Beach. The railhead transfer is a drive -on,
drive -off procedure similar to the "piggyback" loading
method now used in transporting other commodities.
At this time, trucks carrying irradiated fuel have not
been given permission to use U.S. Route 101 because of
weight and speed restrictions: The most likely truck
route from the power plant will be along the P G h E
access road to Avila Road, along Avila Road to Palisades
Road, Palisades Road to Shell Beach Road, Shell Beach
Road to Highway land Highway 1 to the railhead. There
is some question as to whether these roads will be able to
carry the weight of loaded trucks, and it may be necessary
to upgrade the existing road surfaces. One alternative
that has been suggested would be for P G & E to construct
a new road designed to carry the trucks. A new road
could be constructed to avoid transporting the irradiated
fuel through Pismo Beach. One suggested route is through
Crag Canyon and through the canyon east of the hills
bordering Pismo Beach. Another alternative would be
the construction of a rail line from the existing Southern
Pacific line to the community of Avila near the P G $ E
access road to Diablo Canyon.
Whatever transportation mode is used, NRC regulations
require strict monitoring of the movement of radioactive
material. One area of concern regarding fuel shipments
is the possibility of sabotage of spent fuel casks or
theft of fresh fuel for use in atomic weapons. Shipments
2.08
0.
VI. EMERGENCY PREPAREDNESS
A. General Statement
One of the central purposes of the Safety Element is to
provide an analysis of the risk posed by several different
types of.hazards. An integral part of risk evaluations is
an analysis of the ability of people to respond to expected
hazards. In large measure, how well a community perceives
a potential hazard and how well it is prepared to react
determines the overall impact of a hazardous event. This
is illustrated by the differing responses to two major
tsunamis which hit Hilo, Hawaii, as a result of earth-
quakes in Chile (1960) and Alaska (1964).. In 1960, Hilo
experienced a tsunami in which 61 people were killed and
283 injured. Some of the contributing factors to this
disaster were the failure by some to heed warning signals,
the inexplicable refusal by others to leave hazardous
areas, and the mistaken belief by others that they were in
safe areas. As a result of the disaster, a carefully pre-
pared emergency response plan was prepared which delineated
clear lines of responsibility and provided for necessary
communication systems. In 1964, when the tsunami alert was
issued, Hilo residents were quickly evacuated, and no
deaths resulted.
There are many factors to consider in evaluating emergency
preparedness, but perhaps the most important are (1) emer-
gency response organization, (2) communication system,
and (3) the medical care system. The following sections
provide a summary of the status of each of these factors
in San Luis Obispo County and in the Cities within the
County.
B. Emergency Response Organization
Natural disasters and man-made emergencies are situations
in which cooperation and efficient functioning of agencies
2.69
at all governmental levels is perhaps most vital. Coor-
dination of a complex organization of local, state, and
federal agencies determines the ability of people to re-
spond to a disaster, which, in turn, helps determine the
toll wrought by the disaster. This section traces the
interagency relationships that define the peacetime
emergency response organization within San Luis Obispo
County.
All local governments within California are required by
the California Emergency Services Act (Chapter 7 of
Division 1 of Title 2 of the Government Code) to prepare
an Emergency Plan in conjunction with the State of Cali-
fornia Emergency Plan. The purpose of the local Emer-
gency Plans is to establish the organization which will
plan and conduct services during peace or wartime emer-
gencies. The objectives of the organization are to:
1. Save lives and protect property.
2. Repair and restore essential systems and services.
3. Provide a basis for direction and control of emer-
gency operations.
4. Provide for the protection, use and distribution
of remaining resources.
5. Provide for the continuity of government.
6. Coordinate operations with the emergency service
organizations of other jurisdictions.
These objectives are to be met through specified channels
of authority and mutual aid, when necessary. The concept
of mutual aid is particularly important when dealing with
emergencies such as wildland fire, flooding, and geologic
hazards. These hazards have potential for occurring over
a large area at one time, thereby exhausting the resources
of the local agencies in the area. Adequate response then
requires that other agencies be brought in to assist the
I
local agencies. San Luis Obispo County is the northern-
most county within State Mutual Aid Region 1, which in-
cludes Santa Barbara, Ventura, Los Angeles and Orange
Counties. The County itself forms the next level of
organization as an Operational Area, and the Cities in the
County form the first level of organization (Figure 1).
Although the mutual aid system extends upward to the fed-
eral and state levels, primary control of the emergency
situation remains in local hands, either with the City or
County. The emergency relationships between the Cities
and County are therefore the most critical links in the
system. Figure 2 shows the interjurisdictional emergency
relations for San Luis Obispo County. The request channels
illustrated are based on the use of local resources before
calling for aid from other jurisdictions. It is not neces-
sary, however, that every single person and piece of equip-
ment be committed to an emergency before mutual aid agree-
ments become active. In some large-scale disasters,
regional resources are utilized even prior to a request
for assistance. For smaller scale emergencies that may
affect only one or two cities, the normal procedure is
for the City to use up its resources and then request aid
from the San Luis Obispo County Sheriff. The Sheriff acts
as the Operational Area coordinator and employs his per-
sonnel and equipment to meet the situation. Should these
not prove sufficient, he requests support from other
Cities in the County and then from the Regional Mutual Aid
Coordinator.
One of the potential problems with mutual aid agreements
is that each jurisdiction, in relying on other jurisdic-
tions for help in a major disaster, may fail to provide
adequately for its own self-sufficiency. Both the Seismic
Safety and Safety Elements are intended to help mitigate
this potential problem by providing some estimate of the
magnitude of emergencies which can be expected in an area.
These estimates indicate that large scale emergencies,
2 •70
Figure 1.
Mutual Aid System
Federal
Declaration of National Disaster
Western States Regional
Federal Office of Emergency Preparedness - Region 9
State
Governor
Office of Emergency Services
Southern California Region
Mutual Aid Region I
(San Luis Obispo, Santa Barbara, Ventura,
Los Angeles, and Orange Counties)
Operational Area
San Luis Obispo County
Local Jurisdictions
Cities of San Luis Obispo, Paso Robles,
Morro Bay, Pismo Beach, Arroyo Grande, Grover City
Mutual Aid
Region
Operational
Area
I
I
Figure 2.
Interiurisdictional Emergency Relationships
State of California
Office of Emergency Services Headquaraters - Sacramento
Mutual Aid Region I
Emergency Operating Center - Los Angeles
San Luis Obispo County
Courthouse Annex
San Luis Obispo
City of San Luis Obispo
City Hail
City of Paso Robles Grover City
City liall City Hall
City of Morro City of Arroyo Grande
City Ilall City Ball
I\ �-City of Pismo Beach
----- City Ilall------
- — — i Indirect relationship; requests for aid come through
Operational Area Coordinator (County Sheriff).
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primarily a major earthquake, can be expected in San Luis
Obispo County and Southern California as a whole, which may
strain mutual aid capabilities to their limit. It is ad-
visable that each jurisdiction in San Luis Obispo County
be prepared to rely on its own resources for at least a
short period of time.
C. Communications
1. Inventories
The communications system which links individual emergency
agencies is of critical importance to successful response
to a disaster. This section traces the individual channels
of emergency communication within San Luis Obispo County
and links between County, state and federal agencies.
a. Federal
The principal emergency warning system at the national
level is the National Attack Warning System (NAWAS), which
was developed primarily to warn people and provide emer-
gency information during wartime emergencies. Portions of
the system are used, however, for peacetime emergencies,
augmented by state and local systems as appropriate. The
system is a dedicated wire -line system which provides two-
way voice communication between Federal Warning Centers
(i.e., Washington D.C., Colorado Springs), states' Warning
Points (Sacramento), and substate Warning Points (Santa
Barbara).
The NAWAS system is also connected to the State's Bell and
Lights warning system. This system is a wire -line system
which activates an instrument to display a series of color -
coded lights corresponding to a signal transmitted from
the substate Warning Point.
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b. State
Emergency communications within California utilize either
the California Communications System or one (or several)
of a variety of other communication networks in the state
which are linked to local government facilities. The
California Communications System includes the following:
(a) Very High Frequency radio voice networks which:
(1) provide line -of -sight coverage;
(2) use mountain -top repeaters for extended cover-
age; and
(3) interte to microwave relays to provide state-
wide coverage.
(b) Telephone circuits:
(1) commercial, public, and private -line; and
(2) microwave (State Integrated System).
(c) Teletype circuits:
(1) wire; and
(2) radio.
Other communications systems which may be used in major
emergencies, but which normally are used for other pur-
poses, include these:
(a) Radio
(1),Intercity Law Network
Serves all OES facilities and interconnects
law enforcement agencies of 51 counties and
87 cities. This system is microwave-intertied,
to provide statewide coverage. The Intercity
Law Net system is the State's radio hackup to
the NAWAS system.
L
(2) Local Government (LG) Radio System
Serves all DES facilities, a number of state
agencies, and county -level civil defense agen-
cies participating in the system. The LG sys-
tem is microwave -interconnected for statewide
coverage.
(3) DES Fire Network
Serves all OES facilities and fire support
equipment. Radio equipment on this network is
located with fire service agencies in 52 count-
ies. The network employs mountain -top mobile
relays and interconnects to the State Microwave
System to provide statewide coverage. Four ve-
hicular mobile relays are available to provide
coverage in any area not covered by permanent
mountain -top relays.
(4) Radio Amateur Civil Emergency Services (RACES)
Serves all DES facilities and most local juris-
dictions. RACES operates on radio amateur fre-
quencies by authority of the Federal Communica-
tions Commission (FCC) in support of emergency
communications. RACES can augment existing
systems, substitute for damaged or inoperable
systems, and establish communications links with
otherwise inaccessible areas.
(5) Other State Agency Radio Systems
State agencies with available systems include:
Agency
Coverage
Fish and Game, Department of
Regional
Forestry, Division of
Statewide
Highways, Division of
Regional
Highway Patrol, Department of
Regional
Justice, Department of
Statewide
Water Resources,.Department of
Regional
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(6) National Communications System II (NACOM II)
A high -frequency single-sideband radio system
which provides radio backup to NACOM I described
under (c)(2) below.
(b) Telephone
(1) Commercial and Dedicated Landline (Wire) System
(a) Common Carrier telephone service is pro-
vided in sufficient quantity to support all
emergency systems.
(b) National Warning System (NAWAS) is described
in Attachment C, Warning System, paragraph
B, "War Emergency Warning System."
(c) Utilities Hotline is a private line from OES
headquarters to two utility companies which
subsequently disseminate information to all
utilities in the state.
(d) Telephone Company Emergency is a "hotline"
to the Pacific Telephone Company emergency
center in San Francisco, for fanout to
telephone companies.
(2) Microwave
Microwave telephones access those state agencies
having a microwave telephone capability. These
include: .
(a) Office of Emergency Services,
(h) Highway Patrol,
(c) Division of Forestry, and
(d) Division of highways.
(c) Teletype
(1) California Law Enforcement Telecommunications
System (CLETS)
Has 900 terminals in California and serves all
58 counties.
(2) National Communications System I (NACOM I)
A Federal Government teletype system using
leased landline facilities of the telephone
companies for transmitting information to the
federal Office of Civil Defense and Office of
Emergency Preparedness and to other states.
Furnished and installed at DES headquarters by
OCD.
(3) DES Regional Teletype System
Terminals are available at DES headquarters and
each OES regional facility. System is used to
coordinate interregional mutual aid operations.
(4) Division of Highways Teletype
A receiver located at OES headquarters re-
ceives road, weather, and river information for
further distribution by OES.
(5) Commercial Dial Teletype
Information can be transmitted to and received
from other subscribers nationwide.
c. Local
The primary emergency communications system in the County
is that of the Sheriff's Department, since the Sheriff acts
as the Operational Area Coordinator. The Sheriff's com-
munications equipment consists of the following:
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(a) One base station KMG 280, 39.18 mc.
(b) Thirty-five mobile units, 39.118 mc.
(c) -Four portable base stations, 39.18 mc.'
(d) Three handi-talkies, 39.18 mc.
(e) Seven handi-talikes, 154.? mc.
(f) One base station KNF 84, 19S.03 mc., operating in
the state-wide all points system.
(g) Teletype hookup with all police agencies in the
county, and state-wide teletype cababilities through
CLETS.
In addition to the Sheriff's radio, the following communi-
cations systems are available for utilization in an emer-
gency:
(a) County fire radio - (base station and mobiles);
(b) Local government radio (base station and mobiles -
e.g., County Engineer);
(c) RACES radio (base station and mobiles with multiple
modes of operation, including radio teletypewriter);
(d) Department of Justice (CLETS) teletypewriter;
(e) California Highway Patrol radio (monitor only); and
(f) Commercial telephone.
Should these systems not he able to handle communications
needs adequately, radio systems used by industry, general
contracting, trucking, taxi, railroad, and aviation can
be used.
Among the cities in the County, communications inventories
are quite similar and normally consist of the police radio
the fire department radio, local government department
radios (e.g., City Engineer), amateur radios (e.g., RACES,
REACT'), and commercial telephone. The Cities in San Luis
Obispo County have sufficient inventories of communica-
tions equipment, but the kind of equipment may not be
suited to large scale coordination among the cities in the
i( !
n
s
0
event of a major disaster. In most cases, interdepart-
mental communication (or at least monitoring) is possible
in individual cities. Communication between departments
of different cities, however, is not possible. This can
prove to be critical in major emergencies. As an illus-
tration, in the recent Big Tujunga fire in Los Angeles
County, mutual aid agreements were activated which in-
volved numerous cities and several counties. It was not
uncommon for response units from as many as five or six
cities to be working together in the same canyon. In one
canyon, units from the cities of Glendale, South Pasadena,
Pasadena, Alhambra, and Covina had set up a line of de-
fense, but it was not possible for these units to communi-
cate by radio with one another. As a result, it was nec-
essary to communicate by runner, and this severely hampered
the total response effort. It was not unusual for a truck
to have its water supply cut off without prior warning.
2. Actions
As examples of the way in which the communications networks
would work, the following illustrations of major emergen-
cies are provided.
a. Flood
Major floods are usually preceded by a buildup period during
which resources and personnel can be marshalled to respond
to the emergency. During this period, the State Office of
Emergency Services gathers data from the Weather Bureau and
the Water Resources Department and relays this information
to the affected operational areas. The OES receives this
information by teletype service and the Division of Highways
teletype system, and relays it by the OES private teletype
and to local governments by the CLETS system. Local
governments then use their own systems to facilitate evacu-
ation and rescue should that be necessary.
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b. Fire
Initial warnings of a major fire usually come from the af-
fected area itself and are issued through the Area or
Regional Fire Coordinator. These warnings can utilize any
of several communication channels that are available and
appropriate. Requests for mutual aid can also use several
channels of communication and are made through the Area or
Regional Fire Coordinator.
c. Earthquake
Since earthquakes occur without warning (under existing
scientific capability), communications are limited to re-
sponse. Notification of an earthquake, damage reports,
and requests for aid can come from several sources, in-
cluding seismological observatories, OES regional.offices,
local governments, federal and state agencies, and the
Honolulu Observatory. This information may be received
via NAWAS, radio, teletype, telephone, and any other avail-
able means.
d. Tsunami
Tsunamis, or seismic sea waves generated by earthquakes,
usually travel at tremendous rates of speed, often near
400 miles per hour. An earthquake occurring closely off-
shore would leave little opportunity for warning. Tsu-
namis generated farther out in the Pacific Basin, how-
ever, do allow enough time for warning. Reports of major
earthquakes are transmitted to the lonolulu Oh_urvatory
for evaluation. The Observatory transmits the ::ppropriate
information via Federal Aviation Administration circuits
to San Francisco, where it is fed into the NAWAS system,
and then to coastal counties Warning Points. 'Phis same
information is also transmitted to :.ocal jurisdictions by
appropriate radio systems, teletype, and telephone cir-
cuites to ensure maximum dissemination.
n
D. Medical Care
One of the most urgent functions of the emergency prepared-
ness organization is the provision of adequate medical care
to those injured in a major disaster. The ability to care
for a large number of injured persons quickly is a major
factor contributing to the reduction in loss of life caused
by disasters. The County's Emergency Plan recognizes this,
and calls for medical care facilities to be prepared for
a sudden increase in patients of about 50% of their normal
patient population.
The California Emergency Medical Mutual Aid Plan also pro-
vides guidelines to the County regarding major disasters
and medical response. The highest level medical emergency
envisioned by the Plan is termed a Level III emergency and
is described as follows:
Medical resources in or near the impact area are over-
whelmed due to either sheer numbers of casualties and/or
damage to the medical resources. Deficiencies in material
and/or personnel are such as to require extensive medical
mutual aid from outside the county. In this event, the
following can be anticipated to apply:
a. A "State of Emergency" may be proclaimed by the Gover-
nor;
b. Field treatment may be accomplished, in many cases, by
paramedical and/or non -medical personnel;
c. Ambulance services will be inadequate to cope with the
numbers of casualties and other transportation resources
will be required;
d. Regular ambulances may be reserved for transfer of cas-
ualties between medical facilities for specialized treat-
ment rather than for scene -to -facility transportation;
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e. Surviving medical staffs whose normal facilities are
damaged and inoperable should turn their attention to
field treatment (triage, etc.);
f. Peripheral medical' facilities should concentrate on
receiving immediate treatment cases from the impact area,
rather than providing support into the impact area; and
g. The "Leap Frog" concept (see Figure 3 ) may be uti-
lized to transport:
(1) Stabilized casualties to outlying medical facili-
ties;
(2) Special treatment casualties (e.g., burn cases)
to specialized medical facilities which may be some
distance from the impact area; and
(3) Emergency medical personnel, equipment and sup-
plies from outlying facilities to the impact area; and
h. Peripheral County Emergency Medical Coordinators and
the OES Regional Emergency Medical Coordinator will find
it necessary to concentrate on coordinating the additional
tasks of bringing medical personnel from considerable dis-
tance to support field operations and moving casualties
considerable distances to outlying medical facilities.
This magnitude emergency is conceivable in San Luis Obispo
County given a major earthquake or flood. One of the most
important concepts of the plan is the Leap Frog concept.
This concept involves evacuation and transport of (1) sta-
bilized casualties to outlying medical facilities,
(2) specialized treatment casualties (e.g., burn cases)
to special medical facilities which may be some distance
from the impact area, and (3) emergency medical personnel,
equipment and supplies from outlying facilities to the
impact area. The purpose of these actions is to see that
surviving medical facilities will not he overloaded with
1
r)
casualties or given cases they are not equipped to treat.
Lesser levels of medical emergencies are possible, of
URBAN AREA
course, and the emergency medical facilities in San Luis
HEAVILY
Obispo County should be able to respond adequately to
DAMAGED
localized multiple casualty emergencies. The emergency
facilities in the County are shown in Table 12 (including
Santa Maria Hospital for south County casualties). One
of the critical factors determining the success of the
medical response to an emergency is the ability to effi-
ciently evacuate the injured persons. Evacuation is also
important to preventing injury, as the 1964 tsunami in
URBAN AREA
Hilo, Hawaii, demonstrated.
CLOSE
MODERATELY
Emergency evacuation of the injured is accomplished either
DAMAGED
by ambulance or airlift. All of the hospitals in the
County are served by ambulances, and air rescue services
are provided to the northern part of the County by the
MAST (Military Assistance to Traffic Safety) organization
stationed at Fort Ord, and to the southern part of the
County by the Air Search and Rescue Team at Vandenberg
URBAN AREA
Air Force Base. Evacuation of non -injured persons is not
addressed in the County Emergency Plan or in any of. the
CLOSE
City's Emergency Plans. This type of evacuation is -de -
UNDAMAGED
pendent on several factors, primarily (1) the type of haz-
ard, (2) the severity and location of a hazardous occur -
EXPLANATION
rence, and (3) the mode of evacuation. Generalized evacu-
ation routes within the urban'areas are shown on the •
Natural Hazards Map for each jurisdiction. It should be
272* GENERAL CASUALTIES
URBAN AREA
remembered that these routes are only general recommenda-
tions. Decisions regarding evacuation are hest made when
CASUALTIES REMOTE
MEDICAL MUTUAL AID
more is known about the nature of the hazardous occurrence.
UNDAMAGED
For example, evacuation of a canyon from fire hazard
should proceed on the canyon bottom, directly away from
the fire. Evacuation of the canyon from flooding or dam
inundation should proceed perpendicular to the oncoming
LEAP FROG CONCEPT
water up the sides of the canyon. The Natural hazards map
also shows the relationship between evacuation routes and
Figure 3.
temporary shelters (e.g., schools, fallout shelters).
2. 77
Table 12.
SAN LUIS OBISPO COUNTY
EMERGENCY MEDICAL FACILITIES
24 Hr.
Emergency
FACILITY
ADDRESS
OWNED
BEDS
Service
San Luis Obispo
2180 Johnson Ave.
Governmental
133
Yes
County Hospital
San Luis Obispo
French Hospital
1911 Johnson Ave.
Private
100
Yes
San Luis Obispo
Sierra Vista
1010 Murray
Private
172
Yes
Hospital
San Luis Obispo
Atascadero
5575 Capistrano Ave.
Governmental
27
Yes
General Hospital
Atascadero
Paso Robles
ISth B Terrace Hill
Governmental
32
On Call
District Hospital
Paso Robles
Arroyo Grande
345 Halcyon Road
Private
48
Yes
Community Hospital
Arroyo Grande
Huntington
Highway /1 8
Private
10
Yes
Medical Clinic
South Bay Blvd.
Morro Bay
Santa Maria
Park View Ave.
Private
Unk
Yes
Hospital
Santa Maria
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REFERENCES