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Table V -l., SCENIC HlatIWAY ELEMENT
FINDIMI S
'POLICY
IMPLEMEO VATION
7. Protection of scenic corridors is
largely dependent- on local land
7. Conoider compatible land use
in
7. Amend Zoning Ordinance to implement
'
use regulations.
patterns scenic corridors.
p
County policy.
8. An effective scenic highways program.
S. Promote the county scenic highway
S. Indicate routes on public maps and
requiresactive local support,
including the support of affected
program.
plans. Place "poppy' signs on
property owners.
adopted routes. Encourage advertising
by Chambers of Commerce and others.
Seek citizen participation in all
aspects of the program,
9. Designation of a scenl.c highway can
affect the use and value of adjacent
9. In considering any road designation
9. Consider economic impacts on property
�
property.
as a scenic highway, a public hearing
affected by a scenic highway
shall be held and all adjacent
deRi.gnation.
property owners shall be notified
of the public hearing by mail., in
addition to general notices published
in a newspaper of general circulation.
N 00tiQn V
SCENIC ITIG151AY EMEMIN'I'
A. ORNEIAi,
1. �°tate I3c�c�,.�,rc�menta
Section 65302(h) of 'the Govarnment Code requires county general plans to
include a Scenic Highways Blement for the development, establishment,
and protection.of scenic highways pursuant to the provisions of,.Ahe Streets
and Highways Code."
The General Plan guidelines adopted by the Council on Intergovernmental
Relations in 1373 state that the Scenic Highways Moment should include an
identification and evaluation of scenic corridors, a map of designated routes,
a statement or policies, and a guide to implementation.
2 Planning Relationships
The designation of scenic highways can have a significant impact on physical
development and should, therefore, be coordinated with other development
controls. Special attention should be given ,to existing scenic highway
designations by the State, by adjacent counties, and bNt the incorporated cities
in. Butte County. The routes selected in the Scenic Highway Element should
not conflict with the objectives of other elements of the .Butte County General
Plan. ' Designation of sc-enic ;h.l„ .,Grays should reflect the County's policies
expressed in the Land Use, Open Space, Conservation, and Circulation elements.
V-1
Scenic highway - For the purpos(-) of than olement, A :l(,,attl,a 1,11ghway
Is doflned, as a main gobl.io road t11rc)77gh un arca af �SJgturns
aun
natural landscapoo. The Scenic ll;lghway includes not, only the
Pavement, or traveled roadway but al oo the entire pnbl ial.y-owned
right-of-way. Customary accessory uses usually foutici in ther.ir4b
of -way include bridges, drainage facilities, public util;iti.on,
walkways and trails, protective planting and lands . pirip rest
areas, and vista points.
Scenic Corridor -- The Scenic Corridor can be doscri:bed as 11the
view from the road," The view may be a distant panorama as well
as the immediate roadside arca. Corridor width will vary depending
on terrain, vegetation, and development, A corridor should encom-
pass the outstanding natural :features and picturesque landscapes
Which qualify the highway as nscen c."
Eligible State Scenic Highways - Eligible State Scenic Highways
are those state highways shown on the Master Plan of State $conic
Highways. In Butte County- only Highway 70 north of Highway 149
is eligible for state designation as an Official. State Scenic
Highway,
Official State Scenic Highways Official State Scenic Highways
are those eligible routes whose scenic corridors are protected
by a county-dovel,oped plan which has been found satisfactory and
is adopted by the State Scenic Highway .,Advisory Cotmitteo.
} Offloial C€linty S0011:10 I14,111ways - O Ic;.Ial County` O(.rollic Highways
Include all. coijnty highways designated in 11 `aconlc Iii ghways
Illomont of tho General I'la.n, and whose oorrldor protection plana
are approved by the State
B. OIVECTIVPiS
Butte County has an outstanding va-riety of natural vistas and landscapes
in adopting a Scenic Highways Element the County seeks to proriorve the more
visible portions of this natural scenery.
The primary objective of this elomen-t is the protection and enh,..t cement of
scenic areas adjacent to and visible from selected highways This effort
is consistent wit1-ecommendations of the adopted Butte County General Flan
Open Space and: C �,ervation elements and reflects the Countyls general
goal of maintaining a high quality of life for its residents.
Secondary objectives are to:
Guide future scenic preservation activities;
Direct the development of specific legislation and programs by
the County of Butte;
Coordinate the State Scenic Highways Program with local policies;
and
Heighten awareness of the visual environment and, promote community
pride in, our natural resources.
,
V-
C . 00JUMOR, EVALUATION ANIS aELEf '.C`;lN
For the purp000 of ovalua'Ung the highways An Butte Oou ty, "Inain public
roadall 1,ncl.uda all state h•igrhwaya and county rural, artorrlal.s, a,ollectors,
and. through roads The only long u.npavoe sections evaluated were mountain
roads designated as artori.al.s or collectors by the County Dopartmant of
Public Works. Evaluation was done by Planning Department staff after cin --site
viewing from the road and from turnouts; and, vista points, Ilost reads were
divided into soo ors for evaluation. purposes because of distinct changes
In natural and man-made features Each road and road sector was evaluated
by using the following general criteria.
System Charaoteri;stics (Relation to ,Sooenie TIighway System)
Closeness and convenience to urban population canters.
Entry at County boundaries and urban centers.
Integration. into total system; connection and intersection with
other highways
oA
Access to major recreation meas
Right -of -Way Characteristics
Road surface and alignment; safety.
Lack of tra:ffi.c, stops, and access points; safe'L•y.
Wide shoulders, turnouts, rest; areas and vista points, and
space for such,
,Natural. Corridor Characteristics
Variation in slopes, elevation, and terrain.
Visible rock strata and prominent land farms.
Clarity, depth, and width of vistas, especially horizon
silhouettes and known landmarks.
Abundance and, variety of plant forms, especially .forests,
Abundance and var, lety of native anitnals., onpoci ally docar
and ripar lan, birds
Vicibility and avoaos9.l4li,ty of orooks, rivers.
Man -Made Corridor Charactoristi:os
Low population densities; popul,ati on clusters.
Lack of structures, ospeo idly signs, business and utility
structures.
Land -oriented uses, including agriculture, livestock grazing,
limbar management, and recreation.
Used by vacationers and leisure travelers, access to campgrounds,
parks, trails, or boat ramps.
Historic landmarks, structur-s, and routes.
Government Policies
Land Management by government agencies, especially the U. ,S.
Forest Service and Bureau of Land Managememl',, arid State Departments
of Water Resources and Parks and Recreation.
Eligible State Scenic highway; County HScenic highway" zoning, or.
designation by cities or adjacent counties.
Consistent with. other Butte County General Plan eleMents, ospecially
Land Use, Open Space, Conservation, and, Circulation.
The evaluation also took into account the possible effectsof designation
on property rights, land use, traffic, and the local econorly.
Roads which meet some of the criteria above are shown in Map V-1.
D'. %Oi RIDOR DEVELOPMCNT AND PROTECTION
1, Official State Designation
Although state law requires the County to adapt a Scenic Highways Elemeni,
of the General Plan, it does not'require the scan c highways to be designated
V-5
by the tate an "cafflo-fall, State or 001111ty Scenic hIghfWays. "WrIc°ial
designation qualifies the Gounty for rartain bonofita. `Chose ill ludo th a
placement (if colorful, "poppy signs, �,ndtc��tion cti' xau'tes e�r�,�'i•rata maps,
assistance An underi rounding or utility bines, and tho deavol c pment or rest
arcaas . In general. terms, State designab i on and the ansuing benefits will
roqu.ire the County to request designation, survey each scenic corridor, and
adopt a corridor protection program which As approved by the State, The
detailed procedures for official State designation of scenic bighwtays are
contained, in Append9 x Dl ,
2. Boundary pet ineation
The Scenic Highway Report required for ,State desig zar„ion suggests boundaries
for the scenic corridors along each proposed scenic highway and describes
the scenic elements within the suggested corridor. State guidelines define
the scenic corridor as 'the area of land general:l.,r ,djacent tr, and visible
from the highway which requires protective measures to insure perpetuation
of its scenic qualities.
The Scenic Highway report z quires a discription of the ,scenic elements
which qualified the highway for designation. The corridor should include
outstanding natural elements such as water bodies, mature 'timber stands,
wildlife habitats, and unique landforms as well as man --.nude dams, bridges,
recreation facilities, .his4ori.c sites, and architectural. features. All
types of Landscapes, whether wild,, cultivated) or urban, may have scenic
value and Can be considered for inclusion In a Scenes corridor. Corridor
featurea may be evaluated in terms of 'their distance from the road, size,
farm, and cclor.
V -C
The corridor should, gine ludo nearby land whoro human use or dovel(pont may,
advcroly of oot tho sconox,,y. Tbo advoroo oCfocts to bo oonold'oro(] al'o
primarily visual., but traffic, noiso, and odor- are also :relevant :Impacts,.
MA.f.)r fac;Ptors in rorr'i,dor delineation are :legal and administrative.
Exist. ng public ;Land ownership and the likelihood of some (lovarnment
4r
acquisition should be considered. The boundaries should coi-,ioi.de where -
ever feasible with property lines, zoning district boundaries, city limits,
or other legal. d:s,iaroations. Administrative purpose may in some caseseven
require boundaries; oV a constant distance from the centerline of the highway.
Because of its significance and complexit+r, the delineation process should
be undertaken carefully and with full involvement of all concerned parties.
According to the guidelines for State designation, corridor boundaries should
be determined with the participation of all interested citizens.
3. Development- Controls
a i Right -of --Way
In developing scenic highway's, Section 261 of the Streets and Highway Code
requires the State Department of Transportation to consider pleasing visual
appearance and impact as well as safety, uti
driving on a sooij-ic highway wan be onhanceid If thorn are Power jxocosa points
from roads and driveways. A rurthor (-ons1doT,at,.1o11 in t37o ,neled to Oontrol
the location and design of utility lines and strl,10turo e. Ritybt.«f_way
develo,pmont Min bo enhanoocl by providing areas to turn out, rest,) view -the
scanery, arid, allow traffic to gasp.
b. Adjacent Lands
The maintenance of a pleasing visual landscape along adopted scenic highways
is largely dependent upon local controls over the development and use of
private and public lands within scenic corridora4 Consequently, the local:
Jurisdiction's program for the protection and development of scenic corridors
is the heart of the State's requirements for official designation and
essential to the success of 'a system of sc-cni.c highways. According to State
guidelines, the local corridor protection program Includes regulation Of'
land use,, including outdoor advertising.
The ocrridors along the Qounty's scenic highways now fall within several
different zoning districts. Several of the most, attractive routes were
rezoned in the late 1960ts to a S-H (Scenic.-Highway) classification which
extends 350 feat from the centerline of selected highway sectors, As well
as one residential dwelling per parcel and agricultural uses; the zone
allows by use permit "highway services primarily for the convenience of the
traveling public." The scattering of business usea along the roadside is
generally in conflict with the objectives of the scenic highway program.
Scenic qualities and the safety and convenience of travelers are enhanced
by off-road shopping; centers;, as in Forest Ranch, or compact business
districts, as in Stirling City.
V-8
1
• !-Iost of the valley routes and. some in tho mountains am zoned Agrl eultural:,
'1'f.mbar-Moain,tabi, and 'I';tmbor,l.and T'roserve, which are lntonded to
land- orion•t;ed rural uses. Norio allow commoroial. uses that are not al000'l,y
rel.ra•tod to nratural rosr+aaro as iaaad resource dovol opmont ac;tivi,tI oa,
Rearly all zoning districts allow residential. uses. The protection of
scenic, oorrLdors may require the restriction of residential, locations and
`I
densities.
The effects of development on scenic vistas can often be m;iti g atod by
locating structures farther away f:^ern the roadside., The County now requires
that all permanent structures be located at least 50 or 55 Peet from the
centorlite of tho road. The standard is the same for forads in rural and
urban areas of the County.
Utility distribution lines can usually be placed out of ai.ght. Lines and.
Mowers for power transmission, can bio, placed. as inconspicuously as passible
and designed attractivel..y.
Scenic qualities are affected by billboards or other large off -premise sign.'.
The intrusion of signs into the natural landscape can be 0 ntrollod �
restrictions on their location, size, .ieight, lighting, maintenance, and
purpose-. Current County ordinances only control the street ;setback for signs
and, prohibit off -premise advertising in non-commerioal areas.
Scenic values are affected by changes in the natural landscape, including
burning of vegetation, site clearance, tree removal, grading, cutting, and
filling. 'Those activities can be covered by zoning regulations cx special
ordinances.
V-9
vrotectlon of aenn:tca corr,;dors ra u'I,rns dotrri.,l..od study and plranri rqt, A
opealNe, plan Wit Jllolmudo all land In the corridor and W11 doonribo tho
Gourd,,yls l3ro rtua of pt-bection and r ,,an�,ement The plan, will doal, with
land usn, -the location and deslign of structures, the development of -the
ri.gbt-of-•way, and the prov,14jion oJ," appropriate public, services and, faoilities,.
4.. Local Promotion
A scenic Kighways program will benefit from active local promotion in add-1—
tion
ddltion to official designation.. Tosecure the possible economic b6nefits of
scenic Highway designation, the system needs to be advertised, to potential
visitors.
B POLICIES
w Table V-1 summarizes the f: ndi.ngm diecussed abate, states the Countyf a
policy in response to t> s findings, and olztlines implementation measures.
V-10
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Table 11-2. SEISMIC SAIETY,ELEMDNT
1NDI NC S
POLICY
IMP LEMEWAT ION
1.
Butte County is in an araa of known
faults
1.
Inform the public of current
1.
Approve and publish this plan
and recent seism.'.c activity,
estimates of seismic hazard in
element, Keep the information
all parts of the County.
up-to-date.
2.
The only Known active faultin
Butte County is the Cleveland
2;
Take into account all known.
seismic information in matting
2.
Consider the most recent infor-
mation 'hazard
Hill :fault near Oroville. A. number
hand use decisions, Avoid
on seismic in all
zoning and subdivision decisions.
of faults in or near the County
locating schools; hospitals
shcul.d be considered potentially
and similar uses over known
active, The Proximity of the San
fault areas:
Andreas fault system is generally
si grdficant in evaluating seismic
risk in the County.
3.
The area around the Cleveland Hill
3i
Review th,.
.olicie$ and criteria
3.
Exercise approval authority_�ait�lz
fault has been designated as a
Special Studies Zone under the
establisheL. by the State Mining
respect to all real estate develop -
Alquist-Pri:olo Act, effective Jan-
and Geology Board within the
special stidues zone and consider
ment and .structures for human
occupancy within the Special. Studi.os
uary 1, 1977. (Chapter 7.5,
Division 2, California Code.
implementation.
Zone, as provided by State law.
44,
Portions of the Sacramento Valley
4.
Consider liquefaction potential
4.
Require appropriate design of
have a generally high potential
for
in making land use decisions:
structures susceptible to the
liquefaction during a major >
effects of liquefaction,
earthquake..
1.
The identification of geologic
1.
Inform the public o geologic
1.
Approve and publish the hazard
hazards is in the public interest
hazards.
maps in this plan element recog-
nizing that this map is general
and that each ptoject must be
judged and. each site must be judged
on its individual merit,
2.
Geologic hazards limit land
Consider geologic hazards in
2.
Continue to implement guidelines
development capabilities.
development of Land Use, Housing.,
restricting uses in high hazard
Circulation, Conservation and
areas, established limits on the
Open Space Elements,
density and type of development
permitted in high hazard areas!
3.
The risk of landslides is
3.
Consider lanrlslide potential in
3
Consider -requiring investigation of
greatest in areas with slopes
review of private development and
landslide potential for proposed
over 15%, weak rock and high
puandc5�on�Map�111-1.areasliaclites in rated
developm,ent and presenting findings in
rainfall.
4
environmental review and subdivision
review.
4.
The removal of surface material
4.
Consider erosion potential in
4.
Consider requiring investigation of
by rain and water varies by slope,
review of private development and
erosion potential for proposed
soil, vegetation, precipitation
public facilitie8 in areasrated
development and presenting findin.g5 in
and development. It is greatest
high and very high on Map 111-2.
environmental review and subdivision
in areas of granitic rock,
-review.
.51
Ground surfaces can sink and
5.
Protect against subsidence from
54
Monitor sinking is necessary, i c=_
cause significant damage in
ground water withdr,awl and oil and
tial in rev'Jew
sidev subsidence potent.
areas where there is extensive
gas withdrawL Oppose state plan
of.proposed withdrawl. Support cnnal
ithdrawl of g
wround water, oil
Zo pump our ground water out with
u
project to bring surface waters into
and gas.
deep wells.
Butte County wherever possible,,
Table 111-1. GtOLOGIC HAZARD STJB-=M NT
a
FINDINGS
POLICY
IMPLEMENTATION
6. Many galley areas with clay 6.
soils have a high potential
Protect development in valley
6. Monitor shrinking and swelling as
for structural damage from
areas with expansive soils. -
necessary. Require mitigation
soil ,shrinking and swelling,
measures for large developments
and major facilities when there is
is a high potential for damage,
7. High mater at deep periods 7.
'a
Protect .the river banks with
7. Suppor ded
velapmen ancot�fCo1o
causesignificant erosion
and other problems for Butte
appropriate riprap and. other
devices in support of policies
.
'rater resources, a=
County valley farming areas,
for controlled water develop-
ment in Butte County and out
of Butte County. Support dam
projects in the northern
California area, specifically_
the Cottonwood Creek Dam.
i
rx
Table TV-6. N018E =Mi NT
FINDINGS
POLICY IMPLEKENTATION
I.
Objectionable noise from trans- .
1.
Endeavor to maintai--, an accept-
1,
Consider adoptiong the State's
portation facilities and stationary
able noise environment in all
Model Community Noise Ordinance"
sources can have a significant
areas of the county.
or a modification thereof.
impact on public health and welfare,
2.
Some aspects of transportation
2.
Where nconomically and
2.
Study State and Federal regulations
related noise
e can be controlled by
otherwise feasible
.Correducingtransportation noiso.
the County,
control the sources'df trans-
Consider noise in the location acid
portation noise to maintain
design of County roads. Locate air -
acceptable levels.
craft flight paths away from devc'Ioiled
areas where feasible.
3.
Railroads and highways can cause
5.
Discourage future railroads
3.
Consider noise sources in review of
a sigr.-IIficatn noise problem near
developments.
and highways and other noise
zoning and subdivision proposals,
sensitive activities near
residential developments
consider noise sources in view
of zoning and subdivision pro-
posals and mitigating measures.
4.
Development near aircraft flight
4.
Plan for airport;development pment
4.
Locate noise -sensitive uses away
paths subjects people to objec-
and discourage noise -sensitive
i
from airports. Preparespecific
tionable noise and threatens
activities neat airports,
artEnvironsplans for Chico and
future airport operations.
,
Oroville airports. Encourage. compat-
ible uses in and around airports,
5.
Some types of recreational
5,
Control recreation activities
5i
Place limits of levels or ampliflfcd�
activities make objectionable
that have the potential to cau'se
sound and the time and location of
noise.
objectionalbe noise.
outdoor concerts, auto andmotorcycle
races, and similar noise activilties.,
Identify locations for such activitie8
that are compatible with the public
MISS
health, welfare and safety.
r
t
Table IV --6 NOISE ELEMENT
VINDINCS
POLICY
IMPLEMENTATION
6. State legislation requires
6. Provide 60 dB noise contours
6. Develop 60 dB noise contours
noise insulation of new
around all major sources
around major sources where this
multifamily dwellings con-
information is not presently
structed within the 60 dB noise
available,
exposure contours:
7. Notse problems cross City
7. Cooperate with the incorporated
7. Exchange noise contour iniorma-
boundaries:
cities to resolve mutual noise
:ion. Attempt to develop compatiL-le
problems.
noise control. programs.
8. As the County grows and
8. Keep the Noise Element current
8. Monitor changes in nol.se levels.
activities change, the noise
with changing conditions.
Update noise contour data.
environment will also change.
SONIC HIOVAY ELEMENT
14
FINDINGS
POLICY
IMPLEMENTATION
1.
Butte County has many areas of
1.
protect valuable scenic areas
1.
Develop a system of scenic highway,
picturesque natural landscapes.
for enjoyment by residents and
as provided in the policy statement:,
visitors, however, no particular
area shall be so designated until
a public 'hearing is held thereon,
(Prior to said public, hearing,
notification to all effective
property owners shall be made.)
2.
Officialof
adbc�nei_its
2
2.
Follow procedures in Appendix E.
highways the
t�irspadesz�n�-
tion of eni.chhighways,
local scenic highways program '
particular highway is adopted as
and requires various County
a scenic highway, the specific
actions.
procedures will. be as set out in
Appendix E.
3.
Secaic corridor boundaries
3.
Delineate, scenic corridors with
3.
Survey scenic corridors, Solicit
may include areas visible from
careful consideration of all
citizen parti.cipation,. Prepare
highways, outstanding natural
factors,
"Scenic Highway Report" for each
or.man-made features, land
development6,ma
corridor. Determination of scenic
where affect views.
corridor shall, only be made after a.
noticed piublic hearing.
4,
Development of scenic highway
4.
Consider quality of the view and
5
RequirePlanning Commission annual
rights-of-way may have signifi- ,,
driving safety and design of the
review of major road projects to
cant impact on ,the view and
roadway and other features in the
include concern for scenic values,
driving safety,
right-of-way where economically
feasible;
Table V-2. SCENIC HIGHWAY ELEMENT
FINDINGS
POLICY
IMPLEMENTATION
5,
Numerous vehicle accesso;,nts
5.
Control access to scenic
5•
Utilize existing access where
along scenic highways can effect
highways to maintain safety
feasible. Review encroachment
driver safety and comfort, and
and view, considering all aspects
permits for safety,
roadside. beauty,
of economics and engineering.
6 • '
tYie unsightly view of utility lines
6.
Locate and design future
6.
Review the location and design of
and certain structures
nosy be mitigated by incon-
utility structures to improve
`where
future major transmission lines,
the view, economically
Require the lease con,5p cuous
spicuous siting and pleasing;
feasible.
location of distribtition lines, as
design.
feasible and where there is reasonable
choice.
7..
Protection of scenic corridors
7..
Consider the density and
7.
Amend Scenic -Highway Ordinance to
is largely dependent on local
location: of man-made structures,
implement local County policy.
land use regulations.
inscenic corridors.
$!
Official of
8
plans for each
$,
Savey corridors. Prepare and ado��i
scnichghwaysdrequireson
detailed
scePrenicecorridoxc
land use regulations. Plan develop -
study and planning of scenic
ment of right-of-way and other public
corridors •
facilities.
9.
An eccscenic highways
9.
Invite citizen participation in
9,
Indicate routes on public maps and
program requires activity
local involvement
the scenic highways program.
plans. Place "poppy" signs on adopted
and support
Give notice of all hearings toroutes
;ncourage advertising by
and must have the active support
all affected property 'owners.
Chambers of Commerce and others. Seek
a -ad participation of the property
citizen participation in all aspects
oNmers affected•
of program:
10.
All zonings have an economic 10.
All zoning shallrequire a review
10•
Consider economic effect when ado;,ti.ng
effect,
of economic effect,
Scenic Highway Ordinance,
One
general comunent-;:
The map will only reflect
those highways that have already
been
designated by the county .-o,"scenic
highways,,
FINDINGS
POLICY
IMPLEMENTATION
1.
Fire hazard is a problem for all
1.
Make protection from fire
1.
Consider fire hazards in all land
areas, but I is more pronounced
hazards a consideration in all
use and zoning decisions, environ--
in certain foothill. and mountain
planning, regulatory, and
mental review, subdivision review
areas,
capitol improvement programs,
and the provision of public serviccr,
with spacial concern for areas
where fire hazard is more pro-
nounced.
2.
As population grows, the potential
2,
County should attempt to
2
Require subM.visions and major new develop --
and incidence of fire also grows,
improve fire protection as
ments to make contributions to fire
population grows.
protection services on which they
rely.
3.
.
3.
Use i:uelbrakes along the edge
S ' g
3,
Require fuelbreakcs where feasible
�l
fag�ort�onf�ra�seread�ic;a1
p
of developing areas and in
;� .r ,�
u thin high and extreme fire
"high" and "extreme" fire
hazard areas.
hazard areas;
4
Fire �
Fire rotacti,on facilities and
4.�
Attempt to u r
P upgrade fire.
4.
Promote formation of voluntary fine
.p
g•
se�.vices are mar anal. in some
areas of the Count y�
service where economically
y
feasible.
companies in ct
p remote wand services as
additional facilties ands. Cites as
desired by area residents and as
economically feasible.
5:.
Development in watershed areas
5.
Carefully evaluate development
5
Prepare zoning plans, for critical
can affect community wager
in watershed areas to determine
watershed, areas. Consider possible
supplies,
their effect on community water
effect to watershed ixi environmental
supply.
review.
6..
Fire control and suppression
6.
In approving developments, water
6.
Review fire protection standards ,For
�,s often restricted by anade-
{water
supplies should be fully coni-
individual and community water sy-I tclis
ciliate supplies,
sa.dare.
serving new developments.
TABLE 111-8. E1RD HAZARD SLAB-NLENMNT
FINDINGS POLICY IMPLEMENTATION
Marty residential areas of 7. Require water connection to 7 Adopt building dole requirements
groater risk have swimming pool for fire purposes, for such connections.
pools. -
8. Access to fires by emergency 8. Ensure that road access for 8. Develop standards for widths, graces,
equipment is cften limited by new development is adequate and curves of new roads to permit
inadequate roads, for fire protection purposes. passage andmaneuvLzring of emergency
vehicles. Require multiple acces,
wl ave feasible.
9. Fire repG-vt and response times 9. Require or promote the easy 9. Develop and implement a consistent
ate often delayed b ancon- identification of stroats and street naming and house numbering
ofteny identification
and deficiencies in developed properties. system for the entire County. Require
street naming and house numbering all names and numbers to be clearly
visible,
J.O. Some human activities and land 10'. Regulate as necessary (those 10.-Cunsider' adoption of uniform dire code
fesshavcausing fires a high potential activities and uses with a, or Codification thereof.
ohave high fire potential.Mlet�
11. In higher than average fire 11. Regulate use of certain 11. Adoptbui:l:ding, code regulations for
hazard areas, certain types of building, materials in areas of roofing acid siding materials in firm
building material;, are less higher than average fire hazard. hazard areas
flamable.
12. Accumulations of shrubs and 12. Promote controlled burning- in 12. Develop and adopt standards for
debris constitute a fire hazard, hazardous meas: controlled burning,
elements affthecatieraloflthe findings,, p y, p of the scenic highways, noise, fire, and geologic
otic .and implementation
Supervisor RTQHTEK Supervisor
k
Table 11-2 SEISMIC SAFETY ELEMENT
FINDINGS
POLICY IMP1,I MNNTATION
1.
Butte County is in an area of known
1.
Inform the public of current
1.
Approve and publish this plan element.
faults and recent seismic activity.
estimates of seismic hazard in
Keep the information up -to -elate..
all parts of the County.
2.
The only known active fault in Butte
2.
Take into account all known,
2.
Consider the most recent tnformatton
County is the Cleveland Hill fault
seismic information inmaking
on seismic hazard in all zoning and
near Oroville'. AA number of faults in
land use decisions. Avoid
subdivision decisions.
or near the County should be considered
locating schools, hospitals
potentially active. The proximity of
and similar uses in known
the San Andreas fault- system is
fault areas.
generally significant in. evaluating
seismic risk in the County,
3,
The area around the Cleveland Hill
3.
Review the policies and criteria
3.
Exercise approval authority with respect
fault has been designated as a
established by the State Mining
to all real estate development and
Special. Studies Zone under the AlquiSt-�
and Geology Board within the
structures for human occupancy within
Priolo Act, effectuve January 1, 1977.
special studies zone and consider
the Special Studies Zone, as provided
(Chapter 7.5, "Division 2 California
implementation.
by State law,
Code.)
4.
Portions of the Sacramento Valley have
4.
Consider liquefaction potential in
4.
Require appropriate design of structures
a generally high potential for
making land use decisionsi
susceptible to the effects of liquefaction.
liquefaction during a major earthquake.
Table 111-1. G OLOGIC HAZARD SUB -ELEMENT
POLICY
IMPLEMENTATION
BINDINGS
1.
The identification of r,aologic
1.
Inform the public of geologic
1.
Approve and publish the hazard maps
hazards is in the public interest.
hazards.
in this plan element, recognizing
that these maps are generalized and
that each project and each site must
be judged on individual merit.
24
Geologic hazards limit land
2.
Consider; geologic hazards in
2.
Continue to implement guidelines
uses in high hazard
development capabilities.
development of Land Use, Ilousi.ng,
restricting
Lstablish limits on the
Circulation, Conservation, and
areas.
Open Space elements.
density and type of development
permitted in high hazard areas.
3.
The ride of landslides is greatest.
3.
Consider landslide potential of
3.
Where appropriate, investigate land -
in areas with slopes over 15%, weak
private development and public
slide.Potential of proposed development
findings in environmental`
rock, and high rainfall:
facil.ities,in areas rated 4 and
and present
review subdivision review.
5 on Map I1I-1;.
,and
4.
The removal of surface material by
4.
Consider erosion potential of
Where appropriate, investigate erosion
rain and water varies by slope, soil,
private development and public
potential of proposed development and
findings in environmental review
vegetation, precipitation and
facilities in areas gated high
present
development. It is greatest in
and very high on Map 'III -2:.
and subdivision review.
areas of granitic rock.
S.
Ground surfaces can sink and cause
5,
Protect against subsidence from
5.
Monitor sinking as necessary. Consider,
in review of proposed
signi.fi,cant damage in areas where
ground water withdrawal and oil
withdrawal. Oppose State
subsidence potential
withdraw216. Support projects to bring
there is extensive withdrawal of
ground water,,oil, and gas.
and gas
plan to pump our ground water out
surface waters into Butte County wherever
with deep wells.
_
possible.
Table 111-3. FIRM HAZARD SUI34M Mf+M` ,
FTNDIX S
I. Fire haAard is a problem for all areas,
but is more pronounced in certain foot-
hill and mountain areas,
2. As population gruvs, the potential and.
incidence of .fire also Crows.
ML C7
1. Make protection from fire hazards a
consideration in all planning, regulatory,
and capitol improvement programs, with.
special concern for areas where :L'ixe
hazard is more pronounced.
2. County should attempt to improve :fire
protection as population grows.
TPV1` EMENTATI ON
1. Consider fire hazards in all land use and
zoning decisions, environmental review, sub-
division review and the provision of public
servioeS,
2. Continue to require subdivisions and ria or new
developments to make contributions to fire
protection services on which they relay, an a
condation of approval.
3.
Vegetation is the critical ,factor in
3.
Use Vuel.brakes along the edge of developing
3.
Require fuelbroaks where feasible in areas
fire spread.
areas and in high .fire Hazard, areas.
where fire, hazard is high.
C,..
Tire protection facilities and services
!.,
Upgrade fire service where economically,
4.
Promote formation of voluntary tire companies
are marginal in some areas of the e County,
feasible:
in remote areas. Construct; additional
facilities and services as desi.rud by area
residents and as economically feasible.
5.
Development in watershed areas can
5.
Carefully evaluate development in water-
5.
Prepare zoning clans for critical watershed
affect community water supplies.
shad areas to determine 'their effect on
areas. Consider possible effect to watershed
community water supply,
in environmental review.
6.
Fire
control. and: suppression is often
6.
In approving developments, eater supplies
6.
Review fire protection standards for individual,
restricted by inadequate water supplies.
should be fully considered.
and community water systems serving ne��.
..
developments:
7.
Mari;j ros.i,dentIalo areas with high .fire
7.
Require water connection to Pool for fire
7.
Adopt building code requirements for sucii
r.,sk have swimming pools.
purposes,
connections.
Y
Table :CTS-- FIRE HAZARD STIB-BT,)rMEN`I'
I TNDING,S
POLTCY
TIV);S-MENTATION
8.
Access to fires by emergency equipment
8.
Ensure that
road access for newt devvel.opmerit
8.
Develop standards for road widths, grades,
is often limited by inadequate roads,
is adequate
for fire protection purposes,
and curves to permit passage and maneuvering
of emergency vehicles, Require multiple
access where feasi.bl e,
Fire r oport and rosponso (,arms arra Often
9i
Require or
promote the easy identification ion
9.
Develop and ;implorri int a nonsi atent, sfrorat
delayr;cl by inc;onsi.ste nc.los and defiolencies
of streets
and developed properties.
nfauui.ng and house numbori ng system for the
In streat naming and house numbering.
entire County; Require all, names and numbars
to be clearly visible,
10.
Some human_ activities and land, uses have
1.0.
Regulate as
necessary those activities and
10.
Consider adoption off' uniform fire crude or
a high potential for causing fires.
uses with a
high fire potential
modification thereof.
l.l.
Tn higher than average fire hazard areas,
11
Regulate use
of certain building materials
11.
Adopt bujl.din6 code r,yf,alations Por roofing
certain types of building materials are
in areas of
higher than average fire
and siding .materials in ['a go hazard aveas.
:less fl.amable.
hazard
12.
Aoc?.:witilations of shrubs and debris
12..
Promote controlled burning in hazardous
1.2,
De ,slop andadopt standards Por colltrollpd
constitute a lire hazard,
areas,
burning.
A
Table IV -6. NOISE, ELEMENT
s
i
i
i
I
objectionable noise from transportation
1.
Endeavor to maintain an acceptable noise
1.
Consider adopting the State's Vwlol
facilities and stationary sources can
environment in all areas of the county.
Community Noise Ordinance. or a mMification
have a significant impact on public health
thereof,.
and welfare
2:
Some aspects of transportation related
2.
There economically and otherwise fPasibl.e,
2;
Study State and Federal regulations for
noise can. be controlled by the County.
control the sources or transportation
reducing transportation noise. Consider
noise to maintain acceptable levels.
noise in the location and design of County
roadsi Locate aircraft ('light paths away
from developed areas where feasible.
3.
Railroads and h!.ghvrays can cause a signi-
3..
Discourage future railroads and highways
3.
Consider noise sources in review of zdniig
ficant noise problem near developments
and other noise sensitive acti.v.i.t;:ies near
and subdivision proposals.
residential developments.
4.
Development near aircraft flight paths
4.
flan for airport development and discourage
4.
Locate noise -sensitive uses away f rcm airports.
subjects people to ob ectyaonabl.e noise
noise -sensitive activities near airports.
Prepare specific Airport Environs flans for
and threatens future airport; operations.
Chaco and Oroville airports. Encourage comPa.tr-
ible uses around airports
5.
Son:eYp es or recreational activities
Control recreation_ .activities that have the
5.
Place limits on levels of W11plif'sed sound and
rrrake. objectionable noise,
potential to causeobjectionable noise,
the time and location of outdoor concerts, cute
and motorcycle races, and similar noise activities.
Identify locations for such activities that are
compatible' with the public health, safety, and
welfare.
T'a'le 1 V6.. NOISE ELEMEN't'
]J'xNDINCS
POLIO
6.
Stare legislation requires noise insulation
6. Provide 60 dB noise contours around all
6.Develop 60 dB noise contours around major
of new multifamily dwellings constructed
major eo-wces.
sources where this information is not
within the 60 0 noise exposure contours.
presently available.
7i
Noise problems cross City, boundaries.
7. Cooperate with tho incorporated cities
7. Exchange noise contour information. Atte,�.pt
-to resolve mu teal. noise problems.
to develop compatiblo noise control programs,
As -the County grows and activities change
g. Kee the Noise Element current with
Keep
8. Monitor changes in 'noise levels. Update noise
the noise environment will, also change.
changing cood,i.ti.ons.
contour c.ata.
Table V-1, SCENIC HIGIVAY ELNMEN
k
FINDINGS
POLICY
IMPLMENTATI'ON
1.
Butte County has many ;areas of
1.
Protect valuable scenic areas
1.
Develop a system of scenic highways.
picturesque natural landscapes.
for enjoyment by residents and
visitors.
2.
Official State designation of
2.
Consider official State designs-
2.
Follow procedures in Appendix P for
scenic highways requires various
tion of scenic highways.
designation of State scenic highways.
County actions.
3.
Scenic corridor boundaries include
the "view
3.
belineato corridors to include
34
Evaluate possible scenic corridors,
from the road."
scenic values according to
Solicit citizen participation. Prepare
criteria in this plan element.
"Scenic Highway Report" for each
corridor.
4.
Development within a scenic highway
4.
Consider scenic valuas in the
4-.
Require Planning Commission annual
right -o£ -way can have signif.cant
design and improvement of the
review of major road projects to
impact on the view,
right-of-way,
include concern for scenic values.
5.
Numerous vehicle 'access points along
5.
Where possible, minimize dr!veway
5.
Utilize existing access where feasible.
scenic highway:, can interfere with
and road access to scenic high
Review encroachment permits for
driver safety and comfort, and
ways, considering economics and
necessity.
roadside beauty.
engineering design.
6.
The unsightly view of utility lines
6.
Locate and design £utur,, utility
6.
Review the location and design of
and certain structures may be miti-
structures to improve the view,
future major transmission lines. Require
gated by inconspicuous siting and
where economically feasible•
the least conspicuous location of
pleasing design.
distribution lines, whore there is
reasonable choice.
MMW�
iH .
I ONE
'Cable V-1. SCENIC tll:GWA'Y ELEMENT
FINDINGS
POLICY
IMPLEMENTATION
7. Protection of scenic corridors is
7. Consider compatible land use
7. Amend Zoning ordinance to implement
largely dependent on local land
patterns in scenic corridors..
County policyi
use regulations.
B. An effective scenic highways program
8 rromote the county scenic highway
B. Indicate routes on public maps and
requires active local support,
program.
plans. Place "poppy" signs on
including the support of affected
adopted routes. Encourage advertising
property owners,
by Chambers of Commerce and others.
Seek citizen participation in all
aspects of the program,
9. Designation of a scenic highway can
9. In conside,ing any road designation
Consider aconomic impacts on property
affect the use and value of adjacent
as a scenic highway, a public hearing
affected by a scenic highway
property.
shall be held and all adjacent
designation.
'
property owners shall be notified
of the public hearing by mail:, in
addition to general notices published
in a newspaper of general circulation.
BOARD OF SUPFR",`ISORS
Robert Winston District '1
Bernard Richter w District 2
Jack Madigan - District
Bertha Moseley District
Robert Lemke - District S -
PLANNING COMMISSION
George Gilbert - Dist'L°ict '1
Louis Camenzind., Jr. - District 2
Velma Smith District 3
Wilbur Moore District 4
Priscilla Hanford - District
William Thebach - City of Biggs
Frank Watters - City of Chico
Jack Watson - City of Gridley
Raoul LeClex'c - City of Oroville
GENERAL PLAN CITIZENS ADVISORY COMMITTEE
W illiwa Geddis -- District 1
John Stutz - District
Larry Armstrong District 3
Al. Appleman -- District
William Holding District 5
COUNTY STAFF
Clifton Mickelson - County Administrator
Daniel Blackstock - County Counsel
ClayCastleberry Director of Public Works
Lawrence Lawson Planning Director
Bob Gaiser - Planner 11
Jay McXeeman -- Planner.1
CH2M MILL
Richard S Ivey w Project Director
Bradford Blandin 81 inior Planner
William A. Bl,osser - Senior,Planner
Larry C Amans - Civil. Engineer
W. Bruce Landrum Noise Analyst
Monte K. Weaver -- Engineering& Geologist
ra
no
Soction i
INTRODUCTION
This document cor ta,i,ris four of the nine mandatory General
Plan elements required by Article e 5, Chapter 3, of Title 7
of the California Government Code. The four elements deal
with Seismic Safety, Safety, Noise, and Scenic Highways.
They are presented 'here in draft farm for public review and
discussion before final revision, approval by the County
Planning Commission, and adaption by the Board of Supervisors,
Thc-tinaaral--�ao-l:es-�ha za--xe etkieI,,iooa
7?h�-.-to��.�--e1.�me�.s�.nau,��ieorY--�e];���er�•�-�{.>�:;:aw�°�tcra�°�ngo;ng
set,. iM c i, iens - The County has already
adopted the other five elements of the .General„ Plan dealing
with land use, circulation, housing, conservation, and open
space.
Fp
Following adoption, these elements will become offioia
�'',..folicy statements of Butte County. �' �kxcss-pvi�.ores�wz l be•
in��g;� •s,-��p�P.x,.�,� @�..,a,x���..�..tk�.�;�».r Conera� P-�azs�e"Z�ment�...
and-�-be��ise�-moo_..rev-��p.�.o:oo�dn;att�c�.�.plans�ancl ,.p�o��°aitrsR�s~�the
pl- ng --pr e �un olds• Xeeping the plan up-to-date
i s a,
w � r5 p5 gr tinasry�-end-
continuing responsibility of the County` Planning Commission
and Board of Supervisors.
The State BIR Guidelines require that an
Environmental Impact 'Report be prepared for rai;-P-ian.
..e-rr�e General plan elemento. The Drat Environmental
Impact Report for the Seismic Safety, safety, Noise, and
Scenic Highway elements is contained in AppendiX A. The
contents of the Draft Ern reflect the -bl;'-nad--ate- �general /
nature of theA*rlParr-1men►"pvSG!
z�1pvt
Titer
page
A.
GENERAL
1. State Requirements
II -1
Planning Relationships
11-2
3. Alquist-Priolo Special Studies Zones
11-2
B.
OBJVCT1V1
11-3
C.
PHYSIOGRAPHIC PROVINCES
11-3
1. Sacramento Valley Province
XI -3
2. Sierra Nevada Province
1I-4
3. Cascade Range Province
1IR5
D.
GENERAL GEOLOGY
it -5
E.
SEISMIC HISTORY AND FAULTING
I1-5
F.
POSSIBLE EARTHQUAKE SOURCES
11-8
1. Active Faults
II -g
a, Cleveland. Hill. Fault
11-3
bo Midland-Sweitzer Fault
II -10
0. San Andreas Fault Zone (North Section)
Ii -11
d. Hayward-Calaveras Fault Complex
II -1 -IA -
e. Russell Valley Fault
11-12
f. Last Chance, -Haney Lake Fault Zones
Z. Potentially Active Faults
11-13
G.
FAULT ZONE EVALUATION
11-13 ,
H.
15REDICTED EFFECTS OF EARTHQUAKES .
11-16
1. Ground Shaking
II -1&0
2. Liquefaction
II - TIT �"
3. seiches
11-20
4. Landslides
-
5. Dam Safety
11-21;r
.,-1
POLICIES
11w21="`
TABLES
Title
page
11-1
Fault Zone Evaluation
xt-14.a
11-2
Seismic Safety Element (Findings
Policies, and implementation)
Section 11
9 SP�xSMXCI SAFBTY PM=NT
A. GMERAL
State Requirements
Section 65302(f) of the California State Code requires each
county to prepare a Seismic Safety Element. as part of the
County Genera. Plan. 'This element consists of
"...an identification and appraisal of seismic
hazards such as susceptibility -to surface ruptures
from faulting, to ground shaking, to ground failures,
or to the effects of seismically induced waves
such as tsunamis and sei,ches .
"..wan appraisal of mudslides, landslides, and
slope stability as necessary geologic hazards
that must be consideree simultaneously with other
hazards such as possible surface ruptures from
faulting, ground shaking, ground failure, and
eismicalxy induced wave."
'T'!�e r� e rel S�(�f�� �r 1r' l,� �C�"� �(✓!?� qr 1�;+ c��'% �,r sr � �? �' �. �1 �'��'<r?� >� ���;{ so w � k ,� j�
fi�
that the !dentif:ication
of seismic hazards should include: (1) general structural
geology and geologic. history, (2)' Location of all. active
and potentially active faults, with evaluation regarding
past displacement and the probability of future movement,
,.
(3) evaluation of slope stability and soil subject `to liquefac-
tionand differential subsidence, (4). assessment of the potential
for occurrence and severity of damage in ground shaking and
amplifying effects' of unconsolidated materials, (5) identifi-
cation of areas subject to seiches and tsunamis, and (6) maps
dentfyiig the location of the above characteristics.
2. Planning Relationships
The Seismic Safety Blement provides information that relates
directly to the preparat-ion of the Lana Use, Housingt Open
Space, Circulation, and safety elements.. It is impottant
to recognize, 1--owevere that the data available for this pur-
pose is inherently incomplete.
r.
Land use clecisir_,as must be made in the light of the very
best information when publin safety is the issue. Thereforee
this element of the General Plan for butte County carries
with it the assumption that available data on seismic risk
is desca:ibed or referenced here, and that new information
will be added as it becomes known.
The application of this information to specific land use
decisions can only be made case by case. in many situations,
the information here is only a starting point for the detailed
geologic investigations that are warranted by the circumstances.
These will ordinarily be undertaken by the sponsor of a project
in preparing an environmental impact report or an engineering
feasibility study.
3. Alquist-Priolo Special Studies Zones
The California Public Resources Code Division 2# Chapter 7.5t
sections 2621-2625t concerns the Al,quist-Priolo Special Studies
zones dot. The he purpose of the act is:
.to provide for the adoption and administratioi,
of zoning laws, ordinances# rules, and regolations
by cities andcotntios in implementation of the
general I plan that is in effect in any city or
County ... to provide policies.and criteria to assist
citio8t countie,so and state agencies.in the exercise
64 their responsibility }.o provide Coe I lie public
sa,f'oty in hazardous fault zones."
Site specific geologic roports axe: recluirecY, T-r Local approval
of new real estate developmi_-rit-�; and certain tru.ctures J:or
human occupancy which are loci; t:ec1 in the zDe--i Axl. Studies
Zone. The act does not appl, to any develo,ent or structure in
existence prior to January 1, 117
B. OBJECTIVE
The basic objective of the Seismic laffal:y Elem f it is to pre-
scribe
scribe measurer to reduce loss of litc1, injury, damage to
property, and economic and social di .�, aption resulting from
earthquakes,
C. PFYSIOCRAPIC PROVINCES
Butte County includes portions of three major physiographic
provinces. The western one-third of the County is in the
Sacramento Valley province, which is under:ain by sedimentary
rocks 15,000 feet thick, with 100-200 feet of recent sediment
overlying the rocks (Tertiary Formations)The eastern two--
i
thirds of the County is in the Sierra Nevada province arid.. is
underlain by igneoas and metamorphic rooks The portion, of
the -County near Janesville and lnskip lies partly in the
Cascade Flange physiographic province. The Cascade Range
province is represented by a chain of volcanic cones where
there are extrusive volcanic flows and pyroclast.ic sediments
along with mudtlows of volcanic and pyroclastic origin.
1. Sacramento Valley Province
The Sacramento Valley is a° nearly level alluvial plain,
separated gcologically from. the San Joaquin Valley by a
buried northeast -trending fault, in the vicinity (if Stockton.
On the northt the valley torminates at tho XIamath Mountain
foothills. The val icy is draineO by the Sacramento River,
which passes through flood basins that inellide the Butte
Basin west of OrovIlle. Both natural and man-made levies
border the Sacramento River through much of the lowlands.
Recent alluvium underlying the greater part of the valley
intermingles with numerous stream deposits of silt, sand,
and gravel which were deposited by streams from the hills to
the east. These recent deposits consist mainly of :reddish,
sandy clay and black humus topsoil overlying unconsolidated
sand, silt, clay, and gravel, The valley alluvium deposits
increase in thickness from cast to west, ranging from only a
few inches along the foothills to more than 200 feet near
the Sacramento River, The ground -water table is commonly
high (within 10 feet of the surface) throughout the lowlands.
Pleistocene deposits of poorly consolidated, deeply red
stained gravel, sand, silt, and clay are found as -terraces
along many of -the stream channels near the eastern edge of the
valley. The terraces were apparently formed a.8 ancient
flood plains of the Feather River and other streams during
glacial perirj8.
2. Sierra Nevada Province
The Sierra Nevada is a westward tilted fault block of great
magnitude* The block has a high, multiple -fault scarp face
on the east front and a more gentle, kault-bound west front
which disappears under the sediments of the Sacramento
. valleyThe bedrock of the Sierra Nevada province consists
commonly of Paleozoic and Mesozoic metasediments and volcanic8
intruded by a Mesozoic granitic batholith. The Sierra
Nevada Mountains form the major portion of the eastern half
of Butte county.
11-4
W
Along the western slope of the Sierra Nevada range, Tertiary
sediments, volcanics, and isolated areas of upper Cretaceous
sodiments of the Sierra Nevada foothills dip westward, beneath
the Sacramento Valley. The Sierra Nevada Range terminates
abruptly in the north where it disappears beneath the younger
Cenozoic volcanic rocks of the Cascade Range. Highly timefa'-
morz.,osed sedimentary and igneous racks lie along the west
and northern edges of the Sierra Nevada.
in Butte County the western foothills of the Sierra Nevada
gradually merge into -the Sacramento Valley, The foothills
are comprised commonly of younger Tertiary sediments, ex-
trusive flows, volcanic mudflow material, and old alluvial
sediments. One of the dominant features of the fcot.hills is
the Tuscan monocline, a flexing of surface rocks which
trends northwest between Chico and Red Bluff, The average
dip of the surface east of this line of flexure is 2--3
degrees. West of this line, the dip changes and averages
from 5-5 degrees; continuing at -this angle until the surface
rock penetrates the valley alluvium, The Tuscan monocline
is'a linear feature similar to -that of a fault.
3 Cascade Range Province
The Cascade Mange extends from Washington to northern Butte
CoUnty. Mount Lassen, one of the few active volcanos in the
continental United States, lies within this province approxi-
mately 23 miles north of the County. Late Cenozoic extrusive
volcanic rocks comprise the mass of the Cascades. in Butte
County, these roofs overlie portions of the sediments of the;
Sacramento Valley and -the rock of the Sierra Nevada,
D. GENtRAL GEOLOOY
The loothil..ls and mountains of the Sierra Nevada and the
Sacramento Valley are the result of a complex geologic
history,, some aspects of which are unclear even now.
ll_�5
The old bedrock, or zeta,morphic base rock, series of t1iz
Sierra Nevada has been sub j eoted to an in -tense deformation
resulting in dynamically metamorphosed rocks. Intense
folding and faulting have produced an area of steep, commonly
eastwardl.y dipping, northwesterly striking bedrock series
through the center of the Sierra Nevada. This bedrock
series Is hound on the east and wast by zones of active and
potentially active faults.
In -the eastern portion of the County, granite has intruded
into the older metamorphic bedrock. These intrusive's may
extend to the west under the meta,morphics at a relatively
shallow depth.. Contact between the granitic intrusives and
metamorphics is In many cases marked by seismic evidence
which indicates faulting may be continuing today,
on the west, the sediment of the. Sacramento Valley overlaps
the rocks of the Sierra Nevada foothills These sediments.,
for the most part, are relatively flat and dip gently west
to southwest with only minor faultincr and folding parallel
to the structural trend of the valley and the Sierra Nevada
range.
E SEISMIC HISTORY AND PAULTING
Butte county and the surrounding area,are located on the
western portion of a faulted and d:ownwatped series of ancient
metamorphic; rocks of the Western Sierra Nevada Mountain
Range. Granitic rocks associated with Mesozoic thrust
faulting are "Located in the eastern portion of the County.
In the western portion, of the County, gently folded younger
9
bedding an _most, places. The formations and geologic structure
Of the. County appear 'to he Controlled or strongly modified
by Cenozoio faults extending along the western portion of
the Sierra Nevada Mountains and trending north-northwest
along with the Big 'Send, Camel. Peak, Dogwood Peak, Rich Bar;
M
and Melones faults, most of which lie to the north and east
' of butte County in the area of granitic intrusions (sea
:Map 11-1). Most Sierra Nevada faults ,are a combination of
strike slip and thrust movements, (Bailey, Ceo10 EY—0—f
Northern California, California Division of Mines and Geology.)
Movement on the Cleveland Hill fault on 1 august 1075 was
apparently the result of crustal strain developed in the
foothill shear zone, The Cleveland Hill fault, located
about 5 miles southeast of Croville, trends north-northwest
and is approximately 10 miles Long. It is presently the
only known active fault within Butte County, (Sherburne and
Fauge, oroville, California Earthguake, 1 August 1975,
California Division of Mines and Geology,)
In the northwest cornier of Butte County near Chico there are
a series of shot, north -northwest -trending faults similar
to the Cleveland Hill fault. These faults appear to be an
extension of the Bear Mountain Fault or Foothills Shear Zone
(see Map 11-1) Minor seismic activity has occurred rn the
ares, of these short faults; however, other geologic gvidence
indicates these faults are not active.
Approximately 5 miles west of Butte County there is a north -
trending fault system ki own as the Willowsfault (see Map II -1).
This fault is approximately 40 miles long and displaces
Cretaceous sediment in the Sacramento valley. it does not
appear to displace• surface sediment and has been mapped
pritOipally by geophysical methods. However, there have
been enough historical seismic events in the vicinity of
11-7
,this ;baulk to conclude that it should be considered potcntial.ly
active. (Uennings, g California
Division of Mines and Geology.)
The Coast Stange Mountains west of Butte County have a geo-
logically complex 10-f-ory. A major complicating factor is
the San Andreas fault, located on the western boundary of
the Coast Range province. Although the existence of this
fault has been well known since it was established as a
source of earthquakes in 1838, 1857, 1941, and 1906, it has
only been in the last 15 to 25 years that geologic evidence
has been sufficient to fully document its importance. It is
now well known that the San Andreas, and the faults related
to i.t,is not only a major source of earthquakes but is the
contact of one of the _six major geologic pates bf the
earth's crust, The San. Andreas and the related faults have
a major impact on the seismic safety of Butte County.
'Jennings, Fault Map of California, California Division of
Mines and Geology, and Bailey, Geology of Northern California.,
California Division of Mines and Geology.?
F. POSSIBLE BARTHQUAKt SOURCES
The historic earthquakes of California have usually originated
along faults which existed prior to the earthquake. An
active -fault is generally considered any fault which has
undergone displacement of sufficient geologic recency to,
:suggest that there is a potential for displacement in the
reasonably near future. In general engineering practice, a
fault is considered active if there is displacement wic.hin
Holocene deposits regardless of. datable evidence.
Faults are classified as potentially active based upon
h3i8tor'ic, geologic, and seismologic evidence. Historic
evidence may include manuscripts, news accounts, personal
diaries
and boobs which describe past earthquakes. Gelogia
Il -8
I
evidence of potentially active faulting may incl,udo dig -
Placement of geologically young :.Corma,tions . Accurately
determined earthquake epiconters, which can be assigned to
individual faults with a, high degree of confidence, . con-
stitute Seimologic evidence suggestive of possible fault
activity, (Krinitzsky, State of the Art of Assess
BarthqRake Hazards in the United,states, V, S. Army
Engineers Waterways Experiment Station.)
Those faults having historical or recent geologic ao.Eivity
are classified as active; faults located in areas of histori-
cal seismic activity are classified as potentially active,,
and all other faults are classified as potential, activity
unknown.
1. Active Faults
a. Cleveland Hill Vault
The only known active fault in Butte County is the Cleveland
Hill fault, where activity on 1 August 1975 resulted in the
Oroville earthquake. This earthqtake has a Richter,magilitude
of 5.7 and resulted in about 2.2 miles of surface cracking
along the western flank of Cleveland Hill. Reports by the
California Division of Mines and Geology indicate that the
ground motion at Gridley, which is located on valley sediment,
was approximately 0 times accelcl,.,ation of gravity. Similar
motion was experienced.in Oroville, and considerable struc-
tural damage occurred. The earthquake was felt in Chico,
but there was no recorded damage. Fault movement was both
normal and strike -slip., Studies of lineaments from Skylab
photographyt the earthquake focal coordinate, plane, and
topography indicate that this fault could have alength of
11 to 15 miles with a maximum credible earthquake of 6.5 to
6.7 -Richter and a maximum bedrock acceleration 1 to 2 miles
from the fault of 0.45 to 0.658 A._Map of
Maximum Bedrock Aocelera•i for s From Barthaua, os in C'alLf_Orui,a)
Historically, tither, earthquakes have occurred : n Butte
County; however, none of these have resulted in recorded
strucutral damage or ground motion as great as that of the
1975 Orovill.e earthquake. (Sherburne and Hauge, Orovill e' ,
California Earthquake,tclust 1, 1975, California Division
,H
.. -, —
of Mines and Geology.)
on January 1, 1977, a 4-1/2 mile long portion of the Cl.evelagd
Rill fault trace was declared a Special Study Zone by the
State of California. The location of the Cleveland dill
fault and the Special. studies Zone is shown in Map Ix -1.
Copies of the official, Map showing the location of the zone
and requirements pertaining to the zone are on file at the
Butte County Planning Department.
b Midland- Sweitzer Fault
The 80 mile -long Midland-SWeitzer fault is located approxi -
'mately 90 miles south-southwest of Butte County. This fault
is considered active and has caused historic earthquakes of
Richter magnitudes between G to 5.9.
Greensfelder (1973) estimated that the Midland-Sweitzer
fault -is capable of producing a magnitude 7.0 earthquake,
probably based on, the oceurence of two strong earthquakes in
-the area in 1892. The first of these earthquakes had an
intensity of X on the Modified Mercalli scale in Solano
County, and was felt as far away as western Nevada. The
second earthquake occurred in the Winters area and had an
intensity of Modified Mercalli IX,i Damage was reported as
Eat away as Grass valley and Lodi. There is some speculation,
as to the exact l.ocatio- of the earthquake epicenters and
some question it they actually occurred on the Midland-
Sweitzer .fault. However;, since the 1892 earthquakes originated
on a fault within tthis same general area and at a consider-
able distance from Butte County, the precise identity of the
fault is not
significant, at this time, (Bail.ey� Seismic
Safety Information, and Jennings, Fault Map,of California,
California Division of Mines and, Geology.)
c: San Andreas Fault zone (North Section)
I
The San Andreas fault is one of the most active in California.
The fault is move than 650 miles long and extends from
Shelter Cove to the Salton SeaCeologic evidence indicates
that the total, strike -slip movement along this fault has
been on the order of 450 miles and could possibly be as
great as 750 miles. Significant historic earthquakes with
surface rupture have occurred along the San Andreas Zone in
i
1838, 1857, 1901,. 1906, 1922,, 1934, and 1966. The effects
of the 1906 earthquake; measured at 8.3 Richter, were described
`r in the State Earthquake Investigation Commission report,
California Earthquake of April 18, 1906. That report indicates
that the Modified Mercalli intensity of the 1906 earthquake
was between V and VI in western Butte County and IV to V in
eastern Butte County. flAt its nearest point, the San Andreas
--)
b, fault i.s located approximately 95 mile$ west of Butte County.
i. .
d Hayward -Calaveras Fault Complex
The >tayward-Calaveras fault complex is considered by the
Division of Mines and Ceo.Logy to be a branch of the San
Andreas fault. The most active portion of the Hayward faint
is approximately 445 miles long and extends from San Pablo.Bay
to the Warm Springs district of Tremont. It, apparently
joins the Calaveras fault in the vicinity of San Jose
Extensive ground rupture occurred along this fault during
major earthquakes in 18.36 and again in 1$68. Ness the
fault, these earthquakes had a reported maximum, Modified
Mercall.i intensity of ZX to X. Widespread damage was
II
reported. The Hayward fault has also been the focus of
other damaging earthquakes. Historical accounts do not
describe the effects of these earthquakes In the vicinity of
Butte County; howevor. the 1860 earthquake is reported to
have caused strong fluctuations in the water level in the
Sacramento River near Sacramento and in a slough near
Stockton.
Strang earthquakes have occurred along the, Calaveras fault,
an apparent continuiatrion of the Hayward and Sari Andreas
fault system. The strongest recorded earthquake: attributed
to the Calaveras fault was in 1861 when there was a Modified
Mezcal.li intensity of VXII near the fault.
e. Russell. Valley Fault
The Russell Valley fault system is located in the easternmost
Sierra Nevada frontal fault system. The fault trends north-
northeast and is approximately 50 miles east of .Butte County.
Movement on this fault apparently resulted in the 1966
Truckee earthquake. The reported magnitude of the 1966
earthquake ranged between 5.4 Richter (U.S. Coast and Geodetic
Survey), and 6.5 Richter (California Institute of Technology)
The surface rupture of the fault was reported to be approxi-
mately 10 mile; long. The earthquake caused minor damage to
dams,' bridges', structures, and water wells in the Truckee
area:. (Ka,chadgori.an, et. al , Effects of t::e. Truckee
California, Earthquake of September 12, 1966, U.S. Geological
Survey.) The earthquake was felt in Butte County but no
damage was reported. The Modified Mercal.l.i intensity of the
1966 earthquake ranged from VIII near Truckee to IV near
Qrovillo.
t . Last Chance-goney Lake Fault Zone
The Last Chance -Roney sake fault zones are approximately 100
miles long a,nd trend north. --northwest along the California
Nevada, border. These: faults are apparently active and Have
resulted in earthquakes ranging .between S and 5.9 Richter,
3 Potentially Active, Vaults
Potentially active faults which could result in significant
ground motion in Butte County are shown in Neap 11"-1. These
include the Foothills shear zone, Sutter's Butte kaul,l.s,
Willows fault
"g
I�unna,an fault, Coast Range thrust zoner Big
Bead fault: zone:, Camel's Peak fault:, Melones-Dogwe0,.7 peak
faults and the Hawkins Valley fault. All of these faults
should be considered potentially active due to geologic,
historic, or seismic data. Other potentially active faults
may also exist within. the County.
C. FAULT ZONE EVALUATXON
Regional, geologic: investigations usually uncover only she
major faults of an area. Small faults can be easily misread
unless they have been previously mapped or outcrop at the
surface To account for small active faults that may exist
within an area, the concept of a "floating earthquake" is
suggested by Krinitzsky (State of the Art for Assessing
Earthquake Hazards in the 76ited States) A "floating
earthquake" is an earthquake with a specified maximum magnitude
that may occur anywhere at any time. This magnitude is
selected in relation to the highest recorded seismic event
in the area. Based upon this concept and the brief seismic
history :availa.ble for Butte
County; it,appears a "floating
earthquake" with a: magnitude of 6 'co 6.5 Richtercould be
assumed for central and eastern Butte County and 6.4 Richter
for :western Butte. County.
Table 11-1 contains an evaluation of the estimated seismic
effects in Butte County from earthqua;te activity in, the
fault zones discussed above. The principal regional sources