HomeMy WebLinkAbout416 ORDINANCE NO. 416
AN ORDINANCE OF THE CITY COUNCIL OF.THE
TOWN OF LOS ALTOS HILLS AMENDING CHAPTER 5 [FLOOD DAMAGE
PROTECTION] OF TITLE 7 [PUBLIC WORKS] OF THE LOS ALTOS HILLS
MUNICIPAL CODE REGARDING FLOOD DAMAGE PREVENTION
WHEREAS,the Town's current floodplain management ordinance is outdated; and
WHEREAS, the Town's floodplain management ordinance should conform to
federal regulations regarding floodplain management so that the Town can participate in
the nationwide flood insurance program.
NOW, THEREFORE, the City Council of the Town of Los Altos Hills does ORDAIN
as follows:
1. AMENDMENT OF CODE.. Chapter 5 [Flood Damage Protection] of Title 7
(Public Works]of the Los Altos Hills Municipal Code is hereby amended to read as follows:
CHAPTERS. FLOODPLAIN MANAGEMENT
Sec. 7-5.01 Statutory Authorization, Findings of.Fact, Purpose and
Methods.
Sec. 7-5.01.1 Statutory Authorization. The Legislature of the State of
California has in Government Code Sections 65302, 65560, -and 65.800
conferred upon. local government units authority to -adopt regulations
designed to promote the public health,safety,- and general welfare of its
citizenry. Therefore, the Town of Los Altos Hills does hereby adopt the
following floodplain management regulations.
Sec. 7-6.01:2 Findings of Fact.
A. The flood hazard areas of the Town of Los Altos Hills are.
subject to periodic innundation which results in loss of-life-
and property, health and safety, hazards; disruption of
commerce and governmental services,extraordinary public.
expenditures forflood protection and relief,and impairment'.
of the tax base, all of which adversely affect the public
health, safety, and general welfare.
B. These flood losses are caused by uses . that are
inadequately elevated, floodproofed, or protected from
flood damage: The cumulative effect of obstructions-in
areas of special flood hazards which.increase flood heights
and velocities also contribute to the-flood loss.
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Sec. 7-5.01.3 Statement of Purpose. Itis the purpose of this ordinance to
promote the public health, safety, and general welfare, and to minimize
public and private losses due to flood conditions in specific areas by
provisions designed to:
A. protect human life and health;
B. minimize- expenditure of public money for costly flood
control projects;
C. minimize the need for rescue and relief efforts associated.
with_-flooding and generally undertaken at the expense of
the general public;
D. minimize interruptions in use of property;
E. minimize damage to public facilities and utilities such as
water and gas mains; electric, telephone and sewer lines;
and streets and bridges located in areas of special flood
hazard;
F. help maintain a stable tax base by providing for the sound
use and development of areas of special flood hazard-so
as to minimize future blighted areas caused by flood
damage;
G. ensure that potential buyers are notified that property is in
an area of special flood hazard; and
H. ensure that those who occupy the areas of special flood
hazard assume responsibility for their actions.
Sec-.7-5.01.4 Methods of Reducing Flood Losses. In order to accomplish
its purposes, this ordinance includes methods and provisions to:
A. restrict or prohibit uses which are dangerous. to health,
safety, and property due to water or erosion hazards, or
which result in damaging increases in erosion or flood
heights or velocities;
B. require that uses vulnerable to floods, including facilities,
which-serve such uses, be protected against flood damage
at the time of initial construction;
C. control the alteration of natural floodplains,- stream
channels,. and natural protective baniers,which help -
accommodate or channel flood waters;
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D. control filling, grading, dredging, and other development
which may increase flood damage; and
E. prevent or regulate,the construction of flood barriers which
will unnaturally divert flood waters or-which may increase
flood hazards in other areas.
Sec. 7-6.02 Definitions
Unless specifically defined below, words or phrases used in this ordinance
shall be interpreted so as to give them the meaning they have in common
usage and to give this ordinance its most reasonable application.
"Accessory use" means a use which is incidental and subordinate to the
principal use of the parcel of land on which it is located.
"Alluvial fan" means a geomorphologic feature characterized by a cone or
fan-shaped deposit of boulders., graven, and.fine sediments that have been
eroded from mountain slopes,transported by flood flows,and then deposited
on the valley floors, and which is subject to flash flooding, high velocity flows,
debris flows, erosion, sediment movement and deposition, and channel
migration.
"Apex" means the point of highest elevation on an alluvial fan, which on
undisturbed fans is generally the point where the major stream that formed
the fan emerges from the mountain front.
"Appeal" means a request for a review of the Floodplain Administrator's
interpretation of any provision of this ordinance.
"Area-of shallow.flooding" means a designated AO or AH Zone on the
Flood Insurance Rate Map. (FIRM). The base flood depths range from one
to three feet; a clearly defined channel does not exist; the path of flooding is
unpredictable and indeterminate; and velocity flow may be evident. Such
flooding is characterized by ponding or sheet flow.
"Area of special flood hazard" - See "Special flood hazard area."
"Base flood" means a flood which has a one percent chance of being
equaled or exceeded in any given year (also called the "100-year flood').
Base flood is the term used throughout this ordinance.
"Basement" means any area of the building having its floor subgrade-i.e.,
below ground level - on all sides.
"Building" -see "Structure".
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"Development" means any man-made change to improved or unimproved
real estate; including but not limited to buildings or other structures, mining,
dredging, filling, grading,.paving, excavation or drilling operations or storage
of equipment or materials.
"Encroachment"means the advance or infringement of uses, plant growth,
fill, excavation, buildings, permanent structures or development into a
floodplain which may impede or.alter the flow capacity of a floodplain.
"Existing manufactured home- park or subdivision" means a
manufactured home park or-subdivision forwhich the construction offacilities
for servicing the lots on which the manufactured homes are to be affixed
(including, at a minimum, the installation of utilities, the construction of
streets, and either final site grading or the pouring of concrete pads) is
completed before the effective date of the floodplain management
regulations adopted by a.community.
"Expansion to an existing manufactured home park or subdivision"
means the preparation of additional sites by the construction of facilities for
servicing the lots on which the manufactured homes are to be affixed
(including the installation.of utilities, the,construction of streets, and either
final site grading or the pouring of concrete pads).
"Flood, flooding, or flood water" means:
1. a general and temporary condition of partial or complete
inundation of normally dry land areas from the overflow of inland or
tidal waters; the unusual and rapid accumulation or runoff of surface
waters from any source; and/or mudslides (i.e., mudflows); and
.2. the condition resulting from flood-related erosion
"Flood Boundary and Floodway Map (FBFM)" means the official map on
which the Federal Emergency Management Agency or Federal Insurance
Administration has delineated both the areas of special flood hazards and
the floodway.
"Flood Hazard Boundary Map" means the official map on which the
Federal Emergency Management Agency or Federal Insurance
Administration has delineated the areas of flood hazards.
"Flood'lnsurance Rate Map (FIRM)" means the official map on which the
Federal Emergency Management Agency or Federal Insurance
Administration has delineated both the areas of special flood hazards and
the risk premium zones applicable to the community.
"Flood Insurance Study"means the official report provided by the.Federal
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Insurance Administration that includes flood profiles, the Flood Insurance
Rate Map, the Flood Boundary_ and Floodway Map, and the water surface
elevation of the base flood.
"Floodplain orflood-prone area"means any land area susceptible to being
inundated by water from any source - see "Flooding".
"Floodplain Administrator" is the individual appointed to administer and
enforce the floodplain management regulations pursuantto Section 7-5.04.2.
"Floodplain management" means the operation of an overall program of
corrective and preventive measures for reducing flood damage and
preserving and enhancing, where possible,, natural resources in. the
floodplain, including but not limited to emergency preparedness plans,flood
control works,.floodplain-management regulations, and open space plans.
"Floodplain management regulations" means this ordinance and other
zoning ordinances, subdivision regulations, building codes, health
regulations, special purpose ordinances (such as grading and erosion
control) and other application of police power which control development in
flood-prone areas. This term describes federal, state or local regulations in
any combination thereof which provide standards for preventing and
reducing flood loss and damage.
"Flood proofing" means. any combination of structural and nonstructural
additions, changes, or adjustments to structures which reduce or.eliminate
flood damage to real estate or improved real property, water and sanitary
facilities, structures, and their contents (Refer to FEMA Technical Bulletins
TB 1-93,.TB 3-93, and TB 7-93 for guidelines on dry and wetfloodprooflng.)
"Floodway" means the channel of a river or other watercourse and the
adjacent-land areas that must be.reserved in order to discharge the base
flood without cumulatively increasing-the water surface elevation more than
one foot-Also referred to.as "Regulatory Floodway".
"Floodway fringe" is that area of the floodplain on either side of the
"Regulatory Floodway"where-encroachment.may be permitted.
"Fraud and victimization" as related to Section 7-5.06, Variances, of this
ordinance, means that the variance granted must not cause fraud on or .
victimization of the public. In examining this requirement, the City Council
will* consider the fact that every newly constructed building adds to
government responsibilities-and remains a part of the community for fifty to
one-hundred years. Buildings that are permitted to be constructed below the
base flood elevation are subject during all those years to increased-.risk of
damage from-floods,while future owners of the property and the community
as a whole are subject to all the costs, inconvenience, danger, and suffering
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that those increased flood damages-bring. In addition, future owners may
purchase the property, unaware that it is subject to potential flood damage,
and can be insured only at very high flood insurance rates.
"Governing body"is the local governing unit, i.e.county or municipality,that
is empowered to adopt and implement regulations to provide for the public
health, safety and general welfare of its citizenry.
"Hardship"as related to Section 7=5.06,Variances,of this ordinance means
the exceptional hardship that would result from a failure to grant the
requested variance. The- City Council requires that the variance be
exceptional, unusual, and peculiar to the property involved. Mere economic
or financial hardship alone is not exceptional. Inconvenience, aesthetic
considerations, physical handicaps,personal preferences,orthe disapproval
of one's neighbors likewise cannot, as a rule, qualify as an exceptional
hardship. All of these problems can be resolved .through other means
without granting a variance, even if the alternative is more expensive, or
requires the property owner to build elsewhere or put the parcel to a different
use than originally intended.
"Highest adjacent grade" means the highest natural elevation of the
ground surface prior to construction next to the proposed walls of a structure.
"Historic structure" means any structure that is
1. listed individually in the National Register of Historic Places (a
listing maintained by the Department of Interior) or preliminarily
determined by the Secretary of the Interior as meeting the
requirements for individual listing on the National Register;
2. certified or preliminarily determined by the Secretary of the Interior
as contributing to the historical significance of a registered historic
district or a district preliminarily determined by the Secretary to qualify
as a registered historic district;
3. individually listed on a state inventory of historic places in states
with historic preservation programs which have been approved by the
Secretary of Interior; or
4. individually listed on a local inventory of historic places in
communities with historic preservation programs that have been
certified.either by an approved state program as determined by the
Secretary of the Interior or directly by the Secretary of the Interior in
states without approved program, or
5. individually listed in the Town's General Plan as has historical
value.
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"Lowest floor"means the lowestfloorofthe lowest enclosed area,including
basement (see "Basement" definition).
1. An unfinished or flood resistant enclosure below the lowest floor
that is usable solely for parking of vehicles,building access or storage
in an area other than abasement area, is not considered a building's
lowest floor provided it conforms to applicable non-elevation design
requirements, including, but not limited to:
a. the wet floodproofing standard in section 7-5.05.1 C.3;
b. the anchoring standards in section 7-5.05.1 A7-
c.
;c. the construction materials and methods standards in
section 7-5.05.1 B; and
d. the standards for utilities in section 7-5.05.2.
2. For residential structures, all subgrade enclosed areas are
prohibited as they are considered to be basements (see"Basement"
definition). This prohibition includes below-grade garages and
storage areas.
"Manufactured home" means a structure, transportable in one or more
sections, which is built on a permanent chassis and is designed for use with
or without a permanent-foundation when attached to the required utilities..
The term "manufactured home" does not include a "recreational vehicle".
"Manufactured home park or subdivision"means a parcel(or contiguous .
parcels) of land divided into two or more manufactured.home lots for rent or
sale.
"Market Value" shall be determined by estimating the cost to replace the
structure in new condition and adjusting that cost figure by the amount of
depreciation which has accrued since the structure was constructed. The
cost of replacement of the structure shall be based on a square foot cost
factor determined by reference to a building cost estimating guide recognized.
by the building construction industry. The amount of depreciation shall be
determined by taking into account the age and physical deterioration of the
structure and functional obsolescence as approved by the floodplain
administrator, but shall not include economic or other forms of external
obsolescence. Use of replacement costs or accrued depreciation factors
.different from those contained in recognized building cost estimating guides
may be considered only if-such factors are included inn-a reportprepared by
an independent professional appraiser and supported by a written
explanation of the differences.
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"Mean sea level" means, for purposes of the National Flood'Insurance
Program, the National Geodetic Vertical Datum (NGVD) of 1929 or other
datum, to which base flood elevations shown on a community's Flood
Insurance Rate Map are referenced.
"New construction", for floodplain management purposes,. means
structures for which the "start of construction" commenced on or after the
effective date of floodplain management regulations adopted by this
community, and includes any subsequent improvements to such structures.
"New manufactured home park or subdivision" means a manufactured
home park or subdivision for which the construction of facilities for servicing
the lots on which the manufactured homes are to be affixed (including at a
minimum; the installation of utilities, the construction of streets, and either
final site grading or the pouring of concrete pads) is,completed on or-after
the effective date of floodplain management regulations adopted by this
community.
"Obstruction" includes, but is not limited to, any dam, wall, wharf,
embankment, levee, dike, pile, abutment, protection, excavation,
channelization, bridge, conduit, .culvert, building, .wire, fence, rock, gravel,
refuse, fill, structure, vegetation or other material in, along, across or
projecting into any watercourse which may alter, impede, retard or change
the direction and/or velocity of the flow of water, or due to its location, its
propensity -to snare.or collect debris carried by the flow of water, or its
likelihood of being carried downstream.
"One-hundred-year flood" or "100-year flood" - see "Base flood."
"Public safety and nuisance" as related to Section 7-5.06, Variances, of
this ordinance means that the granting of a variance must not result in
anything which is injurious to safety or health of an entire community or
neighborhood, or any considerable number of persons, or unlawfully
obstructs the free passage or use, in the customary manner, of any
navigable.lake, or river, bay, stream, canal, or basin.
"Recreational vehicle" means a vehicle which is
1. built on a single chassis;
2. 400 square feet or less when measured at the largest horizontal
projection;
3. designed to be self-propelled or permanently towable by a
light-duty truck; and
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4. designed primarily not for use as.-a permanent dwelling but as
temporary living quarters for recreational,camping,travel,orseasonal
use.
"Regulatory floodway" means the channel of a river or other watercourse
and the adjacent land areas that must be reserved in order to discharge the
base flood without cumulatively increasing the watersurface elevation more
than one foot.
"Remedy a violation" means to bring the structure or other development
into compliance with State or local floodplain management regulations, or,
if this is not possible,to reduce the impacts of its noncompliance. Ways that
impacts may be reduced include protecting the.structure or other affected
development from flood damages,implementing the enforcement provisions
of the ordinance or otherwise deterring future similar violations, or reducing
State or Federal financial exposure with regard to the structure or other
development.
"Riverine" means relating to, formed by, or resembling a river (including
tributaries), stream, brook, etc.
"Sheet flow area" -see "Area of shallow flooding".
"Special flood hazard area (SFHA)" means an area in the floodplain
subject to a 1 percent or greater chance of flooding in any given year. It is
shown on an FHBM or FIRM as Zone A, AO, Al A30, AE, A99, or AH.
"Start of construction" includes substantial improvement and other
proposed new development and means the date the building permit was
issued, provided the actual start of construction, repair, reconstruction,
rehabilitation, addition, placement, or other improvement was within 180
days from the date of the permit.. ,The actual start means either the first .
placement of permanent construction of a structure on a site, such as the
pouring of slab or footings, the installation of piles, the construction of
columns, or any work beyond the stage of excavation; or the placement of
a manufacture home on a foundation. Permanent construction does not
include land preparation, such as clearing, grading, and filling; nor does it
include the installation of streets and/or walkways; nor does it include
excavation for a basement, footings, piers, or foundations or the erection of
temporary forms; nor does it include the installation. on the property of
accessory buildings, such.as garages or sheds not occupied as dwelling
units or not part of the main structure. For a substantial improvement, the
actual start of construction means the first alteration of any wall,ceiling,floor,
or other structural part of a building, whether or not that alteration affects the
external dimensions of the building. _
"Structure" means a walled and.roofed building that is principally above
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ground; this includes a gas or liquid storage tank or a manufactured home.
"Substantial damage" means damage of any origin sustained by a
structure whereby the cost of restoring the structure to its before damaged
condition would equal or exceed 50 percent of the market value of the
structure before the damage occurred.
"Substantial improvement" means any reconstruction, rehabilitation,
addition, or other proposed new development of a structure, the cost of
which equals or exceeds 50 percent of the market value of the structure
before the "start of construction" of the improvement. This term includes
structures which have incurred "substantial damage", regardless of the
actual repair work performed. The term does not, however, include either
1. any project for improvement of a structure to correct existing
violations or state or local health, sanitary, or safety code
specifications which have been identified by the local code
enforcement official and which are the minimum necessary to assure
safe living conditions; or
2. any alteration of a "historic structure", provided that the alteration
will not.preclude the structure's continued designation as a "historic
structure".
"Variance" means a grant of relief from the requirements of this ordinance
which permits construction in a manner that would otherwise be prohibited
by this ordinance.
"Violation" means the failure of a structure or other development to be fully
compliant with this ordinance. A structure or other development without the
elevation.certificate, other certifications, or other evidence of compliance
required in this ordinance is presumed-to be in violation until such time as
that documentation is provided.
'Water surface elevation means the height, in relation to the National
Geodetic Vertical Datum (NGVD) of 1929, (or other datum,where specified)
of floods of various magnitudes and frequencies in the floodplains of coastal
or nvenne areas.
"Watercourse" means a lake, river, creek, stream, wash, arroyo, channel
or other topographic feature on or over which waters flow at least
periodically. Watercourse.includes specifically designated areas in which
substantial flood damage may occur.
Sec. 7-5.03 General Provisions
Sec. 7-5.03.1 Lands to Which This Ordinance Applies. This ordinance
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shall-apply to all areas of special flood hazards within the jurisdiction of the'
Town of Los Altos Hills.
Sec.7-6.03.2 Basis for Establishing the Areas of Special Flood Hazard.
The areas of special flood.hazard identified by the Federal Insurance
Administration(FIA)ofthe Federal Emergency ManagementAgency(FEMA)
in the Flood Insurance Study (FIS) for the Town of Los Altos Hills dated
March 30, 1977, and accompanying Flood Insurance Rate Maps (FIRMs),
dated January 2; 1980, and all subsequent amendments and/or revisions,
are hereby adopted by reference and-declared.to be a part of this ordinance.
This FIS and attendant mapping is the minimum area of applicability of this
ordinance and may be supplemented by studies for other areas which allow
implementation of this ordinance and which are recommended to the City
Council by the Floodplain Administrator. The study and FIRMs are on file at
Town Hall, 26379 Fremont Road, Los,Altos Hills, California 94022.
Sec. 7-6.03:3 Compliance. No structure or land shall hereafter be
constructed, located,extended,converted,or altered without full compliance
with the term of this ordinance and other applicable regulations. Violation of
the requirements (including violations of conditions and safeguards
.established.in connection with conditions) shall constitute a misdemeanor.
Nothing herein shall prevent the City Council from taking such lawful action
As is necessary to prevent or remedy any violation.
Sec.7-6.03.4 Abrogation and Greater Restrictions. This ordinance is not
intended to repeal, abrogate, or impair any existing easements,covenants,
or deed restrictions. However,where this ordinance and another ordinance,
easement covenant or deed restriction conflict or overlap, whichever
imposes the more stringent restrictions shall prevail.
Sec. 7-6.03.6 Interpretation. In the interpretation and application of this
ordinance, .all provisions shall be
A. considered as-minimum requirements;
B. liberally construed in favor of the governing body; and
C. deemed neither to limit nor repeal any other powers
granted under state statutes.
Sec. 7-6.03.6 Warning and Disclaimer of Liability. The degree of flood
protection required by this ordinance is considered reasonable for regulatory
purposes and is based on scientific and engineering considerations. Larger
floods can and will occur on rare occasions. Flood heights may be increased
by man-made or natural causes. This ordinance does not imply that land
outside the areas of special flood hazards or uses permitted within such
areas will be free from flooding or flood damages. This ordinance.shall not
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create liability on the part of the Town of Los Altos Hills, any officer or
employee thereof, the State of California, or the Federal .Insurance
Administration, Federal Emergency. Management Agency, for.:any flood
damages that result from reliance on this-ordinance or any administrative
decision lawfully made.hereunder.
Sec. 7-5.03.7 Severability. This ordinance and the various parts thereof
are hereby declared to be severable. Should any section of this ordinance
be declared by the courts to be unconstitutional or invalid, such decision.
shall not affect the validity of the ordinance as a whole, or any portion thereof
other than the section so declared to be unconstitutional or invalid.
Section 7-5.04 Administration
7-6.04.1 Establishment of Development Permit. A development permit
shall be obtained before-any construction or other development begins within
any area of special flood hazard established in Section 7-5.03.2. Application
for a development permit shall be made on forms furnished by the Floodplain
Administrator and may include, but not be limited to: plans in duplicate
drawn to scale showing the nature, location,dimensions,and elevation of the
area in question; existing or proposed structures, fill, storage of materials,
drainage facilities; and the location of the foregoing. Additional application
requirements are described in Titles 9 and 10 of the Los Altos Hills Municipal
Code. Specifically, the following information is required.
A. Site plan, including but not limited to:
1. for all proposed structures,spot ground elevations at
building corners and 20-foot or smaller intervals along
the foundation footprint, or one foot contour elevations
throughout the building site; and
2. proposed locations of water supply, sanitary sewer,
and utilities; and
3. if available, the base flood elevation from the Flood
Insurance Study and/or Flood Insurance Rate Map;and
4. if applicable,the location of the regulatory floodway;
and
B. foundation design detail, including but not limited to:
1. proposed elevation in relation to mean sea level, of
,the lowest floor (including basement) of all structures;
and
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2. for a crawl-space foundation, location and total net
area of foundation openings as required in Section 7-
5.05.1.C.3 of this ordinance and FEMA Technical
Bulletins 1-93 and 7-93; and
3. for foundations placed on fill,the location and height
of fill, and compaction requirements (compacted to 95
percent using the Standard Proctor Test method); and
C. proposed elevation in relation to mean sea level to which
any nonresidential structure will be floodproofed, as required
in'Section 7-5.05.1 C.2 of this ordinance and FEMA Technical
Bulletin TB 3-93; and
D. all appropriate certifications listed in Section 7-5.04.3.D of
this ordinance; and
E. description of the extent to which any watercourse will be
altered or relocated as a result of proposed development.
Sec. 7-5.04.2 Designation of the Floodplain Administrator. The City
Engineer of the Town of Los Altos Hills is hereby appointed to administer,
implement, and enforce this ordinance by granting or denying development
permits in accord with its provisions.
Sec.. 7-5.04.3 Duties and Responsibilities of the Floodplain
Administrator. The duties and responsibilities of the Floodplain
Administrator shall include, but not be limited to the following.
A. Permit Review. Review all development permits to
determine that:
1. permit requirements of this ordinance have been
satisfied,
2. all other required state and federal permits have
been obtained,
3. the site is reasonably safe from flooding, and
4. the proposed development does not adversely affect
the carrying capacity of areas where base flood
elevations have been determined but a floodway has
not been designated. For purposes of this ordinance,
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"adversely affects" means that the cumulative effect of
the proposed development when combined with all
other existing and anticipated development will increase
the water surface elevation of the base flood more than
one foot at any point.
B. Review, Use and Development of Other Base Flood Data.
1. When base flood elevation data has not been
provided in accordance with Section 7-5.03.2, the
Floodplain Administrator shall obtain, review, and
reasonably utilize any base flood elevation and
floodway data available from a federal or state agency,
or other source, in order to administer Section 7-5.05.
Any such information shall be submitted to the Town of
Los Altos Hills for adoption; or
2. If no base flood elevation data is available from a
federal or state agency or other source, then a base
flood elevation shall be obtained using one of two
methods from the FEMA publication "Managing
Floodplain Development in Approximate Zone A Areas
— A Guide for.Obtaining and Developing Base (100-
year) Flood Elevations" dated July 1995 in order to
administer Section 5.
a. Simplified method
i. 100 year or base flood discharge
shall be obtained using the
appropriate regression equation
found in a U.S. Geologicla survey
publication, or the discharge-
drainage area method; and
ii. base flood elevation shall be
obtained using -the Quick-2
computer program developed by
FEMA; -or
b. Detailed method
i. 100 year or base flood discharge :
shall be obtained 'using the U.S.
Army Corps of Engineers'HEC-HMS
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computer program; and
H. base flood elevation shall be
obtained using the U.S. Army Corps
of Engineers' HEC-RAS computer
program.
C. Notification of Other Agencies. In alteration or relocation
of a watercourse:
1. notify adjacent communities and the California.
Department of Water. Resources prior to alteration or
relocation;
2. submit evidence of such notification to the Federal
Insurance Administration, Federal Emergency
Management Agency; and
3. assure that the flood carrying capacity within the
altered or relocated portion of said watercourse is
maintained.
D. Documentation of Floodplain Development. .Obtain and
maintain for public inspection and make available as needed
the following:
1. certification required by Section 7-5.05.1 C.1 and 7-
5.05.4 (lowest floor elevations),
2. , certification required by Section 7-5.05.1 C.2
(elevation orfloodproofing of nonresidential structures),
3. certification required by Sections 7-5.05.1 C.3 (wet
floodproofing standard),
4. certification of elevation required by Section 7-505.3
B (subdivision standards),
5. certification required by Section 7-5.05.6 A(floodway
encroachments),
E. Map Determinations. Make interpretations where needed,
as to the exact location of the boundaries of the areas of
special flood hazard. Where there appears to be a conflict
between a mapped boundary and actual field conditions,grade
-and base flood elevations shall be used to determine the
15 N.WATA1CllentsU.U.AMord0oodplain.on wpd
boundaries of the special flood hazard area. The person
contesting the location of the boundary shall be given a
reasonable opportunityto appeal the interpretation as provided
in Section 7-5.06.
F. Remedial Action. Take action to remedy violations of this
ordinance as specified in Section 7-5.03.3.
Sec. 7-5.04.4 Appeals. The City Council of the Town of Los Altos Hills shall
hear and decide. appeals when - it is alleged there' is an error in any
requirement, decision, or determination made by the Floodplain
Administrator in the enforcement or administration of this ordinance.
Sec. 7-7.05 Provisions for Flood Hazard Reduction
Sec. 7-5.05.1 Standards of Construction. In all areas of special flood
hazards the following standards are required:
A. Anchoring
1. All new construction and substantial improvements
shall be adequately anchored to prevent flotation,
collapse or lateral movement of the structure resulting
from hydrodynamic and hydrostatic loads, including the
effects of buoyancy..
2. All manufactured homes shall meet the anchoring
standards of Section 7-5.05.4.
B. Construction materials and methods. All new construction
and substantial improvement shall be constructed
1. with flood resistant_materials as specified in FEMA
Technical Bulletin TB 2-93, and utility equipment
resistant to flood damage;
2. using. methods and practices that minimize flood
damage;
3. with electrical, heating,ventilation, plumbing and air
conditioning equipment and other service facilities that
are designed and/or located so as to prevent water from
entering or.accumulating within the components during
conditions of flooding; and if
16 N:(DATA\ClientsV-lLAMOrdIFloodplain.ord.wpd
4. within Zones AH or AO, so that there are adequate
drainage paths around structures on slopes to guide
flood waters around and away from proposed
structures.
C. Elevation and floodproofing. (See Section 7-5:02
definitions for "basement," "lowest floor," "new construction,"
"substantial damage" and "substantial improvement".)
1. Residential. construction, new or substantial
_improvement, shall have the lowest floor; including
basement,
a. in an AO zone, elevated above-the highest
adjacent grade to a height equal to or exceeding
the depth number specified in feet on the FIRM,
or elevated at least two feet above the highest
adjacent grade if no depth number is specified.
b. in an A zone, elevated to or above the base
flood elevation; said base flood elevation shall
be determined by one of the methods in Section
7-5.04.3 B of this ordinance.
c. in all other Zones, elevated to or above the-
base flood elevation.
Upon the completion of the structure, the elevation of
the lowest floor including basement shall be certified by
P registered professional engineer or surveyor, .and
verified by the community building inspector to be
properly elevated. Such certification -and verification
shall be provided to the Floodplain Administrator.
2. Nonresidential construction, new or substantial
improvement, shall either be elevated to conform with.
Section 7-5.05:1 C.1 or together with attendant utility
and sanitary facilities
a. be floodproofed below the elevation
recommended under Section 7-5.05.1 CA so
that the structure is watertight with walls
substantially impermeable to the passage of
water;
17 N:IDATAICHerdsU-)LAH10nWoodpLiin.ord.wpd
b. have structural components capable of
resisting hydrostatic and hydrodynamic loads
and effects of-buoyancy; and
c. be certified by a registered professional
engineer that the standards of this section (7-
5.05.1 C.2)are satisfied. Such certification shall
be provided to the Floodplain Administrator.
3. All new construction and substantial improvement
with fully enclosed areas below the lowest floor
(excluding basements)that are usable solely for parking
of vehicles, building access or storage, and which are
subject to flooding, shallbe designed to automatically-
equalize hydrostatic flood forces on exterior walls by
allowing for the entry and exit of floodwater. Designs
for meeting this requirement shall follow the guidelines
in FEMA Technical Bulletins TB 1-93 and TB 7-93, and
must exceed the following minimum criteria:
a. have a minimum of two openings having a
total net area of not less than one square inch.
.for every square foot of enclosed area subject to'
flooding. The bottom of all openings shall be no .
higher than one foot above grade. Openings
may be equipped with screens, louvers, valves
or other coverings or devices-provided that they
permit the automatic_entry and exit of floodwater;
or
b.' be certified by a registered professional-
engineer or architect.
-4. Manufactured homes shall also meet the standards
in Section 7-5.05.4.
Sec. 7-5.05.2 Standards for Utilities.
A. All new and-replacement water supply and sanitary sewage
systems shall be designed to minimize or eliminate:
1. infiltration of flood waters into the systems, and
2. discharge from the systems into flood waters.
18 N:MATA1CIients1LUMXOrdlFloodplain.ord.wpd
B. On-site waste disposal systems shall be located to avoid
impairment to them, or contamination from them during
flooding.
Sec. 7-5.05.3 Standards for Subdivisions.
A. All preliminary subdivision proposals shall identify the
special flood hazard area and the elevation of the base flood.
B. All subdivision plans will provide the elevation of-proposed
-structure(s)and pad(s). If the site is filled above the base flood
elevation, the lowest floor and pad elevations shall be certified
by registered professional engineer or surveyor and provided
to the Floodplain Administrator.
C. All subdivision proposals shall be consistent with the need
to minimize flood damage.
D. All subdivision proposals shall have public utilities'and
facilities such as sewer, gas, electrical and water systems
located and constructed to minimize flood damage.
E. All subdivisions shall provide adequate drainage to reduce
exposure to flood hazards.
Sec. 7-5.05.4 Standards for Manufactured Homes.
A. All manufactured homes that are placed or substantially
improved,within Zones Al-30,AH,andAE on the community's
Flood Insurance Rate Map, on sites located
1. outside of a manufactured home park or subdivision,
2. in a new manufactured home park or subdivision,
3. in an expansion to an existing manufactured home
park or subdivision, or.
4. in an existing manufactured home park or
subdivision on a site upon which a manufactured home .
has incurred "substantial damage" as the result of a
flood,
shall be elevated on a permanent foundation such that-the
lowest floor of the manufactured home is elevated to or above
19 N.MATA%CIierhsV-U AiROrdIRoodpWin.oniwpd
the base flood elevation and be securely fastened to an
adequately anchored foundation system to resist flotation,
collapse, and lateral movement.
B. All manufactured homes to be placed or substantially
improved on sites in an existing-manufactured home park or
subdivision within Zones Al-30, AH, and AE on the
community's Flood Insurance Rate Map that are not subject to
the provisions of paragraph 7-5.05.4 A will be securely
fastened to an adequately anchored foundation system to
resist flotation, collapse, and lateral movement, and be
elevated so that either the
1. lowest floor of the manufactured home is at or above
the base flood elevation, or
2. manufactured home chassis is supported by
reinforced piers or other foundation elements of at least
equivalent strength that are no less than 36 inches in
height above grade.
Upon the completion of the structure, the elevation of the
lowest floor including basement shall be certified by a
registered professional engineer or surveyor, and verified by
the community building inspector to be properly elevated.
Such certification and verification shall be provided to the
Floodplain Administrator.
Sec. 7-5.05.5 Standards for Recreational Vehicles.
A. All recreational vehicles placed on sites within Zones
Al-30, AH, and AE on the community's Flood Insurance Rate
Map will either:
1. be on the site for fewer than 180 consecutive days,
and be fully licensed and ready for highway use — a
recreational vehicle is ready for highway use if it is on
its wheels or jacking system, is attached to the site only
by quick disconnect type utilities and security devices;
and has no permanently attached additions, or
2. meet the permit requirements of Section 7-5.04 of
this ordinance and the elevation and anchoring,
requirements for manufactured homes in Section 7-
5.05.4 A.
20 N.XDATA1CIientslLM AHXOrdlFloodpiain.ord wpd
Sec. 7-5.05.6 Floodways. Located within areas of special flood hazard
established in-Section 7-5.03.2 are areas designated as floodways. Since
the floodway is an extremely hazardous area due-to the velocity of flood
waters, which carry debris, potential projectiles, and erosion potential, the
following provisions apply.
A. Prohibit encroachments, including fill, new construction,
substantial improvement, and other new development unless
certification by a registered professional engineer is provided
demonstrating that encroachments shall—not result in any
increase in [the base]flood elevation during the occurrence of
the base flood discharge.
B. If Section 7-5.05.6 A is satisfied, -ail new construction,
substantial improvement, and other proposed - new
development shall comply with all other applicable flood
hazard reduction provisions of Section 7-5.05.
Sec. 7-5.06 Variance Procedure
Sec. 7-5.06.1 Nature of Variances. The variance criteria set forth in this.
section of the ordinance are based on the general principle of zoning lawthat
variances pertain to a piece of property and are not personal.in nature. A
variance.may be granted-fora parcel of property with physical characteristics
so unusual that complying with the requirements of this ordinance would
create an exceptional hardship to the applicant or the surrounding property
owners. The characteristics must be unique to-the property and not be
shared by adjacent parcels. The unique characteristic must pertain to the
land.itself, not to the structure, its inhabitants, or the property owners.
It is the duty of the Town of Los Altos Hills to help protect its citizens from
flooding. This need is so compelling and the implications of the cost of
insuring a structure built below flood level are.so serious that variances from
the flood elevation or from other requirements in the flood ordinance are
quite rare. The long term goal of preventing and reducing flood loss and
damage can only be met if variances are strictly limited. Therefore,-the
variance guidelines provided in this ordinance are more detailed and contain
multiple provisions that must be met before a variance can be properly"
granted. The criteria are designed to screen out those situations in which
alternatives other than.a variance are more appropriate.
Sec. 7-5.06.2 Appeal.Board.
A. In passing upon requests for variances, the City Council
. 21 N:MATAICiientsb ANIOrd+loodpWn.opd.wpd
_ � •
shall consider -all technical evaluations, all relevant factors,
standards specified in other sections of this ordinance,and the
1. danger.that materials may be swept onto other lands
to the injury of others;
2. danger of life and property due to flooding or erosion
damage;
3. susceptibility of the proposed facility and its contents
to flood damage and the effect of such damage on the
existing individual owner and future owners of the
property;
4. importance of the services provided by the proposed
facility to the community;-
5. necessity to the facility of a waterfront location,
where applicable;
6. availability of alternative locations for the proposed
use which are not subject to flooding or erosion
damage;
7. compatibility of the proposed use with existing and
anticipated development;
8. relationship of the proposed use to the
comprehensive plan and floodplain management
program for that area;
9. safety of access to the property-in time of flood for
ordinary and emergency vehicles;
10. expected heights, velocity, duration, _rate of rise,
and sediment transport of the flood waters expected at-
the site; and
11. costs of providing governmental services during
and after flood"conditions, including maintenance and
repair of public utilities-and facilities such as sewer,gas,
electrical, and water system, and streets and bridges.
B: Any applicant to whom a variance is granted shall be given
written notice-over the signature of a City official that
22 N:IDATAICIfentslLILAHIOrdnoodplafn.ord.wpd
I .
1. the issuance of a variance to construct a.structure
below the base flood level will result in increased
premium rates for flood insurance up to amounts-as
high as $25 for$100 of insurance coverage, and
2. such construction below the base flood level
increases risks to life and-property. It is recommended
that a copy of the notice shall be recorded by the
Floodplain Administrator in the Office of the Santa Clara
County Recorder and shall be recorded in a manner so
that it appears in the chain of title of the affected parcel
of land.
C. The Floodplain Administrator will maintain a record of all,
variance actions, including justification for their issuance, and
report such variances issued in its biennial report submitted to
the Federal Insurance Administration, Federal Emergency
Management Agency.
Sec. 7-5.06.3 Conditions for Variances.
A. Generally, variances may be issued for new-'construction,
substantial improvement, and other proposed new
development to be erected on a lot of one-half acre or less in
size contiguous to and. surrounded by lots with existing
structures constructed below the base flood level, providing
that-the procedures of Sections. 7-5.04 and 7-5.05 of:this
ordinance have been fully considered. - As .the lot size
increases beyond one-half acre, the technical justification
required,for issuing the variance increases.
B. -Variances may be issued for the repair or rehabilitation of
"historic- structures" (as defined in Section 7-5.02 of this
ordinance) upon a determination that the proposed repair or
rehabilitation will not preclude the structure's continued
designation as an historic structure and the variance.is the
minimum necessary' to preserve the historic character and
design of the structure.
C. Variances shall not be issued within any mapped regulatory
floodway if any increase in flood levels during the base flood
discharge would result.
D. Variances shall only be issued upon-a determination that
the variance is the"minimum necessary"considering the flood
23 N:MATA%CllentsU-U AMOrdTloodplWn ord wpd
_ - r
hazard,to afford relief. "Minimum necessary"means to afford
relief with a minimum of deviation from the requirements of this
ordinance. For example, in the case of variances to an
elevation requirement, this means the City Council need not
grant permission for the applicant to build at grade, or even to
whatever elevation the applicant proposes, but only to that
elevation which the City Council believes will both provide relief
and preserve the integrity of the local ordinance.
E. Variances shall only be issued upon a
1. showing of good and sufficient cause-
9 ,
2. determination that failure to grant the variance would
result in exceptional"hardship"(as defined in Section 7-
5.02 of this ordinance) to the applicant; and
3. determination that the granting of a variance will not
result in increased flood heights, additional threats to
public safety, or extraordinary public expense, create a
nuisance (as. defined in Section 7-5.02 - see "Public
safety or nuisance"), cause fraudor victimization-(as
defined in Section 7-5.02 )of the public, or conflict with
existing local laws or ordinances.
F. Variances may be issued for new construction, substantial
improvement, and other proposed new development
necessary for.the conduct of a functionally dependent. use
provided that the provisions of sections 7-5.06.3 A through 7-
5.06.3 E are .satisfied and that the structure or other
development is protected by methods that minimize flood
damages during the base flood and does not result in
additional threats to public safety and does not create a public
nuisance.
G. Upon consideration of the factors of Section 7-5.06.2 A and
the purposes of this ordinance, the City. Council may attach
such conditions to the granting of variances as it deems
necessary to further the purposes of this ordinance.
2. CEQA. This ordinance is .categorically exempt from the California_
Environmental Quality Act (CEQA Guideline Section 15305).
3. SEVERABILITY.- If any part of this ordinance is held to be invalid .or
24 N:IDATA1CIientslLVAH1OrdlFloodplain.ord.wpd
. 4
inapplicable to any situation by a court of competent jurisdiction, such decision shall not
affect the validity of the remaining portions of this ordinance or the applicability of this
ordinance to other situations:
4: EFFECTIVE DATE,• POSTING. This,ordinance shall become effective thirty .
.(30) days from the date of its passage, and shall be posted within the Town of Los Altos
Hills in three (3) public places.
INTRODUCED: September 20.•. 2001.
PASSED: october 18,. 2001.
AYES: Mayor Casey and CouncihTeTbers Cheng, Fenwick, Finn and
O'Malley
NOES:- None
ABSTENTIONS: None
ABSENT: None
By � CGe
CJMayor
ATTEST APPROVED AS TO FORM:
(: n�J
City Clerk City A orney
25 N:iDATAICHen sXLU"Otd+loodptatn.ord wpd