HomeMy WebLinkAbout07/25/2006 Blue Sheet Floodplain Code Revisions
TOWN COUNCIL
MEETING
INFORMATION
TOWN OF MARANA
MEETING DATE: July 25, 2006
AGENDA ITEM:
D.2
TO: MAYOR AND COUNCIL
FROM: Keith Brann, PE, CFM, Assistant Director of Public Works,
Town Engineer
AGENDA TITLE: Presentation: Revisions to the floodplain code, title 21 of the Land
Development Code.
DISCUSSION
The Federal Emergency Management Agency (FEMA) has mandated that all communities that
participate in the National Flood Insurance Program adopt a floodplain management ordinance
with prescribed criteria. Staff has reviewed the Town's current floodplain ordinance, the model
floodplain ordinance supplied by FEMA and various local jurisdictions' ordinances to determine
the best way to revise our current ordinance. Attached is a draft of staff s recommended change
to the Town floodplain ordinance. The draft was crafted primarily from the FEMA model
ordinance, with some modifications to retain key areas of floodplain management currently in
practice in the Town. There are also new areas of floodplain management in this draft version
that staff feels will better protect Marana residents. The current floodplain code, Title 21 of the
Land Development Code, is online at the Town website under Planning Documents.
ATTACHMENTS
Draft Title 21 revision and Floodplain Code Rewrite presentation.
RECOMMENDATION
Staff recommends continued refinement of the ordinance based upon Council comment and
further staff review.
SUGGESTED MOTION
I move that Title 21 of the Land Development Code be further revised per discussion and staff
review, and brought back before Council for adoption.
Floodplain Code Presentation
7/25/20061:33 KEB
TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
TITLE 21
FLOOD PLAIN AND EROSION HAZARD MANAGEMENT CODE
SECTIONS:
21.01
STATUATORY AUTHORIZATION, FINDINGS OF FACT, PURPOSE AND
METHODS
ABBREVIATIONS AND DEFINITIONS
GENERAL PROVISIONS
ADMINISTRATION
PROVISIONS FOR FLOOD-HAZARD REDUCTION
FLOODPLAIN VARIANCE PROCEDURE
21.02
21.03
21.04
21.05
21.06
21.01
GENERAL INFORMATION
21.01.01
STATUTORY AUTHORIZATION
In A.R.S. S 48-3610, the Arizona State Legislature enabled the Town of Marana to adopt regulations in
conformance with A.R.S. S 48-3603 designed to promote the public health, safety and general welfare of
its citizenry. Therefore, the Town Council of the Town of Marana, Arizona, does ordain as follows:
21.01.02
FINDINGS OF FACT
A. The flood hazard areas of the Town of Marana are subject to periodic inundation which may
result in loss of life and property, health and safety hazards, disruption of commerce and
governmental services, extraordinary public expenditures for flood protection and relief and
impairment of the tax base, all of which adversely affect the public health, safety and general
welfare.
B. Flood losses may be exacerbated by the cumulative effects of obstructions to flow, inadequate
anchoring of structures and encroachment into the floodplain. Uses that are inadequately flood
proofed, elevated or otherwise protected from flood damage, also contribute to the flood loss.
21.01.03
STATEMENT OF PURPOSE
It is 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:
A. To protect human life and health;
B. To minimize expenditure of public money for costly flood control projects;
C. To minimize the need for rescue and relief efforts associated with flooding and generally
undertaken at the expense of the general public;
D. To minimize prolonged business interruptions;
E. To minimize damage to public facilities and utilities such as water and gas mains,
electric, telephone and sewer lines, streets and bridges located in areas of special flood
hazard;
F. To help maintain a stable tax base by providing for the sound use and development of
areas of special flood hazard so as to minimize blight areas caused by flooding;
G. To insure that potential buyers are notified that property is in an area of special flood
hazard;
H. To insure that those who occupy the areas of special flood hazard assume responsibility
for their actions; and
I. To maintain eligibility for disaster relief.
Title 21 - Flood Plain & Erosion Hazard Management Code
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TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
21.01.04 METHODS OF REDUCING FLOOD LOSSES
In order to accomplish its purposes, this ordinance includes methods and provisions for:
A. Restricting or prohibiting uses which are dangerous to health, safety and property due to
water or erosion hazards, or which result in damaging increases in erosion or in flood
heights or velocities;
B. Requiring that uses vulnerable to floods, including facilities which serve such uses, be
protected against flood damage at the time of initial construction;
C. Controlling the alteration of natural floodplains, stream channels and natural protective
barriers, which help accommodate or channel flood waters;
D. Controlling filling, grading, dredging and other development which may increase flood
damage; and
E. Preventing or regulating the construction of flood barriers that will unnaturally divert flood
waters or which may increase flood hazards in other areas.
Title 21 - Flood Plain & Erosion Hazard Management Code
Page 2 of 28
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TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
21.02
ABBREVIATIONS AND DEFINITIONS
21.02.01
ABBREVIATIONS
The following common abbreviations are used throughout this Ordinance:
ADWR
BFE
CFS
CLOMR
EHS{L)
FEMA
FFE
FIA
FIRM
LOMR
NGVD
NAVD
SFHA
21.02.02
Arizona Department of Water Resources
Base Flood Elevation
Cubic Feet per Second
Conditional Letter of Map Revision
Erosion Hazard Setback or Erosion Hazard Setback limit
Federal Emergency Management Agency
Finished Floor Elevation
Federal Insurance Administration
Flood Insurance Rate Map
Letter of Map Revision
National Geodetic Vertical Datum (of 1929)
North American Vertical Datum (of 1988)
Special Flood Hazard Area
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.
AII-Weather-Access. Access considered traversable by normal passenger vehicles, defined as a
permanent, durable material with adequate protection against scour and erosion and having a depth of
water no more than 12 inches above the roadway surface during a base flood.
Appeal. A request for a review of the Floodplain Administrator's interpretation of any provision of this
ordinance or a request for a floodplain variance.
Area of Shallow Flooding. A designated AO or AH Zone on a community's FIRM with a one percent or
greater annual chance of flooding to an average depth of one to three feet where a clearly defined
channel does not exist, where the path of flooding is unpredictable or where velocity flow may be evident.
Such flooding is characterized by ponding or sheet flow.
Base Flood. The flood having a one percent chance of being equaled or exceeded in any given year.
Base Flood Elevation (BFE). The Water Surface Elevation associated with the Base Flood.
Basement. Any area of a building having its floor sub-grade (below ground level) on all sides.
Building. See "Structure".
Conditions and Restrictions. Standard requirements which are placed on a parcel of land, the
development permit applicant and the parcel owner by the Floodplain Administrator as a condition of the
applicant's or owner's use of the floodplain.
Community. Any state, area or political subdivision thereof, or any Indian tribe or authorized tribal
organization, or authorized native organization, which has authority to adopt and enforce floodplain
management regulations for the areas within its jurisdiction.
Revised XXXX
Title 21 - Flood Plain & Erosion Hazard Management Code
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Marana 7/26/06 Draft
TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
Critical facilities. Facilities that are considered critical in their need to remain serviceable during a major
flood event or that their inundation by flood waters poses a high risk to the health, safety or welfare of the
community.
Detention. A drainage system which delays the downstream progress of flood waters in a controlled
manner, generally through the combined use of a temporary storage area and a metered outlet device
which causes a lengthening of the duration of flow and thereby reduces downstream flood peaks.
Developer. Any person, group or entity proposing or constructing a development as defined by this
Ordinance.
Development. 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,
and storage of materials and equipment located within the area of special flood hazard.
Encroachment. 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.
Erosion. The process of the gradual or avulsive wearing away of landmasses due to the flow of water.
Erosion Hazard Setback. A prescribed horizontal distance measured from the primary channel bank of
an incised channel or from the design storm's water surface limits for a non-incised channel for the
purpose of providing a measure of safety against lateral erosion.
Existing Manufactured Home Park or Subdivision. 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, construction of streets and either final site
grading or the pouring of concrete slabs) is completed before the effective date of the floodplain
management regulations adopted by the community.
Expansion to an Existing Manufactured Home Park or Subdivision. 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).
Five Hundred Year Flood. The flood having a 0.2% chance of being equaled or exceeded in any given
year.
Flood or Flooding. A general and temporary condition of partial or complete inundation of normally dry
land areas from: (1) the overflow of flood waters; (2) the unusual and rapid accumulation or runoff of
surface waters from any source; and/or (3) the collapse or subsidence of land along the shore of a lake or
other body of water as a result of erosion or undermining caused by waves or currents of water exceeding
anticipated cyclical levels or suddenly caused by an unusually high water level in a natural body of water,
accompanied by a severe storm or by an unanticipated force of nature, such as flash flood or an
abnormal tidal surge, or by some similarly unusual and unforeseeable event which results in flooding as
defined in this definition.
Flood Boundary and Floodway Map (FBFM). The official map on which FEMA or FIA has delineated
the areas of special flood hazards and the floodway.
Flood Hazard Boundary Map (FHBM). The official map on which FEMA or FIA has delineated the areas
of flood hazards.
Flood Insurance Rate Map (FIRM). The official map on which FEMA or FIA has delineated both the
special flood hazard areas and the risk premium zones applicable to the community.
Title 21 - Flood Plain & Erosion Hazard Management Code
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TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
Flood Insurance Study (FIS). The official report provided by FIA that includes flood profiles, FIRM,
FBFM and the water surface elevation of the base flood.
Flood Zones (FEMA defined):
. Zone X.
. Zone X-500
. Zone AE Floodway
Area free from a base flood
Area free from a base flood due to a manmade protective structure
or an area with base flood elevations or sheet flow elevations less
than one foot. Area is also known as Shaded Zone X.
SFHA with no Base Flood Elevations determined.
SFHA with Base Flood Elevations determined by the Flood
Insurance Studyfor Pima County.
SFHA with flood depths of 1 to 3 feet (usually areas of ponding);
Base flood Elevations determined by the Flood Insurance Study for
Pima County.
SFHA with flood Depths of 1 to 3 feet (usually sheet flow on sloping
terrain); average depths determined. For areas of alluvial fan
flooding, velocities also determined. The Flood maps show the
depth in 1 foot increments and velocities in 1 foot per second
increments.
That portion of a regulated watercourse's SFHA which must remain
clear of any development. See also definition for Floodway.
. Zone A.
. Zone AE
. Zone AH
. Zone AO
Floodplain or Flood-Prone Area. Any land area susceptible to being inundated by water from any
source. For regulatory purposes this involves either a FEMA Special Flood Hazard Area, areas platted
on accepted Town of Marana plans as being flood prone or locally regulated areas that may be inundated
by water during a base flood.
Floodplain Administrator. The individual appointed to administer and enforce the floodplain
management regulations. Unless otherwise stated, the Town Engineer is the Floodplain Administrator.
Floodplain Board. The Town Council of The Town of Marana, at such times as they are engaged in the
enforcement of this ordinance.
Floodplain Management. The operation of an overall program of corrective and preventive measures
for reducing flood damage, including but not limited to emergency preparedness plans, flood control
works and floodplain management regulations.
Floodproofing. Any combination of structural and non-structural 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 by means other than elevating.
Flood-Related Erosion. The collapse or subsidence of land along the shore of a lake or other body of
water as a result of undermining caused by waves or currents of water exceeding anticipated cyclical
levels or suddenly caused by an unusually high water level in a natural body of water, accompanied by a
severe storm, or by an unanticipated force of nature, such as a flash flood or an abnormal tidal surge, or
by some similarly unusual and unforeseeable event which results in flooding.
Floodway. 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 a designated height. Also referred to as "Regulatory Floodway."
Floodway Fringe. That area of the floodplain on either side of the "Regulatory Floodway" where
encroachment may occur.
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Functionally Dependent Use. A use which cannot perform its intended purpose unless it is located or
carried out in close proximity to water. The term includes only docking or port facilities that are necessary
for the loading and unloading of cargo or passengers, and ship building and ship repair facilities, but does
not include long-term storage or related manufacturing facilities.
Governing Body. The Town of Marana, which is empowered to adopt and implement regulations to
provide for the public health, safety and general welfare of its citizenry.
Hardship. Related to Section 21.06, "Floodplain variances", of this ordinance means the exceotional
hardship which would result from a failure to grant the requested floodplain variance. The governing body
requires that the floodplain 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 or the 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 floodplain 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. The highest natural elevation of the ground surface prior to construction
adjacent to the proposed walls of a structure.
Historic Structure. Any structure that is:
A. 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
(Secretary) as meeting the requirements for individual listing on the National Register;
B. Certified or preliminarily determined by the Secretary 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;
C. Individually listed on a state inventory of historic places in states with historic preservation
programs which have been approved by the Secretary; or
D. Individually listed on a local inventory of historic places in communities with historic
preservation programs that have been certified either:
a. by an approved state program as determined by the Secretary; or
b. directly by the Secretary in states without approved programs.
Levee. A man-made structure designed and constructed in accordance with sound engineering practices
to contain, control or divert the flow of water so as to provide protection from temporary flooding.
Locally Regulated Floodplain. Floodplains in the Town of Marana associated with washes and/or sheet
flow areas having a 100-year peak discharge of 50 cfs or more.
Lowest Floor. The lowest floor of the lowest enclosed area, includinq basement (see "Basement"
definition). An unfinished or flood resistant enclosure, usable solely for parking of vehicles, building
access or storage in an area other than a basement area is not considered a building's lowest floor,
provided that such enclosure is not built so as to render the structure in violation of the applicable non-
elevation design requirements of this ordinance.
Manufactured Home. 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. A parcel (or contiguous parcels) of land divided into two or
more manufactured home lots for sale or rent.
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TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
Market Value. Market Value is determined by estimating the cost to replace the structure in new
condition and adjusting that cost figure by the amount of depreciation that 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 in a report prepared by an independent professional
appraiser and supported by a written explanation of the differences.
Mean Sea level. For purposes of the National Flood Insurance Program, the National Geodetic Vertical
Datum (NGVD) of 1929 or North American Vertical Datum (NAVD) of 1988, to which base flood
elevations shown on a community's FIRM are referenced.
New Construction. For the purposes of determining insurance rates, structures for which the "start of
construction" commenced on or after the effective date of an initial FIRM or after December 31, 1974,
whichever is later, and includes any subsequent improvements to such structures. For floodplain
management purposes, "new construction" means structures for which the "start of construction"
commenced on or after the effective date of a floodplain management regulation adopted by a community
and includes any subsequent improvements to such structures.
New Manufactured Home Park or Subdivision. 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 the 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. A common name for the flood having a one percent chance of being equaled
or exceeded in any given year. (See "Base Flood" definition)
Person. An individual or his agent, firm, partnership, association or corporation, or agent of the
aforementioned groups, or this state or its agencies or political subdivisions.
Recreational Vehicle. A vehicle that is:
A. Built on a single chassis;
B. 400 square feet or less when measured at the largest horizontal projection;
C. Designed to be self-propelled or permanently towable by a light duty truck;
D. Designed primarily not for use as a permanent dwelling but as temporary living quarters
for recreational, camping, travel or seasonal use.
Regulatory Flood Elevation. An elevation one foot above the base flood elevation for a watercourse for
which the base flood elevation has been determined and shall be determined by the criteria developed by
the Director of ADWR for all other watercourses.
Regulatory Floodplain. An area associated with a watercourse, including its channel, or any other
floodplain or floodprone area that would be inundated by the base flood, including all base floods where
the 1 OO-year peack discharge is 50 cfs or greater.
Title 21 - Flood Plain & Erosion Hazard Management Code
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TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
Regulatory Floodway. See definition for f1oodway.
Repetitive Loss Structure. A structure covered by a contract for flood insurance issued pursuant to the
NFIA that has incurred flood-related damage on two occasions during any 10-year period ending on the
date of the event for which a second claim is made, in which the cost of repairing the flood damage, on
average, equaled or exceeded 25 percent of the market value of the structure at the time of each such
flood event. In addition to the current claim, the NFIP must have paid the previous qualifying claim.
Retention. A drainage system which stops the downstream progress of flood waters by employing
methods of containment and storage and uses infiltration, evaporation or re-use to dispose of stored
waters, thereby eliminating basin contributions to the downstream flood peaks or volumes.
Sheet Flow Area. (See "Area of Shallow Flooding')
Special Flood Hazard Area (SFHA). An area defined by FEMA within a community subject to a one
percent or greater chance of flooding in any give year (base flood). These areas are designated as Zone
A, AO, AH and AE on the Flood Insurance Rate Map and other areas determined by the criteria adopted
by the Director of ADWR.
Start of Construction. Includes substantial improvement, 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 of the permit date. 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 manufactured 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. A walled and roofed building, including a gas or liquid storage tank, which is principally above
ground, as well as a manufactured home. "Structure" for insurance coverage purposes, means a walled
and roofed building, other than a gas or liquid storage tank, that is principally above ground and affixed to
a permanent site, as well as a manufactured home on a permanent foundation. For the latter purpose,
the term includes a building while in the course of construction, alteration or repair, but does not include
building materials or supplies intended for use in such a construction, alteration or repair, unless such
materials or supplies are within an enclosed building on the premises.
Substantial Damage. 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 damage also means flood-related damage sustained
by a structure on two separate occasions during a rolling 10-year period for which the cost of repairs at
the time of each such flood event, on the average, equals or exceeds 25 percent of the market value of
the structure before the damage occurred.
Substantial Improvement. Any reconstruction, rehabilitation, addition or other improvement 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:
A. Any project for improvement of a structure to correct existing violations of state or local
health, sanitary or safety code specifications which have been identified by the local code
Title 21 - Flood Plain & Erosion Hazard Management Code
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enforcement official and which are the minimum necessary to assure safe living
conditions; or,
B. Any alteration of a "historic structure", provided that the alteration would not preclude the
structure's continued designation as a "historic structure".
Variance, Floodplain. A grant of relief from the requirements of this ordinance that permits construction
in a manner that would otherwise be prohibited by this ordinance.
Violation. The failure of a structure or other development to be fully compliant with the community's
floodplain management regulations. 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. The height, in relation to the National Geodetic Vertical Datum (NGVD) of
1929 or North American Vertical Datum (NA VD) of 1988 of floods of various magnitudes and frequencies
in the floodplains of riverine and ponding areas. See also Base Flood Elevation.
Watercourse. 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 (e.g. the regulatory floodplain).
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SECTION 21.03 GENERAL PROVISIONS
21.03.01 LANDS TO WHICH THIS ORDINANCE APPLIES
This ordinance shall apply to the following lands within the corporate limits of the Town of Marana:
A. All special flood hazard areas as defined by FEMA
B. FEMA zone X-500, also known as shaded zone X, as it pertains to alluvial fan or sheet flooding
C. Local floodplains associated with washes and/or sheet flow having a 100-year peak discharge of
50 cfs or more
D. Areas within the erosion hazard setback of a watercourse
E. All floodplains/flood-prone areas and erosion hazard setbacks identified on previously and
subsequently recorded subdivision plats
F. All floodplains/flood-prone areas and erosion hazard setbacks identified on previously and
subsequently drainage studies commissioned by the Town Engineer
21.03.02
BASIS FOR ESTABLISHING THE AREAS OF SPECIAL FLOOD HAZARD
The regulated areas of this ordinance as outlined in section 21.03.01 are derived from a variety of
sources, whose hydrologic and hydraulic data and maps of delineation are kept on file by the Town of
Marana at 11555 West Civic Center Drive, Marana, AZ 85653, Marana Municipal Complex, Public Works
Department. This information includes or will include:
A. The area of special flood hazard identified by the Federal Insurance Administration (FIA) of the
Federal Emergency Management Agency (FEMA) in a scientific and engineering report entitled
"The Flood Insurance Study (FIS) for Pima County Arizona and incorporated areas, revised
February 8,1999," with accompanying Flood Insurance Rate Maps (FIRMs), dated February 8,
1999 and all subsequent amendments and/or revisions, are hereby adopted by reference and
declared to be a part of this ordinance. The FIS, FIRMs FBFM and amendments and corrections
to the maps are all kept on file.
B. The FIS and FIRMs may be supplemented by studies for other areas that allow implementation of
this ordinance. The Floodplain Board, within the limits of the Town of Marana, shall require
developers of land to delineate, within areas where development is ongoing or imminent,
floodplains consistent with the criteria developed by FEMA, the Director of Water Resources and
the Town.
C. Due to the episodic nature of natural flood events and the resulting changes to hydrologic and
hydraulic conditions along watercourses within the Town, base flood peak discharges, flow
volumes, and associated regulatory floodplain and erosion hazard areas are subject to
continuous revision. At a minimum, base flood values and base flood elevations will meet or
exceed the current values established by FEMA and reflect historic flood information and general,
current watershed conditions. Current regulatory floodplain and erosion hazard area maps will
be maintained by the Floodplain Administrator for the Santa Cruz River and all watersheds which
generate regulatory flood peak discharges exceeding 5,000 cfs for the base flood. These
watersheds are listed in Appendix 1 of this ordinance.
D. The Floodplain Administrator may accept hydrologic and hydraulic studies prepared by an
Arizona Registered Professional Civil Engineer as a delineation of regulatory floodplain and
erosion hazard setback areas.
E. In all cases the most recently accepted information shall be used for floodplain management.
21.03.03
COMPLIANCE
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LAND DEVELOPMENT CODE
All development of land, construction of residential, commercial or industrial structures, or future
development on lands to which this ordinance applies is subject to the terms of this ordinance and other
applicable regulations.
21.03.04
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.
21.03.05
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.
21.03.06
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 special flood hazard areas or uses permitted within such areas will be free
from flooding or flood damages. This ordinance shall not create liability on the part of The Town of
Marana, any officer or employee thereof, the State of Arizona, NFIA or FEMA, for any flood damages that
result from reliance on this ordinance or any administrative decision lawfully made hereunder.
21.03.07
STATUTORY EXEMPTIONS
A In accordance with AR.S. 9 48-3609(H), unless expressly provided, this and any regulation
adopted pursuant to this article do not affect:
1. Existing legal uses of property or the right to continuation of such legal use. However, if a
nonconforming use of land or a building or structure is discontinued for twelve months, or
destroyed to the extent of 50 percent of its value as determined by a competent appraiser, any
further use shall comply with this article and regulations of the Town of Marana
2. Reasonable repair or alteration of property for the purposes for which the property was legally
used on July 9, 1974, or any regulations affecting such property takes effect, except that any
alteration, addition or repair to a nonconforming building or structure which would result in
increasing its flood damage potential by 50 percent or more shall be either flood proofed or
elevated to or above the regulatory flood elevation;
3. Reasonable repair of structures constructed with the written authorization required by AR.S. 9
48-3613; and
4. Facilities constructed or installed pursuant to a Certificate of Environmental Compatibility
issued pursuant to AR.S. Title 40, Chapter 2, Article 6.2.
B. Before any authorized construction begins for the exceptions listed below, the responsible person
must submit plans for the construction to the Floodplain Board for review and comment. In
accordance with AR.S. 948-3613, written authorization shall not be required, nor shall the
Floodplain Board prohibit:
1. The construction of bridges, culverts, dikes and other structures necessary to the construction of
public highways, roads and streets intersecting or crossing a watercourse;
2. The construction of storage dams for watering livestock or wildlife, structures on banks of a
watercourse to prevent erosion of or damage to adjoining land if the structure will not divert,
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retard or obstruct the natural channel of the watercourse or dams for the conservation of
floodwaters as permitted by AR.S. Title 45, Chapter 6;
3. Construction of tailing dams and waste disposal areas for use in connection with mining and
metallurgical operations. This paragraph does not exempt those sand and gravel operations that
will divert, retard or obstruct the flow of waters in any watercourse from complying with and
acquiring authorization from the Floodplain Board pursuant to regulations adopted by the
Floodplain Board under this article;
4. Other construction upon determination by the Floodplain Board that written authorization is
unnecessary;
5. Any flood control district, county, city, town or other political subdivision from exercising powers
granted to it under AR.S. Title 48, Chapter 21, Article 1;
6. The construction of streams, waterways, lakes and other auxiliary facilities in conjunction with
development of public parks and recreation facilities by a public agency or political subdivision;
and
7. The construction and erection of poles, towers, foundations, support structures, guy wires and
other facilities related to power transmission as constructed by any utility whether a public service
corporation or a political subdivision.
C. In addition to other penalties or remedies otherwise provided by law, this state, a political
subdivision or a person who may be damaged or has been damaged as a result of the unauthorized
diversion, retardation or obstruction of a watercourse has the right to commence, maintain and
prosecute any appropriate action or pursue any remedy to enjoin, abate or otherwise prevent any
person from violating or continuing to violate this section or regulations adopted pursuant to this
Article. If a person is found to be in violation of this Section, the court shall require the violator to
either comply with this Section if authorized by the Floodplain Board or remove the obstruction and
restore the watercourse to its original state. The court may also award such monetary damages as
are appropriate to the injured parties resulting from the violation including reasonable costs and
attorney fees.
21.03.08
UNLAWFUL ACTS
A It is unlawful for a person to engage in any development or to divert, retard or obstruct the flow of
waters in a watercourse if it creates a hazard to life or property without securing the written
authorization required by AR.S. S 48-3613. Where the watercourse is a delineated floodplain, it
is unlawful to engage in any development affecting the flow of waters without securing written
authorization required by AR.S. S 48-3613.
B. Any person violating the provisions of this Ordinance shall be guilty of a class 2 misdemeanor.
Each day that a violation continues shall be considered a separate offense.
21.03.09
DECLARATION OF PUBLIC NUISANCE
Every new structure, building, fill, excavation or development located or maintained within any special
flood hazard area after August 8, 1973, in violation of this ordinance, and without written authorization
from the Floodplain Board, is a public nuisance per se and may be abated, prevented or restrained by
action of the Town of Marana.
21.03.10
ABATEMENT OF VIOLATIONS
Within 30 days of discovery of a violation of this ordinance, the Floodplain Administrator shall submit a
report to the Floodplain Board which shall include all information available to the Floodplain Administrator
which is pertinent to said violation. Within 30 days of receipt of this report, the Floodplain Board shall
either:
A Take any necessary action to effect the abatement of such violation; or
B. Issue a floodplain variance to this ordinance in accordance with the provisions of Section 21.06
herein; or
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c. Order the owner of the property upon which the violation exists to provide whatever additional
information may be required for their determination. Such information must be provided to the
Floodplain Administrator within 30 days of such order and the Floodplain Administrator shall
submit an amended report to the Floodplain Board within 20 days. At the next regularly
scheduled public meeting, the Floodplain Board shall either order the abatement of said violation
or they shall grant a floodplain variance in accordance with the provisions of Section 21.06
herein; or
D. For FEMA regulated special flood hazard areas, submit to the administrator of NFIA a declaration
for denial of insurance, stating that the property is in violation of a cited state or local law,
regulation or ordinance, pursuant to Section 1316 of the NFIA of 1968 as amended.
E. The Town of Marana may withhold the issuance of permits, including building permits, native
plant permits and grading permits, for the development or improvement on the parcel or a any
contiguous parcel of land under the same ownership.
21.03.11 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.
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SECTION 21.04
ADMINISTRATION
21.04.01 DESIGNATION OF THE FLOODPLAIN ADMINISTRATOR
The Town Engineer or his/her designee is hereby appointed to administer, implement and enforce this
ordinance by granting or denying floodplain use permits in accordance with its provisions. Duties of the
Floodplain Administrator shall include, but not be limited to:
A. Review all development permits to determine that:
1. The 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;
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, "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 tenth of a foot at any point located off of the
property which is to be occupied by the anticipated development.
B. Use of Other Base Flood Data. When base flood elevation data has not been provided in
accordance with Section 21.03.02, the Floodplain Administrator shall obtain, review and
reasonably utilize any base flood elevation data available from a federal, state or other source, in
order to administer Section 21.05. Any such information shall be consistent with the
requirements of FEMA and the Director of Water Resources and shall be submitted to the
Floodplain Board for adoption.
C. Obtain and maintain for public inspection and make available the following:
1. The certified regulatory flood elevation required in Section 21.05.01.C.1;
2. The Zone AO certification required in Section 21.05.01.C.2;
3. The f1oodproofing certification required in Section 21.05.01.C.5;
4. The certified opening elevation required in Section 21.05.01.C.6; and
D. Whenever a watercourse is to be altered or relocated:
1. Notify adjacent communities and ADWR prior to such alteration or relocation of a
watercourse, and submit evidence of such notification to FIA through appropriate
notification means; and
2. Require that the flood carrying capacity of the altered or relocated portion of said
watercourse be maintained.
E. Advise the Pima County Flood Control District (PCFCD) and any appropriate jurisdiction having
responsibility for floodplain management in writing and provide a copy of a development plan of
all applications for floodplain use permits or floodplain variances to develop land in a floodplain or
f100dway within one mile of the corporate limits of the Town of Marana. Also, advise the PCFCD
in writing and provide a copy of any development plan of any major development proposed within
a floodplain or floodway, which could affect floodplains, f100dways or watercourses within the
district's area of jurisdiction. Written notice and a copy of the plan of development shall be sent to
the district no later than three (3) working days after having received a complete application by
the Town of Marana.
F. Make interpretations, where needed, as to the exact location of the boundaries of the areas of
special flood hazards (e.g., where there appears to be a conflict between a mapped boundary
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and actual field conditions). The person contesting the location of the boundary shall be given a
reasonable opportunity to appeal the interpretation as provided in Section 21.06.
G. Take actions on violations of this ordinance as required in Section 21.03.10 herein.
H. Notify FEMA and ADWR of acquisition by means of annexation, incorporation or otherwise, of
additional areas of jurisdiction.
I. Within one hundred twenty (120) days after completion of construction of any flood control
protective works which changes the rate of flow during the flood or the configuration of the
floodplain upstream or downstream from or adjacent to the project, the person or agency
responsible for installation of the project shall provide to the governing bodies of all jurisdictions
affected by the project a new delineation of all floodplains affected by the project. The new
delineation shall be done according to the criteria adopted by the Director of Water Resources.
J. A community's base flood elevations may increase or decrease resulting from physical changes
affecting flooding conditions. As soon as practicable, but not later than six months after the date
such information becomes available, a community shall notify the Administrator (FEMA) of the
changes by submitting technical or scientific data in accordance with this part. Such a
submission is necessary so that upon confirmation of those physical changes affecting flooding
conditions, risk premium rates and flood plain management requirements will be based upon
current data.
21.04.02
ESTABLISHMENT OF FLOODPLAIN USE PERMIT
A. A Floodplain Use Permit shall be obtained before construction or development begins, including
placement of manufactured homes, upon any land to which this ordinance applies as defined in
section 21.03.01.
B. Application for a Floodplain Use Permit shall be made on forms furnished by the Floodplain
Administrator and include, but not be limited to:
a. plans in duplicate drawn to scale showing the nature, location, dimensions and elevation
of the area in question with contour lines at minimum 1 foot intervals
b. datum used for plan and structures with conversion factor between NGVD and NA VD
c. existing or proposed structures
d. fill
e. storage of materials
f. drainage facilities
g. Proposed elevation in relation to specified datum of the lowest floor (including basement)
of all structures. In Zone AO, elevation of existing highest adjacent natural grade and
proposed elevation of lowest floor of all structures
h. Proposed elevation in relation to mean sea level to which any non-residential structure
will be flood-proofed
i. Certification by an Arizona Registered Professional Civil Engineer or architect that the
flood proofing methods for any nonresidential structure meet the flood proofing criteria in
Section 21.05.01.C.5
j. Require base flood elevation data for all subdivisions
k. Information requested by the Floodplain Administrator as found on the site plan checklist
used for the purpose of floodplain management
I. Description of the extent to which any watercourse will be altered or relocated as a result
of proposed development
m. Items required or permitted as part of State Standard SS6-05 (Development of Single
Family Homes in Floodplain).
C. Permit applications shall be reviewed to determine whether the proposed site alterations and
improvements will be reasonably safe from flooding and lateral erosion and will not otherwise
aggravate existing conditions. If a proposed development is found to be in the path of flooding,
lateral erosion or would aggravate existing conditions, improvements shall be relocated or
adequate protective measures shall be taken to avoid aggravating the existing conditions.
D. Floodplain use permits shall be subject to a fee in accordance with the adopted Town of Marana
Fee Ordinance Schedule.
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E. Conditions and Restrictions shall apply to all floodplain use permits as administered by the
Floodplain Administrator.
F. No permit shall be issued for any development which is not in conformance with this ordinance or
any other provision of law relating to such development. A floodplain use permit may be denied if
the proposed development constitutes a danger or hazard to life or property. In making such a
determination, the Floodplain Administrator may consider the following factors, which are not all-
inclusive:
a. The danger to life, person, or property due to increased flood heights, velocities, or
redirection of flow cause by the development;
b. The danger that materials may be swept onto other lands or downstream to the injury of
others;
c. The proposed water supply or sanitation systems of any development and the ability of
these systems to prevent disease, contamination and unsanitary conditions if they should
become flooded or eroded;
d. The susceptibility of the proposed development and/or its contents to flood damage and
the effect of such damage on the individual owners;
e. The availability of alternative locations for the proposed use on the same property which
are in areas not subject to flooding or erosion;
f. The compatibility of the proposed use with existing regulatory floodplain uses and with
floodplain management programs anticipated in the foreseeable future;
g. The relationship of the proposed use to any comprehensive plan and floodplain
management program for the area;
h. All weather access to the property;
i. The expected heights, velocity, duration, rate of rise, and sediment transport of the flood
waters expected at the site under both existing and proposed conditions;
j. Documentation that all necessary permits have been obtained from state and federal
agencies; and
k. Such other factors which are relevant to the purposes of this Ordinance.
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SECTION 21.05
PROVISIONS FOR FLOOD HAZARD REDUCTION
The following subsections of 21.05 contain the standards of construction for lands to which this ordinance
applies per section 21.03.01 and are further restricted or supplemented by the requirements that follow. In
all cases, impact to adjacent, upstream or downstream properties shall be taken into account.
A. The water surface elevation may not be increased by more than one tenth of a foot at any point
located off of the property which is to be occupied by the anticipated development.
B. The velocity of the watercourse may not be increased by ten percent or by more than 1.0 foot per
second, whichever is less.
21.05.01
STANDARDS OF CONSTRUCTION IN FLOODPRONE AREAS
A. Anchoring
1. All new construction and substantial improvements shall be 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 21.05.05.A.2.
B. Construction Materials and Methods
1. All new construction and substantial improvements shall be constructed with materials
and utility equipment resistant to flood damage;
2. All new construction and substantial improvements shall be constructed using methods
and practices that minimize flood damage;
3. All new construction, substantial improvement and other proposed new development
shall be constructed 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;
4. Within FEMA Zones AH or AO, adequate drainage paths around structures on slopes are
required to guide floodwaters around and away from proposed structures;
5. Structures designed or utilized for human habitation, whether full or part time, shall only
be permitted where the product of the flow depth d, in feet, times the square of the flow
velocity v, in feet per second, of the surrounding floodwaters of the base flood does not
exceed the numerical value of eighteen (dv2:;; 18) for a period greater than 30 minutes in
duration as determined by an Arizona Registered Professional Civil Engineer and
accepted by the Floodplain Administrator and the surrounding floodwaters of the base
flood do not exceed three feet in depth; and
6. All Structures designed or utilized for human habitation or commercial enterprise,
whether full or part time, located within a floodplain or erosion hazard setback area shall
provide protection for scour and lateral erosion based upon a scour/erosion analysis
sealed by an Arizona Registered Professional Civil Engineer and accepted by the
Floodplain Administrator. In all cases scour protection shall be designed to be a
minimum three feet below the lowest point of the adjacent channel or thalweg.
C. Elevation and Flood-proofing
1. New construction and substantial improvement of any residential structure shall have the
lowest floor, including basement, elevated at or above the regulatory flood elevation;
2. New construction and substantial improvement of any residential structure in Zone AO shall
have the lowest floor, including basement, elevated at least one foot higher than the depth
number on the FIRM, measured from the highest existing adjacent grade;
3. New construction and substantial improvement of any residential structure in Zone A with no
base flood elevations shall have the lowest floor, including basement, elevated at least four
feet higher than the highest existing adjacent grade unless an engineering analysis is
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performed by an Arizona Registered Professional Civil Engineer to determine the base flood
elevations, at which the requirement will then be a minimum of one foot above the base flood
elevation.
4. New construction and substantial improvement of any residential structure in Zone X-500
shall have the lowest floor, including basement, elevated at least eighteen inches (18") higher
than the highest existing adjacent grade.
5. Non-residential construction shall either be elevated in conformance with the preceding
requirements or together with attendant utility and sanitary facilities:
a. be flood-proofed so that below the regulatory flood level the structure is watertight with
walls substantially Impermeable to the passage of water;
b. have structural components capable of resisting hydrostatic and hydrodynamic loads and
effects of buoyancy; and
c. be certified by an Arizona Registered Professional Civil Engineer or architect that the
standards of this subsection are satisfied. Such certifications shall be provided to the
Floodplain Administrator.
6. All new construction and substantial improvements with fully enclosed areas below the lowest
floor that are useable solely for parking of vehicles, building access or storage in an area
other than a basement and which are subject to flooding shall be designed to automatically
equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of
floodwaters. Designs for meeting this requirement must either be certified by an Arizona
Registered Professional Civil Engineer or architect to meet or exceed the following minimum
criteria:
a. a minimum of two openings on different sides of each enclosed area that have a total
net area of not less than one square inch for every square foot of enclosed area subject
to flooding shall be provided;
b. the bottom of all openings shall be no higher than one foot above grade; and
c. openings may be equipped with screens, louvers, valves or other coverings or devices
provided that they permit the automatic entry and exit of floodwaters.
7. Manufactured homes shall meet the above applicable standards and also the standards in
Section 21.05.05.
8. If fill is used to elevate any structure, the fill shall extend at such elevation for a distance of at
least fifteen feet beyond the outside limit of the structure unless a study/analysis prepared by
an Arizona Registered Professional Civil Engineer demonstrates that a lesser distance is
acceptable.
9. Upon the completion of the structure and prior to the issuance of a certificate of occupancy
the elevation of the lowest floor including basement shall be certified by an Arizona
Registered Professional Civil Engineer or surveyor and provided to the Floodplain
Ad m inistrator.
21.05.02 STANDARDS FOR STORAGE OF MATERIALS AND EQUIPMENT
A. The storage or processing of materials that are, in time of flooding, buoyant, flammable, explosive
or could be injurious to human, animal or plant life is prohibited.
B. Storage of other material or equipment may be allowed if not subject to major damage by floods
and if firmly anchored to prevent flotation, or if readily removable from the area within the time
available after flood warning.
C. Storage of materials and equipment is further restricted in the Floodway per section 21.05.09.
21.05.03
STANDARDS FOR UTILITIES
A. All new or replacement water supply and sanitary sewage systems shall be designed to minimize
or eliminate infiltration of flood waters into the system and discharge from systems into flood
waters.
B. On-site waste disposal systems shall not be located in a regulatory floodplain or erosion hazard
setback area if a more suitable area exists on the parcel.
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C. Waste disposal systems shall not be installed wholly or partially in a regulatory floodway.
Crossings are allowed if buried at least one foot below the calculated scour depth as determined
in a study/analysis prepared by an Arizona Registered Professional Civil Engineer.
D. Utilities shall be buried at least one foot below the calculated scour depth as determined in a
study/analysis prepared by an Arizona Registered Professional Civil Engineer.
21.05.04
STANDARDS FOR SUBDIVISIONS AND COMMERCIAL DEVELOPMENTS
A. All preliminary subdivision plats and development plans shall delineate the FEMA SFHA,
Floodway if applicable, locally regulated floodplain, erosion hazard setback areas, and base flood
elevations. The pre and post development condition is to be shown.
B. All final subdivision plats shall provide the elevation(s) of proposed structure(s) and pads affected
by or adjacent to flood hazards. If the site is filled above the base flood, the final lowest floor and
pad elevation shall be certified by an Arizona Registered Professional Civil Engineer or surveyor
and provided to the Floodplain Administrator. All final subdivision plats shall delineate the FEMA
SFHA, Floodway if applicable, locally regulated floodplain and erosion hazard setbacks in a
surveyable manner and sealed by an Arizona Registered Land Surveyor.
C. All improvement plans relating to grading, paving, sewer or drainage shall delineate the FEMA
SFHA, locally regulated floodplain, erosion hazard setback areas and base flood elevations. The
pre and post development conditions are to be shown.
D. All subdivision and commercial development proposals shall be consistent with the need to
minimize flood damage.
E. All subdivision and commercial development proposals shall have public utilities and facilities
such as sewer, gas, electrical and water systems located and constructed to minimize flood
damage.
F. All subdivisions and commercial developments shall provide adequate drainage to reduce
exposure to flood hazards.
G. All subdivisions with a minimum lot size of 16,000 square feet or less shall be platted such that
FEMA SFHA, locally regulated floodplains, and erosion hazard setback areas are not located on
individual lots. Such areas are to be contained within common areas.
H. All subdivisions with a minimum lot size greater than 16,000 square feet shall show buildable pad
areas for each lot in which a FEMA SFHA, locally regulated floodplain or erosion hazard setback
appears on said lot. Pad elevations, encroachments, and/or erosion hazard setback protective
measures are to be designed by an Arizona Registered Professional Civil Engineer as part of the
project.
I. When a modification or removal of a FEMA SFHA is to be pursued by a development, the
following requirements apply:
1. A hydraulic analysis and engineering plans for the modifications must be accepted by the
Floodplain Administrator. New delineations of the floodplain conditions shall be prepared
in conformance with the requirements of FEMA for LOMRs, the state Director of Water
Resources, and the Town.
2. A CLOMR must be submitted to and accepted by FEMA prior to the recording of a final
plat for subdivisions.
3. A CLOMR must be submitted to and accepted by FEMA prior to construction of physical
improvements.
4. Subdivision lots to be affected by a LOMR will not be partially released from assurance
agreements or have certificate of occupancies granted until the LOMR has become
effective.
5. Commercial/Industrial buildings to be affected by a LOMR will not be granted a certificate
of occupancy, including temporary certificate of occupancy, until the LOMR has become
effective unless the building as constructed meets the requirements of this ordinance for
the pre-LOMR conditions.
J. All subdivisions and commercial/industrial developments shall provide all weather access in
accordance with section 21.05.12.
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21.05.05
STANDARDS FOR MANUFACTURED HOMES AND MANUFACTURED HOME
PARKS OR SUBDIVISIONS
Manufactured homes and manufactured home parks or subdivisions must meet other applicable
requirements of section 21.05 that have not been supplemented or revised by this
subsection.
A. All manufactured homes and substantially improved manufactured homes located within lands to
which this ordinance applies per section 21.03.01 shall be required to comply with the following:
1. Be elevated so that the bottom of the structural frame or the lowest point of any attached
appliances, whichever is lower, is at or above the regulatory flood elevation; and
2. Be securely anchored to resist flotation, collapse or lateral movement by one of the
following methods:
a. Provision of an anchoring system designed to withstand horizontal forces of 25
pounds per square foot and uplift forces of 15 pounds per square foot; or
b. Provision of over-the-top and frame ties to ground anchors, specifically:
1. Over-the-top ties be provided at each of the four corners of the manufactured
home, with two additional ties per side at intermediate locations, except that
manufactured homes less than fifty (50) feet long require only one (1) additional
tie per side; and
2. Frame ties be provided at each corner of the home with five (5) additional ties per
side at intermediate points, except that manufactured homes less than fifty (50)
feet long require only four (4) additional ties per side; and
3. All components of the anchoring system be capable of carrying a force of 4,800
pounds.
B. All manufactured home parks or subdivisions located within lands to which this ordinance applies
per section 21.03.01 shall be required to comply with the following:
1. All manufactured homes shall be placed on pads or lots elevated on compacted fill so
that the bottom of the structural frame and any attached electrical appliances is at or
above the regulatory flood elevation; or
2. Shall be placed on stem walls or pilings so that the bottom of the structural frame and
any attached electrical appliances is at or above the regulatory flood elevation.
a. Lots shall be large enough to permit steps.
b. Pilings or stem wall shall be placed in stable soil.
c. Pilings shall be no more than ten (10) feet apart.
C. Certification that the installation of a manufactured home meets all of the requirements of this
section is required. Such certification shall be provided by the person installing the manufactured home,
the owner, the developer of a manufactured home park or subdivision, or an agency regulating
manufactured home placement, whichever is deemed appropriate by the Floodplain Administrator.
Certification of Finished Floor Elevation shall be in accordance with section 21.05.01.C.9.
21.05.06 STANDARDS FOR RECREATIONAL VEHICLES
All recreational vehicles placed on site will either:
A. Be on 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
B. Meet the permit requirements of Section 21.04.02 of this ordinance and the elevation and anchoring
requirements for manufactured homes in Section 21.05.05.
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21.05.07 STANDARDS FOR CRITICAL FACILITIES
Critical facilities are to be managed for floodplain to the SOO-year event. Critical facilities shall be
required to abide by the following requirements:
A. Structures or facilities that produce, use or store more than 100,000 gallons of highly volatile,
flammable, explosive, toxic and/or water-reactive materials shall be located outside of the 500-
year FEMA floodplain (shaded Zone X) and locally regulated floodplain calculated at the 500 year
interval.
B. Public and private utility facilities that are vital to maintaining or restoring normal services to
flooded areas before, during and after a flood are to be located outside of the FEMA Special Flood
Hazard Area and locally regulated floodplain. Such facilities are to be designed to avoid or
function normally during a SOO-year flood.
C. Police stations, fire stations, hospitals, nursing homes, assisted living homes, public vehicle and
equipment storage facilities, emergency operations centers and schools designated to be used as
temporary shelters are to be located outside the FEMA Special Flood Hazard Area and locally
regulated floodplain. Such facilities are to be designed to avoid or function normally during a 500-
year flood.
D. The developers of critical facilities that remain in the SOO-year floodplain shall certify the safety of
the development by providing the following information to the satisfaction of the Floodplain
Adm inistrator:
a. Freeboard requirements shall be such that the finished floor elevation shall be elevated
one foot above the SOO-year water surface elevation.
b. Developer shall delineate any five hundred year floodplains and the respective erosion
hazard setback areas within 200 feet of the parcel or development.
c. Five hundred year water surface elevations shall be delineated by the developer on the
preliminary/final plats, development plans and improvement plans.
d. Toe downs and bank protection shall be designed to withstand the SOO-year flood.
21.05.08 STANDARDS FOR EXCAVATIONS, INCLUDING SAND AND GRAVEL OPERATIONS
Excavations, including Sand and Gravel Operations may be permitted provided the following
minimum conditions are met. Additional conditions apply for operations occurring within a regulatory
floodwayas required in section 21.05.09.
A. Extraction of sand, gravel and other materials is allowed provided that excavations are not so
located nor of such depth, or width, or length or combination of depth-width-Iength as to present a
hazard to structures (including but not limited to roads, bridges, culverts, and utilities), to the
banks of watercourses, to other property, or which adversely affects groundwater recharge.
B. There shall be no stockpiling within special flood hazard areas of materials or tailings that may
obstruct, divert, or retard the flow of floodwaters except as reviewed and accepted by the
Floodplain Administrator on an individual floodplain use permit basis.
C. Due to the rapidly changing hydraulic characteristics of watercourses in the Town of Marana, and
the effects excavations have on these characteristics, floodplain use permits for excavations shall
only be issued for a limited time period not to exceed one (1) year, subject to annual renewal and
review by the Floodplain Administrator. Renewals will only be granted after receipt and
acceptance of a report by the operator showing that the sand and gravel excavations remain in
compliance with the conditions of the previous floodplain use permit, current floodplain conditions
and all current related floodplain management regulations.
D. In addition to those conditions provided for elsewhere, floodplain use permits for excavations may
impose site specific conditions based upon hydraulics and sediment transport regarding the area
and location in which excavations are allowed, the maximum amount of material to be excavated,
and other reasonable restraints on the methods of operating in relationship to the floodplain
conditions.
E. Any extraction of sand and gravel or related materials in lands to which this ordinance applies as
specified in section 21.03.01 will only be allowed if a reclamation plan is also provided for the
extraction operation. The reclamation plan shall show in sufficient detail the actions which are
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TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
proposed to reclaim the excavated areas so that all adverse effects of extraction are mitigated.
The plan shall also contain a timetable and financial assurances for accomplishing reclamation.
F. The Floodplain Administrator may require bonds or other financial assurances appropriate for the
sand and gravel extraction operation.
G. The Floodplain Administrator may require hydrologic, hydraulic and geomorphic analyses
addressing the existing conditions as well as the impacts under the proposed method of
operation.
21.05.09
FLOODWAY REQUIREMENTS
Located within special flood hazard areas established in Section 21.03.02 are areas designated as
floodways. Since the f100dway is an extremely hazardous area due to the velocity of floodwaters which
carry debris, potential projectiles and erosion potential, encroachments are prohibited, including fill, new
construction, substantial improvements and other development. The following subsections clarify how the
f100dway can be developed:
A. The following open space uses shall be permitted within the f100dway to the extent that they are
not prohibited by any provision of this Ordinance or any other ordinance, law or regulation, and
provided they do not require fill, excavation, or the storage of materials or equipment:
a. Agricultural uses, including general farming, pasture, grazing, outdoor plant nurseries,
horticulture, viticulture, truck farming, sod farming, and wild crop harvesting
b. Industrial-commercial uses such as loading areas, airport landing strips, and parking
areas
c. Private and public recreational uses, including golf courses, tennis courts, driving ranges,
archery ranges, picnic grounds, boat launch ramps, swimming areas, parks, wildlife and
nature preserves, game farms, fish hatcheries, shooting preserves, target ranges, trap
and skeet ranges, hunting and fishing areas, hiking and horseback riding trails
d. Accessory residential uses, including lawn gardens, parking areas and play areas
B. Excavations, including Sand and Gravel Operations may occur in the floodway under the
following conditions in addition to those required in section 21.05.08:
a. There shall be no stockpiling of materials or tailings within the floodway.
b. Excavations may be allowed only in those reaches of watercourses which have, at a
minimum, a balanced sediment system, Le., the sediment coming into the reach is equal
to or greater than the sediment leaving the reach and the long term sediment balance for
the entire river system indicates that the stream channel will aggrade.
C. Flood Control structures designed to protect life or property from the dangers or hazards of
floodwaters are permitted provided all other provisions of this Ordinance are met.
D. No use shall be allowed which:
a. Acting alone or in combination with existing or future uses creates danger or hazard to
life or property. In determining whether a use creates a danger or hazard to property, the
Floodplain Administrator may require a certification by an Arizona Registered
Professional Civil Engineer that the proposed use will not result in any increase in the
floodway elevations during the occurrence of the base flood nor will the proposed use
divert, retard or obstruct the flow of flood waters.
b. Increases the regulatory floodway elevation
c. Adversely effects groundwater recharge
d. Increases erosion potential upstream and/or downstream
e. Places a waste disposal system wholly or partially in a floodway
21.05.10
EROSION HAZARD SETBACK REQUIREMENTS
Close proximity to watercourses poses a hazard to development due to lateral erosion. Per section
21.03.01, the erosion hazard setback area of a watercourse is a land covered by this ordinance.
A. Along natural watercourses where unusual conditions exist, the erosion hazard setback shall be
established on a case-by-case basis by the Floodplain Administrator, unless an engineering study
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LAND DEVELOPMENT CODE
is done to establish the limits by an Arizona Registered Professional Civil Engineer and accepted
by the Floodplain Administrator.
B. Along incised natural watercourses where no unusual conditions exist, a standard setback
measured from the top of the primary channel bank shall be provided at the time of development.
The setback may be reduced by an engineering analysis performed by an Arizona Registered
Professional Civil Engineer and accepted by the Floodplain Administrator in accordance with
subsection 21.05.10.0.
C. Along non-incised natural watercourses (Le. sheet flow areas) where no unusual conditions exist,
a standard setback measured from the base flood limits shall be provided at the time of
development. The setback may be reduced by an engineering analysis performed by an Arizona
Registered Professional Civil Engineer and accepted by the Floodplain Administrator in
accordance with subsection 21.05.10.0.
D. Standard erosion hazard setbacks may be reduced by an engineering study performed by an
Arizona Registered Professional Civil Engineer and accepted by the Floodplain Administrator.
The reduced setbacks shall not fall below minimum allowable erosion hazard setbacks unless the
study also includes an analysis performed by an Arizona Registered Professional Geological
Engineer. The following table shows the standard and minimum allowable setbacks when no
physical construction is made to prevent erosion hazard:
Base flood flow rate in cubic feet Standard Erosion Hazard Minimum allowable Erosion
per second (cfs) Setback (feet) Hazard Setback (feet)
<500 25 15
500-1999 50 20
2000-4999 75 35
5000-9999 100 60
10,000 and greater 250 175
Santa Cruz 500 350
21.05.11
A.
DETENTION AND RETENTION REQUIREMENTS
Any development with a residential density of 3 or more units per acre, or any residential
development larger than 1 acre that has a density of 6 units per developed acre, as well as all
proposed commercial and industrial developments shall provide some method of peak and/or
volumetric runoff reduction. The amount of reduction is stipulated in the Pima County Storm
Water Detention/Retention manual. The peak runoff reduction should be provided through
detention of storm water and storm water harvesting for irrigation where possible.
B. Balanced and critical drainage basins are watersheds that have been identified by the chief
Engineer of the Pima County Flood Control District as unsuitable for increased development
because of the high probability of increased flooding with development and the potential for
flooding of existing improvements or property. Critical and balanced basins may be
developed further only upon the incorporation of adequate detention systems or flood control
facilities, as reviewed and accepted by the Floodplain Administrator. Drainage basins that
have not previously been identified as unsuitable for additional urban development shall be
considered balanced basins, but upon study by the Floodplain Administrator, may be
classified as critical basins. These detention systems or flood control facilities shall be
incorporated into any and all future basin-development proposals, regardless of size or land-
use density.
C. Structural flood control measures may be proposed in conjunction with, or in place of
detention/retention systems if it can be clearly demonstrated that such measures will not alter
the water and sediment equilibrium of the affected watercourse, and will mitigate
environmental impacts. Structural flood control measures, such as channelization to a logical
conclusion downstream of the proposed development and/or improvements to existing offsite
flood control systems within the applicable drainage or stream reach, shall be completed in
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accordance with plans reviewed and accepted by the Floodplain Administrator.
D. Localized areas lacking sufficient improved or natural receiving waters into which runoff may
be discharged can be required to follow alternative drainage solutions including complete
retention practices as directed by the Town Engineer.
E. A fee may be collected by the Town in lieu of detention/retention system when it can be
clearly demonstrated that the detention at the site does not provide offsite flood relief due to
the parcel size, location within the drainage basin, or other factors. The fees collected will be
used to construct public flood control improvements that will mitigate the potential damage of
flood waters originating from the property contributing the fees. In balanced and critical
drainage basins, and where development is less than 3 units per acre, use of a fee system
will be encouraged in lieu of a detention system in order to preserve the natural drainage
patterns. The fee shall be equivalent to the cost of a detention system that would otherwise
be constructed for the development to mitigate increased storm water runoff created by the
proposed development.
F. The Floodplain Administrator shall maintain a map of critical and balanced basins within the
jurisdictional limits of the Town of Marana.
21.05.12
ACCESS REQUIREMENTS
A. Development shall provide all weather access in accordance with the following requirements:
1 . Developments that fall under the requirements of subdivisions of ten or fewer lots of the
Land Development Code are required to provide all weather access from each lot to the
subdivision entrance. All weather access from the subdivision entrance to the nearest
paved public right of way may be waived if the following criteria is met:
a. Subdivision is characterized as a residential subdivision
b. Subdivision is of a rural character, i.e. has minimum lot sizes of 36,000 square
feet
c. If, in the determination of the Floodplain Administrator, it is not possible or
feasible to construct such access to the subdivision entrance
d. Section 21.05.12.B provisions are be utilized.
2. All subdivisions that do not fall under the preceding requirements shall provide all
weather access from each lot to a paved public right of way. A subdivision with more
than one access to a paved public roadway need only have one all weather access.
3. All commercial developments shall provide all weather access from a paved public
roadway to all public portions of their site. Nonpublic portions of a commercial
development that are not all weather access shall be gated and signs posted in
accordance with section 21.05.12.B provisions.
4. Private residential construction not part of a recorded subdivision is required to construct
an all weather access from the property boundary to a paved public roadway. If in the
determination of the Floodplain Administrator it is not possible to construct such access
to the property, then section 21.05.12.B provisions may be utilized.
B. The Floodplain Administrator may allow certain exemptions to all weather access as stated in
preceding section. A condition of allowing this exemption is that the owner shall execute and
record a covenant running with the land enforceable by the Town of Marana, Pima County
and the Pima County Flood Control District which contains the following:
1. An acknowledgement that the vehicular access may be impassable to conventional motor
vehicles and emergency vehicles in times of flooding,
2. A hold harmless provision, holding the Town of Marana, its agents, the Floodplain
Management Board, Pima County and the Pima County Flood Control District harmless
from and against all injuries and damages resulting from the traversing or attempting to
traverse the vehicle access during times of flooding, and
3. The covenant, successors and assigns shall erect and maintain a sign(s) in a location(s)
and size(s) acceptable to the Town of Marana stating "DO NOT ENTER WHEN
FLOODED"
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TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
SECTION 21.06 FLOODPLAIN VARIANCE PROCEDURE
21.06.01 NATURE OF FLOODPLAIN VARIANCES
The floodplain variance criteria set forth in this section of the ordinance are based on the general
principle of zoning law that floodplain variances pertain to a piece of property and are not personal in
nature. A floodplain variance may be granted for a 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 Marana to help protect its citizens from flooding. This need is so
compelling and the implications of the cost of insuring a structure built below the regulatory flood
elevation is so serious that floodplain 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 floodplain variances are strictly limited. Therefore, the floodplain variance
guidelines provided in this ordinance are more detailed and contain multiple provisions that must be
met before a floodplain variance can be properly granted. The criteria are designed to screen out
those situations in which alternatives other than a floodplain variance are more appropriate.
21.06.02 APPEAL BOARD
A. The Floodplain Board of The Town of Marana shall hear and decide appeals and requests for
floodplain variances from the requirements of this ordinance.
B. The Floodplain Board 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.
C. In passing upon such applications, the Floodplain Board shall consider all technical evaluations,
all relevant factors, standards specified in other sections of this ordinance, and:
1. the danger that materials may be swept onto other lands to the injury of others;
2. the danger of life and property due to flooding or erosion damage;
3. the susceptibility of the proposed facility and its contents to flood damage and the effect of
such damage on the individual owner;
4. the importance of the services provided by the proposed facility to the community.
5. The necessity to the facility of a waterfront location, where applicable;
6. the availability of alternative locations for the proposed use, which are not subject to flooding
or erosion damage;
7. the compatibility of the proposed use with existing and anticipated development;
8. the relationship of the proposed use to the comprehensive plan and floodplain management
program for that area;
9. the safety of access to the property and all of its habitable structures in time of flood for
ordinary and emergency vehicles;
10. the expected heights, velocity, duration, rate of rise, and sediment transport of the flood
waters expected at the site; and,
11. the costs of providing governmental services during and after flood conditions, including
maintenance and repair of public utilities and facilities such as sewer, gas, electrical, water
system and streets and bridges.
D. Upon consideration of the factors of Section 21.06.02.C and the purposes of this ordinance, the
Floodplain Board may attach such conditions to the granting of floodplain variances as it deems
necessary to further the purposes of this ordinance.
E. Any applicant to whom a floodplain variance is granted shall be given written notice over the
signature of a community official that:
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LAND DEVELOPMENT CODE
1. the issuance of a floodplain 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.
3. The land upon which the floodplain variance is granted shall be ineligible for
exchange of state land pursuant to the flood relocation and land exchange
program provided for by A.R.S. title 26, chapter 2, article 2. A copy of the notice
shall be recorded in the office of the Pima County recorder and shall be recorded
in a manner so that it appears in the chain of title of the affected parcel of land.
F. The Floodplain Administrator shall maintain a record of all floodplain variance actions, including
justification for their issuance and report such floodplain variances issued in its biennial report
submitted to the FEMA.
21.06.01.1 CONDITIONS FOR FLOODPLAIN VARIANCES
A. Generally, floodplain variances may be issued for new construction and substantial improvements
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 the procedures of Sections
21.04 and 21.05 of this ordinance have been fully considered. As the lot size increases beyond
one-half acre, the technical justification required for issuing the floodplain variance increases.
B. Floodplain variances may be issued for the repair, rehabilitation, restoration, or flood proofing of
structures listed in the National Register of Historic Places or the State Inventory of Historic
Places, upon a determination that the proposed repair or rehabilitation will not preclude the
structure's continued designation as a historic structure and the floodplain variance is the
minimum necessary to preserve the historic character and design of the structure.
C. Floodplain variances may be issued.for accessory structures used solely for limited storage that
have a size of less than 150 square feet, provided that the following requirements are met:
1. Structure is anchored to resist flotation, collapse and lateral movement;
2. The portions of the structure located below the BFE are constructed of flood resistant
materials;
3. The structure is designed to allow for the automatic entry and exit of flood waters;
4. Any mechanical, utility or electrical equipment is elevated or flood proofed above the BFE;
and
5. The structure does not violate any floodway requirements.
D. Floodplain variances may be issued for agricultural structures whose use is exclusively in
connection with the production, harvesting, storage, drying, or raising of agricultural commodities,
including the raising of livestock, such as pole and pre-fabricated metal structures, grain bins and
corn cribs provided that the following requirements are met:
1. The structure is designed in a manner that results in minimal damage from flooding;
2. The contents stored in the structure will create no additional threat to the public;
3. The structure is designed to allow for the automatic entry and exit of flood waters;
4. Any mechanical, utility or electrical equipment is elevated or flood proofed above the
BFE; and
5. The structure does not violate any floodway requirements.
E. Floodplain variances shall not be issued within any designated floodway if any increase in flood
levels during the base flood discharge would result.
F. Floodplain variances shall only be issued upon a determination that the floodplain variance is the
minimum necessary, considering the flood hazard, to afford relief.
G. Floodplain variances shall only be issued upon:
1. a showing of good and sufficient cause;
2. a determination that failure to grant the floodplain variance would result in exceptional
hardship to the applicant;
3. a showing that the use cannot perform its intended purpose unless it is located or carried
out in close proximity to water. This includes only facilities defined in Section 21.02.02 of
this ordinance in the definition of "Functionally Dependent Use"; and,
Title 21 - Flood Plain & Erosion Hazard Management Code
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TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
4. a determination that the granting of a floodplain variance will not result in increased flood
heights, additional threats to public safety, extraordinary public expense, create
nuisances, cause fraud on or victimization of the public or conflict with existing local laws
or ordinances.
Title 21 - Flood Plain & Erosion Hazard Management Code
Page 27 of 28
Revised XXXX
Marana 7/26/06 Draft
TOWN OF MARANA, ARIZONA
LAND DEVELOPMENT CODE
APPENDIX 1- TABLE OF REGULATORY PEAK DISCHARGES
Note: List is not all inclusive; remaining watersheds area also subjected to Marana Floodplain and
Erosion Hazard Management Code restrictions. Listed discharges are subject to review
and revision due to urbanization and improvements. Check with the Town Engineer
before their use.
Blanco Wash @ Los Robles Wash
Brawley Wash @ Los Robles Wash
Hardy Wash @ Camino De Oeste Road
Little Brawley Wash @ 32d7'25"
111d19'45"
Los Robles Wash @ Blanco Wash
Picture Rock Wash @ Picture Rocks Road
Santa Cruz River @ Cortaro Road
Tortolita Fan
Canada Agua Canyon @ 1-10 5,255
Cochie Canyon @ 1-10 5,779
. Cottonwood Canyon @ 1-10 5,439
Derrio Canyon @ 1-10 5,229
Eastern Limit of Fan @ 1-10 4,084
Guild Canyon @ 1-10 4,561
Ruelas Canyon @ 1-10 4,604
Prospect Canyon @ 1-10 4,340
Wild Burro @ 1-10 5,831
REGULATORY
17,000
35,000
4,536
13,440
DESIGN
22,000
40,000
37,000
3,4 79
70,000
42,000
80,000
Unless otherwise noted, design discharges shall be 20 percent greater than regulatory
discharges.
Title 21 - Flood Plain & Erosion Hazard Management Code
Page 28 of 28
Revised XXXX
Marana 7/26/06 Draft
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