2020 COMPREHENSIVE PLAN FINAL DRAFT 2-1-2021.PDF

Flood Control District of Maricopa County
Comprehensive Report
& Program 2020
Maricopa County, Arizona

Flood Control District of Maricopa County
Comprehensive Report & Program
Board of Directors of the Flood Control District
Jack Sellers, Chairman
Jack Sellers, District 1
Steve Chucri, District 2
Bill Gates, District 3
Clint Hickman, District 4
Steve Gallardo, District 5
Flood Control Advisory Board
Richard Schaner, Chairman
Vacant, Vice Chair
Richard Schaner, Member, District 1
Vacant, Member, District 2
Hemant Patel, Member, District 3
DeWayne Justice, Member, District 4
Vacant, Member, District 5
Kyle Tilghman, Salt River Project, Ex Officio Member
Ray Dovalina, City of Phoenix, Ex Officio Member
County Manager
Joy Rich
Director, Flood Control District
Michael Fulton
Adopted on XXXXX, 2021

Comprehensive Report and Program - 2020
Comprehensive Report
and Program – 2020
Introduction
In response to a series of devastating floods and increasing rapid urbanization in high flood hazard areas, State of
Arizona lawmakers saw a need for regional flood management, enacting legislation for the creation of flood
control districts in 1959. The Flood Control District of Maricopa County (District) was initially organized under
Title 5, Chapter 10, Article 4, §45-2351 to §45-2371 Arizona Revised Statutes in August 3, 1959. This statute was
repealed in 1985 and replaced by Title 48, Chapter 21, Article 1, Arizona Revised Statutes (ARS).
Upon formation of the District, a survey of flood control problems and a report of existing flood control facilities
were required. This initial report was completed in 1963. ARS §48-3616 states, “the report shall be prepared at
least every five years beginning in 1985 and shall indicate the past efforts of the district in eliminating or minimizing
flood control problems and state the planned future work of the district to eliminate or minimize flood control
problems.” The Comprehensive Report and Program (Report) must be approved by both the Flood Control
1

Comprehensive Report and Program - 2020
Advisory Board (FCAB) and the Flood Control District Board of Directors (BOD). Subsequent Reports were
prepared and approved in 1989, 1991, 1997, 2002, 2005, 2009, and 2015.
As required by A.R.S. §48-3616 A and B, this report addresses the following:
 A survey of the flood control problems of the district,
 A description of existing flood control facilities in the area,
 Recommendations as to cooperation between the district and the owner or owners of existing facilities,
 Recommendations and a preliminary plan for the construction or other acquisition of facilities to carry
out the purpose of the district, and a description of the property proposed to be acquired or damaged in
performing the work,
 A program for carrying out the regulatory functions,
 A map showing the district boundaries and location of the work proposed to be done and property taken
or damaged,
 An estimate of the cost of the proposed work and such other things as the board of directors may
request.
A separate document required by state statute is prepared and submitted to the BOD for a five-year Capital
Improvement Program (CIP). The CIP drives design and construction of new infrastructure in conjunction with the
District's planning activities. The CIP establishes a schedule and funding for each capital improvement project
according to its priority, merit, and need. Additionally, the CIP documents how planned projects will help the
larger community by aligning District planning with other local agency planning efforts.
The Report provides a broader assessment of issues and long-range strategies, and is submitted to the BOD to
tentatively adopt and schedule a public hearing on the program and performance of work. This 2020 update to
the 2015 Comprehensive Report and Program captures the key elements required by state statute.
2

Comprehensive Report and Program - 2020
Survey of Flood Control Problems
In order to understand and identify flood control problems for Maricopa County, knowledge of the physical
environment and the effects of development are needed. A brief review of the geographic scope, storms and
flooding, benefits of floodplains, and socioeconomic and development issues will help give an overall picture of
the challenges and flood control problems that remain.
Geographic Scope
Jurisdiction
The District is a political taxing subdivision of the State of Arizona with the powers, privileges and immunities
granted generally to municipal corporations. The District’s jurisdictional boundary includes all unincorporated
and incorporated areas within the boundary limits of Maricopa County. All property owners within the county
pay a property tax to the District.
Size and Topography
The county has a land area of 9,226 square miles, of which 2,190 square miles are incorporated (23.7 percent) and
7,036 square miles are unincorporated (76.3 percent). Twenty-five cities and towns are located within Maricopa
County. The county has a larger land area than eight states and the District of Columbia. It is the fifth largest of
Arizona’s 15 counties, and the 14th largest county in the United States. The county measures 132 miles from east
to west and 103 miles from north to south. The land surface elevation ranges between 436 and 7,657 feet above
sea level.
Geology
Maricopa County lies within the Basin and Range province
of the southwestern U.S., which includes the southern
third of Arizona. The Maricopa County portion of the
Basin and Range province is located within the Sonoran
Desert and is characterized by wide valleys and mountain
ranges. The mountain systems are generally comprised of
metamorphic and igneous rocks that have slow infiltration
rates, which can cause rapid runoff. Volcanics are more
dominant in the northern and western portions, while
basalts are more common in the west. The majority of
the populated areas of Maricopa County are located
along the alluvial deposits of the river basins, which can
be erosive.
Water table depth, location of aquifers, and subsidence issues due to excessive ground water withdrawals can
affect or contribute to flooding in some areas and may negatively impact flood control structures. The Arizona
Department of Water Resources (ADWR) is responsible for regulation of groundwater.
Hydrologic Soil Groups
A Hydrologic Soil Group is a group of soils that have similar runoff potential under similar storm and vegetative
cover conditions. These groupings are used in calculations that estimate runoff from rainfall. These physical
properties of soil influence runoff potential, or the minimum rate of infiltration for a bare soil after prolonged
wetting and when not frozen. The soils in Maricopa County are placed into four Hydrologic Soil Groups; A, B, C,
and D as defined by the Natural Resources Conservation Service (NRCS). Hydrologic Soil Groups A and B have low
3

Comprehensive Report and Program - 2020
and moderate runoff potential. Soils in these two groups range from sands and/or gravels to sandy loams and
clay loams. Most of the county can be characterized as Hydrologic Soil Groups A or B. Hydrologic Soil Groups C
and D have a high runoff potential. These soils are primarily silt and clays or have an impervious under layer, such
as bedrock that impedes the downward movement of water. Approximately 35 percent of Maricopa County,
excluding the Tonto National Forest and the Barry M. Goldwater Gunnery Range, fall into Hydrologic Group C or
D. These groups are in the mountains and low hills of the county.
Hydrology
Six major watercourses flow through Maricopa
County: Centennial Wash, and the Agua Fria,
Gila, Hassayampa, Salt, and Verde Rivers. These
rivers drain an area of approximately 57,000
square miles, including areas of New Mexico
and Mexico. The Agua Fria, Hassayampa, and
Verde Rivers flow from north to south. The Salt
River flows east to southwest and bisects
Maricopa County. The Gila River, which flows
from the southwest, joins the Salt River near the
center of the county and continues in a
southwesterly direction toward the county line.
Additionally, approximately 11,000 miles of
rivers, streams, and washes flow through
Maricopa County. Few rivers have perennial
flow, and some of the perennial flow is treated
wastewater, agricultural tail water, or other
urban runoff. The majority of washes are
ephemeral and only have flow during storms.
Some of these may remain dry for several years
before a storm will result in sufficient runoff to
create flows.
Geomorphology
In the desert, both natural and artificial processes can shape landforms, as well as create relatively sudden (in
geologic time) changes. Whether unexpected or predictable, these geologic changes can affect the drainage
patterns of an area. The majority of the urbanized populations live in the valleys and along the floodplains of the
major washes and their tributaries where the results of processes such as sedimentation and erosion culminate,
and thus they are more likely to be susceptible to flooding.
Desert landforms, such as arroyos and alluvial fans, are an example of erosion forces and depositional processes
that are characteristic of the desert. Arroyos and alluvial fans can both influence and be influenced by
floodwaters.
Arroyo (wash) – is a term applied in the arid and semi-arid southwestern United States to a small flat-
floored channel or gully usually with steep or vertical banks that form under certain conditions. Urban
development along arroyos can result in the release of relatively clean water to the system that increases
flood velocities and the rate of erosion.
4

Comprehensive Report and Program - 2020
Alluvial Fan – is a deposit of sediment occurring at the base of mountain ranges where the sediment has
eroded from the mountainside to form a gently sloping fan-shaped deposit. As the floodwaters near the
valleys, the velocity decreases, and the sediment begins to be deposited. Alluvial fans can contribute to
flooding problems because of their unpredictable nature. In addition, alluvial fan flows frequently shift their
position horizontally, known as lateral migration.
Lateral Migration – Streams have a natural tendency to shift as the channel evolves. Migration may occur
either vertically or horizontally, often encroaching on properties not originally located in harm’s way when
constructed. Bank erosion occurs when the main channel shifts its course, either for natural or human
induced reasons. Vertical channel migration is usually associated with aggradation (deposition), which
affects the stability of the stream. Alterations in the channel can cause severe changes in the capacity of the
channel to carry floodwaters and can affect peak flows and velocities.
Storm Events and Frequency
Climate
Maricopa County lies within a dry, subtropical desert climate zone. Average annual rainfall ranges from five
inches in the lower elevations to over 16 inches in the higher elevations. Approximately 95 percent of
Maricopa County is in the Sonoran Desert. Although the Sonoran Desert is lush compared to other deserts, the
average evaporation losses exceed the precipitation, which defines the area as a desert.
Precipitation
There are two distinct precipitation seasons. Winter storms occur from November to March when the region is
subjected to occasional frontal storms from the Pacific Ocean. The highest winter precipitation occurs when the
mid-latitude storm track is to the south. Southern-originating storms tend to enter Arizona directly from the west
or southwest after picking up considerable moisture from the Pacific Ocean.
The second rainfall season, also known as the North American Monsoon, is caused by a seasonal shift in wind
direction and occurs in July, August and most of September. Characteristics of this season include widespread
storm activity associated with moist air moving into Maricopa County from the south and southeast. These storms
vary in intensity and location, and some of the heaviest amounts of precipitation in a short period occur during
these months. Periodically, tropical storms in the eastern Pacific can influence our summer rainy season from the
months of August through October. This additional moisture can add both volume and duration to storms that
form over Maricopa County.
Rainfall records have been consistently retained for the Phoenix area for over 120 years. At Sky Harbor Airport
the 24-hour duration rainfall that would be estimated to occur in a 100-year (one percent probability) event would
be 3.30 inches; a 50-year (two percent probability) event would produce an estimated 2.93 inches. These
estimates vary throughout Maricopa County. In any given year Maricopa County experiences summer and winter
storms with the potential to generate flooding.
Currently, the District maintains 356 automatic rain gages, 218 automatic stream gages, and 40 automatic weather
stations at 409 locations throughout Maricopa and neighbouring counties, with the first of these stations being
installed in 1980. This system is still being expanded as information is needed in other locations. Map A shows
the location and coverage of this system. Data from these gages is available on the District’s website located at
www.maricopa.gov/625/Rainfall-Data.
Flooding in Maricopa County is typically caused by winter storms, tropical storms, or summer thunder storms.
5

Comprehensive Report and Program - 2020
1. Winter storms offer the greatest potential for damage on our largest watercourses. Since these storms
typically occur over several days and often combine with snow runoff from the high country, they saturate
soils and overwhelm the natural and built drainage capacity, resulting in significant flood damage in
developed areas. These storms usually cover a large geographic area, such as the January 2010 flood that
caused damage in parts of Cave Creek, Carefree, and north Scottsdale.
2. Tropical storms are derived from hurricanes in the Pacific. Tropical storms or hurricanes drop high volumes of
rainfall in a short duration, usually 12 to 36 hours. These storms cause the most damaging floods in watersheds
from 50 to 500 square miles in size. In 1997, record rainfall from Tropical Storm Nora caused two earthen dams
to break in Aguila, causing widespread flooding and the evacuation of approximately 40 people from the town.
Similarly the September 8, 2014 storm brought with it 1,000-year rainfall events to parts of the Valley,
inundating flood control infrastructure in Mesa and flooding some 400 homes.
3. As summer approaches, winds shift from a westerly to southerly direction, allowing moisture to stream into
Arizona from the Gulf of California or the Gulf of Mexico. Summer monsoon storms are typically short, intense,
and localized. Monsoon storms not only bring almost one-third to one-half of the annual rainfall in Maricopa
County, they can also cause flash floods, lightning, strong winds, dust storms, and hail. Monsoon storms have
caused significant property damage and several fatalities.
Types of Flooding
The type of flooding caused by a storm
event depends on the physical
conditions of the floodplain and
surrounding land, such as slope or soil
type. Development and other man-
made features or modifications to the
landscape can also alter the dynamics
of flooding. Most flooding events in
Maricopa County fall into one of three
major categories: riverine, alluvial fan,
and shallow flooding.
1. Riverine Flooding: Flooding that
occurs along a defined channel is
called riverine flooding. When a river
or wash receives too much water,
the excess flows over its banks and inundates the adjacent floodplain. Flash flooding can occur in a riverine
environment. A flash flood is a rapidly moving flood through low-lying areas such as washes and canyons. Flash
flooding can also occur in urban areas where impervious surfaces, gutters, and storm sewers accelerate runoff.
Flash floods occur after intense storms drop large amounts of rainfall in a short period of time. When this
happens, the ground cannot absorb the water fast enough so it accumulates in channels and flows downhill.
Flash floods are sometimes preceded by a debris flow that contains rocks, brush, logs and anything else it picks
up along the way. Flash floods are the leading cause of flood-related deaths in the United States because
they happen quickly and often without warning.
2. Alluvial Fan Flooding: Flooding that occurs in parts of the Valley with slopes between 2-16 percent. Alluvial
fans pose a significant public safety hazard. Areas within a fan are subject to flash flooding, high velocity flows,
debris flows, erosion, sediment movement and deposition. The public safety risk is intensified since the areas
6

Comprehensive Report and Program - 2020
where alluvial fan flooding occurs are attractive for development due to scenic value and proximity to
mountains.
3. Shallow Flooding: As defined by the National Flood Insurance Program (NFIP), shallow flooding occurs in flat
areas “where a lack of channels means water cannot drain away easily.” Shallow flood problems include sheet
flow and ponding. Sheet flow is a condition where storm water runoff forms a sheet of water to a uniform
depth. Sheet flooding is often found in areas where there are no clearly defined channels with slopes
less than two percent. Ponding typically occurs in low spots on the upstream side of roadways, canals,
railroads, and other embankments. The storm water remains in the depressions until the water evaporates or
seeps into the soil.
Flooding in Maricopa County occurs when natural waterways such as creeks, rivers and washes cannot contain
the flow of a rainfall event. The county's mountainous desert topography, compacted soil, and numerous
watercourses prevent rainfall from quickly soaking into the ground. Development that increases impervious
surfaces can worsen the impacts of flooding. Buildings, homes, paved streets and parking lots disrupt the natural
flow of water and prevent absorption into the ground, potentially creating inadequate drainage.
Functions of Natural Floodplains
Floodplains are the areas adjoining the channel of a watercourse that may be covered by water during a flood.
Floodplains provide natural flood and erosion control, water quality maintenance, groundwater recharge, and
wildlife and fish habitat. Floodplains also provide public opportunities for outdoor recreation, scientific study
and education, and enjoyment of scenery and open space. There are thousands of miles of rivers, washes and
delineated floodplains in Maricopa County as shown on Map B.
Floodwater conveyance and storage are among the most important hydraulic functions performed by
floodplains. Flows that exceed the capacity of a natural channel are temporarily stored within the floodplain, re-
enter the watercourse slowly as either surface or subsurface flows, and are then conveyed downstream in the
watershed. The capacity of natural floodplains for floodwater storage and conveyance helps minimize the
magnitude of flooding and the potential for flood-related damage.
Flooding is a natural process of river systems. All rivers overtop their banks at some time, inundating the river’s
floodplain. A flood event is only considered hazardous when the floodwaters threaten human life or property
generally due to development in the floodplain. Land within floodplains is attractive to agricultural and urban
development for many reasons, including natural beauty, density of vegetation, recreational purposes, and access
to fertile soil.
In addition to the physical and biological functions, floodplains enhance the livability of communities in Maricopa
County including scenic, recreation, and economic benefits. Minimally developed or natural floodplains and
associated open space provide an economic value to the community. The scenic values and recreation
opportunities inherent in natural floodplains and washes create ideal locations for outdoor activities, such as
hiking, biking, birding, and nature based education.
7

Comprehensive Report and Program - 2020
Floodplains and Development
Maricopa County and the surrounding region have unique physical and biological characteristics. Five major rivers
drain from mountain ranges that surround the northern and eastern part of Maricopa County. A sixth major
watercourse, Centennial Wash, is to the west. The Verde, Salt, Agua Fria, and Hassayampa Rivers flow into the
Gila River. These rivers, especially the Gila, Salt, and Verde, made settlement in Phoenix and Maricopa County
possible.
Over 100 years ago, what is now metropolitan Phoenix was a large agricultural community. Many floodplains,
especially along the Gila River, were converted to agriculture fields because of the proximity to water, and the
relatively fertile soil and flat land that is characteristic of floodplains. When converting desert to agricultural land,
farmers typically modified the natural drainage characteristics by grading the land and filling in the washes. As
the population grew, agricultural land was relatively easy to convert into residential development. As natural
drainage patterns and associated flooding hazards on agricultural land were not evident, people built houses in
these areas.
This pattern of development continued as communities grew. It is estimated that there are 8-12 million homes in
our nation’s floodplains. In Maricopa County there are an estimated 57,522 homes in delineated floodplains with
3,891 of those homes in delineated floodways. While a concern, homes in floodplains are a small portion of the
approximate 1.8 million housing units in the county as noted in 2018 Census statistics.
When the District was created in 1959 the population was approximately 663,510. 2010 Census population of
Maricopa County, including the incorporated cities, was 3,817,117. The current population estimate is 4.4 million
(July 1, 2018 Census estimate). Population continues to increase and development has replaced farmland,
sometimes occurring in areas outside the ring of dams and flood retarding structures built from 1953-1988.
Development in steeper terrain where sudden flash flooding hazards exist for structures and the traveling public
adds to the risk.
8

Comprehensive Report and Program - 2020
Repetitive Loss Areas
Repetitive loss areas are properties within the county that have been damaged by flooding two or more times.
Federal Emergency Management Agency (FEMA) requires communities to identify repetitive loss areas and notify
residents annually that they are located in these repetitive loss areas. There are seven federally-recognized
repetitive loss areas in Maricopa County that include over 200 properties. The general areas are shown on Map
C.
 Watson Road and MC 85 in Buckeye
 North 40th Street and East Dynamite Boulevard in Cave Creek
 43rd Avenue and West Carver Road and 51st Avenue and West Olney Avenue in Laveen
 West Glendale Avenue and West Sarival Road in Litchfield Park
 North 36th Avenue and West Old Stagecoach Road in New River
 27th Avenue and West Dobbins Road in Phoenix
 South 194th Street and East San Tan Boulevard in Queen Creek
Flood History
The vastness of Maricopa County, unique geography, and storm patterns combined with rapid development and
growth contributes to community flood risk. As witnessed during the 2014 Monsoon, rapid runoff from mountain
areas, storage of floodwater in the floodplain, sheet flow, and ponding in low areas where development exists
remind us of the flooding problems that impact infrastructure, residences, and economic functions. The residents
and visitors to Maricopa County were reminded again of these flooding hazards during significant storm events in
July 2015, October 2018, and September 2019.
Since 1966, Maricopa County has been declared a flood disaster area 20 times, with the latest being for the
September 8-9, 2014 event. There was approximately $2.5 million dollars in damage to District facilities,
considerable damage to roadways and hundreds of homes flooded in various parts of Maricopa County. In the 50
years from 1959 through 2009, flood events have inflicted more than $1.5 billion in damages. A summary of the
damage from the 2014 storm was prepared for the 2015 Multi-Jurisdictional Hazard Mitigation Plan for Maricopa
County. Table 1 provides an overview of major floods and past flooding damage from 1891 to present.
9

Comprehensive Report and Program - 2020
Existing Flood Control Facilities and Programs
Large Regional Structures
In response to the frequency and extent of past flooding in Maricopa County, the District and other agencies have
built a number of flood control structures. Many of these structures were constructed primarily for flood control.
Others, such as dikes on the upstream side of the Central Arizona Project (CAP) canal, were built for different
purposes but have indirectly contributed to some measure of flood control. Since the District’s inception in 1959,
numerous channels, basins, storm drains, and other structures have been completed. Table 2 lists all the
proposed projects to mitigate the flooding problems identified in the 1963 Comprehensive Report. Many of these
projects were turned over to the municipal (city) partners to maintain after completion. Dams, flood retarding
structures, and levees built by the federal government or District are listed in Tables 3 and 4.
The District ensures the reliability, safety, and structural efficiency of more than 80 flood control structures
throughout the 9,226 square miles of Maricopa County. These structures include 22 dams, 370 acres of basins,
41 miles of lined channels, 81 miles of unlined channels and more than 60 additional structures, including levees
and drains. The District manages four flood control dams (dams) under operating agreements with the U.S. Army
Corps of Engineers (USACE) and sixteen flood control dams (flood retarding structures – FRS) under operating
agreements with the Natural Resources Conservation Service (NRCS). In addition, the District owns and manages
Casandro Wash Dam within the Town of Wickenburg and McMicken Dam (constructed by USACE but now
managed by the District), and manages 24 levees.
Planning – Flood Hazard Identification
The District’s planning program emphasizes a regional, uniform, and coordinated approach to identifying flooding
hazards and proposing solutions. Area Drainage Master Studies (ADMS) are intended to inform development
plans and drainage criteria for use by the development community, and to identify flooding hazards which, when
working with the local community may result in the identification of structural mitigation solutions for specific
flooding hazards, through the Area Drainage Master Plan (ADMP) process. The objective is to plan and facilitate
implementation of flood control projects in the shortest time possible coupled with the lowest total cost, while
balancing social and environmental considerations. A second important goal of the planning program is to identify
potential flood control and stormwater management problems prior to the onset of new development. The
objective of this goal, through sound planning, is to avoid or minimize the future need for publicly-funded
structural flood control projects.
ADMS’s and ADMP’s are completed and implemented by the District to mitigate flooding and drainage hazards
within the county through promoting awareness, developing structural solution concepts, and recommending the
construction of structural projects to reduce risks. In order to determine the location and need for flood control
structures and other means of reducing the impact of floods in Maricopa County, the District has conducted flood
hazard identification studies for over 46 percent (3,841 square miles) of the county.
10

Comprehensive Report and Program - 2020
Public Meetings and Organization Outreach
The District has either completed or is
currently working on 19 ADMS/P since
January 2015. As a part of the outreach
activities for these studies, a total of 39
Public Meetings were held at different
parts of the respective communities within
Maricopa County. Additionally, these
studies also warranted 40 individual Home
Owner Association (HOA) and/or
Community meetings during the same five
year period.
During the next five years, 15 additional
ADMS/P are scheduled to be updated
which includes more than 30 Public
Meetings as part of planned outreach
activities. The number of HOA and/or Community meetings are unknown at this time, which will be held subject
to specific needs as identified by the ADMS/P.
Floodplain Delineation Studies (FDS) are completed as part of ADMS’s or done independently on washes to
identify the hazard area preferably before development occurs in and around the watercourses. In some cases,
watercourses are re-delineated as new technology and data are available and to reflect changes to the watershed
or observed rainfall that may have occurred over time. Floodplain delineation studies have been completed for
approximately 4,000 lineal miles of county rivers and washes. ADMS and FDS completion represents one of the
key opportunities for the District to forecast and defend against hazardous flooding, particularly as the county
population grows and development increases. Map D show the ADMS’s that have been completed and are in
process and Map E indicates future floodplain delineation studies.
Capital Improvement Program
Since the creation of the District in 1959, over 65 flood identification studies have been completed and more than
150 flood control projects have been built. In addition, over 350 projects have been identified through the yearly
CIP prioritization procedure. During this timeframe, the county’s population has grown by over 3 million. Maps
F1 and F2 show the completed projects through Fiscal Year 2019.
The projects built through Fiscal Year 2019, represent an investment of over $2.6 billion county-wide for flood
protection. Many of these projects, in addition to flood protection, enhance the area and provide for recreation
activities. A full list of these projects are found in Table 6 and are shown on Maps F1 and F2. The District is still
completing projects identified from prior years. The 358 potential projects identified to date total nearly $2.3
billion and were submitted from ADMS’s and partners. Map G shows the projects, or project areas, identified in
the current five-year CIP. Many of these projects were submitted in response to the flooding and intense storms
in August and September of 2014. Responses received from 17 partners totaled in $1.53 billion dollars in requests.
Arizona Revised Statutes require that a five-year Capital Improvement Program (CIP) be prepared and approved
by the Board of Directors (BOD). The program shall separately identify capital improvements for engineering,
rights-of-way and land acquisition and construction with such supporting explanations, cost estimates and
completion schedules as the BOD may require. A separate five-year Capital improvement Program document is
presented to the BOD every year for adoption.
11

Comprehensive Report and Program - 2020
Annually, the District solicits proposals from cities and towns for countywide capital projects that provide regional
flood control benefits. The projects ideally contribute to community development, maintain the benefits of
existing watercourses, help protect natural habitat and landscapes, and provide multiple-use opportunities for
our citizens and visitors. Funds are directed through the five-year CIP. From Fiscal Years 2000 through 2020, the
District received and reviewed 358 CIP proposals. 149 of these proposals were included in the CIP, and 81 of these
projects have been completed. An additional four projects are underway and portions of 15 other projects have
been partially constructed. For Fiscal Year 2020, the District is committed to funding 26 CIP projects.
Small Projects Assistance Program
Localized historic flooding hazards can be more efficiently mitigated through smaller, local projects that would
not be a high priority under the yearly CIP. In 2009, the District and municipal stakeholders recognized the
demand for smaller, more cost effective capital projects and developed the Small Project Assistance Program
(SPAP), providing an option for rapid implementation of local drainage projects. The program was revised March
2015 to allow small projects in unincorporated county. In September 2019 funding levels were increased for
projects submitted to the SPAP.
From 2011 through 2019, the District received and reviewed 119 SPAP proposals, 77 of which were eligible for
funding and 64 of which have been constructed. For Fiscal Year 2019, the District committed to seven SPAP
projects. The District committed to zero projects for Fiscal Year 2020 due to zero submittals. However, the
preliminary Fiscal Year 2021 program contains ten SPAP projects.
Floodprone Property Assistance Program
A Floodprone Properties Acquisition Program was adopted by the Board in 1995 and has been updated several
times. The Floodprone Properties Assistance Program (FPAP) was revised and adopted in 2006 to include flood
proofing where feasible. Since the last program revisions, nine homes in high risk areas have been removed
from floodways and floodplains. The FPAP was revised in March 2015. Participation in this program is strictly
voluntary; interested homeowners may submit an application directly to the District for consideration. A
collective total of 78 residences and associated property have been purchased through the FPAP program, which
includes the 1995 buyout, a 2001 mitigation buyout by FEMA after flooding in Aguila, and the latest buyout in
the New River area after flooding in the area in 2019.
12

Comprehensive Report and Program - 2020
Dam Safety Program
The District operates and maintains 22 flood control dams, protecting significant portions of Maricopa County.
Most of these dams are the main flood control features of federal flood control projects for which the District was
the local sponsor. The District systematically assesses, repairs, and rehabilitates these dams.
All District dam rehabilitation and dam modification funding are included in the CIP. With the completion of the
White Tanks FRS No. 3 Dam Rehabilitation Project in 2011 and the completion of the Spook Hill FRS Rehabilitation
Project in 2008, nine dams now remain to be rehabilitated or modified. The District is partnering with the NRCS
for cost sharing of most of the dam rehabilitation projects - cost share split is generally 65 percent federal and 35
percent local. To date, the District has received approximately $100 million in obligated federal funding from
NRCS for dam rehabilitation. Table 3 lists these dams and FRS’s and the current status of projects underway.
Prolonging the life of District dams through overall rehabilitation provides significant long-term flood protection
benefits to downstream communities. For example, the benefit to cost ratio of the Spook Hill FRS Rehabilitation
Project was estimated to be 56 to 1, with estimated average annual flood damage reduction benefits of $23 million
per year.
Through routine assessment and evaluation of the physical condition of the District’s 22 dams and related
features, continued compliance with current regulations is assured. Implementation of short term and interim
term measures to improve the operation and proper functioning of the dams is performed in addition to normal
operations and maintenance requirements. Site-specific dam safety issues are investigated and repaired or
corrected as needed. Overall dam rehabilitations typically cost in the tens of millions of dollars and can take many
years to fund and complete. The Dam Safety Program ensures dams are kept safely in service until rehabilitation
funds can be obtained and rehabilitation projects can be planned, designed and constructed.
Levee Safety Program
The District’s Levee Safety Program was established in 2018. The District manages, inspects, rehabilitates, and
proactively plans for flooding emergency management. District levees comprise earthen embankments, soil
cement structures or floodwalls that contain, control, or divert the flow of water so as to mitigate the impacts of
temporary flooding. This floodplain benefit is officially recognized by FEMA on their Flood Insurance Rate Maps.
The District is responsible for the operation and maintenance of 26 levees across the County. Currently, the 39
miles of District levees provide a floodplain benefit to a total of 20,900 acres. The objective is for all District levees
to meet federal requirements and the ones regulated by FEMA are accredited by FEMA as a result of the District’s
engineering efforts for levee certification.
Many of the levees operated by the District were built in the 1970’s and 1980’s when the federal government’s
levee focus was more on floodplain delineation and FEMA’s levee certification standards were not yet
implemented. Now, the District is taking new measures to address more rigorous federal requirements for levee
operation and maintenance, revised flood insurance maps, and increased knowledge about potential levee
failures. At the same time, the District is looking ahead at how its levees now function due to their age.
A key element of improving public safety and reducing flood risks is communication with other local levee
sponsors, impacted communities and the public on the overall condition of levee systems, with planned
maintenance and improved emergency response actions. Emergency Action Plans are developed for District
levees. All levees are inspected on a three-year rotating basis as part of the formal and comprehensive Levee
Safety Program. Levee pipe penetrations (storm drains, etc.) are inspected every five years. This work is
13

Comprehensive Report and Program - 2020
supplemented by regular inspections, maintenance and rehabilitation as may be required by the inspection
findings. Inspection status is provided in Table 4. On an as-needed basis the District completes a comprehensive
investigation of a levee’s features with consideration of possible failure methods.
Operations and Maintenance
The District has taken on the maintenance of 23 federally built structures, while the maintenance responsibility
for 90 structures out of the 158 have been turned over to our project partners. The District operates, maintains
and fully manages 90 flood control structures, including 22 dams/flood retarding structures totalling 64 miles in
length, 150 miles of channels and levees, 250 acres of basins and 40 acres of general flood hazard mitigation
property. Flood control structures require regular inspections and maintenance to function as designed and
provide the maximum flood protection. This year the District is adding the 115th Avenue and Union Hills Drive
Drainage Improvements project to the maintenance program. This structure is one mile in length. As District
structures approach the end of their design life, maintenance costs will continue to increase.
Other maintenance efforts include dam safety inspections, outlet pipe inspections, field surveys, land subsidence
monitoring, and earth fissure monitoring. Dam safety inspections are performed on an annual basis by District
staff. Inspections of outlet pipes by video camera are performed every five years. Field surveys of dams are
required to monitor physical changes due to embankment and foundation settlement and land subsidence.
Additionally, pre- and post-storm event inspections are performed to assure structures function as designed
during an event and any needed maintenance is addressed.
Other Mitigation Efforts
Emergency Action Plans (EAP) are required for all jurisdictional dams by the State of Arizona and are updated
periodically under consultant contracts or in-house. Table 5 provides a list of EAP’s, type and when last updated.
EAP’s are also being developed for levees as part of the FEMA Levee Certification program. While the EAP’s do
not physically protect property and lives, they provide a warning and plan of action to move people out of harm’s
way during flood emergencies.
Flood Response Plan
The Flood Control District of Maricopa County (District) provides flood hazard identification, prevention,
regulation and remediation to reduce the risk of injury, loss of life and property damage from flooding in the
County. The District currently has 11 Flood Response Plans (FRPs) and the purpose of a comprehensive FRP is to
ultimately reduce the potential for property damage and loss of life resulting from floods in Maricopa
County. These plans have action protocols for effective and efficient response to levels of flooding alert status of
increasing hazard and severity.
Multi-Use Opportunities
The District seeks to balance the beneficial functions
and resources of natural floodplains with the need
to protect life, property, and infrastructure. This is
accomplished through a proactive multi-objective
planning and design process that considers flooding,
community, and ecosystem concerns. Constructed
flood control facilities can replicate some of the
“natural” functions of floodplains - if designed and
built in a sustainable, sensitive manner.
14

Comprehensive Report and Program - 2020
The District has made a commitment that new flood control projects not only help protect people and property
from flooding hazards, but also recognize stormwater as a valuable community resource and provide beneficial
opportunities for multi-purpose uses. These benefits may include open space preservation, increased
protection/restoration of natural landscapes/habitat, improved recreational facilities, and aesthetically pleasing
designs that contribute to the environment of community well-being and revitalize urban areas. One of the goals
of the District is to design and construct facilities that incorporate multiple use and natural resource preservation
opportunities. Projects such as the Lower El Mirage Wash Basin and Storm Drain, Bethany Home Outfall Channel,
and White Tanks #3 Outfall Channel are examples of some of the approaches the District takes to partner with
communities to provide structures with flood protection and multi-use recreational benefits to the region.
Additionally, the District is expanding efforts beyond the native tall pot tree program (District-grown, deep-rooted
native trees minimizing potable watering needs) to incorporate other valuable tools and green infrastructure/low
impact development techniques for water conservation, integrated stormwater management, and increased
infiltration/recharge potential at existing and future structural facilities.
Water Conservation, Alternative Stormwater Management, and Green Infrastructure/Low Impact
Development Strategies
As the District’s work evolves away from larger, regional
flood control facilities and continues in our commitment to
address partner agency flooding issues in their urbanized
environments, we remain flexible in our approaches by
incorporating additional tools and technologies to help do
our work. Water conservation and flood control are
integrative resource management strategies for the same
vital resource. Accordingly, the District is continuing to
employ water conservation strategies, alternative
stormwater management, and Green Infrastructure/Low
Impact Development (GI/LID) techniques on our projects
when possible and is seeking to better understand, not
only their value to peak flow and volume reduction during multiple-scale storm events but also, the secondary
benefits imparted to the communities where we work on water augmentation, urban heat and shade, air quality,
healthy communities, and viable economic growth.
The District has designed and constructed multiple structures with earthen, vegetated channels, and sediment
and water harvesting swales/basins as part of our CIP program. Our CIP and SPAP programs now include
opportunities for additional points during project application scoring and evaluation for those projects that
provide ancillary benefits for water conservation/recharge, multiple use functionality, community economic
impact, water quality, vegetation/wildlife enhancement, community quality of life, and alternative stormwater
management strategy implementation, such as GI/LID features.
The District continues to work on improving internal standards and guidelines to promote and encourage water
conservation and use of alternative stormwater management techniques, including development of the Rio Verde
Alternative Stormwater Management guiding document for rural County property owners seeking to implement
water conservation, nuisance flooding protection measures, and land management strategies. The District is
evaluating existing structures to assess recharge and other water conservation potential opportunities as part of
our flood control facility function. The District is preparing construction plans for the Durango Campus Landscape
and Water Conservation Retrofit project to reduce potable water use on outdoor uses, to educate on water
conservation and integrated stormwater management strategies, and to showcase the functional benefit of a
suite of green infrastructure and water-harvesting techniques to the general public and professional staff alike.
15

Comprehensive Report and Program - 2020
Outreach and Notification
Flood Warning
District programs are in place to provide county residents and organizations with early warning of flooding.
District outreach takes several forms – via the District website, the Meteorological Service Program (MSP), and
through social media. The District’s website provides up-to-the-minute and historic rainfall, stream flow,
impoundment, and weather data from 400 plus environmental monitoring sites throughout Maricopa County and
surrounding counties. The MSP provides daily weather forecasts, flood watches and flood warnings tailored for
more than 133 emergency response agencies and recreation safety officials at all levels of government, allowing
longer lead-times and more accurate responses to many different hazards, including flooding. Additionally, the
District distributes real-time storm event information via social media. Facebook and Twitter accounts allow
‘followers’ information on rainfall rates and locations, hazardous conditions due to flooding, storm formation and
motion, and forecast availability.
Flashing Road Signs
Almost half of all flash flood fatalities occur in
vehicles that have entered flooded
roadways. Our mission is to reduce this
statistic by properly alerting the public to
dangerous water hazards. In conjunction with
Maricopa County Department of
Transportation, the District currently operates
seven pairs of flashing roadway signs within the
County. “DO NOT CROSS WHEN FLOODED”
signs are placed before low-water crossing
flash to alert motorist when dangerous
flooding is imminent or already
occurring. District ALERT sensors gather real-
time information on flow conditions. If data suggest flooding is imminent, the flashing light is triggered by a radio
signal from a gage. This services as a first response to drivers during storms.
Communication and Outreach
The District uses multiple communication and
outreach techniques to promote flood safety and
responsibility. In addition to traditional avenues
like advertisements via radio, newspapers,
television and billboards, the District also manages
Twitter, Facebook, Instagram and YouTube social
media accounts. Since being launched in June
2014, the District’s social media accounts have
created instantaneous two-way communication
with the media, residents and stakeholders
throughout the County. The County’s recent
website redesign was completed to make the most
sought after online services more readily available
to the public. The District’s website is managed to
ensure the public receives weather, storm
16

Comprehensive Report and Program - 2020
resources, flood insurance and floodplain information in an easy-to-navigate format. Additionally, STEM-focused
curriculum and classroom appearances have increased the District’s visibility in elementary and junior high
schools. Those efforts are being coupled with the development of an interactive website and youth-centered
characters to help promote flood safety to the County’s youngest residents.
Floodplain Management
From 2015 through 2019 District staff responded to over 14,000 customer inquiries about flood insurance,
property in a floodplain, general flood information, and specifics about permitting. Staff provide maps and
information for owners to give to lenders and insurance companies; research parcels regarding flood insurance
needs; and meet with customers in the office and field to discuss what can be developed in the floodplains. Staff
also visit properties after storm events to see drainage patterns and flood damage, offer FEMA information on
floodproofing and other protection for future development. The District also performs floodplain management
for 14 of the 25 cities and towns in Maricopa County (District Dependent Communities) which includes: City of
Buckeye, Town of Carefree, Town of Cave Creek, City of Chandler, City of El Mirage, Town of Gila Bend, Town of
Guadalupe, City of Litchfield Park, City of Mesa, Town of Queen Creek, City of Surprise, City of Tolleson, Town of
Wickenburg, and Town of Youngtown. Duties include issuing floodplain use permits, assisting with FEMA audits
for the National Flood Insurance Program and Community Rating System, and offering floodplain expertise and
enforcement as needed by the community.
17

Comprehensive Report and Program - 2020
Recommendations
Cooperation Between the District and Owner(s) of Existing Facilities
Federal
The District coordinates with multiple federal, state and local agencies to implement the requirements of the
Federal Emergency Management Agency (FEMA), the USACE, the Arizona Department of Water Resources
(ADWR), and other state and county programs. As noted in Tables 3 and 4 the District manages a number of
federally built structures. The District also coordinates with the NRCS (formally the Soil Conservation Service) on
rehabilitating nine major flood control dams (two completed, four ongoing and three future), that now protect
large areas.
Most of the flood control projects in the early years of the District’s operation were constructed through cost
sharing agreements with federal agencies. In most instances the federal cost share partner paid for project
construction and the District furnished the land on which the structure was built. Once the project was completed,
the District, as the local sponsor, was required by formal agreement to operate and maintain the project features
and to perform other Project management responsibilities as needed for the life of the structures. These
responsibilities include inspections for dam and levee safety, land management, flood monitoring and warning
and EAPs. Federal funding for new flood control projects has been steadily declining and decreasing in the last
twenty years as federal budgets have been reduced. Today, with the recent exception of NRCS funding for dam
rehabilitation projects, most cost sharing has been with local municipalities and county agencies, with limited
monies from various state agencies. However, the District is currently working with the USACE on possible funding
support for Cave Buttes and McMicken Dams rehabilitation projects.
USACE – The District manages four USACE dams under operating agreements with the USACE. The District
participates in the USACE Rehabilitation Program (RP) funded by Public Law PL84-99 for many of its flood control
dams and levees. There are 18 levees (70 percent of total) and six dams (27 percent of total) that are currently in
the Rehabilitation Program and eligible for flood damage repair assistance. The District regularly inspects all
structures while the USACE performs periodic levee inspections on approximately a five-year cycle. The District
provides all funding for levee maintenance unless there is substantial storm damage. Except for Centennial Wash
Levee, all of the District’s levees meet federal standards and are accredited by FEMA as a result of the District’s
engineering efforts for levee certification. The USACE typically inspects their six dams annually.
FEMA – Cooperating Technical Partner (CTP)
The District has participated in FEMA’s CTP program since 2001. During that time the District and FEMA
collaborated to update all the Flood Insurance Rate Maps (FIRMs) for Maricopa County that became effective in
2005, and in 2015 coordinated on a partial update of 100 FIRM panels out of over 300 total panels for the county.
The District and FEMA have also partnered on several floodplain delineation studies in order to identify those
areas vulnerable to flooding. In 2014, the District entered into a CTP agreement with FEMA to develop two ADMS
and the data needed for FEMA’s Risk Mapping, Assessment and Planning (Risk MAP) program. FEMA is working
with federal, state, tribal and local partners across the nation to identify flood risk and help reduce that risk
through the Risk MAP program. Risk MAP provides high quality flood maps, information, and tools to better assess
the risk from flooding to communities to help them take action to reduce (or mitigate) flood risk. In 2019, the
District entered into a CTP agreement with FEMA to perform a floodplain delineation along Vekol Wash and its
tributaries.
18

Comprehensive Report and Program - 2020
State
Arizona Department of Water Resources is the regulatory authority for the 22 flood control dams managed by the
District. Typically ADWR attends annual inspections performed by the District, prepares its own inspection reports,
and issues dam safety deficiency notifications under various classifications of severity. All ADWR dam safety
deficiencies are actively being addressed through dam rehabilitation projects. ADWR issues permits for District
dam rehabilitation projects, which can be obtained only after a highly rigorous review process.
Over the years the District has had occasion to work cooperatively with the Arizona Department of Transportation
(ADOT) on a number of flood control projects. In the 1980s/1990s the District partnered with ADOT, Phoenix,
Tempe and the Salt River Pima – Maricopa Indian Community (SRPMIC) on the design and construction of the
channelization of the Salt River from the Sky Harbor Airport upstream to the Indian community. Additional
examples of collaboration include the Loop 202 project in the east valley. This impacted the existing Spook Hill
flood retarding structure, the District and ADOT entered into a partnership that included improvements to the
Spook Hill FRS which also accommodated the freeway. The District also worked with ADOT as part of the Loop
303 freeway project to include improvements to the freeway drainage channel, increasing its capacity allowing
the channel to function as a regional storm water drainage facility. District staff are communicating with ADOT
on any future collaboration on the western portion of the Loop 202 and State Routes 24 and 30.
Local
The cities and towns in Maricopa County, including unincorporated county, must have a FEMA-approved local
mitigation plan in order to receive project grants. The Maricopa County Multi-Jurisdictional Hazard Mitigation
Plan outlines the jurisdiction’s commitment to reduce risks from natural hazards and serves as a guide for decision
makers as they commit resources. Maricopa County Department of Emergency Management takes the lead on
this Plan and along with the District, other participating jurisdictions, tribal nations, and Salt River Project
completed the first Plan. A full update is required every five years by FEMA and the current Plan was approved in
December 2015. Maricopa County Department of Emergency Management is currently updating the 2020 Plan.
Generally new projects are partnered with our customer cities and towns. Through the CIP prioritization process
(CIPPP), requested projects are evaluated and may be recommended for future funding. When project partner
interest and funding becomes available, intergovernmental agreements will be developed allowing a project to
move forward through design and eventual construction. The responsibility for operation and maintenance of a
completed project most always falls to the project partner and local jurisdiction where the project is located. The
District also partners with cities and towns on ADMS’s and delineation studies that often cross multiple
jurisdictional boundaries.
Over the past 10 years the District has partnered with MCDOT on a program to barricade roads that flood. MCDOT
funded approximately two dozen ALERT gages upstream of hazardous road crossing to give advanced warning of
flooding. These gages are displayed continuously on MCDOT’s Traffic Management Center. Also, the District has
embarked on a program to install signs with flashing lights to warn motorists of an impending flood at hazardous
crossings. The flashing signs are activated automatically by either an upstream rain or stream gage. Currently,
seven sets of these signs are installed with more planned as situations demand.
Private
Regional flood control facilities are typically designed to address flood hazards that are beyond the scope of what
private developers may be required to perform. Developers and property owners are invited to attend and
participate in meetings to provide input and feedback on project design. When rights-of-way for a facility are
required through an existing or future development, the District works with and coordinates facility designs, road
crossings, and rights-of-way needs with the developer’s land plan or existing features. In certain instances, the
19

Comprehensive Report and Program - 2020
District has entered into cost-share agreements with developers to construct road and utility crossings of the
facility to avoid more expensive retrofits or culvert extensions by the developer later on.
Preliminary Plan for Construction or Acquisition of Facilities
Capital Hazard Identification and Mitigation Programs
To address the design, construction, and acquisition of infrastructure to carry out the purpose of the District, a
five-year capital improvement plan (CIP) is updated each year. In conjunction with the five-year plan, a general
overview is created to show facts and figures along with project descriptions, schedules, estimated costs, maps,
and partnering information. Map G shows the capital improvement projects, or the area for multiple projects, for
FY 2021 - FY2024. Details of these projects can be found on the District’s web page.
Major Maintenance Programs
In response to aging infrastructure the District added Major Maintenance to the capital improvement fund in
Fiscal Year 2019. This will allow the District to manage maintenance projects too large for the operating budget
but not large enough to be a full scale capital improvement project. These are projects strictly funded by the
District with no partner funding.
Other Programs
In addition to capital projects, the District has a variety of other programs that provide different strategies for
mitigating flood hazards. The Floodprone Properties
Assistance Program (FPAP), established in 1995 and
updated several times, is a voluntary program where a
residential structure located in the floodway or having
experienced flood damage in the floodplain could be
purchased by the District and demolished. Property
Owners receive payment for the property and
incidental funds for relocation. An additional tool was
added in 2006 to the FPAP to allow floodproofing if
feasible. This allows owners to stay in the same
location but the structure is elevated or floodproofed
to mitigate flood damage.
Funding for the FPAP is contingent on availability of funds and community need. Within Maricopa County there
are currently an estimated 57,522 homes in the floodplain with 3,543 of those homes in the floodway. A portion
of these structures were built after floodplain delineation and meet regulatory standards so risk is reduced.
Revisions to the FPAP in 2015 included a cap on the amount for each property purchase and relocation costs, and
refined the qualifying criteria.
The Small Projects Assistance Program (SPAP) provides up to $500,000 matching dollars toward more localized
solutions for cities and towns, and now unincorporated county, to mitigate smaller flooding problems.
Amendments to the SPAP were adopted by the Board of Directors March 25, 2015. The SPAP was amended to
allow implementation of small projects within unincorporated Maricopa County. Previously projects could only
be submitted for incorporated areas. The funding increase to $500,000 was approved by the BOD in 2019 in
conjunction with other amendments.
The Capital Improvement Program Prioritization Criteria evaluates proposed structural projects on their merits
based on specific criteria. Recommendations to several District policies were requested from the BOD during the
20

Comprehensive Report and Program - 2020
2014 Strategic Planning and Budget process. Changes have been made to the CIPPP and approved by the BOD
that adjusts points received for various criteria in the CIPPP process. The most significant point change is for the
criteria that emphasizes the need for project cost share from the submitting agency.
Funding
Revenue from the secondary property tax (FY 2020 rate of $0.1792 per $100 of assessed valuation) is the Districts
main source of income. Other sources include partner cost share, in lieu of taxes, grants and other minor funding
sources. The District’s total revenues for FY 2020 were $76.0 million, including $69.9 million in property tax
revenue. Expenditures for the District are managed through various categories including: Operating, CIP, Major
Maintenance, SPAP, FPAP and Non-Recurring Projects. Expenditures in the Operating budget are generally
consistent year over year; however, the other categories can experience significant variations depending on the
projects in process, needs of the various communities as well as responses to storm damage. In FY 2020, total
expenditures were $76.6 million of which $27.5 million was operating, $41.5 million in CIP and $3.4 million in
Major Maintenance.
Intergovernmental Participation
Revenue generated from intergovernmental agreements can fluctuate greatly. Current revenue from
partnerships is anticipated from federal partners (NRCS) for rehabilitation of dams, as well as cities and
towns. Participation revenue from cities and towns for the past five fiscal years has declined on an annual
basis. Cost share on structural projects is typically 50/50 with other agencies.
Additional Funding Resources
During the Strategic Planning process in 2014 the BOD recommended the District staff explore all funding
opportunities. District staff continue to apply for grant opportunities when appropriate. Almost all programs and
grants require a District funding match. The following is a list of potential funding opportunities:
• Regional Conservation Partnership Program
• Water Infrastructure and Resiliency Finance Center
• Qualified Public Infrastructure Bonds
• Five Star and Urban Waters Restoration Grant Program
• Hazard Mitigation Grant Program
• Pre-Disaster Mitigation Grant Program
• Flood Mitigation Assistance Program
• Preparedness (Non-Disaster) Grants
Summary
During the early years of the District, the focus was on designing and constructing large regional facilities to
alleviate widespread flooding due to rapid development in the 1950’s. In addition, the Soil Conservation Service,
now the NRCS, built several large structures to protect farmland on the periphery of the urban area. These areas
are now largely urbanized and the dams transferred to the District are essentially protecting lives and structures.
The District functions have continued to evolve over the 60 years since its creation. While regional structures are
still needed in urbanized areas to address the development from earlier decades, these structures now serve
multi-use opportunities such as recreation, trails, and open spaces. Projects are completed in partnership with
many agencies and the District is continuing to expand on these opportunities. Additionally, other programs such
as FPAP and SPAP give the District tools to use when regional structures are not feasible.
21

Comprehensive Report and Program - 2020
The District ALERT system, Emergency Action Plans, Flood Response Plans, and continued diligence toward
keeping the structures, dams, and levees maintained provides continued protection to residents and visitors to
Maricopa County. Never was this more evident than during the 2014 Monsoon and subsequent significant storms.
The success of the many structures built over time that performed their designed function kept millions protected
from the numerous large storms from August through September 2014. Homes located in the floodway that had
been purchased years earlier through the FPAP would have received considerable damage if they had not been
removed and if washed downstream may have damaged other property. Real time data on rainfall, dam
impoundment, and streamflow was in the hands of law enforcement and emergency responders through the
District’s mobile applications and website. Emergency Actions Plans for dams and communities are available and
regularly updated in the event an evacuation is needed. The positive results of annual practice flood drills and
regular maintenance of structures was realized in 2014 when teams manned their stations and mobilized to the
field to get information out, monitor structures to assure the public was protected.
22

Comprehensive Report and Program - 2020
Program for Carrying Out the Regulatory Functions
Floodplain Regulations
Arizona Revised Statutes Sections 48-3601 through 48-3650 direct each county Flood Control District Board of
Directors to adopt and enforce floodplain regulations consistent with criteria adopted by the Director of Arizona
Department of Water Resources. The floodplain regulations adopted by a district are intended to carry out the
requirements of the National Flood Insurance Program (NFIP) set forth in 44 Code of Federal Regulations parts 59
through 78, as effective on January 1, 2005. In 1973, the State of Arizona passed legislation that authorized cities,
towns and counties to adopt floodplain regulations for the management of watercourses within their jurisdictions.
The District adopted the Floodplain Regulations for Maricopa County February 25, 1974. The Regulations are
reviewed periodically and were last updated on January 17, 2018 to keep current with federal policy and local
conditions. These Regulations apply to unincorporated county and the 14 District Dependent Communities.
The District regulates development in the delineated floodplains for unincorporated county and 14 District
Dependent Communities within the county. The remaining 11 cities and towns assumed the powers and duties
of their own floodplain management by adopting Resolutions stating their intent to assume functions of
permitting and enforcement including the adoption of floodplain management regulations. Regulations require
floodplain use permits, under certain circumstances, and allow for inspections, and enforcement. Floodplain Use
Permits for development in unincorporated county is performed by the County Planning and Development
Department. When regulating floodplains, the District first identifies flood-prone areas through floodplain
delineations and then limits or restricts land use within those areas. These activities, in addition to others, earn
flood insurance premium reduction credits for unincorporated county residents through the NFIP-Community
Rating System program.
The Floodplain Regulations for Maricopa County are designed to ensure that proposed development is free from
flood damage during the one-percent annual chance flood, and does not cause damage to other properties.
Reduction of the risk to life and property is also achieved through compliance inspections in conjunction with
approved permits. Once development has occurred in a floodplain District staff will continue a long-term
relationship with property owners responding to inquiries on flood insurance, providing documents from these
permits to future owners, visiting sites after storm events, and providing information for any additional
development.
Sand and Gravel Operations in the Floodplain
The District has regulated sand and gravel mining within watercourses since February 25, 1974, when the county’s
first floodplain regulations were established. Like all other floodplain activities, sand and gravel mining regulations
are based on federal and state requirements for floodplain management. The Floodplain Regulations for
Maricopa County define development standards and permit requirements for sand and gravel excavation within
flood zones.
Unincorporated County
Approximately 300-400 applications are reviewed for Floodplain Use Permits for unincorporated county each
year. During the building boom of 2005-2007, Floodplain Use Permits applications exceeded 1,000 each year.
Dependent Communities
Approximately 300-400 Floodplain Use Permits are processed annually for the 14 communities that the District
does floodplain management for. Applicants start at the community which checks for floodplains on parcels. If
23

Comprehensive Report and Program - 2020
property is in the floodplain the community refers them to the District. Applicants can submit electronically to
the District or apply in person. Permits are issued to the applicant and a copy sent to the community.
District Property
The District owns 26,431 acres of property held in fee title, and controls an additional 28,699 acres of property
via various easement interests, in support of the numerous structures we operate and maintain. Often utilities
and other services need to access District property to extend infrastructure. Permission from the District is
required to enter the property and to construct. Easements may need to be issued and the project will be
reviewed by District staff to assure that District structures will not be damaged or compromised due to the project.
Of this land area, 17,211 acres (65 percent) of the property held in fee and 14,830 acres (52 percent) with
easement interests are in designated floodplains and a Floodplain Use Permit is required before work can be
performed.
Enforcement
Article Seven of the Floodplain Regulations describes the process for enforcing the Regulations and establishing
compliance, to assure that property owners build safely, structures are not damaged by flooding, and that
surrounding properties are not adversely affected. District staff responds to concerns of development without
permits and works with property owners to remediate the issue. The goal is compliance so that structures and
surrounding property are not damaged by flooding.
National Flood Insurance Program (NFIP) and Community Rating System (CRS)
In 1970, Maricopa County entered into the NFIP Emergency Program, which provides a limited amount of flood
insurance coverage for structures. Flood Prone Area Maps, developed by the United States Geological Survey
(USGS), were used for floodplain management during this time. The USACE was also preparing maps and
delineated portions of major watercourses such as the Salt, Gila, Agua Fria and New Rivers and Skunk and Cave
Creeks after the District entered into the Emergency Program. The District has since updated mapping for most
of these areas, and continued to participate in the NFIP.
In 1990, the County entered into the NFIP’s Community Rating System (CRS) program. This is a program in which
the County agrees to be rated by the federal government on its effectiveness in performing floodplain
management. Citizens within rated communities may be eligible for flood insurance premium reductions based
on the community’s rating. District activities, including structures and the ALERT program, which are performed
on a regional or inter-jurisdictional basis can be used by local communities for credit in their CRS scoring. Maricopa
County is rated in the top one percent in the nation in the CRS program. Maricopa County is a Category B
community (eight or more repetitive loss areas). Through the FEMA accreditation process, the County is now at
Class 4, which gives residents of unincorporated Maricopa County up to a 30 percent discount on their flood
insurance. Annual reports are submitted to FEMA on program results and regular audits are conducted by FEMA.
As a Class 4 Community, Maricopa County is audited by FEMA every three years.
24

Comprehensive Report and Program - 2020
Summary
The Flood Control District of Maricopa County identifies floodplain hazards and prepares delineations for these
watercourses, ponding areas, and alluvial fans. These delineations are submitted to FEMA and then placed on the
Flood Insurance Rate Maps (FIRM). The District enforces activities in delineated floodplains through the
Floodplain Regulations to guide safe development in these areas. Over the 45 plus years the Regulations have
been in place, county and city populations have continued to increase with substantial development occurring in
the floodplains. Property owners can utilize their floodplain property by building safely in accordance with the
Regulations.
The NFIP is aimed at reducing the impact of flooding on private and public structures. This is achieved by providing
affordable insurance for property owners and by encouraging communities to adopt and enforce floodplain
management regulations. These efforts help mitigate the effects of flooding on new and improved structures. If
a community participates in the NFIP then anyone who wishes to purchase flood insurance can obtain a policy,
whether or not they are located in a delineated floodplain. Flood insurance is the best way for property owners
to protect themselves from devastating financial loss. Flood insurance is available to homeowners, renters, condo
owners/renters and commercial owners/renters. District submittal of delineations to FEMA with the placement
on FIRMs triggers an alert to lenders to require flood insurance on structures in the floodplain if federally backed
mortgages are sought by property owners at any time a loan is requested on a parcel. Due to the many programs
that the District and County agencies have in place, these property owners can receive discounts on their flood
insurance.
25

Comprehensive Report and Program - 2020
Tables
1 – Major Floods and Past Flooding Damage 1891 to Present
2 – Projects by Group from the 1963 Program Report
3 – Flood Control District Dams and Flood Retarding Structures
4 – Flood Control District Levees
5 – FCD Emergency Action Plans (EAP) and Flood Response Plans (FRP)
6 – FCD Completed Capital Projects Through Fiscal Year 2019
7 – Acronyms Used In This Report
Exhibits
Map A Rain Gage Location
Map B Floodplain Delineations
Map C Regulatory Floodplains, Alluvial Fans and Repetitive Loss Areas
Map D Area Drainage Master Studies
Map E Future Delineation Studies
Map F1 Completed Capital Projects, through Fiscal Year 2019 (West of I-17)
Map F2 Completed Capital Projects, through Fiscal Year 2019 (East of I-17)
Map G Capital Improvement Project Areas, Fiscal Year 2021-2024
26

Comprehensive Report and Program - 2020
TABLES
27

Comprehensive Report and Program - 2020
Table 1 - Major Floods and Past Flooding Damage 1891 to Present
Date Remarks
February 18-26, 1891 First record of major flood in Phoenix area. Salt River estimated to have a peak flow of
300,000 cubic feet per second.
August 21, 1921 ~ 4,000 acres flooded including the state capital. Damages estimated at $240,000.
July and August, Severe flood damage to homes, highways, railroads, agricultural infrastructure and crops
1951 in and surrounding the towns of Litchfield Park, Goodyear and Avondale. The Luke Air
Force Base, Goodyear Aircraft Plant and the Litchfield Naval Air Facility were all under
water. Damages estimated in excess of $3,000,000.
August 19-20, 1954 Flooding from heavy rains in the Superstition Mountains caused $446,000 in property
damage and $1.4 million in crop damage in what is now Queen Creek, Gilbert and
Chandler.
August 1963 Damages for Phoenix (Maryvale) and Glendale equal $2,900,000.
December 22, 1965 - First large flow through Phoenix since reservoirs were built on the Verde River (1939).
January 2, 1966 Damages equal $10,000,000.
September 5-7, 1970 Eight lives lost. Damages equal $5,800,000.
June 1972 Damages for Phoenix Metro area equals $10,588,000.
March 1978 Salt River had a peak flow of 122,000 cubic feet per second. Damages estimated at
$33,138,000.
December 1979 Salt River has a peak flow of 140,000 cubic feet per second. Damages estimated at
$51,800,000.
February 1980 Salt River has a peak flow of 170,000 cubic feet per second. Damages estimated at
$63,700,000.
September 27 - Flooding is attributed to Tropical Storm Octave off the coast of Baja California. Although
October 3, 1983 Maricopa County was not one of the eight counties in Arizona to be declared a major
disaster, damage was done to residences, agricultural areas and roads.
January 7-8, 1993 Salt River has a peak flow of 124,000 cubic feet per second. Two lives were lost (kayaking
on river) and over 200 families throughout the County were evacuated from their homes
because of flooding.
September 25-26, Flooding from Hurricane Nora results in the breaching of Narrows Dam in La Paz County.
1997 The calculated 24-hour, 100-year rainfall amount in NW Maricopa County was exceeded
at six ALERT measuring sites.
October 21, 2000 Rain described as heavy and destructive fell in western Maricopa County. Centennial
Wash was hit especially hard.
February, 2005 Following several months of above-average rainfall, a series of storms in February caused
many of the major rivers in Maricopa County to carry significant flows. Several houses
and a bridge were damaged due to bank erosion, total damages were estimated at
$6,500,000.
August 2, 2005 One of the heaviest rainfall events of the 2005 season hit the Phoenix area, where almost
three inches of rain fell in many locations in the metropolitan area, which caused roofs to
collapse and streets to flood quickly. Nearly 120 residents of an apartment community in
Phoenix were evacuated after 83 apartment units were damaged by floodwaters.
28

Comprehensive Report and Program - 2020
August 9, 2005 Heavy rains from widespread thunderstorms caused flash flood waters to over-flow
washes from New River east to the Seven Springs area and Camp Creek. Rain gage
networks indicated that up to 4.5 inches of rain falls during the late afternoon and early
evening. Two fatalities occurred during this storm: A pickup truck driver drowned while
attempting to drive across a flooded road, and a seven-year-old girl that was evacuated
from a home along Camp Creek slipped from the grasp of the adult and was swept away
by a flooded wash. Heavy rains during the afternoon flooded highways and roads in
Queen Creek, while in Tonopah many roads were closed in the area due to rapid flooding.
September 3, 2005 Very heavy rainfall across the far northern portion of the Phoenix metropolitan area
resulted in rapid runoff and flooding. The Seven Springs stream gage indicated a sudden
jump of the water level, from zero to 8.5 feet, in only 20 minutes. The Camp Creek ALERT
system gage recorded a total of 3.11 inches of rain, with 2.01 inches in one hour. Bartlett
Road was washed out and impassable, trapping about 400 motorists as they were
attempting to leave Bartlett Lake. In Phoenix, the heaviest rain storm was reported at the
East Fork of Cave Creek at 7th Avenue, with flooding of many streets in north Phoenix.
July 25, 2006 Heavy rains created a sinkhole adjacent to an apartment building in Tempe, forcing
residents to evacuate. Flood control basins in east Mesa were filled to capacity and
pumping was required.
August 21, 2006 Some streets in northern Tempe were flooded, and the right-hand lanes of both
eastbound and westbound U.S. 60 at Rural Road were closed due to heavy rain.
August 24, 2006 A rainstorm dropped two inches of rain in parts of the Northeastern Phoenix and North
Scottsdale. Both bridged and bridgeless crossings on Indian Bend Wash were closed.
Two motorists attempted to drive across the wash on Indian Bend Road in Scottsdale.
They became stranded, prompting a rescue by 40 members of the Scottsdale Fire
Department. Each motorist was fined for the rescue per the state law that prohibits
motorists from driving on a road that is barricaded due to flood hazards.
September 7, 2006 Roads through Indian Bend Wash in Scottsdale were closed due to rainstorm runoff in the
wash.
July 21-22, 2007 A late start of the monsoon brought heavy rain to the County. Sheet flooding in
Queen Creek turned dirt roads to mud and caused a 1/4-mile long, 12-foot wide, 10-foot
deep fissure in the ground through a rural neighbourhood. Several swift water rescues
were performed, including a 2.5-hour rescue operation in Queen Creek to save a motorist
who had driven into a flood retention area.
July 23, 2007 Approximately two inches of rain fell in parts of the Phoenix metropolitan area, especially
in the northern portion, where a mudslide closed a road in Cave Creek. The washes in the
Gila Bend area were full due to the torrential rains in the area.
July 26, 2007 In the area of Indian springs road, just west of Phoenix International Raceway, rain fell in
some areas at comparable magnitudes to the County 100-year and 500-year 1-hour
rainfall.
July 31-August 1, Up to three inches of rain fell in parts of the northern Phoenix metropolitan area. Various
2007 east-west roads in North Scottsdale were closed due to flooded washes and mud flows.
The impoundment pond behind Cave Buttes Dam received floodwater more than 20 feet
deep.
November 30- The combination of copious Pacific moisture associated with the Baja remnants and
December 1, 2007 dynamic triggered within the coastal system resulted in about 30 hours of moderate to
locally heavy rain bands moving east across Central Arizona with the heaviest rain over
the higher terrain of Northeast Maricopa County.
29

Comprehensive Report and Program - 2020
January 27, 2008 A daylong rainstorm soaked the county and dropped up to three inches of rain in the
northeastern mountains. Cave Creek and New River flowed rapidly, with 14 feet of water
held behind Cave Buttes Dam and 23 feet in the impoundment area behind New River
Dam. A dozen roads in Cave Creek, Carefree and North Scottsdale were temporarily
impassable due to flooded wash crossings. The Salt River Project (SRP) released more
than 15,000 cubic feet per second of floodwater over Granite Reef Dam into the Salt River
through the Phoenix metropolitan area.
July 10, 2008 The first major monsoon storm of the season hit with a fury, dropping more rain in a 12-
hour period than during the entire 2007 monsoon season. A cluster of severe
thunderstorms moved across northwest Maricopa County causing strong winds and
dense blowing dust. A second cluster of severe thunderstorms moved into east-central
parts of the county and converged over the Phoenix metropolitan area. The highest
rainfall totals were in the Wickenburg area (one to three inches), and central Phoenix and
northeast Mesa (one to three inches). 0.83 inches was recorded at Phoenix Sky Harbor
International Airport, where the runways were shut down for a short period. Areas of
street flooding occurred. Rising water forced the closure of Interstate 17 near downtown
Phoenix.
July 13, 2008 A surprise, late-afternoon storm hit Tempe hard, where more than two inches of rain fell
in less than two hours. A five-mile section of the U.S. 60 freeway through Tempe was
shut down for three hours due to deep standing water across several lanes and beneath
underpasses. The Arizona Department of Transportation activated pumps to drain the
water.
Jan. 19-21, 2010 A powerful winter storm system, the strongest since 1993, brought heavy precipitation
and caused $4 million in damage. Much of the region received 1 to 5 inches of total
rainfall over three days, with up to 10 inches recorded by District gages in the mountains
on the northeastern edge of Maricopa County. Depending on the location, the storm was
a 25- to 100-year event, or having a one percent chance of occurring in a year. All major
rivers, streams and washes have significant storm water flow rates. The District's flood
control structures functioned as designed. Cave Buttes Dam had storm water 62 feet
deep in the impoundment pool behind the dam while New River Dam held back 42 feet.
A state of emergency was declared in the county and state. Some roads closed due to
flooded washes. SRP released water from upstream reservoirs into the Salt River.
July 31, 2012 An intense, slow-moving severe thunderstorm produced heavy rainfall in and around the
Anthem community in north-central Maricopa County. The core of the storm remained
nearly stationary over Anthem for approximately 70 minutes. Rain gages operated by the
Flood Control District and independent weather observers recorded a range of rainfall
amounts between 1.38 and 5.01 inches in a 90-minute period, with the highest amount
verified by the National Weather Service Phoenix office. The one-hour rainfall in this
storm exceeds the Flood Control District's highest recorded one-hour total of 3.58 inches
at Vulture Mine Road near Wickenburg on July 21, 1986. Storm water runoff damaged
several homes in Anthem, with up to three feet of flood water inside some of the
structures.
August 12, 2014 A cluster of thunderstorms batters the South Mountain region of Phoenix, causing
flooded roads, damage to agriculture, and flooded residences and businesses. Rain gages
measure intensities in the 500-900 year range for the 2-hour storm duration.
30

Comprehensive Report and Program - 2020
August 19, 2014 Tropically-enhanced rain falls across northern Maricopa County causing very high
discharges on New River, Skunk Creek and Cave Creek. Several home and businesses are
damaged. Rain gages measure up to 500-year return periods. The discharge return
period on New River is estimated at 320 years. Floodwaters broke over the west bank of
Skunk Creek and inundated portions of I-17.
September 8, 2014 The most devastating storm to hit urban Phoenix since June 1972. Tropical moisture
began to fall as rain in the early morning, and by morning rush hour many Valley cities
were crippled. In a six-hour period some areas of the SE Valley received over 5 inches of
rain – a 1,000 year return period. Flooded I-10 was closed for several hours. Homes in
Mesa were flooded by an over-taxed system of flood basins on the north side of US 60.
September 27, 2014 This final major storm of Monsoon 2014 affected east valley cities and NE Maricopa
County with rainfall return periods up to 50 years. The East Maricopa Floodway carried a
discharge peak of nearly 3,000 cfs.
July 18, 2015 Many severe rain events occurred on this day as a result of moisture from Hurricane
Delores spinning off the coast of Baja. Notable for Maricopa County was a storm that
materialized to the southeast of the Town of Wickenburg and moved slowly to the
northwest over a period of two hours. Most rain gages in and around Wickenburg
received between 2 and 4 inches of rain in that two hours. The highest measured
amount was 4.88 inches in 90 minutes. Many area stream gages recorded peaks-of-
record; most have records back to 1996. The three District flood control dams in the area
all experienced record impoundments of more than 75% of spillway capacity.
October 1-3, 2018 A surge of tropical moisture followed by the remnants of Hurricane Rosa led to
widespread rainfall across south-central Arizona during a three day period ending on
October 3, 2018. Maricopa County rain gauges measured storms totals anywhere from 1
inch - 4.5 inches. Rain from this event ultimately led to areas of flash flooding in Gila
Bend, the central Phoenix Valley, portions of Scottsdale, and Fountain Hills. Six
monitored flood control dams experienced record impoundments.
September 23, 2019 A powerful late-season transition event aided by tropical moisture from the remnants of
Hurricane Lorena led to widespread rainfall across south-central Arizona during a five day
period beginning September 23 and ending on September 27, 2019. Maricopa County
rain gages measured event totals anywhere from 0 inches - 4.5 inches. Residents in
Mesa, Apache Junction, Fountain Hills, Buckeye, Tonopah and several other communities
experienced significant flash flooding due to heavy rain from this event.
31

Comprehensive Report and Program - 2020
All of the suggested solutions for eliminating or minimizing flood control problems from the 1963 Program Report
were reviewed and divided into four groups – projects for immediate construction, two groups subject to available
funds, and projects deferred as not feasible. Most of the projects in Group one were completed with some being
combined and being renamed. Today, the current recommended projects are in two tiers.
Table 2 - Projects by Group from the 1963 Program Report – Groups I, II, III, IV
Group No. I - Projects Recommended for Immediate Construction
COSTS Annual Annual Benefit-
Drainage Benefits Costs Cost Ratio Remarks
Location Job Description
Area FCD Other Total
Gillespie Dam to 107th Approved by U.S. Army
1 Channel Clearing 250,000 1,000,000 1,250,000 141,600 80,800 1.75 to 1.00
Ave. Corps of Engineers
Approved by U.S. Army
27 Lower Indian Bend Floodway Channel 1,770,000 7,250,000 9,020,000 530,000 348,000 1.52 to 1.00
Corps of Engineers
Agua Fria, New River, and
19-23 Channel Clearing 250,000 1,000,000 1,250,000 Deer Valley Group
Skunk Cr.
Arizona Canal-Cave Cr. Divert flood water
22 944,000 7,060,000 8,004,000 Deer Valley Group
To Skunk Cr. North of Canal
25 Dreamy Draw Earth Dam 150,000 300,000 450,000 Deer Valley Group
North Mt.-Arizona Canal,
22 Construct Channel 1,400,000 1,926,000 3,326,000 Deer Valley Group
20th St. to 23rd Avenue
New River NW of
22 Earth Dam 2,770,000 2,002,000 4,772,000 Deer Valley Group
Glendale
22 NW of Adobe Earth Dam 832,000 2,301,000 3,133,000 Deer Valley Group
22 Lower Cave Cr. Dam Site Earth Dam 871,000 5,824,000 6,695,000 Deer Valley Group
22 Union Hills Diversion Lined Channel 500,000 1,500,000 2,000,000 Deer Valley Group
22 64th St. to New River Total Deer Valley 7,717,000 21,913,000 29,630,000 2,232,000 1,296,000 1.72 to 1.00
Moved to Group 1 (1963
22 Maryvale-Glendale Drain Lined Channel 320,000 1,462,000 1,782,000 99,000 68,000 1.46 to 1.00
Flood)
22 Glendale-Peoria Drain Lined Channel 426,000 2,552,000 2,978,000 166,000 113,000 1.46 to 1.00 Moved to Group 1
7 Casandro Wash Earth Dam 60,000 0 60,000 4,500 2,500 1.80 to 1.00 FCD Project
Sunset & Sunny Cove
7 Earth Dams 79,000 0 79,000 6,200 3,500 1.77 to 1.00 FCD Project
Washes
32 Buckborn-Mesa Levees & Channels 3,574,000 3,855,000 7,429,000 500,000 281,000 1.78 to 1.00 Under SCS Study
Bender & Sand Tanks Under Study by Corps of
12 Levees 152,000 114,000 266,000 12,500 10,700 1.16 to 1.00
Washes, Gila Bend Engineers
TOTAL - GROUP I 14,348,000 38,146,000 52,494,000 3,691,800 2,203,500 1.68 to 1.00
32

Comprehensive Report and Program - 2020
Recommended Projects Group II - Subject to Availability of Funds
32 Apache Junction-Gilbert Levees & Channels 1,209,000 3,803,000 5,012,000 276,700 198,000 1.40 to 1.00 Under SCS Study
32 Mesa-Chandler-Gilbert Channel 3,000,000 0 3,000,000 259,500 122,400 2.11 to 1.00 Urban Storm Drain
32 Williams-Chandler Levees & Channels 837,000 3,738,000 4,575,000 326,000 189,000 1.73 to 1.00 Under SCS Study
9 Buckeye-Palo Verde Levees & Channels 776,000 2,986,000 3,762,000 175,000 128,000 1.40 to 1.00 Under SCS Study
22 W. Phoenix-Maryvale Channel 337,000 2,205,000 2,542,000 141,000 97,000 1.46 to 1.00 Moved (1963 Rain)
North Phx. Mt.-Old Cross-
22 Channel 966,000 2,360,000 3,326,000 232,000 136,000 1.72 to 1.00 Held Back (Group II)
Cut Canal
TOTAL - GROUP II 7,125,000 15,092,000 22,217,000 1,410,200 870,400 1.62 to 1.00
Recommended Projects Group III - Subject to Availability of Funds
Channel Alignment &
7 Sols Wash 40,000 0 40,000 2,500 2,000 1.25 to 1.00 FCD Project
Protection
Studied by Corps of
7 Powder House Wash Earth Dam 50,000 82,000 132,000 10,000 5,600 1.79 to 1.00
Engineers
Studied by Corps of
7 Cave Creek Town Earth Levee 3,000 12,000 15,000 1,000 840 1.19 to 1.00
Engineers
Maxwell Dam (Flood
31 Earth Dam 650,000 5,050,000 5,700,000 369,000 276,000 1.34 to 1.00 Cost of Flood Control
Control)
Studied by the Corps of
24 Cave Creek Dam (Old) Levee 65,000 91,000 156,000 10,200 8,200 1.24 to 1.00
Engineers
FCD Project-Aid
expected from U.S.
33 Queen Creek Channel 920,000 880,000 1,800,000 90,000 72,000 1.25 to 1.00
Bureau of Indian Affairs
TOTAL - GROUP III 4,407,000 36,376,000 40,783,000 2,282,700 1,664,640 1.37 to 1.00
Group IV - Projects Deferred as Not Feasible at this time
Flying "E" Wash
7 Earth Dam 0 183,000 183,000 4,500 7,200 0.62 to 1.00 Financing a question
Wickenburg
26 Guadalupe Watershed Levees & Channels 519,000 660,000 1,179,000 45,450 60,600 0.75 to 1.00 To be referred to SCS
South Mountain, 40th St. To be studies by Corps of
26 Levees & Channels 2,652,000 6,251,000 8,903,000 253,000 351,000 0.72 to 1.00
to 75th Ave. Engineers
Indian Bend Wash Above To be studied by Corps of
28 Channels 1,217,000 1,701,000 2,918,000 76,000 124,400 0.61 to 1.00
Arizona Canal Engineers
33 Santan Watershed Levees & Channels 895,000 2,678,000 3,573,000 100,000 145,000 0.70 to 1.00 To be studied by SCS
4 Harquahala Valley Levees & Channels 400,000 3,770,000 4,170,000 70,000 171,000 0.41 to 1.00 To be studied by SCS
To be studied by Corps of
6 Box Canyon Earth Dam 652,000 6,948,000 7,600,000 290,000 325,000 0.90 to 1.00
Engineers
7 Sols Wash (Matthie Dam) Earth Dam 500,000 556,000 1,056,000 11,000 43,000 0.26 to 1.00 Studied for recreation
8 Upper New River Earth Dam & Channel 50,000 450,000 500,000 Studied for recreation
33

Comprehensive Report and Program - 2020
Table 3 - Flood Control District Dams & Flood Retarding Structures (FRS)
Dams Region Year O&M Federal Project Status
Completed Agency Sponsor
Adobe Dam N 1982 DISTRICT USACE N/A
Apache Junction FRS and Floodway E 1988 DISTRICT SCS/NRCS N/A
Buckeye FRS No. 1 W 1974 DISTRICT SCS/NRCS Dam Rehab: Design
Phase 2B
Buckeye FRS No. 2 W 1975 DISTRICT SCS/NRCS N/A
Buckeye FRS No. 3 W 1975 DISTRICT SCS/NRCS N/A
Casandro Wash Dam and Outlet NW 1996 Wickenburg N/A N/A
Cave Buttes Dam and Dikes N 1980 DISTRICT USACE Gated Auxiliary
Outlet: Design
Dreamy Draw Dam N 1974 DISTRICT USACE N/A
Guadalupe FRS E 1975 DISTRICT SCS/NRCS Dam Mod:
Investigations Pending
Harquahala FRS and Floodway W 1983 DISTRICT SCS/NRCS N/A
McMicken Dam NW 1956 DISTRICT USACE Dam Rehab: Design
New River Dam NW 1985 DISTRICT USACE N/A
Powerline FRS and Floodway SE 1967 DISTRICT SCS/NRCS Powerline Channel:
Design
Rittenhouse FRS SE 1969 DISTRICT SCS/NRCS Dam Rehab: Pending
NRCS Funding
Saddleback FRS and Diversion Channel W 1982 DISTRICT SCS/NRCS Dam Rehab: Pending
NRCS Funding
Signal Butte FRS and Floodway E 1987 DISTRICT SCS/NRCS N/A
Spook Hill FRS and Outlet E 1979 Various SCS/NRCS Rehab Project
Completed 2008
Sunnycove FRS NW 1976 DISTRICT SCS/NRCS N/A
Sunset FRS NW 1976 DISTRICT SCS/NRCS N/A
Vineyard FRS SE 1968 DISTRICT SCS/NRCS Dam Rehab: Design
White Tanks FRS No. 3 NW 1954 DISTRICT SCS/NRCS Rehab Project
Completed 2011
White Tanks FRS No. 4 W 1953 DISTRICT SCS/NRCS Rehab Construction
Completed 2017
34

Comprehensive Report and Program - 2020
Table 4 - Flood Control District Levees
Year Supervisor
Name Built By Project Status
Completed District
SCS Levee 1
1 East Maricopa Floodway Left Levee (FEMA #21) 1985
(NRCS) Recertification 2021
Pipes rehabilitation 1
2 Indian Bend Wash IBW1 USACE 1977
completed 2019
Pipes rehabilitation 1
3 Indian Bend Wash IBW3 USACE 1978
completed 2019
Pipes Inspection 1
4 Salt River North Levee (FEMA #33) ADOT 1989
planned 2021
Pipes Inspection 1
5 Salt River South Levee (FEMA #33) ADOT 1989
planned 2021
Pipes Inspection 2
6 Indian Bend Wash IBW2 USACE 1979
planned 2021
Pipes Inspection 2
7 Indian Bend Wash IBW4 USACE 1979
planned 2021
SCS Pipes Inspection 2
8 Pass Mountain Diversion Channel Levee (FEMA #291) 1984
(NRCS) planned 2020
Scatter Wash Right Levee (North) (FEMA Pipes Inspection 3
9 ADOT 1991
#1901064146) planned 2020
Scatter Wash Left Levee (South) (FEMA Pipes Inspection 3
10 ADOT 1991
#1901064147) planned 2020
Skunk Creek I-17 Right Levee (SK1) (FEMA Levee 3
11 USACE 1983
#3805020027) Recertification 2020
Skunk Creek I-17 Left Levee (SK2) (FEMA Levee 3
12 USACE 1983
#3805020026) Recertification 2020
Pipes Inspection 4
13 Camelback Ranch Levee North (FEMA #3) FCD 1998
planned 2020
Pipes Inspection 4
14 Camelback Ranch Levee South (FEMA #11) FCD 1998
planned 2020
Pipes rehabilitation 4
15 New River NR1 (FEMA #30) USACE 1989
completed 2019
Pipes rehabilitation 4
16 New River NR/91st Ave (FEMA #30) USACE 1989
completed 2019
Pipes Inspection 4 & 5
17 Agua Fria River Reach 1A East (FEMA #8) FCD 1988
planned 2021
FCD & Pipes Inspection 4 & 5
18 Agua Fria River Reach 1A West (FEMA #18) 1989
USACE planned 2021
Pipes Inspection 4 & 5
19 Agua Fria River Reach 1B & 2 East (FEMA #8) FCD 1988
planned 2021
FCD & Pipes Inspection 4 & 5
20 Agua Fria River Reach 1B & 2 West (FEMA #18) 1989
USACE planned 2021
Pipes Inspection 4 & 5
21 Agua Fria River Reach 3 East (FEMA #8) FCD 1988
planned 2021
35

Comprehensive Report and Program - 2020
FCD & Pipes Inspection 4 & 5
22 Agua Fria River Reach 3 West (FEMA #18) 1989
USACE planned 2021
FCD & Pipes Inspection 4 & 5
23 Agua Fria River Reach 5 (FEMA #18) 1989
USACE planned 2021
Pipes Inspection 5
24 Agua Fria River Reach 6 (FEMA #16) USACE 1989
planned 2021
SCS 5
25 Centennial Wash Levee 1985 No projects planned
(NRCS)
Pipes Inspection 5
26 Tres Rios North Levee (TRNL) USACE 2012
planned 2021
36

Comprehensive Report and Program - 2020
Table 5 – FCD Emergency Action Plans (EAP) and Flood Response Plans (FRP)
Name Type & Last Updated Plan
1 Adobe Dam 2019 EAP
Buckeye Structures (includes Buckeye FRSs No. 1, 2 and 3 and Buckeye 2018 EAP
2
Floodway No. 2)
Buckhorn-Mesa Structures (includes Spook Hill, Signal Butte and Apache 2016 EAP
3
Junction FRSs)
4 Cave Buttes Dam 2016 EAP
5 Dreamy Draw Dam 2017 EAP
6 Guadalupe FRS 2017 EAP
7 Harquahala and Saddleback FRSs 2017 EAP
8 McMicken Dam 2018 EAP
9 New River Dam 2016 EAP
10 Powerline, Vineyard Road and Rittenhouse FRS 2015 EAP
11 White Tanks FRS No. 3 2018 EAP
12 White Tanks FRS No. 4 2014 EAP
Wickenburg Structures (includes Sunset and Sunnycove FRSs and 2017 EAP
13
Casandro Wash Dam)
14 Agua Fria River Reach 1A East (FEMA #8) Short – December 2019 EAP
15 Agua Fria River Reach 1A West (FEMA #18) Short – December 2019 EAP
16 Agua Fria River Reach 1B and 2 East (FEMA #8) Short – December 2019 EAP
17 Agua Fria River Reach 1B and 2 West (FEMA #18) Short – December 2019 EAP
18 Agua Fria River Reach 3 East (FEMA #8) Short – December 2019 EAP
19 Agua Fria River Reach 3 West (FEMA #18) Short – December 2019 EAP
20 Agua Fria River Reach 5 (FEMA #18) Short – December 2019 EAP
21 Agua Fria River Reach 6 (FEMA #16) Short – December 2019 EAP
22 Camelback Ranch Levee North (FEMA #3) Short – January 2020 EAP
23 Camelback Ranch Levee South (FEMA #11) Full – January 2015 EAP
24 Centennial Wash Levee Short – January 2020 EAP
25 East Maricopa Floodway Left Levee (FEMA #21) None - planned 2021 EAP
26 Indian Bend Wash IBW1 Short – December 2019 EAP
27 Indian Bend Wash IBW2 Short – December 2019 EAP
28 Indian Bend Wash IBW3 Short – December 2019 EAP
29 Indian Bend Wash IBW4 Short – December 2019 EAP
30 New River NR1 (FEMA #30) Full – June 2019 EAP
31 New River NR/91st Ave (FEMA #30) Full – June 2019 EAP
32 Pass Mountain Diversion Channel Levee (FEMA #291) Full – January 2015 EAP
Full – June 2020 EAP
33 Salt River North Levee (FEMA #33)
(in progress)
Full – June 2020 EAP
34 Salt River South Levee (FEMA #33)
(in progress)
35 Skunk Creek I-17 Right Levee (SK1) (FEMA #3805020027) Full – December 2019 EAP
37

Comprehensive Report and Program - 2020
36 Skunk Creek I-17 Right Levee (SK2) (FEMA #3805020026) Full – December 2019 EAP
37 Scatter Wash Right Levee (North) (FEMA #1901064146) Short – December 2019 EAP
38 Scatter Wash Left Levee (South) (FEMA #1901064147) Short – December 2019 EAP
39 Tres Rios North Levee (TRNL) Full – October 2017 EAP
40 Aguila/Upper Centennial Wash FRP 2015 FRP
41 Wickenburg/Upper Hassayampa River FRP 2009 FRP
42 Peoria FRP 2013 FRP
43 New River/Skunk Creek FRP 2009 FRP
44 Cave Creek FRP 2018 FRP
2004 (currently being FRP
45 Scottsdale FRP
updated)
46 ACDC/T-bird Paseo Park FRP 2015 FRP
47 Fountain Hills FRP 2002 FRP
48 Gilbert FRP 2019 FRP
49 South Phoenix/Laveen FRP 2016 FRP
50 Bullard Wash FRP 2013 FRP
NOTE: Short: A Short version EAP is four pages long, has best available maps and no levee failure modeling.
Full: A Full version EAP has levee failure modeling and detailed failure inundation maps.
38

Comprehensive Report and Program - 2020
Table 6 – FCD Completed Capital Projects Through Fiscal Year 2019
Project Map Location Year
ID
9th Ave. Storm Drain (Peoria Ave. to
1
ACDC) 48 9th Ave., Peoria Ave. to ACDC 2008
2 10th St. Wash Detention Basin No. 1 49 12th St. and Peoria Ave. 1996
3 10th St. Wash Detention Basin No. 2 49 11th St. and Alice Ave. 1997
10th St. Wash Improvements (Alice 10th St., Alice Ave to ACDC at Griswold Rd.
4
to ACDC) 50 alignment 2008
23rd Ave. and Roeser Rd. Storm NE corner of 23rd Ave. and Roeser Rd.; outlets
5
Drain and Basin 108 along Roeser Rd. and Broadway Rd. 2011
6 24th Ave. and Camelback Rd. Basin 53 24th Ave. and Camelback Rd. 2008
Verde Ln. alignment; 26th Dr. to I-17 Frontage
7
26th Ave. and Verde Ln. Basin 52 Rd. 2007
27th Ave. and South Mountain Ave.
8
Basin & Storm Drain 125 27th Ave. and South Mountain Ave. 2017
35th Ave. and Dobbins Rd. Basin and
9
Storm Drain 56 35th Ave. and Dobbins Rd. 2002
10 43rd Ave. and Baseline Rd. Basin 118 NE corner of 43rd Ave. and Baseline Road 2014
43rd Ave. and Southern Ave.
11
Detention Basin 54 43rd Ave. and Southern Ave. 2005
12 43rd Ave. Storm Drain 54 43rd Ave., Broadway Rd. to Baseline Rd. 2000
13 48th St. Drain 63 San Francisco Canal, 48th St. to University Dr. 1981
14 48th St. Storm Drain 65 48th St., Baseline Rd. to 48th St. Drain 1988
51st Ave. Storm Drain (Bell Rd. to
15
Thunderbird Rd.) 24 51st Ave., Bell Rd. to Thunderbird Rd. 1991
59th Ave. Storm Drain (Bell Rd. to
16
ACDC) 24 59th Ave., Bell Rd. to ACDC 1991
67th Ave. Storm Drain (Bell Rd. to
17
ACDC) 24 67th Ave., Bell Rd. to ACDC 1990
67th Ave. Storm Drain (Olive Ave. to
18
ACDC) 34 67th Ave., Olive Ave. to ACDC 2009
75th Ave. Storm Drain & DRCC Area bounded by 64th Ave. and 71st Ave. from
19
Phase 1 111 south of Van Buren Ave. to Southern Ave. 2011
83rd Ave. and Pinnacle Peak Rd. Area bounded by Calley Lejos (N), Willisams Rd.
20
Drainage Improvements 21 (S), 91st Ave. (W), 83rd Ave. (E) 2008
83rd Ave. Grade Control Structure
21
(Skunk Creek) 25 83rd Ave. and Skunk Creek 2003
91st Ave., Bell Rd. to Greenway Rd.; Greenway
22
91st Ave. and Bell Rd. Drainage 24 Rd., 91st Ave. to New River 1991
115th Avenue/Union Hills Drive
23
Drainage Improvements 126 115th Ave. & Union Hills Dr. 2018
Skunk Creek at Deer Valley Rd. alignment and
24
Adobe Dam 29 39th Ave. alignment 1982
25 Adobe St. Structures over EMF 90 Adobe St. 1/2 mi. east of Greenfield Rd. 1990
39

Comprehensive Report and Program - 2020
I-10, Elliot Rd. to 1/4 mi. south of Warner Rd.; I-
26
ADOT Pit and Diversion Channel 72 10 and 1/4 mi. south of Warner Rd. 1987
Agua Fria River, Camelback Rd. to 1/4 mi. south
27
Agua Fria Channelization 28 of Lower Buckeye Rd. 1988
McLellan Rd. alignment, Tempe Canal at Alma
28
Alma School Drain 75 School Rd. to the Salt River 1969
29 Apache Junction FRS and Floodway 86 Lost Dutchman Blvd. and Idaho Rd. 1988
30 Arizona Canal Diversion Channel 47 Arizona Canal, 37th Street to New River 1994
Ashbrook Wash Channelization Ashbrook Wash between Bayfield Drive and Del
31
Improvements 124 Cambre Avenue 2017
32 Avondale Landfill Excavation 28 Dysart Rd. and Buckeye Rd. 1986
33 Baseline Rd. Storm Drain 55 Baseline Rd., 7th Ave. to 43rd Ave. 2002
Beardsley Rd. Drainage System (7th
34
Ave. to 23rd Ave.) 32 Beardsley Rd., 7th Ave. to 23rd Ave. 1995
Bethany Home Outfall Channel
35
(Phase I) 37 Bethany Home Rd., SR-101L to New River 2000
Bethany Home Outfall Channel Bethany Home Rd., SR-101L to 83rd Ave.;
36
(Phases IIA, IIB and IIC) 38 Grand Canal, Bethany Home Rd. to 67th Ave. 2008
Broadway Rd. Collector Channel Approximately 1/2 mi. east of Higley Rd.,
37
(Broadway Rd. to EMF) 88 Broadway Rd south for 1/3 mi. to EMF 1998
38 Buckeye FRS No. 1 7 I-10, 331st Ave. to 257th Ave. 1975
39 Buckeye FRS No. 2 8 I-10, 254th Ave. to 237th Ave. 1975
40 Buckeye FRS No. 3 9 I-10, 235th Ave. to 215th Ave. 1975
Bullard Wash, Lower Buckeye Rd. alignment to
41
Bullard Wash (Phase 1) 19 Gila River 2001
42 Bulldog Floodway 84 Apache Junction FRS to Signal Butte FRS 1988
Cactus Rd., Scottsdale Rd. to 64th St.; 68th St.,
43
Cactus Rd. Flood Control System 60 Cactus Rd. to Mescal Park 1991
Cactus Rd. Storm Drain (67th Ave. to Cactus Rd., 67th Ave. to Agua Fria Freeway (SR-
44
SR-101L) 33 101L) 1998
45 Camelback Ranch Levee 28 Agua Fria River and Camelback Rd. 1999
Camelback Rd., 64th St. to 68th St; Lafayette
46
Camelback Side Drain Extension 67 Blvd., 64th St. to 68th St. 1986
West Camelback Road from 59th Ave. to 75th
47
Camelback Road Storm Drain 107 Ave. 2012
Area bounded by Sundance Tr. / Tom Darl. Dr.
48
Carefree Town Center Drainage 103 (NW), Bloody Bas. Rd. / Tranquil Tr. (SE) 2002
North of US-60, between Mariposa Dr.
49
Casandro Wash Dam 1 alignment and Los Altos Dr. alignment 1996
Jackson St., Navajo St. to Mohave St.; Mohave
50
Casandro Wash Outlet 1 St., Jackson St. to Casandro Wash 1996
16th St. alignment and Happy Valley Rd.
51
Cave Buttes Dam 42 alignment 1980
18th St. alignment and Happy Valley Rd.
52
Cave Buttes Dam Dike No. 1 42 alignment 1980
40

Comprehensive Report and Program - 2020
32nd St. alignment , 1/2 mi. north of Happy
53
Cave Buttes Dam Dike No. 2 42 Valley Rd. alignment 1980
54 Cave Buttes Dam Dike No. 3 42 9th St. alignment and Dixileta Dr. alignment 1980
55 Cave Creek Channelization 46 Deer Valley Rd. to Arizona Canal 1991
56 Cave Creek Dam 41 16th St. alignment and Jomax Rd. alignment 1923
57 Centennial Levee 4 South of I-10, T2N/R9W, T2N/R10W 1985
Central Arizona Project Detention Approximately Sossaman Rd. alignment and
58
Basin No. 1 91 approximately Mclellan Rd. alignment 2001
Central Arizona Project Detention
59
Basin No. 2 91 93rd St. and University Dr. 2001
Central Arizona Project Detention
60
Basin No. 3 91 Approximately 96th St. and University Dr. 2001
Central Arizona Project Detention
61
Basin No. 4 91 Crismon Rd. and Apache Tr. 2001
Central Arizona Project Detention Northeast corner of Cheshire St. and Southern
62
Basin No. 5 91 Ave. 2001
Central Chandler Area Drainage Area bounded by Ray Rd. (N), Pecos Rd. (S), SR-
63
System 78 101L (W), Arizona Ave. (E ) 2005
City of Phoenix Dam No. 7 Phoenix North Mountain Preserve,
64
Rehabilitation 45 approximately 2nd St. and Aster Dr. 2009
Cloud Road and Sossaman Road SE corner of Cloud Rd. and Sossamna Rd.;
65
Basin and Outlet 109 outlets along Sossman Rd. to Sonoqui Wash 2011
Between Camelback Rd. and Missouri Ave.,
66
Colter Channel 59 Litchfield Rd. to Agua Fria River 1995
Doubletree Ranch Rd., Tatum Blvd to Indian
67
Doubletree Ranch Road System 59 Bend Wash at 58th St. alignment 2004
Area bounded by Fillmore St. (N), Buckeye Rd.
68
Downtwon Phoenix Drainage System 123 (S), 19th Ave. (W), & Central Ave. (E ) 2015
69 Dreamy Draw Dam 57 SR-51 and Northern Ave. 1973
Between Olive Ave. and Glendale Ave., Reems
70
Dysart Drain 17 Rd.to Agua Fria River 1996
Between Val Vista Dr. and Sossaman Rd.,
71
East Maricopa Floodway 90 Brown Rd. to GRIC to the Gila River 1989
El Mirage Rd., from Deer Valley Rd. to a point 1
72
El Mirage Drain 10 1/4 mi. south, to Agua Fria River 1990
Approx. Elliot Rd., approx. Signal Butte Rd. to
73
Elliot Rd. Basin and Channel 95 SR-202L; Crismon Rd. 0.5 mi. north 2007
Ellsworth Rd. Channel at Phoenix- North and East boundaries of Phoenix-Mesa
74
Mesa Gateway Airport 99 Gateway Airport 2008
Area bounded by 4th St. (Avondale) / Lower
75
Elm Ln. Drainage Mitigation 104 Buckeye Rd. / MC-85 2010
Gila / Salt River Clearing (Gillespie
76
Dam to 91st Ave.)* NA Gila / Salt River, Gillespie Dam to 107th Ave. 1985
Rural Rd., 1/2 mi. south of Guadalupe Rd. to
77
Gila Drain Storm Drain 73 1/2 mi. south of Warner Rd. (Hanger Park) 1988
78 Gilbert Crossroads Park Basin 94 Greenfield Rd. and Ray Rd. 1992
79 Golden Eagle Park Dam Modifications 80 Golden Eagle Blvd. and Palisades Blvd. 2002
41

Comprehensive Report and Program - 2020
Greenway Parkway Channel (9th St.
80
to Cave Creek Rd.) 44 Greenway Parkway, 9th St. to Cave Creek Rd. 2002
Guadalupe Rd., Sossaman Rd. to the EMF at
81
Guadalupe Box and Channel 93 Power Rd. 1989
Guadalupe Drainage Improvement
82
Project 70 Town of Guadalupe (Various Basins) 2003
West side of I-10, between Guadalupe Rd. and
83
Guadalupe FRS 71 Baseline Rd. 1975
84 Harquahala Floodway 6 I-10, T2N/R9W, T3N/R9W, T3N/R10W 1982
85 Harquahala FRS 6 I-10, T2N/R9W, T3N/R9W, T3N/R10W 1982
Hawes Rd. Channel (Emelita Ave. to Hawes Rd., Apache Tr. (Main St.) To Emelita
86
Main St.) 89 Ave. (1/2 mi. north of Southern Ave.) 2004
Hermosa Vista Dr. / Hawes Rd. Area bounded by McDowell Rd. (N), Hermosa
87
Storm Drain and Basin 82 Vista Dr. (S), Spook Hill FRS (W), 90th St. (E) 2009
Holly Acres Levee and Bank Gila River North Bank, El Mirage Rd. to 113th
88
Stabilization 40 Ave. 1984
Between Hayden Rd. and Scottsdale Rd., Indian
89
Indian Bend Wash 67 Bend Rd. to Salt River at SR-202L 1985
Indian School Rd. Drain (107th Ave.
90
to Agua Fria) 39 Indian School Rd., 107th Ave. to Agua Fria River 1989
Lafayette Blvd. from Arcadia Dr.to 44th St., and
91
Lafayette Interceptor Drain & Outlet 117 north from Lafayette Blvd. to Colter St. 2014
Area from 43rd Avenue to the Salt River
92
Laveen Area Conveyance Channel 114 between Southern Avenue and Baseline Road 2009
West of Cotton Ln., extending 4-1/2 miles from
93
Loop 303 Outfall Channel 121 approx. Van Buren St. south to the Gila River 2015
94 Lower El Mirage Wash Basin 119 SW corner of El Mirage Road and Cactus Road. 2014
Maryvale Stadium West Inlet Grand Canal, between Indian School Rd. and
95
Channel 51 Osborn Rd., 57th Ave. to 51st Ave. 2001
McDowell Rd., Hawes Rd. to Sossaman Rd.
96
McDowell Rd. Storm Drain and Basin 81 alignment 2010
Area bounded by Grand Ave. (N), Peoria Ave.
97
McMicken Dam 10 (S), 165th Ave. (E), 199th Ave. (W) 1956
Extends 5.5 mi. northeast of northeast end of
98
McMicken Dam Outlet Channel 10 McMicken Dam 1956
New River Channelization (Bethany
99
Home Rd. to Skunk Creek) 26 New River, Bethany Home Rd. to Olive Ave. 1996
New River, Grand Ave. to Skunk Creek,
100 New River Improvements (Grand including Paradise Shores (1/2 mile south of
Ave. to Skunk Creek) 26 Bell Rd.) 2009
Alignment of 79th Ave. and approximately
101
New River Dam 20 Pinnacle Vista Rd. 1985
102 New River Dam Dike No. 1 20 Lake Pleasant Rd. and Dixileta Dr. Alignment 1985
Northern and Orangewood Storm Between Butler Dr. and Glendale Ave., 63rd
103
Drain 36 Ave. to Agua Fria River 2001
104 Northern Ave. Bridge over New River 26 Northern Ave. and New River 1992
Northern Ave. Storm Drain (47th
105
Ave. to 63rd Ave.) 105 Northern Ave., 47th Ave. to 63rd Ave. 2011
42

Comprehensive Report and Program - 2020
North side of new Northern Parkway alignment
106
Northern Parkway Channel 120 from SR-303L to Dysart Rd. 2014
Oak St. Storm Drain (58th St. to
107
Indian Bend Wash) 69 Oak Street, 58th St. to Indian Bend Wash 2000
108 Old Cross Cut Canal 64 48th St., Arizona Canal to McDowell Rd. 1991
Extension from the Arizona Canal to Indian
109
Old Cross Cut Canal Extension 64 School Rd. 2011
Olive Ave. Storm Drain (51st Ave. to
110
91st Ave.) 35 Olive Ave., 51st Ave. to 91st Ave. 1995
Between Osborn Rd. and Thomas Rd., 60th St.
111
Osborn Rd. Storm Drain 68 to Ind. Bend Wash at 76th St. and Earll Dr. 2001
Paradise Valley Detention Basin No. Paradise Valley Community College
112
4 43 (Component of Upper E. Fork Cave Creek) 1991
McKellips Rd., Crismon Rd. to Signal Butte Rd.,
113
Pass Mountain Diversion Channel 85 south to behind Signal Butte FRS 1987
North bank of Gila River, between Perryville Rd.
114
Perryville Bank Stabilization 14 and Cotton Ln. 1984
Pinnacle Peak Channel & Basin & Pinnacle Peak Rd. - 89th to 99th Ave.; Rose
115
Rose Garden Ln. Basin 110 Garden Ln. from Lake Pleasant Rd. to Agua Fria 2012
Powerline FRS, southwest to Ray Rd. alignment
116
Powerline Floodway 96 at GM, to EMF at Sossaman Rd. 1968
117 Powerline FRS 96 US-60 and Guadalupe Rd. alignment 1967
SR-101L (Price), Salt River to 1/2 mi. south of
118
Price Road Drain 74 Guadalupe Rd. (Carriage Lane Park) 1993
Queen Creek Channel (Hawes to
119
Power) 101 Queen Creek, Hawes Rd. to Power Rd. 2006
Queen Creek Channel (Recker to
120
Higley) 101 Queen Creek, Recker Rd. to Higley Rd. 2009
121 Queen Creek Road Basin 79 McQueen Rd. and Queen Creek Rd. 2009
122 Reems Road Channel and Basin 16 Reems Rd. and Olive Ave. 2009
123 Rittenhouse Basin 100 NW corner of Rittenhouse Rd. and Power Rd. 2010
124 Rittenhouse FRS 98 US-60, Queen Creek Rd. alignment 1969
Rittenhouse Rd., Queen Creek Rd. to the EMF
125
Rittenhouse Road Channel 100 at Pecos Rd. 1997
Roosevelt Irrigation District Canal
126
Overchute 27 Litchfield Rd. and RID Canal 1998
127 Saddleback Diversion Channel 5 South of I-10, T2N/R8W, T1N/R8W 1981
128 Saddleback FRS 5 South of I-10, T2N/R8W, T1N/R8W 1981
Salt River Channel (McClintock Dr. to North bank of Salt River, McClintock Dr. to Price
129
Price Rd.) 66 Rd. 1998
Salt River Channel (Price Rd. to
130
McKellips Rd.) 66 Salt River, Price Rd. to McKellips Rd. 1998
Salt River Channel (SR-143 to
131
McClintock Dr.) 66 Salt River, SR-143 to McClintock Dr. 1991
Salt River Low Flow Ch. (19th Ave. Salt River, 19th Ave. to I-10 at approximately
132
to I-10) (Phx. Rio Salado) 62 30th St. alignment 2002
Scatter Wash Channel and Basin at
133
I-17 30 Scatter Wash at I-17 2010
43

Comprehensive Report and Program - 2020
Scatter Wash Channel (43rd Ave. to
134
35th Ave.) 31 Scatter Wash, 43rd Ave. to 35th Ave. 1995
Scottsdale Rd. Drainage Approximately Scottsdale Rd., Thunderbird Rd.
135
(Thunderbird to Doubletree Ranch) 61 to Doubletree Ranch Rd. 2008
Between McLellan Rd. and Adobe Rd., Signal
136
Signal Butte Floodway 84 Butte FRS to CAP at Ellsworth Rd. 1984
137 Signal Butte FRS 84 Southwest of Signal Butte Rd. and McKellips Rd. 1987
Siphon Draw Drainage Meridian Rd., 1/4 mi. south of Baseline Rd. to
138
Improvements 106 Elliot Rd., basin east of Meridian Rd. 2010
Skunk Creek / ACDC Low Flow Skunk Creek, New River to 75th Ave.; ACDC,
139
Channel 23 73rd Ave. to Skunk Creek 2007
Skunk Creek, approximately Jomax Rd.
140
Skunk Creek Channel and Levee 22 alignment to Central Arizona Project 1983
Skunk Creek Channel Imp. (75th
141
Ave. to 51st Ave.) 22 Skunk Creek, 75th Ave. to 51st Ave. 2000
Skunk Creek Sports Complex Bank
142
Protection 22 Skunk Creek, New River to 75th Ave. 1999
Sonoqui Wash Channelization (Higley Sonoqui Wash, Higley Rd.and Ocotillo Rd. to
143
to Chandler Heights) 102 Chandler Heights Rd. and Sossaman Rd. 2008
Sonoqui Wash Channelization Sonoqui Wash, Chandler Heights Rd. to Riggs
144
(Chandler Heights to Ellsworth) 113 Rd., and east from Hawes Rd. to Ellsworth Rd. 2013
Sonoqui Wash, Empire Road at Ellsworth Rd,
145
Sonoqui Wash Main Branch 113 northwest to Riggs Road at Hawes Road 2017
Sossaman Rd., Southern Ave. to Guadalupe Rd.
146
Sossaman Channel and Basin 92 (Basin at US-60) 1977
Southeast Phoenix Regional
147
Drainage System 76 SR-202L and 48th St. 2002
Southeast Valley Regional Drainage SR-202L to Pecos Rd. 1/2 mi. west of Kyrene
148
System 77 Rd., to I-10, south to the Gila Drain floodway 2002
SR-202L, Power Rd. to 1/4 mi. south of Brown
149
Spook Hill FRS and Floodway 83 Rd.; CAP, SR-202L, north 1 1/2 mi. 1979
SR-202L, Power Rd. to 1/4 mi. south of Brown
150
Spook Hill FRS Rehabilitation 83 Rd.; CAP, SR-202L, north 1 1/2 mi. 2008
Kellis Rd. alignment and Turtleback Ln.
151
Sunnycove Dam 3 alignment 1976
152 Sunset / Sunnycove Pipeline 2 Sunnycove Dam, to a point 1 mi. northeast 1976
South of US-60, between Cucuracha St.
153
Sunset Dam 2 alignment and Whipple Ct. alignment 1976
154 Tatum Wash Detention Basin 58 45th St. and Shea Blvd. 1998
North bank on the Salt & Gila Rivers from 91st
155
Tres Rios Levees 115 Ave. to the Agua Fria River. 2011
156 University Drive Basin 87 64th St. and University Dr. 1992
Two channel branches from 92nd and 96th
157 Upper Camelback Wash Drainage streets from Shea Boulevard to Sweetwater
Improvements 122 Ave. 2015
Area bounded by SR-101L (N), Bell Rd. (S), 9th
158
Upper East Fork Cave Creek 43 St. (W), 32nd St. (E); 4 basins & PVCC 1996
44

Comprehensive Report and Program - 2020
159 Vineyard FRS 97 US-60 and Ray Rd. alignment 1968
Jackrabbit Tr. alignment and Glendale Ave.
160
White Tanks FRS No. 3 12 alignment 1954
White Tanks FRS No. 3 North Inlet Beardsley Canal, Olive Ave. to White Tanks FRS
161
Channel 11 No. 3 2008
White Tanks FRS No. 3 Outfall Jackrabbit Trail (195th Avenue), from McDowell
162
Channel 112 Road to Missouri Avenue. 2013
163 White Tanks FRS No.4 13 Jackrabbit Trail and Van Buren Street. 1954
Wickenburg Downtown Flooding Sol's Wash, from the Highway 93 Interim
164
Hazard Mitigation 116 Bypass Bridge to the Tegner St. Bridge 2009
*Initially cleared; conditions subsequently reversed.
Total Count: 164
45

Comprehensive Report and Program - 2020
Table 7 - Acronyms Used In This Report
Acronym Description
ADMS Area Drainage Master Study
ADMP Area Drainage Master Plan
ADWR Arizona Department of Water Resources
ARS Arizona Revised Statutes
BOD Flood Control District Board of Directors
CAP Central Arizona Project
CIP Capital Improvement Program
CIPPP Capital Improvement Program Prioritization Procedure
CTP Cooperating Technical Partner
District Flood Control District of Maricopa County
EAP Emergency Action Plan
FCAB Flood Control Advisory Board
FCD Flood Control District of Maricopa County
FDS Floodplain Delineation Study
FEMA Federal Emergency Management Agency
FIRM Flood Insurance Rate Map
FPAP Floodprone Properties Assistance Program
FRS Flood Retarding Structure
MSP Meteorological Services Program
NFIP National Flood Insurance Program
NRCS Natural Resources Conservation Service
Report Comprehensive Report and Program
SPAP Small Projects Assistance Program
USACE United States Army Corps of Engineers
46

Comprehensive Report and Program - 2020
EXHIBITS
47