RDR 3 Report - Flood Control District of Maricopa County

4. 47 th Avenue System
The 47 th Avenue Channel and Basin were identified by the Review
Committee as Priority 3 projects. These projects are noted to be of low
importance by the City of Phoenix due to the industrial nature of the
area and the lack of prior flooding reported in this area.
5. Tres Rios System
The Tres Rios Basins were identified by the Review Committee as
Priority 2 projects. The Tres Rios Basins should be constructed
concurrently with the proposed Tres Rios levee. The Tres Rios Basins
would not be needed without the proposed Tres Rios levee in place.
C. Project Funding
The projects identified in this master plan are recommended within the
context of the existing development and environmental conditions of
the study area as of this writing. The Durango ADMP area is
developing at a rapid pace. Basin sites and channel alignments have
been proposed based on perceived availability of those sites based on
recent aerial photographs, field reconnaissance, and development
planning information provided by the Cities and County staff. For this
plan to become a reality, steps must be taken by each of the project
participants to begin acquisition of needed right-of-way and to develop
implementation plans. This section presents funding options to assist
with the timely implementation of the adopted plan.
1. Estimated Costs
The total estimated cost of each of the projects identified in Section V
is summarized in Table 2. The estimated costs are broken down
according to the following:
- Land acquisition cost
- Landscape cost
- Construction cost
- Construction contingency at 15 percent of construction cost.
- Design and construction management cost at 15 percent of
construction cost
- Total estimated cost, and
- Estimated annual maintenance cost.
Major cost items included in the channel cost estimates are excavation,
concrete, utility relocations, maintenance roads, land acquisition, and
landscape. The current FCMDC policy allows landscape cost of up to
$0.92 per square foot for which they will share the expense up to 50%.
This allowed cost is approximately half of the $1.80 per square foot cost
estimated in this study, resulting in the FCDMC paying 1/4 of the total
landscape cost as estimated. Utility relocation costs are computed
separately and included in the table as a lump sum per project. Land
acquisition costs are included only for new facilities and are based on
required right-of-way widths.
Culvert costs are based on the length, number of barrels and size for
each crossing and includes inlet and outlet headwalls.
Detention basin costs include basin excavation, outlet headwall and
drain pipe with manholes, inflow spillway, land acquisition, and
landscape.
A detailed breakdown of the estimated cost for each project is contained
at the end of the report on the page facing the exhibits showing the
project elements and I.D. descriptors.
2. Funding Sources
a. FCDMC CIP Process
The FCDMC participates in the planning, design, and construction of
flood control projects throughout Maricopa County. The FCDMC
follows an annual process of project prioritization to identify projects
for their CIP program. The process of getting a project or projects
funded by the FCDMC begins with a sponsoring agency, such as a City,
submitting a project request to the FCDMC. The FCDMC includes
projects requested by their constituent Cities in the prioritization
process. Factors that are considered favorably in the prioritization are
whether the project has been recommended in an adopted FCDMC
Drainage Master Study, the level of cost participation offered by the
City, and who will provide ongoing maintenance of the facility. Projects
are seldom selected for the CIP budget with no cost sharing. The
FCDMC typically seeks a 50 percent level of cost participation.
b. Project Participants
The development of this master plan has been a cooperative effort
between many agencies and local interests within the study area. The
agencies have been involved throughout the project with an eye towards
developing a plan that will be consistent with the ongoing development
plans within the area and will be accepted by the local interests. The
following agencies have an interest in the area and will benefit from
implementation of the plan:
- City of Phoenix
- Maricopa County Department of Transportation (MCDOT)
- City of Tolleson
- City of Avondale
- Salt River Project (SRP)
- U.S. Army Corps of Engineers (Tres Rios)
- Flood Control District of Maricopa County (FCDMC)
- Multiple Private Developers
Projects where shared benefits may accrue to the above agencies are
identified in Section V, Recommended Plan. It is anticipated that as a
result of the information contained in this Recommended Design Report,
a concept for shared project participation can be agreed upon between
the agencies.
City of Phoenix
The City of Phoenix is expected to share a significant portion of the cost
of the Durango Regional Conveyance System. The City has planned
improvements for a storm drain system in 75 th Avenue which could be
integrated into this overall ADMP. Additionally, the City would be
responsible for partial construction costs based on an agreement to be
developed with the FCDMC.
DIBBLE & ASSOCIATES 46 DURANGO AREA DRAINAGE MASTER PLAN
August 2002
RECOMMENDED DESIGN REPORT