Council Report

City Council Report
Date: October 26, 2026
To: City Council
Through: Marc Heirshberg, Assistant City Manager
From: Lance Webb, City Engineer
Marc Ahlstrom, Assistant City Engineer
Subject: Pecos Road Basins and Storm Drain Improvements
City Project No. CP1230PRSD
Council District 6
Purpose and Recommendation
The purpose of this report is to request Council’s approval of a resolution authorizing the
City of Mesa to enter into an intergovernmental agreement (IGA) with the Flood Control
District of Maricopa County (FCDMC) for Construction, Construction Management,
Operation, and Maintenance of the Pecos Road Basins and Storm Drain Improvements
project (Refer to Exhibits “A” and Exhibit “B” for the project’s location).
Staff recommends that Council approve the resolution and authorize the City Manager to
execute this IGA on behalf of the City. The IGA will authorize a cost share of expenditures
not to exceed a total of $17,800,000. The City’s responsibility will be fifty percent (50%),
up to $8,900,000, and FCDMC will be responsible for the remaining fifty percent (50%),
up to $8,900,000.
Background
The Pecos Road corridor between Meridian and Ellsworth Roads has a long history of
experiencing damaging floods due to its location, which functions as a regional
concentration point for sheet flow and small wash flooding. The corridor was previously
analyzed with older drainage master studies and identified in the current Queen
Creek/East Mesa Area Drainage Master Study/Plan Update (QC/EM) as an area of
concern.
In 2015, the FCDMC commissioned the development of a concept design to mitigate the
identified flooding through the construction of a series of basins and storm drains
designed to convey the 10-year event, at a minimum. The 2015 design concept report
(DCR) proposed a system that captured flows near the Meridian Road alignment and
ultimately discharged them to the Ellsworth Channel at Ellsworth Road.

Since the development of the 2015 DCR, improvements in the watershed have altered
drainage conditions in the Pecos Road corridor. These include upstream roadways and
developments, primarily along the new State Route 24 (SR24) freeway and Meridian
Road between Ocotillo Road and the SR24 interchange. As part of the QC/EM, the full
watershed model was updated with hydraulic modeling software to better reflect current,
as well as existing flooding conditions. Using this updated modeling, the 2015 DCR
concept design was further developed into three alternatives via the Pecos Road Corridor
Pre-DCR Assessment in spring of 2023.
Discussion
In 2024, the City of Mesa entered into an IGA with the FCDMC for design-phase efforts
to develop and refine the preferred 2023 Pre-DCR assessment design concept into
construction documents for the project.
The purpose of this IGA is to advance the project from design to construction. The City of
Mesa will be the lead, and both agencies will fund the project according to a 50% (City of
Mesa) and 50% (FCDMC) split.
Community Impact – This IGA will allow the City to continue its efforts towards a regional
drainage improvement project that mitigates flooding along the Pecos Road corridor.
These regional drainage improvements will shift runoff from current flow paths, which are
a patchwork of private conveyance facilities and undeveloped parcels, to an engineered
system with capacity to convey the 10-year event, at a minimum. This will increase
roadway access during rain events and expand flood protection for existing
developments.
Alternatives
The City Council could choose not to enter into this IGA. This is not recommended
because of the benefits to the City mentioned above, and the loss of an opportunity to
cost share new City infrastructure with the FCDMC.
Fiscal Impact
The total potential fiscal impact of this IGA is $8,900,000.
This project is funded by Local Streets Sales Tax.
Coordinated With
The Transportation Department concurs with this recommendation.
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