Project Details

Lower El Mirage Wash Basin

Public Meetings

Currently there are no public meetings scheduled for this project.

Past Public Meetings

• 8/9/2012
Project Contact: Mike Duncan
Region: NW
District: 4 - Clint L. Hickman

The Flood Control District of Maricopa County (District), in partnership with the City of El Mirage (City), is conducting a design project for flood control improvements at the existing, roughly graded detention basin of Lower El Mirage Wash near the southwestern corner of El Mirage Road and Cactus Road. The improvements will reduce flooding hazards to properties along Lower El Mirage Wash between the basin and the Agua Fria River, and will help improve the aesthetic character of the basin site. This design project is based on the recommendations of the District’s Lower El Mirage Wash Design Concept Report completed in 2011.

The project design basis is the one-percent annual chance storm (the 100-year storm). The project improvements will include: gentle side slopes, terraced levels within the basin that will provide areas for potential City multi-use recreational opportunities, and an improved culvert under El Mirage Road. The landscaping approach will create a basin that is visually compatible with the surrounding neighborhoods, and will include tree and shrub landscaping and some grass-turf areas. The City has already completed design plans for a box culvert under Cactus Road as part of a separate Cactus Road Improvements project.

In addition to basin improvements, the project will re-delineate (with updated stormwater discharges and new topographic mapping) the floodplain limits of Lower El Mirage Wash from Cactus Road to the Agua Fria River resulting from the basin improvements. The results of this delineation will be sent to the Federal Emergency Management Agency (FEMA) in what is called a Conditional Letter of Map Revision (CLOMR). This is the first step in securing approval from FEMA for revisions to the Flood Insurance Rate Maps (FIRMs). Once the FIRMs are revised, affected property owners typically see changes in their flood insurance rates or requirements.


The construction was completed in March 2014. The City of El Mirage, who owns, operates and maintains the facility, has named it Basin Park.

Available Documents

Document Name Type Size
2013 Notice of Construction PDF 2.60 MB
2013-06 Notice of Construction Detour PDF 344 KB
2013-07 Cactus Road Traffic Advisory PDF 347 KB
2013-07 Notice of 125th Ave Closure PDF 344 KB
2013-08 Traffic Advisory Notice PDF 348 KB
2013-10 October Update PDF 320 KB
2014 Project Completion Announcement PDF 140 KB
Conceptual Landscape Plan PDF 1.4 MB
Headwall Aesthetics PDF 508 KB
Headwall Formliner Patterns PDF 1.60MB
Public Open House Announcement PDF 1.47 MB

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