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El Vado Wash Drainage Improvements

Study status:  Letter of Map Revision (LOMR) approved by FEMA. The new mapping will be effective April 21, 2020. Phase 1 improvement plans are in progress.


This project is potentially the first of the drainage infrastructure improvements recommended by the Airport Wash South Basin Management Study (AWBMS). In cooperation with the City of Tucson (COT), Pima County Regional Flood Control District (PCRFCD) is looking at the viability of constructing a culvert beneath Calle Santa Clara north of the New Hope United Methodist Church. The culvert would outlet into a detention basin constructed in the open space adjacent to the church. The basin would outlet via a storm drain to be constructed beneath Calle Sevilla and a weir to a reconstructed, inverted crown Calle Medina.

If funded, this project would be the first phase of drainage improvements within the watershed that will ultimately remap the Federal Emergency Management Agency (FEMA) floodplains within the El Vado Wash Watershed.

For more information contact:
Janice Hughes, PE, Civil Engineer
(520) 724-4600

Scope of Work

The scope of work depends on the cost of the project and the District's ability to fund the project. If funded, the first part of this project will be to submit to FEMA the Hydrologic and Hydraulic Modeling completed with the AWBMS. This revised information will set the design discharges for this and future phases of construction.

The second part of this project is the completion of design plans for the proposed improvements. The AWBMS recommended a culvert at Calle Santa Clara (EV7) to inlet into the detention basin. The Basin will be approximately 6 feet deep outletting to the north as open channel flow along a reconstructed Calle Medina and to the west through a new storm drain beneath Calle Sevilla. Both will take flow to the existing I-19 culvert and through to the Santa Cruz.

The third part of the project will be the construction of the proposed improvements, expected to commence in FY 2020/21.


The Flood Insurance Rate Map (FIRM) for a community depicts the Special Flood Hazard Area (SFHA), the area that has been determined to be subject to a 1 percent or greater chance of flooding in any given year (i.e., 100-year floodplain). The FIRM is used to establish whether flood insurance is required, flood insurance premium rates, and to help the community with floodplain management.

The Pima County Regional Flood Control District (District) on behalf of the City of Tucson (City) applied for a Letter of Map Revision (LOMR) from the Federal Emergency Management Agency (FEMA) to revise FIRM panels 04019C2288L and 04019C2880L to reflect improved data and modeling techniques. FEMA has agreed to revise the SFHA for the areas surrounding the El Vado Wash effective April 21, 2020. The proposed LOMR will result in:
1) Narrowing the width of the SFHA;
2) removing 8.49 acres of land from the SFHA, and
3) decreasing the water surface elevation of the flooding for those areas that remain in the SFHA.

The map revisions may remove the need for property owners in the area to carry federal flood insurance or reduce the flood insurance rate on their home. Home owners should contact their mortgage holder or insurance company prior to April 21, 2020 to verify the impact of this LOMR. Floodplain revision maps are below:
If you have any questions or concerns about the proposed project or its effect on your property, please contact Janice Hughes, Civil Engineering Manager, with the District at (520) 724-4600, or Elizabeth Leibold, Civil Engineer with the City at (520) 837-4934, Monday through Friday from 8:00 a.m. to 4:30 p.m.

Si necesita ayuda con la traducción, favor de comunicarse con Francisco Ramirez al número (520) 724-4600.
A public meeting discussing this and the other recommended projects from the AWBMS was held at the Desert Diamond Casino on June 25, 2014. Additional mailings and outreach will be forthcoming as the project progresses. 

If you have any questions about the project please contact Janice Hughes, PE, Project Engineer, Pima County RFCD at 724-4600 or
August 23, 2005 - Photos by Eric Griffin