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Alamo Wash Basin Management Study

Study status:  Existing Conditions Analysis

Study/Project Purpose

For more information contact:
Terry Hendricks, Project Manager
(520) 724-4600

The purpose of the Alamo Wash Basin Management Plan is to identify flood hazard areas and drainage problems to develop cost-effective solutions to alleviate or manage flooding in the project area. The plan will improve public safety, provide fiscal responsibility, and provide a balanced multi-objective approach to managing the watersheds, floodplains and resources in the project area. This will allow the Pima County Regional Flood Control District, as well as its partners in the City of Tucson to develop a comprehensive flood control plan.

Project Updates

Project updates are provided below.

Open House

There will be an Open House meeting on April 17, 2019 from 5:30 to 7:00 p.m. at the Alice Vail Middle School, 5350 E. 16th St. For more information click here.

The Alamo Wash Basin Management Plan Existing Conditions Report has been completed.

Project Location

The project area is approximately 9.5 square miles, located within the City of Tucson. The Alamo Wash drains into the Rillito Creek east of Swan Rd. The Alamo Wash Basin Management Study includes the Alamo Wash, Arcadia Wash, Van Buren Wash (street) and Sahuara Wash (street).

Please see the Alamo Wash Basin Management Study Area map for the study boundaries.

Project Description

The Pima County Flood Control District is undertaking this project in partnership with the City of Tucson. The project area includes the urban areas which drain into the Alamo and Arcadia Washes within the City of Tucson, primarily west of Kolb Rd. and east of Swan Rd., between Golf Links Rd. and the Rillito Creek.   FEMA has identified Special Flood Hazard Areas (100-year floodplains) associated with the washes which encompass homes and businesses.  These FEMA 100-year floodplains include areas along Van Buren St. and Sahuara Ave. upstream of the Alamo Wash.  In addition, the project area is subject to access limitations during flooding at street dip section crossings of the washes.

This project will develop an Alamo Wash Basin Management Plan which will identify flood hazard areas and drainage problems, and cost-effective solutions to alleviate or manage flooding to increase public safety in the project area.

Project Elements

Existing Conditions Analyses

The Alamo Wash Basin Management Plan Existing Conditions Report has been completed.

Alternatives Analysis

Alternative analysis will identify flood hazard solutions based on the data gathered and produced under the Existing Conditions Analyses. Structural and non-structural cost effective solutions for mitigating flooding and drainage problems will be developed.

Public Involvement

 Stakeholder meetings will be held throughout the duration of the project. In addition, there will be three public open houses.

Maps

The hydrologic modeling for the Alamo Wash Basin Study was performed with the FLO-2D computer program.  The rainfall to runoff analysis of the 9.6 square mile watershed consisted of analyzing 1 million 15-foot grid elements, 46 bridges and culverts, 26 miles of storm drains, 1,000 drain inlets, and underground culvert junctions.  The FLO-2D flood depths for the 100-year flood*  are show on the maps linked below.  


Clickable index map of the Alamo Wash floodplain.

Future Mapping Efforts- Floodplain Map Revisions

The maps linked above do not replace the Flood Insurance Rate Maps (FIRMs) banks use to determine if homeowners must carry flood insurance.  Further analysis is needed to assess if a map revision is achievable.  Additional notifications will be made as this analysis progresses.  

 * The 100-year flood has a recurrence probability of 1% any given year.  It can occur or be exceeded multiple times over 100 years or may not occur within 100 years.  It is a statistical probability that is not associated with a calendar.

Northern map of Alamo Wash floodplain Middle map of Alamo Wash floodplain Southern map of the Alamo Wash floodplain

Project Schedule

The Alamo Wash Basin Management Study kicked-off in October of 2016 and is slated for completion by May 2019.

Public Involvement

Open  House Meeting (October 23, 2017)

RFCD staff discusses the Alamo Wash study with a resident.The study consultant discusses the Alamo Wash study with residents.The Pima County Regional Flood Control District hosted an open Open House on Monday, October 23, 2017 at 5:30 to 7:00 at the Dodge Middle School, 5831 E. Pima St., to discuss the progress of the project and the next steps. Please see the Open House #2 presentation for more information.

Public Comments from Second Open House are available for review.
The study consultant discusses the Alamo Wash study with residents. The District project manager presents informtion to the audience.


Open  House Meeting (March 22, 2017)

The public watches the Open House PresentationPima County Regional Flood Control District held an Open House on Wednesday, March 22, 2017 at 6:00 pm at the Sky Islands School, 6000 E. 14th St.  Please see the Open House Presentation to view the formal presentation.
Public Comments from First Open House are available for review. Open house participants look at a project map with District staff.




Public Sector Stakeholder Meeting (February 10, 2017)

Photo from stakeholder meeting on 2/10/2017.Pima County Regional Flood Control held a Public Sector Stakeholder Meeting to review the project scope and to solicit input from government stakeholders on February 10, 2017 at the Joel D. Valdez Main Library.   A copy of the meeting Presentation and public comments are available below.
Public Sector Stakeholder Meeting Presentation Photo from stakeholder meeting on 2/10/2017.

Your input and feedback

If you have photos or information on flooding or erosion issues within these watersheds that you would like to share with the District, please feel free to contact us using the contact information above the tabs.