Pima County Logo
  • Increase font size
  • Decrease font size
  • Print
  • RSS

Ruthrauff Basin Management Study

Study status:  Complete

Study/Project Purpose

For more information contact:
Evan Canfield, P.E., CFM
(520) 724-4600

The purpose of the Ruthrauff Basin Management Plan was to develop a comprehensive flood control protection program and to develop drainage alternatives which will improve public safety, provide fiscal responsibility, and provide a balanced multi-objective approach to managing the watersheds, floodplains and resources in the study area.

Project Updates

The Ruthrauff Basin Management Study was completed in 2017.  The Pima County Board of Supervisors adopted the Ruthrauff Basin Management Study (Resolution 2017-FC 3) on October 3, 2017.  The City of Tucson Mayor and Council adopted the Ruthrauff Basin Management Study (Resolution 22833) on October 24, 2017.

Throughout the project updates were provided to stakeholders and the public, which are referenced below.

 

Project Location

The Ruthrauff Basin is located in both the city of Tucson and unincorporated Pima County adjacent to Interstate 10 and the Union Pacific Railroad. The Ruthrauff Basin drains into the Santa Cruz River from the east just upstream with the confluence with the Rillito River.  Please see the Ruthrauff BMP Approximate Project Limits map for the study boundaries.

Project Description

The project area includes several small watersheds which drain north to the Rillito River as well as the Ruthrauff Wash which drains into the Santa Cruz River. The area is subject to frequent and substantial sheet flow and ponding of stormwater as a result of the minimal topographic relief and inadequate drainage structures. Historically, floodflows have ponded on the east side of the Union Pacific Railroad embankment. A lack of adequate drainage from the basin to the Santa Cruz River was highlighted repeatedly as the ultimate source of the problem. Some of the recommendations of the “Ruthrauff Basin Study Volume 1, Volume 2, Volume 3 (CBA, 1983)” have been adopted including a storm drain along Ruthrauff Rd. However, there are still areas mapped as FEMA or local floodplains along the Union Pacific Railroad. Flooding in the area between Prince Rd and Ruthrauff Rd comes from both the Flowing Wells Wash and Ruthrauff basin. Flow overtops the channel and runs along the Railroad to the northwest and combines with flow from the Ruthrauff basin. As part of the widening of Interstate 10, the drainage across the Union Pacific Railroad will be improved, which will provide an outlet for the water that ponds along the railroad during flood events.

This project developed a Ruthrauff Basin Management Plan which identified flood hazard areas and drainage problems, and cost-effective solutions to alleviate or manage flooding in the project area. The plan incorporates all the existing, new and proposed storm drains constructed along the railroad.

Project Elements

Existing Conditions Analysis

  • Existing Conditions Analysis: Review previous studies, and identify areas of drainage and erosion hazards.
  • Two types Local Floodplains have been Mapped: Because much of this area experiences sheet flooding, it is an ideal area for mapping using a grid-based approach, which is a relatively new technology. The grid-based maps show how water flows more accurately than the approach used in the current floodplain maps.
    • Regulatory Floodplains: Regulatory Floodplains are delineated based on the 1% annual chance flood (100-year) and are used for administering the floodplain ordinance, which is the basis for permitting uses in regulatory mapped floodplains.
    • Floodplains of Problem Storms: More frequent floods, such as the 10- or 25-year flood, can create problems such as flooding of yards and roadways. Therefore, this study will map these more frequent flows so that solutions can be developed for them.
  • Revised FEMA Floodplains were created: The new culvert crossing at Flowing Wells Wash reduces flooding on the Flowing Wells Wash and the FEMA Floodplain to the north, which showed water ponding behind the railroad track embankment. Therefore, the project team prepared a new floodplain map of this area approved by FEMA, (FEMA Letter of Map Revision 17-09-0333p-040073 & 17-09-0333p-040076 ; effective March 26, 2018) which reflects this reduced risk.

Alternative Analysis

Alternative Analysis and Recommended Solutions: Alternative analysis for the General Study Area have been identified flood hazard solutions based on the data gathered and produced during the previous elements effort. Develop structural and non-structural alternative solutions for mitigating the floodplain and erosion hazards identified in the existing conditions analysis, including cost effectiveness, and recommend an alternative for each flood hazard.

Public Involvement

Public Involvement: Stakeholder meetings have been held throughout the duration of the project. In addition, there have been two open house meetings.

Public Involvement

Adoption of the Plan by Elected Officials

The Pima County Board of Supervisors adopted the Ruthrauff Basin Management Study (Resolution 2017-FC 3) on October 3, 2017.

City of Tucson Mayor and Council adopted the Ruthrauff Basin Management Study (Resolution 22833) on October 24, 2017.

Open House Meeting (November 16, 2016)

Pima County Regional Flood Control District held an Open House at the Ellie Towne Flowing Wells Community Center. Materials from the meeting are included below.

Alternatives Workgroup Meeting (June 9, 2015)

Pima County Regional Flood Control District held a Workgroup Meeting to select criteria for multiobjective drainage solutions at the Ellie Towne Flowing Wells Community Center which included the insights of 25 stakeholders.  Results of the Alternatives Workgroup are summarized in the Project Update. Materials from the meeting are included below.

Open House Meeting (December 4, 2014)

Pima County Regional Flood Control District held an Open House at the Ellie Towne Flowing Wells Community Center.  Materials from the meeting are included below.

Neighborhood Leader Stakeholder Meeting (October 23, 2014)

Pima County Regional Flood Control District held a Neighborhood Leader Stakeholder Meeting to review the project scope and get feedback on October 23, 2014 at the Ellie Towne Flowing Wells Community Presentation.  Materials from the meeting are included below.

Government Sector Stakeholder Meeting (July 24, 2014)

Pima County Regional Flood Control District held a Government Sector Stakeholder Meeting to review the project scope and outline on July 24, 2014 at the Joel D. Valdez Main Library. A copy of the Presentation from the meeting and the Project Fact Sheet are available below.

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.