Title
Request Authorization to Accept Funding and Enter into an Intergovernmental Agreement with the Flood Control District of Maricopa County for the Fiscal Year 2027 Capital Improvement Program - 35th Avenue and Dobbins Road Storm Drain Project - District 8
Description
Request authorization for the City Manager, or his designee, to accept funding and enter into an intergovernmental agreement with the Flood Control District of Maricopa County (FCDMC) to accept funding for the 35th Avenue and Dobbins Road Storm Drain Project (“Project”). Further request granting an exception pursuant to Phoenix City Code § 42-20 and authorizing inclusion in the transaction documents indemnification and assumption of liability provisions that would otherwise be prohibited by Phoenix City Code § 42-18. Further request authorization for the City Treasurer to accept and the City Controller to disburse all funds related to this item. The City's estimated cost share for the Project design will not exceed $325,000.
Report
Summary
In 2015, the FCDMC and the City of Phoenix initiated a study (“the Study”) to update the Laveen Area Drainage Master Plan (LADMP). The Study incorporated data from the August-September 2014 storms and evaluated existing regional drainage facilities, including detention basins, channels, storm drains, and culverts.
Completed in December 2017, the Study quantified drainage issues, sources, and hazards using updated two-foot contour mapping and two-dimensional modeling. It identified new flooding concerns not captured in the 2002 LADMP, reevaluated previous mitigation measures, compared alternatives, and recommended new drainage master plan elements for inclusion in the LADMP update. Specifically, the Study recommended extending regional drainage infrastructure further into the watershed to address neighborhood flooding revealed during the 2014 storms.
One such recommendation involves construction of a new culvert near the Aguila Golf Course (the “Project”). The golf course was constructed with 135 acre-feet of detention storage under a 1997 agreement between the City, FDMC, and the golf course developer. However, the Study’s FLO 2D model shows that only 39 acre-feet reach the course during a 100-year storm. The proposed culvert will deliver up to an additional 42 acre-feet, significantly reducing flooding at Dobbins Road and 35th Avenue and adjacent properties. It will also allow controlled inflow to the golf course, preventing erosion caused by uncontrolled overtopping of the roadways.
The Project will be incorporated into the City’s broader Dobbins Road improvements. Final design may require adjustments in feature size, type, and location and will involve coordination with existing utilities-water, sewer, and SRP irrigation and power-as well as intersection modifications. The Project will also address the impacts of increased flow frequency and volume on the golf course. Once completed, the Project will provide 100-year flood protection to properties in the Project area.
In December 2024, Floodplain Management staff submitted an application for the Project to the FCDMC Capital Improvement Program (CIP). The CIP identifies potential projects for FCDMC participation and cost-share opportunities for project development and implementation, subject to budget availability and FCDMC Board approval. Projects selected by FCDMC are then implemented via intergovernmental agreements between the project partners. Council authorization under this item would allow the City to enter into an intergovernmental agreement with FCDMC to access funding for the Project, accept that funding, and then disburse that funding.
Financial Impact
The estimated Project design costs are $650,000. Under the IGA between the City and the FCDMC, the City and FCDMC will jointly cost-share project development and implementation. The cost-share distribution between the City of Phoenix and FCDMC for this project will remain 50/50, the standard allocation for FCDMC-funded projects. The City's contribution of up to $325,000 is available through the City's Street Transportation Department's Capital Improvement Program.
Location
The project is generally located at the intersection of 35th Avenue and Dobbins Road
Council District: 8
Department
Responsible Department
This item is submitted by City Manager Ed Zuercher, Deputy City Manager Frank McCune, and the City Engineer.