Title
Request Amendment to Intergovernmental Agreement with Flood Control District of Maricopa County and City of Scottsdale for Rawhide Wash Flood Hazard Mitigation Project Construction (Ordinance S-49601)
Description
Request to authorize the City Manager, or his designee, to amend an Intergovernmental Agreement (IGA) with the Flood Control District of Maricopa County (FCDMC) and the City of Scottsdale for the Rawhide Wash Project Construction to revise the cost share allocation among the parties.
Report
Summary
The Rawhide Wash Flood Hazard Mitigation project is defined as the conveyance alternative presented in the Pinnacle Peak West Area Drainage Master Study. The northern limit of the infrastructure is approximately the Rawhide Wash alluvial fan apex located north of Happy Valley Road and the southern limit is the bridge crossing at Pinnacle Peak Road east of Scottsdale Road. The project improvements will include construction of new floodwalls and levees and re-construction of existing floodwalls and levees. Upon completion of this construction project, there will be a submittal of an application for a Federal Emergency Management Agency (FEMA) Letter of Map Revision to revise the apex flow discharge and the re-delineation of the floodplain limits downstream of Scottsdale Road within City of Phoenix jurisdiction. Floodplain re-delineation within City of Phoenix jurisdiction will be based on existing condition drainage infrastructure, development activities, and topography that will reduce the existing Special Flood Hazard Area Zone "AO." After completion of the proposed project, approximately 1,933 acres of land will no longer be designated in a FEMA delineated floodplain. Approximately 80 percent (1,531 acres) of this land is within Phoenix jurisdiction, while the remaining 20 percent (402 acres) are within the City of Scottsdale and unincorporated County areas. The cost share analysis was developed based on flood damage reduction, flood insurance savings, reduced cost of fill for future development and the elimination of redundant infrastructure costs. This resulted in a cost share of 50 percent FCDMC, 40 percent City of Phoenix, and 10 percent City of Scottsdale.
Due to the uncertainty of the market and increasing materials prices, the construction cost of the Project requires an increase from the original estimate of $15 million to $30 million. The FCDMC with the City of Phoenix and City of Scottsdale agreed to modify the project cost share of the delta between the original amount associated with IGA and the final construction cost at 65 percent/35 percent. The 50 percent/50 percent cost share will still apply to the original amount approved by the IGA.
The final design has been finalized and construction is scheduled to be complete in October 2023.
Financial Impact
The revised project construction cost is estimated at $30 million. Of this amount, the City's cost share is estimated to be $10.2 million, with the remainder covered by FCDMC and the City of Scottsdale. Funds are available in the Street Transportation Department's Capital Improvement Program budget. The project is located entirely outside of the City of Phoenix and the City of Scottsdale will be performing the long-term operations and maintenance of the project infrastructure after it is constructed.
Concurrence/Previous Council Action
- On July 6, 2017, Council approved the request to apply for FCDMC funds for Flood Control Projects under the Capital Improvement Project Prioritization Process.
- The Rawhide Wash Project was submitted and approved by the FCDMC on Oct. 25, 2017, for Fiscal Year 2018-19.
- An IGA for the design phase was recommended for approval by the Water, Wastewater, Infrastructure and Sustainability Subcommittee at the Nov. 7, 2018, meeting by a vote of 4-0.
- The original IGA, which covered design, right of way and utility relocation for this project, was approved by the City Council on Dec. 12, 2018 (Ordinance S-45224).
- The IGA for the project construction phase was recommended for approval by the Transportation, Infrastructure and Innovation Subcommittee at the Nov. 6, 2019, meeting by a vote of 4-0.
Location
The northern limit of the project is generally the Rawhide Wash alluvial fan apex located north of Happy Valley Road, and the southern limit is the bridge crossing at Pinnacle Peak Road.
Council Districts: 2 and Out of City
Department
Responsible Department
This item is submitted by Deputy City Manager Alan Stephenson, the Street Transportation Department and the City Engineer.