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| Information |
| TITLE: |
| Consideration and Adoption of Resolution No. 2023-53: A resolution authorizing an Intergovernmental Agreement (IGA) between the City of Flagstaff and the State of Arizona, acting by and through the Department of Transportation (ADOT) for US180 at Schultz Creek Drainage Maintenance. |
| STAFF RECOMMENDED ACTION: |
- Read Resolution No. 2023-53 by title only
- City Clerk reads Resolution No. 2023-53 by title only (if approved above)
- Adopt Resolution No. 2023-53
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| Executive Summary: |
| City will be responsible to design, advertise, award, and administer construction of a new drainage system and appurtenances at US180 and Schultz Creek to alleviate post-fire flooding caused by the 2022 Pipeline Fire. The City will be required to obtain an encroachment permit from the State to complete the project and be responsible for actual costs, any new right of way and temporary construction easements, operations, and maintenance of the project. This IGA also provides for maintenance of the interim condition infrastructure including a restrictive plate that prevents a “bubbler” overflow situation near Northwood Apartments. The interim condition infrastructure will be removed, or bypassed, during the construction of the new drainage system. |
| Financial Impact: |
| Cost of permitting, design, construction, and future operations and maintenance of the project. The State will review the City's project design plans and provide an inspector for the potion of the City's project within the ADOT right of way at no additional cost to the city. City funding for the permitting, design, and construction is secured through a FY24 State appropriations, future operations and maintenance will be funded out of the City Stormwater Utility. |
| Policy Impact: |
| None |
| Connection to PBB Priorities/Objectives, Carbon Neutrality Plan & Regional Plan: |
| Priority Based Budget Key Community Priorities and Objectives
Sustainable Innovative Infrastructure - Deliver outstanding services to residents through healthy well maintained infrastructure system
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| Has There Been Previous Council Decision on This: |
| No, this is a distinct IGA between the State and the City for a singular stormwater conveyance structure at US180. |
| Options and Alternatives: |
- Approve the IGA for the drainage maintenance
- Do not approve the IGA which could result in the project not proceeding and could cause future flooding risks. |
| Background/History: |
| In summer 2023 the State constructed improvements and repairs of the existing storm drainage system along US180 and added a new 48-inch line perpendicular to the US180 from the right of way to the Rio de Flag. These repairs were required due to ground subsidence and pipe failure during spring 2023. The repairs and improvements were intended as an interim condition until proper funding and design was brought forward to mitigate flood impacts from the upstream 2022 Pipeline Fire. As part of the interim improvement the State installed, at the City’s request, a flow restriction plate within the box culvert at the entrance to the 48-inch existing line paralleling US180 to the south, this plate prevents a “bubbler” condition near the Northwood Apartments due to a further constriction in the pipe. The city will be responsible for any effects caused solely by the restrictive plate that are unanticipated, including but not limited to cleanup of any debris within the roadway. The city will remove the restrictor place, at the city’s expense, upon mutual agreement of both parties, should the restrictor place cause unanticipated negative impacts. The future improvement will remove, or bypass, this section of stormwater infrastructure including the plate, making the previous sentences nullified. |
| Key Considerations: |
| City will submit an encroachment permit for related pre-construction activities as needed, and an encroachment permit application for routine maintenance and emergency work. |
| Community Benefits and Considerations: |
| The project will provide much needed mitigation from future flooding to downstream neighborhoods, conveying up to the 100 year post-fire flood in Schultz Creek. The interim conditions provide partial flood mitigation, approximately 200 CFS more capacity than pre-2023. |
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