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Regular Agenda Item 3. O.

Regular BOS Meeting

Meeting Date:	04/07/2020
Submitted For:	Homero Vela	Submitted By:	Homero Vela, Assistant County Manager
Department:	Assistant County Manager
Fiscal Year:	FY 19-20 and FY 20-21	Budgeted?:	No
Contract Dates Begin & End:	March 26, 2020 - March 25, 2022	Grant?:	No
Matching Requirement?:	Yes	Fund?:	New

Information

Request/Subject

The County recently shared with the Town of Payson its plans for the new County Complex at Frontier and S.R. 87 in Payson. During this exchange, an opportunity for partnership regarding regional drainage was discussed by staff members from the Town of Payson and Gila County.

Background Information

The Town of Payson Master Drainage Plan, 2000, provided an assessment of drainage flows and improvement alternatives for the Town of Payson. The West Bonita Street basin area is in the center of the project area. It encompasses the southern portion of the Payson North residential subdivision, the commercial properties along S.R. 87 south of the intersection with S.R. 260, and adjacent residential areas. The watershed area includes 609 acres. The existing drainage system is a combination of open channels and underground culverts. The capacity of the drainage system is significantly undersized resulting in surface runoff. During heavy rainfall events, the surface runoff impacts to traffic along S.R. 87 and poses risk of flooding for residents and commercial and government buildings in the downstream section of the basin area including the existing county facilities in this area, including the existing Court building at 714 A S Beeline Highway and the Sheriff's office at 108 W Main Street.

Evaluation

Staff members from the Town of Payson and Gila County have worked collectively to develop a proposed conveyance route. The route was selected based on the most efficient and highest-capacity routing while avoiding costly utility obstructions/relocations. A drawing depicting the route is attached – refer to PDF- Payson GC Storm Drain. Using the proposed route, the engineering staff from all agencies, working with Kimley Horn, have determined the following cost estimate:

Cost to Design - $75,000
Cost to Construct - $925,000

Conclusion

The regional drainage improvement proposed by this Intergovernmental Agreement (IGA) will help reduce the surface water flows in this area of the Town of Payson and mitigate potential flooding for existing County building in the area and minimize the depth of ponding on the County parking lots.

Recommendation

Staff recommends approval of the IGA and funding of a not-to-exceed cost of $500,000 to design and construct the underground conveyance system.

Suggested Motion

Information/Discussion/Action to approve the Intergovernmental Agreement between the Town of Payson and Gila County to fund the design and construction cost of the proposed storm drainage project not to exceed $500,000 for Gila County. (Homero Vela)

Attachments
IGA Gila County/Town of Payson
Conveyance Routing
Regional Drainage Cost