Vote — approved

Jack Sellers	yes
Thomas Galvin	yes
Bill Gates	yes
Clint Hickman	yes
Steve Gallardo	yes

Ayes: Jack Sellers, Thomas Galvin, Bill Gates, Clint Hickman, Steve Gallardo

Item Text

116. FEASIBILITY COST SHARE AGREEMENT FOR CAVE BUTTES DAM SAFETY IMPROVEMENTS Approve Feasibility Cost Share Agreement (FCSA) for contract number FCD2024G001 for the feasibility study for dam safety improvements at Cave Buttes Dam. The FCSA projected study cost is $3,000,000. The District's cost share as presented in the FCSA is in the amount of $1,500,000 and represents a 50% cost share between the Flood Control District of Maricopa County (FCDMC) and the United States Army Corps of Engineers (USACE). The funds are required to proceed with a feasibility study to assess suitability of dam safety improvements at Cave Buttes Dam including a seepage collection system. The documents included are the main FCSA and Certification Regarding Lobbying. Cave Buttes Dam is an earthen embankment dam located in Maricopa County, southwest of the intersection of North Cave Creek Road and East Jomax Road, approximately 19 miles north of Downtown Phoenix. It was constructed by USACE between 1977 to 1980 and consists of the main embankment, three additional earthen dikes, and an unlined emergency spillway that act as one hydraulically connected system that impounds stormwater from a 191 square mile drainage basin and protects over 250,000 residents and approximately $15,000,000,000 worth of property including the State of Arizona capitol complex. A water seepage was observed at the left abutment of the dam during 1993 and 2010 storm events. The Cave Buttes Modification Project was initiated by the District to analyze alternatives to improve dam safety features. Several potential dam safety improvements were developed. One of these is an auxiliary outlet structure that finished construction in 2021. Another alternative developed was a seepage collection system designed to mitigate against a concentrated leak failure at the left dam abutment. The seepage collection system would be the focus of the USACE feasibility study as well as taking a holistic appraisal of potential safety improvements at Cave Buttes Dam. This agenda item impacts supervisorial districts 3, 4, and 5. (C-69-25-001-X-00) 117. IGA WITH THE CITY OF PHOENIX FOR THE NORTH 20TH STREET AT LOOKOUT MOUNTAIN PARK DRAINAGE MITIGATION PROJECT Approve Intergovernmental Agreement (IGA) FCD 2023A006 for North 20th Street at Lookout Mountain Park Drainage Mitigation Project (Project) between the City of Phoenix (City) and the Flood Control District of Maricopa County (District). The estimated total Project cost is $1,000,000. The District’s estimated share of the Project cost is $750,000; the City estimated share of the Project cost is $250,000. The City will operate and maintain the completed Project. This Agreement shall become effective as of the date it has been executed by all PROJECT PARTNERS and shall expire two years from that date, or upon Project completion, whichever occurs first. The City proposed the Project for the District’s evaluation under the District’s Small Project Assistance Program for Fiscal Year 2024. This IGA is proposed in accordance with the terms of the Small Project Assistance Program, adopted by the Board under Resolution FCD 2022R003 (C-69-23-013-X-00). The North 20th Street at Lookout Mountain Park Drainage Mitigation Project includes installation of a 36-inch pipe which will drain the new catch basin through the concrete channel with a bubble up structure. This Agenda Item impacts Supervisorial District 3. (C-69-25-002-X-00)

Attachments (2)

Vote — approved

Jack Sellers	yes
Thomas Galvin	yes
Bill Gates	yes
Clint Hickman	yes
Steve Gallardo	yes

Ayes: Jack Sellers, Thomas Galvin, Bill Gates, Clint Hickman, Steve Gallardo

Item Text

116. FEASIBILITY COST SHARE AGREEMENT FOR CAVE BUTTES DAM SAFETY IMPROVEMENTS Approve Feasibility Cost Share Agreement (FCSA) for contract number FCD2024G001 for the feasibility study for dam safety improvements at Cave Buttes Dam. The FCSA projected study cost is $3,000,000. The District's cost share as presented in the FCSA is in the amount of $1,500,000 and represents a 50% cost share between the Flood Control District of Maricopa County (FCDMC) and the United States Army Corps of Engineers (USACE). The funds are required to proceed with a feasibility study to assess suitability of dam safety improvements at Cave Buttes Dam including a seepage collection system. The documents included are the main FCSA and Certification Regarding Lobbying. Cave Buttes Dam is an earthen embankment dam located in Maricopa County, southwest of the intersection of North Cave Creek Road and East Jomax Road, approximately 19 miles north of Downtown Phoenix. It was constructed by USACE between 1977 to 1980 and consists of the main embankment, three additional earthen dikes, and an unlined emergency spillway that act as one hydraulically connected system that impounds stormwater from a 191 square mile drainage basin and protects over 250,000 residents and approximately $15,000,000,000 worth of property including the State of Arizona capitol complex. A water seepage was observed at the left abutment of the dam during 1993 and 2010 storm events. The Cave Buttes Modification Project was initiated by the District to analyze alternatives to improve dam safety features. Several potential dam safety improvements were developed. One of these is an auxiliary outlet structure that finished construction in 2021. Another alternative developed was a seepage collection system designed to mitigate against a concentrated leak failure at the left dam abutment. The seepage collection system would be the focus of the USACE feasibility study as well as taking a holistic appraisal of potential safety improvements at Cave Buttes Dam. This agenda item impacts supervisorial districts 3, 4, and 5. (C-69-25-001-X-00) 117. IGA WITH THE CITY OF PHOENIX FOR THE NORTH 20TH STREET AT LOOKOUT MOUNTAIN PARK DRAINAGE MITIGATION PROJECT Approve Intergovernmental Agreement (IGA) FCD 2023A006 for North 20th Street at Lookout Mountain Park Drainage Mitigation Project (Project) between the City of Phoenix (City) and the Flood Control District of Maricopa County (District). The estimated total Project cost is $1,000,000. The District’s estimated share of the Project cost is $750,000; the City estimated share of the Project cost is $250,000. The City will operate and maintain the completed Project. This Agreement shall become effective as of the date it has been executed by all PROJECT PARTNERS and shall expire two years from that date, or upon Project completion, whichever occurs first. The City proposed the Project for the District’s evaluation under the District’s Small Project Assistance Program for Fiscal Year 2024. This IGA is proposed in accordance with the terms of the Small Project Assistance Program, adopted by the Board under Resolution FCD 2022R003 (C-69-23-013-X-00). The North 20th Street at Lookout Mountain Park Drainage Mitigation Project includes installation of a 36-inch pipe which will drain the new catch basin through the concrete channel with a bubble up structure. This Agenda Item impacts Supervisorial District 3. (C-69-25-002-X-00)