To: Honorable Mayor and Members of City Council
From: Phil Brun, Utilities Director
Prepared By: Addison LeBlanc, Assistant Engineer
TITLE:
Title
Department of Water Resources Dam Safety and Climate Resiliency Local Assistance Grant Program for Hennessey Spillway Flow Expansion Design Project
LABEL
RECOMMENDED ACTION:
Recommendation
Adopt a resolution authorizing the Utilities Director to submit a proposal, in an amount not to exceed $1,000,000, to obtain funding from the Department of Water Resources Dam Safety and Climate Resiliency Local Assistance Grant Program and to execute the funding agreement, amendments, and all other documents thereto, subject to the availability of matching funds, for the Hennessey Spillway Flow Expansion Design Project and determining that the actions authorized by this resolution are exempt from CEQA under State CEQA Guideline 15378.
Body
DISCUSSION:
Conn Creek Dam was constructed in 1948 and had significant upgrades to the spillway in 1968. Since then, the City and the California Department of Water Resources Division of Safety of Dams (DSOD) have continued annual inspections and maintenance. The City has been submitting engineering analysis and studies to DSOD as part of the annual maintenance inspections which include recommendations that aid in confirming the integrity of the aging infrastructure. The hydrology analysis was reviewed in 1984 and the seismic analysis in 1992.
In addition, GEI Consultants performed spillway condition assessments in 2017 and 2022 as required by the DSOD under the spillway re-evaluation program created in response to the 2017 Oroville Spillway incident. Based on the assessment, repairs to the spillway were performed in 2019 and 2022.
The spillway re-evaluation program includes updates to the hydrologic and hydraulic analysis of the spillway as part of long-term planning. Recent updates to the hydrology reports that are used to analyze the hydraulic capacity of the spillway were incl...
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