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File #: 325-2024    Version: 1 Name:
Type: Consent Calendar Status: Passed
File created: 8/30/2024 In control: CITY COUNCIL OF THE CITY OF NAPA
On agenda: 10/1/2024 Final action: 10/1/2024
Title: Department of Water Resources Dam Safety and Climate Resiliency Local Assistance Grant Program for Hennessey Spillway Flow Expansion Design Project
Attachments: 1. ATCH 1 - Resolution

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 included in an amended report and submitted to DSOD for review of the probable max flood (PMF).  DSOD’s review confirmed the report’s findings that the spillway capacity needs to be increased to meet current design standards. DSOD requested the analysis be further refined with feasibility and alternatives analysis to meet modern design standards and address the deficiency.

 

Recognizing that the requirements of DSOD for the spillway upgrades require a large capital investment, the Water Division is seeking funding through applications to state and federal entities for procuring the necessary long-term capital for the successful planning, design, and construction of a project to meet the state requirement of a spillway that can meet the probable maximum flood and bolster the water supply for the long-term future.

 

The State has recognized many agencies are unable to financially support the requirements of aging dam infrastructure based on the spillway re-evaluation program, so Senate Bill 122 was passed with the Dam Safety and Climate Resilience Local Assistance Program to establish funding of repairs, rehabilitation, and other dam safety projects to address the deficiencies identified in the spillway re-evaluation program. This is the first year for applications with initial funding of $47.5 million dollars with a required cost-share up to a maximum of 50%.

 

Staff recommends that the City Council adopt a resolution to authorize the Utilities Department to seek $1,000,000 in funding under this grant program. If awarded, the grant proceeds will provide partial funding for the feasibility studies and engineering design plans, specifications, and documents for the Hennessey Spillway Flow Expansion Design Project.

 

FINANCIAL IMPACTS:

The estimated cost for feasibility studies and engineering design is $1.5 million to $2.0 million.  Funds in the amount $994,942 are currently available in the Hennessey Spillway Flow Expansion Design budget account (63WS23UT01).  If the City receives grant funding from the program identified herein, this budget account will be used to provide the required matching cost-share funds.  If the grant funds are awarded, the ability to execute a funding agreement will be subject to availability of funding in this account to provide the required cost-share based on the actual grant award.  If sufficient funds are available, the funding agreement can be executed pursuant to the terms of the adopted resolution.  Otherwise, staff will need to seek Council authorization to execute the final funding agreement.

 

CEQA:

The Utilities Director has determined that the Recommended Action described in this Agenda Report is not in-and-of-itself a “project” (pursuant to CEQA Guidelines Section 15378) since it does not result in a physical change in the environment and relates more to a government fiscal activity.

 

However, the Recommended Action is a part of a potential larger future “project” that will be subject to environmental review in accordance with CEQA at the “earliest feasible time” prior to “approval” consistent with CEQA Guidelines Sections 15004 and 15352. The larger “project” is Hennessey Spillway Flow Expansion (budget account 63WS27UT02), and staff plans to bring back a CEQA analysis to Council prior to potential approval to construct the Project.

 

DOCUMENTS ATTACHED:

ATCH 1 - Resolution

 

NOTIFICATION:

None.