Final Public Notice: Kimball Reservoir Intake Tower Drain Valve and Piping Improvements

FINAL PUBLIC NOTICE

KIMBALL RESERVOIR INTAKE TOWER DRAIN VALVE AND PIPING IMPROVEMENTS
NAPA COUNTY, CALIFORNIA
HMGP-4353-078-053

The U.S. Department of Homeland Security’s Federal Emergency Management Agency (FEMA) proposes to provide federal financial assistance under the Hazard Mitigation Grant Program to the City of Calistoga in Napa County, California, to mitigate the vulnerabilities of Kimball Reservoir to earthquake and flood hazards by retrofitting the intake and drain valve systems at Kimball Creek Dam (proposed action). Pursuant to Executive Order 11988 (Floodplain Management) and FEMA’s implementing regulations at Title 44 of the Code of Federal Regulations Part 9, FEMA hereby provides interested parties with a notice of its final decision and an explanation of the alternatives that were considered.

The purpose of the proposed action is to reduce the risk of potential catastrophic dam failure. The proposed action consists of the following: 1) replacing the existing intake with a sloped intake; 2) replacing the existing drain valve and vault; 3) installing a new PVC pipeline inside the existing outlet pipe; 4) replacing the existing water treatment plant (WTP) outlet pipe; 5) improving the piping and flowmeter components of the existing fish bypass system; and 6) improving the existing access road. The proposed action would use a staging area, approximately 4.56 acres, with no grading required to prepare the site. However, excavation spoils from the new drain valve and WTP pipeline improvements would be spread evenly throughout the construction staging area.

The project area is depicted on the FEMA Flood Insurance Rate Map (FIRM), Map Number 06055C0230E, effective September 26, 2008. The western portion of the staging area and the southern portion of the access road lie within Zone A, an area that has a 1-percent probability of flooding every year.

A map of the project area and its location within the floodplain is available for public inspection. Parties interested in receiving a copy of the map should contact the FEMA Region IX Environmental Officer using contact information provided in this notice.

Two alternatives to the proposed action were considered: Alternative 1, No Action; and Alternative 2, Replacement Intake Tower. Under Alternative 1, there would be no retrofit of the intake and drain valve systems at Kimball Creek Dam. This Alternative is not recommended because it would leave the City of Calistoga at risk for water supply disruption during natural disaster situations. Alternative 2 included constructing a new, replacement free-standing intake tower. This Alternative is not recommended due to the high costs related to constructing a new concrete base and the additional environmental permitting for the construction of a new walkway structure in the reservoir. FEMA has determined that the proposed project is the only practicable alternative available; therefore, the proposed action must be located in the floodplain. The proposed action would have no significant adverse impact on the floodplain and would benefit the area by reducing the risk of flooding and flood damage. Therefore, measures to minimize impacts on the floodplain are not necessary. The City of Calistoga has declared that the proposed action conforms to local floodplain standards, and would be responsible for the management, construction, and maintenance of the proposed action. 

Additional information about FEMA’s proposed action may be requested by writing the FEMA Region IX Environmental Officer at FEMA, 1111 Broadway, Suite 1200, Oakland, California 94607, or fema-rix-ehp-documents@fema.dhs.gov, or calling (510) 627-7027. All requests should be received no later than 15 days after publication of this notice. No action will be taken before this date.