DR-4558-CA Final Public Notice Western Municipal Water District

FINAL PUBLIC NOTICE: Western Municipal Water District (Western), South Regional Pump Station, Riverside County | HMGP 4558-252-026

The U.S. Department of Homeland Security’s Federal Emergency Management Agency (FEMA) intends to provide Federal financial assistance under the Hazard Mitigation Grant Program (HMGP) to the South Regional Pump Station in Riverside County, California. Under Executive Orders 11988 and 11990, FEMA is required to provide a public notice of any proposed actions in or affecting floodplains or wetlands. This notice serves as FEMA’s funding action located within the floodplain and implementing regulations at 44 CFR Part 9. FEMA hereby provides interested parties with a notice of its intent to carry out an action affecting a floodplain.

The purpose of the project is to install a permanent emergency generator at the Western South Regional Pump Station. Project location: 671 North Atlantic Boulevard City of Corona (GPS coordinates: 33.893571, -117.577626). The 600 kW permanent generator will be installed in tandem with, and on top of a 1-foot concrete pad. This brings the elevation of the generator to 578 feet above sea level, 4 feet above the maximum 100-year floodplain elevation for the area. The generator will also require the excavation and installation of a new duct bank, and installation of a portable bypass pump connection. All the work will be conducted within the footprint of the existing facility. The permanent system will supply backup power in the event of electrical power loss, allowing the pump station to continue moving sewage to the treatment plant.

The project is located within the 0.2% Flood Hazard Area (500-year floodplain). Confirmation of location in the Flood Hazard Area (SFHA) was determined by the Riverside County Flood Insurance Rate Map (FIRM) panel 06065C0689H, dated 09/12/2025. There is a potential for the facility to be impacted by future flooding events due to its location within the Shaded X, an area between the limits of the 1-percent chance and the 0.2 percent annual chance of flood. The proposed work will not take place in wetlands per the United States Fish and Wildlife Service National Wetlands Inventory.

Project Alternatives:
Alternative #1: Relocating the facility is not currently a consideration, as doing so would require dismantling the pipelines and utilities that currently support it and replacing them. The relocation option is not socially and economically feasible.
Alternative #2: If the permanent generator is not installed, wastewater (sewer) services could be interrupted during a loss of electrical power. The South Regional Pump Station was built to collect and move wastewater to the WRCRWA treatment plant. The no action alternative is not feasible.

Alternative #3: Installing the permanent generator and raising it above the Base Flood Elevation (BFE) will not only prevent future interruptions to sewer collection and treatment in the event of power loss but will also prevent damage to the generator during a future flood. The proposed project aims to reduce risk by providing a backup power system for resiliency and minimizing system downtime after a power loss. This option is the best socially and economically feasible alternative.

Additional information about FEMA’s proposed action, including maps showing the potential impacts on floodplains, may be obtained in writing. Comments are solicited from the public, local, state or federal agencies, and other interested parties in order to consider and evaluate the impacts of the proposed project. The comments should be made in writing and addressed to the FEMA Region IX, Regional Environmental Officer, 111 Broadway Suite 1200, Oakland, California 94607, or may be emailed to fema-rix-ehp-documents@fema.dhs.gov. All comments must be submitted to the FEMA Region IX Office within 15 days after publication of this notice.