DR-4407-CA Public Notice 007

INITIAL PUBLIC NOTICE: Regional Sewer Lift Station Replacement Project, Orange County, California | HMGP 4407-291-118

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 to the Moulton Niguel Water District (MNWD) in Orange County, California, to provide seismic and flood hazard mitigation. The proposed action would reduce the risk of raw sewage spills during seismic and severe storm events by relocating and replacing wastewater force mains within the Laguna Niguel Regional Park. Pursuant to Executive Order 11988 (Floodplain Management), Executive Order 11990 (Wetlands 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 intent to carry out an action affecting a floodplain and wetland.

The purpose of the proposed action is to reduce seismic and flood hazards. The proposed action consists of replacing two existing force mains with a more durable material; increasing the size of the force mains; relocating the force mains to a new alignment along the east side of Sulphur Creek Reservoir; and repurposing one of the existing force mains to be a gravity-only effluent transmission main for emergency use. The new alignment would begin at MNWD’s Regional Lift Station and terminate at the South Orange County Wastewater Authority’s Joint Regional Treatment Plant directly south of the park. Project coordinates are: 33.551937, -117.717325 (northwest end point) and 33.541578, -117.704011 (southeast end point). New pipelines would be installed using open trench methods and trenchless methods at creek and stream crossings. Trenchless installation methods would likely include microtunneling or jack and bore construction and would be used to avoid impacting streams and wetlands where feasible.

The project area is in the 100-year floodplain as depicted on the FEMA Flood Insurance Rate Map (FIRM) Number 06059C0437J, effective date December 3, 2009. The FIRM shows that the project area partially lies within Zone AE, an area that has a 1-percent probability of flooding every year and where predicted floodwater elevations have been established, and partially in Zone A, an area that has a 1-percent probability of flooding every year and where predicted floodwater elevations have not been established. A small portion of the project area also lies within a floodway.  

The U.S. Fish and Wildlife Service National Wetlands Inventory map shows freshwater forested/shrub wetlands along Sulphur Creek. A biological site survey in 2017 identified a total of approximately 0.94 acres of potential wetlands in the study area. The project would temporarily impact approximately 0.007 acres of potential wetlands.

Additional information about FEMA’s proposed action, including maps showing the potential impacts on floodplains and wetlands, may be obtained 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 within 15 days after publication of this notice.