PUBLIC NOTICE 
NORCO BLUFFS BANK STABILIZATION PROJECT OPERATION, MAINTENANCE, REPAIR, REPLACEMENT AND REHABILITATION MANUAL
Pursuant to the National Environmental Policy Act (NEPA), the U.S. Army Corps of Engineers, Los Angeles District (USACE) is preparing a Supplemental Environmental Assessment (SEA) to evaluate potential environmental impacts related to the completion and implementation of an Operation, Maintenance, Repair, Replacement and Rehabilitation (OMRR&R) manual for the completed Norco Bluffs Bank Stabilization Project (Proposed Action). If the SEA identifies significant impacts that cannot be reduced or avoided to a level that is less than significant, USACE would prepare an Environmental Impact Statement. If no unmitigable, significant impacts are identified, then USACE would prepare a Finding of No Significant Impact (FONSI).
Purpose and Description of the Proposed Action
The Norco Bluffs Bank Stabilization Project, completed in 2003, provides bank and slope protection against erosion for an approximately 1-mile reach along the south bank of the Santa Ana River in the City of Norco, Riverside County, California (Figure 1). The Project also includes a system of v-ditches and terrace drains along the length of the buttress fill to convey surface water offsite. In 2024-2025, the USACE repaired erosion damage that occurred to the buttress fill, storm drain pipes, terrace drains, and v-ditches subsequent to Project construction. These repairs returned the project to a complete and functional status. The OMRR&R manual defines and guides future, ongoing maintenance and repair actions that would be implemented by the Riverside County Flood Control and Water Conservation District (District), the non-Federal Project sponsor. The Proposed Action consists of finalizing the OMRR&R manual and transferring maintenance responsibility to the District. Routine inspections and maintenance as described in the OMRR&R manual would not normally extend beyond the existing Project footprint, although indirect effects that could occur within a 100-foot adjacent buffer zone (shown in Figure 1) would also be evaluated. Examples of routine maintenance activities include nuisance vegetation removal from constructed features, sediment removal from concrete drainages, fence and gate repairs, and regular inspections of the site.
Environmental Impacts and Environmental Compliance
Environmental resources that would be analyzed for effects from the proposed project modification include, biological resources, noise, traffic, air quality, water quality, land use, aesthetics, recreation, cultural resources and public safety.
The USACE has developed measures to minimize and avoid impacts to the resources listed above resources. It is anticipated that potential impacts to environmental resources would be less than significant. The USACE has been coordinating the Proposed Action with the U.S. Fish and Wildlife Service. No effects to Federally listed Threatened or Endangered Species are anticipated. The USACE has also completed consultation with local tribes and the State Historic Preservation Officer on the Proposed Action pursuant to Section 106 of the National Historic Preservation Act.
The USACE is soliciting comments from the public, federal, state, and local agencies, and other interested parties. By providing substantive, site-specific comments to USACE, you provide information that supports USACE’s decision-making process. All comments received during the comment period become part of the record and will be considered in the decision.
Comments will be accepted from February 27 to March 20, 2025. Comments can be submitted electronically to: Marissa.C.McGowan@usace.army.mil.
