REPORT/RECOMMENDATION TO THE BOARD OF SUPERVISORS
OF SAN BERNARDINO COUNTY FLOOD CONTROL DISTRICT
AND RECORD OF ACTION
March 24, 2026
FROM
NOEL CASTILLO, Chief Flood Control Engineer, Flood Control District
SUBJECT
Title
Initial Study/Mitigated Negative Declaration for the Rialto Channel Flood Control Improvement Project
End
RECOMMENDATION(S)
Recommendation
Acting as the governing body of the San Bernardino County Flood Control District:
1. Certify that the Initial Study and Mitigated Negative Declaration for the Rialto Channel Flood Control Improvement Project, located in the City of Rialto, State Clearinghouse No. 2026010838, has been completed in compliance with the California Environmental Quality Act, has been reviewed and considered prior to approving the Project, and reflects the independent judgment of the Board of Supervisors.
2. Adopt the Initial Study and Mitigated Negative Declaration for the Rialto Channel Flood Control Improvement Project, located in the City of Rialto.
3. Adopt the Mitigation Monitoring and Reporting Program for the Rialto Channel Flood Control Improvement Project, as provided in the Initial Study and Mitigated Negative Declaration.
4. Approve the Rialto Channel Flood Control Improvement Project, located in the City of Rialto, as defined in the Initial Study and Mitigated Negative Declaration.
5. Direct the San Bernardino County Flood Control District to file the Notice of Determination in accordance with the California Environmental Quality Act.
(Presenter: Noel Castillo, Chief Flood Control Engineer, 387-7906)
Body
COUNTY AND CHIEF EXECUTIVE OFFICER GOALS & OBJECTIVES
Provide for the Safety, Health and Social Service Needs of County Residents.
FINANCIAL IMPACT
Approval of this item will not result in the use of Discretionary General Funding (Net County Cost). The San Bernardino County Flood Control District (District) is funded by property taxes, fees, and other local, state, and federal funding. The requested administrative actions have minimal financial impact on the District. Sufficient appropriation and revenue are included in the District’s 2025-26 budget (1920002522 F01669).
BACKGROUND INFORMATION
The Rialto Channel Flood Control Improvement Project (Project), located between Willow Avenue and Etiwanda within the City of Rialto, proposes to improve flood protection and public safety by enhancing the hydraulic performance and structural integrity of the existing flood control channel. The Project is intended to address existing capacity constraints and aging infrastructure while maintaining the channel’s primary flood control function. The Project will not induce new development or increase stormwater runoff beyond existing conditions.
The existing Rialto Channel is part of the regional flood control system and was originally constructed to convey stormwater flows from upstream urbanized areas. Portions of the channel no longer meet current engineering and flood protection standards due to age, sediment accumulation, and structural deficiencies. During major storm events, these limitations reduce conveyance efficiency and increase the risk of localized flooding and maintenance challenges.
The proposed Project includes channel improvements and associated appurtenant features designed to restore and enhance flood conveyance capacity and long-term operational reliability. Improvements are focused on maintaining existing flood control functions while improving safety, durability, and maintenance access. The Project is funded by local sources and is subject to compliance with the California Environmental Quality Act (CEQA).
An Initial Study/Mitigated Negative Declaration (IS/MND) and a Notice of Intent/Notice of Availability were prepared for the Project and circulated for a period of 30 days beginning on January 20, 2026, through the Office of Land Use and Climate Innovation (formerly, Office of Planning and Research), State Clearinghouse. During the 30-day public review period, one comment letter was received. The comment was reviewed and considered prior to finalization of the IS/MND and did not result in any changes to the impact analysis or conclusions of the environmental document. The comment letter is included in the administrative record. A Notice of Intent was also distributed to responsible and trustee agencies, interested parties, and surrounding property owners, with the completed draft of the IS/MND made available for the same 30-day period beginning on January 20, 2026. Mitigation measures determined to be needed to reduce potential impacts to the lowest level possible were included in a Mitigation Monitoring and Reporting Program included as Section 1.5 of the IS/MND entitled “Summary of Mitigation Measures.”
Under CEQA, an environmental review must be completed prior to Project approval and implementation. As the lead agency, the District Board is the appropriate authority to consider adoption of the environmental document.
The Project supports the County’s goal of providing for the safety, health, and social service needs of County residents by maintaining essential flood control infrastructure, protecting public safety, and reducing flood risk to existing communities and regional drainage systems.
PROCUREMENT
Not applicable.
REVIEW BY OTHERS
This item has been reviewed by County Counsel (Sophie Curtis, Deputy County Counsel, 387-5455) on February 4, 2026; and County Finance and Administration (Kathleen Gonzalez, Administrative Analyst, 387-5412) on March 6, 2026.