Syphon Reservoir Improvement Project

5 Documents in Project


SCH Number
Lead Agency
Irvine Ranch Water District
Document Title
Syphon Reservoir Improvement Project
Document Type
RC - Response to Comments
Present Land Use
The project site’s land use is currently designated as Open Space Reserve in the Orange County General Plan and is zoned as General Agriculture.
Document Description
The proposed Syphon Reservoir Improvement Project (proposed project) would increase the capacity of the existing recycled water reservoir from approximately 500 acre-feet (AF) to 5,000 AF. The proposed project would replace the existing engineered dam with a new engineered dam, increasing the existing 59-foot dam height to 136 feet and increasing the elevation of the dam crest from the existing 388 feet above mean sea level (amsl) to 466 feet amsl. A new spillway would be included with the new dam to protect the reservoir from overtopping. As part of the new design, the engineered embankment dam would include a seepage control drainage system and a circulation system for the reservoir. The existing strainer and disinfection facilities would be demolished, reconstructed and expanded at the toe of the new dam to provide filtration and disinfection. Additional project features include new onsite access and maintenance roads; wetland and riparian mitigation areas; and a potential recreational facility.

Contact Information

Jo Ann Corey
Agency Name
Irvine Ranch Water District
Contact Types
Lead/Public Agency


Irvine, Tustin
Citywide, Countywide, Unincorporated
Cross Streets
Portola Parkway and Sand Canyon Ave
Total Acres
State Highways
133, 241, 261
Stonegate Elementary, Crean Lutheran HS, Eastwood Elementary
Syphon Reservoir, Bee Canyon Wash

Notice of Completion

State Reviewing Agencies
California Air Resources Board (ARB), California Department of Conservation (DOC), California Department of Fish and Wildlife, South Coast Region 5 (CDFW), California Department of Forestry and Fire Protection (CAL FIRE), California Department of Parks and Recreation, California Department of Resources Recycling and Recovery, California Department of Transportation, District 12 (DOT), California Department of Water Resources (DWR), California Governor's Office of Emergency Services (OES), California Highway Patrol (CHP), California Native American Heritage Commission (NAHC), California Natural Resources Agency, California Regional Water Quality Control Board, Santa Ana Region 8 (RWQCB), California State Lands Commission (SLC), Department of Toxic Substances Control, Office of Historic Preservation, State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Water Quality, State Water Resources Control Board, Division of Water Rights, State Water Resources Control Board, Divison of Financial Assistance
Development Types
Other (Reservoir Expansion)
Local Actions
Portola/Sand Canyon Intersection Modification
Project Issues
Aesthetics, Agriculture and Forestry Resources, Air Quality, Biological Resources, Cultural Resources, Cumulative Effects, Drainage/Absorption, Energy, Flood Plain/Flooding, Geology/Soils, Greenhouse Gas Emissions, Growth Inducement, Hazards & Hazardous Materials, Hydrology/Water Quality, Land Use/Planning, Mandatory Findings of Significance, Mineral Resources, Noise, Population/Housing, Public Services, Recreation, Schools/Universities, Septic System, Sewer Capacity, Solid Waste, Transportation, Tribal Cultural Resources, Utilities/Service Systems, Vegetation, Wetland/Riparian, Wildfire


Final Document(s) [Approved_Certified draft environmental documents]

Disclaimer: The Governor’s Office of Planning and Research (OPR) accepts no responsibility for the content or accessibility of these documents. To obtain an attachment in a different format, please contact the lead agency at the contact information listed above. You may also contact the OPR via email at or via phone at (916) 445-0613. For more information, please visit OPR’s Accessibility Site.

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