Syphon Reservoir Improvement Project

2 Documents in Project


SCH Number
Lead Agency
Irvine Ranch Water District
Document Title
Syphon Reservoir Improvement Project
Document Type
EIR - Draft EIR
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 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
Irvine Ranch Water District
Lead/Public Agency / Project Applicant
15600 Sand Canyon Ave
Irvine, CA 92618

Phone : (949) 453-5300


33°42'38"N 117°43'52"W
Irvine Tustin
Citywide Countywide
Cross Streets
Portola Parkway and Sand Canyon Ave
Total Acres
Parcel #
State Highways
133, 241, 261
Stonegate Elementary, Crean Lutheran HS, Eastwood Elementary
Syphon Reservoir, Bee Canyon Wash

Notice of Completion

Review Period Start
Review Period End
Development Type
Water Facilities (Reservoir Expansion)(Type Reservoir, MGD 4.47)
Local Action
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 GHG/Energy
Reviewing Agencies
California Air Resources Board (ARB) California Department of Conservation (DOC) 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 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 California Department of Fish and Wildlife, South Coast Region 5 (CDFW) California Department of Transportation, District 12 (DOT)


Draft Environmental Document [Draft IS, NOI_NOA_Public notices, OPR Summary Form, Appx,]
_Memo Updated Information   PDF 232 K Syphon Reservoir Draft EIR   PDF 127197 K Syphon Reservoir Draft EIR Appendices   PDF 112284 K Syphon Reservoir NOA_03   PDF 9592 K Updated Appendix E_Transportation Impact Analysis_Oct 2020   PDF 6845 K
Notice of Completion [NOC] Transmittal form
Syphon DEIR NOC_signed   PDF 930 K
State Comment Letters [Comments from state reviewing agencies]
2019080009_CDFW Comment   PDF 445 K 2019080009_DOT Comment   PDF 282 K

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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