Carlson Marsh Regrade Project

3 Documents in Project


SCH Number
Lead Agency
Irvine Ranch Water District
Document Title
Carlson Marsh Regrade Project
Document Type
NOD - Notice of Determination
Present Land Use
Open Space and Preservation

Document Description
The project proposes to remove exotic vegetation and construct or modify weirs and culverts at several locations to allow for circulation of water through Carlson Marsh in the dry season, and to drain ponded water after a storm event. Water supplied to the northern portion of Carlson Marsh will be distributed throughout the marsh through a system of weirs, culverts, and low flow channels. Weirs and culverts will be constructed to collect water in the northeastern portion of the marsh. During the dry season, polished creek water will be introduced at the northern portion of the marsh and conveyed through the low flow channels to the southern portion of the marsh. Water will be recirculated to the northernmost seasonal pond via the proposed weir and culvert and will not pass through the culvert under Campus Drive (to UCNRS). The circulation of water in the marsh during the summer will achieve the project objectives of promoting vector control and restoring historic hydrologic conditions. The circulation of water in the summer will also provide permanent open water habitats for resident and migratory wildlife. The weirs and culverts will be similar in design and operation to the existing structures in the marsh.

Contact Information
Gregory K. Herr
Irvine Ranch Water District
Lead/Public Agency
P.O. Box 57000
Irvine, CA 92619-7000

Phone : (949) 453-5577


Cross Streets
Campus Drive and Carlson Drive
Total Acres
State Highways
John Wane
San Diego Creek

Notice of Determination

Approving Agency
Irvine Ranch Water District
Approving Agency Role
Lead Agency
Approved On
Final Environmental Document Available at


(1) The project will have a significant impact on the environment
(2a) An Environmental Impact Report was prepared for this project pursuant to the provisions of CEQA
(2b) A Mitigated or a Negative Declaration was prepared for this project pursuant to the provisions of CEQA
(2c) An other document type was prepared for this project pursuant to the provisions of CEQA
(3) Mitigated measures were made a condition of the approval of the project
(4) A mitigation reporting or monitoring plan was adopted for this project
(5) A Statement of Overriding Considerations was adopted for this project
(6) Findings were made pursuant to the provisions of CEQA

Disclaimer: The document was originally posted before CEQAnet had the capability to host attachments for the public. To obtain the original attachments for this document, 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.

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