Inverted Sewer Siphon Replacement

2 Documents in Project


SCH Number
Lead Agency
City of Atascadero
Document Title
Inverted Sewer Siphon Replacement
Document Type
NOD - Notice of Determination
Present Land Use
Atascadero Creek / Open Space / Open Space

Document Description
An inverted sewer siphon crossing, owned and operated by the City of Atascadero, crossed under Atascadero Creek near Lewis Avenue but has become exposed due to erosion and downcutting within the creek channel. The City is concerned that further erosion may weaken the structural supports for the siphon and risk a pipeline failure that could result in untreated sewage entering the creek. The proposed project would be conducted in two phases. Phase 1 would involve constructing a new inverted sewer line. Approximately 450 feet of 8-inch and 16-inch diameter high density polyethylene (HDPE) pipe would be installed approximately 15 to 35 feet under the creek bed using directional drilling equipment. After the new pipelines have been installed and connected to the existing sewer system, the exposed portion of the existing inverted siphon would be removed from the creek using a crane and other equipment. The existing siphon line would be cleaned out and capped prior to removal. This project is necessary to prevent potential an accidental release of sewage into Atascadero Creek which could have serious environmental and health effects. The California Department of Fish and Game is executing a Lake and Streambed Alteration Agreement Number 1600-2004-0852-3 pursuant to Section 1602 of the Fish and Game Code to the project operator, Mr. Mark Marwort / City of Atascadero.

Contact Information
Mike Hill
California Department of Fish and Game
Lead/Public Agency
P.O. Box 47
Yountville, CA 94599

Phone : (805) 489-7355


San Luis Obispo
Cross Streets
East Mall / Lewis Avenue
State Highways
US 101
Lewis Avenue ES
Atascadero Creek, Salinas River

Notice of Determination

Approving Agency
California Department of Fish and Game
Approving Agency Role
Responsible Agency
Approved On
Final Environmental Document Available at
City of Atascadero 6905 El Camino Real Atascadero, CA 93422


(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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