Sea Ranch Sanitation Zone Central Treatment Plant Creek Crossing Project


SCH Number
Public Agency
Sonoma County Water Agency
Document Title
Sea Ranch Sanitation Zone Central Treatment Plant Creek Crossing Project
Document Type
NOE - Notice of Exemption
Document Description
The Sonoma County Water Agency owns and manages the Sea Ranch Sanitation Zone Central Treatment Plant, which provides wastewater treatment for a portion of The Sea Ranch community. The Central Treatment Plant collection system includes 1.9 miles of sewer pipelines and one lift station. The gravity sewer serves approximately 50 homes, and traverses open land from the end of White Fir Wood Road, an aerial pipeline crossing over an unnamed creek, and discharges to the headworks of the Central Treatment Plant. The aerial pipeline crossing is an 8-inch diameter pipe within a 14-inch diameter steel casing mounted on two pipe support piers (aerial crossing). In October 2022, a severe weather event caused a tree to fall on the crossing, causing damage to the aerial pipeline casing In addition, the two aerial crossings, constructed in the 1970s, have severe corrosion and are at risk of failure. The project will replace the existing aerial pipeline crossing with a new aerial crossing and two crossing pipe support piers within 20 feet of the existing crossing. Construction activities include removal of: a) the corroded pipe support piers (cut at the ground and abandon in place); b) the existing aerial crossing; removal of an existing manhole (abandon in place), and c) concrete and wood abutment structures. The ends of the 8-inch pipeline will be plugged during construction and a temporary bypass pipeline will be installed. At the end of constructing the new aerial pipeline crossing, the plugs would be removed and the existing 8-inch pipeline will be connected to the new aerial crossing. Portions of the excavated area will be backfilled with Control Low Strength Material.

Contact Information

Connie Barton
Agency Name
Sonoma County Water Agency
Job Title
Senior Environmental Specialist
Contact Types
Lead/Public Agency / Project Applicant


Northern California, Unincorporated
Other Location Info
37875 Highway 1. East of the intersection of Highway 1 and Wild Iris Road, Sonoma County, California, 94597

Notice of Exemption

Exempt Status
Categorical Exemption
Type, Section or Code
15301(b),15302(c), and 21080.21
Reasons for Exemption
The Project consists of replacing an existing facility that involves no expansion of use. The new aerial crossing would be located on the same site as the structure replaced and will have substantially the same purpose and capacity as the existing structure and is less than one mile in length.
County Clerk


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