Routine Maintenance in Arroyo Pasajero (AP) Terminus


SCH Number
Public Agency
California Department of Water Resources (DWR)
Document Title
Routine Maintenance in Arroyo Pasajero (AP) Terminus
Document Type
NOE - Notice of Exemption
Document Description
Routine maintenance of the AP channel enables DWR's AP training dike to safely route flows to the WSDB, which stores floodwaters and sediment which would otherwise threaten the integrity of the Aqueduct. DWR's San Luis Field Division (SLFD) will annually maintain the channel and embankments as needed based on annual rainfall and sediment accumulation. Sediment will be removed from the channel, as needed, to maintain Caltrans’ design specifications and to protect the Aqueduct where necessary. Low-lying areas exist east and west of Lassen Avenue, adjacent to the north side of the AP channel. Collectively, these areas have enough space to contain approximately 90,500 CY of sediment removed from the channel. Sediment deposited in these areas will be compacted and graded in a way that will support the main channel geometry. SLFD will periodically maintain the existing 36-inch diameter culvert located beneath Lassen Avenue north of the main bridge. The culvert captures highway runoff during rain events. Culvert maintenance involves flushing it out with a water truck or by utilizing a Vactor truck. The maintenance frequency will depend on the amount of runoff received annually. Since the completion of Caltrans' State Route 269 project, there is currently no native vegetation in the channel or on the banks. However, should vegetation grow in the future, cutting and mowing will be done with hand tools and heavy equipment followed with herbicide treatment. All vegetation will remain onsite to be burned within the same year of work, when burn permits are acquired. Herbicide application will follow a Herbicide Plan. Depending on the amount of flow, up to 250,000 CY of sediment will be removed or re-graded, annually, in order to clear the channel, reconstruct the embankments, and to maintain the channel depths established by Caltrans and to protect the Aqueduct.

Contact Information

Valerie Clevenger
Agency Name
CA Dept. of Water Resources
Contact Types
Lead/Public Agency


State Highways
Highway 198
Other Location Info
Specific: The AP channel and Westside Detention Basin (WSDB) are about 2 miles north of the City of Huron, 2 miles west of the California Aqueduct (Aqueduct), and 1.5 miles south of Highway 198.

Notice of Exemption

Exempt Status
Categorical Exemption
Type, Section or Code
Sections 15304 and 15301
Reasons for Exemption
The project will maintain the Arroyo Pasajero channel to preserve the current Caltrans' design specifications. The maintenance activities will cause only minor changes in the existing project area; no healthy, mature, scenic trees will be removed. DWR's WSDB is an existing flood control facility. Maintenance work in it will not expand the use of the basin beyond design specifications. Categorical Exemptions 15304 and 15301 apply.


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