Patterson Valve Exercise 2021 (OM-DFD-2021-027)


SCH Number
Public Agency
California Department of Water Resources (DWR)
Document Title
Patterson Valve Exercise 2021 (OM-DFD-2021-027)
Document Type
NOE - Notice of Exemption
Document Description
DWR Dam Safety Services staff will perform a valve exercise at the Patterson Dam outlet works consisting of a butterfly valve (BFV), a steel conduit, a downstream BFV, and concrete conduit that conveys water to the outlet dissipation structure. The Patterson Dam downstream BFV associated with the low-level outlet shall be exercised by fully opening and closing. To avoid a sudden release of water to the drainage ditch, the steel conduit between both valves will require dewatering. The volume of water between the valves is approximately 881 gallons. The entire project is within the DWR right of way.

Contact Information

Todd Percival
Agency Name
Department of Water Resources
Contact Types
Lead/Public Agency / Parties Undertaking Project

Sara Paiva-Lowry
Agency Name
Department of Water Resources
Contact Types
Lead/Public Agency / Parties Undertaking Project


San Francisco Bay Area
Cross Streets
Patterson Pass and Greenville Road
Other Location Info
Patterson Reservoir. South Bay Aqueduct

Notice of Exemption

Exempt Status
Categorical Exemption
Type, Section or Code
Class 1, Existing Facilities, Section No. 15301(b)
Reasons for Exemption
The State Water Project provides significant and important services to many Californians. This project is exempt because it involves routine maintenance activities. This project will not result in impacts to special status species or habitat. Because this activity can be implemented without any significant environmental impacts, the Categorical Exemption Class 1 will be used for CEQA compliance.
County Clerk


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