Trione-Annadel State Park Lake Ilsanjo Dam No. 1 Outfall Repair Project
Summary
SCH Number
2025070380
Public Agency
California Department of Parks and Recreation
Document Title
Trione-Annadel State Park Lake Ilsanjo Dam No. 1 Outfall Repair Project
Document Type
NOE - Notice of Exemption
Received
Posted
7/10/2025
Document Description
The project proposes to repair the outlet pipe from Dam No. 1 at Lake Ilsanjo in Trione-Annadel State Park to correct deficiencies, improve the structure, and ensure the safety of residents living downstream. The overall scope of work will include grading, installation of on-grade pipe with anchors, installation of a utility vault to house a gate valve, removal of the existing pipe, and installation of rock slope protection.Specifically, work will:
- As needed, grade, place gravel, and/or perform minor modifications to Canyon Trail Road for access to the project site;
- Excavate as needed to remove the existing outfall pipe and concrete vault;
Install an approx. 6-ft x 6-ft x 6-ft precast concrete vault with locking lid and backfill the area behind the vault with soil excavated during the prior removal;
- Downslope of the vault, grade as needed to achieve positive drainage;
- Install an approx. 40-foot-long, 12-in. diameter, steel downpipe;
- Inside the new vault box, use a new steel gate valve to connect the new and existing pipe;
- Excavate to install two (2) reinforced concrete anchors to provide support for the downpipe; and
- Install fabric and rock riprap in a 10-ft x 16-ft area at the base of the downpipe for energy dissipation
Contact Information
Name
Joel Bonilla
Agency Name
California State Parks
Job Title
Environmental Coordinator
Contact Types
Lead/Public Agency
Phone
Location
Coordinates
Counties
Sonoma
Regions
Northern California
Cross Streets
6201 Channel Dr, Santa Rosa, CA 95409
Zip
95409
Other Information
The project within Trione-Annadel State Park. The project footprint is on the Dam face of Lake Ilsanjo Dam, adjacent to the intersection of Lake Trail and Spring Creek Trail.
Notice of Exemption
Exempt Status
Categorical Exemption
Type, Section or Code
Class 1 Section 15301, Class 2 Section 15302, Class 3 Section 15303, and Class 4 Section 15304
Reasons for Exemption
The project consists of the operation, repair, maintenance, or minor alteration of existing public or private structures, facilities, or topographical features, involving negligible or no expansion of use beyond current levels; replacement or reconstruction of existing structures and facilities where the new structure will be located on the same site as the structure replaced and will have substantially the same purpose and capacity as the structure replaced; construction and location of limited numbers of new, small facilities or structures; and minor public or private alterations in the condition of land and/or revegetation which do not involve removal of mature, scenic trees and is included as "Resource management projects" in the Department of Parks and Recreation's list of exempt activities in accordance with CCR Section 15300.4.
Attachments
Notice of Exemption
Disclaimer: The Governor’s Office of Land Use and Climate Innovation (LCI) accepts no responsibility for the content or accessibility of these documents. To obtain an attachment in a different format, please contact the lead agency at the contact information listed above. For more information, please visit LCI’s Accessibility Site.