Mossbrae Springs Improvements Project
2 Documents in Project
Summary
SCH Number
2022120493
Public Agency
City of Dunsmuir
Document Title
Mossbrae Springs Improvements Project
Document Type
NOE - Notice of Exemption
Received
Posted
9/3/2025
Document Description
The proposed project addresses priority improvements identified in the City’s 2015 Master Water Plan. The City’s water supply is provided through the diversion of a few of the 16 springs that are collectively known as Mossbrae Springs. The remaining springs form Mossbrae Falls, which is directly tributary to the Sacramento River. Water from the springs is of excellent quality and requires no long-term treatment or chlorination at this time; however, emergency chlorination facilities are available adjacent to the spring headworks. The original project included miscellaneous improvements to the City’s water collection system at Mossbrae Springs. In addition, the original project included a new permanent emergency chlorination system located at the Castle Rock Water Bottling facility (APN 059-010-190).
The revised project includes the following proposed improvements at the Springs under a two phases. The chlorination system at the Castle Rock Water Bottling facility would not be installed.
Phase 1 – Mossbrae Springs Emergency Chlorination
• Installation of new emergency chlorination equipment within the existing building and construction of a new chlorination vault on an existing steel water main located at the Springs site. SCADA system improvements would be completed on the existing North Dunsmuir Tank and within the existing emergency chlorination building.
• Addition of 4-inch thick gravel fill along the access pathway.
In addition to the improvements at the Springs, the project includes updates to the existing SCADA system at the North Dunsmuir Tank, including replacement of the existing antenna and modifications to the existing control panel.
Phase 2 – Mossbrae Springs Improvements
• Removal and replacement of the existing parallel 12-inch steel water pipes with a single 18-inch steel pipe in the same alignment;
• Installation of isolation valves, sample taps, and overflow lines to the existing drainage for each spring;
• Replacement of the steel doors on Tunnel 1 and 2 of Spring 2;
• Demolition and replacement of the weir building with a concrete retaining wall and a vault containing flowmeters and piping to maintain the existing hydraulics. Existing culverts would be replaced and a new drain box would be installed adjacent to the vault.
• Construction of a new concrete box around each of the five existing spring boxes. Holes would be cut through the existing stream boxes to connect the steel pipe replacements.
• Addition of 4-inch thick gravel fill along the access pathway.
Contact Information
Name
Dustin Rief
Agency Name
City of Dunsmuir
Job Title
City Manager
Contact Types
Lead/Public Agency / Project Applicant
Phone
Email
Location
Coordinates
Cities
Dunsmuir
Counties
Siskiyou
Regions
Citywide
Cross Streets
Dunsmuir Ave, Siskiyou Ave
Zip
96025
Total Acres
2.9
Parcel #
028-120-180, 030-250-06, 059-010-190, 030-260-400
State Highways
I-5
Railways
Union Pacific
Airports
Dunsmuir Muni-Mott
Schools
Dunsmuir Elementary School
Waterways
Sacramento River, Bear Creek, Hedge Creek
Township
39N
Range
3W, 4W
Section
7, 13
Base
MDM
Notice of Exemption
Exempt Status
Categorical Exemption
Type, Section or Code
California Code of Regulations, Title 14, Division 6, Chapter 3: Class 1, §15301; Class 2, §15302
Reasons for Exemption
Class 1 covers the operation, repair, maintenance, or minor alteration of existing public or private structures, facilities, mechanical equipment, or topographical features, involving negligible or no expansion of existing or former use. Class 2 covers replacement or reconstruction of existing utility systems and/or facilities involving negligible or no expansion of capacity.
The project is consistent with the categorical exemptions noted above because work would consist of repair, maintenance, and minor alterations to existing facilities; no expansion of capacity or change in use would occur.
As documented in the original Notice of Exemption (SCH 2022120493), the proposed project would not have a significant effect on the environment due to unusual circumstances; would not result in damage to scenic resources within a Scenic Highway; is not located on a hazardous waste site pursuant to §65962.5 of the Government Code; would not cause a substantial adverse change in the significance of a historical resource; and would not result in cumulative impacts. The proposed modifications would not change project impacts, and no new potentially significant impacts would occur.
County Clerk
Siskiyou
Attachments
Notice of Exemption
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