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Worn Spring Road Slide Repairs

Construction Update

Marin Water is working to repair an important access point on the Mount Tamalpais Watershed after historic winter rainfall caused a portion of Worn Spring Road to fail.  The landslide took place on the south side of Worn Spring Road, about 400 feet from Phoenix Lake. Adjacent to the slide location, the District maintains an 18-inch welded steel water transmission main that supplies water to Ross Reservoir, a treated water reservoir that serves as the primary treated water storage facility for District customers in Ross Valley.  The landslide occurred during an historic stretch of winter rainfall that marked the wettest three weeks in 161 years, according to reporting from the Bay Area News Group. Work to repair the rain-damaged roadway involves the installation of a 60-foot soldier pile retaining wall with concrete lagging, as well as a guardrail.

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Road Closures and Other Impacts

Worn Spring Road will be closed three weeks before the start of construction, and throughout the duration of the 100-day construction window, which is scheduled to begin in August. Marin Water will notify residents in the immediate area of the planned work, which is expected to be complete in late October 2023.  

Contact Information

Marin Water Construction Management team: 415-945-1560

Project Worn Spring Road Repairs
Program A1E05 – Watershed – Road Repair and Improvements
Project Number D23017
Contact

Zak Talbott
415-945-1508
ztalbott@marinwater.org

Project Description 

Installation of a new 60-foot soldier pile retaining wall with concrete lagging to stabilize Worn Spring Road which partially failed following storm events in January 2023. Worn Spring Road is the primary access route to Ross Reservoir and the existing 18-inch welded steel water transmission main that supplies water to Ross Reservoir is also located within this road. A guardrail will also be installed during the project.

Benefits

A winter storm on January 11th, 2023, caused a land slide on the outboard side of Worn Spring Road approximately 400 feet from Phoenix Lake. An 18-inch welded steel pipe transmission main is located on the inboard side of Worn Spring Road. This transmission main is critical for the conveyance of treated water from the District’s Bon Tempe Treatment Plant to Ross Reservoir and to the Ross Valley area. Ross Reservoir is the primary treated water storage facility for District customers in Ross Valley and maintaining the pipeline and equipment access to Ross Reservoir will ensure the District is able to provide a reliable source of water for customers within this region.

Schedule and Status

Planning: Winter 2023

Design: Spring 2023

Construction:  Summer - Fall 2023

Expenditure Schedule

Actuals Through 
FY 23 
FY 23 
Estimate 
Total
$56,000
$234,000
$290,000

Funding Sources 

Capital Maintenance Fund 
Other Funding Sources 
Total
$339,000
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$339,000