Ross Valley
Flood Control Zone 9
Ross Valley
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Watershed Overview

The 28-square mile Corte Madera watershed extends from Mt. Tamalpais and White’s Hill through the communities of Fairfax, Sleepy Hollow, San Anselmo, Ross, Kentfield, Greenbrae, Larkspur, and Corte Madera to San Francisco Bay. The watershed includes 44 miles of stream channels. Ross Creek drains the northern slope of Mt. Tamalpais; San Anselmo Creek and its tributaries drain the northwestern portion of the watershed. The two channels join to form Corte Madera Creek, which continues through more than a mile of concrete-lined channel past the confluences of Larkspur and Tamalpais Creeks and into the salt marsh at the mouth.

Despite the dense development in the valley floors, the Corte Madera watershed supports a great diversity of habitats from redwood forest to serpentine outcrops, chaparral, oak woodlands, grasslands, and tidal wetlands. It is home to many protected species including at least 17 plants, steelhead trout, spotted owls, San Pablo Song Sparrow, California clapper and black rails, and salt marsh harvest mouse. Corte Madera Marsh Ecological Reserve is recognized as an Important Bird Area by the Audubon Society.

In 2006, the County of Marin, City of Larkspur and Towns of Fairfax, Ross and San Anselmo formed the Ross Valley Flood Protection and Watershed Program (RVFPWP) to develop and implement a flood management program that promotes with healthy watershed processes.

Learn more about the history and habitat of the Ross Valley watershed

Events & Meetings

Event Date: Time: Location:

There is no December 2017 Ross Valley Zone 9 Advisory Board meeting scheduled.  Stay tuned for our next meeting in March 2018 tbd.

Thank you!

Event Date: Time: Location:

Interested community members joined staff for a meeting & site tour of

Event Date: Time: Location:

District staff provided a presentation update to the Larkspur City Council on the Program, hydraulic modeling, Lower Corte Madera Creek Improvement Study, creek & rainfall gages, and 2017 creek

Event Date: Time: Location:
Two neighborhood meetings were held with residents and businesses along Sir Francis Drake, Poplar, and Sylvan to discuss conceptual Frederick Allen Park Riparian Corridor and removal of Ross Fish
Event Date: Time: 7:00 P.M. – 9:00 P.M. Location: Larkspur City Hall 400 Magnolia Avenue Larkspur
Event Date: Time: Location:
Event Date: Time: 9:30 am Location: Fairfax Community Center, 16 Park Rd.

Fellow nature enthusiasts joined in clearing out trash & debris, opening up the creek flow, and restoring natural habitat along Fairfax's creeks.

Event Date: Time: 5:00-9:00 PM Location: Ross School Gym at 9 Lagunitas Road, Ross CA

5:00-6:30 PM Workshop for Phoenix Lake IRWM Grant Migration Alternatives
7:00 PM - 9:00 PM Advisory Board Meeting

Event Date: Time: Location:

Staff provided an update to the Ross Town Council on the Phoenix Lake project and options to migrate Prop 1E grant funds to alternative flood prevention options in the Ross Valley.

Event Date: Time: Location: Isabel Cook Community Center

Residents in the Morningside neighborhood in San Anselmo held a community conversation about flooding issues and possible options to address flooding with staff from the County and the

Capital Projects

Maintenance Projects

  • The National Weather Service's Climate Prediction Center anticipates that there will be a strong El Niño this upcoming winter and their latest precipitation outlook for December through March indicates that Marin is likely to receive higher than average amounts of precipitation. Additionally, due in part to warmer than average ocean waters, tides could be significantly higher than predicted.

Ross Valley Flood Protection and Watershed Program

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Felix Meneau - Zone Engineer
Telephone No. (415) 473-3223

Zone 9 was established in 1966 to act as a sponsoring agency for a major U.S. Army Corps of Engineers flood control project on Corte Madera Creek.  The Zone boundary was amended In January 2007 to include all territories within the incorporated areas of the towns of San Anselmo and Fairfax.  This change was undertaken in response to the flood of December 31, 2005 and the subsequent creation of the Ross Valley Flood Control and Watershed program.  

Zone 9 covers over 29 square miles, including the towns of Fairfax, San Anselmo, Ross and Larkspur as well as the unincorporated communities of San Anselmo, Fairfax, Kentfield, and Greenbrae. There are 21,095 parcels in the Zone.

The boundaries of the Zone and the Corte Madera Creek Watershed closely align. Corte Madera Creek is a substantial perennial stream. Tributaries that join the mainstem before it flows into San Francisco Bay include Fairfax, San Anselmo, Ross, Sleepy Hollow, Kittle, and Larkspur Creeks. 

The Zone 9 work program includes regular maintenance of 1 mile of flood protection levees, maintenance of the USACE concrete channel, maintenance of tidegates and trash racks, and an annual vegetation maintenance program along 0.6 mile of creek. Zone 9 periodically dredges lower Corte Madera Creek to remove accumulated sediment and to improve flow conveyance.


Overview of the Ross Valley Flood Protection & Watershed Program

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