Description

The Hamilton Levee was originally designed and built to provide flood protection to approximately 130 acres of existing and proposed development at Hamilton Field. The low-lying areas behind the levee include some properties that are up to two feet below sea level. The levee, at one time called the NHP Levee, is an earthen fill structure or embankment approximately 1.4 miles in length that was constructed in 1997 by the New Hamilton Partnership (NHP). The levee embankment is an integral part of Hamilton Levee “System” which is comprised of the embankment, a concrete masonry splash wall, a splash wall closure gate, two storm water pump stations, and an interior drainage network.

The City of Novato’s CIP Project Number 00-013 raised the crown of the levee by approximately 3.5 feet in 2007. The levee crown was raised to account for the future anticipated settlement while maintaining 100-year flood protection. In addition, the splash wall was raised approximately 4 feet.

On April 25, 2014, an outer levee that held back the waters of San Pablo Bay was breached as part of the adjacent Hamilton Wetlands Restoration Project (HWRP). As of this breach, the levee system directly protects residential subdivisions, park and recreation facilities, museums, businesses, the U.S. Coast Guard Pacific Strike Team, and the associated public right of way improvements from San Pablo Bay.

 Photos above courtesy of Hamilton resident David Brewer

Photo of Installation Rendering

Levee Fencing

Over the years, the City has received periodic concerns about the public utilizing the maintenance access road on the neighborhood side of the levee splashwall for recreation purposes rather than the Bay Trail on the bayward side of the splashwall as intended. In early-2020, concerns increased as more pedestrians began to use the maintenance access road for recreation purposes. In response, City staff in April 2020 deployed temporary metal barricades at four locations where the public could easily gain access to the maintenance access road. To implement a longer-term solution, staff looked to inexpensive, low-visual impact fencing options to replace the temporary barricades. The proposed fence locations, style of fence, and an installation rendering are shown below:

Photo of Proposed Fencing Locations

The decision to install fencing at the six locations shown above was made after reviewing the boundaries of the Public Access Easement along the levee, the Hamilton Levee Operations & Maintenance Manual, the Hamilton Field CC&Rs, and general information previously made available to the public: 

• When the Hamilton Levee was surcharged in the mid-2000s and the Bay Trail was created on the bayward side of the splashwall, a Public Access Easement was granted by the City of Novato to the Bay Conservation Development Commission for the establishment of the Bay Trail along the levee.  Following the construction of the Bay Trail, signs were posted along the maintenance access road on the neighborhood side of the splashwall to direct the public to the Bay Trail. 
• The City’s Hamilton Levee Operations & Maintenance Manual was adopted by the Novato City Council and submitted to FEMA as a part of the levee accreditation process in 2015.  Section 6.1, Vegetation Management, states, “Consistent grass cover is one of the most effective and economical means of protecting the levee embankment against erosion caused by rain runoff and trespassers.  The grass cover requires periodic mowing and possible spot repairs/re-seeding as needed. In addition, every effort must be made to prevent unauthorized encroachments, dumping of yard waste, the misuse of chemicals, or pedestrian/pet traffic.”  There are a few isolated areas of minor erosion on the levee embankment due to unauthorized public access—While three or four of these instances does not compromise the integrity of the levee, uncontrolled public access to the maintenance road could become a problem in the future.
• The Hamilton Field CC&Rs, Section 7.9, states, “In any instance where rear yard fencing is located adjacent to the slope of a levee, there shall be no gate or access opening in the portion of the fence which is adjacent to the slope of the levee.”  The Flood Protection section on this webpage supports the CC&Rs by stating, “It is important for property owners located on the immediate land side of the levee system to understand their role and the City’s responsibilities related to the levee system. Homeowners located adjacent to the perimeter of the levee have a unique obligation to do the following: Be aware of signs of localized seepage; Properly handle and dispose of yard waste and other debris; Properly inspect and maintain yard area drains; Use only designated access points to the SF Bay Trail.”  
•  City staff periodically uses heavy equipment to maintain the levee.  We are proud of our good safety record at the Hamilton Levee and pump stations and would like to keep it that way.

Project Overview & Cost

The proposed fencing installation is limited to isolated locations perpendicular to the levee where it is expected to be effective in guiding the public to the Bay Trail, rather than full perimeter fencing. The type of fencing proposed is just over four feet tall and fencing materials are intended to closely match existing fencing between the wetlands and the Bay Trail to preserve the views. Swing gates will be installed along the maintenance access road at each fence location to facilitate the movement of maintenance equipment such as trucks and mowers.  Wildlife gaps will be left in the fencing so that animals do not find themselves trapped in an enclosed area. 

The fencing and sign installation work is intended to be self-performed by Novato Public Works Department staff.  Materials costs are expected to be approximately $5,000 and funding for the work will come from the Public Works Department operating budget—not the Hamilton Community Facilities District (“CFD” or “Mello-Roos”) budget.  The work is anticipated to be completed by the end of June 2021.

Comments and questions should be directed to pw@novato.org or (415) 899-8246.

Photo of Fence Style

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