State Route 37 Petaluma River Bridge Preservation Project


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Notice of Availability of a Section 4(f) De Minimis Determination

The California Department of Transportation (Caltrans) has prepared a Section 4(f) De Minimis Determination
for the State Route (SR) 37 Petaluma River Bridge Project in Marin and Sonoma Counties.

What’s being planned: Caltrans has prepared a Section 4(f) De Minimis Determination for the SR 37 Petaluma
River Bridge Project (Project). The Project is located in Marin and Sonoma Counties, California, on SR 37 at post
mile (PM) 14.5 from Harbor Drive to near Sears Point Road. The Project proposes rehabilitation of the bridge
deck, replacement of the bridge fender system, bridge scour protection, and upgrading the bridge railings to meet
current safety standards and maintain the structure in a reliable and serviceable condition.

Why this ad: Caltrans, as the lead agency under the California Environmental Quality Act and the National
Environmental Policy Act, has prepared the Section 4(f) De Minimis Determination to analyze potential effects
the proposed Project may have on Section 4(f) resources, such as parks and recreational facilities within the
Project area. This notice is to inform you of the 30-day public comment period.

Section 4(f) of the U.S. Department of Transportation Act of 1966 seeks to protect publicly owned parks and
recreation areas, wildlife refuges, and historic sites that are eligible for the National Register of Historic Places.
Provisions to carry out this evaluation are recorded in 23 Code of Federal Regulations 774.17, Section 4(f). As part
of the Safe, Accountable and Efficient Transportation Equity Act – A Legacy for Users of 2005, the legislature
established the de minimis finding process, in which determinations are made regarding 4(f) resources when no
adverse effects would occur. De minimis impacts are defined as those that do not adversely affect the activities,
features and attributes for which the property qualifies as a 4(f) resource.

Caltrans has determined that the Project will require the temporary use which would occur on land owned by the
State Lands Commission and leased to and operated by Marin County Parks: the Black Point Boat Launch on the
Marin County side of the Petaluma River. The site is proposed to be temporarily and intermittently used during
construction for parking and loading and unloading activities on barges used to replace the Petaluma River Bridge
fender system and bridge scour mitigation. Although use of the site would intermittently use the boat launch and
adjacent parking lot, this would not restrict the recreational uses of the boat launch and parking lot for public
use. Caltrans has analyzed the use that the Project would have on this Section 4(f) property and has determined
that the Project would have a de minimis use on this Section 4(f) property.

What is available:

The Section 4(f) De Minimis Determination, maps, and Project information are available for review and download

Where you come in:

Comments will be accepted during the minimum 30-day public comment period from November 3, 2022, to
December 2, 2022. Caltrans will address substantive comments in the final Section 4(f) De Minimis Determination.
Comments may be submitted via the website (, or email, or mail to:

Caltrans, District 4
ATTN: Arnica MacCarthy
P.O. Box 23660, MS-8B
Oakland, CA 94623-0660


For more information about this Project, or if you have comments, questions, or concerns please contact Arnica
MacCarthy, Senior Environmental Planner, at or (510) 506-0481. TDD users may
contact the California Relay Service TDD line at 1-800-735-2929 or Voice Line at 1-800-735-2922.