Environmental Impact Statement - Sonoma Land Trust

California Department of Fish and Game
U.S. Fish and Wildlife Service
Chapter 2. Alternatives
• provide public recreation access south and possibly north of Highway 37;
• enhance 40 acres of non-tidal seasonal wetland north of Highway 37; and
• create 15.5 acres of additional breeding habitat for the California red-legged
frog, including 0.586 acres of excavation in the floodplain near the northern
project boundary.
Figure 2-1 shows an overview of the Project. Figure 2-2 shows a more detailed
view of the components proposed for the diked baylands portions of the project
site and the wetlandsCalifornia red-legged frog (CRLF) enhancement area north
of Highway 37. Actions associated with restoring each component to its
intended state, as identified in the FPRP and modified in response to subsequent
public comments and more recent analyses, are also described in accompanying
text. Project design is being coordinated with MSMVCD to develop strategies to
reduce site suitability for mosquito breeding; with SMART, NCRA, and PUC for
any project elements within the railroad right of way (ROW); and with Caltrans
for any construction adjacent to Highway 37 in the Caltrans ROW.
As part of the project design process, SLT is retaining qualified professionals to
conduct site-specific geotechnical investigations consistent with all applicable
standards and the current standard of care for professional geologic and
geotechnical engineering practice. The purpose of the investigations is to provide
the geotechnical basis for the development of appropriate project design. These
investigations include bedrock and Quaternary geology; geologic structure,
primary and secondary seismic hazards as defined by the State of California;
soils; landslide, liquefaction, and expansive soils hazards; earthwork
recommendations; substrate and foundation design for all project features;
engineering properties of materials used in levee construction; and any other
topics required to provide the geotechnical basis for the design.
The following sections summarize the major restoration components of the
Project. For convenience, these are separated by geographic segment (i.e., south
of railroad, railroad to Highway 37, and north of Highway 37).
South of Railroad—Tidal Marsh
New Levees
Sears Point Wetland and Watershed Restoration
Project Final Environmental Impact
Report/Environmental Impact Statement
A levee with a design height of +12 feet (ft) North American vertical datum of
1988 (NAVD) and an initial top elevation of +13 12 to +14 15.8 feet NAVD
would be constructed south of and parallel to the SMART rail line to separate the
nontidal and tidal habitats.(Note: the levee would be constructed to elevations
above the design height as necessary to account for settlement.) The levee
structure would be constructed entirely outside of the SMART rail line right of
way. The levee would consist of three parts: a “core” levee, geotechnical stability
toe berms, and erosion berms or protection/habitat bermsslopes. These
components are described in more detail below. Conceptual levee designs are
shown in Figure 2-3.
2-6
April 2012