Environmental Impact Statement - Sonoma Land Trust

California Department of Fish and Game
U.S. Fish and Wildlife Service
Section 3.1. Geology, Soils, and Paleontology
therefore susceptible to settlement in response to loading. The static loads
imposed on these materials from the construction of these facilities and the
placement of dredged materialssoil and sediment would result in some degree of
ground-surface settlement. Depending on site-specific conditions and the design
of the facilities, the resulting settlement could be fairly uniform, which would
involve relatively uniform settlement over the affected area, or differential, which
would involve unequal settlement over the affected area. Both types of settlement
could affect the structural integrity of proposed facilities and/or reduce the level
of flood protection provided by the levee.
Additionally, since the project includes passive colonization of the restored
wetland area with wetland-specific plant species that exhibit varying tolerances
for exposure to standing water, ground-surface settlement resulting from the
placement of dredged materials could temporarily inhibit the development of
some of the proposed tidal wetland habitats. However, these impacts are
anticipated to be less than significant because the new core levee, geotechnical
stability toe berm, and erosion habitat slopes levees would be designed and
constructed to meet or exceed relevant standards of the U.S. Army Corps of
Engineers (USACE); and any bridges, boardwalks, or undercrossings would be
designed and constructed to meet or exceed ITE’s pedestrian facility standards
and Caltrans’ bikeway and bridge design standards. Furthermore, all facilities
would incorporate any additional recommendations identified in site-specific
geotechnical evaluations completed during detailed design, including provisions
for foundation design. With these measures in place, impacts related to the
settlement of proposed facilities due to the placement of static loads on
compressible substrate materials are considered less than significant, and no
mitigation is required.
Conclusion: Less than Significant.
Full-Tidal Alternative
The potential for the proposed facilities to settle as a result of settlement on
compressible substrate materials would be the same as for the Project. Impacts
are considered less than significant, and no mitigation is required.
Conclusion: Less than Significant.
Impact GEO-3: Potential for Increased Exposure of
Persons or Structures to Landslide Hazards
Proposed Project
The project would include a trail alignment connecting with the Bay Trail to the
east and west, as well as other trail extensions between the SMART rail line and
Highway 37 and north of Highway 37, to the degree funding is available. Upland
areas both north and south of the Highway 37 are characterized by generally
Sears Point Wetland and Watershed Restoration
Project Final Environmental Impact
Report/Environmental Impact Statement
3.1-16
April 2012