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
levee willwould result in less than ½ inch total settlement beneath the existing
railroad tracks. Furthermore, the geotechnical investigation indicates that no
adverse impacts on the existing SMART railroad tracks are expected as a result
of the levee construction.
The proposed levee would be designed and constructed to meet or exceed
relevant standards of the U.S. Army Corps of Engineers and would therefore be
built to an appropriate engineering standard of care. Furthermore, the design of
the levee would incorporate additional recommendations in site-specific
geotechnical evaluations completed during detailed design, which, among other
things, would address issues related to settlement, mudwave creation, and other
site-specific conditions with the potential to adversely affect the rail line. As
such, impacts are considered less than significant, and no mitigation is required.
Conclusion: Less than Significant.
Full-Tidal Alternative
In order to protect the SMART railroad line from flooding, the SMART tracks
would be raised above existing grade on a core levee, with habitat berms slopes
abutting the levee on both sides. Flood control levees would be constructed along
Highway 37 and Reclamation Road. The proposed levees would be designed and
constructed to meet or exceed relevant standards of the U.S. Army Corps of
Engineers and would therefore be built to an appropriate engineering standard of
care, which would ensure the stability of both the core levee and the railroad line
supported by the core levee, as well as the adjacent roads. Furthermore, the
design of the levee would incorporate any additional recommendations identified
in site-specific geotechnical evaluations completed during detailed design. As
such, impacts are considered less than significant, and no mitigation is required.
Conclusion: Less than Significant.
Impact GEO-8: Damage to Paleontological Resources
Proposed Project
The majority of the earthwork associated with site restoration would occur in
locations composed of Bay mud or artificial fill placed over Bay mud. As noted
above, the paleontological sensitivity is low; therefore, potential impacts are
considered less than significant.
Upland portions of the Project site (alluvial fan areas north of Highway 37 and
the upland areas south of Highway 37) are underlain by the Petaluma Formation,
which has yielded numerous fossils, including remains of horse, estuarine
ostracods, fish remains, and thin-shelled mollusks. This formation is therefore
considered highly sensitive for paleontological resources. Limited earthwork
would be required to construct the proposed trail alignments within the Petaluma
Sears Point Wetland and Watershed Restoration
Project Final Environmental Impact
Report/Environmental Impact Statement
3.1-20
April 2012