Environmental Impact Statement - Sonoma Land Trust

California Department of Fish and Game
U.S. Fish and Wildlife Service
Chapter 2. Alternatives
Alternatives Considered but Not Evaluated in Detail
These alternatives were determined to not meet the purpose and need, not be
feasible, or not to provide substantial variation in environmental impacts. These
five alternatives are described below along with the reasons for not considering
them in detail in this document.
Muted-Tidal Alternative
A Muted-Tidal alternative was considered by SLT during the initial project
planning. This alternative includes the same features as the Project for south of
the railroad (tidal marsh) and north of Highway 37 (diked seasonal wetland). For
the diked baylands segment from the railroad to Highway 37, this alternative
includes muted tidal marsh, distinct from the Project (non-tidal) and the Full-
Tidal Alternative.
This alternative would meet the project purpose and need and is considered
feasible. However, this alternative is an intermediate alternative between the
Project and the Full-Tidal Alternative in terms of its wetland outputs. The muted
tidal marsh would have unique environmental impacts and provide a diversity of
habitats, including transitional habitat between upland grasslands, and tidal
marsh. However, the muted tidal alternative would convert some of the best
existing seasonal wetlands habitat found at Sears Point. It would also preclude
any oat hay farming on the property. Once built, the muted tidal marsh would
require regular, long-term maintenance and operations funding. SLT has avoided
developing restoration scenarios where regular and costly maintenance is
required. Consequently, SLT with concurrence from USFWS and CDFG has
pursued the FullTidal Alternative and the Partial Tidal Wetland Alternative
(Proposed Project). Thus, detailed analysis of this alternative, would not
substantively add useful information to the NEPA/CEQA evaluation.
Full Equilibrium Dredging Alternative
This alternative would include dredging of Tolay Creek to its geomorphic
equilibrium width at the outset of the project to provide full tidal exchange in the
early years of wetland formation for the project as well as for the prior Tolay
Creek restoration project. The exact dimensions of the dredging necessary to
reach the approximate equilibrium have not been determined. However, Moffatt-
Nichol, in their hydrodynamic analysis, estimated that even with the most
extensive dredging/widening of Tolay Creek (Scenario 6) there would still be
tidal damping (approximately 6%) compared to existing conditions. This
alternative would include additional dredging beyond that included in Scenario 6
to achieve 100% tidal exchange in Tolay Creek. Dredging would likely involve
further widening and deepening beyond Scenario 6.
Sears Point Wetland and Watershed Restoration
Project Final Environmental Impact
Report/Environmental Impact Statement
2-46
April 2012