Chapters 1 - U.S. Fish and Wildlife Service

Environmental Consequences
excavators, motor graders, and dump trucks would be used to achieve the desired elevations and
excess material would be removed to an appropriate offsite location.
The salt marsh restoration sites near Case Road and 7 th Street would be designed and constructed
to include meandering subtidal swales that would extend from the existing edge of the subtidal
habitat through the range of salt marsh zones (i.e., low, middle, and high) that would be created.
The swales would be constructed to include broad side slopes to support increased habitat
diversity.
The sum total of these proposed restoration efforts would be to change the topography and
elevations on approximately 36 acres of the Refuge. These changes would not however be adverse,
as they would not negatively modify a highly scenic area nor would they affect a locally or
regionally important topographic landmark. Neither would the proposed grading substantially
alter the existing landform by creating manufactured slopes higher than ten feet or steeper than
2:1 (50 percent).
Alternative B calls for restoration of salt marsh and wetland/upland transitional habitats at several
sites around the Refuge, the replacement of existing culverts in the Bolsa Cell with a new water
control structure, and the removal of concrete and other debris from the marsh. At present, the
restoration sites, as well as the upland area to the east of 7 th Street Pond, are dominated by nonnative,
invasive upland plants. Conventional land excavators, motor graders, and dump trucks
would be used to achieve the desired elevations in the restored areas. Excess material from the
restoration site, as well as concrete and other debris removed from the marsh, would be removed
to an appropriate offsite location using dump trucks. While grading activities in the restoration
areas are underway, there would be temporary, minor adverse effects to visual quality. However,
once grading has concluded and the sites have had the chance to be restored to native salt marsh
and transitional habitats, visual quality would be improved over the present condition.
No substantive change in the appearance of the levee in the Bolsa Cell would result from the
replacement of the existing culverts with a new water control structure, and removal of the 1,400 to
1,600 metric tons of concrete debris from the marsh would have a beneficial effect. Overall,
Alternative B would have a long-term, beneficial impact on visual resources at the Refuge.
Public Use
No changes to the current public use program are proposed under Alternative B, therefore, as
described under Alternative A above, no impacts to topography or visual quality would result from
the continuation of the limited public use program that is currently conducted on the Refuge.
5.2.2.2 Effects to Geology/Soils
Wildlife and Habitat Management
As noted in the sections above, each of the management activities conducted under Alternative A
would also occur under Alternative B. None of these activities would trigger or accelerate
substantial slope instability, subsidence, ground failure, or erosion, thus affecting onsite facilities
or adjacent facilities, such as roadway embankments and bridge abutments and pilings.
Alternative B proposes to expand existing management activities to include habitat restoration in
several locations within the Refuge. Restoration of salt marsh and wetland/upland transitional
habitats could temporarily expose soil to wind and water erosion if Best Management Practices
(BMPs) are not implemented during construction. To avoid such impacts, all restoration
construction specifications would include the requirement to implement appropriate BMPs for
erosion and sediment control during construction to minimize the potential for water and wind
Draft Comprehensive Conservation Plan 5-13