Draft EIS/EIR for the San Luis Reservoir SRA Resource ...

5. Environmental Analysis
Area that are currently inaccessible, could affect cultural resources. These effects
would vary by alternative as follows:
• Alternative 1, the No Action/No Project Alternative, would not
accommodate or support additional visitors to the Plan Area. The
continuation of existing visitor uses could have minor adverse to adverse
effects on cultural resources.
• Alternative 2 has some potential to increase visitation by allowing for
improvements or additions to campgrounds and day use facilities.
Recorded prehistoric or historic resources are not known to exist in most
areas where improvements or additions are proposed, although no final
conclusions can be reached about the level of impact to cultural resources
until project footprints are identified and an appropriate level of
archaeological survey is conducted. The addition of 30 tent sites at Los
Banos Creek Use Area included in Alternative 2 and the other action
alternatives could expose two prehistoric housepit sites (CA-Mer-36 and
CA-Mer-37) to increased unauthorized collection and other forms of
disturbance. These sites are inundated at least part of the year. By
including an appropriate level of archaeological survey, development of a
cultural resources management plan, and appropriate measures from
Section 5.4.4.4, adverse impacts from Alternative 2 would be avoided,
although minor impacts could remain. Alternative 2 would have a slightly
greater potential for unauthorized collection or vandalism of cultural
resources than would Alternative 1, but less than from Alternatives 3 and
4.
• Alternative 3 proposes a greater number of features and facilities in the
Plan Area that would accommodate or support increased visitor use than
does Alternative 2. Most would be in areas with no recorded prehistoric or
historic resources, although no final conclusions can be reached about the
level of impact to cultural resources until project footprints are identified
and an appropriate level of archaeological survey is conducted. This
alternative would have the same potential impacts listed for Alternative 2.
In addition, the proposed multi-use trail linking Basalt Use Area with
Pacheco State Park could expose eight documented prehistoric sites (Table
5-3) to new visitation and potential unauthorized collection or vandalism.
Four of the sites are particularly sensitive, as they are typically above the
high-water line of San Luis Reservoir. In addition, trail use has the
potential to affect undocumented historic resources related to the original
site of Rancho San Luis Gonzaga. The original land-grant period ranch
and the Pacheco Adobe were in an area now under the reservoir and dam,
but related structure remains and features could still be present. Although
not formally surveyed or recorded, the Rancho San Luis Gonzaga site
could constitute a significant cultural resource, and any related facility
remains or features disturbed by visitation or other Plan Area activities
would constitute a significant impact.
5-42 San Luis Reservoir SRA
Draft RMP/GP and Draft EIS/EIR