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

5. Environmental Analysis
density in the southern part of San Luis Reservoir (from 50–110 acres per
boat with the other alternatives to 20–50 acres per boat with Alternative 4)
and the eastern part of O’Neill Forebay (from 20–50 acres per boat with
the other alternatives to 10–20 acres per boat with Alternative 4). 9 These
changes in boat density would be partly offset by the three-year phaseout
of nonconformant two-stroke engines; however, short-term, minor adverse
effects could remain.
Dust Emissions Caused by Motorized Vehicles, Construction, or Recreation
Dust and particulate matter in the Plan Area are potentially generated from three
sources: automobile traffic and OHV use on dirt roads and unpaved areas;
nonmotorized recreational trail use, including hiking, horseback riding, and
mountain biking; and grading disturbance from facilities construction. The dust
generated by motor vehicles—including OHVs—driving on dirt roads and
unpaved areas would result in localized minor adverse air quality impacts. Other
recreational trail use such as hiking and horseback riding is not likely to result in
air quality impacts because is not usually fast or intensive enough to create
substantial dust clouds. Other effects of trail erosion are discussed in Section
5.4.1.2 (under Trail and Road Use, Maintenance, and Construction). Site
maintenance and facilities construction that includes ground-disturbing activities
could raise dust and cause minor adverse impacts to air quality.
These effects would vary by alternative as follows:
• Alternative 1, No Action/No Project, would not expand or construct
facilities, roads, or trails, but use of unpaved roads and trails, along with
standard maintenance activities such as trail grading, would continue.
These activities could have minor, short-term adverse effects to air quality,
but to a lesser degree than the action alternatives.
• Alternative 2 proposes some additional features and facilities that could
accommodate or support additional visitors and increase motorized vehicle
travel in unpaved areas (see “Emissions from Motorized Vehicles and
Vessels,” above). These changes could result in minor adverse effects to
air quality that are greater than Alternative 1 but less than Alternatives 3
and 4. Implementation of a trails management plan that incorporates
BMPs to reduce dust could have a beneficial impact on dust emissions that
would not be realized under Alternative 1. With implementation of
measures such as those described in Section 5.4.2.4, any residual impacts
would be minor.
• Alternative 3 would allow for a greater number of features and facilities
that could accommodate or support additional visitors and increase
motorized vehicle travel in unpaved areas (see “Emissions from Motorized
Vehicles and Vessels,” above), compared with Alternative 2. This
alternative would also allow for new trails linking Basalt Use Area with
9 Acres per boat for each WROS zone are described in Sections 4.3.1 through 4.3.3.
San Luis Reservoir SRA 5-21
Draft RMP/GP and Draft EIS/EIR