Draft Environmental Impact Report - California Off Highway Vehicle ...

3.7 Geology and Soils
types of soils can cause differential movement (shrinking or swelling) and damage to overlying
structures. However, Soils Guideline 1.4 in the General Plan requires that recommendations
contained in the geotechnical investigation addressing site grading, foundations, and other surface
improvements be followed when facilities are constructed, including the headquarters facilities, to
minimize or eliminate risks associated with expansive soils. In addition, development of facilities
envisioned in the General Plan would adhere to all regulatory requirements, such as the CBC,
related to soil safety.
Because construction of facilities would include implementation of measures that would minimize
or eliminate risks associated with expansive soils, this impact would be less than significant.
Mitigation Measures: No mitigation is required.
IMPACT
3.7-5
Wastewater Disposal Incompatibility with Impervious Soils at the SVRA Visitor Facilities
Percolation test results indicate that soils on‐site generally have very slow infiltration properties,
which could make them incompatible with the use of typical septic systems. However, under the
General Plan, sanitary facilities constructed for visitors would consist of vault toilets, which would
not require on‐site septic disposal. (See Impact 3.9‐6 below for discussion of wastewater disposal
at the headquarters facilities.) Therefore, this impact would be less than significant.
Mitigation Measures: No mitigation is required.
Headquarters Facilities Impact Analysis
The impact analyses described above under “General Plan Impact Analysis” address potential
impacts related to all aspects of the General Plan, including constructing and operating the
headquarters facilities. The discussions of risk from geologic instability (Impact 3.7‐1), seismic
ground shaking (Impact 3.7‐2), erosion (Impact 3.7‐3), and expansive soils (Impact 3.7‐4) related
to the construction and operation of facilities envisioned in the General Plan are also applicable to
construction and operation of the headquarters facilities alone; therefore, no additional analysis
related to the headquarters facilities is necessary.
The following analysis addresses a potential impact specific to the operation of the headquarters
facilities alone. Wastewater disposal would be handled differently at the headquarters facilities
than in the rest of the SVRA; a septic system would be used for the headquarters facilities while
vault toilets would be used throughout the rest of the SVRA.
IMPACT
3.7-6
Wastewater Disposal Incompatibility with Impervious Soils at the Headquarters Facilities
Clay Pit State Vehicular Recreation Area
February 2012 3.7-8 Draft EIR