Chapter 3 - Natural Resources - Marine Corps Base Camp Pendleton

MCB Camp Pendleton, California
consequently confront species with new competitors, predators and parasites. The
proliferation of invasive species is also predicted. While animals will shift to new suitable
habitats relatively rapidly, plant species are anticipated to shift much slower, if at all,
potentially leading to permanent loss of many plants, which many animal species are
currently dependent for their lifecycles (DOD 2010).
3.1.2. Topography
Camp Pendleton lies on the coastal plains at the southern end of the Santa Ana Mountains,
within the Peninsular Range of southwestern California. The massive Peninsular Range
completes the coastal mountain system of California, extending south from the Los
Angeles Basin to the tip of the Baja Peninsula, and includes the steep, narrow, and
northwest trending San Jacinto, Santa Rosa, Agua Tibia, and Laguna Mountains that
plunge into the Coachella and Imperial Valleys.
The terrain of the Base is varied and includes sandy shores, seaside cliffs, coastal plains,
rolling hills, canyons, and mountains rising to elevations of nearly 2,700 feet. Two major
physiographic provinces occur on Base: coastal plains, which rise steeply from the coast
inland into fairly level terraces, and the rolling foothills of the Santa Margarita Mountains.
The break between these two provinces occurs generally along Basilone Road.
Characteristic of the Peninsular Range, natural erosion over time has formed a series of
southwest trending stream valleys across the generally northwest-trending hills and
mountains. Each stream has developed its own valley fill deposits, including an alluvial fan
at its mouth near the coastline. The marine terraces, inland from the coast, slope uniformly
to the southwest at inclinations of 5% or less with the majority of the rest of the Base
exceeding 15% slope.
Part of the coastal area consists of steep, low-hills known as the San Onofre Hills, which
are dissected by the major stream systems of the Base. The highest elevation of the range is
1,720 feet, atop San Onofre Mountain. Other areas contain low, wave-cut terraces that have
distinct cliffs or escarpments along the seaward edge.
East of the San Onofre Hills is gently rolling topography with soils deep and level enough
to support some agriculture. They give rise to the Santa Margarita Mountains, part of the
Peninsular Range that extends from Orange
and Riverside counties to the Mexican border.
Margarita Peak, at 3,189 feet, is just east of the
Base and about ten miles inland from the
coast.
FIGURE 3-1.
BASE BEACH ACCESS
(PHOTO SOURCE: CAMP PENDLETON)
3.1.3. Geology and Soils
Camp Pendleton contains diverse geological
units, ranging from the oldest metavolcanic
rocks and granite of the southern California
Batholith, to stream- or ocean-cut terrace
sequences and recent alluvium. In general, the
Base is underlain by Holocene to late
3-2 Chapter 3 – Natural Resources