HomeMy WebLinkAbout[Untitled]_3-58Mr. Yam Haing
2612 Buck Owens Blvd LLC
January 25, 2013 - Page 3
Quaternary Older Alluvium: The middle to lower Pleistocene (Bartow, J.A., 1984, Geologic Map and
Cross Sections of the Southeastern San Joaquin Valley, California, USGS Map 1- 1496), Older Alluvium is
a flat -lying terrace deposit approximately 5 to 10 feet thick that overlies the erosional surface of the
Kern River Formation. The Older Alluvium is composed of very coarse material, with boulders as large as
50 cm in diameter. Clastic material composition includes granitic and dioritic crystalline rocks
characteristic of the Sierra Nevada batholiths, quartzite characteristic of pre- batholithic rocks, and volcanic
and related rocks such as andesite and dark siliceous agate typical of Neogene deposits of the
Mojave Desert. In some locations, caliche rims have developed between clasts.
Kern River Formation: The age of the Kern River Formation includes upper Miocene and Pliocene, and
possibly Pleistocene. The Kern River Formation is composed of interstratified fanglomeratic deposits and
silty claystones. Within the fanglomerates are conglomerate beds with cobbles as large as 20 cm in
diameter, and in some areas fanglomerate beds exhibit cross bedding from 2.5 to 5 meters thick.
The silty claystone beds, which would serve as low - permeability barriers to vertical migration, are laterally
continuous to as much as several thousand feet, but are locally truncated by sandy fanglomerate units.
Another important factor in considering the potential for migration is the lack of secondary permeability
within the Kern River Formation as no secondary cracks, small faults, or gypsum veins are observed.
Chanac Formation: The Chanac Formation of upper Miocene age is not exposed on or near the site, but
outcrops in the cliffs southeast of the site along the Kern River bluffs at Hart Park. It is a thinly bedded,
chalky siltstone exhibiting many secondary cracks and gypsum veins.
HYDROGEOLOGY
The site is located in the southern portion of the Great Valley geomorphic province. The Great Valley is a
north- south - trending valley, approximately 400 miles long by 50 miles wide, the southern portion of which
is known as the San Joaquin Valley. Surface water and groundwater in the San Joaquin Valley are
derived predominantly from the Sierra Nevada to the east and are transported by five major rivers, the
closest to the site being the Kern River. The subject site is located approximately 500 feet north of the
Kern River. The site is constructed within an area where ruble from the 1952 Bakersfield earthquake was
used to fill a seasonal flood zone along the northern flank of the Kern River. The depth to the regional,
unconfined aquifer is less than 50 fbg, and the groundwater gradient is to the west. Perched groundwater
at depths as shallow as 20 fbg flanks the course of the Kern River and may seasonally extend to beneath
the subject site. There are several municipal water supply wells located within a mile of the site.
The groundwater is considered to be potable and suitable for beneficial use.