Laserfiche WebLink
� Valota Road 5-Lot Residential Development Decer$�B� - Page 123 <br /> � <br /> �r <br /> Tbe closest Type A fault is tbe San A_rzdreas fault located approximately 3.3 rniles �o the <br /> southwest. The closest Type B fauIt is the Monte Vista- �hannon fault located approximateIy 2.1 <br /> miles to the soutk�west of the site. (V+WGCEP, 2007) <br /> 3.0 FIELD INVESTIGATION AND LABORATORY TESTING <br /> Subsurface Explaration <br /> The subsurface expioration consisted of three borings dril�ed at the site on No�rern.ber 23, 2010. <br /> The exploratory borings were drilled under the direction of an ESP staff geologist at the <br /> approximate locations showzl on the Exploratoiy Boring Location Map (Figure 2). The borings <br /> were sarnpled to depths of 10, 15, and 50 feet be�ow the ground surface. The soil was sampled <br /> using a truck-mounted B-53 drilI rig equip�ed with an 8-inch (outside diarrzeter) l�ollow-ste�n <br /> auger and 140 pound drop hammer. The hammer drove a 3 inch (outside diameter} Modified <br /> California sarz�.pler, an.d 2 iz�ch (outside dia�neter) Standard Penetration Sarnpler, 18 inches at a <br /> time as the bozings were advanced. The penetration resistance is described on the bor�ng logs as <br /> the numbex of blows per foot o£penetration. <br /> Soils en.countered �n the bozings were categorized ar�d logged �i.z3 general accordance with the <br /> Unified Soil Classification System. Copies o�the baring logs are incluc�ed in A�pendix A. <br /> Subsurface Prof�le <br /> Based on our exploratory borings at �e site, the site is underlain by alluvial soils to the <br /> rr�a�c.imum depth explored. The borings encountered varying thicknesses of creek bank deposits � <br /> consisting of sa.udy lean clay (CL) and poorly sorted sand (SP} (0 to 5 feet} overlying dark gray <br /> fat clay iz� each of�he barzngs (CH}. The fat clay e�ctended to approximately 9 feet be�ow the <br /> ground surface (bgs). Below 9 feet ouz borings consisted af a mixture of clayey sands (SC) and <br /> sandy clays (CL) witki a well sorted sand (SW} interval from 25 to 32 feet bgs. Clayey silts (N�,} <br /> silty to sar�.dy clays (CL) persisted to 50 feet bgs (the ma�inaum depth explored). <br /> A bleached {elluviated) horizon was encountered from approximately 18 fee� bgs to <br /> approximately 22 feet bgs. T°k�i.s zozae coz�sisted of hard, moist to wet, li�ht gray to wbite clayey <br /> silt. Groundwater was first encountered below this layer at approximately 23 feet bgs and rase�o <br /> approximately 20 feet 6gs at the end of drillin�. Surface water was �resent in the creek c�iannel, <br /> west of the site, however, the channel is concrete lined and �hus the water is isolated frorn the <br /> sun'ounding soil. It sY�ould be noted that fluctuat�ons in the leve� of subsurface water can occur <br /> 3 <br />