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`moi �t j Equipment--Soil borings will be&Iliad with a 7.25-Inch(o.d.)hollow stem continuous flight auger,owned and operated by Osterberg and Stewart,Inc. Soil samples will be collected using 2-inch(o.d.)modif led California split spoon sampler Ilnedwith brass sample tubes. l Boring Logs--Detailed IV will be mads of each boring. The Information noted will include: sample depths,blow counts,horizons of detectable contamination(detected by field methods),soli classification utilizing the Unified Sol]Classification System onq_Mt=t description(color,texture,composition,hardness,moisture content,and post-depositional —VlT9g8_.s'that have occurred in the sediments). Solt Sampling--Soil samples will be collected at 5 foot interva;s to characterize the sediment types and far laboratory analysts. Two to six soil I samples will be analyzed from each mop /wa boring,dependant upon stratigraphy and depth. Brass sample tubes will be sealed with 3 c, aluminum foil,capped,labeled and immediately refrigerated for transport to California Water Labs. Sol?samples not analyzed will be kept refrigerated until project completion. Duplicate Soil Samples--Soil samples will be collected In duplicate,however,,only one sample will be submitted to the laboratory for analysis. The duplicate sample will be kept refrigerated until project completion and will be used only If the necessity should arise. ? ri Sample Screening--Because not every soil sample collected will be analyzed a screenin process Is used to select representative samples. Ths.goal of this select lye process Is to L'" reduce thecostofthe project without compromising'.ehaquality. From fleldobservations noting sediment type,moisture content,and theorre.�anw of contamination odor certain samples can be selected that represent discrete horizons. The presence of contamination barriers can also be detected by this method. .� Boring Abandonment Procedure--Sol I borings wfII be abandoned either by emplacing a bentonite grout(Quik Bel/Benseal mix)using the tremle method,or If a premixed concrete grout Is being used the boring base will be plugged with no less than 6-Inches of bentonite pellets before emplacing the grout to surface. Disposition of Soil Boring Cuttings--Soil cuttings will be containerized In 55-gallon drums until a soil remediation program is implemented. At that time these cuttings will be treated along with the other contaminated sedlmen ts. if a soil remediation program is not required, the cuttings will be dealt with In accordance with the County regulations. Monitoring Weil Design--Monitoring wells will extend 10 to 15 feet into the water table and w I I I be constructed of 2-Inch threaded-joint PVC Alpe(schedule 40)that's perforated from the bottom of the well to 10 feet above the water table. Number 3 sand w I I be used to create a filter pack that extends from the bottom of the well to 2 feet above the perforated zone, A bentonite grout(Quik Gel/Benseal mix)wIII be emplaced above the ffIter pack in the annufar space by using the trem le method. The monitoring well will be secured and a surface seal obtained by cementing in a watertight well box with locking cap. Construction of a typical ho monitoring we]I Is shown In Figure I. ------- ------ ----Monitoring Well Development---Each monitoring well will he developed before a water sample --- - -- Is collected. This will be accomplished by pumping until a clear groundwater Is obtained, Where Time-Endurance sampling procedures are used,ground water will be pumped over a period of several hours with samples being collected periodically throughout the course of pumping. The extracted ground water will be stored in 55-gallon drums until It's determined if the water Is contaminated, Contaminated water will be treated during the, ground water remediation program. Atfer permission is obtained from ft County, uncontaminated water will be released into the city storm drain system. J U 3 .