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RESNA This hydrological condition cannot be confirmed by the groundwater monitoring data or observations during excavation If the groundwater elevation data is correct, the direction of the hydraulic gradient changes with the observation date and is not always in a southwesterly direction • Typical historical gradient for this area is to the east ? The PHS/EHD requested a work plan be formulated for soil remediation of the contaminated area on August 26, 1993 A plan was developed to excavate the hydrocarbon contaminated soils near MW 1 to the depth of 1 S' to 20' below the surface Holt Bros prepared a request for proposals on August 11, 1995 and that request was furnished to interested parties All interested parties submitted proposals on September 1, 1995 Foothill Engineering was awarded the contract of soil remediation on September 21, 1995 Work on the project was started on Monday, September 25, 1995 The first order of work was project fencing and concrete removal EXCAVATION OF CONTAMINATED SOILS Excavation was started Tuesday, September 26, 1995 and continued to a depth of 33 feet from the surface At a depth of 32 to 33 feet a very dense layer of impervious clay was encountered Contamination was confined to the soil above the clay layer and all of the contaminated soils encountered were removed to the onsite stockpile area The contaminated soils were located at greater depths than originally anticipated by original excavation studies Contamination was detected by a strong odor to depths of 31 feet Excavation was continued to 33 feet to remove all remaining contaminated soils Excavation was completed using the two bench method The first bench was the original surface and the second bench was at a depth of 14 feet All lower level excavation was completed by the double handling method The Cat 330 excavator made the excavation to 33 feet of depth while positioned on the bench at the 14-foot level and placed the contaminated soil on the surface A Cat 966 rubber tired loader then loaded two 10 wheeler dump trucks for the haul to the stockpile area A small back- hoe was used to clear the truck beds and push up the stockpile The Cat 330 excavator operator required an respirator for some portions of the excavation The volatile portions of the contaminating hydrocarbon was very irritating to the skin and eyes The excavation was measured to determine quantity of soil removed and calculations of the volume were made by the standard DMD method Total volume removed from the excavation was 8,406 cubic yards SIDE WALL AND BOTTOM OF EXCAVATION SOIL TESTING On October 5 & 6, 1995 soil samples were extracted from the sides and bottom of the excavation under the supervision of Ms Margaret Lagono Samples were extracted using a standard hand driven soil sampler into a standard six inch brass BX sample tubes Soil sample tubes were capped with plastic caps with aluminum foil separation between the soil and the cap All samples were marked by both sample number and serial number on tube labels and entered in the database Samples were taken with the aid of a crane and a man cage Test results for the samples are listed in combined form at the end of this report Original soil sample test reports are located under the "TEST RESULTS" section of this report GROUNDWATER REMOVAL FROM EXCAVATION A permit was obtained from the City of Stockton to discharge groundwater into the sanitary sewer 2