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PART 5 SPECIFIC TASKS 5. SPECIFIC TASKS: 5.1. Basic Services. The Contractor shall provide services for drilling,groundwater grab sampling,installation of two groundwater monitoring wells,well development,well surface completions,investigative-derived waste management,and written documentation reporting. There are options for standby time,to decommission drilled borings pending groundwater grab sample analytical results,and for the drilling of additional boring/well locations. If either of the two original boring locations indicates E-zone groundwater contamination higher than anticipated,additional well or wells will be installed farther downgradient. Similarly,if either of the two original boring locations indicated E-zone groundwater contamination lower than anticipated,additional well or wells will be installed farther upgradient, closer to the site.Work is described in additional detail and broken out by the following tasks. 5.2. Task 1—Mobilization and Demobilization. Under this task the Contractor is to provide for the mobilization and demobilization of equipment,materials,and personnel to execute under this PWS in Stockton,California. Included under this task are all permitting and records requirements of the State of California(with copies also provided to the Government),any and all associated fees, administrative coordination on technical and contracting matters,Contractor Site Safety and Health Plan development,on-site sani-can portable toilet rental for the duration of the project,and records reporting to the Government both prior to mobilization and at the end of the project. Any contractual costs not explicitly defined under subsequent tasks may be included under Mobilization and Demobilization;however,costs already included under subsequent tasks shall not be duplicated herein. 5.3. Task 2—Drill Subsurface Borings up to 300 Feet Depth. The Contractor shall drill two(2)nominal 8-inch diameter borings with a rotosonic drill rig. Temporary steel casing shall be required to keep the bore hole open and prevent material collapse into the bore hole. Continuous soil samples shall be collected using a sonic soil core barrel advanced inside and ahead of temporary steel casing. The soil samples shall be bagged inside plastic sleeves knotted at the bottom with top and/or bottom depths written in permanent ink on each filled plastic sleeve. Samples should be undisturbed to the maximum extent practicable. The plastic sleeves containing soil samples shall be laid out beside the work area in order of boring advancement depth for easily accessible and orderly logging by the Government geologist or engineer. At no time shall soil core runs exceed 20 feet,and if recovery is less than 100 percent,much shorter core runs are expected in order to improve sample recovery. Soil cuttings,and soil samples after they have been logged by the Government geologist or engineer,obtained during drilling shall be temporarily contained in DOT approved 55-gallon steel drums and transported to a centralized location within the fenced McCormick and Baxter site as designated by the Government. Note: The borings described under Task 2 will be utilized to install wells as described under Task 4,or will be decommissioned as described under optional Task 8 in the unlikely event that wells should not or cannot be installed. 5.4. Task 3—Collect Groundwater Grab Samples from Inside Temporary Cased Borings. Under this task the Contractor shall pause advancement of the borings under Task 2 in order to collect groundwater grab samples of formation water. Grab samples are to be collected at three depths from each boring. The first interval shall correspond to the D-zone aquifer,at a depth of approximately 180 feet,the second interval shall correspond to the E-zone aquifer,at a depth of approximately 275 feet,and the third interval shall also correspond to the E-zone aquifer but at a depth of approximately 300 feet. The on-site Government geologist or engineer will determine the depths at which groundwater samples are to be collected. Groundwater grab samples shall be collected by advancement of a Hydropunch tool or functional equivalent by the Contractor. This type of tool can be