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Hole Number Depth Description <br /> (feet) <br /> RG-12-1 150 • Install inclinometer and 2 vibrating wire piezometers(VWP) <br /> • Investigate reservoir rim block slide <br /> • Core hole with telelogger _ <br /> RG-12-2 150 • Install inclinometer and 1 VWP <br /> • Investigate left abutment rock slide <br /> • ODEX hammer hole;blow counts with telelogger <br /> RG-12-3 120 • Install 1 VWP <br /> • Investigate bypass tunnel and water level in right abutment; <br /> core hole <br /> RG-12-4 30 _ ■ Investigate outlet discharge structure foundation <br /> B-12-1 through B-12-4 15 • Clay borrow-auger from barge <br /> B-12-5 through B-12-9 15 • Investigate clay borrow west of existing reservoir waterline <br /> in reservoir bottom <br /> TP-1 through TP-6 10 to 15 • Dig test pits west of existing reservoir water line for clay <br /> borrow <br /> TP-7 through TP-12 10 to 15 • Dig test pits along northeast shoreline in area of proposed <br /> clay blanket <br /> Four vibrating wire piezometers(VWP)will be installed in the new borings and install four VWPs in the <br /> existing piezometers,which will allow for continuous digital collection of the data. D&A will install two <br /> additional inclinometers and perform a baseline inclinometer survey and two follow-up surveys on all three. <br /> The land based borings will be drilled with a truck-mounted(or"mud-buggy")type rig to allow for access in <br /> difficult terrain. <br /> One deep boring will be used to investigate the block slide northwest of the dam. One deep boring will <br /> investigate the left abutment rock slide. The third deep boring will be drilled in the right abutment rock in <br /> the area of the proposed bypass tunnel. Select borings will be Packer tested for permeability evaluation. <br /> Two of the borings will be logged by Colog with a televiewer. D&A will also investigate the proposed outlet <br /> structure foundation with a boring. <br /> A source of clay borrow for clay blanket construction is needed. It is expected that clay may be obtained <br /> from the reservoir floor. It appears that the landslide on the left abutment dammed a natural lake at the same <br /> location as the current dam, and based on the flat valley bottom topography it probably existed for several <br /> thousand years. Thus, it is expected that natural lake bed clays in the reservoir bottom will be found. <br /> D&A will drill four auger borings from a barge to confirm the presence of clay. D&A will also drill five <br /> auger borings on land upstream of the water line when the reservoir is at gage height 50 or below. D&A will <br /> excavate about 12 test pits using a large track-mounted excavator. Half of the pits will be excavated <br /> upstream of gage height 50 water level to look for clay. The other test pits will be excavated along the <br /> shoreline in the rock slide mass of the left abutment where the clay blanket is to be constructed. <br /> D&A will also evaluate the spillway concrete by taking a few short core holes of the slab and walls. If <br /> possible,D&A will try to obtain core of concrete in the gate structure for testing of unconfined compressive <br /> strength. <br /> Samples obtained from the exploratory drilling and test pits will be tested in the laboratory. Laboratory <br /> testing will be designed to provide information for designing the clay blanket, bypass tunnel,and outlet <br /> discharge structure foundation. Laboratory testing will include: moisture/density,Atterberg limits, -200 <br /> sieve,gradations,pin-hole dispersivity,triaxial shear tests,direct shear tests,and unconfined compressive <br /> strength tests. The test results will develop parameters to be used in the subsequent design analysis. <br /> - 4 - <br />