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I I I I I I I I I I I I I I I I I I I The location of the holes, pits, and lines are shown in plan on Figure V.2. Interpretive geologic sections are shown on the same figure. logs of the bore holes and test pits, and seismic refraction work sheets are included in Appendix B. The bore holes were drilled with a six-inch diameter hollow stem auger uti1 I zi ng a truck mounted CME-55 rotary drill. Boul ders and bedrock were core drilled with a NX diameter diamond bit using the wire line technique. Standard penetration tests (SPT) were performed and disturbed soil samples were obtained periodically using a splft spoon sampler; Relatively undisturbed soil samples were periodically retrieved using Shelby tubes; Bore hole permeability tests were performed at selected elevations using the fall i ng head and constant head methods. Water pressure tests were performed in the bedrock utilizing a single packer and applying pressure in five ascendi ng and descending stages. Test pi ts were excavated wi th a Cat 225 track mounted backhoe. The machine was equipped with a three-foot wide bucket and had an effective reach of 16 feet. 2.1 .3; 1 Dam Bore hole P-1 was located at the upstream edge of the dam crest, about four feet to the left of the outlet works conduit centerline. The hollow stem auger penetrated 10.0 to 12.0 feet of light brown, slightly silty; sand and gravel, below which the dam was shown to be composed of alternating three- to six-inch thick layers of clean multi-colored coarse sand, medium sand, fine sand, and gravel wi th dark gray to bl ack 1 ayers of c1 ayey sand, ri ch wi th brown spongy organic material, inclUding wood and plant roots. The hole was continuously sampled using the split spoon. At a depth of 54.5 feet; the bore hole contacted the outlet conduit. The hole was cored through the conduit into bedrock at a depth of 60.5 feet, 0.5 feet below the bottom of the outlet conduit. A trace of chemical grout from one of the previous repair efforts was recovered from the split spoon sample taken immediately above the conduit. The bore hole apparently drifted about three feet to the right in order to intersect the outlet conduit near the crown. Water at a rate of approximately five gallons per minute drained out of the dam and into the conduit through the bore hole before it was patched with a mixture of cement, quick-set grout, sand, and bentonite. Water rose up under pressure through the hole in the invert, until it was sealed with the same materials. -45-