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I I I I I I I I I I I I I I I I I I I Geotechnical Engineering Investigation within 7 days and within the core in 13 days. The piezometer responses relative to the two dye migration tests indicate that peak velocities, e.g. largest fracture apertures, are near the highest gauge heights recorded. Flow times at peak reservoir level were 2.5 hours and 1 hour and 50 minutes respectively for the two tests perfonned. Attempts to plug the seepage intake zones were made by the staff of Santa Maria Reservoir Company. Bentonite, cement and straw were used. At the same time, the reservoir was lowered to gauge height 60.5 feet. These actions resulted in the draining of the upper seepage zones. Testing and observations throughout July and August confinned that the seeps progressively dry up as the reservoir water level drops. It should be noted that Hydro-Triad reported that the abutment piezometer, CA-I, dried up on July 13th at gauge level 65.4 feet. The piezometer, CE-2, located in the core dried up on July 17th at gauge height 62 feet. Examination of Hydro- Triad's graph summarizing piezometer monitoring between May 30 and August 2, 1993 indicates a rise in water level of2.5 feet in CA-l and 3 feet in CE-2 when the reservoir was raised from elevation 10,261 (61 gauge height) to 10,268 feet (68 gauge height). CA-l did not show any change in water level until the reservoir reached approximately 10,265 feet, while CE-2 responded at a reservoir level of 10,266.8 feet. This suggests that there is a zone of higher penneability in the fractured left abutment rock at about elevation 10,265 feet. CA-I showed fluctuations in its water level between 10,265 and 10,267 feet, then showed a steady increase as the reservoir level reached 10,268 feet. When the reservoir levels started dropping below 10,268 feet, piezometer CA-I did not show any rapid change in its water elevations below 10,258 feet. The water level in CA-l stayed at El. 10,258 feet even though its base is at 10,251.8 feet. Water levels in CE-2 stabilized at elevation 10,251 when the reservoir elevation was lowered to 10,264 feet. When the reservoir was lowered from elevation 10,269 to 10,267 feet, the CA-I water level dropped one and one-half foot. Then CA-l did not show any further response and stabilized at El. 10,258 feet even though the reservoir further dropped from 10,267 to 10,251 feet. CE-2 did not show any response to reservoir elevations when the reservoir was lowered below elevation 10,264 feet. It should be noted that the base ofCA-l is 10,251.8 and CE-2 is 10,247 feet, However they maintained a constant water level elevation of 10,258 and 10,251 feet, respectively. Hydro- Triad's monitoring data is included in Appendix E. It appears that the seep and damp areas in the downstream shell of Continental Dam starts to rise above the toe of the dam as the reservoir level rises above 10,260 feet. As the reservoir level reaches gauge levels of 65 feet the seepage velocity increases and is measured in hours. Continental Dam Page 4