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I I I I I I I I I I I I I I I I I ,I il movements were noted on the downstream face of the dam and along the toe. Embankment modifications carried out in 1970 included the construction of a blanket and chimney filter, extension of the outlet pipe in the downstream direction approximately 72 feet, and placement of additional fill to flatten the downstream slope from the original 2:1 (horizontal to vertical) slope to a slope of approximately 4:1. In July, 1971, an area of heavy leakage was located near the right abutment of the main embankment approximately 40 feet downstream of the outlet works. At that time, it was concluded that the seepage was from water passing through the natural, undisturbed ground of the right abutment. The gage height has been restricted to 32 feet since the early 1970's. II Surface water runoff from a severe thunderstorm In 1985 eroded a gulley several feet deep along the left groin of the downstream face, Seepage from the left abutment was noted entering the bottom of the gulley. The gulley was backfilled as soon as conditions permitted. On August 5. 1985. after approximately 45 days of storage near gauge height of 32 feet, a wet area was noted just above the outlet works and extending about 22 feet upstream at the left abutment. At this time, it was concluded that the seepage was the result of water flowing through the left abutment. This water was collecting in the backfilled material placed in the erosion gulley the previous year, instead of being collected in the blanket filter. After development of this wet area. the State Engineer's Office further restricted the gage height to a maximum of 32 feet. with no more than 45 days above gage height 31 feet, and no more than 90 days above gage height 30 feet. Historically, a seepage area has developed at the downstream toe of the embankment between about stations 114+00 and 117+00. The depth of water in the seepage area has been observed to vary with the reservoir level, The depth of water in the seepage area reaches about fIVe feet when the reservoir level is near gage height 31 feet and disappears when the reservoir drops below about gage height 26 feet. Seepage was also noted during the 1980 Inspection by the Corps of Engineers about 300 to 400 feet downstream of the dike portion of the embankment. The seepage was exiting the morainal ridge about 30 to 40 feet below the crest of the dam, There was no evidence that soil particles were being transported by the seepage, 5-2