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I I I I I I I I I I I I I I I I I I I Nick Ioannides April 13, 1989 Page 2 continued operation. With the solid wall in place the radial gate settings were reduced from 60 percent open to 30 percent open to maintain adequate scouring velocities within the intake channel at 3,000 cfs. It appears that the solid wall lIay 1l11prove intake sediment flushing operations. . 4. The sluice outlet chute downstream of the radial gate remains clear of sediment until the final downstream 40 feet where it fills to the top of the submerged wall. Radial gate operations and the ability to flush sediment will not be affected according to the USSR. 5. A scour hole formed just upstream of the entrance to the boatchute at the existing dam crest where bed material scoured to the bottom of the model. This scour hole had a detrimental effect on the boatchute flow patterns. The bed material used in the model is loose sand whereas COE as-built drawings and field observations indicate the material at the dam is shale bedrock. Geotechnical studies will need to be done to determine if the existing material will resist scour. If not, the design will have to incorporate al'mOring of the upstream entrance to the boatchute. 6. A similar scour situation occurs at the entrance to the Englewood intake channel. Again the prototype bed material is shale bedrock. Similar geotechnical studies need to be performed at this location. 7. The wedge shape of the embankment No.1 crest recommended by Sen Urbonas (UD&FCD) has been modeled and performs adequately. Flow patterns over the crest run parallel to the downstream bank rather than at an angle to the right bank. 8. The downstream boatchute has been modified to the 32 foot template used at the main dam crest. Slight modifications recommended by the USSR were incorporated into this downstream chute. The boating flow patterns were good at the observed 3,000 cfs flow. USSR personnel reports that patterns are good at lower flows. RF/pmt 642-047.0SC (1.55)