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I I I I I I I I I I I I I I I I I I I 5.5 Extending the present 33-inch diameter 320 foot long outlet conduit by 70 feet will not reduce the discharge capacity of the present outlet works. The present outlet conduit slopes down steeply 5.67 feet in 320 f8llt, or 0.0112 feet per foot. The 33-lnch pipe can carry more than 165 cubic feet per second, so the outlet capacity Is limited by the size of the two outlet gates. The present outlet gates appear to be in good condition and will not be replaced. The present outlet works have sufficient capacity to meet downstream water demands. These demands are met even at the restricted reservoir storage levels. The outlet works are more than adequate to maintain restricted storage levels, because of the small size and the drainage area, except in extreme flood conditions. REHABILITATION ALTERNATIVES Rehabilitation alternatives fall into two general categories: Items which need to be performed to upgrade the overall condition of the embankment, and methods for improving the seepage condttions. Rehabilitation measures recommended to upgrade the overall condition of the embankment are shown on Figure 12 and summarized below. . Seepage Collection. To minimize tts detrimental effects, seepage which is currently passing beneath the dike and main embankment should be collected in a filter drain. This filter drain would be constructed along the downstream tow of the embankment and along the discharge channel downstream from the existing energy dlssipator. A toe drain would be constructed along the dike in a trench approximately 4 feet deep underneath the existing downstream toe. The area around the pipe and In the trench would be backfilled with drainage sand. A filter drain would be constructed in the area where seepage is extting In the discharge channel. This would be constructed by extending the outlet works approximately 70 feet In the downstream direction. The downstream slope would be cut back to the original 2:1 (horizontal:vertical) slope, a new blanket and chimney filter drain constructed on the bottom and sides of the excavation, and embankment material placed to flatten the downstream slope to 6: 1 and thereby cover the extended outlet works. This construction would Include demolition of the existing energy disslpator, and construction of a new energy dissipator and riprap-Iined stilling basin. 5-15