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boatchute, but boats did not pass through at low flows without hitting the first ramp. Boats tended to turn sideways as they went over the second ramp. This configuration significantly reduced the wave heights. The next boatchute design configuration constructed in the physical model for boatchute 1 included two ramps with a center trough extending through the first ramp but not through the second ramp (figs. 22 and 23). The elevation of the upper ramp was reduced to 5287.25 feet and the second ramp was increased to 5286.5 feel. Wave patterns were acceptable for boating at 100 ft'ls and 800 ft'/s with a V-wave pattern (figs. 24 and 25); however, the wave in the center was larger than the previous configuration. The boats remained straight as they passed through the chute. A third demonstration was held on March 22, ]989, with personnel attending from Reclamation, WWE, COE, CWCB, UDFCD, GS (Geological Survey), and the city of Englewood. The model was demonstrated for flows between 100 and 8,000 ft'/s. UDFeD proposed a change in the alignment of the second dam and boatchute 2 and reorientation of boatchute 2. Boatchute 2 was directed away from the left bank to prevent development of a scour hole and possible bank erosion. The right side of the second dam was brought up to elevation 5287 to form a wedge shape and prevent erosion along the right bank. Boatchute 2 was reconstructed in the model with the invert elevation at 5284.5 feet (fig. 26). Boatchute 2 contained a center trough through the first ramp (the same as boatchute 1). Wave patterns were excellent with a V-wave forming in the middle of the second ramp. Tests were run on boatchute 2 to determine the optimum elevation of the ramps with respect to the tailwater elevation. The elevation of the weir blade on the end of the model was adjusted to simulate elevation changes at boatchute 3 (not modeled). The final design modification occurred in May 1989 on boatchute 1. Using information obtained from the optimization tests on boatchute 2, the elevation of the first ramp was reduced to 5286.75 feet, and the elevation of the second ramp was reduced to 5286.0 feel. The length of the 10 to 1 slope was increased to accommodate the reduction in elevation of the two ramps (figs. 3- 5). This modification was made to accommodate the larger drop of 3-1/2 feet at boatchute 1. Boatchute 2 drop was 2-1/2 feel. The wave patterns and boating conditions were excellent throughout the boating flows. Final boatchute configuration. - After the final configuration of the boatchute was established, including the low flow notch in the center and the combination of two ramps to disperse the wave, a series of tests was conducted to determine the optimum elevation of the ramps with respect to tailwater elevation. Figure 27 shows the optimum relationship between the ramp elevations on boatchute 1, boatchute 2, and the pool between the two boatchutes. The capacity of the low flow notch in boatchute 2 (elevation 5284.5 to 5286.0) is approximately 30 ft'/s. For flows exceeding 30 ft'/s (including sluice flows), the second ramp in boatchute 1 will be completely submerged. The low flow notch extends through the first ramp; therefore, small boats will be able to pass through the notch at low flows. As the flow increases and the pool rises, the combination of the two ramps spreads the wave while maintaining a V pattern in the center. Without the low flow notch through the first ramp, the wave was uniformly dispersed in the downstream pool and the wave height was reduced. However, boats tended to turn sideways as they went over the second ramp. The low flow notch maintains a V-wave in the center which keeps the boats straight. Pilot rocks placed upstream 8