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<br />DRAFT <br /> <br />for different gate openings between 1/2 foot and 3 feet. The flow over the dam (figs. 9A and 9B) <br />was subtracted from the total inflow to obtain the radial gate flow. Figure 10 shows discharge <br />rating curves for different gate openings. <br /> <br />The Englewood water intake model flow was also calibrated. Row through the Englewood intake <br />was measured volumetrically. The number of turns on a valve controlling the model flow through <br />the intake was related to the water surface elevation (fig. 11). The model was normally operated <br />with the valve open two turns representing 30 ft' Is. This operation was necessary to ensure the <br />correct distribution of flow between the Englewood intake, the sluice, and the flow over the <br />boatchute and dam. Table 1 presents a typical distribution of flows that Englewood takes <br />throughout the year. During the boating season (May-September), Englewood's withdrawal is <br />typically 25 to 30 ft' / s. <br /> <br />Study of Boating Conditions <br /> <br />WWE provided Reclamation with drawings to construct the original boatchute configuratirm in the <br />physical model (figs. 12 and 13). Boatchute 1 was 32 feet wide and the invert elevation was <br />5288 feet. Boatchute 2 downstream was also 32 feet wide and the invert elevation was 5284.5 feet. <br />The effect of the third boatchute on the upstream pool elevations was simulated by incorporating <br />a weir in the downstream end of the model with the proper shape and elevations to simulate <br />boatchute 3. Boatchute 1 curved toward the left to allempt to make the boats approach <br />boatchute 2. Tests were conducted for boating flows ranging between 100 and 3,000 ft' Is. The <br />results of the tests showed that the original boatchute configuration was not satisfac.tory for boating <br />flows. Rafts and kayaks impinged on the right side of the boatchute. Boatchute 2 handled boats <br />beller, but some design changes were also necessary to further improve the flow. <br /> <br />In January 1989, a revised boatchute design was constructed and tested in the physical model. The <br />Union Avenue dam boatchute was 32 feet wide and boatchute 2 was 64 feet wide. Both chutes <br />employed a center trough to concentrate flow for smaller boating flows. An open bar barricade was <br />placed along the Englewood intake (fig. 14) to prevent boaters from entering the sluiceway. The <br />left side of the boatchute was lowered (causing a superelevated chute) to try to force flow to the <br />left. Flows ranging between 100 ft' /s and 1,500 ft' /s were tested in the model. Boats moved toward <br />the sluice wall while passing through the Union Avenue dam boatchute. <br /> <br />Reclamation conducted two demonstrations of the second design configuration. The first <br />demonstration on January 18, 1989, showed the model operating at a range of flows between 100 <br />and 16,400 ft' Is. Allendance at the fust demonstration included personnel from the cities of <br />Englewood, Bowmar, and Sheridan; CWCB; UDFCD (Urban Drainage and Flood Control District); <br />COE; and WWE. <br /> <br />During the fust demonstration, both chutes were narrowed by placing large boulders (5-foot <br />prototype) along each side of the chute to help boating conditions at smaller flows. Photographs <br />of this flow condition are shown on figures 15 and 16. Narrowing the boatchutes improved lower <br />flow conditions, but an undesirable wave still existed downstream of the Union Avenue dam <br />boatchute. The boats had a tendency to turn toward the sluice wall while going through <br />boatchute 1. A high center wave also existed downstream of boatchute 2. <br /> <br />6 <br />