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A series of tests were conducted to determine the required placement of the barrier. Figures 41 through 43 show velocities measured for various operating conditions, including river discharges of 240, 811, and 1,450 ft'/s. Three different barrier locations were considered. The tests show that the angle of the velocity vector with the barrier would pin the boats against the barrier unless the barrier extends upstream parallel to the angle of the Englewood primary intakes (recommended barrier location on the figures). For this position, the magnitude of the velocity component perpendicular to the barrier does not exceed 2.5 ftls and the component paralJelto the barrier is larger. This would tend to move the boats downstream parallel to the barrier rather than pinning them against the barrier. Sediment tests. - A typical bedload particle size distribution curve was obtained from WWE for this section of the South Platte River near Oxford Avenue, located approximately 1 mile downstream of Union Avenue. The particle size distribution curve was scaled based on techniques outlined in the Sediment Scaling section of this report. Estimates of bedload discharge rate were made for a large spring flow of 3,000 ft'ls, which has a return period of 10 years (Wright Water Engineers, 1987). The model riverbed was filled with sediment sized according to the gradation determined from the scaling calculations. The bedform was shaped according to cross sections provided by WWE. Templates were used in the model to form the sand according to the field data. Only the area from the main dam to just upstream from the Union Avenue bridge contained sand. Sediment discharge was estimated based on a bedload particle size distribution curve for the South Platte River near Oxford Avenue and river characteristics, including top width, mean depth and velocity, water discharge, water surface slope, and water temperature. These data were entered into a computer program to determine bedload sediment discharge rates using several sediment equations, including Schoklitsch, Kalinske, Meyer-Peter and Muller, and Rottmer. Using the discharge scale ratio (L,2.S), the bedload discharge scaled to 70 poundslhour or an application rate of 17 pounds every 15 minutes in the physical model. At a t10w of 3,000 ft'ls (10-year flood), sediment tests were run with a low wall at radial gate openings of 30 and 100 percent (2.5 and 8 feet). At the 3D-percent opening, a large deposit formed in the Englewood intake area covering the first three water intakes. The sediment was shallower near the upstream end of the intakes, where the flow enters. At the 100-percent radial gate opening, some of the sediment deposit was reduced. However, the first few water intakes were still covered. The sediment test at a riverflow of 3,000 ft'ls was continued for 3 days with the raised solid wall in place along the Englewood intake. Sediment was fed into the model upstream of the Union Avenue bridge every 15 minutes. After 3 days, the deposition in the pool between the Union Avenue dam and the first rockfill dam appeared to be stable. Figures 44 and 45 are photographs of the pool prior to the sediment test. Figures 46 and 47 show contours in the pool before and after the test. A large sand bar was deposited downstream of the main dam to the left of the boatchutes almost to the end of the original stilling basin wall (fig. 48). Another deposit formed downstream of the boatchute in an alluvial fan shape (fig. 49). Downstream from the sluice gate a deposit formed in the submerged sluice area; however, there was no indication of any deposition in the area just 11