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<br />774 JULY 1977
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<br />The only significant modifications are sheet piling vertical retaining ...
<br />the upstream end and at the channel third point. These walls are requi!ieI
<br />bank stabilization because of the closeness of railroad tracks. The rip&'
<br />channel wall, to be constructed of vertically placed sheet piling, was
<br />to provide adequate entrance width for passing river flood flows, and_
<br />alinement that would parallel flood flows moving in the river charmd
<br />9). It was located so as to provide a whitewater channel width of ...
<br />than 25 ft (7.6 m), nor greater than 40 ft (12.2 m). The left river bank
<br />only minimal trimming to provide the 2: I slopes along the channel...
<br />desired for reducing wave reflections and water surface surging, and for
<br />Similar slopes were built inside the right wall for a considerable di...
<br />the same reasons. The channel floor was flat concrete, level tmnsvenelr.
<br />variably sloping downriver. l'
<br />Berms, humps, and wave-producing floor bumps were of standardized
<br />for economy (Fig. 5) and were designed to always present smoothly
<br />surfaces to the water and to any impinging boats or people. Slopes of
<br />were used so that placement and shaping of the concrete facings were pm .
<br />while still keeping the size of each structure within reason. Placement 01
<br />berms and other obstructions was determined by trial and error, startiot
<br />the upstream end of the channel and working downstream. Criteria to be
<br />included adequate flow depths for safety in case of upsets, good currents
<br />eddies for greatest enjoyment and utilization of the recreation facility
<br />velocities not so great as to prevent reasonably competent paddlers from"
<br />back upstream, and eddy placements to facilitate paddling upstream.
<br />considered was use of the channel for slalom racing on an intermediate
<br />use of the channel by all other means of boating and floating (such as
<br />tire tubes), and the necessity of providing good boating at flows ranging
<br />150 cfs-320 cfs (4.2 m' / s-9 10' / s). The final alinement meets these CriteriL .
<br />Initially, the standardized berms and conical humps were 4.5 ft (1.4 m) .
<br />Testing showed they were too low to properly control the larger flows
<br />were sometimes overriden. A better arrangement was to maintain the
<br />at lhe 4.5-ft (I.4,m) height and slope the berms upward toward the c
<br />sides to heights of 5.2 1t-5.7 ft (1.6 m-1.7 m). The conical humps were mi
<br />to a 5.5-ft (I.7-m) height. The floor bumps were I ft (0.3 m) high.
<br />Maximum Flow Velocltles.-Maximum flow velocities at 200 cfs and 320
<br />flows (5.6 m'/s and 9 m'/s) were 11.9 fps and 13.8 fps (3.6 m/s and 4
<br />m/s). These maximum velocities were found near the water surface (not
<br />depth) althe downstream end of the channel. '
<br />Channel Exlt,-A relatively abrupt, I-ft (O.3-m) drop occurs at the end
<br />the white>>:ater c.hannel w~ere it empties into the South Platte River. It is prob
<br />that scounng WIll occur In the river bottom at this point and that a pool
<br />develop and more or less stabilize. The ..ft drop, combined with the n
<br />downward slope of the riverbed, makes possible the addition of more white
<br />channel if funds become available in the future. The maximum velocity in
<br />channel of 13.8 fps (4.2 m/s) occurred at this drop.
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<br />CoNct.ulllONS \
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<br />As a result of these I :20 scale model studies, a practical, safe, and challen .
<br />whitewater recreational boating chute design was developed for the propo
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<br />,. j WHITEWATER C;ANNEL 775
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<br />". the Plalle River in Denver. The design is site-specific and not directly
<br />"""b to other sites or situations. Nevertheless, many of the design concepts
<br />~ ",ay have wide application, and at the least will provide a basis from
<br />10 st~rt studies of similar facilities. [n all cases, it is highly recommended
<br />lIOdel! studies be made of any proposed chutes before determining final
<br />. It I is further recommended that the sludy team include a person or
<br />skilled in whitewater boating, so maximum attention will be given to
<br />. eddies, drops, and flow velocities, to proper interaction of these faclors
<br />Ie best possible recreational facility, and to safety aspects of the system.
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<br />e,1\iese mOdel studies, including most of the design concept development and
<br />. Jl:lUaI conslruction of the model components, were carried out through
<br />r labor and expertise. The United States Bureau of Reclamation made
<br />ble. al no cost, space and facilities for the model studies atlheir Denver,
<br />.. Hydraulic Laboratory. Materials costs for the model were borne by the
<br />ee. design firm. McCall, Ellingson, and Morrill, [nc., Denver, Colo. Principal
<br />en and investigators were the writers and Ron Mason. Mason, an architect
<br />nationally-ranked kayaker was advisor to the engineering firm and was
<br />sible for recognizing at an early date that model studies were needed
<br />*developing a satisfactory whitewater channel. Geoffrey Taylor coordinated
<br />s between the investigators and the engineering firm. Additional valuable
<br />. ance was provided during the studies by Ben Harding, Joan Irwin, Tom
<br />'!ch. Bill Clark, Ulrich Martins, and many other members of the Colorado
<br />. e Waler Association. Photography was by Deane Hall, Robert Pauline,
<br />Wilbourn Batts. Special thanks are given to Albin Sirtautas who obtained
<br />bao from Herr Bartel of Augsburg, Germany. the detailed model test records
<br />the Augsburg, Germany, 1972 Olympic whitewaler chute.
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<br />.-REFERENCE
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<br />"'Canoe Slalom" (Kanuslalom Augsburg), Report No. 22m2. Hydraulic Research
<br />Facility, M.A.N, Gustavsburg. Germany, July, 1970 (in German).
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