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Depth of flow <br />The specific dimensions of the U- structure are tailored by the designer to create the <br />desired in stream features. One of the most important variables that is controlled is the depth. <br />The depth is described by the weir equation, which can be expressed as, <br />Q = CLh' .5 <br />(1) <br />where C is an empirically determined constant, L is the river width as defined in the analysis <br />section and h is the height of the flow. The weir equation can be used to determine the <br />approximate depth of the flow in the specific channels. Note that this Equation is an <br />approximation and does not represent an exact relationship. The actual depth at the top of the <br />structure can vary due to a number of variables such as upstream current velocity, roughness of <br />the riverbed or variances in the structures geometry. <br />For the Gunnison project the depth in the low flow channel was set to be 2.2 feet of <br />depth at 250 cfs. At 2000 cfs the depth is an additional 2.5 feet of depth. <br />The depth of the river channel between the offset double deflectors is also tailored to <br />provide navigable flow at minim flows and exciting features at higher flows. In the ODDS <br />the flow velocity is expected to increase from average velocities due to the constriction of the <br />channel. <br />The expected flow velocities can be roughly calculated by assuming even channel depth <br />throughout the reach and using the hydraulic equations. <br />The depth of the water plays a significant role in the variety of uses for a particular <br />channel. A course that is between 1 and 2 feet of depth is navigable. A river -craft draws less <br />than 6 inches of water and paddle strokes typically sink to a depth of approximately two feet. <br />At low flows the Gunnison course is good for basic kayaking. The drops are navigable and <br />provide a good venue for learning the sport of kayaking, but do not represent a significant <br />17 <br />