WSPC12472 - Laserfiche WebLink

Home Browse Search

002501 Depth of flow The specific dimensions of the V-structure are tailored by the designer to create the desired in stream features. One of the most important variables that is controlled is' the depth. The depth is described by the weir equation, which can be expressed as, Q = CLhJ.5 (1) where C is an empirically determined constant, L is the river width as defmed in the analysis section and h is the height of the flow. The weir equation can be used to determine the approximate depth of the flow in the specific 'channels. Note that this Equation is an approximation and does not represent an exact relationship. The actual depth at the top of the structure can vary due to a number of variables such as upstream current velocity, roughness of the riverbed or variances in the structures geometry. For the Gunnison project the depth in the low flow channel was set to be 2.2 feet of depth at 250 cfs. At 2000 cfs the depth is an additional 2.5 feet of depth. The depth of the river channel between the offset double deflectors is also tailored to provide navigable flow at minimum flows and exciting features at higher flows. In the ODDs the flow velocity is ,expected to increase from average velocities due to the constriction of the channel. The expected flow velocities can be roughly, calculated by assummg even channel depth throughout the reach and using the hydraulic equations. The depth of the water plays a significant role in the variety of uses for a particular channel. A course that is between 1 and 2 feet of depth is navigable. A river-craft draws less than 6 inches of water and paddle strokes typically sink to a depth of approximately two feet. At low flows the Gunnison course is good for basic kayaking. The drops are navigable and provide a good venue for learning the sport of kayaking, but do not represent a significant 17