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Depth of flow <br />The specific dimensions of the U- structure are tailored by the designer to create the desired <br />in- stream features. One of the most important variables that is controlled is the depth. The <br />depth is described by the Weir Equation, which can be expressed as, <br />Q = Cbbl.S (1) <br />where C is an empirically determined constant, b 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 <br />the structure can vary due to a number of variables including upstream current velocity and <br />roughness of channel. <br />Approximate dimensions and functionality of U- Structures designed for <br />the Animas River <br />The U- Structures that are specified have not been specifically designed. The design process <br />that will be used will include analysis of the shapes through HEC-RAS to establish that there <br />is no net effect to the floodplain due to the installation of the boating park. This flood <br />model will also provide information with regard to flow depths and velocities throughout the <br />park. At this preliminary stage of the design the Weir Equation can be used to give a general <br />indication of the shapes of the structures. This analysis can be used to establish that a <br />particular amount of constriction is generally appropriate for the existing geometry of the <br />existing riverbed. Site inspection and geometric analysis has indicated that the upper reach <br />of the Smelter Boating Park, due to pre - existing structures and pre - existing constrictions, will <br />allow for deeper, more constricted whitewater structures. In the lower reach, the reach <br />where Structures 10, 11, and 12 are placed, the river is wider and flatter and a less <br />constrictive aspect ratio is appropriate. Figures 12 and 13 show the calculations made to <br />compute flow depths and widths. These calculations were made using the commercially <br />available EXCEL software package. <br />MOZ <br />