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31 <br />channel flows and can develop a more detailed, multitransect map of <br />the stream environment. <br />s <br />The WSP model employs three basic equations to represent <br />hydraulic dynamics: (1) continuity or conservation of discharge <br />between transects, (2) Manning's Equation (Eq. 2-2), and (3) Bernoulli <br />Energy Equation (Eq. 2-4). <br />H = z + d + v2l2g, (2-4) <br />where H = total energy head (m), <br />z = elevation of the stream bed, <br />d = average depth (m), <br />v = average velocity (m/s), and <br />g = force of gravity on water. <br />These three equations Are used to link transect data together to <br />predict depths and velocities longitudinally through a stream reach <br />(Bovee and Milhous 1978). The Bernoulli Equation is used to calculate <br />the change in energy head between transects and the energy slope, S <br />(change in H per longitudinal distance downstream) that is required in <br />the Manning Equation. A "step-backwater" procedure is used to balance <br />energy losses in an iterative process that predicts water surface <br />elevations beginning at the downstream transect and proceeding <br />upstream. The adaptation of the WSP hydraulic simulation method to <br />instream flow analysis may include an additional step of predicting <br />mean water column velocities for multiple subsections of each <br />transect. The use of the step-backwater procedure to predict velocity <br />distributions is the most significant new aspect of WSP applications <br />and requires careful calibration to assure accuracy (Bovee and Milhous <br />1978): The limitations of this modeling approach are discussed in <br />greater detail in Sect. 3.1.1. <br />r <br />The generation of instream flow recommendations from WSP <br />simulations involves the same type of habitat-discharge curve