Flow Rate, Q (m3/s), in an open rectangular channel can be predicted using the Manning equation 72 where n Manning roughness coefficient (dimensionless) Ac cross-sectional area of channel [m'] channel slope Im/m R hydraulic radius [mj For a rectangular channel the following estimates can be made where B is the width of the channel bottom [m, and H is the height of the side of the channel [m. (see Figure 2). Figure 2. Sketch of rectangular channel cross-section, with 8width B and height H. Your team discovers that due to constraints out of your control, the bottom of the channel must be B- 10 m, and the slope of the channel S 0.0010. In order to obtain uniform flow along the bottom and sides, your group decides to construct a concrete channel with a float finish. The construction method will only be accurate to 0.5 meter increments, so report your height estimate accordingly. Use the reference table provided to determine the appropriate value to use for Manning's coefficient, [Hint: use the value from the 'Normal column when estimating the parameter, and then take the minimum and maximum into account as error in your estimate of n to see how that might propagate to influence Q, the flow rate.] Manning's n Values Reference tables for Manning's n values for Channels, Closed Conduits Flowing Partially Full, and Corrugated Metal Pipes. Manning's n for Channels (Chow, 1959) Type of Channel and Description Natural streams - minor streams (top width at floodstage