What is the normal and critical depth in a rectangular, concrete-lined channel, with b=2 m wide, X= 0.001 m/m, and Q= 1 m3/s? Assume a spillway is to be placed in this channel and the spillway will raise the flow depth 0.15 m. How far upstream will flow depth be equal the normal depth (backwater curve). The backwater curve must be presented in form of Excel spreadsheet and graphically showing the water-surface-profile-computation and the energy grade line. To compute the water-surface-profile use a value of the 1 cm of difference between Δx depths.