Reach 3 Question 3 (30 points) a) Determine the maximum allowable discharge which would not cause erosion in an unlined trapezoidal channel having b = 3y, z = 2, permissible unit tractive force Tp = 12 N/m, n = 0.02, and S, = 0.002. The channel material is slightly rounded non cohesive soil that 25% material by weight is larger than 20 mm. b) Draw the figure of your final design on which all the important parameters indicated. Note that if K0.78 bed shear controls the required depth. Reach 3 Question 3 (30 points) a) Determine the maximum allowable discharge which would not cause erosion in an unlined trapezoidal channel having b = 3y, z = 2, permissible unit tractive force Tp = 12 N/m, n = 0.02, and S, = 0.002. The channel material is slightly rounded non cohesive soil that 25% material by weight is larger than 20 mm. b) Draw the figure of your final design on which all the important parameters indicated. Note that if K0.78 bed shear controls the required depth