A bridge has cylindrical piers 1 m in diameter and spaced 15 m apart. Downstream of the bridge where the flow disturbance from the piers is no longer present, the flow depth is 2.9 m and the mean velocity is 2.5 m/s. (a) Calculate the depth of flow upstream of the bridge assuming that the pier coefficient of drag is 1.2. Drag Force CD ? Af (V1^2)/2 CD=1.2 (b) Determine the head loss caused by the piers.