Water at 70°f flows by gravity from a large reservoir at a high elevation to a smaller one through a 90-ft-long. 2-in-diameter cast iron piping system that includes four standard flanged elbows, a well-rounded entrance, a sharp-edged exit. and a fully open gate valve. taking the free surface of the lower reservoir as the reference level. determine the elevation 21of the higher reservoir for a flow rate of 10 ft3/min.