8.42 A 4-ft-diameter cast iron pipeline 4 miles long connects two reservoirs with surface elevations of 500 and 300 ft. It is proposed to increase the flow rate through the line by installing a smooth liner that is just thick enough to cover the roughness elements, reducing the pipe diameter somewhat. Determine the current flow rate and the increase in flow rate using the liner. The water is at 68 F and pipe friction is the dominant loss.