A 1200-mm concrete pipe 1830 m long carries 1.4 m³ from reservoir A, discharging into two concrete pipes each 1370 m long and 750 mm in diameter. One of the 750 mm pipes discharges into reservoir B, in which the water surface is 6.5m lower than that in A. Determine the elevation of the water surface in reservoir C, into which the other 750 mm pipe discharges. Use n = 0.015