An overflow masonry dam is to be constructed across a stream. The stream is estimated to have a maximum flood discharge of 900 m3/s when the elevation of the water surface at the dam site is 345m. Six sluice gates each 2.4m x 1.8m wide (C= 0.75) are to be constructed in the dam with their sill at elevation 342m. The main overflow weir for which C = 1.45 will be 60 m long with a crest elevation of 360m. An Auxiliary weir 180m long with a crest elevation of 361m will operate during the floods. For this weir, C = 1.85. With all sluice gates open and when the discharge is 900m3/s, neglecting velocity of approach, Determine the discharge of the main weir.