A rectangular channel 2.0 m wide carrying a discharge of 2.5 m3/s is to be fitted with a weir at its downstream end to provide a means of flow measurement as well as to cause heading-up of the water surface. Two choices (i) a sharp crested weir plate of 0.80 m high and (ii) a broadcrested weir block of 0.80 m height and 1.0 m width, both spanning the full width of the channel, are considered. Which of these weirs causes a higher heading-up and to what extent?