Table 1: Approaching flow characteristics qw (m3/s/m) h(m) Uw (m/s) Fr 8 0.4 20 10.1 13 0.6 21.67 8.93 18 0.8 22.5 8.03 24 1 24 7.66 40 1.5 26.67 6.95 56 2 28 6.32 75 2.5 30 6.06