... notably by Lai (1 965 ), McLaughlin et al. (1 966 ), Amein (1 967 ), Liggett (1 967 , 1 968 ), Evangelisti (1 969 ) and Strelkoff (1970). Following Courant and Friedriechs (1954) and Lai (1 965 ), one converts ... by the amount: steady uniform flow steady non-uniform flow unsteady non-uniform flow 1 2 h +z Q1 Q2 x datum OPEN CHANNEL HYDRAULICS FOR ENGINEERS Chapter 7: UNSTEADY FLOW ... expressions for the continuity equation and the momentum equation are introduced by Sergio Montes (1997) as: OPEN CHANNEL HYDRAULICS FOR ENGINEERS Chapter 7: UNSTEADY FLOW 1 36 Continuity:...