“…Automatic water level control in open channels remains a challenge for researchers and engineers, as demonstrated by an abundant literature (see, e.g., Cantoni, Weyer, Li, Ooi, Mareels & Ryan (2007); Dang Van Mien (1999); Dumur, Libaux & Boucher (2001); Georges & Litrico (2002); de Halleux, Prieur, Coron, d'Andréa-Novel, Bastin, (2003); Litrico & Fromion (2009); Rabbani, Dorchies, Malaterre, Bayen & Litrico (2009); Thomassin, Bastogne & Richard (2009); Zhuan & Xia (2007)). The excellent review by Zhuan & Xia (2007), which is devoted to channel flow control methodologies, insists on the inherent complexity of this type of problems.…”