Fifteen-stage operation of gated spillways for flood routing management through artificial reservoirs

A procedure to identify sets of operational rules for gated spillways for optimal flood routing management of artificial reservoirs is proposed. The flood retention storage of a dam having a gated flood spillway is divided into 15 sub-storages whose surface elevations are identified as critical levels. The most suitable operation set for the downstream conditions and for the dam can be chosen from many derived operation sets. The spillway gates are operated in an optimum way for any floods from very small magnitudes to the probable maximum flood (PMF), without having to forecast the actual magnitude of the incoming flood hydrograph. Decision floods are formed by dividing the PMF into 15 sub-hydrographs by 5 and 10% increments in the ranges 5-50% and 50-100% of the PMF, respectively. Many potential spillway gate openings from closed to fully open are chosen initially. As a result of a series of routing simulations of 15 decision floods, a set of 15 gate openings is determined such that all floods from very small magnitudes to the PMF may be routed without overtopping the dam crest. Next, a few more 15-stage operation rules are determined such that the gate openings of the initial stages are decreased as their critical levels are increased stepwise, with the objective of attenuating smaller floods more effectively and releasing higher outflows for larger floods close to and including the PMF. The developed model is applied to the Catalan and Aslantas dams in Turkey, both of which serve for flood mitigation as well as hydropower generation. Citation Haktanir, T., Citakoglu, H., and Acanal, N., 2013. Fifteen-stage operation of gated spillways for flood routing management through artificial reservoirs. Hydrological Sciences Journal, 58 (5), 1013-1031. Editor Z.W. Kundzewicz; Associate editor A. Montanari Resume On propose une procedure pour identifier des ensembles de regles operationnelles de deversoirs a vannes pour la gestion du transfert des crues dans des reservoirs artificiels. Le volume de retention des crues d'un barrage ayant un evacuateur de crues a vannes est divise en 15 sous-stockages dont les niveaux sont identifies comme des niveaux critiques. L'ensemble de manOEuvres le plus approprie pour les conditions en aval et pour le barrage peut etre choisi parmi de nombreux jeux de manOEuvres possibles. Les vannes de l'evacuateur sont manOEuvrees de maniere optimale pour toute crue, allant d'une crue de tres petite amplitude a la crue maximale probable (CMP), sans avoir a prevoir l'ampleur reelle de l'hydrogramme de crue entrant. Les crues de decision sont produites en divisant la CMP en 15 sous-hydrogrammes par increments de 5 et 10% dans les gammes de 5-50% et 50-100% de la CMP, respectivement. De nombreuses ouvertures potentielles de vannes du deversoir, de la position fermee a completement ouverte, sont choisies au depart. Resultat d'une serie de simulations du transfert de 15 crues de decision, un ensemble de 15 ouvertures de vannes est determine, de telle sorte qu'elles puissent transferer toutes les crues, depuis les crues de tres petite amplitude a la CMP, sans debordement au-dessus de la crete du barrage. Ensuite, quelques regles de manOEuvre a 15 niveaux sont determinees de telle sorte que les ouvertures des vannes des premiers niveaux soient reduites a mesure que leurs niveaux critiques sont augmentes par palier, avec l'objectif d'attenuer plus efficacement les crues de moindre importance et de relacher des debits plus eleves pour les crues plus importantes, proches ou egales a la CMP. Le modele developpe est applique aux barrages Catalan et Aslantas en Turquie, les deux servant a l'ecretement des crues, ainsi qu'a la production d'hydroelectricite. Citation Haktanir, T., Citakoglu, H., and Acanal, N., 2013. Fifteen-stage operation of gated spillways for flood routing management through artificial reservoirs. Hydrological Sciences Journal, 58 (5), 1013-1031. Editor Z.W. Kundzewicz; Associate editor A. Montanari