Regional hydrological modelling of irrigation and drainage systems : case study in Argentina

Abstract

A proper understanding of the interaction of irrigation and drainage canals with an aquifer system is necessary to improve performance of irrigation. A further complication is that this mechanism must be studied with a detail sufficient to identify operational guidelines for specific portions of an irrigation and drainage system. Numerical simulation models provide a useful support in this respect, since specific operational procedures of irrigation and drainage canals can be evaluated in this way. The objective of this paper is to demonstrate the use of the model SIMGRO in an irrigated area in the Province of Mendoza as a support to decision-making of water management aspects. The regional hydrologic model SIMGRO simulates the water flow in the saturated zone, the unsaturated zone and the surface water. It takes into account the effects of irrigation and drainage systems and its impact on the evapotranspiration of the different land uses. Irrigated by the Lower Tunuyan River, the selected study area was 27,500 ha. It was defined by means of a finite element network consisting of 443 nods and the distance between nodes is of some 1000 metres. The model was run for the 87/88, 88/89 and 89/90 agricultural seasons and measured data were compared with the data calculated by the model. In order to understand how each parameter affects the results of the model and the importance of their accurate measurement, sensitivity analyses were performed. / Pour améliorer le fonctionnement des systèmes d'irrigation il faut une compréhension appropriée de l'interaction entre les canaux d'irrigation et de drainage et le système d'aquifères. Une plus grande difficulté réside dans le fait que ce mécanisme doit être étudié d'une façon suffisamment détaillée pour réussir à identifier des règles opérationnelles pour des secteurs spécifiques d'un système d'arrosage et de drainage. A cet égard les modèles numériques représentent une aide convenable du moment que par ce chemin des procédés opérationnels spécifiques de canaux d'irrigation et de drainage peuvent être évalués