Génèse des débits dans les petits bassins versants ruraux en milieu tempéré : 2 - Modélisation systémique et dynamique

Abstract

SUMMARYThe second part of this review on streamflow génération analyses how the knowledge available from field studies (see Part 1) has been used since the 1960s or could be used to improve catchment modelling. After a présentation of the main mode! types, the various problems encountered during the modelling process are discussed.The large variety of hydrologie models available for event or continuous simulation can be reduced to a few main types according to the ways the functional, spatial and temporal aspects of the catchment behaviour are represented. Lumped "blackbox" models are useful for many engineering problems but can not be used in "extrapolation" and give no information on the internai catchment dynamics. Lumped conceptual models, which consider a catchment as a System of interconnected réservoirs and simulate the main global fluxes, use empirical lumped relationships and parameters that often hâve no great physical meaning and are not measurable. Semi-distributed conceptual models use the same réservoir description, but at the scale of "homogeneous" units derived from a space discrétisation, which allows one to take catchment structure explicitly into account. Physicaliy-based distributed models, which use theoretical équa-tions and measurable parameters, provide a dynamic explanation of catchment behaviour but require too much information and are too complex to be easily used at the catchment scale. Physico-conceptual semi-distributed models try to overcome the limits of the previous types, while keeping their advantages, by simplifying the dynamic approach and discrétisation using new concepts.Physically-based or conceptual models, which describe or explain the water cycle at the catchment scale, are very useful for research, but their use in prac- Correspondance : ambroise@geographie.u-strasbg.fr Partie 1 publiée dans Rev. Sci. Eau 11/4 (1998). Les commentaires seront reçus jusqu'au 30 septembre 1999.

The impact of land use change on soil water holding capacity and river flow modelling in the Nakambe River, Burkina-Faso

“…We use two models to simulate monthly flows: GR2M (Ambroise, 1999) and a standard monthly WBM (Conway, 1997;Conway and Mahé, 2004). Both models use a simple soil moisture accounting procedure where rainfall excess over potential evaporation (PE) fills a soil moisture reservoir (taken as the WHC).…”

An Automatic Optimization Technique for the Calibration of a Physically Based Hydrological Rainfall-Runoff Model

“…The choice of the value should be based on those which can permit the best agreement between simulations and observations [Deraedt, 2011]. It is important to use the series of data which presents the greatest contrast in the values in order to cover the greatest number of river discharge [Ambroise, 1999;Grayson & Blöschl, 2000]. This allows to limit extrapolation at maximum while using the model.…”

Simulation du bilan hydro–sédimentaire d’un barrage collinaire en zone marneuse méditerranéenne (Cas du barrage Saboun, Maroc)

“…Les modèles empiriques, Curve Number (CN), modèles rationnels, hydrogramme unitaire, équations universelles de perte en sol MUSLE et RUSLE (WILLIAMS, 1975) donnent des résultats moyens sur des périodes de longue durée mais ne sont pas fiables pour évaluer l'impact d'une évolution du milieu naturel ou des pratiques culturales sur les régimes hydrologiques. Les modèles distribués à base physique sont de plus en plus nombreux et se veulent être de bons outils de simulation et de prévision (AMBROISE, 1999). Ils sont mis au point et testés sur des bassins versants connus pour lesquels on dispose d'importants jeux de données.…”