GABA Olayèmi Ursula Charlène
The objective of this work is to understand how the natural dynamics of a time-varying catchment, i.e. the rainfall pattern, transforms the random component of rainfall and how this transformation influences the river discharge. The thesis presents new hypotheses to go further in the development of the model based on the Physics Principle of Least Action with a view of widening its application in Africa and in the USA. Its performance was compared to two well-known lumped conceptual models, the GR4J and HBV models. The analysis revealed that the three models have similar performance and timing errors. But in contrary to other models used in this study, MODHYMA is subject to a less loss of performance from calibration to validation. In order to explore the possible transferability of our model for ungauged basins studies, we then intended to investigate how model parameters could be estimated from the physical catchments characteristics.