MODELING AND SIMULATION OF DATA FOR THE IDENTIFICATION AND PREDICTION OF THE BEHAVIOR OF LAKE ALAOTRA IN MAGASCAR

The sustainable management of the Lake Alaotra-Mangoro system, a vital ecological and socio-economic resource in eastern Madagascar, is severely threatenedby rapid anthropogenic pressures and climate change. This study aimed to characterize the complex lacustrine and fluvial dynamics and predict the system'sbehavior to support informed conservation and planning efforts. We employed a rigorous two-dimensional (2D) hydrodynamic modeling approach usingtheInternational River Interface Cooperative (IRIC) software. The model integrated comprehensive topographical, hydrological, and meteorological data to simulateflow behavior over a transient event. The analysis revealed critical insights into the system's vulnerability. Simulation outputs accurately defined areas susceptibleto localized flooding and quantified seasonal water level variations. Hydrodynamic analysis confirmed complex flow interactions, including the concentrationof maximum velocity and depth within the channel's thalweg and the presence of a downstream backwater effect indicated by an inverse water surface elevationgradient. Furthermore, cross-sectional profiles validated the model's ability to capture asymmetrical channel geometry, which is crucial for bank erosionriskassessment. Supporting land-use analysis highlighted significant land degradation and marshland loss, exacerbating the hydrological response. In conclusion, theIRIC model provides robust predictive capability for evaluating the cumulative impacts of environmental change. A primary recommendation is the urgent needto strengthen the local hydrometeorological monitoring network to enhance data quality and model reliability. The findings facilitate the proactive planningof adaptive strategies, including the construction of protective dikes, targeted reforestation, and essential agricultural adjustments, ensuring the long-termresilienceof the Lake Alaotra watershed.

Keywords: Lake Alaotra, Hydrodynamic Modeling, IRIC, Flood Risk, Land Use Change.