Background: The change in land use has increased flood risk in Tunisia.
Objective: This paper evaluates the impact of such changes on the Mellegue River basin in Tunisia.
Method: The semi-distributed (Hydrologiska Byråns Vattenbalansavdelning) HBV-Light hydrological
model and remote sensing for two different periods were used in the evaluation. ArcGIS software was
used to generate land use/cover maps. The accuracy of the classified maps was assessed using contingency
Result: The results show that the forest area decreased by 5% from 1988 to 2003 due to anthropogenic
activities. As well, the irrigated land increased by 4% due to development of advanced agricultural
techniques and governmental support to increase agricultural yield. Model calibration and validation using
GAP optimization for land use in 1988 and 2003 gave an efficiency of 0.38 and 0.33, respectively.
The validation results slightly decreased compared to the calibration step.
Conclusion: The paper showed that deforestation was the main factor of increasing the runoff from
1988 to 2003.