Management of geographic information technology in service of the water erosion's assessment in the eastern part of Antananarivo

• Main Authors: Rakotomalala, Olivier H., Raveloson, Elise, Ramanase, Saraha T. N., Razafindrabe, Frank, Rakotomaria, Etienne
• Format: Conference Proceeding
• Language: English
• Subjects: Accuracy; Digital elevation models; Global Positioning System; Information technology; Photography; Soil; Technology management
• ISSN: 2159-5100

Degradation of watersheds by the phenomenon of erosion has now a great danger for the development of rural areas in Madagascar since on the one hand, the risk of losing a considerable amount of arable soil into rivers is rising and this is irreversible, and on the other hand, the alluvial deposits continue to overrun the agricultural parcels already developed. This paper aims to introduce an assessment methodology with reliable accuracy of the extent of damage caused by water erosion in order to guide the actions of protection and watershed management. This methodology is based on geographic information technology management. Accurate orthophotographies and digital terrain models were established from aerial photography of the study area taken in two different dates. The orthophotography is used to evaluate the surface extent of the phenomena through digitization, the digital terrain model used to evaluate the movement of land through the volumetric calculation. This method has the advantage of being rich in information and can therefore generate other useful products such as the slope map, aspect map,... In conclusion, it is a great decision making tool for the politics as well as developers.