Hydrography and geomorphology of Antananarivo High City (Madagascar)

ABSTRACT

The city of Antananarivo is located in the central highlands of Madagascar, and is the largest urban center of the island. Considering the frequent heavy cyclonic rains frequently affecting the area, its geomorphological context is particularly prone to geo-hydrological hazards, such as landslides and flash floods, as recently proved during the disastrous events of the winters of 2015 and 2018. Field data and high-resolution remote sensing data interpretation (DEMs and satellite orthophotos) were combined in order to produce detailed hydrographic and geomorphological maps. The aim was to understand the processes acting in the Analamanga hill area, with special regards to the effect of human activity in modeling the natural landforms and exacerbating the geo-hydrological hazards. The obtained maps will provide management-planning tools to be used as a first step towards a risk reduction strategy in the Antananarivo historical urban center.

KEYWORDS:

• Geomorphological mapping
• GIS
• remote sensing
• cultural heritage
• landslides

Acknowledgements

This work was carried out in the framework of the activities of the UNESCO chair on prevention and sustainable management of geo-hydrological hazards of the University of Florence, Italy (www.unesco-geohazards.unifi.it), carried out in cooperation with the Région Île-de-France. The authors would like to thank: Paris Region Expertise-Madagascar (PRX) and in particular Tamara Teisseidre-Philip, Alexandrine Wadel, Coline Mollaret for providing all of the available topographic data, and especially kindness and support during our work; Francois Cristofoli and Filippo De Dominicis (RC Heritage/RCh consultants) for the logistic support and suggestions; Helihanta Rajaonarison of Antananarivo University for her precious knowledge and guidance, Niandr Bania Ramboason and Andria Rou’hrouh for their valuable assistance and enthusiasm.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.