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IX

Foreword

Jean Rodier devoted his professional life to tropical regions and developing countries. He was a forerunner to morę than one title. One year after his death on 1 May 1994, the 1 lth Journees Hydrologiques de l’Orstom gave us the opportunity to pay him homage by organizing in Paris from 3 to 4 May 1995 an international conference dedicated to his memory. The title chosen for this conference was «Uhydrologie tropicale: geoscience et outil pour le developpement (tropical hydrology: a geoscience and a tool for sustainability) » reflecting perfectly what was the framework and the objective of Jean Rodier’s work. The principal papers presented at this conference are brought together in this publication.

At a time when water is a major challenge in the relationships between societies, this book demonstrates the interest of scientific specialists concerned with the tropical world, who are concerned with the improvement of knowledge and the methods and techniąues, allowing these to be applied in the developing countries of the tropical belt.

There was a temptation to draw up a balance sheet of what had been Jean Rodier’s and his students activities. But we chose, while recalling his approach and teachings (whose heirs we are); to consider the State of the art and the prospects, surę that Jean Rodier would not have disagreed.

This book is therefore organized in five parts:

—    The first part entitled « Remembering tropical hydrology », recalls (Pouyaud) the main scientific and institutional approaches of Jean Rodier, then tries to synthesize the evolution of the scientific thrust of Orstom in this field, on the one hand the study of smali watersheds (Chevallier & Rodier), where Jean Rodier had played a significant part, on the other hand, the multidisciplinary approach with pedologists, illustrated by the example of the Brazilian Nordeste (Cadier et al.), and, finally, the operational techniąues of acąuisition and monitoring of hydrological data using satellites (Callede & Gautier).

—    The second part, entitled « Rainfall and clunate in tropical milieu », presents knowledge collected using traditional techniąues (L’Hóte et al., Sow), then the results of modern large scalę experiments (Lebel et al.) and statistical studies reąuiring the processing of huge amounts of data (Paturel et al.). Ali these articles focus on large climatic variability that has appeared during the last 15 years with the decreasing rainfall in West Africa.

—    The third part, « Tropical hydrological regimes », brings together papers on the subject of Jean Rodier’s thesis namely the hydrological regimes in black Africa. A first group of articles deals with dry regions: first a generał description given by WMO (Askew & Rodda) then two studies dealing with non-perennial