Engenharia de Sistemas de Irrigação e Drenagem

Failure of Inland Valleys Development: A Hydrological Diagnosis of the Bankandi Valley in Burkina Faso

Abstract

Yacouba Y, Aymar BY, Amadou K, Louis FJ, Georges S, Thomas YB, Mouhamed I and Bruno L

Several developed inland valleys for rice production were abandoned due to poor design or implementation. The Bankandi Inland Valley (BIV) is a contour bunds system developed in 2006 by a development project, currently experiencing a systematic waterlogging.
This study assessed:
i. The waterlogging vs. changing hydro-climatic conditions relationship;
ii. The hydrological design and implementation of water control infrastructures; and
iii. How digital elevation models (DEMs) data could be used for inland valleys development.
To investigate the waterlogging vs. changing hydro-climatic conditions (precipitation and discharge), the conceptual HBV model was applied; coupled with break and trend detections tests. To evaluate the accuracy of the location of drainage flume and contour bunds, a topographic survey using a D-GPS was performed. To explore free DEMs as support tool in the development of inland valley, the Shuttle Radar Topography Mission 1 and the Advanced Spaceborne Thermal Emission and Reflection Radiometer 1, were used.
The results show that:
i. the waterlogging was not related to changing environmental conditions;
ii. major flaws including bunds not implemented on contour lines contribute to the waterlogging;
iii. free DEMs were not accurate enough for valley development.
The overall diagnostic of BIV entails conducting basic hydrological investigations prior to implementation.