The Haute-Comoé watershed in southwest Burkina Faso is characterized by water resources used for irrigated agriculture, among other things. The water resources of the Haute-Comoé watershed consist mainly of the waters of the Comoé River and its tributaries. Over time, pressure on the basin’s water resources has increased due to the expansion of irrigated agricultural areas. With a view to preventing conflicts over the use of water resources, this study was carried out to examine the evolution, over nearly 40 years, of irrigated agricultural areas within market gardening areas. Market gardening is one of the fastest-growing components of irrigated agriculture, particularly since the promotion of small-scale private irrigation launched by the Burkina Faso government in the early 2000s. To achieve the study’s objective, a method based on the processing of a series of satellite images was adopted. The method used consists in classifying a series of images acquired on anniversary dates, but consecutively 7 to 15 years apart (1986, 2001, 2015 and 2023). On the basis of agronomic expertise, a post-classification phase, based on an analysis of the temporal trajectory of classified pixels, was carried out in order to correct certain unlikely pixel trajectories. Results were evaluated by measuring overall accuracy and the Kappa coefficient. Overall accuracies ranged from 72.57% to 81.90% (for the classification phase) and from 88.25% to 92.50% (for the post-classification phase). At the end of the image post-classification phase, a change detection analysis, i.e. a measurement of the intensity of change (spatial variations) within the classes considered, was carried out, making it possible to assess changes in terrain over time, and to identify categories and levels of transition between classes. The study showed that irrigated areas increased by 25% between 1986 and 2023 in the study area.
The droughts of the 1970s and 1980s led the government of Burkina Faso to secure water resources and agricultural production by building large reservoirs and irrigation schemes. In the early 2000s, this policy of securing water resources was pursued through small-scale village irrigation, which involved developing irrigated agricultural areas around small to medium-sized reservoirs. This study presents the case of water management in a hydro-agricultural area located in Mogtedo (Burkina Faso), with a view to proposing optimisation solutions. The study was based mainly on a literature review and the use of the database of the Irrigation Development Support Programme (2011-2016) in Burkina Faso, with a view to assessing the extent to which agricultural water needs are being met. Analysis of water management in the study area revealed organisational and structural shortcomings within the organisations in charge of water management. It also shows that there is a precarious balance between water supply and demand. This balance is threatened by an unfavourable climatic outlook, which could result in a considerable deficit in the reservoir’s capacity to meet the needs of multiple uses. In order to delay the occurrence of such a collapse, solutions have been proposed, in particular, to improve in particular the efficiency of the use of agricultural water and to better protect the water reservoir against sedimentation.