Search

In the municipality of Mogtedo and Zam, climatic conditions are unfavorable and influence the availability of water resources. Thus, water resources are becoming increasingly valuable for human activities, particularly market gardening and pastoral production. Indeed, the dam located in the village of Talembika in the municipality of Zam and the agricultural plain in Mogtedo are threatened by advanced siltation of the watercourse. This has an impact on the standard of living of the local populations. Can the cause of the silting be linked to a lack of communication on the management of water reservoirs? The main objective is to analyze the perceptions of the users of the dam on silting and the contribution of communication in the process of a good farming technique around the water reservoir of Mogtedo-Zam in the province of Ganzourgou in the Central Plateau region. To do this, quantitative and qualitative methods were used for the collection, processing and analysis of data using appropriate tools. The results of the study reveal rapid siltation of the dam, which is confirmed by 86.96% of the respondents. This situation is due to soil erosion, the deposition of solid materials from the watershed, high pressure from users, and low rainfall. Thus, communication is an important factor in the fight against siltation. The technical services are the first communicators of the users of the dam. Users lack information and awareness on the management of the dam and good farming practices to avoid its rapid siltation.

RésuméLa forêt classée de Tiogo (FCT) connait une gestion centralisée de l’État. L’objectif de l’article est d’évaluer l’impact des activités anthropiques sur la dynamique spatiale de la FCT, dans un contexte de gestion centralisée assurée par l’État. La recherche a tablé sur une revue de la littérature et utilisé des imageries satellitaires de 1992, 2002 et 2018, des enquêtes individuelles, des entretiens de groupes cibles et des observations terrain. L’analyse diachronique de 1992 à 2018 a révélé une diminution continue des superficies de savanes arborées (-49%) et arbustives (-15) au profit des champs (+27%), des zones nues (+5%), des plans d’eau (+3%), des formations ripicoles (1,5%) et des sites d’orpaillages (+1%). La FCT connait une dégradation et une déforestation importantes imputables à la mauvaise gouvernance qui a favorisé l’occupation anarchique des agriculteurs, des éleveurs et surtout des orpailleurs.Mots clés : Dynamique spatiale, occupation des terres, gouvernance, forêt classée de Tiogo, Burkina FasoAbstract: The Tiogo Classified Forest (FCT) is under centralized state management. The objective of the article is to assess the impact of anthropogenic activities on the spatial dynamics of the FCT, in a context of centralized management provided by the State. The research relied on a literature review and used satellite imagery from 1992, 2002 and 2018, individual surveys, focus group interviews and field observations. The diachronic analysis from 1992 to 2018 revealed a continuous decrease in the areas of wooded (-49%) and shrubby (-15%) savannas in favor of fields (+27%), bare areas (+5%), water (+3%), riparian formations (1.5%) and gold panning sites (+1%). The FCT is experiencing significant degradation and deforestation attributable to poor governance, which has favored the anarchic occupation of farmers, breeders and especially gold miners.Keywords: Spatial dynamic, land use, governance, Tiogo Classified Forest, Burkina Faso

Over the last few decades, small-scale irrigation has been implemented in Burkina Faso as a strategy to mitigate the impacts of adverse climate conditions. However, the development of irrigated perimeters around small and medium water reservoirs has put the water resources under significant pressure, given the uncontrolled exploitation and lack of efficacious management plan. Insights into changes in irrigated areas around these reservoirs are therefore crucial for their sustainable management while meeting the different agricultural water needs. They will help to center policy priorities in terms of major impacts on the reservoirs; and thereby elaborate relevant mitigation and/or adaptation strategies. The main objectives of this study were to (1) quantify the changes in irrigated land areas surrounding the Mogtedo water reservoir between 1987 and 2015; and (2) determine whether the irrigable potential of this reservoir could sustainably meet the agricultural water needs under a more variable and changing climate. A low-cost remote sensing method based on Landsat imagery (Thematic Mapper, Enhanced Thematic Mapper Plus, and Operational Land Imager) and using Support Vector Machine (SVM) classification was developed to detect the changes in proportion of land use/land cover (LULC) in the Mogtedo region. A forward and backward change detection analysis requiring agronomic expertise was also applied to correct the pixels temporal trajectories. In addition, an intensity analysis was performed to assess land changes at time intervals, category, and transition levels. Five main LULC classes were identified: bare and hydromorphic soils, irrigated and rainfed agricultural areas, and water bodies. Overall, the classification of LULC was satisfactory with the overall accuracy and kappa coefficients ranging from 94.22 to 95.60% and 0.92 to 0.94, respectively. Results showed that LULC transformations were faster between 2000 and 2015, compared to the 1987−2000 period. The majority of categories (LULC classes) were active in terms of intensity of change (gain or loss) during the 1987−2000 and 2000−2015 periods, except hydromorphic soils. During these periods, the transition from rainfed agricultural areas to irrigated agricultural areas were targeted and stationary. Our findings revealed a 54% increase in irrigated areas between 1987 and 2015. The reservoir water volume decreased markedly from 9,077,000 m3 to 7,100,000 m3 during the same period. Such a decrease threatens the satisfaction of agricultural water requirements, since the reservoir is the unique source of irrigation water in the region. It could potentially lead to conflicts between users if adequate strategies for the sustainable management of the Mogtedo reservoir are not implemented. The methodology used in this study also addressed the challenge of building up historical spatial information database in data-scarce environments, and could be replicated readily in regions or countries like Burkina Faso.