3 Managing the Combined Hazards of Rainy Season and Flooding in the Absence of Planning: Agriculture in the Flood-Prone Areas of Kilombero and Lower Rufiji (Southern Tanzania)
Résumé
Two regions were identified to address the case of flood-prone, rice-growing areas with low levels of planning: first, the lower Rufiji River Valley in southern Tanzania, and second, the Ifakara region on the Kilombero River, a tributary of the Rufiji (Fig. 3.1). These two small regions offer an excellent opportunity to reflect on how farmers can consider the risks associated with climatic hazards. Farmers are confronted with two types of hazards, both related to climate: first, rainfall volume and distribution (date of the first significant rainfall, distribution of subsequent rains), and second, flood volume and timing (location, duration), on which the areas harvested, effectiveness of fertilization (deposition by the flood), and yields obtained depend. These regions are also part of the development "corridor" advocated by SAGCOT (Southern Agricultural Growth Corridor of Tanzania), where different agricultural models (family farming and large-scale investment projects, including rice cultivation plans) are combined.
Projections of possible rainfall change in East Africa are relatively uncertain and do not make for a very clear trend (Chapter 2, this volume). Although southern Tanzania is one of the regions for which a rainfall increase is considered likely (Kilembe et al., 2012), we will see that recent rainfall trends in the two regions studied call for caution: a clear decrease in rainfall is well documented in the Rufiji River's lower valley, but upstream, in the valley of its tributary, the Kilombero, the trend seems to be more upward (see below). This region of East Africa is also one that would be affected-all the models converge on this point-by an increase in the frequency and intensity of extreme events, particularly floods. The years 1997, 2007, and 2014 bear witness to these extreme events.
Domaines
Sciences de l'Homme et SociétéOrigine | Fichiers produits par l'(les) auteur(s) |
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