Water Constraints and Flood-Recession Agriculture in the Senegal River Valley

Mamadou Sall,Didier Martin,Jean-Christophe Poussin,Jean-Claude Bader,Aymar Yaovi Bossa,Madiama Cissé,Ramatoulaye Ndiaye,Andrew Ogilvie,Benjamin Sultan

doi:10.3390/atmos11111192

Abstract

Flood recession farming practiced in flood-prone areas and on the banks of rivers and lakes in arid or semi-arid environments essentially depends on the soil water stock after the flood has receded. During these last few decades, this coveted agriculture is increasingly challenged by severe water constraints, due to increased hydrological hazards and development projects aimed at controlling floods. These challenges are difficult to anticipate, and are the subject of a great deal of uncertainty regarding the sustainability of development projects in the concerned areas. In this study, recent hydraulic data of the Senegal River were analyzed to understand the constraints related to the river management in flood-prone areas. Satellite imagery analysis techniques were used to estimate flooded areas and establish relationships with the river regime. Agricultural practices implemented by farmers were also analyzed to evaluate the resilience of this cropping system to the risk of water stress. The results confirmed many constraints of different importance related to the objectives assigned to the management of dams under multiple water use context. It clearly came out that the water resource management rules relegate flood-recession agriculture to the lowest priorities. In addition, there are safety issues related to unexpected effects of flooding on the water structures and in the nearby inhabited localities of flood-prone areas. Knowing some characteristics of the flooding and of the river’s levels and their relationships can be useful within the framework of an organized climate service that would help farmers and communities to better anticipate constraints.

Highlights

Natural or artificial constraints on river regimes have implications for various sectors, such as agriculture, habitat or ecosystem health [1,2]
Traditional production systems depending on the flooded surface areas are the most vulnerable to changes in hydro-climatic conditions and water allocation policies [6]
Volumes released at Manantali (Figure 5e) are lower than those at Diama, which means that other tributaries, the Faleme, contribute for a large part of inflows found downstream and to the flooding

Summary

Introduction

Natural or artificial constraints on river regimes have implications for various sectors, such as agriculture, habitat or ecosystem health [1,2]. These constraints are linked to hydrological hazards amplified by climate change, and by human action [3,4]. Regulating the flow of rivers considerably improves living conditions, but it can have a negative impact on downstream production systems and ecosystems and the populations that depend on them as well. In the Senegal River valley, the Manantali dam had adverse impacts on traditional production systems used by between 500–800,000 people [7]. Studies involving several disciplines report adverse effects in flood areas often used for flood-recession agriculture and for fishing [5,6,7,8]

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Discussion

Conclusion