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Zinder, Niger

Mamadou I.,University of Zinder | Gautier E.,French National Center for Scientific Research | Descroix L.,IRD Montpellier | Noma I.,University Abdou Moumouni | And 6 more authors.
Catena | Year: 2015

For two decades, the Niamey area, in Niger, has undergone the creation of several new wadis ("koris" in hausa, the most spoken language in West Africa). The significant runoff increase in the Sahelian reach of Niger river makes us interested in the behavior of the basins of the tributary koris of Niger River in the Niamey area, in Niger. These koris generally formed during a single storm event, within depressions previously occupied by ponds; these ponds are overflown creating a new "kori". This study examines in detail the causes of this new exorheism mechanism. The main explanation of this evolution has been determined as being the strong runoff increase, related to an extension of crusted soils due to agricultural practices, mostly the reduction of fallow duration. The degradation of their structural stability leads to crusting and a strong reduction of their hydraulic conductivity. This is linked to water and sediment balance at the catchment scale. © 2015 Elsevier B.V.


Mounir Z.M.,Wuhan University | Mounir Z.M.,University of Zinder | Moustapha A.M.,University Abdou Moumouni | Gao C.S.,Wuhan University | Yi S.,Wuhan University
Journal of Environmental Hydrology | Year: 2013

Niger is one the most arid countries in Africa; Niger currently faces an imbalance between water demand and availability, primarily due to natural water scarcity as well as uneven water distribution. Rapid population and irrigation growth, among other economic and social factors, are likely to worsen the situation. The lower valley of the Tarka (Basse Vallée de la Tarka or BVT), the subject of this study, is an area suitable for irrigated farming with accessibility to groundwater and quality soils. Using WEAP (the Water Evaluation And Planning) model to establish different scenarios, we demonstrated that the BVT has good potential to improve the local population well-being.


Abdou M.M.,University of Zinder | Abdou M.M.,Joseph Fourier University | Vandervaere J.-P.,Joseph Fourier University | Descroix L.,IRD Montpellier | And 5 more authors.
Biotechnology, Agronomy and Society and Environment | Year: 2015

Description of the subject. The present study aims to present and analyze the evolution of the hydraulic conductivity of soils in cultivated and fallow areas in the loamy-sand superficial soils within the granitic basement region of West Niger. To this end, experimental plots considered representative of the area were chosen in the Sahelian cultivated area. Objectives. Our objective was to evidence the effect of cultural practices and of both wet hoeing and dry hoeing on this evolution and their consequences in terms of soil infiltrability and runoff. Method. A tension disc infiltrometer was used together with a pair of minitensiometers in one-dimensional flow geometry. Results. Measurements were carried out and variations in total rainfall were calculated, allowing us to determine and quantify the effects of the following on the evolution of conductivity: (i) hoeing, (ii) the level of soil moisture prior to this operation and (iii) the lack of cultivation in fallow areas. Hydraulic conductivity was consistently found to be minimal at the surface. Conductivity in the fallow field was stable at 20 mm.h-1. In the cultivated zones, conductivity was very high (120 mm.h-1) after hoeing in wet conditions, decreasing to the fallow value after 70 mm of rain and even down to half of this value after 230 mm of rain. Hoeing in dry conditions showed poor efficiency, both in terms of conductivity and the duration of the effect. Conclusions. The benefits of hoeing were found to be only short-lived, with the task needing to be repeated after 100 mm of rain. © 2015, FAC UNIV SCIENCES AGRONOMIQUES GEMBLOUX. All rights reserved.


Amogu O.,Joseph Fourier University | Amogu O.,Tractebel Engineering | Esteves M.,Joseph Fourier University | Vandervaere J.-P.,Joseph Fourier University | And 19 more authors.
Hydrological Sciences Journal | Year: 2014

Land-use changes have been significant these last decades in West Africa, particularly in the Sahel region; in this area, climatic and demographic factors have led to a rise in cropped areas in recent decades causing strong changes in the water cycle and in river regimes. This study compares the rainfall–runoff relationships for two periods (1991–1994 and 2004–2011) in two small and similar neighbouring Sahelian catchments (approx 0.1 km2 each). This allows identification of the different hydrological consequences of land-use/land-cover change, particularly the fallow shortening and the consequent degradation of topsoil. The main land surface change is a 75% increase in crusted soil area. Runoff increased by more than 20% on average between the two periods while flood duration decreased by 50% on average. However, runoff values remained largely constant in the lower part of the northern basin due to a strong increase in in-channel infiltration. © 2014, © 2014 IAHS.


Torou B.M.,International Water Management Institute | Favreau G.,IRD Montpellier | Barbier B.,CIRAD | Pavelic P.,International Water Management Institute | And 2 more authors.
Water International | Year: 2013

Land-use-change-induced increases in shallow groundwater levels across parts of the Sahel in recent years have coincided with expanded use of groundwater for irrigation. This study was conducted to assess the potential linkages and livelihood implications based on a field survey of nine villages building on previous hydrological studies. The results show that irrigators lack effective means of production and mostly rely on manual methods. Borehole usage is more profitable and reliable than shallower wells. Overall incomes from irrigation are relatively small and severely constrained by the limited field scale due to high establishment and operating costs. © 2013 2013 International Water Resources Association.

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