Paturel J.-E.,1RD HSM |
IAHS-AISH Proceedings and Reports | Year: 2014
Since 1970 Africa has experienced a significant change in climate. It has resulted in a sharp decrease in rainfall but also an increase in temperature. The study looked at 36 climate indices derived from daily meteorological data of rainfall and temperature in the basin of the Bani in Mali (130 000 km2). The detailed description of the evolution of the climate in this area since 1950 has been conducted in terms of statistical analysis of mean variables but also extreme variables. Results show significant changes in temperature extremes associated with warming, especially for those indices derived from daily minimum temperature. The entire study area shows a significant decrease in the annual occurrence of cold nights and a significant increase in the annual occurrence of warm nights. Indices derived from daily maximum temperature show less significant differences. Changes in precipitation derived indices show a downward trend. Globally, the changes occurred first on the indices related to rain (around 1970), and then on the indices related to temperature (around 1980). © Copyright 2014 IAHS Press.
Polcher J.,French National Center for Scientific Research |
Parker D.J.,University of Leeds |
Gaye A.,LPAO SF UCAD |
Diedhiou A.,LTHE IRD |
And 12 more authors.
Atmospheric Science Letters | Year: 2011
The AMMA (African Monsoon Multidisciplinary Analysis) project set out to better understand the geophysical processes which govern the evolution of the monsoon and provide the science needed to improve prediction and decision-support systems. The control exerted by weather and climate on agronomic production, water resources and public health was studied to evaluate the potential for populations to adapt. AMMA made advances which have the potential to improve forecasts from weather to climate scales. Translating them into operational tools for decision making will require improvements to the observational networks, and stronger support for the organizations which generate and disseminate application forecasts. Copyright © 2011 Royal Meteorological Society.
De Fraiture C.,UNESCO IHE |
Kouali G.N.,International Water Management Institute IWMI |
Sally H.,International Water Management Institute IWMI |
Agricultural Water Management | Year: 2014
Small reservoirs in Burkina Faso are constructed for many purposes such as domestic water uses, livestock watering and irrigated rice production downstream of the dam. Increasingly farmers use individually owned motorized pumps to draw water directly from the reservoir and irrigate vegetables upstream of the dam. This practice, while tolerated, is unauthorized and referred to as 'irrigation pirate' in French. Upstream vegetable cultivation is successful because it is more profitable than downstream rice cultivation. Often, the 'unofficial' irrigated area around the reservoir is much larger than the official command area below the dam. However, in the absence of an overarching authority to manage the water source, this may lead to conflicts and resource degradation. We take the example of the Korsimoro reservoir in Burkina Faso to illustrate the positive and negative impacts of spontaneous individual irrigation around communally managed water bodies. © 2013 Elsevier B.V.
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.
Descroix L.,Joseph Fourier University |
Laurent J.-P.,Joseph Fourier University |
Vauclin M.,Joseph Fourier University |
Amogu O.,Joseph Fourier University |
And 14 more authors.
Journal of Hydrology | Year: 2012
Despite the strong reduction in rainfall observed after 1968, the water table of some endorheic areas in the Sahel has been found to be rising over the last several decades. It has been previously demonstrated that this is due to land use changes which have led to a severe increase in runoff and erosion. In such areas, the excess in runoff causes a strong increase in the number of ponds, their sizes and thus, their duration. Ponds have been identified as the main zones of deep infiltration of water. The aim of this study was to investigate whether other areas of the Sahelian region could also be defined as deep infiltration ones as well, and then, whether they were contributing to aquifer recharge. Soil water content was surveyed for five consecutive years (2004-2008) by implementing a set of measurement devices at different depths. The hydrologic water balance was monitored at stream flow gauge stations located upstream and downstream of two small endorheic catchments. The observed replacement of bush vegetation by crops and fallow areas led to the appearance of extended bare soil areas due to both aeolian and hydric erosion, triggering a strong reduction in soil infiltrability under millet fields and fallow lands as well as in the soil water holding capacity. It also resulted in the formation of a great number of gullies and sand sediment deposits in the endorheic areas. Measurements showed that sandy deposits correspond in fact to large areas of deep infiltration: tens of thousands of cubic meters of water infiltrated catchments of less than 1km 2. Runoff decreased by up to 50% in the sandy deposit areas, while infiltration (close to 1300mmh -1) was observed up to depths of 10m. These factors would raise the water table and significantly modify the surface and sub-surface components of the water cycle. © 2011 Elsevier B.V.
Poussin J.-C.,IRD Montpellier |
Renaudin L.,CIRAD - Agricultural Research for Development |
Adogoba D.,CSIR SARI |
Sanon A.,INERA |
And 6 more authors.
Water Resources and Rural Development | Year: 2015
A major direct use of water from West African small reservoirs is irrigation. Analyzing the performances of irrigated agriculture is therefore a useful way to measure the impact of small reservoirs on food security and livelihoods of local communities. The aim of this study was to assess the performance of two such irrigated schemes in the Upper Volta basin (one in Burkina Faso and the other in Ghana) through participatory methods, to jointly identify major constraints, and to discuss possible solutions with local communities. The agronomic and economic performance of irrigated agriculture at both sites were far from satisfactory, due to the lack of maintenance of the small reservoirs and irrigation schemes, sub-optimal crop management, and poor product marketing. These issues were analyzed with the farmers across differing sub-schemes and cropping systems and some solutions were envisaged. Our assessment showed that farmers often had difficulty obtaining quality agricultural inputs and marketing their products. The poor performance of irrigated crops, due to poor condition of hydraulic infrastructures, poor agronomic management, and organizational failure provided only limited incomes for local households. Nevertheless, the existence and the many uses of small reservoirs improved food security and created indirect activities that also enhanced livelihoods. The local authorities generally considered preserving water to be a priority in small reservoir management, but the degradation of irrigation schemes could happen quickly and result in scheme failures, thus reducing indirect economic activities and causing under utilization or even abandonment of the small reservoir, unless appropriate measures are taken. © 2015 Elsevier B.V.
Analyses of pluviometric grids and main features of the changes occurring in west and central africa during the 20th century [Analyses de grilles pluviométriques et principaux traits des changements survenus au 20ème siècle en Afrique de lOuest et Centrale]
Paturel J.E.,IRD Montpellier |
Boubacar I.,2iE |
L'Aour A.,IRD Montpellier |
Mahe G.,IRD Montpellier
Hydrological Sciences Journal | Year: 2010
Using monthly grids of rainfall data provided by the Climate Research Unit (CRU) of the University of East Anglia, UK, we have undertaken analysis of the main features of the changes in rainfall regime that they highlight in West and Central Africa during the 20th century. From these data grids, and using robust statistical analysis tools, it is shown that during the last century West and Central Africa experienced alternations of dry and rainy seasons with very variable spatial and temporal extent. North of the Equator, the clearest climatic changes were droughts, while south of the Equator; a series of much wetter periods occurred. During the first half of the century, the changes tended to correspond to an increase in the annual rainfall, whilst the inverse tendency was seen afterwards, with a peak at the end of the 1960s and the beginning of the 1970s. The latter period is marked by an agricultural, hydrological and climatic drought that is the greatest in significance and intensity both statistically and in human memory. Numerous studies carried out at smaller scales confirm this overall analysis, even if, sometimes, they may highlight some local or regional characteristics that the data used by the CRU and the spatial resolution of the grids cannot always reveal. Nevertheless, these grids can be of good utility in regional hydrology. © 2010 IAHS Press.
Danuor S.,Kwame Nkrumah University Of Science And Technology |
Gaye A.,Cheikh Anta Diop University |
Yacouba H.,2iE |
Mariko A.,University Of Bamako |
And 9 more authors.
Atmospheric Science Letters | Year: 2011
Countries in Africa are the most vulnerable to the impacts of climate change but lack the capacity to manage effectively climate-related environmental problems. Meteorology and climate education programmes are offered at West African universities, but the poor job market and insufficient funds from governments are impacting negatively on the running and sustainability of master's and PhD programmes. This situation compels students to pursue further studies and seek their fortune abroad, a practice which leads to brain drain. One of the AMMA initiatives is to develop international postgraduate programmes and to seek funding to provide students and lecturers with grants and fellowships. Copyright © 2011 Royal Meteorological Society.
Paturee J.-E.,RD HSM UM II |
Boubacar I.,2iE |
Laour-Cres A.,RD HSM UM II |
Mahe G.,RD HSM UM II
Revue des Sciences de l'Eau | Year: 2010
ORSTOM, today IRD ("Institut de Recherche pour le Dé veloppement"), is a French institute of research that has been conducting research in Africa for the last 60 years. Since this period, agroclimatologists and hydrologists of IRD have never stopped collecting, validating and completing hydroclimatic data over West and Central Africa. In the view of modelling runoff in this part of the world, our team, HydroSciences Montpellier (HSM), manages an hydroclimatic and environmental database (SIEREM). Using all the collected pluviometric data, we have been calculating monthly rainfall on a regular 0.5° * 0.5° gridding, each mesh corresponding to approximately 2,750 km2. To assess the value of these gridded rainfall data, we compared them with those provided by the Climate Research Unit of University of East Anglia (CRU-UEA). The IRD and CRU grids are very similar but the former IRD grids are computed from more stations and have proven to be more reliable when predicting stream flows using two rainfall-runoff models. These grids are available from free of charge from SIEREM database website (http://www.hydrosciences.fr/sierem/index.htm).
Barbier M.T.,CIRAD - Agricultural Research for Development |
Giroux F.,Montpellier Sup Agro |
Coulibaly Y.,2iE |
Marouze C.,CIRAD - Agricultural Research for Development
ARPN Journal of Engineering and Applied Sciences | Year: 2014
A knowledge-based tool was implemented in order to assist in the design of food processing equipment. It was developed and suggested for the use of professionals who are seeking creative solutions for processing principles in a given context and under specific constraints, especially in the context of weak knowledge of food engineering and material properties, poor economic conditions, and impossibility of efficient use of existing design methodologies. This is usually the case in many developing countries where equipment supply is mostly limited to copies and adaptations of a few models despite the big size of small scale food processing sector, which results in the use of unsuitable equipment, lack of efficiency, and bad quality. This new tool uses knowledge-based methodology starting with the identification of the most useful function (MUF) to be achieved in order to identify the main product property change, hence leading to the implementation of the targeted product. MUFs are linked to scientific effects that can achieve them in order to suggest designers a wide range of potential solutions. To facilitate and orient access to useful knowledge for a given problem of food processing principles, this tool is designed using a database program and links to related and existing web-based sites. Selection of optimal equipment types is finally carried out by combining users' manufacturing skills and specifications in terms of cost, maintenance and current use scheme. © 2006-2014 Asian Research Publishing Network (ARPN).