Spatio-temporal variability of hydrological regimes around the boundaries between Sahelian and Sudanian areas of West Africa: A synthesis

Descroix, Luc; Mahé, Gil; Lebel, Thierry; Favreau, Guillaume; Galle, Sylvie; Gautier, Emmanuèle; Olivry, Jean-Claude; Albergel, Jean; Amogu, Okechukwu; Cappelaere, Bernard; Dessouassi, Robert; Diedhiou, Arona; Breton, Éric Le; Mamadou, Ibrahim; Sighomnou, D.

doi:10.1016/j.jhydrol.2008.12.012

Cited by 223 publications

(202 citation statements)

References 46 publications

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“…The Sahelian paradox is an observed runoff increase despite low rainfall. The same event was reported in other catchments such as Nakanbe (Burkina Faso) and Sirba (Niger) [25] and it represents an important challenge for modeling water availability in the basin. The paradox is also linked to recently reported flooding by local farmers, which can be attributed to the rapidly increasing population at the coastline of the rivers.…”

Section: Discussionsupporting

confidence: 64%

Farmers’ Responses to Changing Hydrological Trends in the Niger Basin Parts of Benin

2017

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Sub-Saharan Africa is highly vulnerable to climate change given its low capacities of resilience to the enormous challenges climate change will pose. Research aimed at evaluating changes in hydrological trends and methods of adaptation was conducted in the Niger Basin parts of Benin at the peak of the rainy season in the year 2012. Rainfall and river discharge were analyzed from 1950-2010 in order to generate patterns of changes in the region. Structured questionnaires were used to evaluate the perceptions of 14 farming communities on climate-related issues and their methods of adaptations. Mann-Kendall and Pettit trend analyses were conducted for rainfall and river discharge. The findings indicated that significant decreases characterized rainfall and river discharge in the period of study. Flash flood was considered the major challenge faced in the region according to more than 90% of crop, animal, and fish farmers. Aside from that, decrease in water availability was identified as an additional challenge. Irrigation, diversification, water treatment, drainage, small dams, and dikes were reported as the common adaptation mechanisms in the catchments. This study will help in designing sustainable adaptation mechanisms to abrupt changes in the hydrology of the region.

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Section: Discussionsupporting

confidence: 64%

Farmers’ Responses to Changing Hydrological Trends in the Niger Basin Parts of Benin

2017

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“…Extreme hydrological events such as droughts and floods are expected to increase in intensity under climate change scenarios, causing both environmental and socio-economic problems (Webersik and Wilson, 2009;IPCC, 2012). Desertification, desert encroachment and an alteration of hydrological regimes have already been observed in several African ecosystems and regions (IPCC, 2007;Descroix et al, 2009;Odjugo, 2010). A shortage of water can have a damaging impact on vegetation condition, agricultural production and livelihoods, as many African countries rely on low productivity rain-fed agriculture (Below et al, 2007;Assan et al, 2009).…”

Section: Introductionmentioning

confidence: 97%

A conceptual model for assessing rainfall and vegetation trends in sub‐Saharan Africa from satellite data

Hościło

Balzter

Bartholomé³

et al. 2014

Int. J. Climatol

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Policymakers, governments and aid agencies require operational environmental monitoring in support of evidence-based policy-making and resource deployment in crisis situations. For Africa, this is only feasible at sub-continental scale with a large network of automated meteorological stations, a large number of highly coordinated field observers or with satellite remote sensing. The challenge with satellite data lies in the derivation of meaningful environmental indicators. This article describes a conceptual framework for understanding satellite-derived indicators of rainfall and vegetation greenness trends over Africa. It attributes observed vegetation changes to climatic (i.e. rainfall linked) and non-climatic drivers. A decade of annual rainfall and vegetation data over sub-Saharan Africa was analysed using satellite-based rainfall estimates [Famine Early Warning System Rainfall Estimation 2.0 (FEWSNET RFE 2.0)] from National Oceanic and Atmospheric Administration's (NOAA's) Climate Prediction Centre and the Normalized Difference Vegetation Index (NDVI) obtained from the Satellite Pour l'Observation de la Terre Vegetation (SPOT-VGT) sensor. Rainfall and vegetation greenness trends were analysed for 759 administrative regions of sub-Saharan Africa to identify those regions that have experienced a negative, positive or stable rainfall/vegetation trend over the period [2001][2002][2003][2004][2005][2006][2007][2008][2009][2010]. The character of the relationship between the annual rainfall and max NDVI trends were examined to identify areas where the changes in greenness could be attributed to climatic (rainfall) and non-climatic (human land use or ecological disturbance) changes. Regions where increasing rainfall was associated with vegetation greening were found in West Africa, Central African Republic, West Cameroon and northeastern part of South Africa, whereas areas with evidence of 'climatic vegetation degradation' were located in Southern Madagascar, Nigeria, Kenya and the Garden Route region of South Africa.

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“…Panthou, 2014). For example we can cite the inundations that occurred from [2007][2008][2009] in Benin, Niger and Burkina-Faso (World bank, 2009) which caused drastic consequences in more field of development agriculture (destroyed cultivation), aquatic ecosystems, economy, urban drainage systems, energy distribution and social security by displacing people (Danida, 2008, Descroix et al, 2009. Likewise, the emblematic Niger River floods of 2010 and 2012 are the two most important floods ever recorded at the Niamey station since the beginning of the observation in 1929, causing heavy casualties to people living close to the river (Panthou, 2014).…”

Section: Introductionmentioning

confidence: 99%

Estimation of IDF Curves of Extreme Rainfall by Simple Scaling in Northern Oueme Valley, Benin Republic (West Africa)

Agbazo¹,

N’Gobi²,

Kounouhéwa³

et al. 2016

Earth sci. res. j.

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Rainfall intensity-duration-frequency (IDF) curves are of particular importance in water resources management, for example, in urban hydrology, for the design of hydraulic structures and the estimation of the flash flood risk in small catchments. IDF curves describe rainfall intensity as a function of duration and return period, and they are significant for water resources planning, as well as for the design of hydraulic constructions and structures. In this study, scaling properties of extreme rainfall are examined to establish the scaling behavior of statistical non-central moment over different durations. IDF curves and equations are set up for all stations by using the parameter obtained from scaling behavior, the location and scale parameters μ24 and σ24 of the Gumbel distribution (EVI) sample of annual maximum 1440 min rainfall data. In another hand, we have established the IDF curves for ten selected rain gauge stations in the Northern (Oueme Valley) parts of Benin Republic, West Africa by using the simple scaling approach. Analysis of rainfall intensities (5 min and 1440 min rainfall data) from the ten rainfall stations shows that rainfall in north-Benin displays scales invariance property from 5 min to 1440 min. For time scaling, the statistical properties of rainfall follow the hypothesis of simple scaling. Therefore, the simple scaling model applies to the rainfall in (Oueme Valley). Hence, the simple scaling model is thought to be a viable approach to estimate IDF curves of hourly and sub-hourly rainfall form rainfall projections. The obtained scaling exponents are less than 1 and range from 0.23 to 0.59. The empirical model shows that the scaling procedure is a good estimator as it is more efficient and gives more accurate estimates compared with the observed rainfall than the traditional method which only consists the Gumbel model in all stations for lower return periods (T<5 years) but not for higher return periods.Las curvas de precipitación Intensidad-Duración-Frecuencia (IDF) son de particular importancia en el manejo de los recursos hídricos, como es el caso de la hidrología urbana o para el diseño de estructuras hidráulicas y la estimación del riesgo de crecidas en pequeñas captaciones. Las curvas IDF describen la intensidad de las precipitaciones como una función con períodos de duración y recurrencia, lo que las hace significativas en la planeación de recursos hídricos así como en el diseño de construcciones y estructuras hidráulicas. Este estudio examina las propiedades de escala en precipitaciones extremas para establecer un comportamiento en momentos estadísticos marginales en diferentes períodos de duración. Se establecieron las curvas IDF y las ecuaciones para todas las estaciones a partir del parámetro obtenido del comportamiento de escala, la ubicación y los parámetros de escala μ24 and σ24 de la muestra de información de precipitación máxima anual de 1440 minutos de la distribución de Gumbel (EVI). Por otro lado, se establecieron las curvas IDF para 10 estaciones pluviométricas sele...

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Spatio-temporal variability of hydrological regimes around the boundaries between Sahelian and Sudanian areas of West Africa: A synthesis

Cited by 223 publications

References 46 publications

Farmers’ Responses to Changing Hydrological Trends in the Niger Basin Parts of Benin

Farmers’ Responses to Changing Hydrological Trends in the Niger Basin Parts of Benin

A conceptual model for assessing rainfall and vegetation trends in sub‐Saharan Africa from satellite data

Estimation of IDF Curves of Extreme Rainfall by Simple Scaling in Northern Oueme Valley, Benin Republic (West Africa)

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