Niger Basin Research Articles

Projected impact of solar radiation modification geoengineering on water deficit risk over major Central African river basins

Abstract The economy of Central African countries strongly depends on rain-fed agriculture and hydropower generation. However, most countries in this subregion do not yet have the irrigation technologies that are already applied in many more advanced nations, which further exposes them to the serious risk of severe drought caused by global warming. This study investigates the potential impact of solar radiation modification (SRM) geoengineering on the water availability over the four major river basins that cross most of Central African countries (i.e. Niger Basin, Lake Chad Basin, Cameroon Atlantic Basin (CAB) and Congo Basin). For this purpose a potential water availability index was computed based on an ensemble-mean simulations carried out in the framework of Phase 6 of the Geoengineering Model Intercomparison Project considering two SRM simulation experiments: the stratospheric sulphate aerosol injection (G6sulfur) and the global solar dimming (G6solar). The climate change simulation results in a robust decreases by up to 60% in water availability, most pronounced over the CAB under the high radiative forcing scenario. Therefore, in a business-as-usual world, the reduction in water availability combined with the rapid population growth expected by 2050 in the studied subregion, could result in a significant water deficit over Central African countries towards the end of the 21st century. This water deficit could affect all activities that depend on water resources, such as water supply, agriculture and hydropower generation. Furthermore, the results also show that SRM methods have the potential to significantly reduce this deficit by increasing water availability (as compared to climate change) by up to 50% over the affected river basins, with a more accentuated increase found in the CAB when the global solar dimming is applied. These results suggest good possibilities of adaptation for populations living in the geographical areas of these river basins.

Comparative Analysis of Spatial Impact of 2012 and 2022 Flood Disaster along Lower Niger Basin in Nigeria

Comparative Analysis of Spatial Impact of 2012 and 2022 Flood Disaster along Lower Niger Basin in Nigeria

Integrated assessment of flood susceptibility and exposure rate in the lower Niger Basin, Onitsha, Southeastern Nigeria

BackgroundVarious methods have been utilized to investigate and mitigate flood occurrences, yet there is a paucity of literature on factors, such as soil compositions, that contribute to persistent flooding in river basins like the Lower Niger catchment, specifically at Onitsha. Furthermore, the study seeks to furnish essential geospatial data concerning flood vulnerability, flood risks, and exposure rates in the Lower Niger Catchment area, situated in Onitsha, southeastern Nigeria.Materials and methodsSoil samples were collected from 10 specific locations identified through GPS and ground-truthing techniques. Additionally, satellite imagery from the Landsat Enhanced Thematic Mapper (ETM +) was utilized, with supervised classification employed to extract feature classes. Analysis operations were conducted using IDRISI software, resulting in the creation of digital elevation models (DEMs), susceptibility maps, and flood-risk zones.ResultsAnalysis revealed that the predominant soil composition in the study area comprises sandy (84.8%), silt (8.1%), and clayey (7.1%) soils. Utilizing these soil characteristics alongside relevant aerial data, exposure rates were determined at various scales to delineate the most flood-vulnerable zones in the basin. It was found that certain areas, accommodating a population exceeding 79,426 across 2,926.2 ha, were particularly susceptible to flooding. Notably, major markets such as Bridgehead, Textile, and Biafra were identified as highly susceptible, with varying degrees of risk. The prevalence of sandy soil, which facilitates increased rainwater infiltration but is also prone to rapid saturation and runoff, likely contributes to the heightened susceptibility to flooding in these areas.ConclusionGeospatial analysis employing remote sensing data indicates the high susceptibility and exposure to flooding in the lower Niger River Basin around Onitsha. Urgent mitigation efforts are imperative, necessitating the establishment of zoned areas equipped with effective drainage systems to safeguard vulnerable populations.

Potential Impact Assessment of Climate Change on Food Security in Niger Basin Countries using Panel ARDL Analysis

Potential Impact Assessment of Climate Change on Food Security in Niger Basin Countries using Panel ARDL Analysis

The Middle Niger Basin in Nigeria Has a Rift Origin, as Revealed by the Inversion and Modeling of Gravity and Magnetic Data

AbstractThe NW‐SE oriented Middle Niger Basin, which is a Campano‐Maastrichtian inland basin has been the subject of debate among geoscientists regarding its origin and development. This paper aims to unravel the basin's origin and evolution by using high‐resolution magnetic, gravity, and topographical data. The integration of aeromagnetic and gravity data provides a means to assess the influence of igneous intrusions during the basin's evolution. The study presents a new perspective on the origin of the basin, suggesting a rift origin where orthogonal extension played a crucial role in its evolution. The research also investigates the relationship between intrusive rocks and the formation of the basin, finding these rocks are solely located within the basement. The magnetic and gravity maps reveal anomalies associated with intrusive structures within the Precambrian crystalline basement. This is a common feature shared with rifted basins on a global scale.

Land use planning and climate change adaptation in river-dependent communities in Nigeria

Land use planning and climate change adaptation are critical for ensuring sustainable development and resilience in river-dependent communities in Nigeria. This study examines land use planning and climate adaptation in river-dependent communities in the Lower Niger River region of Nigeria. The research utilizes a mixed-methods approach. Data for the study were gathered from 198 households through surveys, complemented by 17 qualitative interviews and remote sensing techniques to assess land use changes and community perceptions. Findings reveal a notable trend where poor farmers face heightened vulnerability to climate change due to financial constraints, hindering their adoption of adaptive land use strategies. Specifically, more than half of the sampled households possess individual land for agricultural purposes yet lack the resources to effectively mitigate climate-related risks. Among the studied communities, Odekpe emerged as particularly vulnerable, with a prevalence of vulnerability at 32.3% and higher exposure to flood-prone zones.The quantitative analysis delineates community engagement in land management practices, showcasing proactive resource allocation and conflict resolution efforts among over 60% of participants. However, a significant portion (57.6%) lacked awareness of hydrological changes, potentially impeding effective land use planning and adaptation measures.Further analysis through remote sensing and mapping techniques revealed shifts in land use land cover, highlighting a transition from predominantly vegetated areas to built-up regions over the past three decades. The flood vulnerability assessment maps underscored substantial vulnerability across the Lower Niger basin, especially in downstream regions, indicating heightened risks due to proximity to the Niger River and heavy rainfall.Qualitative insights from stakeholder interviews identified challenges impeding effective land use planning, including uncertain climate projections, insufficient data, institutional capacity constraints, and conflicting priorities. Additionally, participants emphasized the need for resilient land use decisions to address urbanization impacts, altered drainage patterns, and diminishing green spaces. The study recommends several key actions to enhance the effectiveness of land use planning and climate adaptation in the Lower Niger River region. These include the imperative to strengthen institutional capacities, improve stakeholder engagement processes, integrate traditional knowledge and practices into planning efforts, fortify legal frameworks governing land use, and prioritize the promotion of sustainable livelihoods among local communities.

STREAMFLOW GENERATION OF RIVER NIGER BASIN KOGI USING MODIFIED THOMAS FIERRING MODEL

There is a concerted effort towards protection of environment as a result of incessant change of climate and its resultant effects on human live and property. Studies have shown that flooding is ranked the most devastating natural disaster in the world; and it is a common natural environmental hazard in various parts of Nigeria. In recent times, flooding has been reported to constitute a major challenge to about 1.5 billion people or 19% of the world population; whereas 70 million people globally exposed to flooding every year while over 800 million people are living in flood-prone areas. The 2022 destructive flooding in River Niger Basin Lokoja Nigeria has attracted attention of experts with a view to curtailing the future reoccurrence. Based on this rationale, this study aimed to determine the trend in the hydrometric dataset and to provide extensive time series analysis of the streamflow in the study area using Modified Thomas Fierring Model (MTFM). In order to achieve the objectives of the study, the dataset for 20 years was sourced from the NIWA (National Inland Waterway Authority) whereby the daily and monthly data was extensively analyzed and the (Thomas Fierring) T-F model the data for the “n” years was divided into 12 sections while the data of each month was re-aggressed to the previous month so that there were 12 linear regressions. Also, MTFM was used to predict the monthly flows from River Niger from 2000 to 2019 so as to compute 36 parameters (12) means (), standard deviations (), and Lag-1 autocorrelation coefficients (r1)). After the estimation of the parameters of the MTFM, the series of historical monthly flows for 20 years were generated. These series were compared with the recorded monthly flows of River Niger for the hydrological period of 20 years (2000-2019), with the use of basic statistical characteristics like mean, standard deviation, maximum, minimum, coefficient of variation, skewness and Kurtosis as shown in Table 1 and Figure 2. The findings revealed that monthly discharge time series of River Niger Basin from 2000 to 2019 are consistent with slightly variation in the trends after modified modified Thomas Fierring Model application; and the study further underscored the relevance of MTFM for analyzing streamflow of River Niger Basin Lokoja. Among others, the study recommended up-to-date hydrometric data of River Niger Basin for optimum control and management of streamflow in the study area; and concluded that up-to-date information in this direction will help future researcher to consolidate on the existing body of knowledge in the field.

Predicting River Discharge in the Niger River Basin: A Deep Learning Approach

Across West Africa, the River Niger is a major source of freshwater. In addition, the river system also provides services such as aquaculture, transportation, and hydropower. The river network plays a critical role in the hydropolitics and hydroeconomics of the region. Therefore, River Niger is integral to the development of West Africa, hence, there is a need to ensure that the river’s ecosystem is a healthy one. In light of the changing climate and its associated threats such as droughts and floods, constant monitoring and measurements of the the river’s flow system cannot be overemphasized. This study investigates temporal variations in annual river discharge characteristics at eight stations (Koulikoro, Dioila, Kirango, Douna, Mopti, Dire, Ansongo, and Niamey) in the Niger River basin, presenting detailed quantitative findings. Analyzing discharge data of River Niger from 1950 to 1990, the minimum discharge measures (minimum and 10th percentile) exhibit a consistent decreasing trend post-1960, persisting into the 1990s at several stations. Central tendency measures (mean and 50th percentile) also consistently reduced since 1950, with near-zero median values observed in Diola and Douna. Recovery in mean discharge is evident in Ansongo after 1980. Extreme values (maximum and 90th percentile) show decreasing trends across all stations, with some locations exhibiting a slight recovery after 1980. The decreasing trend in annual minimum, mean, and maximum values has implications for water resources, affecting hydroelectric generation, fish farming, and dry season irrigation. Machine learning algorithms (MLAs) are deployed to predict the prediction of monthly river discharge, with LSTM identified as the best-performing model overall. However, model performance varies across locations, with TCN excelling in Diola but underperforming in Koulikoro. This study emphasizes the chaotic nature of time series data and external drivers limiting the long-term predictive capabilities of MLAs. Quantitative evaluation of MLA performance reveals specific strengths and weaknesses at each station. This study underscores the importance of predicting the 10th percentile of annual river discharge for water resource planning. Models exhibit diverse performance across basins, emphasizing the need for tailored approaches. Further analysis considers measures of central tendencies, predicting the 50th percentile (Q50) and mean discharge values. TCN emerges as the best model for Q50 prediction, showcasing superior performance over other models. Additionally, the study delves into predicting high and low extreme discharges, crucial for understanding potential flood events and preparing for meteorological and hydrological droughts. This study concludes by emphasizing the necessity for location-specific studies in the River Niger basin to facilitate an enhanced integrated river management system.

Remote sensing analysis of desert sensitive areas using MEDALUS model and GIS in the Niger River Basin

Environmental degradation is a dynamic issue that requires ongoing monitoring to ensure ecological repair and environmental management for sustainable development. This study employed remote sensing techniques to ascertain the desertification sensitivity areas in the Niger River Basin (NRB) using the MEDALUS Model. The indicators for the model were divided into three categories: vegetation quality,climate quality, and soil quality index. The net primary productivity, estimated by the Carnegie Ames Stanford Approach model was substituted in the vegetation quality index. Each quality index was computed by calculating the geometric mean of selected sub-indices, while the geometric mean of the three quality indicators was utilized to determine the Environmental sensitivity to desertification in the study area. A total of 26.10% of the study area had low soil quality, while 26.16% and 17.41% of the study area had low vegetation and climate indicators, respectively. The study revealed that about 36.56% of the study area is highly sensitive while 27.65% and 35.78% are moderately and less sensitive respectively, to desertification in the NRB. The desertification-sensitivity index map shows that the northern part of the study area is highly susceptible to desertification and is encroaching southwards. The findings reveal that climate variables are major influencers in the study area. Our research is of importance to the Niger Basin Authority, planners, and other government agencies in charge of protecting the environment, to ascertain the sensitive areas to desertification, and to help cushion the effect of land degradation in the NRB.

Carbon (CO2) emission and food availability convergence in the Niger Basin region: Insight from a club clustering algorithm

The study employed the Phillips and Sul log-t convergence test to analyse the degree of convergence for the Niger Basin region (NBR) countries in terms of per capita carbon emission and food availability. We found that, between the years 1986 and 2020, the Niger Basin region produced 13.5% less food per person than it did during the base period of 2004 to 2006. This study also found a strong convergence among the NBR countries on per capita food production. The result for the region’s convergence of per capita carbon emission was rejected. The non-convergence of the entire sample, and the presence of the different subgroup convergence clubs for per capita CO2 emission for the region, implies that individual factors characterise the NBR countries in terms of per capita CO2 emissions, which in turn determine an idiosyncratic course of their transition path for per capita CO2 emission policies. Considering that the transboundary river basin links nine countries, this study recommends that the NBR countries formulate and implement CO2 emission policies based on cluband country-specific policies to achieve convergence in relation to a concerted food security threat facing the region.

Landuse, landcover change dynamics and flooding in the lower Niger basin Onitsha, South Eastern Nigeria

This study looked at the factors contributing to Onitsha's incessant flooding, specifically landuse and land cover depletion. The landuse/landcover changes during a period of ten years (2008 – 2018) and the relevant variables were studied in the lower Niger Basin, focusing on Onitsha, Anambra State. Three sets of Enhanced Thematic Mapper Plus (ETM+) Landsat imagery maps from 2008, 2013, and 2018 were used to construct three Geographic Information Systems (GIS) based landuse/landcover maps of the research location and cross-tabulation method was adopted for the Change Detection analysis. The results demonstrated that between 2008 and 2013, built-up areas expanded by 9.4%, and between 2013 and 2018, they increased by 9.4%. Then it grew by 5.5%, resulting in a total area of 470 ha and 275 ha. Then, between 2008 and 2018, built-up added 745 ha in the study region, whereas vegetation lost 638 ha between 2008 and 2013, and another 97 ha between 2013 and 2018, for a total loss of 735 ha. Between 2008 and 2013, the area of bare ground increased by 1.3%, to 65 ha, while between 2013 and 2018, the area of bare ground decreased by 0.3%, to 15 ha. This study also discovered a 40-hectare rise in waterbody between 2008 and 2013 and a 100-hectare loss between 2013 and 2018. Based on the findings, the changes in landuse/landcover change detection provided insight into non-compliance with existing landuse acts and the implementation strategies of government agencies enforcing them.

Identification of Drought Events in Major Basins of Africa from GRACE Total Water Storage and Modeled Products

Terrestrial water storage (TWS) plays a vital role in climatological and hydrological processes. Most of the developed drought indices from the Gravity Recovery and Climate Experiment (GRACE) over Africa neglected the influencing roles of individual water storage components in calculating the drought index and thus may either underestimate or overestimate drought characteristics. In this paper, we proposed a Weighted Water Storage Deficit Index for drought assessment over the major river basins in Africa (i. e., Nile, Congo, Niger, Zambezi, and Orange) with accounting for the contribution of each TWS component on the drought signal. We coupled the GRACE data and WaterGAP Global Hydrology Model through utilizing the component contribution ratio as the weight. The results showed that water storage components demonstrated distinctly different contributions to TWS variability and thus drought signal response in onset and duration. The most severe droughts over the Nile, Congo, Niger, Zambezi, and Orange occurred in 2006, 2012, 2006, 2006, and 2003, respectively. The most prolonged drought of 84 months was observed over the Niger basin. This study suggests that considering the weight of individual components in the drought index provides more reasonable and realistic drought estimates over large basins in Africa from GRACE.

The role of teleconnections and solar activity on the discharge of tropical river systems within the Niger basin

The behavior of tropical river systems is driven by some internal and external factors. Understanding the role of these external forces, such as large-scale oscillations, on river discharge will provide insight into their dynamic complexities and modelling. In this study, the role of teleconnection patterns and solar activity on river discharges within the Niger basin was considered using both linear (correlation) and nonlinear (multifractal and joint recurrence analysis) statistical approaches. Correlation analysis suggests the existence of a linear relationship between tropical teleconnection patterns in the Atlantic and Pacific oceans with river discharge in the Niger basin. Nonlinear relationships were investigated using multifractal formalism and joint recurrence quantification analysis. A strong nonlinear relationship was observed between the teleconnection patterns and river discharge in Diola while other stations (Koulikoro, Ansongo, Niamey, Mopti, Kirango) showed no such relationship. The observation at Diola is attributed to its location (coastal) among other things. The multifractal strengths were found in the range of 0.58-2.86, suggesting fractal correlations between the parameters. There was no conclusive evidence of a linear and nonlinear relationship between solar activity and tropical river discharge within the Niger basin.

Pyrite Dissolution in the Cretaceous Yogou Formation of the Niger (Chad) Basin: Implications for Basin Evolution under a Rift Tectonic Setting.

This is the first study of pyrite minerals in the entire West and Central African Rift System (WCARS). Several polished organic-rich core samples from the Cretaceous Yogou Formation of the Niger (Chad) Basin located in the WCARS were investigated for their pyrite content using FE-SEM and SEM-EDS imaging techniques. An attempt was made to classify the types and provenance of the pyrites and to highlight the control of rift fractures on the oxidation and dissolution of pyrites in the region. Three major types of pyrites are present in the studied formation, including euhedral pyrite (EPy) crystals, pyrite framboids (FPy), and sunflower pyrites (SPy). A statistical analysis of 307 FPy shows that the framboids are diagenetically formed with an average diameter of 6.61 μm. SPy is present in a relatively low amount compared to framboids. The pyrites underwent a variety of diagenetic modifications, from mechanical compaction to oxidation, dissolution, and recrystallization. Unoxidized pyrites primarily contain Fe, S, and C, but oxidized pyrites also contain O, Al, and Si. There is a strong correlation between the fractures and the spatial distribution of the physicochemical alteration of the pyrite in the study. Dissolution in relatively deep-buried samples occurs mainly along fracture planes. The fractures provide a pathway for oxidants and other metal elements to reach the pyrites. The pattern of pyrite dissolution reflects the timing of fracture formation and fracture activities as a purveyor or drainage for fluids in the organic-rich samples investigated. The pyrites are associated intimately with organic matter (OM); thus, the relationship between the fracture and the pyrites' transformation is significant in the assessment of organic matter preservation at deep-burial depth.

Quantitative similarities between the banjo and a diverse collection of West African lutes

The banjo entered world musical culture through the ingenuity of communities of enslaved Africans in the Caribbean. The banjo is rooted within the lute-playing traditions of West Africa, where several remarkably banjo-like instruments and playing styles exist today. The banjo is a creation of the Black diaspora, however, and has no obvious single ancestor among extant West African lutes. Understanding the relative similarities between extant West African lutes and the gourd banjo may shed light on the cultural context of banjo origins. This study examines structural similarities between the gourd banjo and 61 West African lutes using two quantitative approaches for measuring and representing similarity among entities (UGPMA and NeighborNet). The banjo groups with a cluster of lutes from peoples in the Senegambia region speaking Bakic languages, which includes the Jola ekonting, an instrument that has garnered considerable recent attention as a banjo relative, but also shows similarities to lutes from the Niger Basin. This suggests that the relatively egalitarian social context of lute playing seen in Bakic language-speaking cultures may have been especially influential on the development of the banjo among enslaved populations in the Caribbean, but that the banjo draws on heterogeneous cultural influences and that more attention should be paid to the influence of eastern Sahel musical cultures on the evolution of the instrument.

Changes in aquifer properties along a seasonal river channel of the Niger Basin: Identifying groundwater recharge pathways in a dryland environment

In drylands of tropical Africa, groundwater plays a fundamental role in alleviating food insecurity and adapting to the effects of climate change. Substantial uncertainty persists in the renewability of groundwater resources in drylands and recharge pathways through the surface geology. Here we characterize the architecture and hydrogeological properties of alluvium and underlying sandstone and crystalline basement rocks along the ephemeral River Goulbi de Maradi in the Iullemmeden Basin of Niger using Magnetic Resonance Soundings (MRS), Time-Domain Electromagnetic (TDEM) soundings, and borehole lithological data. Considerable variations in lithological facies and hydrophysical properties are found along a series of 5 transects perpendicular to the seasonal/ephemeral river channel and adjacent plateaux of the Continental Hamadien (CH) sandstone. The CH aquifer comprises a pebbly sand facies upstream and sandstone clay facies downstream with Farak-type sandstones located at the base of the two facies. Consistent with these variations in facies, the geophysical parameters decrease from 19%, 390 ms, and 800 Ω m upstream to 3%, 160 ms, and 10 Ω m downstream, respectively for effective porosity, relaxation time, and resistivity. The transmissivity and specific yield estimated from the decline of MRS longitudinally also vary from upstream to downstream. The combined use of surface geophysics constrained by lithological borehole logs provides vital insight into groundwater replenishment in this dryland environment.

An Africa Little Known in Brazil: Societies Between the Sahel and the Niger Basin, or the Mandinga and Songhay States

An Africa Little Known in Brazil: Societies Between the Sahel and the Niger Basin, or the Mandinga and Songhay States

Signature of teleconnection patterns in river discharge within the Niger Basin

Signature of teleconnection patterns in river discharge within the Niger Basin

Developing objective dry spell and drought triggers for drought monitoring in the Niger Basin of West Africa

Developing objective dry spell and drought triggers for drought monitoring in the Niger Basin of West Africa

Reservoir operation simulation for existing and planned hydropower projects on the Niger and Benue catchments in Nigeria

In 2015/16, a hydropower site screening study was undertaken in Nigeria on the main stem of the Niger River and in the Benue River basin. The study assessed small (5-20 MW installed capacity), medium (20-100 MW) and large projects (> 100 MW) focusing on hydropower sites with potential multipurpose benefits. In the final stage of the study, three sites (two medium and one large project) were recommended for future development by the Government of Nigeria in liaison with the Niger Basin Authority (NBA). The study covered: Simulations of energy production and water demand satisfaction using the MIKE HYDRO Basin software. The modelling approach was based on maximizing energy production and maintaining a target mean load factor. (1) Impacts of reservoir development on hydropower production benefits, downstream flow variability, navigation downstream for three time horizons: current, mid development and maximum potential development. (2) Sensitivity analyses of water availability risks for hydropower generation for the three selected sites considering possible future abstractions and projected climate change. (3) Optimization of the use of the River Niger’s White flood in Nigeria and study of the augmentation of the Kainji HPP in order to mitigate the potential future production losses due to upstream developments/abstractions outside Nigeria.