An uncontrolled sediment influx from the watershed upstream is a known threat to dam stability, while the pattern and amount of sediment yield are influenced by the predominant upstream land-use and land cover (LULC) types, precipitation amount, and intensity. Hence, the need to monitor sediment yield accumulation and its controlling factors in dam operation becomes crucial. In this paper, the Soil and Water Assessment Tool (SWAT) was used to assess the roles of land-use change, land cover area, and runoff on watershed’s sediment yield based on change detection analysis between 1975 and 2013 in the Kaduna Watershed (Nigeria), Western Africa. The SWAT standard procedures for the simulation of hydrological characteristics and sediment yields prediction were adopted. The datasets were calibrated for a period of 46 years and validated using 2015–2017 measured flow data, and suspended sediments concentration (SSC) acquired between March and October 2018. The model function was statistically determined using the Nash-Sutcliffe (NS), the coefficient of determination (r2) and the percentage of observed data (p-factor). The evaluation results of the SWAT model yielded NS, r2 and p-factor of 0.71, 0.80, and 0.86, respectively. These data suggest that the model performed satisfactorily for streamflow and sediment yield predictions. Findings suggest that the extinction of evergreen forests and a significant change in land-use from range grasses and forest to agriculture generic and residential types between 1975 and 2013, which resulted in surface runoff, sediment yield, and flow alteration. Evapotranspiration increased by 22.40% between 1975 and 2013. These changes have negatively impacted the watershed runoff by 56.00% and model sediment yield by 68.00% at the end of 2013. Thus, these variations can influence various human activities in the watershed, such as food security, livestock, energy production and water supply. It is hypothesized from the presented data that land use types exact a more dominant control on runoff and sediment yield than land cover area, although climatic influence may not be ruled out.

Over the years, sedimentation has posed a great danger to the storage capacity of hydropower reservoirs. Good understanding of the transport system and hydrological processes in the dam is very crucial to its sustainability. Under optimal functionality, the Shiroro dam in Northern Nigeria can generate ∼600 MW, which is ideally sufficient to power about 404,000 household. Unfortunately, there have not been reliable monitoring measures to assess yield in the upstream, where sediments are sourced into the dam. In this study, we applied the Soil and Water Assessment Tool (SWAT) to predict the hydrological processes, the sediment transport mechanism and sediment yield between 1990 and 2018 in Kaduna watershed (32,124 km 2 ) located upstream of the dam. The model was calibrated and validated using observed flow and suspended sediment concentration (SSC) data. Performance evaluation of the model was achieved statistically using Nash-Sutcliffe (NS), coefficient of determination (r 2 ) and percentage of observed data (p-factor). SWAT model evaluation using NS (0.71), r 2 (0.80) and p-factors of 0.86 suggests that the model performed satisfactorily for streamflow and sediment yield predictions. The model identified the threshold depth of water (GWQMN.gw) and base flow (ALPHA_BF.gw) as the most sensitive parameters for streamflow and sediment yield estimation in the watershed. Our finding showed that an estimated suspended sediment yield of about 84.1 t/ha/yr was deposited within the period under study. Basins 67, 71 and 62 have erosion prone area with the highest sediment values of 79.4, 75.1 and 73.8 t/h respectively. Best management practice is highly recommended for the dam sustainability, because of the proximity of erosion-prone basins to the dam.

Water constitutes a major environmental and public health concerns worldwide. A large proportion of global water consumption is sourced from surface water. The dependency level on surface water is higher in developing countries, especially in rural-to-semi-urban areas, where subsurface water is not accessible. Presented in this paper is a spatiotemporal and hydrochemical quality assessment of the spring-originated Landzun Stream in Bida, Nigeria; which is usually consumed in its untreated state. Water samples were systematically collected in eighteen locations along the stream channel in both rainy and dry seasons at an equidistance interval of 500m. On-site and laboratory measurement of important physical and hydrochemical parameters were carried out using standard procedures. Water temperature in the rainy season (34–37 °C) slightly exceeds measured values in the dry season (29–33 °C). 72.22% (rainy) and 83.33% (dry) of collected samples did not meet the odourless requirement for drinking water. Similarly, estimated percentages of 66.67 and 94.44 of collected samples in rainy and dry seasons respectively have a taste. Contrary to data in the rainy season, 89%, 11%, 67% and 56% of the dry season's samples were enriched in magnesium (Mg), lead (Pb), potassium (K) and iron (Fe) respectively above the 2018 World Health Organisation guidelines for drinking water. This study further established that seasonal variation plays a major role in altering the aesthetic surface water quality. The intake of untreated surface water is a vehicle for potential water-borne diseases and allergies, hence alternative sources of drinking water for the populace dependent on the Landzun Stream is recommended to reduce risks and possible dangers of consuming the stream water.

Many authors have identified climate variation impacts in Nigeria. However, the effects on water balance and water yield have not been thoroughly considered. Good knowledge of water balances is vital for sustainable water resource management in northern Nigeria due to high water stress and increased evapotranspiration compared to another part of the country. Hence, the study presents the first detailed climatic variation impacts on watershed water balance and water yield in north-central Nigeria. Soil and Water Assessment Tool (SWAT) was applied to predict the hydrological procedures. The Kaduna watershed (32,124 km2) calibrated and validated streamflow results were run independently using three land cover maps of 1975, 2000, and 2013. The model performance evaluation was statically attained using the coefficient of determination (r2), Nash-Sutcliffe (NS), besides the percentage of observed data (p-factor). The model evaluation result of r2 (0.80), NS (0.71), and p-factors of 0.86 indicated the model satisfactory performance evaluation of streamflow predictions. The streamflow estimation revealed Threshold depth of water (GWQMN.gw) as the most sensitive parameter. The findings discovered declined between 1975 and 2013 in precipitation, water yield, surface runoff (SURQ_mm), lateral flow (LAT_Qmm), deep aquifer (Deep_mm) by 4.2%, 37.3%, 56%, 15%, and 100% respectively, while shallow groundwater aquifer (GW_Qmm) experienced 10% decrease between 1975 and 2000 and appreciated by 6% between 2000 and 2013, evapotranspiration (ET_mm) increase by about 22.2% between 1975 and 2013. These results suggest considerable effects of climate variation in the watershed and call for further investigation to mitigate climate change influence.

Watershed assessment and developmental strategy demands precise measurement of the past and present land use parameters. Failure of Shiroro dam in 1999 and 2004 was attributes to upstream soil erosion. Hence, the study of land use change within the corridors of the reservoir for proper understanding of the watershed dynamics becomes very crucial. These dynamics was studied for a period of 38 years in the Kaduna watershed, north central Nigeria using Soil and Water Assessment Tool. The land-use land cover of the year 1975, 2000, and 2013 was reclassified into nine (9) classes in 1975 and eight (8) classes in 2000 and 2013, because of the extinction of Forest evergreen land use between 1975 and 2000.The classification shows the percentage land area of each of the land use type and the area in hectares. Findings revealed total extinction of the 0.03% of Forest evergreen land before 2000, in 2013 range grasses, forestmixed and wetlands-forested land-use have lost 23.92%, 2.06%, 3.77%, watershed land area respectively while, wetlands-mixed, agricultural land, water, barren and built-up land gained 0.18%, 27.81%, 0.53%, 0.02% and 1.25% respectively as at 2013. The lost in land-use area was attributed to human activities such as clearing and degradation of the natural landscape to another land-use type which posed a stern threat to the Shiroro dam downstream and the environment. If this persists it might contribute to global warming problems and land exposure to agents of erosion. Thus, appropriate best management practice of the watershed become essential.