In Nigeria, the climate in recent years has witnessed significant variability across the various ecological zones due to climate change. Thus, the objective of this study was to analyse the 21st century trend of water yield in river basins of Guinea and Sudano-Sahelian ecological zones, Nigeria. The data and computation were done using KNMI Climate Explorer. The coordinates of the basins were used to derive the annual and seasonal water yield. Projections were produced for near-term (2019-2048), mid-term (2049-2078) and long-term (2079-2100) using ensemble mean of CMIP5 under RCP2.6, RCP4.5 and RCP8.5. Findings revealed that water yield during dry season demonstrates decreasing range of (-0.05 to-0.1 mm/day). It was observed that the decrease were only significant for RCP8.5 but not under middle and low emission trajectories. As for wet season, it reveals significant increasing trends at 0.05 significant levels with respect to RCP8.5 but not significant in low and middle emission scenarios. Regional trend analysis of average annual water yields reveals no significant positive trends for all the RCPs. This is to say that despite the projected increasing pattern of average annual water yield observed over Guinea and Sudano-Sahelian ecological zones, incidences of water crisis cannot be ruled out. Contribution/Originality: This paper's primary contribution is finding that river basins of Guinea and Sudano-Sahelian ecological zones of Nigeria will be significantly affected by the anthropogenic climate change at highest emission trajectory. The result can act as guidelines for strategic planning against water crisis as envisaged by the projection. 1. INTRODUCTION Climate projection is usually a statement about the likelihood that something will happen several decades to centuries in the future if certain influential conditions develop. Scenarios however, represent alternative possible ways in which the future may unfold [1]. Globally, it is estimated that by 2050 between 150 and 200 million people could be displaced as a consequence of phenomena, such as sea level rise and increased extreme weather events [2-5]. Furthermore, the Global Environmental Outlook's Baseline Scenario OECD, (2012) cited in Adefisan [6] projects increasing strains on water resources through 2050, with an additional 2.3 billion people expected to be living in areas with severe water stress, especially in North and South Africa and South and Central Asia. WWAP (United Nations World Water Assessment Programme) [7] predicts the world could face a 40% global water deficit by 2030 under a business-as-usual (BAU) scenario. Africa's rising population is driving demand for water under

River Chanchaga is the major source of drinking water in Minna, Nigeria. This river has been a medium to an increasing pollution loads from contaminated runoff from different land uses degrading aquatic ecosystem and water quality in the river.This paper investigates the threat of anthropogenic influence on river environment and aquatic ecosystem distortion of River Chanchaga, Minna, Nigeria. Field work which include interview and observation methods were used to collect data on effect of anthropogenic and eutrophication along the study area. A total of Two Hundred and Fifty (250) people accounting for 0.5% of the total population were interviewed, making it eight per each community in thirty settlements along the study area. Physical observation of deforestation around sample sites spatially distributed along River Chanchaga depicted in Figure 2 was carried out to study mining activities, farming practice, crop types, and fallow duration to generate the mean and percentages of different anthropogenic activities along the study area. The findings revealed that deforestation is links to high demand for fire wood, lumbering, irrigation farming bank-side mining for sand and gold as depicted in Plat 1 and 2. Eutrophication at the upper course of river is links to high inflow of agricultural wastes and seasonal nature of the river from site A to C evident from Table 4 and constant flow from site C to K as a result of released water from Tagwai Dam that keeps (site C, the confluence of River Chanchaga and River Numui) middle and lower courses of River Chanchaga with sustainable moving water. The result further indicated that continue increase of pollution has a direct relationship to an increasing level of human activities like deforestation, mining activities and agricultural practices along the study area. The result also shows that there is decline in fallow duration as indicated in Table 1 and increase environmental related issues such as soil erosion, water floor (depth) reduction and distortion of river morphology of the study area. It is therefore recommended that the identified anthropogenic activities that lead to pollution and eutrophication such as river-side deforestation, irrigation farming, mining and other related environmental problems should be regulated and discourages to avoid further increase of pollution and distortion of river environment of the study area.

A developing nation like Nigeria should be much concern on environmental management particularly in the area of drinking water, air, soil or general ecosystem. Sediment inflow has become public concerns on aquatic life and habitat loss as well as fragmentations of biodiversity of River Chanchaga. The study assessed the effects of human induced sediment inflows on habitat quality in River Chanchaga. The inhabitant population data, rainfall data and remote sensing data were collected to determine sediment inflow and land use cover of the study area. A total of 250 people accounting for 0.5% of the total population were interviewed, making it eight per each community in thirty communities along the study area. The findings of the study revealed a significant correlation between rainfall and runoff at r = 0.991 accounting for 99% indicating strong positive relationship between them. Pearson correlation is 99% with remain 1% for other parameters like wind, institutional and industrial activities accounting for negligible percentage that are responsible for sediment inflow of River Chanchaga as depicted in Table 3. The implication of this is that the higher the mean monthly rainfall, the higher the runoff volume in River Chanchaga, which may result into subsequent increase of sediments inflow into the river. The result from the study is that land use covers have been affected by population increase, which have direct impact on soil erosion that influences sediment inflow into the study area. The study recommended that anthropogenic activities that lead to generation and transportation of huge volume of debris and sediment loads along River Chanchaga should be regulated to control or reduce aquatic habitat quality damage and to ensure making good use of aquatic resources. There should be programme to enlighten general public on implications of indiscriminant human activities that can affect habitat and water quality along the study.

River Chanchaga is the major source of drinking water in Minna, Nigeria. This river has been a medium to an increasing pollution loads from contaminated runoff from different land uses degrading aquatic ecosystem and water quality in the river.This paper investigates the threat of anthropogenic influence on river environment and aquatic ecosystem distortion of River Chanchaga, Minna, Nigeria. Field work which include interview and observation methods were used to collect data on effect of anthropogenic and eutrophication along the study area. A total of Two Hundred and Fifty (250) people accounting for 0.5% of the total population were interviewed, making it eight per each community in thirty settlements along the study area. Physical observation of deforestation around sample sites spatially distributed along River Chanchaga depicted in Figure 2 was carried out to study mining activities, farming practice, crop types, and fallow duration to generate the mean and percentages of different anthropogenic activities along the study area. The findings revealed that deforestation is links to high demand for fire wood, lumbering, irrigation farming bank-side mining for sand and gold as depicted in Plat 1 and 2. Eutrophication at the upper course of river is links to high inflow of agricultural wastes and seasonal nature of the river from site A to C evident from Table 4 and constant flow from site C to K as a result of released water from Tagwai Dam that keeps (site C, the confluence of River Chanchaga and River Numui) middle and lower courses of River Chanchaga with sustainable moving water. The result further indicated that continue increase of pollution has a direct relationship to an increasing level of human activities like deforestation, mining activities and agricultural practices along the study area. The result also shows that there is decline in fallow duration as indicated in Table 1 and increase environmental related issues such as soil erosion, water floor (depth) reduction and distortion of river morphology of the study area. It is therefore recommended that the identified anthropogenic activities that lead to pollution and eutrophication such as river-side deforestation, irrigation farming, mining and other related environmental problems should be regulated and discourages to avoid further increase of pollution and distortion of river environment of the study area.