This study used annual rainfall records from three stations within the North East Arid Zone of Nigeria for the period (1957-2017) to measure the extent of the rainfall recovery by comparing the drought decades and post drought decades rainfall patterns. Monthly rainfall records from Potiskum, Maiduguri and Nguru Stations were used. Descriptive and inferential statistical tools were employed in analysing the data. The findings of the study revealed a significant year-to-year variability in rainfall characteristics around 61 years (1957-2017) averages. The variability was large in 1970s up till 1990s, and lower in 1960s and from 2000 to 2018. Decreasing trend in annual rainfall amount was observed during the study period while a stability in onset and cessation dates were observed. The differences between 1957-1986 and 1987-2017 climatic season were found to be statistically insignificant. The study concluded that the reported rainfall recovery from drought is statistically insignificant and the observed long term mean trend revealed a decreasing trend. Therefore, the theory of Sahel rainfall recovery can be better termed as a ‘’break of the series of drought or decline in frequency and magnitude of occurrence of drought’’ The research recommended the continuations with the drought adaptation and mitigation strategies adopted by local population, decisions makers and organizations following the series Sahelian droughts of 1970s and 1980s.
Nzoia River Basin is one of the regions that is highly vulnerable to climate change in Kenya. Many attempts have been made to identify and quantify the impact of climate change on socio-economic sectors and ecosystems using global studies resulting into recommendations on policy changes aimed at generating sustainable mitigation and adaptation strategies. This top-down approach by using global studies lacks the required local and regional climate change specificities to address the regional and local climate change challenges. Temperature is one of the most important components of the climatic parameters widely measured as a starting point towards the apprehension of climate change courses. This study aims at filling the top-down approach knowledge gaps in Nzoia River Basin by assessing temperature variability and trends at three stations for the period 1979 to 2014, using Linear regression analysis and Mann-Kendall statistical test. Monthly maximum and minimum temperature data for Kitale, Kakamega and Eldoret stations was obtained from Kenya Meteorological Department, Nairobi, Kenya. The main findings reveal that Kakamega has highest temperatures, followed by Kitale and the lowest temperatures are found at Eldoret. This trend seems to go with altitude as the lowest temperatures are found at highest altitudes and highest temperatures at lowest altitudes. There are significant increases in annual temperatures for Kitale and Kakamega stations, with Kitale showing annual maximum temprature rising at 0.0006260 C/year; annual minimum temperature rising at 0.0011630 C/year and the annual mean temprature rising at 0.0008940 C/year. Kakamega shows annual maximum temperature rising at 0.0007710 C/year; annual minimum temperatures rising at 0.0004710 C/year and the annual mean temperatures rising at 0.0006230 C/year. Eldoret shows falling maximum temperature at - 0.002020 C/year; rising minimum temperature at 0.0008130 C/year and falling mean temperatures at - 0.001420 C/year. The results for Kitale and Eldoret stations show statistically significant trends whereas those for Kakamega station were statistically insignificant. Eldoret annual minimum temperatures are rising faster than the maximum whereas in Kakamega it’s the annual maximum temperatures that are rising faster than the minimum. Kitale and Kakamega show annual mean temperatures rising at about 0.10C per century which compares well with IPCC Third Assessment Report estimated global warming rate of 0.6 0C during the twentieth century and other studies from the African continent and East African region.
Soil erosion is still one of the most important land problems and it is linked to land use and land cover changes. These have negative effects on land resource which ultimately affects agricultural productivity and water quality. Local monitoring systems constitute an almost compulsory component of any program or project dealing with sustainable management of natural resources. The purpose of this study was to identify soil erosion monitoring indicators in Kuresoi South, Kenya. The study was comprised of a total representative sample population of 68 respondents from Kuresoi south catchment which was achieved using Nassiuma coefficient of variation formulae. Our findings reveal a positive significant relationship between soil erosion monitoring indicators and natural resource management. Taken together, soil erosion monitoring indicators can be used in detecting change over time in soil resource.
Igueben is located in the central of Edo State, Nigeria. It has neighboring towns; Ogwa, Ugbegun, Ugiogba, Ebelle, and Ekpon. These towns have the same aquifer but significantvariations in the water table. However this study is intended to unravel the salient ancient hydrological processes that occurred in the study area which resulted in this variation. Vertical electrical sounding (VES) data and borehole data of the area are integrated to generate geo-electrical resistivity section of the area, to identify the aquifer trends, body, and shape to re-construct the palaeo-sedimentation processes of the aquifers that underlie Iguebe and the neighboring towns. The inversion model result for the seven VES conducted in the study area show that the curve types are HQA, AHA, A, AHA, AHA, HAQ, and AQA, respectively. These curve type suggested that the aquifer type is anarenite sandstoneaquifer that has been transported from a long distance. The geo-electrical pattern and shape show that Igueben and Ogwa (shallow marine) are the points of deposition from where other nearby towns (Ugbegun, Ugiogba, Ebelle, and Ekpon) sourced their aquifer by gravity settling from suspended sediments in water body into adjacent deep marine environment (Ugbegun, Ugiogba, Ebelle, and Ekpon).The study showed that Igueben and Ogwa are the hydraulic-head of the aquifer in the study area. The geological processes that had occurred in the study area during sedimentation are responsible for the variation in the water table in the study area.
In the past decade, it has been reported that water quality of rivers are deteriorating increasingly. In this study we examined the state of River Ossiomo to assess the current health of the river for a period of 24 months from April 2019 to March 2020, then July 2020 to May 2021 in three well marked out stations. The study was to determine the relationship between environmental variables and fish species assemblage in the river. From the results of the physico-chemical variables, the mean values of pollution indicating physico-chemical variables such as sulphate (1.26+0.32mg/l) and total suspended solids (TSS) (5.53+1.89mg/l) were higher in station 2. On the other hand, pH (5.94+0.48), DO (8.64+1.57mg/l), turbidity (7.48+7.63NTU), TDS (29.64+14.65mg/l) and phosphate (0.43+0.31mg/l) mean values were highest in station 1. Conductivity (70.87+26.42µS/cm) and nitrate (0.49+0.34mg/l) mean values were highest in station 3. Further, dissolved oxygen (DO) was higher in station 1, the reference station. The analysis of variance (ANOVA), we performed for the physico-chemical variables revealed that temperature, conductivity, DO, total dissolved solids (TDS), alkalinity, TSS, sulphate, phosphate and nitrate were significantly different among the three stations sampled (P<0.05), while pH, BOD and turbidity were not significant among the three stations sampled (P>0.05). The result of the principal component analysis showed that conductivity was positively associated with station 3, and temperature, TDS and alkalinity were negatively associated with stations 1 and 2. A total of 2,324 fish individuals belonging to 29 taxa were recorded in the entire study period. Station 1 harbours more fish species (1018), followed by station 2 (809), and we recorded the lowest number of fish individuals in station 3 (497). Auchenoglanis occidentalis was the most preponderant fish species probably occasioned by its level of adaptation to prevailing environmental conditions in the study river. The least abundant fish species was Synodontis eupterus.The canonical correspondence analysis we used in visualizing the relationship between fish species and physico-chemical variables showed that fish taxa such as Distichodus brevipinni, Cteropoma kinsleyae, Tilapia zillii, Malapterarus electricus, Mormyrus engystoma, and Synodontis nigita that were positively associated with pollution indicating physico-chemical variables were suggested as indicators for monitoring riverine health in the Niger Delta area of Nigeria. We recommend that more detailed studies should be carried out in River Ossiomo to confirm this result. However, this study serves as a baseline study in the present study area.