The study was conducted on multi criteria analysis for assessment of vulnerable areas to flood hazard in the upper river Kaduna basin, north-central Nigeria. Six (6) criteria; topography, slope, landuse and landcover, stream density, soil types and mean annual rainfall of the area were integrated for assessment of vulnerability of flood hazards in the basin. Data on each of the six (6) factors were acquired, processed, weighted (using Analytical Hierarchy Process (AHP)) and overlain using weighted sum module of ArcGIS 10.5 software. The output map was classified into four (4) classes of vulnerability, that is, highly vulnerable, vulnerable, marginally vulnerable, and safe zones. The result revealed that parts of Bauchi, Kano, Katsina and Plateau States that were within the basin were not much vulnerable to flood hazards. However, close to half of the land area (48.43%) in Kaduna State were found to fall in either highly vulnerable or vulnerable zones, while 88.9% of the land area of Niger State within the Basin was also either highly vulnerable or vulnerable. Kaduna metropolis (comprising of the entire Kaduna North and South LGAs as well as parts of Igabi and Chikun LGAs), which is the most populated town within the entire basin was found to be more vulnerable to floods than any of the other LGAs in the State. In Kaduna South, 86.87% were highly vulnerable, almost half (44.88) of the land area of Kaduna North were also highly vulnerable. It was concluded that rainfall, topography urbanization and land-use were the main factors responsible for flood hazards. Proper land-use management and monitoring as well as sustainable utilization of the entire River Kaduna basin were recommended to minimize the constant occurrence and effects of floods in the area.

This study was carried out to apply satellite- based climatic data in geospatial environment to downscale climatic data into smaller political units and to generate and analyse thematic maps of climatic variables in Gombe State. Spatial climatic data on rainfall, minimum and maximum temperature were obtained from DivaGIS climatic data, while water vapour, solar radiation and wind speed were derived from the WorldClim climatic data. Monthly climatic records from 1981-2021 in twenty-four points evenly spread across Gombe State on rainfall, minimum/maximum temperature and relative humidity were obtained from NASA Power Project to generate the trends and seasonal patterns of temperature and rainfall. Daily climatic records of rainfall were also acquired from globalweather climatic data between 1979 and 2013 and processed to derive the values of rainfall indices using Nieuwolt formula. The monthly climatic records were processed using the kriging module of ArcGIS to transform the point climatic data to spatial data. The result revealed that rainfall in Gombe State occurs mainly between May and September with the peak in August, while the trends in rainfall was decreasing at the southern and northern parts of the state but increasing at the central region. Rainfall onset occurs in the 1st or 2nd week of May in the south, but late (1st week of June) in the north. Rainfall cessation at the central and northern parts of the state occurs in the 3rd or 4th weeks of September, while the southern part experiences late cessation between the 1st and 3rd week of October. The LRS ranges from 95-111 and 160-175 days in the northern and southern parts respectively. High relative humidity was recorded between May and October with the peak in August. Spatial patterns of solar radiation and wind speed were also generated and analyzed. Awareness of the use of satellite based climatic data and geospatial techniques for downscaling climatic data were recommended in order to ease the problems of lack or inadequate climatic data for spatial mapping. Causal factors for the spatial patterns of climatic variables in Gombe state was suggested for further studies