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The acute shortage and scarcity of lands for suitable waste disposal is rapidly becoming a critical growing potential problem in most urban cities in developing countries of the world, and several fast-growing cities in Nigeria are not exempted from this menace. In this study, geographic information system (GIS) and analytic hierarchy process (AHP) are combined to select the most suitable landfill location in Lokoja, Nigeria. The landfill site selection criteria considered include proximity to major road, powerline, water body, landfill areas and built-up area. GIS was used to digitize spatial features related to unsuitable landfill site. A total of 19 candidate landfill sites were identified from GIS analysis. AHP model was developed from the GIS result as multi-criteria decision tool in evaluating each candidate site so as to choose the best appropriate landfill site. AHP model rated candidate site 11 located along Jimgbe road has the most preferable site to locate a landfill in Lokoja with an approximate area of 3.4204 km 2 ; the distance from the minor road, nearest water body, powerline and built-up areas to the location is 210.50 m, 1408.20 m, 1810.80 m and 205.61 m, respectively. Also, the model rated candidate site 16 located along 500 housing units as the least preferable site to locate a landfill in Lokoja. The characteristic features of the site location as obtained from GIS analysis include an approximate area of 2.5680 km 2 at an approximate distance of 2430.75 m, 594.04 m, 1980 m and 200.68 m from the major road, water body, powerline and built-up areas, respectively. This result will greatly serve as guide in landfill site selection in major urban states of other developing countries.

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Flood is one of the highly pronounced ruinous naturally occurring environmental hazards in which human lives and properties are gravely endangered. This study assessed areas prone to flood in Ibadan City, Nigeria. The study applied two multi-criteria analysis approach-Analytical Hierarchy Process (AHP) and the Fuzzy Analytical Hierarchy Process (FAHP) with the aid of GIS. Ten geomorphological physical characteristics agreed upon by experts as the major factors influencing the susceptibility of an area to floods formed the criteria maps used in this study. The natural breaks and geometrical interval clustering techniques were utilised to group the final flood-prone area maps into five categories-very low, low, moderate, high, and very high. The result indicated that over 50% of the study area either have low or moderate susceptibility to flooding. The clustering techniques showed some slight differences in the flood classifications where natural breaks consistently grouped more areas into the "very high" category and relatively fewer areas to "very low" category in comparison to the geometrical interval technique. Overall, at least 451 km 2 (about 15% of Ibadan) is highly or very highly prone to floods, and these areas are mainly concentrated in the urban and semi-urban regions of the study area. The findings and maps developed in this study would adequately serve as a planning guide for the policymakers on urban development and flood risk management to achieve sustainable development and management. K E Y W O R D S analytical hierarchy process, clustering techniques, flood-prone areas, fuzzy analytical hierarchy process, GIS, multi-criteria analysis 1 | INTRODUCTION Natural disasters have terrifyingly been escalating in many parts of the world, and their impacts have become one of the most subjects of concern in recent times. Such cataclysms include soil erosion, earthquakes, wildfires, and floods, whose occurrences customarily result in immeasurable losses of lives and properties every year