FLOOD RISK MONITORING AROUND PART OF THE NIGER DELTA BASIN OF NIGERIA

Abstract

Different environmental geo-hazard events on the society are seriously manifesting by the extent of flood which that influenced by climate change variables. This research is tailored on investigating the dynamics of frequently occurring natural flood disaster. Recently launch Sentinel-1 SAR satellite constellation was adopted for temporal feature extraction and extent assessments over the study area. Methodology adopted involves Binarization (Thresholding) techniques, suitable pixel intensity through Band Maths to calculate and extract water accumulation with-in the Area of Interest (AOI). Result obtained shows that, number of scenes has no influenced on the expected outcome with a gradual increase in flood geo-hazard from September, 2017 (10.49345%) to May, 2018 (12.6057%) and a slight drop in May, 2019 (11.47714%).  Flood events possess a gradual progressive increase over time with that of October, 2022 as high as (12.29319%). It was observed that May, 2018 have the highest percentage of water catchments area (12.6057%) with the highest percentage of flood geo-hazard, then October, 2020 (12.29319%), then May, 2019 (11.47714%) and September, 2017 (10.49345%). Rate of water accumulation over the AOI was predicted with an extension to October, 2022.  It was evident that flood event is a gradually accumulated and continuous geo-hazard event. Being a continuous phenomenon, over a period of time, it however flooded the solid part of the earth surface where most human activity such as places reserves for farming and dwelling. It could be seen that flood rate is not constant because other activities could also contribute immensely towards increasing flood geo-hazard. The recommended that study of geo-hazard events should be investigated at an interval adopting a space base approach with numerous advantages.