Vulnerability assessment of structures along river channels in Oyo metropolis, Oyo State, Nigeria

This study makes use of Remote Sensing and Geographic Information System techniques to assess the vulnerability of structures along river channels in Oyo metropolis. The vulnerable rates were classified into High, Medium and Low using 30m, 45m and 60m buffer distances from the middle of the river channels while network analysis was also carried out to attend to any emergency operation. To achieve this feat, a geospatial database was designed and created with various analyses carried out on the entities extracted from the satellite image of the study area. Such analyses include, buffering to categorize the vulnerable zones into the various classes, network analyst menu of ArcGIS 10.2.2 was employed to find the best route from the Fire Service Station to the point of accident and also an alternative route in case of a barrier or barriers on the best route. This showed that a total of 881 buildings will be affected in any instance of flooding that is within 60m from the middle of the river channels in the study area. 399 buildings fall in high vulnerable zone accounting for 45.29% of the buildings examined for vulnerability in the study area, 245 buildings fall within the moderately vulnerable zone accounting for 27.81% and 237 buildings fall within low vulnerable zone at 26.90%. The best route from the Fire Service Station to the point of accident is gotten to be 2.3 Km while the alternative route is 2.7 Km when a barrier is placed on the best route during rescue mission indicating 0.4 Km difference between the two routes. Maps, tables and a chart were produced for various results.