Geo-Spatial Assessments of Flood Disaster Vulnerability of Benue and Taraba States

Rainfall intensity, low terrain and the release of water from Lagdo Dam upstream of River Benue in the Republic of Cameroon have recently subjected the floodplains of River Benue to frequent and devastating flood occurrences. The havoc wrecked by the 2012 floods in this region and downstream of the Niger in Nigeria has challenged the government and her relevant agencies to seek for reliable and up-to-date data for proper flood control and management strategies. Suggestions were made to the government to relocate some of the settlements that are close to River Benue as well as those that are vulnerable to the floods, but earlier resettlements decisions in Nigeria were based on manually generated data which were subject to inaccuracies as a result of the use of incompetent hands for data generation and human influence, hence, the need for automated techniques such as remotely sensed data and GIS technique for data generation and decision making on the identifications of flood vulnerable areas and the communities that are subject to relocation. ArcGIS 9.3 was used in this paper to generate, classify and analyze the Digital Elevation Models (DEM) of Benue and Taraba States for assessment of flood vulnerability of the area. The coordinates of five hundred and seventy six (576) communities were also obtained by the use of GPS which were linked to the DEM map for identification of the communities that are located in flood vulnerable areas. Five and ten kilometers buffer as well as three and five kilometers buffer were generated along River Benue and the major tributaries respectively for immediate and long term flood management and planning. The study revealed that out of the total land area of 92.84km2 of the two states, the Benue Basin which was classified as “highly vulnerable” to floods covered 48.69%, while the plain that was classified as “vulnerable” comprised 28.24%. Hence, a total land area of 77.71% of the two States is prone to flood. However, Benue State was discovered to be more vulnerable to flood than Taraba State as the state has 98% of its land area either highly vulnerable (Benue Basin with 77.37%) or vulnerable (Plains with 20.93%). The communities (including their names) that are located within each of the vulnerable classes and within some specific buffer zones were also identified and analyzed. A simple database was generated from the DEM data while spatial analysis based on the database for decision making was demonstrated. It was recommended that all the stake holders should embark on the use of remotely sensed data and GIS techniques for flood management and control.