Hydrogeomorphic Characteristics of Urban Flood Triggers in Gombe Town, Nigeria as Monitored in 2014

Abstract

Urban flooding has become a monumental yearly disaster in many of the world’s cities and Gombe town in particular. This paper focused on some hydro-geomorphological characteristics that influence flooding in Gombe town. Statistical methods and geographic information techniques were used for the assessment. The result revealed that the highest API of 166.62 mm occurred on the 5/9/2014. The rainfall amount was 92.5mm for a duration 48 minutes, average rainfall intensity was 115.63, stage height (1.42m), average flow velocity (0.98m/s), and instantaneous discharge of 9.47m3 /s. This corresponds with the flood disaster that occurred in Gombe town on the same date (5/9/2014). On the other hand, the least API of 18.12 mm occurred on the 18/6/2014. The rainfall amount was 1.2mm for 62 minutes, average rainfall intensity was 1.16, stage height (0.30m), average flow velocity (0.24m/s), and instantaneous discharge of 0.49m3 /s. findings also showed that very steep slope covered 2.4537km² (1.78%), steep slope covered 3.60235km² (2.61%), moderate slope (0.735574km² or 0.53%), gentle slope (131.106km² or 94.89%) and flat areas (0.259854km² or 0.19%). The study recommended flood resilience technology, provision of adequate urban drainages and proper storm water management.

Keywords: Drainage density, flow accumulation, rainfall, urban flooding