Urban Gully Development in Southwestern Nigeria

Copyright © 2013 Aderemi Adediji, Matthew Olomolatan Ibitoye. This is an open access article distributed under the Creative Com-mons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This study examined the development of urban gullies in a part of Southwestern Nigeria. This was done with a view to determine the volume and amount of sediment loss from the 1st and 2nd order gullies in a cascade system. Twenty (20) towns were randomly selected from where thirty (30) gully systems comprising forty (40) 1st order and five (5) 2nd order gullies were measured with Tape and Total Station (TS). The gully dimensions measured include gully lengths, depths and cross sectional areas. The core samples were also taken from the study gullies for the determination of the soil bulk density. The results showed that the mean volume of soil loss from the 1st order and (2nd) order gullies in the study area are 1612.633 m3 and 1629.922 m3, respectively. The weight of the estimated sediment loss from the 1st order and 2nd order gullies are 2661.621 and 2657.318 tonnes, respectively. The result further showed that the total soil loss of 119661.442 tonnes was obtained from the study gullies and that the 1st order gullies accounted for 87 % (106,375 ton-nes) of the total soil loss. This was an indication of soil degradation in the area