Geometrical Computation of River Omi South Western Nigeria

Hydraulic geometry deals with variation in channel characteristics in relation to variations in discharge. Two sets of variations are important which are variations at a particular cross section (at-a-station) and variations along the length of the stream (downstream variations). Characteristics responsive to analysis by hydraulic geometry include width (water-surface width), depth (mean water depth), velocity (mean velocity through the cross section), centroid, slope, and channel friction. Changes in river geometry are defined by cross section. The geometrical computation was achieved by surveying using GPS RTK, calibrated rope, measuring tape, ranging rod and topographical map. The result obtained showed that the hydraulic radius increases downstream with values ranges from (9.99 - 34.55) cm for upstream and downstream respectively. The slope varies from 0.038 for upstream and 0.002 for mid and downstream respectively. Centroid value on omi river varies from 0.025-0.53. The highest value was obtained at upstream while downstream value was 0.042.