DIFFERENCES IN MORPHOMETRIC PARAMETERS ACROSS THE VARIOUS SEGMENTS OF THE CROSS RIVER BASIN

Although a drainage basin is often described by a single set of whole-basin parameters, its component segments, or sub-basins, can differ substantially in morphometric character, with direct consequences for how hydrologic hazard is distributed across the catchment. This study examines the differences in morphometric parameters across the seventeen third-order sub-basins, or segments, of the Cross River Basin (CRB), a transboundary catchment of approximately 51,892 km² in southeastern Nigeria and western Cameroon. Descriptive variability statistics (mean, standard deviation and coefficient of variation) and paired t-tests were applied to linear and areal parameters extracted from a 2020 ASTER Digital Elevation Model. Results show that the seventeen segments differ most sharply in size-related parameters, with basin area exhibiting a coefficient of variation (CV) of 53.6%, total stream length 49.2%, and number of streams 48.5%, the largest segment (4,769.49 km²) exceeding the smallest (826.94 km²) by a factor of nearly six. Shape-related parameters occupy an intermediate position (CV between 19% and 36%), while drainage density (CV = 11.4%) and length of overland flow (CV = 10.7%) are comparatively uniform across segments. A paired t-test comparing first-order and second-order mean stream length across the seventeen segments returned statistically significant difference (t = 3.66, p = 0.002), while a paired t-test comparing first-to-second-order and second-to-third-order bifurcation ratios did not reach significance (t = 1.69, p = 0.111). On the strength of this evidence, the null hypothesis of no significant difference in the morphometric parameters of the Cross River Basin's segments is rejected. The findings demonstrate that the CRB is morphometrically heterogeneous at the sub-basin scale, most markedly in size and network complexity and least markedly in drainage density, a pattern with direct implications for how the basin's hydrologic response and flood risk should be assessed and managed on a segment-by-segment rather than whole-basin basis.