The study assesses the variation in depth along the main channel of Otamiri River, in Rivers state, Nigeria. Quasi-experimental (field survey) research design was adopted for the study, as it involves observation on the morphometry parameters of the tributaries of Otamiri river. Primary data were collected through tape, ranging pole, float, and Stopwatch, while drainage maps and topographic map become secondary sources of data. The sample frame for this study is total length of all tributaries of Otamiri-river basin, in the study area. The total length of the tributary streams is 320 kilometers, the data were collected at interval 1 kilometre since total length is 320 kilometres, then 320 divide by 1, therefore the sample frame is 320 Sampling Station. Analysis of variance (ANOVA) was used in testing the various conjectural statements at 5% level of significance for acceptance or otherwise. Findings revealed that, there is variation in a significant variation in the depth along the main channel of the Otamiri river basin in the Southern Nigeria. From the findings, it was inferred that geomorphic and morphometric variations exist both with the main trunk of the Otamiri river as well as the major tributaries. These variations could be a function of temporal variation in the input factors as well as process modifications along the river channel and its basin area. Thus, the researcher recommends, adequate and periodic channelization through dredging of the downstream River channel as to improve channel capacity in order to reduce the menace of flooding that causes displacement of settlement and other human meaningful activities within the area concerned.