Expressing the rate of energy dissipation either within a basin or in a downstream manner is important in understanding occurrence and association between various morphological variables. This study focuses on the downstream variation in stream power and its relationship with morphological variates along the main channel of River Ona, Ibadan, Nigeria. River Ona stretches for 20.5 km downstream of Eleyele Dam. Twenty‐seven (27) points were sampled along this stretch. The 27 points were averaged into nine (9) reaches. At each cross‐section, channel characteristics were observed and measured. These include: width (W), depth (D), velocity (V), slope (S), Cross‐sectional area (A), discharge (Q), total stream power (TSP), specific stream power (SSP), width‐depth ratio (W/D), hydraulic radius (R) and wetted perimeter (P). This study confirmed that the influence of a dam present upstream of a river channel significantly alters the behaviour of slope and this in essence affects the distribution of energy along the river channel. Slope produces a logarithmic relationship with increasing distance downstream (Y = ‐32.79‐0.70InS, r = 0.70, r2 = 0.49, p < 0.05) while there was no significant relationship between Q and distance downstream.