According to the most recent measuring record at Boma station, the average flow rate of the Congo River is registered as 40615m³/s. It is ranked as the second largest river of the world, after the Amazon.
The Congo River enjoys limited impacts from the seasonal fluctuations because of the basin across over both northern and southernsides of the Equator. The earliest observation was done up to 1902 at the upstream Leopoldville firstly by the Institute of Development Studies of the Lower Congo. It was until 1953, the flow rates of Congo River are measured for the first time. The study revealed that the average flow rate of the river is 38155m³/s, with a highest record up to 66665 m³/s in 1908 and the lowest down to 21873m³/s in 1905.