The Congo Basin holds the world’s second largest tropical forest on Earth; a diverse landscape of montane forests, dense lowland forests, seasonally-inundated swamps, forest-mosaics, and arid savannahs. Unfortunately, in the wake of a projected four-fold growth in human population, large regions within the Basin face dramatic increases in deforestation rates as forests are cleared for croplands, timber, settlements, and charcoal.
A new research project underway by the Sustainable Agroecosystems Group at the Swiss Federal Institute for Technology (ETH Zurich) aims to monitor the carbon biogeochemistry of a pristine river within the Congo Basin in order to establish a baseline against which to assess future human impacts. The group selected the Ruki River, a large centrally-located tributary to the Congo. The Ruki represents only 5% of the total Congo Basin by area but is uniquely blanketed by homogenous pristine lowland forest land-cover. Although the 5% basin footprint might seem small, it is still a massive river, draining an area 6 times the size of Belgium (188,800km2).
As a first step, the group set up a gauging station to continuously measure discharge of the Ruki River 1km upstream of the RukiCongo confluence. At the gauging station, the river width is more than 500m and average flows are about 4500m3 s–1. Flow data generated by this gauging station was then used to quantify fluvial export of carbon, nutrients, greenhouse gases, and sediment.