Streamflow and sediment load assessment from 1950 to 2006 in the Usumacinta and Grijalva Rivers (Southern Mexico) and the influence of ENSO

Variations in water and sediment discharges of rivers can affect the human activities and in long-term modify the landscape. The climatic effect such as El Niño-Southern Oscillation (ENSO) is a first-order factor controlling the streamflow and sediment load however, its behaviour and links with water and sediment discharges are not fully known. We evaluate the response of the streamflow and sediment load in relation to ENSO within the largest fluvial system of Mexico: the Usumacinta and Grijalva River basin. The two rivers that compose this basin joined together ~ 50 km off the Gulf of Mexico forming a basin of ~ 112,000 km2 that has an annual discharge of ~ 2678 m3 s− 1. We use data spanning of ~ 56 years from four gauging stations located at the low and middle reaches of the Usumacinta and Grijalva Rivers. The spanning of ~ 56 years of data of water and sediment load allowed us to detect the control exerted by the ENSO on these two processes. Our results indicate that when there is present either El Niño or La Niña, water discharge notably increases. In La Niña, however, river discharge in the Usumacinta and Grijalva is greater compared to that in El Niño. Our results suggest that both ENSO and the cyclonic activity of the Atlantic Ocean are a primary control on water discharge and sediment mobilization of the rivers of Southeast Mexico.