Abstract
Understanding the natural and anthropogenic drivers that influence erosion and sediment transport is a key prerequisite for adequate management of river basins, where, especially in tropical catchments, there are few direct measurements or modeling studies. Therefore, this study analyzed the effect of human-induced land-use changes and natural ENSO (El Niño-Southern Oscillation) related changes in rainfall patterns on soil erosion and catchment-scale sediment dynamics with the SEDD (Sediment Delivery Distributed) model. In the 393 km2 Tonusco river basin, representative of tropical, mountainous conditions, daily rainfall data were used to quantify changes in rainfall erosivity and satellite images for the evaluation of cover factor changes between 1977 and 2015. The final model combined soil loss, calculated by RUSLE, with a sediment routing-based delivery ratio, that was calibrated and validated with data from the sediment load recorded at the basin outlet. The results detected a great reduction of the vegetation cover in the catchment during the last decade of from 79.5 to 29.5%, and the influence of important runoff and erosion events linked to La Niña episodes. Soil erosion rates were locally very high, of over 120 Mg ha−1yr−1, and sediment yields were estimated at the range of 6.17–8.23 Mg ha−1yr−1.
Highlights
El Niño” or “La Niña” Southern Oscillation (ENSO) years were detected quantifying Oceanic indexes based on the surface temperature of the Pacific Ocean southern region, such as Oceanic Niño Index (ONI) and Cold Tongue Index (Nct) and to confirm weather features related to these periods [55]
The Niño and La Niña periods are based on a threshold of +/−0.5 values of these indexes [19], and color codes of light blue, red, and dark blue were used in Figure 3 to indicate whether the precipitation (P), discharge (Q) and sediment load (W) of a particular year belong to a normal, El Niño and la Niña years
Phenomena very well Maximum values of rainfall were recorded in 1999, 2010, and 2011. These years are all La Niña years, marked in dark blue. It can be seen how these La Niña years are generally wetter compared to normal years, marked in light blue, while El Niño years, marked in red, are drier compared to normal years
Summary
Soil erosion is one of the greatest threats to the future of our agriculture and environment, and to our society. As Sposito [1] indicated, soil is a natural resource that cannot be taken for granted. Several recent studies warn about the risks of erosion for global soil resources, and water resources and ecosystems [2,3,4,5]. To tackle on and off-site damage due to erosion, adequate land and watershed management is necessary [6]. This requires information on the spatial and temporal variability of soil erosion and sediment yield, in order to tailor soil conservation measures and downstream sediment management
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
