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The Magdalena River,a major fluvial system draining most of the Colombian Andes,is a world-class river,in the top 10 in terms of sediment load (≈150 MT/yr).In thisstudy,we explore the major natural factors and anthropogenic influences behind thepatterns in sediment yield on the Magdalena basin and reconstruct the spatial andtemporal pattern of deforestation and agricultural intensification across the basin totest the relationships between land use change and trends in sediment yield.Ourresults show that sediment yield for the whole Magdalena catchment can beexplained by natural variables,including runoff and maximum water discharge.These two estimators explain 58% of variance in sediment yield.Temporal analysesof sediment discharges and land use show that the extent of erosion within thecatchment has increased over the last 10 to 20 years.Many anthropogenicinfluences,including a forest decrease by 40% in a 20-year period,an agricultureand pasture increase by 65%,poor soil conservation and mining practices,andincreasing rates of urbanization,may have accounted for the overall increasingtrends in sediment yield on a regional scale.
The Magdalena River, a major fluvial system draining most of the Colombian Andes, is a world-class river, in the top 10 in terms of sediment load (≈150 MT / yr). In this study, we explore the major natural factors and anthropogenic influences behind the patterns in sediment yield on the Magdalena basin and reconstruct the spatial and temporal pattern of deforestation and agricultural intensification across the basin totest the relationships between land use change and trends in sediment yield. Ourresults show that sediment yield for the whole Magdalena catchment can be expanded by natural variables, including runoff and maximum water discharge. these two estimators explain 58% of variance in sediment yield. Temporal analyzes of sediment discharges and land use show that the extent of erosion within the catchment has increased over the last 10 to 20 years. Many anthropogenic flu, including a forest decrease by 40% in a 20-year period, an agriculture and pasture increase by 65%, poor soil conservatio n and mining practices, andincreasing rates of urbanization, may have accounting for the overall increasingtrends in sediment yield on a regional scale.