Erosion and sediment yield in a changing environment

Abstract

Existing assessments of patterns of global sediment flux from the land to the oceans and of global patterns of sediment yield have tended to treat the global denudational system as a static system. There is, however, increasing evidence that the sediment loads of the world's rivers have changed significantly as a result of human activity and interference. As well as being of scientific interest, such changes have important environmental and economic implications and should be included in current concerns for the impact of global change on the Earth's environment. Lack of reliable long-term records precludes a detailed assessment of longer-term and recent changes in suspended sediment transport by world rivers, but the available information can be supplemented by evidence from several other sources, which include the long-term geological perspective, lake sediment records, catchment experiments and space-time substitution; all of which provide valuable information concerning the sensitivity of river sediment loads to environmental change and the magnitude of the changes involved. There is evidence of significant increases and decreases in sediment yields in many areas of the world. Any attempt to relate such changes in sediment loads to environmental change within the upstream drainage basin must, however, take account of the complexity of the sediment delivery system.

Widening the scope: linking coastal sedimentation with watershed dynamics in Java, Indonesia

“…Galunggung in the upper catchment erupted in 1822, 1894, 1918-83, and 1984(GVP 2014. Rivers affected by volcanic eruptions exhibit the highest sediment yields (Milliman and Syvitski 1992;Walling and Webb 1996). The kinds, magnitudes, and temporal courses of volcanic eruptions' hydrological effects have been documented elsewhere (Kuenzi et al 1979;Major et al 2000;Hayes et al 2002;Lavigne 2004).…”

Erosion thresholds and suspended sediment yields, Waipaoa River Basin, New Zealand

“…The Waiapu River basin also has a higher mean annual rainfall, but its headwaters are underlain by poorly consolidated marine sediments, and most of the native forest cover has been cleared and replaced by pasture. This combination of environmental factors gives rise to a specific sediment yield that is 3 times larger than that of the Waipaoa River and ranks among the highest recorded anywhere in the world [Walling and Webb, 1996]. Thus despite their apparent regional affinity, there is a wide variation in the sediment yields of these three basins.…”

Evaluation of hydrology, suspended sediment and Nickel loads in a small watershed in Basque Country (Northern Spain) using eco-hydrological SWAT model

“…At the level of Spain, the annual sediment exportation is lower than reported by Walling and Webb (1996) for Mediterranean basins of the Iberian Peninsula (100-250 t km x2 y x1 ). As for the Basque Country main basins, there are clear differences between each other, depending on its size and topography.…”