The sea level rise blamed in devastating avulsion in the river deltas

Scientists have found that further sea level rise will increasingly occur avolve — shifts of river channels, often accompanied by devastating floods. According to a study published in the Proceedings of the National Academy of Sciences, with further increase in the level of the ecosystem in the lower reaches of the rivers will be at high risk of failure due to avulse, but the pace of this process can be reduced by engineering the deepening of rivers and extend their processes in deltas.

Many large cities and productive ecosystems, which depend on the global carbon cycle and economic prosperity of entire countries, located in river deltas. It is already known that the sea level rise brings to such landscapes is a great danger, and the geomorphologist was expressed that the rate of formation of sediments from river sediments in the lower reaches of the precipitation does not have time for all incoming water. However, there were suggestions that the sea level rise may indirectly contribute to the destruction of deltas, causing the development avulse.

Avulse, or wandering the Delta — shift of the river channel, which occurs naturally in some deltas with a frequency of approximately once per 10-1000 years. The available observations are contradictory: avulse in the Delta of Rhine and Meuse have increased since the beginning of the Holocene, and in the Delta of the Mitchell river, on the contrary, began to occur less frequently. Avolve in the past was the cause of the devastating floods, and if they will occur more frequently, this can be a real disaster for the ecosystem and the millions of people whose lives depend on the integrity of deltaic landscapes.

Scientists led by Austin Chadwick (Chadwick J. Austin) from the California research Institute investigated the impact of sea-level rise on deltas of several rivers prone avulsion: Parana, Danube, Nile, Mississippi, Assiniboine, the Rhine and the Maas, Magdalena, Orinoco, Amazon, rhône, Huang he, Brahmaputra, Goose, Mitchell and Trinity. For this purpose they used data of instrumental observations and the method of quasi-two-dimensional modeling.

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