Research press release


Nature Geoscience

Sand available to rebuild Mississippi River delta


Jeffrey NittrouerとEnrica Viparelliは、ミシシッピ川下流の堆積物量を解析し、堆積物の全量(砂と泥の両方)は減少しているが、砂の量はダムの建設以降著しく減少しているわけではないことを見つけた。さらに、数値モデルはミシシッピ川下流の流路の砂の量は次の600年間に20%以下減少することを示唆している。


The lower Mississippi River channel contains a significant reservoir of sand that could help to mitigate land loss at the river mouth, according to a study published online in Nature Geoscience. Upstream dams had previously been thought to be starving the Mississippi river delta of the sediment required to build new land and prevent the drowning of the river delta.

Jeffrey Nittrouer and Enrica Viparelli analysed sediment loads in the lower Mississippi River and found that although the total amount of sediment - both sand and mud - has diminished, the amount of sand has not significantly declined since dam construction. Furthermore, numerical modelling suggests that the amount of sand in the lower Mississippi River channel will decline by less than 20% in the next 600 years.

Assuming that sand is more important than mud for the construction of deltaic land, the study proposes that sand will be readily available in the coming centuries to help prevent the Mississippi River delta from drowning.

doi: 10.1038/ngeo2142


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