The recent issue of the journal Nature Geoscience includes a study regarding the world’s deltas. The study was led by a University of Colorado at Boulder professor James Syvitski. The study revolved around the human activities that are putting deltas at risk.
Approximately 500 million people around the world live on what are considered river deltas. These deltas are naturally low-lying, however many factors are putting these deltas at risk of sinking and flooding.
The study found that 24 of 33 major deltas around the world are sinking. In addition, 85 percent of deltas have seen an increase in severe flooding. 100,000 square miles have subsequently been under water for temporary periods of time. These situations have put millions of people at risk.
New Orleans is considered a classic example of issues that can arise from living on a delta. New Orleans actually sits on a delta which is sinking. The sinking of the delta makes the delta more susceptible to storm surges and flooding.
The sinking of the deltas is considered due to human activity. The main issue causing the sinking of the deltas is trapped sediments which are caused by dams and reservoirs. In addition, groundwater and natural gas extraction is compacting floodplain sediment.
The combination of sinking deltas with potential sea level rises may increase delta flooding by 50 percent. Increased or continued use of dams and reservoirs is predicted to increase these percentages according to the study.
The study published in the journal is just part of a National Science Foundation plan to study various aspects of erosion and flooding around the globe. The array of studies are being funded by $4.2 million by the National Science Foundation and includes hundreds of scientists from around the country.