Nick Fetty | August 28, 2014

Geologists at Indiana University have found that “goldilocks plant growth” – or not too little, not too much vegetation – is most effective at keeping river deltas resilient.

This vegetation can help “slow the flow of water and cause more sediment to be deposited” which helps to prevent rising sea levels from saturating sensitive marshlands. However, when the vegetation is either too tall or too dense it can prevent sentiment from being deposited in the marsh.

In addition to rising sea levels, population growth, pollution, development and erosion have also had detrimental effects on river deltas. Approximately 10 percent of the world’s population live in river delta regions.

William Nardin (a postdoctoral fellow in the Department of Geological Sciences at IU-Bloomington) and Douglas A. Edmonds (holds the Robert R. Shrock Professorship in Sedimentary Geology and is an assistant professor of geological sciences at IU) authored the report and used computer modeling to simulate 75 scenarios involving different vegetation densities and river flow rates. Edmonds authored a similar report in 2012.

While the researchers concluded that the ideal level of vegetation helps to retain the greatest amount of sentiment, the vegetation had little effect on sentiment levels when faced with unpredictable conditions such as storms and flooding.

The full report was published in the journal Nature Geoscience earlier this month.