Dune grasses

Figure 17. Grasses like these can stabilize a dune and protect it from erosion. (Photograph by the author. More about the photograph)

There are things people can do to retain or increase sand volume on barrier islands. One of these is to plant dune grasses like those in Figure 17. Not only do such plantings stabilize the sand that already exists by reducing the ability of wind to move it elsewhere, but over time the plants will cause more sand to be deposited than would otherwise be the case.

If you look at the individual grains of sand in a dune, you will find them to be of uniform small size. These are the grains that are most easily moved. Moderate breezes are sufficient to move find sand but not particles of either larger or smaller size. Once moving in light winds, only a modest decrease of disruption of the windfield eliminates sand transport.

So, although the modest sprigging of dune grasses shown in Figure 17 may look like weak straws in the ocean wind, they will be effective in stabilizing this sandy area. They will grow upward, trapping sand, until a hummocky mound of sand like those seen in Figure 12 is formed. This is how nature builds sand dunes, and perhaps it is also a good way for humans to do so.

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