The River Floodplains Ecological System in Harpers Ferry National Historical Park occupies sandbars, shores, and floodplains of the Potomac and Shenandoah rivers. Smaller occurrences are also found along Flowing Springs Run, a tributary to the Shenandoah. Plants that persist here can withstand varying amounts of flooding. These might include small plants with short life-cycles in some communities, and long-lived trees in others.

The natural communities in this ecological system differ from one another, in part, by where they are situated on the landscape. Just a few feet in elevation can make the difference between whether the natural community will be flooded each spring, every couple of years, or every 15 years—or whether the land will remain flooded throughout the winter months. You can imagine that river banks that regularly get scoured by floating debris (such as large blocks and sheets of ice transported during winter floods) will have a much different appearance than forests on a higher floodplain terrace that only get inundated by slower-moving floodwaters every 3 to 14 years.