Multiscalar Assessment of Mining in River Floodplains of the Southeastern United States

Abstract

The mining of sediment is a profitable activity involving clearing and digging out large tracts of land and transformation of the topography. Often, these mines, as well as the pits, ponds, and piles of sediment are near or within the floodplains of a fluvial system. During flood events, the river can overtop and erode riparian areas that separate it from the mine, flowing into the pit and causing planform changes including avulsions. The United States Geological Survey (USGS) has mapped mining sites across the United States, but there are still multiple omissions. Google Earth Pro was used to collect geospatial point data on mines that are within the floodplain boundaries of rivers and creeks in the southeast, a region of high biodiversity. Google Earth extracted data were compared to USGS data using ArcGIS Pro, and their proximity to floodplains and channels was analyzed. Distances between the channels and pits prior to avulsion were referenced from literature (Mossa & Marks, 2011) and used to assess potential risk for other sites. It was found that out of the 1,856 total pits from USGS and Google Earth data, 25.9% were omitted from the USGS data set. This supported the conclusion that current data sets, while thorough, are still incomplete and that a better understanding of site location can reduce the risk of avulsions, which can impact infrastructure, property boundaries, flood risk, and ecological health.