Is digital shoreline analysis system fit for gully erosion assessment?

Gully erosion represents one of the most destructive geomorphological processes at a global level. Modern methods of gully erosion measurement are typically derived from earlier techniques that have since become outdated. The increasing capabilities of technology had led to new ways of quantifying soil erosion processes (e.g. gully erosion) which must be used in erosion assessment. A tool designed to assess coastal erosion - Digital Shoreline Analysis System (DSAS), is applied to the analysis of gully erosion. To assess the usefulness of this technique, three different types of gullies were chosen (dendritic, linear, and linear that became dendritic) from the Moldavian Plateau of Romania were chosen. Different parameters (SCE, EPR, NSM, and LRR) were tested and analysed. The best results were obtained in the case of dendritic gullies with specific adjustments to the processing values (smoothing distance set to >1000 and transect spacing at values >5 m). In the case of linear gullies, the smoothing distance needs to be set to lower values compared to dendritic gullies (<= 1000). When it comes to the linear gully that evolved into a dendritic gully, the recommendation is to use smoothing distances with high values (>1000) and transect spacing values >10 m. The average erosion rates obtained with the help of DSAS are very close to the ones from the literature of gully erosion on the Moldavian Plateau in Romania (over - 1.5 m/yr and under - 1 m/yr for gullies cut in sandy and clay deposits, respectively). This leads us to the conclusion that the DSAS tool is fit for gully erosion assessment. However, like any other software, it has limitations and possible disadvantages. The tool can be successfully used and applied in the field of soil erosion mitigation, disaster risk reduction, environmental and cultural heritage protection and in reaching the UNSDG.

Automated summary

The study analyzed gully erosion in the Moldavian Plateau using the DSAS tool, finding that specific adjustments are needed for dendritic gullies, lower smoothing distance for linear gullies, and higher values for smoothing distance and transect spacing for linear gullies evolved into dendritic ones. The average erosion rates obtained align closely with existing literature, indicating the suitability of using DSAS for gully erosion assessment in the field.