A Multi-Scale Analysis of Gully Erosion at Road Drainage Outlets Using LiDAR Technology
Abstract
Gully erosion is an important source of sediment production on transportation networks when road runoff is discharged onto steep slopes. The emergence of LiDAR technology offers new opportunities to measure gully presence and erosion rates, providing important insights into sediment production dynamics on transportation networks. In this study, we used airborne and terrestrial LiDAR to quantify gully presence and rate of change at multiple temporal and spatial scales. Our study is situated in the mountainous landscape of Vermont in the northeastern USA, where previous studies have identified roads as an important source of sediment delivery to receiving waters. To evaluate multi-year to decadal rates of gully erosion associated with roads, we used repeat collects of airborne LiDAR data, measuring gully presence and change over time. To quantify event to seasonal rates of gully erosion, we used high resolution terrestrial LiDAR surveys at 13 field sites, repeatedly surveyed between September 2019 to May 2021. Our results show that gullies at road drainage outfalls are a common occurrence in our study region with a median gully frequency of one in every 2 kilometers of road. Gully presence was influenced by road length, elevation, and slope steepness, revealed by different scales of analysis. Estimates of gully change at annual and longer timescales ranged -24 m3/year to 269 m3/year with 76% of features examined eroding less than 10m3/year. Event to seasonal rates of gully change within this range, with change volume positively associated with rainfall totals over the monitoring period. Collectively, the gullies we studied are dynamically evolving, with some evidence that gully stabilization has occurred in some sites over time. This study can be used as a building block for making roads more resilient to extreme weather events and reducing the environmental impact of roads.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMEP55C0841W