Using Drones for Erosion and Sediment Control Inspections

While the use of unmanned aerial systems (UAS or drones) for sediment and erosion control inspections is not new, Wake County government took a scientific approach to studying the efficiency of using drones to inspect construction sites. We compared the amount of time spent inspecting a site via drone usage versus walking, as well as the percentage of non-compliant items observed during each approach. The presentation will discuss the results of this study, along with other aspects of drone inspections, including: equipment, licensing, legal aspects, typical items missed, and other non-quantifiable benefits. This information will be beneficial for sediment and erosion control inspectors, grading contractors, private consultants, and regulators, and will provide almost everything you need to know to start your own drone inspection program.

Full Abstract: The Water Quality division of Wake County government studied how efficient and effective drones can be for sediment and erosion control inspections. This study examined the amount of time saved by conducting inspections of permitted construction sites using an unmanned aerial system compared to the traditional way of walking a site. The effectiveness of drones at identifying non-compliant items at construction sites was also identified. Simultaneous drone and manual inspections were conducted at five sites on three different occasions. The construction sites varied in size from 23.3 to 156 disturbed acres. They were all located in Wake County, NC, which is considered part of the piedmont region of North Carolina. The total inspection time was recorded, along with the amount of non-compliant items observed at each location. The drone inspections had a median time saved of 62.5%. The drone inspections also identified a median of 83.3% of the total non-compliant items. A slight decrease of effectiveness of around 17% was observed from winter to summer due to tree canopy. Construction sites with larger disturbed areas will see a greater benefit of drone use than smaller sites. Local governments, as well as grading contractors, can use drones as an efficient tool in their belt to increase their awareness of site conditions. Drones can provide a quick assessment of a site with relatively accurate results. It is recommended that drone inspections be alternated with manual inspections, since drones will not always observe all non-compliant items. With local and state governments having limited budgets for full time sediment and erosion control inspectors, this study demonstrates the effectiveness and efficiency of utilizing drones for such inspections, which offers a potential for improved water quality due to a decrease in inspection time.