Articles | Volume 12, issue 2
Brief communication
21 Feb 2018
Brief communication |  | 21 Feb 2018

Brief Communication: Mapping river ice using drones and structure from motion

Knut Alfredsen, Christian Haas, Jeffrey A. Tuhtan, and Peggy Zinke

Abstract. In cold climate regions, the formation and break-up of river ice is important for river morphology, winter water supply, and riparian and instream ecology as well as for hydraulic engineering. Data on river ice is therefore significant, both to understand river ice processes directly and to assess ice effects on other systems. Ice measurement is complicated due to difficult site access, the inherent complexity of ice formations, and the potential danger involved in carrying out on-ice measurements. Remote sensing methods are therefore highly useful, and data from satellite-based sensors and, increasingly, aerial and terrestrial imagery are currently applied. Access to low cost drone systems with quality cameras and structure from motion software opens up a new possibility for mapping complex ice formations. Through this method, a georeferenced surface model can be built and data on ice thickness, spatial distribution, and volume can be extracted without accessing the ice, and with considerably fewer measurement efforts compared to traditional surveying methods. A methodology applied to ice mapping is outlined here, and examples are shown of how to successfully derive quantitative data on ice processes.

Short summary
The formation and breakup of ice on rivers in winter may have impacts on everything from built infrastructure to river ecology. Collecting data on river ice is challenging both technically and because since access to the ice may not always be safe. Here we use a low cost drone to map river ice using aerial imagery and a photogrammetry. Through this we can assess ice volumes, ice extent and ice formation and how ice can affect processes in the river and the utilisation of rivers in winter.