Author(s): Josef Krasa; Daniel Zizala; Jakub Stasek; Adam Tejkl

Linked Author(s): Josef Krása

Keywords: Erosion monitoring; Planetscope; Remote sensing; Rills; Gullies

Abstract: The results of the analysis show that data from Planet satellites are partially usable for monitoring the effects of erosion and identifying erosion events. Planet's data, mainly due to their time coverage, make it possible to find suitable images on which the development of the soil surface before and after erosion events can be monitored, or even longer, the influence of erosion events on agricultural crops can be monitored. Unlike other satellite optical data, in most cases it is possible to find a cloudless image from the period shortly after the erosion event. For all erosion events, it was possible to find images on which it was possible to assess the erosion damage. Relatively high-quality images were available for spring or summer events. Images for autumn events sometimes showed poorer image quality due to the lower elevation of the Sun and thus the reduced intensity of sunlight. Moreover, the radiometric difference of individual images remains problematic, which are inconsistent due to different acquisition times and different sensor qualities, making it difficult to use automated image enhancement methods and probably also make it difficult to use methods of automatic or semi-automatic identification of erosion damages in images. In total, 379 Planet satellite scenes were analysed covering 54 significant rainfall runoff events with known erosion fluxes from the verification datasets. Most of the visible damages are showing larger rills and ephemeral gullies directly at the soil surfaces (at 72 scenes), so in the case of pronounced erosion it can be detected. On the other hand, even if the database contained only known and verified erosion effects (visible at aerial or UAV orthophoto), in 191 cases (50%) no effect was detectable using Planetscope. The analysis showed that erosion damage can be identified using Planet data. However, their identification depends mainly on their spatial extent and the size of erosion damage. Depending on the resolution of the satellite data, it is possible to identify especially ephemeral rills or rills of a larger extent. In the case of damages connected with sheet erosion or in the case of the development of a thinner network of smaller erosion rills, the manifestations are no longer visible, either on bare soil or later on crops. Access to Planet data was obtained through the project ID 60639 within the ESA Third Party Missions PLANET program. The research is conducted within the frame of a project No. SS01020366 “Using remote sensing to assess negative impacts of rainstorms“, supported by the Technology Agency of the Czech Republic and within the H2020 project SHUi (773903). The support is highly acknowledged.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221444

Year: 2022