Evaluating functional connectivity in a small agricultural catchment under contrasting flood events by using UAV

Abstract

Concentrated erosion, a major feature of land degradation, represents a serious problem for soil and water resources management and a threat to ecosystems. Understanding the internal mechanisms (de‐)coupling sediment pathways can improve the management and resilience of catchments. In this study, concentrated erosion and deposition forms were mapped accurately through field and aerial unmanned aerial vehicle (UAV) campaigns, in order to assess the evolution of connectivity pathways over a series of three contrasted and consecutive flood events occurring between October 2016 and January 2017 (return period ranging from 0.5 to 25 years) in a small Mediterranean agricultural catchment (Can Revull, Mallorca, Spain; 1.4 km2). In addition, a morphometric index of connectivity (IC) was used to identify the potential trajectories of different concentrated erosion forms and deposition areas. IC predictions were calibrated by identifying the optimal critical thresholds, i.e. those most consistent with field observations after each of the events studied. The results found that the index performed well in predicting the occurrence and the length/area of the different type of landforms, giving kappa (κ) coefficients of variation ranging between 0.21 and 0.92 and linear correlations R2 between 0.33 and 0.72. The type of landform affected the correspondence of IC predictions and field observations, with lower thresholds the greater the magnitude of their associated geomorphic processes. Rainfall magnitude proved to be a very important factor controlling the development of erosion and deposition landforms, with large differences in length/area between the contrasted events. The evolution of the observed trajectories revealed feedback dynamics between the structural and functional connectivity of the catchment, in which morphological changes determined the spatial distribution of the processes’ activity in the successive events and vice versa. © 2020 John Wiley & Sons, Ltd.

A new 3D geological modeling method based on remote sensing and its application in Ya'an Area sichuan Province

“…[8] With the development of these traditional remote sensing technologies, UAV has been widely used in environmental research in recent years. [10][11][12][13] However, satellite remote sensing is still used for regular monitoring of large areas. [14,15] The main advantages of satellite imagery are free access to data and different spatial and temporal resolutions.…”

Influence of Different Satellite Imagery on the Analysis of Riparian Leaf Density in a Mountain Stream

“…Satellites and aircrafts equipped with optical, radar, or laser sensors (i.e., satellite platforms) are the most common means for collecting data on and studying Earth's surface [4]. Along with these traditional remote sensing technologies, drones have recently been used to conduct environmental studies [5][6][7][8]. Satellite remote sensing, however, is still used to monitor large areas at regular intervals of time [9,10].…”

Aqua temporaria incognita

“…While field mapping provides the most detailed spatial data (Doering, Uehlinger, Rotach, Schlaepfer, & Tockner, 2007;Godsey & Kirchner, 2014;Jensen et al, 2017;Malard, Uehlinger, Zah, & Tockner, 2006;Sefton, Parry, England, & Angell, 2019;Wigington et al, 2005), it is difficult to do in headwater catchments during rainfall events because conditions can change quickly. Some studies have used drones with cameras for the mapping (Borg Galea, Sadler, Hannah, Datry, & Dugdale, 2019;Calsamiglia et al, 2020;Spence & Mengistu, 2016) but this is difficult for very small headwater streams where vegetation is dense, or during intense rainfall events. Other studies have used low-cost electrical resistance (Bhamjee & Lindsay, 2011;Blasch, Ferré, Christensen, & Hoffmann, 2002;Chapin, Todd, & Zeigler, 2014;Goulsbra, Lindsay, & Evans, 2009;Paillex, Siebers, Ebi, Mesman, & Robinson, 2020;Sherrod, Sauck, & Werkema, 2012) or temperature (Constantz, 2008;Ronan, Prudic, Thodal, & Constantz, 1998) inhabitants have been used determine the medium-term state of temporary streams in populated areas (Gallart, Cid, et al, 2017).…”