UAV and LiDAR Data in the Service of Bank Gully Erosion Measurement in Rambla de Algeciras Lakeshore

Abstract

The Rambla de Algeciras lake in Murcia is a reservoir for drinking water and contributes to the reduction of flooding. With a semi-arid climate and a very friable nature of the geological formations at the lakeshore level, the emergence and development of bank gullies is favored and poses a problem of silting of the dam. A study was conducted on these lakeshores to estimate the sediment input from the bank gullies. In 2018, three gullies of different types were the subject of three UAV photography missions to model in high resolution their low topographic change, using the SfM-MVS photogrammetry method. The combination of two configurations of nadir and oblique photography allowed us to obtain a complete high-resolution modeling of complex bank gullies with overhangs, as it was the case in site 3. To study annual lakeshore variability and sediment dynamics we used LiDAR data from the PNOA project taken in 2009 and 2016. For a better error analysis of UAV photogrammetry data we compared spatially variable and uniform uncertainty models, while taking into account the different sources of error. For LiDAR data, on the other hand, we used a spatially uniform error model. Depending on the geomorphology of the gullies and the configuration of the data capture, we chose the most appropriate method to detect geomorphological changes on the surfaces of the bank gullies. At site 3 the gully topography is complex, so we performed a 3D distance calculation between point clouds using the M3C2 algorithm to estimate the sediment budget. On sites 1 and 2 we used the DoD technique to estimate the sediment budget as it was the case for the LiDAR data. The results of the LiDAR and UAV data reveal significant lakeshore erosion activity by bank gullies since the annual inflow from the banks is estimated at 39 T/ha/year.

New Method for Automated Quantification of Vertical Spatio-Temporal Changes within Gully Cross-Sections Based on Very-High-Resolution Models

“…The use of Structurefrom-Motion (SfM) algorithms and unmanned aerial vehicles (UAV) photogrammetry has been recently particularly popular for the creation of VHR DSMs and as such it has wide application in various geomorphological researches . In particular, the application of UAV photogrammetry and SfM algorithms have found wide application in soil erosion related research [51][52][53][54][55][56][57][58][59][60]64]. VHR DSMs provide the perfect basis for a pixel-orientated analysis of morphological changes and quantification of spatio-temporal changes at a sub-decimeter scale [40,65].…”

Evaluation of sediment connectivity through physically-based erosion modeling of landscape factor at the event scale

“…Limestones and dolomites, siliceous marls, and marly limestone outcrops are present in the headwaters, while in the middle and lower parts of the basin marls and alluvial sediments abound, which have favored linear incision, resulting in Vshaped badlands. The associated edaphic profile, of detrital nature composed by little or no cemented loamy soils, marls and polygenic conglomerates, are highly erodible and subject to different dominant erosive processes, such as laminar D R A F T 12 flow, rilling, piping and gullying (Hout et al, 2020). At the studied site, previous studies have estimated potential erosion using the RUSLE model (Dirección General de Medio Natural y Política Forestal, 2007; Fig.…”

Special Issue “Multiscale Impacts of Anthropogenic and Climate Changes on Tropical and Mediterranean Hydrology”

“…The papers showcase studies under equatorial, tropical humid, semi-arid, and Mediterranean climate. All spatial scales are investigated, from the very local scale of gullies in Spain [14] to the largest rivers of the world, the Amazon and Orinoco rivers in South America [13] and Congo River in Central Africa [15]. The whole African continent is also the topic of the paper of Dieulin et al [16] (2020), presenting a new continental monthly rainfall dataset at the half-degree square scale covering the years 1940 to 1999, computed only from observations from ground-based stations.…”

“…Higher Nash-Sutcliffe Efficiency (NSE) values for both MDAR and ISW are mostly obtained with the three most physically similar donor stations in the Middle Euphrates basin and with the two most physically similar donor stations in the Upper Euphrates basin. Hout et al [14] use lidar data to survey the evolution of the morphology of gullies on the slopes of a lake in semi-arid southern Spain. Due to the nature of the geological formations at the lakeshore level, gully erosion is very high and leads to silting up of the dam.…”