Combining spectroscopy and magnetism with geochemical tracers to improve the discrimination of sediment sources in a homogeneous subtropical catchment

Abstract

Combining spectroscopy and magnetism with geochemical tracers to improve the discrimination of sediment sources in a homogeneous subtropical catchment Rafael Ramon (a,b) ; Olivier Evrard (b) ; J. Patrick Laceby (c) ; Laurent Caner (d) , Alberto V.Inda (e) , Cláudia A.P. de Barros (e) ; Jean P.G. Minella (f) and Tales Tiecher (e)

Combining sediment source tracing techniques with traditional monitoring: The “Arvorezinha catchment” experience

“…After 2014, some studies were also developed at an intermediate scale (catchment areas ranging from 10 1 to 10 2 km 2 ) (Batista et al, 2019; Dambroz et al, 2022; Miguel et al, 2014). In addition, between 2014 and 2020, sediment fingerprinting studies were carried out in catchments with a total area of between 800 and 1200 km 2 (Batista et al, 2019; Franz et al, 2014; Ramon et al, 2020; Tiecher et al, 2018). Nevertheless, research has only been carried out in catchments larger than 2000 km 2 since 2017 (Amorim et al, 2021; le Gall et al, 2017; Tiecher, Minella, Caner, Evrard, et al, 2017).…”

“…Subsequently, some of these techniques, which were initially tested and validated in the Arvorezinha catchment, were also applied in other river catchments in southern Brazil, for example, Ramon et al (2020), Valente et al (2020) and Dambroz et al (2022). The first two studies (Ramon et al, 2020; Valente et al, 2020) provided original approaches; they compared the results of spectroscopic tracers with those obtained with conventional methods (e.g., elemental concentrations, radionuclides). Valente et al (2020) used colour properties and visible ultraviolet spectroscopy in two small‐paired catchments (one with commercial eucalyptus plantations [0.83 km 2 ] and the other with grassland used for livestock farming [1.10 km 2 ]) in the Brazilian Pampa biome.…”

“…Nevertheless, research has only been carried out in catchments larger than 2000 km 2 since 2017 (Amorim et al, 2021; le Gall et al, 2017; Tiecher, Minella, Caner, Evrard, et al, 2017). More recently, the target catchment area jumped to 5942 km 2 in a catchment experiencing a widespread land‐use change in the last years (Ramon et al, 2020), where the conversion of natural grasslands into cropland accelerated soil erosion and sediment delivery to the river systems. In addition, two more tentative approaches have used the sediment collected in the tributary outlet as potential sources to estimate the contribution of sediment from these tributary catchments to that supplied to a larger drainage system, such as the Uruguay River (266 132 km 2 ) (Ramon, 2021) and the Guaíba Lake (85 139 km 2 ) (Tiecher et al, 2022).…”

Tributary contributions to sediment deposited in the Jacuí Delta, Southern Brazil

“…Statistical and computer modelling techniques, such as the sediment fingerprinting approach, provide a powerful suite of methods for quantifying the contribution of each potential source delivering sediment into water courses (Collins et al, 2020). This technique has been increasingly used in Brazil during the last decade, mainly in the southernmost region of the country (Minella et al, 2014;Ramon et al, 2020;Rodrigues et al, 2018;Tiecher et al, 2016;Valente et al, 2020). However, this method is now attracting interest in other parts of the country (Batista et al, 2018;Bispo et al, 2020;Franz et al, 2014;Lima et al, 2020).…”

The potential for colour to provide a robust alternative to high-cost sediment source fingerprinting: Assessment using eight catchments in England

“…Fast to measure tracers based on visible or infra-red spectra are being increasingly used and have the potential to significantly reduce the costs associated with conventional tracer analyses (Martinez-Carreras et al, 2010;Barthod et al, 2015;Brosinsky et al, 2014;Evrard et al, 2019;Ramon et al, 2020;Amorim et al, 2021). Their measurement, however, often still requires specialist laboratory equipment.…”