Edgardo Manuel Latrubesse

The vast majority of large Eurasian rivers are regulated by hydropower dams, but some have survived as free‐flowing rivers so far in the Arctic and along stretches of the Myanmar coast. There, the Ayeyarwady (Irrawaddy) and Salween Rivers, two of the largest rivers of Southeast Asia, provide a huge amount of sediment, nurturing floodplains and deltas and play a unique role in national food security and other socioeconomic and environmental services. Over the past 40 years, Southeast Asia has experienced intense land‐use changes, including deforestation and mining, alongside the rapid expansion of hydropower infrastructure. The region studied here is marked by conflict and political instability, which partly explains why these rivers remain largely free of such infrastructure. Using a method initially applied in the Amazon basin, we assess the environmental condition of four rivers—Ayeyarwady (Irrawaddy), Sittaung, Bilin and Salween—through the lens of hydropower dam development. We highlight the status and preservation of these basins while showing how planned projects could affect their hydrosystems. The Sittaung basin, already saturated by dams, would change little, with nearly 50% of its river network already disconnected. By contrast, the Ayeyarwady basin, still relatively well preserved with about 75% of the basin's whole river lengths free‐flowing, could lose roughly half of that connectivity. The Salween would be the most affected: although about 75% of its river length is currently free‐flowing, this proportion could fall to 8%. Most electricity generated by these projects would be exported to neighbouring countries, contributing less to Myanmar's development and even less to the communities directly affected.

Geomorphological mapping consists of a set of techniques used to map landforms and the processes acting on the Earth's surface. It is a combination of techniques used in the representation of landforms and a useful tool to support information for integrated environmental analyses, territorial management, and geo-environmental risk assessment. Despite its importance and widespread use in several countries, including Brazil, most African countries do not conduct this type of mapping in their territories. This article aims to present the geomorphological mapping of the municipality of Tete in Mozambique. The methodology employed included the use of a Digital Elevation Model (DEM), high-resolution optical images, and fieldwork. The definition and classification of landforms followed the system proposed by Latrubesse and Carvalho (2006), which is nationally recognized and adaptable to different environments. The results indicate that the municipality's area is dominated by denudational units (~208 km²), which have sculpted large Receding Erosion Zones and Planation Surfaces, exhibiting different evolutionary stages. The aggradational units (~85 km²), in turn, are associated with the current and past dynamics of the Zambezi and Revúboè river systems. This study represents a pioneering product in the region and aims to provide support information for urban planning, environmental management, and hydrogeomorphological risk mitigation actions in the municipality of Tete.

Inland tropical dune systems in South America serve as critical archives of past environmental conditions. This study examines the Middle São Francisco Dune Field (MSF-DF), one of the largest inland aeolian systems in tropical South America. We integrate remote sensing, field data, ground-penetrating radar (GPR), gravimetry, and optically stimulated luminescence (OSL) dating to reconstruct the morpho-chronostratigraphy and develop an evolutionary geomorphic–paleoenvironmental model. Our results indicate that dune initiation was triggered by localized deflation of fluvial sediments along a structurally controlled, sediment-rich knickzone of the São Francisco River. These initial deflation nuclei evolved into transgressive dune forms and later stabilized into large-scale source-bordering dunes (SBDs), laying the groundwork for inland aeolian expansion. Geomorphic mapping reveals a pathway-like spatial organization, shaped by prevailing winds, paleotopography, and fluvio-aeolian interactions. The sand field encompasses diverse morphologies, including parabolic megadunes, sandy ramps, and extensive sand sheets. OSL dating across representative landforms identifies four phases of dune activity since ~108 ka. The most significant construction and diversification phase occurred between 61-40 ka, likely driven by increased aridity and wind energy, establishing the dominant dune forms and their spatial configuration. Later reworking episodes during the Late Pleistocene and Holocene were more localized and morphodynamically subdued. By integrating surface morphology, internal stratigraphy, and geochronological data, we propose a process-based conceptual model for the evolution of the MSF-DF. These findings underscore the diagnostic potential of geomorphological analysis in interpreting aeolian systems and highlight the value of morpho-evolutionary-based approaches for reconstructing paleoenvironmental aeolian records in tropical South America

River training structures reorganize flow and sediment pathways in large rivers, yet their effects are commonly inferred from surface morphology and hydraulic assessments, with limited considerations of subsurface architectures. The internal structures, in spite of providing critical records of hydro-geomorphological adjustments, remain little studied due to scarce subsurface data. Here, we investigate Tianxingzhou Island (middle Yangtze River) to evaluate how integrated surface and subsurface observations improve the characterization of engineered sedimentary deposits. Surface morphology and internal architectures are analyzed using UAV-based LiDAR, multi-frequency ground-penetrating radar (GPR), multi-temporal optical imagery, and hydrological records. Multi-temporal imagery is used to control hydrological conditions and depositional evolution, while LiDAR captures fine-scale geomorphic variability and GPR delineates antecedent substrate and post-construction architectures. Low-frequency GPR images pre-engineering conditions and early stratigraphy, whereas high-frequency data resolve internal facies and depositional structures undetected by surface observations. Results reveal pronounced lateral and vertical heterogeneity within relatively thin deposits, reflecting rapid adjustments to variable flow regimes and seasonal forcing. Hydrologically calibrated observations indicate that engineered fields experience frequent submergence, imposing persistent hydraulic forcing that governs sediment redistribution and internal organization. Subsurface architecture resolved by GPR records these stage-dependent processes, directly linking stratigraphic variability to hydrological forcing. The system evolves through three hydro-geomorphic phases: a pre-engineering stage dominated by cross-bar dynamics, a transitional adjustment phase following construction, and a recent stage of relative morphological stability under recurrent inundation. These findings demonstrate that integrating surface–subsurface dataset improves the characterization of flow and sediment interactions in engineered large rivers, and provides a transferable basis for monitoring, predictive modelling, and adaptive river management under variable hydrological regimes.

Reservoir sedimentation remains a critical challenge for the long-term performance of large hydropower systems in tropical regions. This study investigates sedimentation patterns and storage capacity loss in the Itumbiara Reservoir, central Brazil, using an integrated hydrogeophysical and sedimentological approach. High-resolution multibeam bathymetry and sub-bottom profiler data were combined with granulometric analyses of 34 sediment samples to map the pre- and post-impoundment stratigraphy, quantify sediment thickness, and estimate sedimentation rates along the main tributary axes. Results show that post-dam deposits form a discontinuous fine-grained layer, with thickness generally ranging from 0 to 1.33 m and concentrating in deeper zones near the dam and along the former fluvial thalwegs. The Corumbá River arm exhibits the greatest sediment accumulation and the highest normalized silting rate, whereas upstream segments of the Paranaíba and Araguari rivers display substantially lower infilling. Despite localized hotspots of deposition, the reservoir has lost less than 2% of its original storage capacity over 44 years of operation, indicating low sediment yields from cratonic source areas and high trap efficiency with slow morphological adjustment. The integrated dataset reveals that resuspension during water level drawdown and subsequent redeposition in deep, low-energy areas play a key role in redistributing fine sediment within the basin. These findings demonstrate the value of combining acoustic imaging and grain-size data to support sediment management and lifetime assessments of large tropical reservoirs.

Quantitative analysis of alluvial channel patterns is essential in fluvial science, as their morphology both reflects and influences river behavior through interactions with water and sediment regimes, landscape processes, and human interventions. However, a comprehensive global study to identify predominant channel patterns and their underlying mechanisms remains lacking. Here, we map global alluvial channel patterns using high-resolution satellite observations. Our results reveal a hidden dominance of anabranching channels that surprisingly constitute half (51%) of total reach length globally, exceeding meandering (24%), straight (18%), and braided (7%) channels. In non-mountainous settings, anabranching channels dominate most continents except Oceania. They are not confined to typical alluvial lowland systems, also comprising 50% of alluvial tracts in mountains. While anabranching is typically associated with gentle slopes and expansive floodplains, these conditions are not exclusive determinants. The prevalence of anabranching channels transforms fundamental perspectives on global river systems, posing challenges for the fluvial geomorphology community.

Alluvial sediments bordering rivers of the southern Peruvian Amazon are enriched with gold, which has sustained an artisanal gold mining economy within a biodiversity hotspot for the past several decades. While it is clear that sweeping deforestation by miners has resulted in substantial loss of above-ground carbon stocks and increased greenhouse emissions, the region also harbors a sizable below-ground carbon stock in the form of peatlands, and how these have fared against decades of mining expansion is uncertain. Here, we use Landsat’s continuous archival record spanning over 35 years to monitor the expansion of gold mining in a major Amazonian peat complex along the alluvial plain of the Madre de Dios River. We detect over 550 ha of peatland surface area that has been lost to gold mining, potentially accounting for between 0.2 and 0.7 Tg of emitted below-ground carbon. Alarmingly, the majority of this loss (55%) has occurred within the past two years. Mining inside peatlands currently accounts for 9% of total mining, but projections suggest a 25% share by 2027 as mining within peatland is accelerating considerably faster than mining in the alluvial plain as a whole. The startling surge of peatland degradation is synchronous with the arrival of an aggressive mining front into the most distal reaches of the alluvial plain where peatlands are most abundant. Already, 63 of 219 peatlands in the alluvial plain show evidence of mining within their borders, putting over 10 000 ha of peatland area and between 3.5 and 14.5 TgC at imminent risk. The rapid proliferation of gold mining inside peatlands appears to be of such scope as to be an existential threat to the entire peatland complex.

Loess, loess-like, sandy loess, and sandy-silty fluvial–aeolian deposits are intercalated to fluvial sediments and lie on a flat surface under intense agricultural land use in Bardibas, Mahottari district, central Nepal. To identify the depositional processes and provenance, we carried out geochemical, mineralogical, SEM, and grain-size analyses. Optically stimulated luminescence (OSL) dating shows the aeolian deposits are from the late Holocene (1.0–4.8 ka). Our results demonstrate that the loess and loess-like deposits (i) were dominantly sourced locally from deflation Quaternary sediments of the Terai Plain; (ii) are related to the composition of Siwalik rocks; and (iii) were deposited during dry periods of weak activity of the Indian Summer Monsoon.