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Background: The European flood that occurred between July 13th and 16th 2021, was a natural disaster that caused significant damage in Central European countries, including Germany, Netherlands, Belgium, and Luxembourg. This disaster resulted in the highest number of fatalities from a natural disaster in Germany during the twenty-first century, with over 180 people losing their lives and causing damages exceeding 30 bn€. The flood caused severe destruction in small mountainous river systems such as the Vicht and Inde rivers, particularly in the German state of North Rhine-Westphalia. In addition, the flood caused a significant release of pollutants, including old burdens from the former mining area of Stolberg. Results: To assess the extent of pollution caused by the flood in the affected floodplains and urban areas, this study was conducted to inventorize organic contaminants identified through a non-target screening in water and sediment samples taken immediately after the disastrous flood event. In total, 56 individual contaminants were identified from the water samples, including substances derived from urban effluents, such as personal care products, cosmetics, odors, technical additives, pharmaceuticals and surfactants. The analysis of sediment samples revealed different types of environmentally hazardous contaminants, such as petrogenics, urban effluent and wastewater indicators, chlorinated industrial compounds, and pesticides. This diverse range of pollutants and their broad dispersion across various environments in the catchment is attributed to the dynamic nature of the flood. Conclusion: The inventory of identified organic contaminants raises long-term environmental concerns and potential health implications for the flood-affected Vicht–Inde region. [ABSTRACT FROM AUTHOR]

Background: In July 2021, destructive floods in Western Europe were triggered by enormous precipitation rates related to a low-pressure system named "Bernd." These catastrophic events led not only to major damage to infrastructure, severe economic losses, and the loss of lives but also to significant landscape changes and modifications. Here, we focus, as a case study, on the flood aftermath of the Ahr Valley in Rhineland-Palatinate state in western Germany, as it was one of the most affected and destroyed regions by the flood. We utilize high-resolution Digital Terrain Models (DTMs) based on airborne Light Detection and Ranging (LiDAR) that were taken shortly before and after the flood to investigate insights into geomorphic changes. Results: By calculating Digital Terrain Models of Difference (DoD), we are able to quantify volumetric and areal changes caused by erosional and depositional processes for different sites in the Ahr Valley. Due to the morphology of the narrow Ahr Valley, most of the erosion and deposition is located within the deeply incised canyon of the Ahr River. The comprehensive analysis reveals notable morphological modifications throughout the study area, with a calculated erosion/deposition areal ratio of 0.46 and an erosion/deposition volumetric ratio of 0.63. Our findings indicate massive deposition regarding both areal and volumetric. We selected six different locations along the Ahr Valley that showcase distinct aspects of flood-induced fluvial morpho-dynamics. Deposition occurred mainly in point bars and downstream of destroyed artificial levees, in a braided river style. Conclusion: Our investigations contribute to an overview and assessment of the morphological response to the destructive flood in the Ahr Valley. The results emphasize the necessity for implementing effective flood management strategies, as most of the urban areas in the Ahr Valley were flooded. Moreover, our results provide valuable insights into the impacted areas, highlighting vulnerable locations for flood-related erosion and deposition. This information could contribute to future mitigation and protection efforts, aiding in the development of comprehensive strategies to minimize the impact of similar events in the future. [ABSTRACT FROM AUTHOR]

This study presents results from two sediment cores collected on the southern Portuguese shelf attempting to, partially, fill the knowledge gap of the offshore record of high-energy events. The results were obtained based on description of cores, microtextural analysis of quartz grains, and foraminiferal taphonomy. The lithostratigraphy corresponds to Late Holocene sedimentation, with interesting intercalations of medium sand rich with bioclastic fragments and erosive basal contact. In terms of microtextures, a high degree of mechanical marks on the grains associated with tsunami deposition was observed and reflects the high-energy hydrodynamic processes. In compositional terms, the higher presence of quartz grains in these units favors the increase of mechanical marks because grain-to-grain contact is more intense. Additionally, the geomorphological setting of the coring sites controlled the degree and type of mechanical microtextures observed. Furthermore, post-depositional changes and characteristics of the original sediment source contribute to explain the occurrence of dissolution in units of GeoB23513-02. The foraminiferal taphonomy displayed a predominance of dissolution alteration in the test surfaces that was more evident in the silty layers. On the other hand, similar to quartz grain microtextural signature, the sandy high-energy units exhibit a slight predominance of physical processes despite the still strong presence of dissolution. The sole presence of foraminifera species from the middle to the outer shelf in some units is an indication that there was little reworking of specimens. This work aims to increase the understanding of dynamics during Holocene high-energy events and to characterize their backwash phases through the different imprints left in the sedimentary offshore record of the Portuguese Algarve shelf. [ABSTRACT FROM AUTHOR]

The 2011 Tohoku-oki tsunami left a characteristic geochemical signature in the sediments of the Misawa harbor on the Aomori coastline (northern Japan), not only in vertical stratigraphy but also in lateral distribution. Suitable indicator compounds for the tsunami impact were used to identify and characterize the distribution of geochemical patterns within the harbor area. Specific compounds are illustrating the different emission sources and distribution during the 2011 tsunami. Petrogenic-derived markers, such as hopanes and polycyclic aromatic hydrocarbons, provide information about the tsunami-related destruction of facilities and technical material and the subsequent release of, for instance, oil and grease. Linear alkylbenzenes and diisopropylnaphthalene are used to identify sewage-derived contaminants released by the tsunami. Old burden markers such as dichlorodiphenyltrichloroethane and its metabolites or polychlorinated biphenyl signal erosion and rearrangement of contaminants present in the sediments prior to the tsunami. Distribution of the analyzed pollutant groups indicate the tsunami-related release through various emission sources and their potential origin. While petrogenic-derived pollutants revealed a significant local spread with hotspot formation near the release, sewage-derived compounds were widely distributed and originated from a diffuse source not necessarily located in the harbor area. In contrast to freshly released contaminants, old burden markers are characterized by erosion of contaminated pre-tsunami sediment, the remobilization of pollutants and subsequent deposition of these sediment-bound contaminants in the tsunami layer. The correlation between all pollutant groups by their preferred accumulation reveals that source-specific compounds show different emission sources but reveal also a topographical control of the pollutant distribution by the 2011 tsunami. [ABSTRACT FROM AUTHOR]

Tsunamis pose a substantial threat to coastal communities around the globe. To counter their effects, several hard and soft mitigation measures are applied, the choice of which essentially depends on regional expectations, historical experiences and economic capabilities. These countermeasures encompass hard measures to physically prevent tsunami impacts such as different types of seawalls or offshore breakwaters, as well as soft measures such as long-term tsunami hazard assessment, tsunami education, evacuation plans, early-warning systems or coastal afforestation. Whist hard countermeasures generally aim at reducing the inundation level and distance, soft countermeasures focus mainly on enhanced resilience and decreased vulnerability or nature-based wave impact mitigation. In this paper, the efficacy of hard countermeasures is evaluated through a comprehensive literature review. The recent large-scale tsunami events facilitate the assessment of performance characteristics of countermeasures and related damaging processes by in-situ observations. An overview and comparison of such damages and dependencies are given and new approaches for mitigating tsunami impacts are presented. [ABSTRACT FROM AUTHOR]

Fast growing coastal population centers face an increasing vulnerability to several emission sources of anthropogenic and industrial pollutants. The ongoing industrialization in emerging countries increases the environmental and human risk for people living in coastal megacities, especially in the global south of Asia. Extreme weather events, such as heavy rainfalls and resulting flood events, are projected to increase in frequency in the foreseen future, facing an increasing vulnerability to monsoon-induced floods and the release and distribution of xenobiotics causing harm to communities and the environment along a river's pathway. To endeavor the unknown risks posed by these toxic floods and to assess the associated contamination distribution, the preserved organic geochemical signature from floodplain sediments is studied. This investigation evaluates the inorganic and organic pollutant assemblage in ten surface sediments along the Adyar and Cooum river in the urban areas of Chennai (southern India). Potentially toxic elements (Cr, Ni, Cu, Zn, Pb) show a continuous concentration decrease downstream. Four main groups of persistent organic pollutants have been detected: petrogenic pollutants (hopanes, PAHs), urban wastewater pollutants (LABs, DEHA, methyl-triclosan, octocrylene), technical compounds (Mesamoll®, DPE, NBFA), and pesticides (DDX). While most organic compounds show source specific properties, the definite sources for others remain vague based on the multitude of potential sources and diffusiveness of anthropogenic emissions. The chosen approaches have shown that urban wastewater pollutants and several technical compounds are suitable to assess the anthropogenic-induced contamination in floodplain sediments. However, sedimentary archives in fast-growing, urbanized environments are influenced and superimposed by anthropogenic alterations. [ABSTRACT FROM AUTHOR]

The 2011 Tohoku-oki tsunami released and mobilized many anthropogenic and natural organic compounds and, hereby, left a clear signature in its sedimentary remnants. In this study, a wide variety of organic marker substances were analyzed in 15 sediment profiles from the Aomori coast (Northern Japan). Total organic carbon (TOC) and fine grain fraction normalization have been tested with the wide dataset, and the already more frequently used TOC normalization was proven to be the more suitable one. Concentration profiles and specific ratios have been interpreted using two different approaches. Differentiation of marine and terrestrial matter characterized mixing processes due to the tsunami impact. Linking constituents to anthropogenic emission sources pointed not only to pollution revealed by the tsunami damages but also to dispersion processes, in particular erosion, transport, mixing and redeposition of particle-associated contaminants. Both approaches have been proved to identify unambiguously tsunamites in sedimentary archives and to reveal detailed insights into the tsunami-driven dispersion of particle-associated organic matter. Generally, the organic geochemical proxies as tested in this study can be reliably used to identify and characterize tsunami deposits in the sedimentary record. Finally, this strategy can be transferred to other locations affected by tsunamis for an in-depth characterization of the destruction and environmental changes induced by tsunami events. [ABSTRACT FROM AUTHOR]

With a minimum of three reported waves, the 2011 Tohoku-oki tsunami's destructive force caused massive damage along the northern Japanese Aomori coast. At Misawa the coastal control area was inundated up to 550 m inland and sandy sediment remnants can be traced to c. 350 m (c. 61–63% of the maximum inundation) from the shoreline. Linking the discovery of floatable plastic objects within a woody and organic layer to our analytical data lead to the detection of a yet undocumented woody-organic tsunami deposit first appearing on top of the sandy deposit but then reaching even further inland (approx. 69–72% of the max. inundation). By this observation our understanding of the documented part of the tsunami inundation may be improved. As a consequence, sand sheets of historic and paleo-tsunamis represent minimum estimates for the coastal inundation and underestimation may be reduced by addressing the woody and organic fraction of a tsunami's inundation. [ABSTRACT FROM AUTHOR]

The Karakoram Highway links north Pakistan with southwest China. It passes through unique geomorphological, geological and tectonic setting. This study focused 200-km-long section of the highway starting from Besham until Chilas. Landslides are frequent and are mostly triggered by torrential rain during Monsoon and Westerlies, leading to highway blockade. Rockfall and debris flow are prime mode of slope failures. Regional to site-specific approach was implemented to assess risk associated with these two modes. Remote sensing-based techniques were used to identify potential hazardous sites, which were further investigated for risk assessment. Modified Pierson's rockfall hazard rating system (RHRS) rated potential rockfalls, whereas semi-quantitative technique was employed to assess debris flows. Normalized scores of each site shaped the final map, further classified into four zones: very high, high, intermediate and low risk. [ABSTRACT FROM AUTHOR]

Protecting our water resources in terms of quality and quantity is considered one of the big challenges of the twenty-first century, which requires global and multidisciplinary solutions. A specific threat to water resources, in particular, is the increased occurrence and frequency of flood events due to climate change which has significant environmental and socioeconomic impacts. In addition to climate change, flooding (or subsequent erosion and run-off) may be exacerbated by, or result from, land use activities, obstruction of waterways, or urbanization of floodplains, as well as mining and other anthropogenic activities that alter natural flow regimes. Climate change and other anthropogenic induced flood events threaten the quantity of water as well as the quality of ecosystems and associated aquatic life. The quality of water can be significantly reduced through the unintentional distribution of pollutants, damage of infrastructure, and distribution of sediments and suspended materials during flood events. To understand and predict how flood events and associated distribution of pollutants may impact ecosystem and human health, as well as infrastructure, large-scale interdisciplinary collaborative efforts are required, which involve ecotoxicologists, hydrologists, chemists, geoscientists, water engineers, and socioeconomists. The research network 'project house water' consists of a number of experts from a wide range of disciplines and was established to improve our current understanding of flood events and associated societal and environmental impacts. The concept of project house and similar seed fund and boost fund projects was established by the RWTH Aachen University within the framework of the German excellence initiative with support of the German research foundation (DFG) to promote and fund interdisciplinary research projects and provide a platform for scientists to collaborate on innovative, challenging research. Project house water consists of six proof-of-concept studies in very diverse and interdisciplinary areas of research (ecotoxicology, water, and chemical process engineering, geography, sociology, economy). The goal is to promote and foster high-quality research in the areas of water research and flood-risk assessments that combine and build off-laboratory experiments with modeling, monitoring, and surveys, as well as the use of applied methods and techniques across a variety of disciplines. [ABSTRACT FROM AUTHOR]

We present new stable isotope (δO and δC) and diatom data from a 67-m sediment core (BAN II) from Lake Banyoles, northeastern Spain. We reassessed the chronology of the sequence by correlating stable isotope data with a shorter U-series-dated record from the lake, confirming a sedimentological offset between the two cores and demonstrating that BAN II spans Marine Isotope Stages (MIS) 3-1. Through comparison with previous records, the multi-proxy data are used to improve understanding of palaeolimnological dynamics and, by inference, western Mediterranean climate and environmental change during the past ca. 50,000 years. Three main zones, defined by isotope and diatom data, correspond to the MIS. The basal zone (MIS 3) is characterised by fluctuating δO and benthic diatom abundance, indicating a high degree of environmental and climate variability, concomitant with large lake-level changes. During the full glacial (MIS 2), relatively constant δO and a poorly preserved planktonic-dominated diatom assemblage suggest stability, and intermittently, unusually high lake level. In MIS 1, δO and δC initially transition to lower values, recording a pattern of Late Glacial to Holocene change that is similar to other Mediterranean records. This study suggests that Lake Banyoles responds limnologically to changes in the North Atlantic ocean-atmosphere system and provides an important dataset from the Iberian Peninsula, a region in need of longer-term records that can be used to correlate between marine and terrestrial archives, and between the western and eastern Mediterranean. [ABSTRACT FROM AUTHOR]

Heavy rainfall on February 20, 2010, triggered numerous shallow rapid landslides across Madeira Island, a Portuguese archipelago in the North Atlantic. Two days after the extreme rainfall event, a field campaign was started which involved describing and mapping a variety of landslide types and the related losses at 120 different locations throughout the Island. Most of the failures started as debris slides or avalanches at high elevations and transformed into debris flows which rushed downslope into populated coastal areas. Over half of the mapped landslides were located in the central and southern area of the island. A further 1,257 landslide locations were revealed in these areas using remote sensing data which were then assembled in a spatial database. Due to anthropogenic influences caused by urban development and population expansion, the event demonstrated the increased vulnerability of the island's infrastructure. In order to mitigate future losses, it is important to quantify the typical preparatory factors which contribute to rainfall-induced landslides. This increases our understanding of the hazards and associated risks. The analysis shows that based on their spatial frequency, distribution and in the context of the drainage system, three main factors contribute to the triggering of the landslides due to the heavy rainfall event in February 2010: the characteristic soil type, the land cover and the slope gradient. It can now be recognized that the distribution of landslides is highly dependent on the temporal and spatial distribution of these factors. Furthermore, the anthropogenic impact on the extent of the hazard becomes obvious due to poor settlement planning and drainage system modification. [ABSTRACT FROM AUTHOR]

A 1,460-m-long profile of a Late Glacial subglacial, glacio-fluvial, glacio-limnic and glacio-deltaic sequence exposed at a cliff section on Usedom Island (SW Baltic Sea coast) is described. The sequence is up to 31 m thick and shows sedimentary structures typical of a glacial setting. Soft-sediment deformation is encountered and is associated with changes in lithology. These deformations include liquefaction, slumping, and faulting. As the most plausible cause, earthquake-induced shaking is discussed. The associated neotectonic activity is seen as a consequence of the postglacial isostatic crustal rebound. As the deglaciation earthquake ratio diminishes with time and as the rebound is phasing out, no large earthquakes are anticipated for northern Germany, although in conclusion the lithosphere of the North German Basin has to be regarded as weakened by repeated ice loading and deloading. [ABSTRACT FROM AUTHOR]

High-resolution multi-channel seismic data from continental slopes with minor sediment input off southwest Mallorca Island, the Bay of Oran (Algeria) and the Alboran Ridge reveal evidence that the Messinian erosional surface is terraced at an almost constant depth interval between 320 and 380 m below present-day sea level. It is proposed that these several hundred- to 2,000-m-wide terraces were eroded contemporaneously and essentially at the same depth. Present-day differences in these depths result from subsidence or uplift in the individual realms. The terraces are thought to have evolved during one or multiple periods of sea-level stagnancy in the Western Mediterranean Basin. According to several published scenarios, a single or multiple periods of relative sea-level stillstand occurred during the Messinian desiccation event, generally known as the Messinian Salinity Crisis. Some authors suggest that the stagnancy started during the refilling phase of the Mediterranean basins. When the rising sea level reached the height of the Sicily Sill, the water spilled over this swell into the eastern basin. The stagnancy persisted until sea level in the eastern basin caught up with the western Mediterranean water level. Other authors assigned periods of sea-level stagnancy to drawdown phases, when inflowing waters from the Atlantic kept the western sea level constant at the depth of the Sicily Sill. Our findings corroborate all those Messinian sea-level reconstructions, forwarding that a single or multiple sea-level stagnancies at the depth of the Sicily Sill lasted long enough to significantly erode the upper slope. Our data also have implications for the ongoing debate of the palaeo-depth of the Sicily Sill. Since the Mallorcan plateau experienced the least vertical movement, the observed terrace depth of 380 m there is inferred to be close to the Messinian depth of this swell. [ABSTRACT FROM AUTHOR]

A dense grid of multichannel high-resolution seismic sections from the Bay of Kiel in the western Baltic Sea has been interpreted in order to reveal the Mesozoic and Cenozoic geological evolution of the northern part of the North German Basin. The overall geological evolution of the study area can be separated into four distinct periods. During the Triassic and the Early Jurassic, E–W extension and the deposition of clastic sediments initiated the movement of the underlying Zechstein evaporites. The deposition ceased during the Middle Jurassic, when the entire area was uplifted as a result of the Mid North Sea Doming. The uplift resulted in a pronounced erosion of Upper Triassic and Lower Jurassic strata. This event is marked by a clear angular unconformity on all the seismic sections. The region remained an area of non-deposition until the end of the Early Cretaceous, when the sedimentation resumed in the area. Throughout the Late Cretaceous the sedimentation took place under tectonic quiescence. Reactivated salt movement is observed at the Cretaceous Cenozoic transition as a result of the change from an extensional to compressional regional stress field. The vertical salt movement influenced the Cenozoic sedimentation and resulted in thin-skinned faulting. [ABSTRACT FROM AUTHOR]