Watershed Event Research Articles

Transferability of machine-learning-based modeling frameworks across flood events for hindcasting maximum river water depths in coastal watersheds

Abstract. Despite applications of machine learning (ML) models for predicting floods, their transferability for out-of-sample data has not been explored. This paper developed an ML-based model for hindcasting maximum river water depths during major events in coastal watersheds and evaluated its transferability across other events (out-of-sample). The model considered the spatial distribution of influential factors that explain the underlying physical processes to hindcast maximum river water depths. Our model evaluations in a six-digit hydrologic unity code (HUC6) watershed in the northeastern USA showed that the model satisfactorily hindcasted maximum water depths at 116 stream gauges during a major flood event, Hurricane Ida (R2 of 0.94). The pre-trained, validated model was successfully transferred to three other major flood events, hurricanes Isaias, Sandy, and Irene (R2>0.70). Our results showed that ML-based models can be transferable for hindcasting maximum river water depths across events when informed by the spatial distribution of pertinent features, their interactions, and underlying physical processes in coastal watersheds.

Using Doppler duplex ultrasound to determine hemodynamic alterations in renal vasculature: Crucial pathophysiological event preceding renal dysfunction in decompensated cirrhosis

BackgroundRenal dysfunction is a watershed event in cirrhosis, often preceded by renal vasoconstriction. However, our reliability on elevated serum creatinine often delays interventions. Measurement of Renal Resistive Index (RI) and Renal Venous Stasis Index (RVSI) by Doppler ultrasound offers insight into renal vasoconstriction. MethodsFifty participants with decompensated cirrhosis with ascites and normal serum creatinine underwent renal Doppler ultrasound for the measurement of RI and RVSI. All patients were compliant with a salt-restricted diet. Individuals aged <18 years, hepatocellular carcinoma, non-cirrhosis-related ascites, pre-existing renal disease, obstructive uropathy, or history of nephrotoxic medication use were excluded. Statistical analyses, including Pearson correlation, regression analysis, and Chi-square/Fisher’s exact tests, were performed to assess the statistical significance between RI, RVSI, and renal parameters. Additionally, the association of RI with the model for end-stage liver disease sodium (MELD-Na) and Child-Turcotte-Pugh (CTP) scores was also assessed. ResultsMajority were males (88%), average CTP score was 11.7, mean MELD-Na score was 20.92, and mean serum creatinine was 1.05 mg/dL. Renal parameters had varying RI values among renal arteries, with the main right and left arteries at 0.615 [standard deviation (SD): 0.089] and 0.638 (SD: 0.083), respectively. RI and RVSI are significantly correlated with serum creatinine. Further, significant correlation between, RI, RVSI values noted with MELD-Na score even when serum creatinine values are normal. ConclusionStrong correlations between serum creatinine, RI, and MELD-Na scores hints at predictive clinical potential. Future research with larger cohorts and extended follow-up is required to gauge clinical utility and its impact on outcomes.

Big Disaster from Small Watershed: Insights into the Failure and Disaster-Causing Mechanism of a Debris Flow on 25 September 2021 in Tianquan, China

The occurrence of debris flow events in small-scale watersheds with dense vegetation in mountainous areas that result in significant loss of life and missing individuals challenges our understanding and expertise in investigating and preventing these disasters. This has raised concerns about the occurrence of large debris flow disasters from small watersheds. This study focused on a catastrophic debris flow that took place in Longtou Gully (0.45 km2) in Tianquan County, Ya’an City on 25 September 2021, which resulted in 14 deaths and missing individuals. Through comprehensive field investigations, high-precision remote sensing data analyses, and numerical simulations, we analyzed the triggering mechanisms and dynamic processes of this event. Our results indicate that the convergence hollow at the channel head exhibited higher hydraulic conditions during rainfall compared to gentle slopes and convex terrains, leading to the instability of colluvial soil due to the expansion of the saturated zone near the soil–bedrock interface. The entrainment of material eroded from the channel resulted in an approximately 4.7 times increase in volume, and the channel scarp with a height of about 200 m amplified the destructive power of the debris flow. We emphasize the need to take seriously the possibility of catastrophic debris flows in small-scale watersheds, with colluvial deposits in hollows at the channel head under vegetation cover that serve as precursor material sources, and the presence of channel scarps formed by changes in the incision rate of the main river, which is common in the small watershed on both sides. This study provides insights for risk assessment of debris flows in small-scale catchments with dense vegetation cover in mountainous areas, highlighting the importance of vigilance in addressing disasters in small-scale catchments, particularly in regions with increasing human–environment conflicts.

The 17 January 1994 Northridge, California, Earthquake: A Retrospective Analysis

Abstract The 17 January 1994 Northridge, California, earthquake was a watershed event with far-reaching societal and scientific impacts. The earthquake, which occurred in the early days of both broadband seismic networks and the Internet, spurred advances in seismic monitoring, real-time systems, and development of data products. Motivated by the 30th anniversary of the earthquake, we present a brief retrospective of the earthquake and its impact, and reconsider both ground motions and the aftershock distribution using modern tools and the best-available data. With improvements in instrumentation and analysis methodology, recent earthquakes continue to reveal the increasing complexity of ground motions, fault systems, and earthquake ruptures. Even in the absence of data from state-of-the-art instrumentation, a retrospective consideration of ground-motion data from the Northridge earthquake reveals complexities beyond what could be characterized (and modeled) 30 yr ago. Aftershock relocations for both the 1971 Sylmar and 1994 Northridge earthquakes also reveal an updated view of fault complexity. Our study does provide a cautionary tale regarding legacy data sets and research results that are not easily accessible, which can result in discrepancies between catalog data and products from the best available science. We also briefly describe outreach products produced as a part of the anniversary commemoration.

Limited effect of the confluence angle and tributary gradient on Alpine confluence morphodynamics under intense sediment loads

Abstract. Confluences are dynamic morphological nodes that are found in all river networks. In mountain regions, they are influenced by hydraulic and sedimentary processes that occur in steep channels during extreme events in small watersheds. Sediment transport in the tributary channel and aggradation in the confluence can be massive, potentially causing overbank flooding and sedimentation into adjacent settlement areas. Previous works dealing with confluences have mainly focused on lowland regions, and those that have focused on mountain areas have used sediment concentrations and channel gradients that are largely under-representative of mountain river conditions. The presented work contributes to filling this research gap with 45 experiments that use a large-scale physical model. Geometric model parameters, the applied grain size distribution, and the considered discharges represent the conditions at 135 confluences in South Tyrol (Italy) and Tyrol (Austria). The experimental program allowed for a comprehensive analysis of the effects of (i) the confluence angle, (ii) the tributary gradient, (iii) the channel discharges, and (iv) the tributary sediment concentration. In contrast to most research dealing with confluences, results indicate that, in the presence of an intense tributary sediment supply and a small tributary-to-main-channel discharge ratio (0.1), the confluence angle does not have a decisive effect on confluence morphology. Adjustments to the tributary channel gradient yielded the same results. A reoccurring range of depositional geomorphic units was observed in which a deposition cone transitioned to a bank-attached bar. The confluence morphology and tributary channel gradient rapidly adjusted, tending towards an equilibrium state to accommodate both water discharges and the sediment load from the tributary. Statistical analyses demonstrated that the confluence morphology was controlled by the combined channel discharge and the depositional or erosional extent was controlled by the sediment concentration. Applying conclusions drawn from lowland confluence dynamics could misrepresent depositional and erosional patterns and the related flood hazard at mountain river confluences.

The Evolution of a Contemporary Iraqi Intellectual: Reflections on Ahmed Saadawi's First Four Novels

This article focuses on Iraqi writer Ahmad Saadawi's first four novels, which were authored over a period of roughly two decades during the last years of the Ba'th Party regime and after its toppling in 2003. These literary narratives are addressed as a reflection of Saadawi's intellectual development. The article shows that, more than anything else, the sectarian civil war of 2006–7 was a watershed event for his literary work.

Interpreting and modelling the daily extreme sediment events in karst mountain watersheds

Increasingly frequent extreme rainfall as a result of climate change is strongly damaging the global soil and water environment. However, few studies have focused on daily extreme sediment events (DESE) in heterogeneous karst watersheds based on long-term in-situ observations. This study quantitatively assessed the time effect of DESE on rainfall response, decoupled the impact of environmental factors on DESE by using structural equation modelling, and finally explored the modelling scheme of DESE based on the hybrid model. The results showed that DESE had the highest frequency of occurrence in May–July, with dispersed distribution in the value domain. Rainfall with a time lag of 1 day and a time accumulation of 2 or 3 days was an important contribution to DESE (P < 0.01, R = 0.47–0.68). Combined effects of environmental factors explained 53.6 %–64.1 % of the variation in DESE. Runoff and vegetation exerted the strongest direct and indirect effects on DESE, respectively (β = 0.66/−0.727). Vegetation was the dominant driver of DESE in Dabanghe and Yejihe (β = −0.725/−0.758), while the dominant driver in Tongzhihe was climate (β = 0.743). In the future, the risk of extreme sediments should be prevented and resolved through the comprehensive regulation of multiple paths, such as runoff and vegetation. Hybrid models significantly improved the modelling performance of machine learning models. Generalized additive model-Extreme gradient boost had the best performance, while Partial least squares regression-Extreme gradient boost was the most valuable when considering performance and input data cost. Two methods can be used as recommended solutions for DESE modelling. This study provides new and in-depth insights into DESE in karst watersheds and helps the region develop forward-looking soil and water management models to cope with future extreme erosion hazards.

Global prediction of extreme floods in ungauged watersheds

Floods are one of the most common natural disasters, with a disproportionate impact in developing countries that often lack dense streamflow gauge networks1. Accurate and timely warnings are critical for mitigating flood risks2, but hydrological simulation models typically must be calibrated to long data records in each watershed. Here we show that artificial intelligence-based forecasting achieves reliability in predicting extreme riverine events in ungauged watersheds at up to a five-day lead time that is similar to or better than the reliability of nowcasts (zero-day lead time) from a current state-of-the-art global modelling system (the Copernicus Emergency Management Service Global Flood Awareness System). In addition, we achieve accuracies over five-year return period events that are similar to or better than current accuracies over one-year return period events. This means that artificial intelligence can provide flood warnings earlier and over larger and more impactful events in ungauged basins. The model developed here was incorporated into an operational early warning system that produces publicly available (free and open) forecasts in real time in over 80 countries. This work highlights a need for increasing the availability of hydrological data to continue to improve global access to reliable flood warnings.

Perso-Sanskrit Narratives of the Mughal’s Tasḵẖīr-i-kashmir: Phased Opening, Ecology and Literary Strategies

This study explores the Mughal conquest of Kashmir (tasḵẖīr-i-kashmīr) through the region’s phased openings rather than a singular watershed event signalling either a climactic loss of independence or ushering in a golden age. Before 1585–89, there were two decades of patronage, diplomacy, and a steady breaching of the valley’s defences. When Mughal dominion was established, sections of the local aristocracy figured prominently as part of the new dispensation of power, while others continued to offer resistance. An analysis of imperial and local Perso-Sanskrit narratives of the conquest yields insight into how Kashmir was incorporated into the Mughal empire. This micro-historical process is the most valorised of historical transitions within the early Mughal literary discourse, it was highly represented as moment of glory and grand vehicle for rhetoric of diplomatic propaganda. This study largely demonstrates pre-modern power elites’ graded political loyalties, multi-laterality of socio-historical and ecological processes that facilitated the Mughal kingdom-seizing in Kashmir. Simultaneously moving beyond the traditional binary of ‘conquest’ vs ‘resistance’ conceptualisation and political abuse of the local narratives, it navigates the analytical efficacy and social logic of five primary narrative constructions of the Conquest produced by Mughal political elites and regional counter-elites in the terminal decade of sixteenth and early decades of the seventeenth century, namely, Akbarnāmā, Insha’ Abū’l Faẓl, Śukha-rājataraṅgiṇī, Bāhāristān-i-Sháhi and Taʼrīḵẖ-i-Kashmir.

The Xicaque before Spanish Rule in Leán y Mulia, Honduras

Abstract In the late seventeenth century the Spanish colonial administration began to issue decrees that sought to implement the familiar colonial policies of entrada, reducción, and misión within an unconquered region of the Province of Honduras called by the Spanish Leán y Mulia. After a few short-lived settlements in the early part of the eighteenth century, a new wave of Franciscans began attempts to convert the Xicaque of Leán y Mulia in 1747–54. In 1751 the onset of a smallpox epidemic at the Franciscan misiones became the watershed event that defined subsequent interaction between the Spanish and the Xicaque and, because of this, defined Spanish policy within the region of Leán y Mulia. A fear of contracting the disease would subsequently linger in the memory of the Xicaque at the misiones and in Leán y Mulia. This dread of disease and sickness predetermined subsequent social relationships between the Xicaque and the Spanish settlers who sought their indoctrination and acculturation in subsequent decades of the eighteenth and nineteenth century with no success.

BOOK REVIEW: Sri Lanka's Easter Sunday Massacre: Lessons for International Community by Rohan Gunaratna

Rohan Gunaratna's recent publication titled Sri Lanka’s Easter Sunday Massacre: Lessons for International Community tries to explore the “Easter Attack massacre” and its root causes in Sri Lanka. The work would indeed become one of the main references for those interested in exploring the sources and roots of the Easter Attack. Although the Easter Sunday massacre was a watershed event in Sri Lankan history as well as the ‘September 11’ of Sri Lankan Muslims, there has been a lack of detailed analysis on the subject thus far. In this sense, Gunaratna's work could be seen as the first detailed study of the tragedy, elaborating on the background of the bombers, their preparations, and the execution. In the aftermath of the attack, there has been a serious public debate on the nature of tragedy and its root causes. Participating in this debate, Imthiyaz Razak argued that the Easter attacks were a by-product of both “violence against Muslims since 2012”, unleashed by the Sinhala-Buddhist extremists and cultural exclusivism of Muslims, enabled by the political bargaining between the majoritarian state and minority political elites. For his part, Rajan Hoole argued in his work Sri Lanka's Easter Tragedy that the Easter Attack was the result of the entrenched phenomenon of the deep state that tries to manipulate religious extremists for their political ends. For him, the Easter Attack was more political than ideological. However, Gunaratna stressed the point that the Easter Attack directly resulted from the religious radicalization of a segment of the Muslim community in Sri Lanka, who embraced the Salafi-Wahhabism ideology of political Islam. The book elaborates this argument through a lengthy introduction and subsequent four chapters.

Social Memory, Public Memory, and Marginality: The Case of the “Death in Migration”

Memory is a source of ‘immunization’ for individuals (psycho-cognitive memory and biological immune system) and for communities (De Martino). We can consider culture as the memory of society. Particularly, the cultural memory of disasters plays a fundamental role. Ideally, it should help to reduce the vulnerability of societies to the risks of recurrence of natural/technological/social catastrophic events. However, memory is not an exact process, but a selective and reconstructive one (Bartlett). Furthermore, the memory of society is multiple and continuously exposed to the risk of distortions, interpretations, and manipulations. Social memory (Halbwachs) is the broader sphere of communicability that delimits the arena in which the different collective memories (of groups) compete for the relevance and plausibility of their own discourses. It will correspond, with good approximation, to the term “public memory”. In particular, the media and journalism play a very important function, as public memory is a memory of the public sphere (Habermas) and, somehow, the public sphere is itself memory (Jedlowski). This presentation aims to compare two social memories of a single catastrophic event in which a marginal social category was involved: migrants illegally crossing the Mediterranean Sea. The research focus concerns a watershed event of the recent migratory phenomenon: the Lampedusa shipwreck that took place on the 3&lt;sup&gt;rd&lt;/sup&gt; October 2013. The goal is to show how collective and public memory contrast each other. We will discuss two cultural and communicative processes located along the oppositional materialization/dematerialization axis. In the article we will reinterpret the evidence collected in the research carried out in 2014 on the Lampedusa shipwreck that took place on 3 October 2013 in order to reflect on the dynamics between different types of memories in the framework of the memory of disasters. We assume that they can be deeply distortive as they promote interrelated memory bias.

Covid-19 and Exposed to Vulnerabilities in The Creative Economy: Get Up Or Give Up

Academic literature extensively acknowledges the fragile character of creative and cultural activity. However, it has frequently been invisible to policymakers and decision-makers. As soon as Covid-19 began affecting local and national economies worldwide, numerous business and policy organizations hastened to research the impact of Covid-19 on the creative and cultural industries (CCIs) and their workforce. The report provides insight into these organizations' primary issues through a meta-analysis of the current survey and research programs in the United Kingdom. The findings shed light on prevalent concerns regarding visible and unseen challenges that require attention in this area. The study continues by debating if Covid-19 represents a watershed event for the sector or merely reveals the unsustainable cost of creative and cultural activity.

History from the Dustbins

In this essay, I reflect on the growing political obstacles to doing business history in China and how, in my doctoral dissertation research, I attempted to overcome them. More specifically, I discuss how I drew on unconventional historical sources and novel data to examine the relationship between informal entrepreneurial activity and economic change in Maoist China (1949–1978). Through the quantitative analysis of thousands of case files of individuals prosecuted as “speculators and profiteers”—discarded administrative documents that were recovered from Chinese flea markets—I reassessed the scale and scope of informal entrepreneurial activity in Maoist China. I then went on to triangulate these data with evidence found in other sources to illustrate how, over time, informal entrepreneurial activity became more collusive, encompassing, and impossible to contain. Ultimately, I argued that China’s “Reform and Opening Up” was not the state-led watershed event that it is often made out to be; rather, economic and institutional change was, at least partly, the result of a bottom-up transformation, decades in the making. This essay thus suggests that the use of unconventional sources and mixed methods presents opportunities both for doing research in contexts where history is being actively securitized and for producing countervailing narratives that decenter the state.

Backwater Effects in Rivers and Lakes: Case Study of Dongping Lake in China

In the context of global climate change, the frequency of watershed flooding events resulting from extreme rainfall has significantly increased. Especially at river or lake confluences, the presence of backwater effects greatly amplifies the flood risk. To investigate the influence of backwater effects on the hydraulic characteristics of rivers and lakes, this study focuses on the Dongping Lake in China. An enhanced two-dimensional hydrodynamic model was employed to simulate and analyze three different degrees of backwater effects. The results indicate that, compared to the working conditions without the backwater effect, the highest lake water level increased by 1.0 m and 0.1 m under severe and moderate backwater effect conditions, respectively. The total outflow flood volume decreased by 30.1% and 2.3%, respectively. The demolition time for the Jinshan Dam needs to be advanced by 12.5 h and 10.0 h, respectively, and the inundation area in the western region expanded by 2.73% and 0.32%. Additionally, the average inundation depth increased by 0.93 m and 0.08 m, respectively. These results provide valuable data support for the safe operation of Dongping Lake, the formulation of flood defense strategies, and, likewise, offer valuable insights into the risk management of flood events in other rivers and lakes with backwater effects.

The Immigrant Backstories of Asian American Surgeons.

The stories of Asian immigrants have both shared themes and ones that are unique to the histories of their homelands. Their labor was essential to the settlement and economic development of America, yet their presence incited riots and official restrictions to their rights to immigration and citizenship. Chinese laborers mined the Gold Country, built the transcontinental railroad, and reclaimed tillable land in the Central Valley. Yet they were denied the immense bounty they created, and their immigration was blocked by the Chinese Exclusion Act of 1882.Japanese, Asian Indians, and Filipinos replaced them on farms as migrant laborers. As foreign nationals they were not allowed to own land, but they thrived as independent farmers on leased plots. Their success attracted discrimination and racist violence. They, too, were barred from immigration and citizenship (Johnson-Reed Act, 1924).World War II was a watershed event for Asians in America. Japanese Americans, ethnically identical to the enemy, were imprisoned in concentration camps in the American interior. China, the Philippines, and India, all allies of the US, were rewarded with naturalization rights for their nationals. In 1965 Congress liberalized immigration quotas and reversed the 1924 restrictions, with priority given to those with advanced technical ability in science, including medicine. Asians from Taiwan and India took advantage of the new regulations and predominated among the newcomers. After the fall of Saigon in 1975, America accommodated yet another Asian population in the country, the tens of thousands of refugees from Southeast Asia.

In forma pauperis: Indentured Servitude, the Right to Counsel, and White Citizenship in the Seventeenth-Century Chesapeake

Abstract Indentured servitude was an exploitative form of coerced labor in England’s American colonies, but indentured servants were expected to join settler society after completing their terms of indenture, and they possessed clearly defined legal rights and protections in both English and colonial laws, even during their period of servitude. The masters and mistresses of indentured servants sometimes engaged in physical abuse and contractual fraud, but servants could sue their masters or mistresses in court without owing fees, a status termed in forma pauperis. Courts facilitated servant lawsuits and heeded procedural fairness, bringing in compensated witnesses, searching archival records, and even providing pro bono lawyers. It appears that most servants won their cases against their masters and mistresses, obtaining their freedom, their withheld freedom dues, or reimbursement for overlong terms of servitude. Indentured servants’ lawyers affirmed that their clients were rights-bearing members of society, persuasively utilizing terms such as ‘justice’ and ‘equity’ to represent their cases. The access of servants to legal recourse, the courts’ commitment to ensure due process and legal representation, and the frequent victories of servants over their masters demonstrated that indentured servants were regarded as valued members of colonial society in the Chesapeake, and in other colonial regions. Unlike enslaved people, who possessed neither legal rights nor access to the courts, white indentured servants possessed inherent, though limited, rights of freeborn subjects, even if from disenfranchised groups, such as women, children, or those of Irish origin. The legal and social distinctions between servitude and slavery began arising half a century before Bacon’s Rebellion in the 1670s, which is conventionally assumed to be a watershed event in the division between indentured servitude and slavery. The affirmation of the rights of indentured servants developed in parallel with the growth of slavery, and contributed to developing ideals of white citizenship.

Lessons in Failure: Mavoch (1967) and the Labyrinth-Based Exhibition in Israel

In 1967, the Israel Museum in Jerusalem launched Mavoch with great fanfare. Despite its innovative vision, critics swiftly dismissed the exhibition, and both the curator and the artists labelled it a failed experiment. This article revisits Mavoch to consider it as a watershed event in Israeli exhibitionary practice. The show is examined in a broader discussion on the genre of labyrinth-based exhibitions on which Mavoch was based. This genre, stemming from the surrealists’ shows in the 1930s and reaching its apex in Europe in the 1960s, heralded a shift in the concept of the museum from an object-oriented space to a dynamic venue of social participation. This article unravels the reasons behind the perceived failure of Mavoch and offers insights on the implementation of western display models in geographical and cultural peripheries.

STATE BANK OF INDIA: A HISTORICAL APPRAISAL OF CONTRIBUTIONS AND POST-DEMONETIZATION ECONOMIC TRANSFORMATIONS

The current study traces the history of the State Bank of India (SBI) from its colonial roots to its current function as a catalyst for India’s economic progress. SBIs progress parallels the expansion of the country, handling obstacles and transitions. Notably, the post-demonetization phase catapulted SBI into a pivotal role, propelling digitalization and financial inclusion. The impact of demonetization was a watershed event for SBI, reinforcing its commitment to innovation and changing its approach to financial services. SBI, via its technical skill and agility, not only accepted but also used change to improve client experiences and operational efficiency, cementing its history as a dynamic and prominent institution in the countrys banking sector. KEYWORDS: State Bank of India, Bank, Banking History, Bank Services, Demonetization

The Hot Vojvodina Summer Of 1988: Did Vojvodinians Seek to Overthrow Their Government?

Abstract Several watershed events preceded the dissolution of Yugoslavia. One of these was the toppling of the Vojvodina autonomist leadership in October 1988. This was preceded by a series of rallies throughout Vojvodina in the summer of 1988, which may have seemed like a spontaneous affair and the work of “ordinary citizens.” It was called “the antibureaucratic revolution.” However, these rallies, including a standing group of demonstrators, continually and always referring to the grievances of Kosovo Serbs, turned out to be supported by the Serbian political elite centered in Belgrade. The elite, still headed by the Serbian Communist Chief Slobodan Milošević, gave thrust and coordination to efforts to organize the rallies. The Vojvodina leadership was toppled for their alleged “failing to understand the plight of Kosovo Serbs.” The overthrow was, further, with a view to achieve the Serbian elite’s pet project, the “united Serbia”—that is, doing away with Vojvodina’s and Kosovo’s autonomy. Written sources (including recollections by Yugoslav leaders of the time) and written sources are considered in research on the events.