In contrast to the basic assumption of a homogeneous population underlying common approaches to flood frequency analysis, flood events often arise from different runoff‐generating processes. In many ...large river basins, the diversity of these processes within tributary basins and the superposition of their flood waves increase the complexity of statistical flood modeling. Under these circumstances, the allocation of the most effective flood protection measures requires a spatially explicit analysis of flood‐generating processes and the determination of the probability of downstream flood scenarios. For large basins, flood scenarios are often derived using individual historical floods along with model‐based simulations. We, instead, performed hydrograph‐based flood‐type classification and volume‐based runoff analyses for the Upper Danube River to estimate the contributions of subbasins to floods at downstream locations. Using this information, we generated long synthetic samples of peak‐volume‐pairs to apply a multivariate statistical flood‐frequency model that yields a conditional probability of a flood peak given the peaks in tributary stations. The results show that only certain combinations of flood types may result in extreme peaks downstream of confluences. They also highlight the need to distinguish runoff‐generation mechanisms for the larger floods from ones that drive smaller, more frequent events. Through an example with the Rhine River, we demonstrate how the statistical model can be generalized for complex river networks featuring several tributary confluences. Finally, design floods for different scenarios of flood‐type combinations and assigned probabilities are derived, an approach that can be used to possible climate impacts to flood frequency.
Key Points
Flood events are characterized by the nature of runoff‐generating precipitation events and distributions of runoff volumes among tributaries
A statistical simulation generates peak‐volume pairs based on flood types at confluences, consistently for upstream and downstream gauges
Vine copulas are used to estimate most probable combinations of flood types and superposition for downstream events of given return periods
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•We develop a methodology for considering heterogeneity of buildings and land use.•We define modelling levels to add urban features stepwise based on OSM data.•Spatial heterogeneity ...of urban features has a medium–high impact on overland flood.•The addition of multiple urban features have a higher cumulative effect.
Some of the major challenges in modelling rainfall–runoff in urbanised areas are the complex interaction between the sewer system and the overland surface, and the spatial heterogeneity of the urban key features. The former requires the sewer network and the system of surface flow paths to be solved simultaneously. The latter is still an unresolved issue because the heterogeneity of runoff formation requires high detailed information and includes a large variety of feature specific rainfall–runoff dynamics. This paper discloses a methodology for considering the variability of building types and the spatial heterogeneity of land surfaces. The former is achieved by developing a specific conceptual rainfall–runoff model and the latter by defining a fully distributed approach for infiltration processes in urban areas with limited storage capacity dependent on OpenStreetMaps (OSM). The model complexity is increased stepwise by adding components to an existing 2D overland flow model. The different steps are defined as modelling levels. The methodology is applied in a German case study. Results highlight that: (a) spatial heterogeneity of urban features has a medium to high impact on the estimated overland flood-depths, (b) the addition of multiple urban features have a higher cumulative effect due to the dynamic effects simulated by the model, (c) connecting the runoff from buildings to the sewer contributes to the non-linear effects observed on the overland flood-depths, and (d) OSM data is useful in identifying pounding areas (for which infiltration plays a decisive role) and permeable natural surface flow paths (which delay the flood propagation).
Flood risk emerges from the interaction of hazard and vulnerability. Over recent decades the notion of risk being the basis for flood management decisions has become widely accepted and ...operationalised through the use of models and quantified risk analysis providing the evidence for risk-informed decision making. However, it is now abundantly apparent that changes in time, at a range of scales, of pertinent variables that determine risk are not a second order consideration but, instead, fundamentally challenge the conventional approach to flood risk management. The nature of some of these changes, particularly those that operate on extended timescales, are highly uncertain, yet decisions that may have implications for several decades still have to be taken. In this paper we explore how flood risk management may be adapted to address processes of uncertain future change. We identify a range of levels at which change may be incorporated in decision making: in the representation of uncertain non-stationary quantities; in the rules that are used to identify preferred options; in the variety of options that may be contemplated for flood risk management; in the scope of problem definition, which increasingly extends to address multiple hazards and multiple functions of river basins; and in the social and organizational characteristics that promote adaptive capacity. Integrated responses to changing flood risk need to attend to each of these levels of decision making, from the technicalities of non-stationarity, to the promotion of resilient societies.
This paper presents a new reconstruction of the 20th century global hydrography using fully coupled water balance and transport model in a flexible modeling framework. The modeling framework allows a ...high level of configurability both in terms of input forcings and model structure. Spatial and temporal trends in hydrological cycle components are assessed under "pre-industrial" conditions (without modern-day human activities) and contemporary conditions (incorporating the effects of irrigation and reservoir operations). The two sets of simulations allow the isolation of the trends arising from variations in the climate input driver alone and from human interventions. The sensitivity of the results to variations in input data was tested by using three global gridded datasets of precipitation. Our findings confirm that the expansion of irrigation and the construction of reservoirs has significantly and gradually impacted hydrological components in individual river basins. Variations in the volume of water entering the oceans annually, however, are governed primarily by variations in the climate signal alone with human activities playing a minor role. Globally, we do not find a significant trend in the terrestrial discharge over the last century. The largest impact of human intervention on the hydrological cycle arises from the operation of reservoirs that drastically changes the seasonal pattern of horizontal water transport in the river system and thereby directly and indirectly affects a number of processes such as ability to decompose organic matter or the cycling of nutrients in the river system.
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•We develop a parallel 2D diffusive wave model in Matlab and Fortan.•We achieved speed-up times ranging from 1.2 to 5.2 using 2 to 12 processors.•The variable time step method and the ...process for Wet–Dry fronts kept the solution stable.•Absolute mass conservation is obtained in all seven tests used to validate the model.
Growing advances in remote sensing technologies together with the widespread availability of Digital terrain models (DTM) have intensified the research into two-dimensional (2D) models. Supported by detailed DTM, 2D models can become very accurate tools yet not without an added cost on the computational effort. Floodplain inundation is characterised by a slow varying phenomenon which can last hours, days or even weeks. In this paper we aim to develop a specific parallel diffusive wave model with variable time step suitable for flood inundation. Taking advantage of up to 12 processors, speed-up times ranging from 1.7 to 5.2 and 1.2 to 1.7 are achieved with the Matlab parallel computing toolbox and Fortran OpenMP Application Programming, respectively. The variable time method and the process devised to represent Wet–Dry fronts kept the solution stable and preserved absolute mass conservation. P-DWave performed well against known analytical solutions and dynamic and diffusive models in a total of seven tests.
Previous studies suggest that flood-rich and flood-poor periods are present in many flood peak discharge series around the globe. Understanding the occurrence of these periods and their driving ...mechanisms is important for reliably estimating future flood probabilities. We propose a method for detecting flood-rich and flood-poor periods in peak-over-threshold series based on scan-statistics and combine it with a flood typology in order to attribute the periods to their flood-generating mechanisms. The method is applied to 164 observed flood series in southern Germany from 1930 to 2018. The results reveal significant flood-rich periods of heavy-rainfall floods, especially in the Danube river basin in the most recent decades. These are consistent with trend analyses from the literature. Additionally, significant flood-poor periods of snowmelt-floods in the immediate past were detected, especially for low-elevation catchments in the alpine foreland and the uplands. The occurrence of flood-rich and flood-poor periods is interpreted in terms of increases in the frequency of heavy rainfall in the alpine foreland and decreases of both soil moisture and snow cover in the midlands.
CFTR, the cystic fibrosis (CF) gene, encodes for the CFTR protein that plays an essential role in anion regulation and tissue homeostasis of various epithelia. In the gastrointestinal (GI) tract CFTR ...promotes chloride and bicarbonate secretion, playing an essential role in ion and acid-base homeostasis. Cftr has been identified as a candidate driver gene for colorectal cancer (CRC) in several Sleeping Beauty DNA transposon-based forward genetic screens in mice. Further, recent epidemiological and clinical studies indicate that CF patients are at high risk for developing tumors in the colon. To investigate the effects of CFTR dysregulation on GI cancer, we generated Apc(Min) mice that carried an intestinal-specific knockout of Cftr. Our results indicate that Cftr is a tumor suppressor gene in the intestinal tract as Cftr mutant mice developed significantly more tumors in the colon and the entire small intestine. In Apc(+/+) mice aged to ~1 year, Cftr deficiency alone caused the development of intestinal tumors in >60% of mice. Colon organoid formation was significantly increased in organoids created from Cftr mutant mice compared with wild-type controls, suggesting a potential role of Cftr in regulating the intestinal stem cell compartment. Microarray data from the Cftr-deficient colon and the small intestine identified dysregulated genes that belong to groups of immune response, ion channel, intestinal stem cell and other growth signaling regulators. These associated clusters of genes were confirmed by pathway analysis using Ingenuity Pathway Analysis and gene set enrichment analysis (GSEA). We also conducted RNA Seq analysis of tumors from Apc(+/+) Cftr knockout mice and identified sets of genes dysregulated in tumors including altered Wnt β-catenin target genes. Finally we analyzed expression of CFTR in early stage human CRC patients stratified by risk of recurrence and found that loss of expression of CFTR was significantly associated with poor disease-free survival.
Abstract Background The unfavourable side-effects of late-stage pancreatic cancer treatments call for non-toxic and effective therapeutic approaches. We compared the overall survival (OS) of patients ...receiving an extract of Viscum album L. (VaL) or no antineoplastic therapy. Methods This is a prospective, parallel, open label, monocentre, group-sequential, randomised phase III study. Patients with locally advanced or metastatic cancer of the pancreas were stratified according to a binary prognosis index, composed of tumour stage, age and performance status; and were evenly randomised to subcutaneous injections of VaL extracts or no antineoplastic therapy (control). VaL was applied in a dose-escalating manner from 0.01 mg up to 10 mg three times per week. Patients in both groups received best supportive care. The primary end-point was 12-month OS, assessed in a group-sequential analysis. Findings We present the first interim analysis, including data from 220 patients. Baseline characteristics were well balanced between the study arms. Median OS was 4.8 for VaL and 2.7 months for control patients (prognosis-adjusted hazard ratio, HR = 0.49; p < 0.0001). Within the ‘good’ prognosis subgroup, median OS was 6.6 versus 3.2 months (HR = 0.43; p < 0.0001), within the ‘poor’ prognosis subgroup, it was 3.4 versus 2.0 months respectively (HR = 0.55; p = 0.0031). No VaL-related adverse events were observed. Conclusion VaL therapy showed a significant and clinically relevant prolongation of OS. The study findings suggest VaL to be a non-toxic and effective second-line therapy that offers a prolongation of OS as well as less disease-related symptoms for patients with locally advanced or metastatic pancreatic cancer.
Species identification is fundamental to all aspects of biology and conservation. The process can be challenging, particularly in groups including many closely related or similar species. The problem ...is confounded by the absence of an up-to-date taxonomic revision, but even with such a resource all but professional botanists may struggle to recognise key species, presenting a substantial barrier to vital work such as surveys, threat assessments, and seed collection for ex situ conservation. Genus
: An Identification Aid is a tool to help both amateurs and professionals identify (using a limited number of accessible characteristics) and find information about the 851 species and many subspecific taxa of the genus
. We present an updated version 4.00, with new features including integrating distribution data from GBIF and iNaturalist, links to taxonomic resources through World Flora Online, and a probability function for identifications, that is freely available for PCs. It remains a work in progress: We discuss routes forward for collaboratively improving this resource.
Range verification and dose monitoring in proton therapy is considered as highly desirable. Different methods have been developed worldwide, like particle therapy positron emission tomography ...(PT-PET) and prompt gamma imaging (PGI). In general, these methods allow for a verification of the proton range. However, quantification of the dose from these measurements remains challenging. For the first time, we present an approach for estimating the dose from prompt γ-ray emission profiles. It combines a filtering procedure based on Gaussian-powerlaw convolution with an evolutionary algorithm. By means of convolving depth dose profiles with an appropriate filter kernel, prompt γ-ray depth profiles are obtained. In order to reverse this step, the evolutionary algorithm is applied. The feasibility of this approach is demonstrated for a spread-out Bragg-peak in a water target.
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