Explore the vast range of titles available.

Populations in urban environments are extremely mobile throughout the day and in various weather conditions; accounting for this pedestrian mobility and security becomes high importance. Research into the security and stability of the pedestrian environment under exposure to critical water flows provides an essential knowledge base with which the associated hazard unto them can be critically evaluated. This research seeks to analyse degrees of hazard in relation to persons exposed to high-volume rain events in urban areas. Several human trials of critical urban flows were conducted in order to determine the stability limits of pedestrians, crossing through a water flow in a real-scale physic model. Additionally, the critical first step from a dry footpath into fast-flowing water is considered and an assessment of the tested subjects’ emotional responses when entering and crossing flooded roadways was carried out. Results from this study are compared with various proposed human stability criteria as well as alternatives proposed in other written works. The presented study offers a stability threshold focused on shallow depths and high-velocity conditions, the most common urban flooding conditions.

Este trabalho objetiva analisar o Encontro das Águas dos rios Negro e Solimões na perspectiva do geopatrimônio e seu potencial geoturístico na Amazônia.. A metodologia apoiou-se em levantamento bibliográfico, trabalhos de campo para identificação e caracterização da área a partir de preenchimento de ficha de inventário de locais de interesse hidrológico – hidrossítios, adaptada da proposta de Foleto e Costa (2021), e o potencial geoturístico do Encontro das Águas foi baseado em estudos desenvolvidos por Manosso (2012).  A relevância da temática e a carência de estudos a cerda de geopatimônio hidrológico, em especial na Amazônia, local da maior bacia hidrográfica, do maior rio em comprimento e de vários hidrossítos como o Encontro das Águas dos Rios Negro e Solimões. A pesquisa demonstrou que apesar do referido ponto ter ampla visibilidade e ser conhecido, ainda que por nome, este não possui instrumentos legais que de fato o protegem e salvaguardam de ser impactado. Do ponto de vista do geopatrimônio, o Encontro das Águas dos Rios Negro e Solimões tem de hidrossítio por apresentar valor de 76,45% pelo inventario de locais de interesse hidrológico. E sobre os fins geoturísticos, suas características podem ser bem aproveitadas para o ensino de geociências, uma vez que possibilita o ensino de fenômenos geológico-geomorfológicos, hidrológicos, das dinâmicas socioespaciais e Biodiversidade, para discentes (da educação básica e superior) e leigos, como os turistas. Logo, este artigo possui relevância, não só no avanço dos estudos relacionados à geodiversidade na Amazônia, mas também para a popularização do geoturismo neste contexto.

During the second week of September 2013, a seasonally uncharacteristic weather pattern stalled over the Rocky Mountain Front Range region of northern Colorado bringing with it copious amounts of moisture from the Gulf of Mexico, Caribbean Sea, and the tropical eastern Pacific Ocean. This feed of moisture was funneled toward the east-facing mountain slopes through a series of mesoscale circulation features, resulting in several days of unusually widespread heavy rainfall over steep mountainous terrain. Catastrophic flooding ensued within several Front Range river systems that washed away highways, destroyed towns, isolated communities, necessitated days of airborne evacuations, and resulted in eight fatalities. The impacts from heavy rainfall and flooding were felt over a broad region of northern Colorado leading to 18 counties being designated as federal disaster areas and resulting in damages exceeding $2 billion (U.S. dollars). This study explores the meteorological and hydrological ingredients that led to this extreme event. After providing a basic timeline of events, synoptic and mesoscale circulation features of the event are discussed. Particular focus is placed on documenting how circulation features, embedded within the larger synoptic flow, served to funnel moist inflow into the mountain front driving several days of sustained orographic precipitation. Operational and research networks of polarimetric radar and surface instrumentation were used to evaluate the cloud structures and dominant hydrometeor characteristics. The performance of several quantitative precipitation estimates, quantitative precipitation forecasts, and hydrological forecast products are also analyzed with the intention of identifying what monitoring and prediction tools worked and where further improvements are needed.

As flood impacts are increasing in large parts of the world, understanding the primary drivers of changes in risk is essential for effective adaptation. To gain more knowledge on the basis of empirical case studies, we analyze eight paired floods, that is, consecutive flood events that occurred in the same region, with the second flood causing significantly lower damage. These success stories of risk reduction were selected across different socioeconomic and hydro‐climatic contexts. The potential of societies to adapt is uncovered by describing triggered societal changes, as well as formal measures and spontaneous processes that reduced flood risk. This novel approach has the potential to build the basis for an international data collection and analysis effort to better understand and attribute changes in risk due to hydrological extremes in the framework of the IAHSs Panta Rhei initiative. Across all case studies, we find that lower damage caused by the second event was mainly due to significant reductions in vulnerability, for example, via raised risk awareness, preparedness, and improvements of organizational emergency management. Thus, vulnerability reduction plays an essential role for successful adaptation. Our work shows that there is a high potential to adapt, but there remains the challenge to stimulate measures that reduce vulnerability and risk in periods in which extreme events do not occur. Key Points Across different socio‐economic and hydro‐climatic contexts there is high potential to adapt to future flood risk Focusing events act as triggers for raising risk awareness, preparedness and improvements of emergency management which reduce vulnerability Vulnerability reduction is key for successful adaptation but the challenge remains to stimulate risk reduction when no extreme events occur

Managed aquifer recharge (MAR) can be affected by many risks. Those risks are related to different technical and non-technical aspects of recharge, like water availability, water quality, legislation, social issues, etc. Many other works have acknowledged risks of this nature theoretically; however, their quantification and definition has not been developed. In this study, the risk definition and quantification has been performed by means of “fault trees” and probabilistic risk assessment (PRA). We defined a fault tree with 65 basic events applicable to the operation phase. After that, we have applied this methodology to six different managed aquifer recharge sites located in the Mediterranean Basin (Portugal, Spain, Italy, Malta, and Israel). The probabilities of the basic events were defined by expert criteria, based on the knowledge of the different managers of the facilities. From that, we conclude that in all sites, the perception of the expert criteria of the non-technical aspects were as much or even more important than the technical aspects. Regarding the risk results, we observe that the total risk in three of the six sites was equal to or above 0.90. That would mean that the MAR facilities have a risk of failure equal to or higher than 90 % in the period of 2–6 years. The other three sites presented lower risks (75, 29, and 18 % for Malta, Menashe, and Serchio, respectively).

Soil moisture measurements are needed in a large number of applications such as hydro-climate approaches, watershed water balance management and irrigation scheduling. Nowadays, different kinds of methodologies exist for measuring soil moisture. Direct methods based on gravimetric sampling or time domain reflectometry (TDR) techniques measure soil moisture in a small volume of soil at few particular locations. This typically gives a poor description of the spatial distribution of soil moisture in relatively large agriculture fields. Remote sensing of soil moisture provides widespread coverage and can overcome this problem but suffers from other problems stemming from its low spatial resolution. In this context, the DISaggregation based on Physical And Theoretical scale CHange (DISPATCH) algorithm has been proposed in the literature to downscale soil moisture satellite data from 40 to 1¿km resolution by combining the low-resolution Soil Moisture Ocean Salinity (SMOS) satellite soil moisture data with the high-resolution Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST) datasets obtained from a Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. In this work, DISPATCH estimations are compared with soil moisture sensors and gravimetric measurements to validate the DISPATCH algorithm in an agricultural field during two different hydrologic scenarios: wet conditions driven by rainfall events and wet conditions driven by local sprinkler irrigation. Results show that the DISPATCH algorithm provides appropriate soil moisture estimates during general rainfall events but not when sprinkler irrigation generates occasional heterogeneity. In order to explain these differences, we have examined the spatial variability scales of NDVI and LST data, which are the input variables involved in the downscaling process. Sample variograms show that the spatial scales associated with the NDVI and LST properties are too large to represent the variations of the average soil moisture at the site, and this could be a reason why the DISPATCH algorithm does not work properly in this field site.

Temporary streams are those water courses that undergo the recurrent cessation of flow or the complete drying of their channel. The structure and composition of biological communities in temporary stream reaches are strongly dependent on the temporal changes of the aquatic habitats determined by the hydrological conditions. Therefore, the structural and functional characteristics of aquatic fauna to assess the ecological quality of a temporary stream reach cannot be used without taking into account the controls imposed by the hydrological regime. This paper develops methods for analysing temporary streams' aquatic regimes, based on the definition of six aquatic states that summarize the transient sets of mesohabitats occurring on a given reach at a particular moment, depending on the hydrological conditions: Hyperrheic, Eurheic, Oligorheic, Arheic, Hyporheic and Edaphic. When the hydrological conditions lead to a change in the aquatic state, the structure and composition of the aquatic community changes according to the new set of available habitats. We used the water discharge records from gauging stations or simulations with rainfall-runoff models to infer the temporal patterns of occurrence of these states in the Aquatic States Frequency Graph we developed. The visual analysis of this graph is complemented by the development of two metrics which describe the permanence of flow and the seasonal predictability of zero flow periods. Finally, a classification of temporary streams in four aquatic regimes in terms of their influence over the development of aquatic life is updated from the existing classifications, with stream aquatic regimes defined as Permanent, Temporary-pools, Temporary-dry and Episodic. While aquatic regimes describe the long-term overall variability of the hydrological conditions of the river section and have been used for many years by hydrologists and ecologists, aquatic states describe the availability of mesohabitats in given periods that determine the presence of different biotic assemblages. This novel concept links hydrological and ecological conditions in a unique way. All these methods were implemented with data from eight temporary streams around the Mediterranean within the MIRAGE project. Their application was a precondition to assessing the ecological quality of these streams.

A dinâmica de uso e ocupação da terra apresenta um padrão de impacto coincidente com áreas de maior vulnerabilidade hídrica (cabeceiras de bacias hidrográficas). O objetivo deste trabalho é investigar as características que influenciam a disponibilidade hídrica da Amazônica Oriental, associando as informações hidrológicas e as características de uso e cobertura da terra. A Região Hidrográfica do Atlântico Nordeste Ocidental (RHANO) possui uma área de aproximadamente 274.300 km². Adquiriu-se os dados de Temperatura da Superfície do Mar (TSM) da National Oceanic Atmospheric Administration; hidrometeorológicos da Agência Nacional das Águas; de interpolação pluviométrica do Global Precipitation Climatology Center e de uso e cobertura da terra do Ministério do Meio Ambiente. As anomalias de TSM apresentaram tendência de aquecimento do Atlântico e características térmicas alternadas para o Pacífico com relações identificadas nos extremos pluviométricos anuais. A RHANO apresentou o período chuvoso (Dez-Mai) e estiagem (Jun-Nov) bem definidos, com as maiores pluviosidades (noroeste) e os menores volumes pluviais (nordeste). A variabilidade fluviométrica apresentou 1 mês de defasagem em relação a precipitação. A estatística mostrou a relação mais forte entre as variáveis hidrológicas na bacia do rio Itapecuru e correlação mais fraca na bacia do rio Guamá-Capim, indicando possível influência da mudança do uso e ocupação desta região, apresentando alta heterogeneidade nas formas de cobertura. As informações obtidas indicaram forte tendência que as formas de uso e cobertura da terra estejam contribuindo para variar o grau de correlação das variáveis hidrológicas, além de serem impactadas pelas condicionantes climáticas, principalmente o ENOS.

\"Prediflood\" is a database of historical floods that occurred in Catalonia (NE Iberian Peninsula), between the 11th century and the 21st century. More than 2700 flood cases are catalogued, and more than 1100 flood events. This database contains information acquired under modern historiographical criteria and it is, therefore, suitable for use in multidisciplinary flood analysis techniques, such as meteorological or hydraulic reconstructions.

This study aims at evaluating the performances of flash-flood forecasts issued from deterministic and ensemble meteorological prognostic systems. The hydrometeorological modeling chain includes the Weather Research and Forecasting Model (WRF) forcing the rainfall-runoff model MARINE dedicated to flash floods. Two distinct ensemble prediction systems accounting for (i) perturbed initial and lateral boundary conditions of the meteorological state and (ii) mesoscale model physical parameterizations have been implemented on the Agly catchment of the eastern Pyrenees with three subcatchments exhibiting different rainfall regimes. Different evaluations of the performance of the hydrometeorological strategies have been performed: (i) verification of short-range ensemble prediction systems and corresponding streamflow forecasts, for a better understanding of how forecasts behave; (ii) usual measures derived from a contingency table approach, to test an alert threshold exceedance; and (iii) overall evaluation of the hydrometeorological chain using the continuous rank probability score, for a general quantification of the ensemble performances. Results show that the overall discharge forecast is improved by both ensemble strategies with respect to the deterministic forecast. Threshold exceedance detections for flood warning also benefit from large hydrometeorological ensemble spread. There are no substantial differences between both ensemble strategies on these test cases in terms of both the issuance of flood warnings and the overall performances, suggesting that both sources of external-scale uncertainty are important to take into account.