Prediction of local scour depth at bridge piers under clear-water and live-bed conditions: comparison of literature formulae and artificial neural networks

The scouring effect of the flowing water around bridge piers may undermine the stability of the structure, leading to extremely high direct and indirect costs and, in extreme cases, the loss of human lives. The use of Artificial Neural Network (ANN) models has been recently proposed in the literature for estimating the maximum scour depth around bridge piers: this study aims at further investigating the potentiality of the ANN approach and, in particular, at analysing the influence of the experimental setting (laboratory or field data) and of the sediment transport mode (clear water or live bed) on the prediction performances. A large database of both field and laboratory observations has been collected from the literature for predicting the maximum local scour depth as a function of a parsimonious set of variables characterizing the flow, the sediments and the pier. Neural networks with an increasing degree of specialization have been implemented – using different subsets of the calibration data in the training phase – and validated over an external validation dataset. The results confirm that the ANN scour depths' predictions outperform the estimates obtained by empirical formulae conventionally used in the literature and in the current engineering practice, and demonstrate the importance of taking into account the differences in the type of available data – laboratory or field data – and the sediment transport mode – clear water or live bed conditions

ALCUNE CONSIDERAZIONI DELLA SOCIETÀ IDROLOGICA ITALIANA SULLA GRAVE SICCITÀ DELL’ESTATE 2022

La siccità che ha colpito il nostro Paese fin dall’inizio del 2022, ha posto all’attenzione della popolazione, at- traverso i media, un tema che i gestori delle risorse idriche, i tecnici e i ricercatori hanno ben presente, ma che non aveva ancora suscitato adeguato interesse nel dibattito politico. L’articolo del Ministro della Transizione Ecologica, Roberto Cingolani, pubblicato sul Corriere della Sera lo scorso 11 luglio, è un utile stimolo, per amministratori e politici, ad affrontare il tema della scarsità di risorse idriche e delle misure necessarie per mi- tigare l’impatto dei fenomeni siccitosi

Large-sample hydrology – a few camels or a whole caravan?

Large-sample datasets containing hydrometeorological time series and catchment attributes for hundreds of catchments in a country, many of them known as “CAMELS” (Catchment Attributes and MEteorology for Large-sample Studies), have revolutionized hydrological modelling and have enabled comparative analyses. The Caravan dataset is a compilation of several (CAMELS and other) large-sample datasets with uniform attribute names and data structures. This simplifies large-sample hydrology across regions, continents, or the globe. However, the use of the Caravan dataset instead of the original CAMELS or other large-sample datasets may affect model results and the conclusions derived thereof. For the Caravan dataset, the meteorological forcing data are based on ERA5-Land reanalysis data. Here, we describe the differences between the original precipitation, temperature, and potential evapotranspiration (Epot) data for 1252 catchments in the CAMELS-US, CAMELS-BR, and CAMELS-GB datasets and the forcing data for these catchments in the Caravan dataset. The Epot in the Caravan dataset is unrealistically high for many catchments, but there are, unsurprisingly, also considerable differences in the precipitation data. We show that the use of the forcing data from the Caravan dataset impairs hydrological model calibration for the vast majority of catchments; i.e. there is a drop in the calibration performance when using the forcing data from the Caravan dataset compared to the original CAMELS datasets. This drop is mainly due to the differences in the precipitation data. Therefore, we suggest extending the Caravan dataset with the forcing data included in the original CAMELS datasets wherever possible so that users can choose which forcing data they want to use or at least indicating clearly that the forcing data in Caravan come with a data quality loss and that using the original datasets is recommended. Moreover, we suggest not using the Epot data (and derived catchment attributes, such as the aridity index) from the Caravan dataset and instead recommend that these should be replaced with (or based on) alternative Epot estimates

Water–tourism nexus research in the Mediterranean in the past two decades: a systematic literature review

The water–tourism nexus requires better knowledge, management and governance to address environmental and societal challenges. This review takes stock of the approaches used to address this nexus in the Mediterranean from 2000 to 2020. Bibliometric and exploratory content analysis targeted tourism impacts on water supply, determinants of water consumption, and water-saving mechanisms and technologies. A fundamental insight is that the literature remains rather water centric and technical, paying little attention to behavioural change and stakeholder action. Promising avenues to reinforce sustainable water use include transdisciplinary approaches and integrated tools such as hydrosocial cycle analysis, concept mapping and agent-based modelling.The authors thank the European Commission, the Dutch Research Council, the State Investigation Agency (Spanish Ministry of Economic Affairs and Digital Transformation) and the Italian Ministry of Education, Universities and Research for funding in the frame of the collaborative international consortium (SIMTWIST) financed under the 2018 Joint Call of the WaterWorks 2017 ERA-NET Cofund. This ERA-NET is an integral part of the activities developed by the Water JPI

Structural and molecular rationale for the diversification of resistance mediated by the Antibiotic_NAT family

The environmental microbiome harbors a vast repertoire of antibiotic resistance genes (ARGs) which can serve as evolutionary predecessors for ARGs found in pathogenic bacteria, or can be directly mobilized to pathogens in the presence of selection pressures. Thus, ARGs from benign environmental bacteria are an important resource for understanding clinically relevant resistance. Here, we conduct a comprehensive functional analysis of the Antibiotic_NAT family of aminoglycoside acetyltransferases. We determined a pan-family antibiogram of 21 Antibiotic_NAT enzymes, including 8 derived from clinical isolates and 13 from environmental metagenomic samples. We find that environment-derived representatives confer high-level, broad-spectrum resistance, including against the atypical aminoglycoside apramycin, and that a metagenome-derived gene likely is ancestral to an aac(3) gene found in clinical isolates. Through crystallographic analysis, we rationalize the molecular basis for diversification of substrate specificity across the family. This work provides critical data on the molecular mechanism underpinning resistance to established and emergent aminoglycoside antibiotics and broadens our understanding of ARGs in the environment

Twenty-Three Unsolved Problems in Hydrology (UPH) – a Community Perspective

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come

Review of global change pressures on Urban Water Cycle Systems. Assessment of TRUST Pilots

The design of appropriate tools to deal with future stresses requires an understanding of the potential pressures, either opportunities or threats. This report identifies and describes different pressures of critical importance for the water sector, taking into account that global trends often take diverse forms and have dissimilar impacts on a local scale. Chapter 1 introduces the UWCS components and the sustainability approach considered in this context. In Chapter 2 the different pressures affecting UWCS are framed according to the sustainability dimensions: environmental, social and economic. A general description of relevant pressures is presented in terms of context situation, geographic dependency and expected tendencies for the future. Chapter 3 identifies possible future trends on UWCS according to those pressures. Their consideration will allow many countries to undergo considerable changes and to define strategies to solve impending problems and exploit emerging opportunities. Based on the identified trends for the water sector, Chapter 4 presents the prediction of major global change pressures and its impacts on Pilots of TRUST. The two annexes of this report present the principal climatic drivers, in terms of the future projection of weather variables (precipitation and temperature) in the areas of the TRUST pilot citiesRamôa, AR.; Toth, E.; Proença De Oliveira, R.; Di Frederico, V.; Montanari, A.; Monteiro, AJ. (2015). Review of global change pressures on Urban Water Cycle Systems. Assessment of TRUST Pilots. http://hdl.handle.net/10251/5364