Evaluation of the hydro-meteorological chain in Piemonte Region, north western Italy - analysis of two HYDROPTIMET test cases

International audienceThe HYDROPTIMET Project, Interreg IIIB EU program, is developed in the framework of the prediction and prevention of natural hazards related to severe hydro-meteorological events and aims to the optimisation of Hydro-Meteorological warning systems by the experimentation of new tools (such as numerical models) to be used operationally for risk assessment. The object of the research are the Mesoscale weather phenomena and the response of watersheds with size ranging from 102 to 103 km2. Non-hydrostatic meteorological models are used to catch such phenomena at a regional level focusing on the Quantitative Precipitation Forecast (QPF). Furthermore hydrological Quantitative Discharge Forecast (QDF) are performed by the simulation of run-off generation and flood propagation in the main rivers of the interested territory. In this way observed data and QPF are used, in a real-time configuration, for one-way forcing of the hydrological model that works operationally connected to the Piemonte Region Alert System. The main hydro-meteorological events that interested Piemonte Region in the last years are studied, these are the HYDROPTIMET selected test cases of 14-18 November 2002 and 23-26 November 2002. The results obtained in terms of QPF and QDF offer a sound basis to evaluate the sensitivity of the whole hydro-meteorological chain to the uncertainties in the numerical simulations. Different configurations of non-hydrostatic meteorological models are also analysed

Variación espacio-temporal de Chironomidae (Diptera) bentónicos y derivantes en un arroyo serrano en Córdoba, Argentina

Chironomidae es una de las familias más abundantes y diversas en los ecosistemas de agua dulce, sin embargo su complejidad sistemática ha sido motivo de su escaso desarrollo en muchos estudios limnológicos. El objetivo de este estudio fue analizar los ensambles de Chironomidae bentónicos y derivantes de un arroyo serrano de la región central de Argentina evaluando abundancia, diversidad y composición de especies en diferentes hábitats fluviales y distintas estaciones del año. Se tomaron muestras cuantitativas de bentos y deriva en el arroyo Achiras (Córdoba, Argentina) en hábitats de rabión y corredera, y se registraron variables ambientales en las cuatro estaciones del año, entre 2007 y 2008. Se registró un total de 25 taxones pertenecientes a cuatro subfamilias. Los quironómidos bentónicos constituyeron el 19% de la comunidad de macroinvertebrados, mientras que en deriva representaron el 33%. En el bentos dominó Thienemannimyia sp. y en la deriva, Corynoneura sp. De acuerdo con los resultados de ANOVAs de dos vías, los mayores valores de riqueza taxonómica y densidad bentónica se registraron en el periodo de aguas bajas (otoño e invierno) y la diversidad de quirónomidos bentónicos fue mayor en rabión. Por el contrario, para el ensamble de derivantes sólo la equitatividad fue diferente entre hábitats y entre estaciones. El análisis TWINSPAN mostró una separación espacio-temporal de las muestras de bentos, mientras que las muestras de deriva se segregaron sólo temporalmente lo que sugiere que el transporte aguas abajo de los invertebrados homogeniza la variación espacial observada en el bentos. La densidad de bentos y deriva varió de manera similar a través de las estaciones del año y el coeficiente de Jaccard presentó un alto índice de similitud entre bentos y deriva (86%). Este trabajo posibilitó conocer la dinámica temporal y espacial de los quironómidos bentónicos y derivantes en un arroyo serrano. La ampliación del conocimiento taxonómico, biológico y ecológico de Chironomidae posibilitará adecuar e implementar estrategias de manejo y conservación de los ecosistemas lóticos en la región central de Argentina.Spatio-temporal variation of benthic and drifting Chironomidae (Diptera) in a mountain stream in Córdoba, Argentina. Chironomidae is one of the most abundant and diverse families in freshwater ecosystems, however its highly complex systematic has led to its scarce development in many limnological studies. The aim of this study was to analyze benthic and drifting Chironomidae assemblages in a mountain stream of central Argentina assessing abundance, diversity and taxa composition in different fluvial habitats and seasons. Quantitative benthic and drift samples were taken in the Achiras stream (Córdoba, Argentina) in rifles and runs, and environmental variables were measured in each season between 2007 and 2008. A total of 25 taxa were registered belonging to four subfamilies. Benthic chironomids represented 19% of the macroinvertebrate community, whereas they constituted 33% in drift. Thienemannimyia sp. dominated in benthos and Corynoneura sp. in drift. According to the two-way ANOVAs results, the highest taxonomic richness and benthic density were registered during the low flow period (autumn and winter) and the highest benthic diversity was found in riffles. On the contrary, in the drifting assemblage only evenness was different between habitats and among seasons. TWINSPAN analysis showed a spatio-temporal segregation of benthic samples, whereas drift samples were separated only temporally suggesting that the dislodgment of invertebrates downstream homogenize the spatial variation observed in benthos. Benthic and drift density varied in a similar manner through seasons and Jaccard coefficient showed a high similarity index between benthos and drift (86%). This study allowed knowing the spatio-temporal dynamic of benthic and drifting Chironomidae in a mountain stream. The increase of knowledge in relation to taxonomy, biology and ecology of Chironomidae will allow to adequate and apply management and conservation strategies of lotic ecosystems in the central region of Argentina.Fil: Zanotto Arpellino, Juan Pablo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; ArgentinaFil: Principe, Romina Elizabeth. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Oberto, Ana M.. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; ArgentinaFil: Gualdoni, Cristina M.. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; Argentin

Evaluation of Fresh Groundwater Lens Volume and Its Possible Use in Nauru Island

A proper management of fresh groundwater lenses in small islands is required in order to avoid or at least limit uncontrolled saltwater intrusion and guarantee the availability of the resource even during drought occurrences. An accurate estimation of the freshwater volume stored in the subsoil is a key step in the water management decision process. This study focused on understanding the hydrogeological system behaviour and on assessing the sustainable use of the groundwater resource in Nauru Atoll Island (Pacific Ocean). A first phase, concerning the hydrogeological characterization of the island, highlighted the occurrence of few drought-resilient freshwater lenses along the seashore. The second part of the study focused on the characterization of a freshwater lens found in the northern coastal area and identified such area as the most suitable for the development of groundwater infrastructures for water withdrawal. The characterization activities allowed quantifying the freshwater lens thickness and volume in order to assess the capability to satisfy the population water demand. A geo-electrical tomography survey was carried out, and a 3D density-dependent numerical model was implemented in SEAWAT. The model results demonstrated that in small islands freshwater can unexpectedly accumulate underground right along the seashore and not in the centre of the island as is commonly believed. Furthermore, the model can constitute a useful tool to manage the groundwater resources and would allow the design of sustainable groundwater exploitation systems, avoiding saltwater intrusion worsening

Hierarchical progressive surveys. Multi-resolution HEALPix data structures for astronomical images, catalogues, and 3-dimensional data cubes

Scientific exploitation of the ever increasing volumes of astronomical data requires efficient and practical methods for data access, visualisation, and analysis. Hierarchical sky tessellation techniques enable a multi-resolution approach to organising data on angular scales from the full sky down to the individual image pixels. Aims. We aim to show that the Hierarchical progressive survey (HiPS) scheme for describing astronomical images, source catalogues, and three-dimensional data cubes is a practical solution to managing large volumes of heterogeneous data and that it enables a new level of scientific interoperability across large collections of data of these different data types. Methods. HiPS uses the HEALPix tessellation of the sphere to define a hierarchical tile and pixel structure to describe and organise astronomical data. HiPS is designed to conserve the scientific properties of the data alongside both visualisation considerations and emphasis on the ease of implementation. We describe the development of HiPS to manage a large number of diverse image surveys, as well as the extension of hierarchical image systems to cube and catalogue data. We demonstrate the interoperability of HiPS and Multi-Order Coverage (MOC) maps and highlight the HiPS mechanism to provide links to the original data. Results. Hierarchical progressive surveys have been generated by various data centres and groups for ~200 data collections including many wide area sky surveys, and archives of pointed observations. These can be accessed and visualised in Aladin, Aladin Lite, and other applications. HiPS provides a basis for further innovations in the use of hierarchical data structures to facilitate the description and statistical analysis of large astronomical data sets.Comment: 21 pages, 6 figures. Accepted for publication in Astronomy & Astrophysic

Calidad ambiental en un río urbano de llanura

Environmental quality in a lowland urban river. Ecological integrity or health of a river is evaluated not only by the physical chemical and biological characteristics in the fluvial channel but also by the state of the riparian systems. Attributes of the benthic communities and the riparian areas are integrated to the chemical macroindicators. The objective of this work is to evaluate the environmental quality of the Chocancharava river plain reach in the urban sector and surroundings of Río Cuarto city. Three study sites were selected: in pre-urban, urban and post-urban reaches. Sampling and field data collections were made in two different hydrological periods: winter and summer. Physical and chemical data were registered and benthos samples were taken from transects across different habitats with a Hess sampler. Multimetric indices from structural attributes such as richness, composition and tolerance/intolerance were calculated. The riparian forest quality (RFQ) was evaluated. The obtained score enabled to describe the ecological status. The physical and chemical indicators showed good water quality and the multimetric indices determined a low impaired biological quality. The application of RFQ index showed an extreme degradation of the riparian system quality. The combination of the indices determined a bad ecological status. The results of this study contribute to corroborate that the Chocancharava river, in the urban sector and its surroundings, presents environmental deterioration, and that remediation and improvement measures are necessary.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Calidad ambiental en un río urbano de llanura

Environmental quality in a lowland urban river. Ecological integrity or health of a river is evaluated not only by the physical chemical and biological characteristics in the fluvial channel but also by the state of the riparian systems. Attributes of the benthic communities and the riparian areas are integrated to the chemical macroindicators. The objective of this work is to evaluate the environmental quality of the Chocancharava river plain reach in the urban sector and surroundings of Río Cuarto city. Three study sites were selected: in pre-urban, urban and post-urban reaches. Sampling and field data collections were made in two different hydrological periods: winter and summer. Physical and chemical data were registered and benthos samples were taken from transects across different habitats with a Hess sampler. Multimetric indices from structural attributes such as richness, composition and tolerance/intolerance were calculated. The riparian forest quality (RFQ) was evaluated. The obtained score enabled to describe the ecological status. The physical and chemical indicators showed good water quality and the multimetric indices determined a low impaired biological quality. The application of RFQ index showed an extreme degradation of the riparian system quality. The combination of the indices determined a bad ecological status. The results of this study contribute to corroborate that the Chocancharava river, in the urban sector and its surroundings, presents environmental deterioration, and that remediation and improvement measures are necessary.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA