Bisagno. Il fiume nascosto.

«Bisagno è per me storia, gioia, dolore, resistenza». Così Don Gallo affrontò il manoscritto di questo saggio, senza poterne finire la chiosa. Narra la storia idraulica, civile e politica del Bisagno, il fiume che i genovesi hanno condannato all'oblio. Fiorentini e romani, parigini e londinesi sono fieri della nobiltà dei loro grandi fiumi. Genova invece si vergogna del suo misero torrente, tanto da nasconderlo, dalla foce ai monti. Iniziò in sordina, seppellendo alcuni affluenti tra l'Ottocento e l'inizio del Novecento; edificò la foce negli anni trenta, quando era diventata Superba; e, verso la fine degli anni ottanta, fabbricò alla chetichella le piastre davanti alla stadio, a vera gloria del calcio nazionale. Continuando a incanalarlo nel cemento, coprirne gli affluenti e mandarne in malora i terrazzi, con una progressione pervicace quanto ostinata. Pagando un prezzo altissimo in vittime per le ricorrenti alluvioni: l'unica ribellione del fiume alla sua condanna. Dimenticando rapidamente i suoi morti, sempre innocenti. Spesso inconsapevoli. Attraverso la voce di coloro che dialogarono con il Bisagno, dal Giustiniani al Magnasco, da Lord Byron a Fabrizio De André, Edith Wharton e Mary Shelley, Genova si specchia nel suo fiume inquieto, mentre parallela scorre la malinconica vicenda del malgoverno dell'acqua e della difesa del suolo in Italia. Un testo scientifico rigoroso, ricco di argomenti tecnici; e, nello stesso tempo, un percorso emotivo e sentimentale di cronache personali e collettive. La storia di una città e di un paese che non hanno saputo convivere finora con la propria fragilità idrogeologica

Evaluation of future hydrological cycle under climate change scenarios in a mesoscale Alpine watershed of Italy

Abstract. We investigate future (2045–2054) hydrological cycle of the snow fed Oglio (≈1800 km2) Alpine watershed in Northern Italy. A Stochastic Space Random Cascade (SSRC) approach is used to downscale future precipitation from three general circulation models, GCMs (PCM, CCSM3, and HadCM3) available within the IPCC's data base and chosen for this purpose based upon previous studies. We then downscale temperature output from the GCMs to obtain temperature fields for the area. We also consider a projected scenario based upon trends locally observed in former studies, LOC scenario. Then, we feed the downscaled fields to a minimal hydrological model to build future hydrological scenarios. We provide projected flow duration curves and selected flow descriptors, giving indication of expected modified (against control run for 1990–1999) regime of low flows and droughts and flood hazard, and thus evaluate modified peak floods regime through indexed flood. We then assess the degree of uncertainty, or spread, of the projected water resources scenarios by feeding the hydrological model with ensembles projections consistent with our deterministic (GCMs + LOC) scenarios, and we evaluate the significance of the projected flow variables against those observed in the control run. The climate scenarios from the adopted GCMs differ greatly from one another with respect to projected precipitation amount and temperature regimes, and so do the projected hydrological scenarios. A relatively good agreement is found upon prospective shrinkage and shorter duration of the seasonal snow cover due to increased temperature patterns, and upon prospective increase of hydrological losses, i.e. evapotranspiration, for the same reason. However, precipitation patterns are less consistent, because HadCM3 and PCM models project noticeably increased precipitation for 2045–2054, whereas CCSM3 provides decreased precipitation patterns therein. The LOC scenario instead displays unchanged precipitation. The ensemble simulations indicate that several projected flow variables under the considered scenarios are significantly different from their control run counterparts, and also that snow cover seems to significantly decrease in duration and depth. The proposed hydrological scenarios eventually provide a what-if analysis, giving a broad view of the possible expected impacts of climate change within the Italian Alps, necessary to trigger the discussion about future adaptation strategies

Sulphated Polysaccharides and the Differentiation of the Cellular Slime Mould Dictyostelium Discoideum

SUMMARYCell surface and endocellular polysaccharides of growing and differentiated Dictyostelium discoideum have been isolated and characterized with electrophoretic and chromatographyc procedures.The mould exhibit a very eterogeneous family of sulphated polysaccharides which are externalized during the differentiation.The possible role of cell surface polysaccharides in the differentiation process is discussed

Green roofs effects on the urban water cycle components

AbstractGreen roofs are emerging as an increasingly popular Sustainable Urban Drainage Systems (SUDS) technique for urban stormwater management. Indeed, they allow a significant reduction of peak flows and runoff volumes collected by drainage system, with consequent reduction of flooding events and pollution masses discharges by CSO. To estimate the imperviousness of a green roof and to evaluate its hydrological impact within an urban watershed, a bucket model was developed to simulate a rainfall-runoff relationship for a single green roof. The objective is modeling hydrological fluxes in relation to climate forcing, basic technology components and geometric characteristics of green roof systems

Le théâtre antique d’Orange : un immense chantier au service de la connaissance

International audienc

Future Hydrological Regimes in the Upper Indus Basin: A Case Study from a High-Altitude Glacierized Catchment

The mountain regions of the Hindu Kush, Karakoram, and Himalayas (HKH) are considered Earth’s “third pole,” and water from there plays an essential role for downstream populations. The dynamics of glaciers in Karakoram are complex, and in recent decades the area has experienced unchanged ice cover, despite rapid decline elsewhere in the world (the Karakoram anomaly). Assessment of future water resources and hydrological variability under climate change in this area is greatly needed, but the hydrology of these high-altitude catchments is still poorly studied and little understood. This study focuses on a particular watershed, the Shigar River with the control section at Shigar (about 7000 km2), nested within the upper Indus basin and fed by seasonal melt from two major glaciers (Baltoro and Biafo). Hydrological, meteorological, and glaciological data gathered during 3 years of field campaigns (2011–13) are used to set up a hydrological model, providing a depiction of instream flows, snowmelt, and ice cover thickness. The model is used to assess changes of the hydrological cycle until 2100, via climate projections provided by three state-of-the-art global climate models used in the recent IPCC Fifth Assessment Report under the representative concentration pathway (RCP) emission scenarios RCP2.6, RCP4.5, and RCP8.5. Under all RCPs, future flows are predicted to increase until midcentury and then to decrease, but remaining mostly higher than control run values. Snowmelt is projected to occur earlier, while the ice melt component is expected to increase, with ice thinning considerably and even disappearing below 4000 m MSL until 2100

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 on-line 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 focussed on 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