Indagini sul bacino imbrifero

No abstract availabl

Idrologia e clima. Apporti quantitativi a lago: piogge, portate e coefficiente di deflusso

Not availableI dati di precipitazione, per l\u27anno 2013, sono stati raccolti, come di consueto, dalle stazioni pluviometriche dell?Istituto per lo Studio degli Ecosistemi (CNR-ISE), del Servizio Meteorologico Svizzero, dell?Ufficio dei Corsi d?Acqua, Dipartimento del Territorio del Canton Ticino, dell\u27ENEL, dell?Area Previsione e Monitoraggio Ambientale dell?Arpa Piemonte, delle Officine Idroelettriche della Blenio-Maggia, della Societ? Idroelettriche Riunite, dell?Istituto Geofisico Prealpino e del Consorzio del Ticino. Nel 2013 si sono registrati, mediamente all?interno del bacino del Lago Maggiore, 1710 mm, valore in perfetta media pluriennale. I dati riguardanti i deflussi dei principali immissari e dell\u27emissario del Lago Maggiore, sono stati misurati nel 2013, attraverso le reti di rilevamento dell\u27Istituto per lo Studio degli Ecosistemi, dell?Area Previsione e Monitoraggio Ambientale dell?Arpa Piemonte, dell?Ufficio Federale dell?Ambiente di Berna (UFAM) e dei Consorzi del Bardello e del Ticino. L?andamento delle portate nel 2013 ? stato determinato dalla bassa piovosit? dei primi tre mesi dell?anno e dalle consistenti piogge di aprile e maggio che hanno portato la maggior parte dei corsi d?acqua a far registrare i massimi valori di portata proprio nel mese di maggio. La media delle portate annuali ? stata leggermente al di sotto dei valori di riferimento

Fluctuations of Lake Orta water levels: preliminary analyses

While the effects of past industrial pollution on the chemistry and biology of Lake Orta have been well documented, annual and seasonal fluctuations of lake levels have not yet been studied. Considering their potential impacts on both the ecosystem and on human safety, fluctuations in lake levels are an important aspect of limnological research. In the enormous catchment of Lake Maggiore, there are many rivers and lakes, and the amount of annual precipitation is both high and concentrated in spring and autumn. This has produced major flood events, most recently in November 2014. Flood events are also frequent on Lake Orta, occurring roughly triennially since 1917. The 1926, 1951, 1976 and 2014 floods were severe, with lake levels raised from 2.30 m to 3.46 m above the hydrometric zero. The most important event occurred in 1976, with a maximum level equal to 292.31 m asl and a return period of 147 years. In 2014 the lake level reached 291.89 m asl and its return period was 54 years. In this study, we defined trends and temporal fluctuations in Lake Orta water levels from 1917 to 2014, focusing on extremes. We report both annual maximum and seasonal variations of the lake water levels over this period. Both Mann-Kendall trend tests and simple linear regression were utilized to detect monotonic trends in annual and seasonal extremes, and logistic regression was used to detect trends in the number of flood events. Lake level decreased during winter and summer seasons, and a small but statistically non-significant positive trend was found in the number of flood events over the period. We provide estimations of return period for lake levels, a metric which could be used in planning lake flood protection measures

Indagini sul bacino imbrifero

Not availableIndagini sul bacino imbrifero del Lago Maggiore e sulle sue caratteristiche idrologiche: pluviometria e defluss

Model simulations of the ecological dynamics induced by climate and nutrient load changes for deep subalpine Lake Maggiore (Italy/Switzerland)

Climate warming affects lake ecosystems both through its direct effect on the phenology of species and through the alteration of the physical and chemical environments, which in turn affect community composition. In deep lakes, stratification enhancement and mixing reduction have already been observed, leading to hypolimnetic anoxia and to the rise of cyanophytes. The increase in stability depends on the rise of air temperature due to global emissions of greenhouse gases (GHG). Primary production could then either increase with rising epilimnetic temperature and buoyancy or decrease as fewer nutrients are upwelled from deep layers. The prevailing outcome, as well as the quantitative and temporal dynamics of all climate-induced modifications, depend on the specific lake characteristics. Individual analyses are then needed, one-dimensional coupled hydrodynamic-ecological numerical models being suitable tools for such predictions. Here, we simulated with GLM-AED2 (General Lake Model – Aquatic EcoDynamics) the 2020-2085 dynamics of the oligomictic and oligotrophic deep subalpine Lake Maggiore (Italy/Switzerland), according to the Swiss Climate Change Scenarios CH2011. Multiple realisations were performed for each scenario with random meteorological series obtained from the Vector-Autoregressive Weather Generator (VG), highlighting the uncertainties related to meteorology. Increase and decrease of nutrient loads were also tested. Results show that anoxia would occur in the hypolimnion regardless of nutrient input reduction, unless global GHG emissions were immediately reduced. Total phytoplankton biomass would be weakly affected by climate change, strongly depending on nutrient input, yet water warming would cause cyanophytes to compete with diatoms. Therefore, the fate of Lake Maggiore would be tied to both global and local environmental policies

Progetto pilota per lo studio multidisciplinare ed integrato su un sottobacino del Lago Maggiore

No abstract availableSu di un corso d\u27acqua transfrontaliero si sono effettuate analisi multidisciplinari miranti alla definizione della sua qualit? ecologica, seguendo i metodi idromorfologico e campionamento chimico e a macroinvertebrati previsti dalla Direttiva Quadro sulle Acque 2000/60. Si sono quindi valutati gli impatti irdomorfologici presenti con l\u27applicazione del metodo CARAVAGGIO, e si sono definiti gli habitat e la loro qualit? da un punto di vista chimico e attraverso il campionamento della fauna a macroinvertebrati secondo protocollo MacrOper. I risultati del progetto sono stati molto interessanti sia da un punto di vista della caratterizzazione di tutti gli impatti presenti (anche attraverso la catalogazione delle diverse infrastrutture presenti lungo tutto il corso d\u27acqua) e della scoperta zone a particolare valenza ecologica, sia per la definizione della qualit? ecologica globale del corso d\u27acqua

Extreme rainfall events: evaluation with different instruments and measurement reliability

With regard to extreme events, it is known that an intensity of about 1 mm/min already represents an extreme intensity. Under alpine conditions, a precipitation event with intensity about 3 mm/min has occurred. Therefore the rain gauges in this region have to be able to measure in this and even in higher intensity ranges. This study deals with basically automated Tipping Bucket Rain (TBR) gauge, and Bulk precipitation samplers, which allows to hold back more than 95% of the cumulative rainfall that are verified within the space of the week without losses during the extreme events and with a minimum evaporation loss. In the last 10 years analysed, for a total of 221 extreme events, in 110 extreme events the Bulk samplers have collected rainfall more than automated TBR. In 17 extreme events an underestimation more than 10% was evaluated. The objective was to single out the counting errors associated with TBR gauge, during extreme events, so as to help the understanding of the measured differences between instruments in the field. We want to prove if the automated precipitation gauge, is or not, a reliable and precise device of measurements precipitation with particular interest regarding heavy and extreme events

The hydromorphological state in mountain rivers subject to human impacts: a case study in the North-West of Italy

The aim of this paper is the evaluation of the hydromorphological conditions of mountain rivers subject to extensive human activities. The hydromorphological state of a river depends on a high number of natural and anthropogenic characteristics, such as the presence of weirs, dams, or any other human infrastructure close to the riverbanks. The research focused on the mountain streams in Lake Maggiore catchment, located in the Italian Alps. The analyses were carried out using the method CARAVAGGIO (Core Assessment of River hAbitat VAlue and hydromorpholoGIcal cOndition), which complies with the EC Water Framework Directive. An intensive campaign of field surveys was conducted and a great amount of data was collected to obtain specific synthesis indexes. In particular, the Habitat Quality Assessment (HQA) and the Habitat Modification Score (HMS) were used to determine the diversification of natural characteristics and the level of hydromorphological alteration in the study area. Furthermore, a Lentic-lotic River Descriptor (LRD) was used in support of the information obtained by HQA and HMS. This research shows that the worst hydromorphological conditions can be found in rivers characterised by a high level of human constructions and hydropower plants. Finally, regression analyses were implemented to search a relationship between HQA, HMS and some morphological parameters. LRD was correlated to some hydraulic parameters. The results of this research are characterised by a high stochasticity

Il mescolamento invernale del lago: dipendenza dalla meteorologia locale, dalle oscillazioni oceaniche nord-atlantiche (NAO) e dai cambiamenti climatici globali

Not availableCONTENUTI CALORICI, TEMPERATURA, OSSIGENO E STABILIT? TERMICA NELLE ACQUE DEL LAGO MAGGIORE NELL\u27ANNO 2014: Profondit? di mescolamento. ASPETTI DELLA DINAMICA DEL LAGO MAGGIORE CONDIZIONATI DAL CLIMA: Rapporto tra temperatura dell\u27aria e dell\u27acqua ; Contenuto di calore; Profondit? di mescolamento; Concentrazioni dell\u27 ossigeno ipolimnico; Stabilit? termica ; Rapporti tra gli indici M, NAOW e Trend

Permeable Pavements Efficiency Under Clogging and Pollutants Load Removal

Permeable pavement is used to reduce stormwater volume, peak flow and promote pollutant load removal (Scholz and Grabowiecki, 2007, Brunetti et al., 2016, Marchioni and Becciu, 2014). The volume reduction depends on the base depth, while peak flow and loads removal are dependent on the surface layer, that must present a hydraulic conductivity capable of significantly limiting runoff; while the pore structure acts as a filter retaining particulate matter (PM), deriving from erosive phenomena and anthropogenic activities. The infiltration capacity tends to decrease over time due to the PM accumulation. An adequate maintenance program guarantees that hydraulic conductivity remains above a threshold. The infiltration capacity is a function of the characteristics of the material used in the surface layer, normally permeable concrete (PC), porous asphalt (PA) or interlocking concrete blocks. For this research a series of a rainfall simulation tests were used to analyze the hydrological and load removal response of permeable pavement surface under clogging. Results confirm the permeable efficiency under clogging on stormwater runoff reduction and pollutants removal