Spatially-smooth regionalization of flow duration curves in non-pristine basins

The flow duration curve (FDC) is a fundamental signature of the hydrological cycle to support water management strategies. Despite many studies on this topic, its estimation in ungauged basins is still a relevant issue as the FDC is controlled by different types of processes at different time-space scales, thus resulting quite sensitive to the specific case study. In this work, a regional spatially-smooth procedure to evaluate the annual FDC in ungauged basins is proposed, based on the estimation of the L-moments (mean, L-CV and L-skewness) through regression models valid for the whole case study area. In this approach, homogeneous regions are no longer required and the L-moments are allowed to continuously vary along the river network, thus providing a final FDC smoothly evolving for different locations on the river. Regressions are based on a set of topographic, climatic, land use and vegetation descriptors at the basin scale. Moreover, the model ensures that the mean annual runoff is preserved at the river confluences, i.e. the sum of annual flows of the upstream reaches is equal to the predicted annual downstream flow. The proposed model is adapted to incorporate different “sub-models” to account for local information within the regional framework, where man-induced alterations are known, as common in non-pristine catchments. In particular, we propose a module to consider the impact of existing/designed water withdrawals on the L-moments of the FDC. The procedure has been applied to a dataset of daily observation of about 120 gauged basins on the upper Po river basin in North-Western Italy

Reconstruction and Analysis of the Po River Inundation of 1951

Flood inundation models have become essential tools in flood risk management, being used also in the analysis of historical flood events, which is often needed for a reliable assessment of the potential flood hazard. This study aims at reconstructing the 1951 inundation of the Polesine Region, Italy. The 1951 flooding was a mayor natural catastrophe that caused a large inundated area (1080 km2) and produced devastating social consequences. The reconstruction of the 1951 hydraulic conditions is based on partial knowledge of discharges and water stages at the Pontelagoscuro gauging station (downstream of the 1951 levee breach) using extrapolation of the rating curves beyond the measurement range. This is, even today, something open to uncertainty. We applied a decoupled hybrid approach to the hydraulic modeling: a 1D model is used to simulate the flow into the river and to compute the flow through the levee breach; this result is then adopted as the inflow condition for a 2D model application on the inundated area. A good agreement between the patterns of the observed and reconstructed inundation areas was found, and the timing of the inundation was also found to be close to the information derived from the historical chronicles. The results of the flood inundation modelling exercise provide two practical insight: (i) obstacles in the floodplains increased the flooded area by 40% and prolonged the time to reach the sea from 5 to 15 days, (ii) the peak discharge of the event was overestimated by up to 20

Practical aspects related to the measurement of the diffuse field absorption coefficient in scaled reverberation rooms

The scaled reverberation room has proven to be an excellent tool for acoustic consultants and professionals alike to carry out comparison tests between acoustic materials and 3D systems or structures. The suitability of a scaled reverberation room is currently under investigation for the evaluation of the frequency-dependent sound absorption. At present, no standard is available on the methods that could be used to derive acoustic absorption coefficients from scaled measurements. In this work practical aspects of ISO 354 have been investigated within a 1:5 scaled reverberation room: a balance has been sought between reducing sample size, to reduce the manufacturing costs of materials, and finding the appropriate sample area, thickness, orientation and edges treatment, to obtain reliable values at mid and high frequencies. Four different materials have been tested. The paper discusses some of the findings of the measurements conducted on the same materials in a full-scale reverberation room according to ISO 354, in a 1:5 scaled reverberation room and in an impedance tube according to ISO 10534-2. The absorption coefficients data collected have been effective in proving that small reverberation room tests can provide compatible results compared to standard ones in 400-5000 Hz frequency range

Mosquito-Borne Diseases and ‘One Health’: The Northwestern Italian Experience

In Italy, the surveillance of Mosquito-Borne Diseases (MBDs) is regulated by two national preparedness plans: (1) for West Nile and Usutu viruses, integrating human and veterinary surveillance in order to early detect viruses circulation and to quickly apply control measures aimed at reducing the risk of transmission through blood and blood components and (2) for Arbovirosis transmitted by Aedes mosquitoes, mainly Chikungunya, Dengue and Zika viruses, based on surveillance of both imported and autochthonous human cases. This chapter reports the results of the application of these National Plans in Northwestern Italy and their impact for human health. In detail, we present the coordinated activities enforced in Piemonte and Liguria Regions, as a good example of the ‘One Health approach’ to control MBDs and prevent human transmission

Water Resources and Flood Hazard Assessment with Consideration of Anthropic Effects

Studies on water resources are rarely developed in basins where anthropic impact is negligible; therefore, the flow values are seldom ''natural'' and are often significantly affected by the interference of human works. These alterations of the natural discharges can be due to the presence, along the river network, of interfering hydraulic structures. Interactions between these infrastructures and the natural streamflow are certainly in need of further attention. Two main issues have been studied here in detail: i) the impact on water availability and the variability caused by water abstractions and ii) the flood attenuation effect induced by existing reservoirs, that produces flood hazard mitigation downstream. When working in a regional analysis framework, input data and results should represent the natural conditions. Hence, the alterations due to hydraulics structures embedded into the river network should be removed or introduced carefully. For instance, regional estimates of flood peak discharges do not consider the flood attenuation operated by the existing reservoirs. Nevertheless dams have a significant impact, especially in the nearest areas downstream, that should be accounted for. For the Piemonte and Valle d'Aosta Regions, this flood peak attenuation effect has been studied in detail to provide a correct starting point for further flood hazard studies. On the other hand, to assess the impact of water abstractions on daily discharge data, basic indices of alterations have been defined and an innovative correction model to reconstruct the natural streamflow statistics has been proposed. Non-impacted discharge characteristics are needed to provide a correct regional estimate of water resources availability and, consequently, of the gross hydropower potential. For water use planning purposes or to define the residual hydropower potential, the correction model proposed can also be used backward, adding anthropic effects to non-impacted values of discharge. The relevance of the proposed approach and methods in regional analysis of extreme and average flows is something that can be better recognized only with the effort of systematically characterizing the infrastructures that interfere with the natural hydrology along the river network. The applications made in this work were made possible by a cooperative effort addressed to the realization of a comprehensive Hydrological and Infrastructures Information System for the Regione Piemonte, that constitutes an important laboratory for hydrological simulations in a real world of heavily altered natural processe

Vibrazioni - Cap. G

Studi sull’impatto ambiental

Clima e cambiamenti climatici - Cap. I

Studi sull’impatto ambiental