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This article analyses the assessment of economic damages in urbanised flooded areas by testing the use of reimbursement data to obtain damage curves. Data coming from field observation of the 2000 flood in Piedmont, Italy, are used and the influence of local features and topography, as well as urban patterns are studied. Our starting point is the assessment of individual flooded elements, whose damages result from slightly more than 7000 refund claims. Damage functions estimation is carried out by using water depth and flow velocities obtained by 2D inundation model. Results show the relationship of damage versus water depth and versus flow velocity are strongly nonlinear and urban patterns playing a major role in explaining the amount of damage under given conditions. Moreover, results provide useful information for future ex ante estimation of potential flood damages and rewarding risk reductions and management actions. [ABSTRACT FROM AUTHOR] more...

As most of the rural areas in Mediterranean Region, the Celone river basin (Apulia, Italy) is characterized by diffuse pollution from agriculture. Nutrient export from terrestrial ecosystem to the river is controlled by hydrological processes and nutrient input from point and non-point sources. In the present paper, anthropogenic nitrogen input and the riverine export of nitrate-N (N-NO) were quantified through several survey campaigns, continuous measures of streamflow and discrete determinations of concentrations. A different frequency for water sampling was used, respectively, during floods and during normal- or low-flow state. Nitrate-N concentrations in surface waters were found to vary considerably across the seasons. The riverine N-NO export was estimated to be about 14 kg N ha year. Major N inputs derived from fertilizers and animal manure correspond to 68.2 and 24 kg N ha year, respectively. Nitrate-N fluxes in stream during flood events (21 days) accounted for about 63% of the annual loading. This study clearly demonstrates the importance of flood event contributions to the annual nutrient loading delivered to the reservoir and that more efficient fertilizers and management practices are needed to reduce N input. [ABSTRACT FROM AUTHOR] more...

Severe wildfires are often followed by significant increase in runoff and erosion, due to vegetation damages and changes in physical and chemical soil properties. Peak flows and sediment yields can increase up to two orders of magnitude becoming dangerous for human lives and ecosystem, especially in the wildland-urban interface. Watershed post fire rehabilitation measures are usually used to mitigate the effects of fire on runoff and erosion, by protecting soil from splash and shear stress detachment and enhancing its infiltration capacity. Modeling post fire erosion and erosion mitigation strategies can be useful in selecting the effectiveness of rehabilitation method. In this paper a distributed model based on Revised Universal Soil Loss Equation (RUSLE), properly parameterized for a Mediterranean basin located in Sardinia, is used to determine soil losses for six different scenarios describing both natural and post-fire basin condition, the last accounting also for the single and combined effect of different erosion mitigation measures. Fire effect on vegetation and soil properties have been mimed by changing soil drainage capacity and organic matter content, and RUSLE factors related to soil cover and protection measures. Model results show for the analyzed rehabilitation treatments their effect in reducing the amount of soil losses with the peculiar characteristics of the spatial distribution of such changes. [ABSTRACT FROM AUTHOR] more...

In this paper, a proof of concept experiment is conducted to assess the feasibility of tracing overland flow on an experimental hillslope plot via a novel fluorescent particle tracer. Experiments are performed by using beads of diameters ranging from 75 to 1180 µm. Particles are sensed through an experimental apparatus comprising a light source and a video acquisition unit. Runoff on the experimental plot is artificially simulated by using a custom-built rainfall system. Particle transits are detected through supervised methodologies requiring the presence of operators and unsupervised procedures based on image analysis techniques. Average flow velocity estimations are executed based on travel time measurements of the particles as they are dragged by the overland flow on the hillslope. Velocities are compared to flow measurements obtained using rhodamine dye. Experimental findings demonstrate the potential of the methodology for understanding overland flow dynamics in complex natural settings. In addition, insights on the optimization of particle size are presented based on the visibility of the beads and their accuracy in flow tracing. [ABSTRACT FROM AUTHOR] more...

In this paper, a proof of concept experiment is conducted to assess the feasibility of tracing overland flow on a semi-natural hillslope plot via a novel fluorescent particle tracer. Runoff on the experimental plot is artificially simulated by using a custom-built rainfall system. Experiments are performed by using beads of diameters ranging from 75 to 1180 µm that are sensed through an experimental apparatus comprising a light source and a video acquisition unit. Particles' transit is detected through an unsupervised methodology based on image analysis techniques and compared to results from supervised visual inspection. Average flow velocity estimations are obtained from travel time measurements of the particles as they are dragged by the overland flow on the hillslope. Velocities are compared to flow measurements obtained using rhodamine dye. Experimental findings demonstrate the potential of the methodology for understanding overland flow dynamics in complex natural settings. In addition, considerations for optimizing the particle size are presented based on the visibility of the beads and their accuracy in flow tracing. [ABSTRACT FROM AUTHOR] more...

A flume experiment is carried out to explore jamming of Large Woody Debris (LWD) in streams with complex morphology, occurring in mountain streams with in channel boulders or vegetation, in braided rivers or in floodplains during flood events. Non rooted, defoliated LWD is modeled using wood dowels and obstacles to motion are represented by vertical wood rods. Congested transport of LWD is simulated by insertion of a number (100) of dowels. The final position of the dowels is mapped and the observed jams are classified according to their size and position. The key member of each jam is identified and its trapping mechanism evaluated, either by leaning against a single obstacle or by bridging two obstacles. To mimic uncongested transport, the experiment is repeated for single pieces of wood, with subsequent removal. Longer dowels and shallower water result in shorter traveled distance. Wood pieces travel farther when congested transport is observed. The traveled distance of the wood pieces can be modeled using a Gamma distribution, for both congested and uncongested transport. Jams instead display Uniform traveled distance. The number of pieces displays an Exponential distribution. The degree of uniformity in space of jams and wood pieces is evaluated using a neighbor K statistic. Wood pieces show considerable clustering, while jams show sparse distribution. Eventually, the relationship between jams magnitude and position is explored, showing negative correlation. Model application is then discussed and some conclusions and future developments are outlined. [ABSTRACT FROM AUTHOR] more...