An experimental apparatus, consisting of a tilting flume and a final horizontal plane, has been used to investigate the depositional features of debris materials collected from the Pulsano watershed (Southern-Italy). Experiments have been carried out to study the flow behaviour of mixtures at sediment concentrations 0.4≤Cv≤0.6 and maximum grain size of the particles 4mm≤d≤19mm. The flow behavior is described on the basis of the evolution of the front position in the channel and of the runout distance, lateral spreading and flow depth in the horizontal plane. An attempt is made to rate the experimental flows according to the classification of flow regimes based on threshold values of dimensionless Bagnold, Savage and Friction numbers. As a conclusion the experimental results highlight a threshold behaviour of debris-flow mixtures in the runout phase. This results from a particular combination of maximum grain diameters in play and a volumetric concentration limit. When approaching such combination the shape and the maximum length of the deposit change drastically if compared to those of the inertia-dominated regime.

The paper suggests a methodology, based on performance metrics, to select the optimal set of input and parameters to be used for the simulation of river flow discharges with a semi-distributed hydrologic model. The model is applied at daily scale in a semi-arid basin of Southern Italy (Carapelle river, basin area: 506 km2) for which rainfall and discharge series for the period 2006–2009 are available. A classification of inputs and parameters was made in two subsets: the former – spatially distributed – to be selected among different options, the latter – lumped – to be calibrated. Different data sources of (or methodologies to obtain) spatially distributed data have been explored for the first subset. In particular, the FAO Penman–Monteith, Hargreaves and Thornthwaite equations were tested for the evaluation of reference evapotranspiration that, in semi-arid areas, represents a key role in hydrological modeling. The availability of LAI maps from different remote sensing sources was exploited in order to enhance the characterization of the vegetation state and consequently of the spatio-temporal variation in actual evapotranspiration. Different type of pedotransfer functions were used to derive the soil hydraulic parameters of the area. For each configuration of the first subset of data, a manual calibration of the second subset of parameters was carried out. Both the manual calibration of the lumped parameters and the selection of the optimal distributed dataset were based on the calculation and the comparison of different performance metrics measuring the distance between observed and simulated discharge data series. Results not only show the best options for estimating reference evapotranspiration, crop coefficients, LAI values and hydraulic properties of soil, but also provide significant insights regarding the use of different performance metrics including traditional indexes such as RMSE, NSE, index of agreement, with the more recent Benchmark Efficiency (Schaefli and Gupta, 2007) and Kling–Gupta Efficiency (Gupta et al., 2009).

The AnnAGNPS model was used to estimate runoff, peak discharge and sediment yield at the event scale in the Carapelle watershed, a Mediterranean medium-size watershed (506 km2) located in Apulia, Southern Italy. The model was calibrated and validated using five years of runoff and sediment yield data measured at a monitoring station located at Ordona – Ponte dei Sauri Bridge. A total of 36 events was used to estimate the output of the model during the period 2007-2011, in comparison to the corresponding observations at the watershed outlet. The model performed well in predicting runoff, as was testified by the high values of the coefficients of efficiency and determination during the validation process. The peak flows predictions were satisfactory especially for the high flow events; the prediction capability of sediment yield was good, even if a slight over-estimation was observed.

The aim of the study is to investigate the influence of different land management options on the sediment load at the watershed scale. To reach this aim the Annualized AGricultural Non Point Source (AnnAGNPS) model was used in the Candelaro basin (2300 km2). The watershed is located in a semi-arid area of southern Italy (Puglia region) and is affected by extensive erosion processes on the hillslopes. The sediment transport simulations have been compared with 15 years (1970–1984) data coming from measures taken in two sub-watersheds (Vulgano and Salsola). Afterwards the model has been applied for a period of 24 years (1985–2008) to evaluate the effects of different land management options on the sediment yield: traditional best management practices (BMPs), environmentally-targeted agricultural practices and water and soil conservation works. The results obtained in the first part of the work show that AnnAGNPS model performs well in simulating runoff and sediment yields at the watershed scale. Furthermore the analysis carried out shows that the model is an efficient tool to assess the influence of different management options in the long term and in different weather conditions.

The aim of this study is to investigate the infl uence of different land management options on the sediment load at the watershed scale. To reach this, the Annualized agricultural non-point source model was used in the Candelaro basin (2300 km2). The watershed is located in a semi-arid area of southern Italy (Puglia region) and is affected by extensive erosion processes on the hillslopes. The sediment transport simulations have been compared with the 15 years (1970–1984) data coming from measures taken in two sub-watersheds (Vulgano and Salsola). Later, the model has been applied for a period of 24 years (1985–2008) to evaluate the effects of different land management options on the sediment yield: traditional best management practices, environmentally targeted agricultural practices and water and soil conservation works. The results obtained in the fi rst part of the work show that the Annualized agricultural non-point source model performs well in simulating runoff and sediment yields at the watershed scale. Furthermore, the analysis carried out shows that the model is an effi cient tool to assess the infl uence of different management options in the long term and in different weather conditions. Keywords: AnnAGNPS model, sediment yield, soil erosion, surface runoff, watershed management

In Northern Puglia watershed's high rates of suspended sediment loads occur along the hydrographic network during intense rainfall events. In order to monitor this phenomenon an automated station, equipped with a turbidity probe, has been set up in the Carapelle torrent. A laboratory testing stage of the turbidity probe was preliminary designed to evaluate the dual functionality of the instrument (turbidity and suspended solids) in relation with the sediment concentration and the grain size distribution. Successively a field calibration of the instrument was carried out to determine the relationship between optical and gravimetric data and to check the housing device. Afterwards, the high temporal resolution data collected over a 2-year period (2007-2008) were used to analyze the sediment transport dynamics at event scale. © 2009 Elsevier B.V. All rights reserved.

This work focuses on the monitoring and modeling of suspended sediment concentration in rivers in semi-arid environments. The optical technology is used in the Carapelle torrent (Southern Italy) for continuous measurements in order to capture the flows that effectively contribute to the sediment transport. High temporal resolution data, recorded in the period 2007-2010, were analyzed to investigate the relationships between suspended sediment concentration SSC and discharge Q. A possible trend of the suspended sediment transport in semiarid zones was evaluated considering the relationship between SSCmax and Qp at the event scale reported by other Authors. The continuous monitoring was the basis for modeling erosion and sediment transport at the basin scale. The AnnAGNPS model was calibrated and validated for runoff, peak discharge and sediment load.