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Moramarco T.,CNR Research Institute for Geo-hydrological Protection | Barbetta S.,CNR Research Institute for Geo-hydrological Protection | Pandolfo C.,Umbria Region Functional Center | Tarpanelli A.,CNR Research Institute for Geo-hydrological Protection | And 2 more authors.
Journal of Hydrologic Engineering | Year: 2014

A large number of dams were built in Italy in the first decades of the last century to supply the needs of industrial, electric power, agricultural, and drinking purposes. Among them, the Montedoglio dam, an important reservoir on the Tiber River located in central Italy, with a drainage area of 276 km2 and a maximum storage volume of about 153 Mm3. The dam is an earth-fill structure with overfall spillway partly controlled by two sluice gates. On December 29, 2010, due to the partial sudden collapse of the spillway, a huge volume of water flooded the valley below the dam, severely damaging the territory, but luckily without causalities. Considering that scarce data are available for this type of event worldwide, this paper aims to illustrate the collected data of the studied event in terms of reservoir levels, using a discharge hydrograph observed at downstream gauged river sites and the flooded valley area. This study aims also to simulate the breach evolution and the downstream propagation of the outflow. Considering the Nash-Sutcliffe performance measure in simulation of the recorded reservoir levels, the time of breach formation and the corresponding discharge coefficient are obtained through an optimization procedure, yielding values of 0.02 h and 0.15, respectively. Finally, the Manning roughness coefficients for the downstream main channel and the floodplain areas are detected through a methodology based on one-dimensional hydraulic modeling by considering different flooding scenarios of valley. © 2014 American Society of Civil Engineers.

Brocca L.,CNR Research Institute for Geo-hydrological Protection | Ponziani F.,Umbria Region Functional Center | Moramarco T.,CNR Research Institute for Geo-hydrological Protection | Melone F.,CNR Research Institute for Geo-hydrological Protection | And 2 more authors.
Remote Sensing | Year: 2012

Predicting the spatial and temporal occurrence of rainfall triggered landslides represents an important scientific and operational issue due to the high threat that they pose to human life and property. This study investigates the relationship between rainfall, soil moisture conditions and landslide movement by using recorded movements of a rock slope located in central Italy, the Torgiovannetto landslide. This landslide is a very large rock slide, threatening county and state roads. Data acquired by a network of extensometers and a meteorological station clearly indicate that the movements of the unstable wedge, first detected in 2003, are still proceeding and the alternate phases of quiescence and reactivation are associated with rainfall patterns. By using a multiple linear regression approach, the opening of the tension cracks (as recorded by the extensometers) as a function of rainfall and soil moisture conditions prior the occurrence of rainfall, are predicted for the period 2007-2009. Specifically, soil moisture indicators are obtained through the Soil Water Index, SWI, a product derived by the Advanced SCATterometer (ASCAT) on board the MetOp (Meteorological Operational) satellite and by an Antecedent Precipitation Index, API. Results indicate that the regression performance (in terms ofcorrelation coefficient, r) significantly enhances if an indicator of the soil moisture conditions is included. Specifically, r is equal to 0.40 when only rainfall is used as a predictor variable and increases to r = 0.68 and r = 0.85 if the API and the SWI are used respectively. Therefore, the coarse spatial resolution (25 km) of satellite data notwithstanding, the ASCAT SWI is found to be very useful for the prediction of landslide movements on a local scale. These findings, although valid for a specific area, present new opportunities for the effective use of satellite-derived soil moisture estimates to improve landslide forecasting. © 2012 by the authors.

Brocca L.,CNR Research Institute for Geo-hydrological Protection | Tarpanelli A.,CNR Research Institute for Geo-hydrological Protection | Moramarco T.,CNR Research Institute for Geo-hydrological Protection | Melone F.,CNR Research Institute for Geo-hydrological Protection | And 7 more authors.
Vadose Zone Journal | Year: 2013

Knowledge of soil moisture is of upmost importance for many applications (e.g., flood and landslide prediction). In alpine areas, its estimation is difficult mainly due to complex topography and presence of snow. In this study, modeled and satellite data obtained by the Advanced SCATterometer have shown good agreement with in situ observations. Soil moisture is widely recognized as a state variable governing the mass and energy balance between the land surface and the atmosphere. For that, its knowledge is of upmost importance for many applications including flood and landslide prediction. In alpine catchments, soil moisture estimation is a very difficult task, because of complex topography, high vegetation density, and presence of snow and outcrops. In this study, the possibility to estimate soil moisture for these areas by using modeled and satellite data is investigated. Specifically, an updated version of a soil water balance model, which takes the snowmelt process into account, is employed. Moreover, satellite-derived soil moisture observations obtained by the Advanced SCATterometer (ASCAT) sensor onboard the MetOp satellite are tested by considering two products: the Surface Soil Moisture (SSM) and the Soil Water Index (SWI). The latter is obtained through the application of an exponential filter and it is aimed to reduce the differences in the layer depth of in situ measurements (10 cm) and satellite data (~2-3 cm). Quality-checked in situ soil moisture measurements collected at four continuous monitoring sites in Valle d'Aosta (North Italy) are used to test the accuracy of modeled and satellite estimates. Notwithstanding the above issues, results indicated the potential not only of modeling approaches but also, unexpectedly, of satellite data to retrieve soil moisture in high elevation regions (>1000 m a.s.l.). Indeed, by estimating correctly the snowmelt contribution, the agreement between modeled and observed data is quite good, with correlation coefficient values, r, in the range 0.795-0.940. In addition, the ASCAT-derived SWI product provides satisfactorily results with r = 0.635-0.869. Based on these findings, in situ, modeled, and satellite soil moisture data will be used for improving flood and landslide risk prediction at the Valle d'Aosta Functional center to improve the Civil Protection Alert System. © Soil Science Society of America 5585 Guilford Rd., Madison, WI 53711 USA. All rights reserved.

Ribarova I.,University of Architecture, Civil Engineering and Geodesy | Ninov Pl.,University of Architecture, Civil Engineering and Geodesy | Volk M.,Helmholtz Center for Environmental Research | Melone F.,CNR Research Institute for Geo-hydrological Protection | And 6 more authors.
Integrating Water Systems - Proceedings of the 10th International on Computing and Control for the Water Industry, CCWI 2009 | Year: 2010

In the scope of the EU funded project FLOODMED eight rainfall-runoff models (HEC-HMS, Vflo™, TRIMR2D, MISD, MIKE-DRiFT, HSPF, Mike NAM and VIDRA) were applied in flood simulations and were compared using thirteen indicators. In order to account for the varieties of flood-prone catchments, the models were run in seven European catchments, differing in area, altitude ranges and mean precipitation. All models were found to give satisfactory results in terms of precision and applicability. The main problems, common to the simulations of the flood events, were associated with data availability and accuracy (lack of high resolution data of rainfall and streamflow, lack of detailed soil data, and errors in the measurement of stages and discharges for high floods). This underlines the need to: i) improve data availability and quality and ii) consider uncertainty in model simulations. © 2010 Taylor & Francis Group, London.

Ponziani F.,Umbria Region Functional Center | Pandolfo C.,Umbria Region Functional Center | Stelluti M.,Umbria Region Functional Center | Berni N.,Umbria Region Functional Center | And 2 more authors.
Landslides | Year: 2012

Rainfall thresholds represent the main tool for the Italian Civil Protection System for early warning of the threat of landslides. However, it is well-known that soil moisture conditions at the onset of a storm event also play a critical role in triggering slope failures, especially in the case of shallow landslides. This study attempts to define soil moisture (estimated by using a soil water balance model) and rainfall thresholds that can be employed for hydrogeological risk prevention by the Civil Protection Decentrate Functional Centre (CFD) located in the Umbria Region (central Italy). Two different analyses were carried out by determining rainfall and soil moisture conditions prior to widespread landslide events that occurred in the Umbria Region and that are reported in the AVI (Italian Vulnerable Areas) inventory for the period 1991-2001. Specifically, a "local" analysis that considered the major landslide events of the AVI inventory and an "areal" analysis subdividing the Umbria Region in ten sub-areas were carried out. Comparison with rainfall thresholds used by the Umbria Region CFD was also carried out to evaluate the reliability of the current procedures employed for landslide warning. The main result of the analysis is the quantification of the decreasing linear trend between the maximum cumulated rainfall values over 24, 36 and 48 h and the soil moisture conditions prior to landslide events. This trend provides a guideline to dynamically adjust the operational rainfall thresholds used for warning. Moreover, the areal analysis, which was aimed to test the operational use of the combined soil moisture-rainfall thresholds showed, particularly for low values of rainfall, the key role of soil moisture conditions for the triggering of landslides. On the basis of these results, the Umbria Region CFD is implementing a procedure aimed to the near real-time estimation of soil moisture conditions based on the soil water balance model developed ad hoc for the region. In fact, it was evident that a better assessment of the initial soil moisture conditions would support and improve the hydrogeological risk assessment. © 2011 Springer-Verlag.

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