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In the Mediterranean area, soil erosion is a physical process of degradation caused by losing particles from soil surface due to raindrop impact and run-off events. It is important to analyse and study erosion effects on hydraulic constructions, river-beds and so on, because predicting soil loss is necessary to establish and value the soil conserva...
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... every average annual R value to the respective polygon in the "shape" file and then converting the "shape" file in a raster file with a cell size of 20 metres, we obtained the file as shown in figure 4, in which the catchment is divided in parts with a specific R value. Finally, we converted the raster file in the respective ASCII file by using the "Raster to ASCII" GIS function, obtaining the file "pioggia.asc". Montedoglio has two main pedologic system: the "Alpe della Luna e rilievi intorno a Sestino" system and the "Pratomagno e Alpe di Catenaia" ...
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... can calculate the exact annual average value of SDR for Montedoglio's catchment because we know by bathymetry the exact amount of sediments deposited in the lake (S p = annual average effective soil loss in the catchment) and by RUSLE equation the theoretic quantity of sediments moved every year (S t = annual average quantity of soil moved in the catchment). This value shows how much more than half-eroded soil arrives every year (≈ 60%) to the lake located in correspondence with the downstream section of the basin. It also shows how the remaining part sediments due to the variation of acclivity, the superficial roughness, the permeability, the presence of vegetation, etc.. So the sediment delivery ratio depends on factors such as the typology of erosion (interrill, rills, gullies), the characteristics of sediment delivery system, the characteristics of the catchment, the texture of eroded soil, the conditions of vegetal cover etc. 16,17 . To verify the good quality of the SDR value determinated, we have analyzed the influence of the total length of the channel system, the influence of the superficial characteristics, the influence of the slopes and the granulometric composition of eroded soil. Firstly, we have observed that the SDR value is directly proportionate with the branching of the channel system. In fact, the more the system is branched the more the density of drainage is high and the sediments easily arrive to the channels, or even to the downstream section. We have calculated the channel system and its length by using the GRASS v6.2 as software and the DEM of the catchment area as input file. As a first step, we converted the original DEM into a DEM without depressions ("DEM fill") by using r.fill.dir command, that allowed us to create a continuous channel system. We then calculated by r.watershed command the drainage lines and the stream map, resulting in a total length of about 733.76 km ( figure 14). We were then able to calculate the drainage density, a morphometric quantity obtained by the ratio between the total length of the channels in kilometres and the area of the catchment in kilometres 2 , showing how the catchment is divided in valleys. Analyzing the channel system obtained, we observed a good drainage density, typical of superficial lithologies with a low permeability, that doesn't allow the formation of intermediate re-depositions areas 18 . Secondly, we know 16 that the average acclivity of the basin proportionality increases with the increase of the hillslopes and the inclination of the channels. Consequently the transport of eroded soil is easier. Analyzing the hillslope map ( figure 15), we can observe that the catchment has an high average slope (≈ 16°) and a not excessive areal extension (≈ 276 km 2 ), a typical characteristic of mountainous catchments, thus advantaging the transport of the sediments. Finally, the SDR values increase when the content of clay increases in the running off solutions, composed of water and eroded soil, and it decreases when the size of the sediments increases in the water. We analyzed the lithologic map of the high part of the Tevere's catchment 19 ( figure ...
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... Inteferometry is, in the strict sense, the measurement of variations of SAR signal between two distinct variations, coming from the same target. A movement of terrain [1] changes the distance between sensor and target, and this modification implies a variation in the signal phase, as represented in Fig.1. We can denote the interferometric phase variation (Δφ) with a simple mathematical relationship as 4 R π ϕ α λ ∆ = ∆ + (1) where λ is the wavelength, ΔR is the displacement while α represents the phase variation related to the atmosphere in the two acquisitions (with an inevitable noise contribution). ...
... A movement of terrain [1] changes the distance between sensor and target, and this modification implies a variation in the signal phase, as represented in Fig.1. We can denote the interferometric phase variation (Δφ) with a simple mathematical relationship as 4 R π ϕ α λ ∆ = ∆ + (1) where λ is the wavelength, ΔR is the displacement while α represents the phase variation related to the atmosphere in the two acquisitions (with an inevitable noise contribution). Eq.(1) illustrates a displacement equal to half of the wavelength, generated by interferometric phase of 2π, that is a phase cycle. ...
The effects of landslide and erosion can be detected and monitored by airborne-based systems, and in particular by satellite using InSAR (interferometry by Synthetic Aperture Radar). The interferogram is applied here as an innovating tool to predict mid and long term effects of landslide and erosion. SAR images are generally found to be contaminated with a special type of highly unordered and chaotic noise pattern termed as speckle noise. When an object is illuminated by a coherent source of radiation and the object has a surface structure that is roughly of the order of the wavelength of the incident radiation, the wave reflected from such a surface consists of contributions from many independent scattering areas. Even though, the research has used them with appropriate sub-techniques improve their efficiency in landslide and erosion detection.
... Geothermal energy is a renewable source of an important form of energy, coming from subsoil [1]. To use it, it is necessary to design geothermal vertical exchangers (geothermal probes) even if it is very complex to design them because of the presence of multiple possible lithotypes, which values of thermal conductivity in W/mk, necessary for the calculation of the thermal resistance, influence, in a certain way, their dimensions. ...
Vertical geothermal exchangers (geothermal probes) are very complex, especially in presence of diverse and possible lithotypes which values of thermal conductivity expressed in W/mk, are necessary for the determination of thermal resistance; they also influence the design of the thermal probe. One the simplified methods to design thermal probes is based on its capability to interact with lithostratigraphy that permits to know the thermal conductivity. The efficiency of the thermal probe is highly related to the nature of the filling fluid because it steers the thermal exchange with the soil under test. That is why it is important to study and formulate ad hoc mixture.
... Methods of detection, used to control active landslide, are based on: control of fixed points (GPS, total station, digital levels) or areas of control (airphotos, laser scanner from airplane, terrestrial laser scanner, interferometry SAR). Detecting methods through triangulation [1] and laser-based distance measurements allow to obtain a high accuracy (sub-centimetric). ...
Landslide is a dangerous phenomenon according to geomechanical viewpoint, being able to produce huge damages because of sliding and can involve structures and infrastructures. However, mechanical aspects are generally recognized since they provoke the above consequences. Environmental aspects related to breaking in the land must be considered. Land breaks or cracks allow outside water, not only from rain, to reach surface and subterranean aquifers. Contacts between external waters, maybe containing diverse pollutants, and aquifers, would be considered as source of contamination. The paper illustrates an experimental multi-temporal monitoring of landslides that have been taking place at Colletorto town (Italy). The proposed method, by means of dedicated instrumentation, and subsequent modeling, has permitted to output innovating approach.
... The model showed good performance in a range of environments, explaining a large proportion of the variance in sediment yields for nested watersheds in United States . Other studies conducted with the original algorithm developed by Borselli also found that the model was able to predict variability in sediment yields in Italy, South-East Australia and Hawai'i (Cavalli et al., 2013;Falinski, 2016;Leombruni et al., 2009;Vigiak et al., 2012). ...
Geospatial models are commonly used to quantify sediment contributions at the watershed scale. However, the sensitivity of these models to variation in hydrological and geomorphological features, in particular to land use and topography data, remains uncertain. Here, we assessed the performance of one such model, the InVEST sediment delivery model, for six sites comprising a total of 28 watersheds varying in area (6–13,500 km²), climate (tropical, subtropical, mediterranean), topography, and land use/land cover. For each site, we compared uncalibrated and calibrated model predictions with observations and alternative models. We then performed correlation analyses between model outputs and watershed characteristics, followed by sensitivity analyses on the digital elevation model (DEM) resolution. Model performance varied across sites (overall r² = 0.47), but estimates of the magnitude of specific sediment export were as or more accurate than global models. We found significant correlations between metrics of sediment delivery and watershed characteristics, including erosivity, suggesting that empirical relationships may ultimately be developed for ungauged watersheds. Model sensitivity to DEM resolution varied across and within sites, but did not correlate with other observed watershed variables. These results were corroborated by sensitivity analyses performed on synthetic watersheds ranging in mean slope and DEM resolution. Our study provides modelers using InVEST or similar geospatial sediment models with practical insights into model behavior and structural uncertainty: first, comparison of model predictions across regions is possible when environmental conditions differ significantly; second, local knowledge on the sediment budget is needed for calibration; and third, model outputs often show significant sensitivity to DEM resolution.
... Accommodation rates were minimal during lowstand and terrigenous sediment bypass into the basin. This might explain the large compositional range of the deposits, with compositional variation dictated by the nuances of relative rainfall and/or discharge in the paleo-Tiber subcatchments as seen today (e.g., Leombruni et al. 2009). The higher Qm/(Qm þ Lt) ratio compared to the highstand sands might be explained by taking into consideration the major areal extent of volcaniclastic and sedimentary formations in the Tiber River drainage during the PGS highstand (Fig. 12). ...
Sand composition is one of the factors of a stratigraphic succession that best records the interaction
between allogenic and autogenic processes. This is particularly true for the Quaternary successions where the effects of this processes are better recognized and differentiated. The Quaternary succession of the Roman Basin and, in particular, the one developed during the late early Pleistocene to Holocene, records a close interaction among tectonic uplift, volcanism, climate, and glacio-eustasy. Such interaction is reflected in a complex stratal pattern and stratigraphic architecture where high-rank and low-rank depositional sequences are developed and where qualitative and quantitative changes in sand composition are recorded in the same systems tracts. The analyzed succession corresponding to the high-rank Ponte Galeria sequence (PGS) was supplied by the Tiber River and its tributaries, which developed along the Latium Tyrrhenian margin; such deposits include sediment derived from carbonate to siliciclastic Meso-Cenozoic rocks and from Pleistocene volcanic complexes of the Roman Magmatic Province. We defined three main sand petrofacies (A, B, C) that have a good correspondence with lowstand (LST), transgressive (TST), and highstand (HST) systems tracts of PGS, which reflect changes in sand composition and sand provenance under the effects of tectonism, volcaniclastic input, sedimentary processes, and relative sea-level variations. Petrofacies A is feldspatho-litho-quartzose to feldspatho-quartzo-lithic in composition. It records the erosion and influx of siliciclastic and carbonate rock detritus without volcanic input into the LST fluvial and coastal sands of the PGS. Petrofacies B is characterized by a modal composition varying from feldspathic to litho-feldspathic and feldspatho-quartzo-lithic. It characterizes the TST of the PGS and reflects the abrupt and rapid introduction of volcaniclastic sediment into the system. Petrofacies C is feldspatho-quartz-lithic in composition. This petrofacies characterizes the HST of PGS and, with respect to the other two petrofacies, better records the effects of downstream transport and river-mouth sedimentary processes. Sand samples collected from ancient deposits are similar in composition to the modern Tiber River, suggesting provenance from a similar river system. Results show that tectonism during middle–upper Pleistocene volcanic activity in the Sabatini, Cimini, and Vulsini volcanic complexes played a major role controlling stream-network reorganization in the Tiber drainage basin and resulted in enhanced volcaniclastic input from ash fall and recycling of pyroclastic flows. Volcanic input (volcanic lithics and associated phenocrysts) and postdepositional alteration during paleosol development define pre-, syn-, and post-volcanic compositions in the high-rank Ponte Galeria depositional sequence. In low-rank depositional sequences, several processes produced variable quartz/feldspar and quartz/lithic ratios, as well as textural changes; these include hydraulic sorting during fluvial and coastal transport and postdepositional in situ weathering processes. Weathering and pedogenic processes in the source area (catchment) potentially remove provenance information, reducing correlation potential of petrographic signatures of proximal successions in the Tiber River sedimentary basin. This work tests the effectiveness of using variation in sand composition as a tool in sequence stratigraphy.
... Our analyses in Cape Fear confirm that the model can be used for a first order assessment of sediment dynamics. They add to a larger body of work illustrating the usefulness of the algorithms used, in subtropical, Mediterranean, and temperate climates (Jamshidi et al., 2014;Leombruni et al., 2009;Vigiak et al., 2012). These studies have shown how the algorithms can provide valuable information on the spatial distribution of sediment delivery ratios. ...
... These studies have shown how the algorithms can provide valuable information on the spatial distribution of sediment delivery ratios. Only Vigiak et al. (2012) presented an in-depth assessment of uncertainties in their modeling of seven subcatchments in South-East Australia: they report a relative mean root square error of 0.107 and 0.176 for the sediment yield and specific sediment yield, respectively, with a calibrated k b of 2. The performance of the model in the study by Leombruni et al. (2009) is less satisfying. With a k b of 1.5, which is not justified by the authors, they found an error of − 60% in the estimate of sediment load in the Montedoglio's lake, Italy. ...
There is a growing call for ecosystem services models that are both simple and scientifically credible, in order to serve public and private sector decision-making processes. Sediment retention receives particular interest given the impact of this service on water quality. We developed a new version of the sediment retention model for the InVEST (Integrated Valuation of Environmental Services and Tradeoffs) tool to address previous limitations and facilitate model uncertainty assessment. We tested the model in the Cape Fear basin, North Carolina (NC), performing sensitivity analyses and assessing its ability to detect the spatial variability in sediment retention service for eight subcatchments. The main advantages of the revised model include the use of spatially-explicit, globally available input data, and the explicit consideration of hydrological connectivity in the landscape. The sensitivity analyses in the study catchment identified the erosivity and erodibility factors, together with the cover factor for agricultural land as the most influential parameter for sediment export. Relative predictions, representing the spatial variability in sediment exports, were correctly represented by the model. Absolute sediment exports were also highly correlated with observations, although their interpretation for socio-economic assessments is more uncertain without local knowledge of the dominant erosion processes. This work confirms that the sediment connectivity approach used in the revised InVEST model has great potential to quantify the sediment retention service. Although resources to conduct model calibration and testing are typically scarce, these practices should be encouraged to improve model interpretation and for confident application in different decision-making contexts. Without calibration, the InVEST sediment model still provides relevant information for ecosystem services assessments, especially in decision contexts that involve ranking of sediment export areas, such as spatial prioritization of conservation, development or restoration activities, taking into account non-linear sediment responses to changes in land use.
Copyright © 2015 Elsevier B.V. All rights reserved.
... The type and distribution of land cover/land use was applied in this parameter as an indicator of impediment to the connectivity of entrained sediment materials along the overland flow path. This approach of catchment division was further validated by Leombruni et al. (2009) in the Montedoglio catchment, Italy and then refined by Vigiak et al. (2012). Through comparing different methods of SDR estimations in a catchment, the latter study showed that flux connectivity (IC) was the most appropriate and reliable approach in the prediction of sediment yields in small catchments where there is relative climatic homogeneity (Vigiak et al., 2012). ...
... The variability of sediment delivery is analysed by sub-dividing a catchment into 100-m 2 cell-size morpho- (Ferro and Minacapilli, 1995;Leombruni et al., 2009). The application of a spatially distributed calibration of sediment connectivity indices (IC) enables a more detailed analysis at fine resolution to link the processes of gross soil loss and potential sediment yield to stream networks. ...
... The downslope component accounts for the distance between the eroded area and the nearest depression or sink, which is affected by ground surface characteristics of roughness and slope. The downslope component, D dn represents downstream connectivity of a single unit in a hillslope, which is the sum of individual distances (d i ) along downstream paths to a stream network (Borselli et al., 2007;Leombruni et al., 2009). The intensity and degree by which a hillslope is able to facilitate downstream transport capacity is affected by an inverse proportion of superficial roughness and slope gradient of each cell along the hydraulic path (Borselli et al., 2007). ...
The intensity of soil loss and sediment delivery, representing hydrologic and geomorphic processes within a catchment, accelerates with rapid changes in land cover and rainfall events. An underlying component of sustainable management of water resources is an understanding of spatial and temporal variability and the adverse influences of regional parameters involved in generating sediment following widespread changes in land cover. A calibrated algorithm of soil loss coupled with a sediment delivery ratio (SDR) was applied in raster data layers to improve the capability of a combined model to estimate annual variability in sediment yields related to changes in vegetation cover identified by analyses of SPOT imagery. Four catchments in Kangaroo River State forest were assessed for annual changes in sediment yields. Two catchments were selectively logged in 2007, while the two other sites remained undisturbed. Results of SDR estimates indicated that only a small proportion of total eroded sediment from hillslopes is transported to catchment outlets. Larger SDR values were estimated in regions close to catchment outlets, and the SDR reduced sharply on hillslopes further than 200–300 m from these areas. Estimated sediment yield increased by up to 30% two years after land cover change (logging) in 2009 when more storm events were recorded, despite the moderate density of vegetation cover in 2009 having almost recovered to its initial pre-logging (2005) condition. Rainfall had the most significant influence on streamflow and sediment delivery in all catchments, with steeply sloping areas contributing large amounts of sediment during moderate and high rainfall years in 2007 and 2009. It is concluded that the current scenario of single-tree selection logging utilized in the study area is an acceptable and environmentally sound land management strategy for preservation of soil and water resources. Copyright © 2013 John Wiley & Sons, Ltd.
... The idea is to apply information technology to simple Gavrilovic formula in order to turn an empirical formula which needs extensive operator judgements to an automatic process with little, if not totally absent, operator influence and ideally applicable to basins of any dimension using little scale data. Applications like this have already been done with the more common USLE and RUSLE formulas, not suitable in Alpine regions as already seen, for instance by Baigorria and Romero [10], Jain and Debjyoti [11], Chou [12], Leombruni et al. [13] and Globevnik et al. [14]. The process has been tested on a little basin in Northern Italy called Rossiga valley. ...
Sediment yield and slope erosion represent nowadays an open problem for
Alpine river basins management. In the last decades a variety of methods to
estimate erosion rate and yield volumes have been studied and presented to the
scientific community; however these methods are often empirical and only
provide rough results. On the other hand the use of physical based methods
demands an enormous quantity of data that are difficult and costly to collect.
Moreover these data are affected by an intrinsic error due to the impossibility of
taking accurate parameter measurements. This paper focuses on the Gavrilovic
method that is considered a standard for erosion evaluation in Alpine regions;
this theory has proved to be effective and quite simple to be applied, but has a
major drawback in the subjectivity of parameter determination. Since 1973,
when this method was initially published, many things have changed and
computers have revolutionized the scientific world. The authors are convinced
that the use of a GIS support can automate the Gavrilovic method. GIS uses
advanced calculation methods based on high resolution geographic data; these
datasets allow one to eliminate or at least reduce the role of the operator in the
calculation processes. Moreover the whole basin can be automatically split into
little sub basins with similar features. This operation leads to an application field
more similar to the original testing site. The final objective is to present an
automated process that can produce a reliable prediction of sediment yield from
little and medium basins starting from DTM and use of soil maps, taking into
account also the rainfall distribution on the studied area. The new method is then
applied to a test site to demonstrate the improvements in time and efficiency this
innovation can lead to.
Keywords: Gavrilovic, sediment yield, soil loss, Alpine basin, GIS.
In the effort to reduce emissions, in particular those due to energy conversion and transformation, renewal energies can give a substantial contribution in this field. For house heating, direct exploitation of subsoil energy is a matter of great interest. To extract subsoil energyfor house utilization, a plant is needed. Among different parts and devices included in the plant dedicated to conversion and transmission, geothermal probe plays an important role. It is a special device allowing conversion from thermal energy to thermal energy with different enthalpy. It operates as a sensing system without changing the type of energy. In general, there are two types of probe: vertical and horizontal probes. The article illustrates the design, construction and testing of a high efficiency vertical polymergeothermal probe. A verification of flow/fluid measurement has been carried out.
Corporations and other multinational institutions are increasingly looking to evaluate their innovation and procurement decisions over a range of environmental criteria, including impacts on ecosystem services according to the spatial configuration of activities on the landscape. We have developed a spatially explicit approach and modeled a hypothetical corporate supply chain decision representing contrasting patterns of land-use change in four regions of the globe. This illustrates the effect of introducing spatial considerations in the analysis of ecosystem services, specifically sediment retention. We explored a wide variety of contexts (Iowa, USA; Mato Grosso, Brazil; and Jiangxi and Heilongjiang in China) and these show that per-area representation of impacts based on the physical characterization of a region can be misleading. We found two- to five-fold differences in sediment export for the same amount of habitat conversion within regions characterized by similar physical traits. These differences were mainly determined by the distance between land use changes and streams. The influence of landscape configuration is so dramatic that it can override wide variation in erosion potential driven by physical factors like soil type, slope, and climate. To minimize damage to spatially-dependent ecosystem services like water purification, sustainable sourcing strategies should not assume a direct correlation between impact and area but rather allow for possible nonlinearity in impacts, especially in regions with little remaining habitat and highly variable hydrological connectivity.
