Search results for "SED"
showing 10 items of 21612 documents
Testing Sediment Connectivity at the Experimental SPA2 Basin, Sicily (Italy)
2017
The concept of sediment delivery can be used as a measure of sediment connectivity, and it can be linked to the structural connectivity (morphological unit, slope length, slope steepness, travel time) of a basin and to the hydrological connectivity (rainfall–runoff processes at morphological unit scale). In this paper, the sediment connectivity concept was tested at basin scale applying SEdiment Delivery Distributed model, which takes into account the hillslope sediment transport, and using sediment yield measurements carried out at SPA2 experimental basin (Sicily, Italy). For the SPA2 basin discretized into morphological units, the SEdiment Delivery Distributed model was first calibrated a…
Testing simple scaling in soil erosion processes at plot scale
2018
Abstract Explaining scale effects for runoff and erosion improves our understanding and simulation ability of hydrological and erosion processes. In this paper, plot scale effects on event runoff per unit area (Qe), sediment concentration (Ce) and soil loss per unit area (SLe) were checked at El Teularet-Sierra de Enguera experimental site in Eastern Spain. The measurements were carried out for 31 events occurring in the years 2005 and 2007 in bare ploughed plots ranging from 1 to 48 m2. The analysis established the scaling relationship by dimensional analysis and self-similarity theory, and tested this relationship at different temporal scales ranging from event to annual scale. The dimens…
Applying the USLE Family of Models at the Sparacia (South Italy) Experimental Site
2016
Soil erosion is a key process to understand the land degradation, and modelling of soil erosion will help to understand the process and to foresee its impacts. The applicability of the Universal Soil Loss Equation (USLE) at event scale is affected by the fact that USLE rainfall erosivity factor does not take into account runoff explicitly. USLE-M and USLE-MM, including the effect of runoff in the event rainfall– runoff erosivity factor, are characterized by a better capacity to predict event soil loss. The specific objectives of this paper were (i) to determine the suitable parameterization of USLE, USLE-M and USLE-MM by using the dataseries of Sparacia experimental site and (ii) to evaluat…
Stage–Discharge Relationship for an Upstream Inclined Grid with Transversal Bars
2016
AbstractCheck dams with grids upgrading upstream are often used in mountain rivers, where intense sediment transport and steep slopes occur. In some cases, sloping grids are used in the construction of debris flow breakers. In this paper, the outflow process of an upstream-inclined grid with transversal bars is studied by using the dimensional analysis and the incomplete self-similarity theory. Next, the theoretical analysis shows that a power equation can be used for establishing the stage-discharge equation. The coefficient of the power equation depends on both the slope angle and the void ratio, whereas the exponent depends only on the slope angle. Finally, this deduced stage–discharge r…
Mountain building in NW Sicily from the superimposition of subsequent thrusting and folding events during Neogene: structural setting and tectonic ev…
2017
We present a 1:25.000 scale geological map of the Kumeta-Pizzuta ridge in north-western Sicily (Italy), achieved by integrating stratigraphic, structural and geophysical data. In this area, the tectonic edifice results from the piling-up of deep-water-, carbonate platform- and pelagic platform-derived tectonic units (Imerese and Sicilide, Panormide and Trapanese domains, respectively) resulting from deformations of the former southern Tethyan continental margin. The structural setting shows interference of tectonic events, different types of structural styles and different scales of deformational patterns. Early overthrust of the Imerese on the Trapanese units (since the late Serravallian) …
An Integrated Multiscale Method for the Characterisation of Active Faults in Offshore Areas. The Case of Sant’Eufemia Gulf (Offshore Calabria, Italy)
2021
Diagnostic morphological features (e.g., rectilinear seafloor scarps) and lateral offsets of the Upper Quaternary deposits are used to infer active faults in offshore areas. Although they deform a significant seafloor region, the active faults are not necessarily capable of producing large earthquakes as they correspond to shallow structures formed in response to local stresses. We present a multiscale approach to reconstruct the structural pattern in offshore areas and distinguish between shallow, non-seismogenic, active faults, and deep blind faults, potentially associated with large seismic moment release. The approach is based on the interpretation of marine seismic reflection data and …
The Graham Bank (Sicily Channel, central Mediterranean Sea). Seafloor signatures of volcanic and tectonic controls
2018
Abstract Graham Bank is a dominant physiographic element of the NW Sicily Channel (central Mediterranean Sea), affected in the last 100 years by numerous well-documented volcanic eruptions. We present the first results of a geomorphological study where the Graham Bank region in the depth interval 7–350 m was mapped for the first time with multi-beam echosounder and high-resolution seismic and multi-channel seismic reflection profiles. We describe in high resolution the detailed geomorphological features of Graham Bank, and how the superficial expression of different process and dynamics occurring in the sub-seafloor evidence volcanic and tectonic controls on seafloor morphology across a rel…
Occurrence, distribution, and risk assessment of pharmerciuticals in wastewater and open surface drains of peri-urban areas: Case study of Juja town,…
2020
Abstract The occurrence of Active Pharmaceutical Ingredients (APIs) in the environment is becoming a major area of concern due to their undesirable effects on non-target organisms. This study investigated the occurrence and risk of contamination by five antibiotics and three antiretrovirals drugs in a fast-growing peri-urban area in Kenya, with inadequate sewer system coverage. Due to poor sewage connectivity and poorly designed decentralized systems, wastewater is directly released in open drains. Water and sediment samples were collected from open surface water drains, while wastewater samples were collected from centralized wastewater treatment plants (WWTP). Solid-phase extraction and u…
Evidence of active fluid seepage (AFS) in the southern region of the central Mediterranean Sea
2018
Abstract Active fluid seepage (AFS) at the seafloor is a global phenomenon associated with seafloor morphologies in different geodynamic contexts. Advanced geophysical techniques have allowed geoscientists to characterise pockmarks, mounds and flares associated with AFS. We present a range of new marine geological data acquired in the southern region of the central Mediterranean Sea (northern Sicily continental margin, northwestern Sicily Channel and offshore of the Maltese Islands), which allow us to identify AFSs. AFSs are spatially distributed as clusters, aligned or isolated at different depths, ranging from few decametres offshore of the Maltese Islands; up to 400 m offshore of norther…
Eustasy and sea water Sr composition: application to high-resolution Sr-isotope stratigraphy of Miocene shallow-water carbonates
2007
Oceanic 87 Sr/ 86 Sr-isotope ratios are strongly influenced by rates of silicate weathering and therefore linked not only to glaciation but also to sea-level change. The present study combines analysis of sequence stratigraphy and basin architecture with Sr-isotope stratigraphy in Miocene shallow-water sediments in southern Portugal and Crete (Greece). The common method is to use smoothed global sea water Sr-isotope reference curves but here a different approach is chosen. Instead, measured Sr-isotope curves are correlated with unsmoothed reference curves by identification of similar fluctuations in the order of several 100 kyr. Transgressive intervals are characterized by increasing Sr-iso…