Channel planform changes along the Scrivia River floodplain reach in northwest Italy from 1878 to 2016

2018 ◽  
Vol 91 (2) ◽  
pp. 620-637 ◽  
Author(s):  
Andrea Mandarino ◽  
Michael Maerker ◽  
Marco Firpo

AbstractA detailed, quantitative, multitemporal analysis of historical maps, aerial photos, and satellite images was performed to investigate the channel planform changes that occurred along the Scrivia River floodplain from 1878 to 2016. Various channel planform features, including channel length, area, width, braiding, sinuosity, lateral migration, activity, and stability, were computed through an innovative geographic information system–based procedure, starting from manually digitized active-channel polygons. Three active-channel morphological evolution stages are evident from: (1) 1878 to the 1950s; (2) the 1950s to the end of 1990s; and (3) the end of 1990s onward. In the first period, the river was generally able to migrate in its floodplain, shaping the riverscape. Active-channel narrowing and increasing channel stability characterize the second period. The most recent phase shows an inversion of the morphological evolutionary trend. This last phase is characterized by a slight generalized widening related to the reactivation of stabilized surfaces and to bank-erosion processes. Particularly from the 1950s to the 1990s, in-channel sediment mining and channelization with consequent occupation of riverine areas strongly affected the Scrivia River. These factors, together with floods, are thought to be the most likely causes of such consistent and fast morphological changes.

2021 ◽  
Vol 13 (18) ◽  
pp. 3775
Author(s):  
Andrea Mandarino ◽  
Giacomo Pepe ◽  
Andrea Cevasco ◽  
Pierluigi Brandolini

The active-channel planform adjustments that have occurred along the Centa, lower Arroscia and lower Neva rivers since 1930, along with the riverbed channelization processes and the land-use and land-cover changes in disconnected riverine areas, were investigated through a multitemporal analysis based on remote sensing and geographical information systems (GIS). These watercourses flow through the largest Ligurian alluvial-coastal plain in a completely anthropogenic landscape. This research is based on the integrated use of consolidated and innovative metrics for riverbed planform analysis. Specific indices were introduced to assess active-channel lateral migration in relation to the active-channel area abandonment and formation processes. The Arroscia and Neva riverbeds experienced narrowing, progressive stabilization, and braiding phenomena disappearance from 1930 to the early 1970s, and then slight narrowing up to the late 1980s. Subsequently, generalized stability was observed. Conversely, the Centa was not affected by relevant planform changes. Recently, all rivers underwent a slight to very slight width increase triggered by the November 2016 high-magnitude flood. The active-channel adjustments outlined in this paper reflect the relevant role in conditioning the river morphology and dynamics played by channelization works built from the 1920s to the early 1970s. They (i) narrowed, straightened, and stabilized the riverbed and (ii) reduced the floodable surface over the valley-floor. Thus, large disconnected riverine areas were occupied by human activities and infrastructures, resulting in a progressive increase in vulnerable elements exposed to hydrogeomorphic hazards. The outlined morphological dynamics (i) display significant differences in terms of chronology, type, and magnitude of active-channel planform adjustments with respect to the medium- and short-term morphological evolution of most Italian rivers and (ii) reflect the widespread urbanization of Ligurian major valley floors that occurred over the 20th century. The outcomes from this study represent an essential knowledge base from a river management perspective; the novel metrics enlarge the spectrum of available GIS tools for active-channel planform analysis.


2020 ◽  
Vol 42 (2) ◽  
pp. 176-186
Author(s):  
Cham Dao Dinh

In recent years, accretion-erosion processes are frequently recorded in the estuary of Cua Dai, Quang Nam province. Most recently, however, sand bars are formed in the estuary not far from the place where the Inland Waterways Authority of Vietnam had previously dredged. The estuary continues to be accreted by sand. These have been drawing special attention of national and international scientists. While there is accretion at the estuary, eroded processes are strongly recorded along the coastlines of Quang Nam province. Therefore, it is necessary to carry out a study in the effects of the hydrodynamic regime on morphological changes in the Cua Dai estuary and coastlines of Quang Nam province. The goal of this paper is to fully interpret the causes, regimes of accretion and erosion processes over the study area. In this study, satellite images and hydrodynamic models of Delft3D and MIKE 11 are applied. The results show a strong accretion process in the estuary of Cua Dai. Sandbar formation across the Cua Dai estuary comes from the interaction of flood, wave, and current conditions during the northeast monsoon. This mainly affects the changes in morphology in the estuary of Cua Dai, Quang Nam.


2020 ◽  
Vol 42 (2) ◽  
pp. 176-186
Author(s):  
Cham Dao Dinh

In recent years, accretion-erosion processes are frequently recorded in the estuary of Cua Dai, Quang Nam province. Most recently, however, sand bars are formed in the estuary not far from the place where the Inland Waterways Authority of Vietnam had previously dredged. The estuary continues to be accreted by sand. These have been drawing special attention of national and international scientists. While there is accretion at the estuary, eroded processes are strongly recorded along the coastlines of Quang Nam province. Therefore, it is necessary to carry out a study in the effects of the hydrodynamic regime on morphological changes in the Cua Dai estuary and coastlines of Quang Nam province. The goal of this paper is to fully interpret the causes, regimes of accretion and erosion processes over the study area. In this study, satellite images and hydrodynamic models of Delft3D and MIKE 11 are applied. The results show a strong accretion process in the estuary of Cua Dai. Sandbar formation across the Cua Dai estuary comes from the interaction of flood, wave, and current conditions during the northeast monsoon. This mainly affects the changes in morphology in the estuary of Cua Dai, Quang Nam.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Consuele Morrone ◽  
Fabio Ietto

AbstractThis contribution focuses on a multidisciplinary research showing the geomorphological evolution and the beach sand composition of the Tyrrhenian shoreline between Capo Suvero promontory and Gizzeria Lido village (Calabria, southern Italy). The aim of the geomorphological analysis was to reconstruct the evolutionary shoreline stages and the present-day sedimentary dynamics along approximately 6 km of coastline. The results show a general trend of beach nourishment during the period 1870–2019. In this period, the maximum shoreline accretion value was estimated equal to + 900 m with an average rate of + 6.5 m/yr. Moreover, although the general evolutionary trend is characterized by a remarkable accretion, the geomorphological analysis highlighted continuous modifications of the beaches including erosion processes. The continuous beach modifications occurred mainly between 1953 and 1983 and were caused mainly by human activity in the coastal areas and inside the hydrographic basins. The beach sand composition allowed an assessment of the mainland petrological sedimentary province and its dispersal pattern of the present coastal dynamics. Petrographic analysis of beach sands identified a lithic metamorphi-clastic petrofacies, characterized by abundant fine-grained schists and phyllites sourced from the crystalline terrains of the Coastal Range front and carried by the Savuto River. The sand is also composed of a mineral assemblage comparable to that of the Amato River provenance. In terms of framework detrital constituents of QFL (quartz:feldspars:aphanitic lithic fragments) and of essential extraclasts, such as granitoid:sedimentary:metamorphic phaneritic rock fragments (Rg:Rs:Rm), sand maturity changes moderately from backshore to shoreface, suggesting that transport processes had a little effect on sand maturity. Moreover, the modal composition suggests that the Capo Suvero promontory does not obstruct longshore sand transport from the north. Indeed, sands displaced by currents driven by storm-wave activity bypass this rocky headland.


Ocean Science ◽  
2017 ◽  
Vol 13 (5) ◽  
pp. 673-690 ◽  
Author(s):  
Guilherme Franz ◽  
Matthias T. Delpey ◽  
David Brito ◽  
Lígia Pinto ◽  
Paulo Leitão ◽  
...  

Abstract. Coastal defence structures are often constructed to prevent beach erosion. However, poorly designed structures may cause serious erosion problems in the downdrift direction. Morphological models are useful tools to predict such impacts and assess the efficiency of defence structures for different scenarios. Nevertheless, morphological modelling is still a topic under intense research effort. The processes simulated by a morphological model depend on model complexity. For instance, undertow currents are neglected in coastal area models (2DH), which is a limitation for simulating the evolution of beach profiles for long periods. Model limitations are generally overcome by predefining invariant equilibrium profiles that are allowed to shift offshore or onshore. A more flexible approach is described in this paper, which can be generalised to 3-D models. The present work is based on the coupling of the MOHID modelling system and the SWAN wave model. The impacts of different designs of detached breakwaters and groynes were simulated in a schematic beach configuration following a 2DH approach. The results of bathymetry evolution are in agreement with the patterns found in the literature for several existing structures. The model was also tested in a 3-D test case to simulate the formation of sandbars by undertow currents. The findings of this work confirmed the applicability of the MOHID modelling system to study sediment transport and morphological changes in coastal zones under the combined action of waves and currents. The same modelling methodology was applied to a coastal zone (Costa da Caparica) located at the mouth of a mesotidal estuary (Tagus Estuary, Portugal) to evaluate the hydrodynamics and sediment transport both in calm water conditions and during events of highly energetic waves. The MOHID code is available in the GitHub repository.


2021 ◽  
Vol 38 (5) ◽  
pp. 312-318
Author(s):  
Wiliam Carvajal Veitía ◽  
Sofía Alberta León Pérez ◽  
María Elena González Revuelta ◽  
Yanel Deturnel Campo

Objective: To evaluate the morphological changes of Cuban super heavyweight boxers, more and less successful, through the period 1976-2014. Material and method: Thirty super heavy boxers, who were members of the Cuban national teams in the period 1976-2014, were compared; The strategy consisted of separating the group in the periods 1976-1989, 1990-1999, 2000-2009 and 2010-2014. Sixteen anthropometric dimensions were recorded (weight, height, sitting height, six skinfold thickness, five girths and two breadths), from which the body composition and the somatotype were obtained. The data were analyzed applying the Analysis of variance (ANOVA). The conglomerate analysis based on the Euclidean distance was used in order to evaluate the correspondence between physical development and sports performance. A discriminant analysis was carried out in order to analyze the contribution of the anthropometrical variables to the variance of different clusters. Results: Most of the anthropometric dimensions and indicators showed significant differences, having an impact on the increase in adiposity, body fat and endomorphy (p <0.05), as well as the decrease in the indicators dependent on height (p <0.05). The analysis by conglomerates, as well as the study of the Migratory Distances of the somatotype, showed that the Olympic medalist boxers differed in terms of the characteristics of body composition and in terms of the intensity of the somatotype changes in the period 1976-2014. Conclusions: The Cuban boxer of the super heavyweight category showed a wide range of morphological demands, but these were framed within the international trends of professional boxers. The morphological attributes of the Olympic medalists differed from each other, and from the rest of the boxers investigated over time. These results provide anthropometric data of high scientific value, both for selection and for medical control of training.


Paleobiology ◽  
1996 ◽  
Vol 22 (3) ◽  
pp. 386-405 ◽  
Author(s):  
Richard D. Norris ◽  
Richard M. Corfield ◽  
Julie Cartlidge

Analysis of the evolution of the Globorotalia (Fohsella) lineage of planktic foraminifera suggests that reproductive ecology and shell shape have evolved independently in this group. The silhouette of fohsellid shells displays a nearly unbroken anagenetic trend, yet isotopic data show that the fohsellids changed their depth of reproduction during the anagenetic evolution of their skeletons. Remarkably, there are no correlations between anagenesis in skeletal shape and the establishment of reproductive isolation. Apparently, anagenesis masks at least one speciation event that is apparent only in the isotopic evidence for a change in reproductive ecology. Although anagenetic trends have been widely cited as evidence for gradual speciation in planktic foraminifera and other microfossil groups, our data suggest that they should not always be considered to record either the tempo or mode of speciation.Speciation was apparently uncoupled from morphological evolution in fohsellids because these evolutionary phenomena occurred in different phases of ontogeny. Gradual morphological changes were associated with the main phase of shell growth of both the ancestor and descendant species in the near-surface ocean. Reproductive isolation occurred when ancestral and descendant populations became established at different depths near the end of the life cycle. Morphological evolution may also be uncoupled from reproductive isolation in other organisms that experience very different selection pressures over the duration of their ontogenies, such as parasites with many hosts, species with multiple phases of metamorphosis, and organisms that broadcast their gametes.


2020 ◽  
Vol 12 (3) ◽  
pp. 482 ◽  
Author(s):  
Marek Kasprzak ◽  
Michał Łopuch ◽  
Tadeusz Głowacki ◽  
Wojciech Milczarek

The article presents geomorphological analysis results for two outwash fans (sandurs), Elveflya and Nottingham, in the marginal zone of the Werenskiold Glacier in the south-west part of the Spitsbergen. The main goal of this study was to reconstruct the morphological evolution of these landforms and to identify the permafrost zone under their surface. For this purpose, age data of fossils were compiled and compared with newly exposed and dated fossil tundra in the layer glaciotectonically deformed by the forming glacier end moraine. Using this method, a time frame was identified for the glacier advance and for the simultaneous formation of the outwash plains. It was concluded that the Elveflya surface has been built-up with deposits since the Little Ice Age. Sediment deposition ended in the late 1960s, due to hydrographic changes and the redirection of all proglacial waters towards the Nottingham bay. A photointerpretation analysis based on two orthophotomaps and LANDSAT scenes allowed the identification of five microfans in Elveflya, of which two youngest fans have a twice shorter range than the other three. The sixth microfan is currently shaped by deposits washed from the slope of the end moraine. An additional focus was placed on a currently active sandur, which fills the Nottingham bay, in order to identify its growth rate. The average growth rate of this surface increased from 5700 m2·year−1 over the period of 1985–2000 to 24,900 m2·year−1 over the period of 2010–2017. Electromagnetic measurements carried out on the surfaces of the sandurs demonstrated that the electrical resistivity of the ground is high in the apex of the Elveflya fan (ρ ≥ 1 kΩ.m) and low in its toe (typically ρ < 200 Ω.m), as in the case of the Nottingham fan ground. In the interpretation advanced here, permafrost developed in the proximal part of the Elveflya sandur, which continues to be supplied by fresh groundwaters flowing from the glacier direction. Low electrical resistivity of the ground in the distal part of the outwash fan suggests the absence of ground ice in this zone, which is subjected to the intrusion of salty and comparatively warm seawater, reaching approximately 1 km inland under the surface of the low-elevated marine terrace. The identified zones additionally display different tendencies for vertical movements of the terrain surface, as identified with the Small Baseline Subset (SBAS) method. The proximal part of the Elveflya outwash fan is relatively stable, while its distal part lowers in the summer period by a maximum of 5 cm. The resulting morphological changes include linear cracks having lengths up to 580 m and an arc line consistent with the coastline.


RSC Advances ◽  
2014 ◽  
Vol 4 (25) ◽  
pp. 12729-12736 ◽  
Author(s):  
Katarzyna Winkler ◽  
Tomasz Wojciechowski ◽  
Malwina Liszewska ◽  
Ewa Górecka ◽  
Marcin Fiałkowski

We present comprehensive studies of the morphological evolution that gold nanoparticles undergo during their adsorption on a solid substrate and subsequent oxygen plasma treatment.


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