scholarly journals Geomorphic Approaches to Estimate Short-Term Erosion Rates: An Example from Valmarecchia River System (Northern Apennines, Italy)

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2535
Author(s):  
Veronica Guerra ◽  
Maurizio Lazzari
Keyword(s):  
Drainage Basin ◽  
Regional Scale ◽  
River System ◽  
Northern Apennines ◽  
Short Term ◽  
Catchment Basin ◽  
Average Value ◽  
Erosion Rates ◽  
Fluvial Dynamics ◽  
Uplift Rates

Studying fluvial dynamics and environments, GIS-based analyses are of fundamental importance to evaluate the network geometry and possible anomalies, and can be particularly useful to estimate modifications in processes and erosion rates. The aim of this paper is to estimate short-term erosion rates attributable to fluvial processes in two sample catchment sub-basins of the Marecchia river valley, by conducting quantitative morphometric analyses in order to calculate various descriptive parameters of the hierarchisation of the river networks and the mean turbid transport of streams (Tu). Sediment yield transported by streams can in fact partially express the amount of erosional processes acting within the drainage basin. The study area includes two sub-basins of the Marecchia valley (Senatello river, 49 km2 and Mazzocco river, 47 km2), chosen because of their similar extent and of the different location in the major catchment basin. Starting from geomorphological maps of the two river basins, the Tu parameter has been calculated and converted in short-term rate (average value 0.21 mm/year). Moreover, the comparison of these short-term mean data with the uplift rates calculated on a regional scale (0.41 ± 0.26 mm/year) in the Marecchia valley confirms that the northern Apennines may represent a non-steady state system.

scholarly journals Extracting information on the spatial variability in erosion rate stored in detrital cooling age distributions in river sands

2017 ◽  
Author(s):  
Jean Braun ◽  
Lorenzo Gemignani ◽  
Peter van der Beek
Keyword(s):  
Steady State ◽  
Spatial Variability ◽  
Erosion Rate ◽  
Regional Scale ◽  
River System ◽  
Eastern Himalaya ◽  
Relative Distribution ◽  
Simple Method ◽  
Erosion Rates ◽  
Mountain Belts

Abstract. The purpose of detrital thermochronology is to provide constraints on regional scale exhumation rate and its spatial variability in actively eroding mountain ranges. Procedures that use cooling age distributions coupled with hypsometry and thermal models have been developed in order to extract quantitative estimates of erosion rate and its spatial distribution, assuming steady state between tectonic uplift and erosion. This hypothesis precludes the use of these procedures to assess the likely transient response of mountain belts to changes in tectonic or climatic forcing. In this paper, we describe a simple method that, using the observed detrital mineral age distributions collected in a system of river catchments, allows to extract information about the relative distribution of erosion rates in an eroding hinterland without relying on a steady-state assumption or the value of thermal parameters. The model is based on a relatively low number of parameters describing lithological variability among the various catchments and their sizes, and only uses the raw binned ages. In order to illustrate the method, we invert age distributions collected in the Eastern Himalaya, one of the most tectonically active places on Earth. From the inversion of the cooling age distributions we predict present day erosion rates of the catchments along the Siang-Tsangpo-Brahmaputra river system, as well as smaller tributaries. We show that detrital age distributions contain dual information about present-day erosion rate, i.e. from the predicted distribution of surface ages within each catchment and from the relative contribution of any given catchment to the river distribution. The inversion additionally allows comparing modern erosion rates to long-term exhumation rates. We provide a simple implementation of the method in R.code within a Jupyter Notebook that includes the data used in this paper for illustration purposes.

scholarly journals Long-term geomorphological evolution of the axial zone of the Campania-Lucania Apennine, southern Italy: a review

2017 ◽  
Vol 68 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Marcello Schiattarella ◽  
Salvatore Ivo Giano ◽  
Dario Gioia
Keyword(s):  
Southern Italy ◽  
Morphological Evolution ◽  
Structural Data ◽  
Middle Pleistocene ◽  
Southern Apennines ◽  
Axial Zone ◽  
Entire Study ◽  
Erosion Rates ◽  
Uplift Rates ◽  
Land Surfaces

Abstract Uplift and erosion rates have been calculated for a large sector of the Campania-Lucania Apennine and Calabrian arc, Italy, using both geomorphological observations (elevations, ages and arrangement of depositional and erosional land surfaces and other morphotectonic markers) and stratigraphical and structural data (sea-level related facies, base levels, fault kinematics, and fault offset estimations). The values of the Quaternary uplift rates of the southern Apennines vary from 0.2 mm/yr to about 1.2–1.3 mm/yr. The erosion rates from key-areas of the southern Apennines, obtained from both quantitative geomorphic analysis and missing volumes calculations, has been estimated at 0.2 mm/yr since the Middle Pleistocene. Since the Late Pleistocene erosion and uplift rates match well, the axial-zone landscape could have reached a flux steady state during that time, although it is more probable that the entire study area may be a transient landscape. Tectonic denudation phenomena — leading to the exhumation of the Mesozoic core of the chain — followed by an impressive regional planation started in the Late Pliocene have to be taken into account for a coherent explanation of the morphological evolution of southern Italy.

Accelerated Erosion and Sedimentation in Southeast Asia

2005 ◽  
Author(s):  
Avijit Gupta
Keyword(s):  
Southeast Asia ◽  
Sediment Yield ◽  
Large Scale ◽  
Drainage Basin ◽  
High Rate ◽  
Annual Rainfall ◽  
Sediment Yields ◽  
Erosion Rates ◽  
Sediment Transfer ◽  
Very High

Periodic attempts to plot global distribution of erosion and sedimentation usually attribute most of Southeast Asia with a very high sediment yield (Milliman and Meade 1983). The erosion rates and sediment yield figures are especially high for maritime Southeast Asia. Milliman and Syvitski (1992), for example, listed 3000 t km−2 yr−1 for the archipelagos and peninsulas of Southeast Asia. They provided a number of natural explanations for the high erosion rate: location near active plate margins, pyroclastic eruptions, steep slopes, and mass movements. This is also a region with considerable annual rainfall, a very substantial percentage of which tends to be concentrated in a few months and falls with high intensity. Part of Southeast Asia (the Philippines, Viet Nam, Timor) is visited by tropical cyclones with heavy, intense rainfall and possible associated wind damage to existing vegetation. The fans at the foot of slopes, the large volume of sediment stored in the channel and floodplain of the rivers, and the size of deltas all indicate a high rate of erosion and episodic sediment transfer. This episodic erosion and sediment transfer used to be controlled for most of the region by the thick cover of vegetation that once masked the slopes. When vegetation is removed soil and regolith de-structured, and natural slopes altered, the erosion rates and sediment yield reach high figures. Parts of Southeast Asia display striking anthropogenic alteration of the landscape, although the resulting accelerated erosion may be only temporary, operating on a scale of several years. Over time the affected zones shift, and slugs of sediment continue to arrive in a river but from different parts of its drainage basin. The combination of anthropogenic alteration and fragile landforms may give rise to very high local yields. Sediment yields of more than 15 000 t km−2 yr−1 have been estimated from such areas (Ruslan and Menam, cited in Lal 1987). This is undoubtedly towards the upper extreme, but current destruction of the vegetation cover due to deforestation, expansion of agriculture, mining, urbanization, and implementation of large-scale resettlement schemes has increased the sediment yield from < 102 to > 103 t km−2 yr−1.

Chamber for controlling end-tidal gas tensions over sustained periods in humans

1995 ◽  
Vol 78 (3) ◽  
pp. 1088-1091 ◽  
Author(s):  
L. S. Howard ◽  
R. A. Barson ◽  
B. P. Howse ◽  
T. R. McGill ◽  
M. E. McIntyre ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Feedback Mechanism ◽  
Gas Composition ◽  
Short Term ◽  
Average Value ◽  
Nasal Catheter ◽  
End Tidal

Although techniques for the short-term control of end-tidal gases exist, the lack of a satisfactory technique for longer-term control of the end-tidal gases has limited protracted physiological experiments of this nature. We have constructed a chamber in which subjects can be comfortable for many hours while having their end-tidal gas composition monitored and controlled. The system for controlling the end-tidal gas composition is based on a principle described by Swanson and Bellville (J. Appl. Physiol. 39: 377–385, 1975) in which end-tidal PO2 (PETO2) and PCO2 (PETCO2) are monitored and deviations of the actual PETO2 and PETCO2 (PETCO2) are monitored and deviations of the actual PETO2 and PETCO2 from the desired values are corrected by a feedback mechanism that adjusts the inspired gas composition accordingly. End-tidal and inspired gas tensions are measured via a nasal catheter connected to a mass spectrometer. A computer averages the end-tidal and inspired gas tensions and, at 5-min intervals, adjusts the gas composition inside the chamber. During 8 h of isocapnic hypoxia, the system held the 5-min average value for PETO2 within 2 Torr of the desired value (55 Torr) and the value for PETCO2 within 0.35 Torr of the desired value (the resting value for each subject) in four subjects.

scholarly journals Lithological control on the landscape form of the upper Rhône Basin, Central Swiss Alps

2016 ◽  
Vol 4 (1) ◽  
pp. 253-272 ◽  
Author(s):  
Laura Stutenbecker ◽  
Anna Costa ◽  
Fritz Schlunegger
Keyword(s):  
Swiss Alps ◽  
Short Term ◽  
Linear Discriminant ◽  
Erosion Rates ◽  
Digital Elevation ◽  
Discriminant Analyses ◽  
Controlling Variables ◽  
Uplift And Erosion ◽  
Landscape Morphology

Abstract. The development of topography depends mainly on the interplay between uplift and erosion. These processes are controlled by various factors including climate, glaciers, lithology, seismic activity and short-term variables, such as anthropogenic impact. Many studies in orogens all over the world have shown how these controlling variables may affect the landscape's topography. In particular, it has been hypothesized that lithology exerts a dominant control on erosion rates and landscape morphology. However, clear demonstrations of this influence are rare and difficult to disentangle from the overprint of other signals such as climate or tectonics. In this study we focus on the upper Rhône Basin situated in the Central Swiss Alps in order to explore the relation between topography, possible controlling variables and lithology in particular. The Rhône Basin has been affected by spatially variable uplift, high orographically driven rainfalls and multiple glaciations. Furthermore, lithology and erodibility vary substantially within the basin. Thanks to high-resolution geological, climatic and topographic data, the Rhône Basin is a suitable laboratory to explore these complexities. Elevation, relief, slope and hypsometric data as well as river profile information from digital elevation models are used to characterize the landscape's topography of around 50 tributary basins. Additionally, uplift over different timescales, glacial inheritance, precipitation patterns and erodibility of the underlying bedrock are quantified for each basin. Results show that the chosen topographic and controlling variables vary remarkably between different tributary basins. We investigate the link between observed topographic differences and the possible controlling variables through statistical analyses. Variations of elevation, slope and relief seem to be linked to differences in long-term uplift rate, whereas elevation distributions (hypsometry) and river profile shapes may be related to glacial imprint. This confirms that the landscape of the Rhône Basin has been highly preconditioned by (past) uplift and glaciation. Linear discriminant analyses (LDAs), however, suggest a stronger link between observed topographic variations and differences in erodibility. We therefore conclude that despite evident glacial and tectonic conditioning, a lithologic control is still preserved and measurable in the landscape of the Rhône tributary basins.

A Study of the Column Methane Short-Term Variability in the Atmosphere on a Regional Scale

2018 ◽  
Vol 54 (6) ◽  
pp. 558-569 ◽  
Author(s):  
M. V. Cherepova ◽  
S. P. Smyshlyaev ◽  
M. V. Makarova ◽  
Yu. M. Timofeyev ◽  
A. V. Poberovskiy ◽  
...  
Keyword(s):  
Regional Scale ◽  
Short Term ◽  
Short Term Variability

Was There a Pliocene-Pleistocene Fluvial-Lacustrine Connection between Death Valley and the Colorado River?

1995 ◽  
Vol 43 (3) ◽  
pp. 286-296 ◽  
Author(s):  
William J. Brown ◽  
Michael R. Rosen
Keyword(s):  
Colorado River ◽  
Drainage Basin ◽  
River System ◽  
Turn Of The Century ◽  
Death Valley ◽  
Hydrologic Systems ◽  
Dry Lake ◽  
Middle Pliocene ◽  
River Drainage Basin ◽  
Lake Basins

AbstractSince the turn of the century, a Pliocene-Pleistocene connection between the Death Valley-Owens River pluvial system and the Colorado River drainage basin has been frequently postulated. The two most commonly proposed routes involve (1) a southward overflow from the Death Valley Lake system or (2) southward migration of the Mojave River between its present course and a more southerly route. Under the present topographic regime, a Death Valley Lake capable of overflowing the bedrock saddle at Ludlow, California and discharging southward into the Bristol, Cadiz, and Danby Lake basins (and eventually the Colorado River) would be over 12,000 km2 in size. Few surface and subsurface indicators exist to support either a fluvial or lacustrine connection. Evidence from deep cores and boreholes drilled in Soda, Bristol, Cadiz, and Danby dry lake basins indicate that a hydrologic connection has not occurred during the past 4 myr. No well-documented paleoshoreline features have been located at elevations corresponding to the above hydrologic systems in Death Valley, Silver-Soda, Bristol, or Danby Lake basins. In the Cadiz, Silurian, and Broadwell basins these features have not been found at all. Therefore, we conclude that a hydrologic connection between the Death Valley-Owens River system and the Colorado River has not occurred along either of these routes since the middle Pliocene.

scholarly journals Modelling of marine ecosystem in regional scale for short term prediction of satellite-aided operational fishery advisories

2019 ◽  
Vol 12 (sup2) ◽  
pp. S157-S175
Author(s):  
Kunal Chakraborty ◽  
Sourav Maity ◽  
Aneesh A. Lotliker ◽  
Alakes Samanta ◽  
Jayashree Ghosh ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
Regional Scale ◽  
Short Term ◽  
Term Prediction ◽  
Short Term Prediction
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