scholarly journals Climate, tectonics or morphology: what signals can we see in drainage basin sediment yields?

2013 ◽  
Vol 1 (1) ◽  
pp. 67-91 ◽  
Author(s):  
T. J. Coulthard ◽  
M. J. Van de Wiel
Keyword(s):  
Sediment Yield ◽  
Drainage Basin ◽  
Sediment Yields ◽  
Internal Storage ◽  
Storage Effects ◽  
Climatic Drivers ◽  
Basin Morphology ◽  
The Impact ◽  
Small Basin

Abstract. Sediment yields from river basins are typically considered to be controlled by tectonic and climatic drivers. However, climate and tectonics can operate simultaneously and the impact of autogenic processes scrambling or shredding these inputs can make it hard to unpick the role of these drivers from the sedimentary record. Thus an understanding of the relative dominance of climate, tectonics or other processes in the output of sediment from a basin is vital. Here, we use a numerical landscape evolution model (CAESAR) to specifically examine the relative impact of climate change, tectonic uplift (instantaneous and gradual) and basin morphology on sediment yield. Unexpectedly, this shows how the sediment signal from significant rates of uplift (10 m instant or 25 mm a−1) is lost due to internal storage effects within even a small basin. However, the signal from modest increases in rainfall magnitude (10–20%) can be seen in increases in sediment yield. In addition, in larger basins, tectonic inputs can be significantly diluted by regular delivery from non-uplifted parts of the basin.

scholarly journals Climate, tectonics or morphology: what signals can we see in drainage basin sediment yields?

2013 ◽  
Vol 1 (1) ◽  
pp. 13-27 ◽  
Author(s):  
T. J. Coulthard ◽  
M. J. Van de Wiel
Keyword(s):  
Sediment Yield ◽  
Drainage Basin ◽  
Sediment Yields ◽  
Internal Storage ◽  
Storage Effects ◽  
Climatic Drivers ◽  
Basin Morphology ◽  
The Impact ◽  
Small Basin

Abstract. Sediment yields from river basins are typically considered to be controlled by tectonic and climatic drivers. However, climate and tectonics can operate simultaneously and the impact of autogenic processes scrambling or shredding these inputs can make it hard to unpick the role of these drivers from the sedimentary record. Thus an understanding of the relative dominance of climate, tectonics or other processes in the output of sediment from a basin is vital. Here, we use a numerical landscape evolution model (CAESAR) to specifically examine the relative impact of climate change, tectonic uplift (instantaneous and gradual) and basin morphology on sediment yield. Unexpectedly, this shows how the sediment signal from significant rates of uplift (10 m instant or 25 mm a−1) may be lost due to internal storage effects within even a small basin. However, the signal from modest increases in rainfall magnitude (10–20%) can be seen in increases in sediment yield. In addition, in larger basins, tectonic inputs can be significantly diluted by regular delivery from non-uplifted parts of the basin.

scholarly journals Impact of climate change on sediment yield in the Mekong River Basin: a case study of the Nam Ou Basin, Lao PDR

2012 ◽  
Vol 9 (3) ◽  
pp. 3339-3384
Author(s):  
B. Shrestha ◽  
M. S. Babel ◽  
S. Maskey ◽  
A. van Griensven ◽  
S. Uhlenbrook ◽  
...  
Keyword(s):  
Climate Change ◽  
Sediment Yield ◽  
Assessment Tool ◽  
Negative Impact ◽  
Lao Pdr ◽  
Sediment Flux ◽  
Monthly Precipitation ◽  
Sediment Yields ◽  
Impact Of Climate Change ◽  
The Impact

Abstract. This paper evaluates the impact of climate change on sediment yield in the Nam Ou Basin located in Northern Laos. The Soil and Water Assessment Tool (SWAT) is used to assess future changes in sediment flux attributable to climate change. Future precipitation and temperature series are constructed through a delta change approach. As per the results, in general, temperature as well as precipitation show increasing trends in both scenarios, A2 and B2. However, monthly precipitation shows both increasing and decreasing trends. The simulation results exhibit that the wet and dry seasonal and annual stream discharges are likely to increase (by up to 15, 17 and 14% under scenario A2; and 11, 5 and 10% under scenario B2 respectively) in the future, which will lead to increased wet and dry seasonal and annual sediment yields (by up to 39, 28 and 36% under scenario A2; and 23, 12 and 22% under scenario B2 respectively). A higher discharge and more sediment flux are expected during the wet seasons, although the changes, percentage-wise, are observed to be higher during the dry months. In conclusion, the sediment yield from the Nam Ou Basin is likely to increase with climate change, which strongly suggests the need for basin-wide sediment management strategies in order to reduce the negative impact of this change.

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.

scholarly journals Using the UKCP09 probabilistic scenarios to model the amplified impact of climate change on drainage basin sediment yield

2012 ◽  
Vol 16 (11) ◽  
pp. 4401-4416 ◽  
Author(s):  
T. J. Coulthard ◽  
J. Ramirez ◽  
H. J. Fowler ◽  
V. Glenis
Keyword(s):  
Climate Change ◽  
Return Period ◽  
Extreme Events ◽  
Sediment Yield ◽  
Drainage Basin ◽  
Climate Change Scenarios ◽  
Hourly Rainfall ◽  
Baseline Values ◽  
The Impact ◽  
Emissions Scenario

Abstract. Precipitation intensities and the frequency of extreme events are projected to increase under climate change. These rainfall changes will lead to increases in the magnitude and frequency of flood events that will, in turn, affect patterns of erosion and deposition within river basins. These geomorphic changes to river systems may affect flood conveyance, infrastructure resilience, channel pattern, and habitat status as well as sediment, nutrient and carbon fluxes. Previous research modelling climatic influences on geomorphic changes has been limited by how climate variability and change are represented by downscaling from global or regional climate models. Furthermore, the non-linearity of the climatic, hydrological and geomorphic systems involved generate large uncertainties at each stage of the modelling process creating an uncertainty "cascade". This study integrates state-of-the-art approaches from the climate change and geomorphic communities to address these issues in a probabilistic modelling study of the Swale catchment, UK. The UKCP09 weather generator is used to simulate hourly rainfall for the baseline and climate change scenarios up to 2099, and used to drive the CAESAR landscape evolution model to simulate geomorphic change. Results show that winter rainfall is projected to increase, with larger increases at the extremes. The impact of the increasing rainfall is amplified through the translation into catchment runoff and in turn sediment yield with a 100% increase in catchment mean sediment yield predicted between the baseline and the 2070–2099 High emissions scenario. Significant increases are shown between all climate change scenarios and baseline values. Analysis of extreme events also shows the amplification effect from rainfall to sediment delivery with even greater amplification associated with higher return period events. Furthermore, for the 2070–2099 High emissions scenario, sediment discharges from 50-yr return period events are predicted to be 5 times larger than baseline values.

scholarly journals Paleo-Drainage Network, Morphotectonics, and Fluvial Terraces: Clues from the Verde Stream in the Middle Sangro River (Central Italy)

Geosciences ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 337 ◽  
Author(s):  
Enrico Miccadei ◽  
Cristiano Carabella ◽  
Giorgio Paglia ◽  
Tommaso Piacentini
Keyword(s):  
Drainage Basin ◽  
Central Italy ◽  
General Setting ◽  
River Valley ◽  
Drainage Network ◽  
Fluvial Terraces ◽  
Field Evidence ◽  
Basin Scale ◽  
The Impact

This work analyzes the role of paleo-drainage network, morphotectonics, and surface processes in landscape evolution in a sector of the transition zone between the chain and the piedmont area of Central Apennines. Particularly, it focuses on the Verde Stream, a tributary of the middle Sangro River valley, which flows in the southeastern Abruzzo area at the boundary with the Molise region. The Verde Stream was investigated through a drainage basin scale geomorphological analysis incorporating the morphometry of the orography and hydrography, structural geomorphological field mapping, and the investigation of morphological field evidence of tectonics with their statistical azimuthal distributions. The local data obtained were compared with the analysis of the middle Sangro River valley and the tectonic features of the Abruzzo–Molise area. This approach led us to also provide relevant clues about the definition of the role of karst features and paleo-landscapes in the general setting of the study area and to identify the impact of active tectonics, confirmed by recent and active seismicity. In conclusion, the paper contributes to defining the main stages of the geomorphological evolution of this area, driven by uplift and local tectonics and due to a combination of fluvial, karst, and landslide processes.

scholarly journals Andean uplift, drainage basin formation, and the evolution of riverweeds (Marathrum, Podostemaceae) in northern South America

2020 ◽  
Author(s):  
Ana M. Bedoya ◽  
Adam D. Leaché ◽  
Richard G. Olmstead
Keyword(s):  
South America ◽  
Landscape Change ◽  
Drainage Basin ◽  
Parental Line ◽  
List Type ◽  
Basin Formation ◽  
Northern South America ◽  
The Impact ◽  
River Drainages

SummaryNorthern South America is a geologically dynamic and species-rich region. While fossil and stratigraphic data show that reconfiguration of river drainages resulted from mountain uplift in the tropical Andes, investigations of the impact of landscape change on the evolution of the flora in the region have been restricted to terrestrial taxa.We explore the role of landscape change on the evolution of plants living strictly in rivers across drainage basins in northern South America by conducting population structure, phylogenomic, phylogenetic networks, and divergence-dating analyses for populations of riverweeds (Marathrum, Podostemaceae).We show that mountain uplift and drainage basin formation isolated populations of Marathrum and created barriers to gene flow across rivers drainages. Sympatric species hybridize and the hybrids show the phenotype of one parental line. We propose that the pattern of divergence of populations reflect the formation of river drainages, which was not complete until <4 MaOur study provides a clear picture of the role of landscape change in shaping the evolution of riverweeds in northern South America, advances our understanding of the reproductive biology of this remarkable group of plants, and spotlights the impact of hybridization in phylogenetic inference.

scholarly journals Evaluation of sediment yield predicting models of Ghana

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
John Manyimadin Kusimi ◽  
Bertha Ansaah Kusimi ◽  
Barnabas A. Amisigo
Keyword(s):  
Suspended Sediment ◽  
River Basin ◽  
Sediment Yield ◽  
Water Resource Management ◽  
Drainage Basin ◽  
Suspended Sediments ◽  
Yield Data ◽  
Sediment Yields ◽  
Alternative Approach ◽  
Pra River

Fluvial sediment transport data is a very important data for effective water resource management. However, acquiring this data is expensive and tedious hence sediment yield modeling has become an alternative approach in estimating river sediment yields. In Ghana, several sediment yield predicting models have been developed to estimate the sediment yields of ungauged rivers including the Pra River Basin. In this paper, 10 months sediment yield data of the Pra River Basin was used to evaluate the existing sediment yield predicting models of Ghana. A regression analysis between predicted sediment yield data derived from the models and the observed suspended sediment yields of the Pra Basin was done to determine the extent of estimation of observed sediment yields. The prediction of suspended sediment yield was done for 4 out of 5 existing sediment yield predicting models in Ghana. There were variations in sediment yield between observed and predicted suspended sediments. All predicted sediment yields were lower than observed data except for equation 3 where the results were mixed. All models were found to be good estimators of fluvial sediments with the best model being equation 4. Sediment yield tends to increase with drainage basin area. 

scholarly journals Impact on sediment yield due to the intensification of tobacco production in a catchment in Southern Brazil

2006 ◽  
Vol 36 (2) ◽  
pp. 669-672 ◽  
Author(s):  
Gustavo Henrique Merten ◽  
Jean Paolo Gomes Minella
Keyword(s):  
Sediment Yield ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Flow Rates ◽  
Profound Impact ◽  
Sediment Yields ◽  
Tobacco Production ◽  
Tobacco Cultivation ◽  
The Impact ◽  
Rural Catchment

Tobacco production in Southern Brazil has caused a profound impact in the environment, resulting in heavy sediment yields and diminishing water quality. Public programmes have attempted to address these problems by encouraging the implementation of erosion control practices. To evaluate the impact of these programmes, a small rural catchment (1.33km²) in Arvorezinha county, in the state of Rio Grande do Sul, Brazil, has been monitored since 2001. Instruments to automatically monitor flow rate and precipitation were installed in the catchment and sediment has been measured manually using a DH-48 sampler. Despite lower rainfall in 2003, there was a significant increase in the frequency of low and average flow rates, and sediment yield increased 25% in 2003 (91Mg km-2 year-1), compared with 2002 (73Mg km-2 year-1). These results can be explained by a 37.7% increase in the area dedicated to tobacco cultivation in 2003, due to a rise in tobacco prices.

scholarly journals Analysis of state of biotic resources of Vereshchytsia River basin

2014 ◽  
pp. 88-97
Author(s):  
Volodymyr Grekh ◽  
Oksana Kormylo ◽  
Semen Kukurudza
Keyword(s):  
Key Words ◽  
River Basin ◽  
Drainage Basin ◽  
Anthropogenic Factors ◽  
Rational Use ◽  
Forage Base ◽  
The Impact ◽  
Hunting And Fishing ◽  
Biotic Resources

The resources of plants (forest and meadow-marsh), animals (hunting and fishing) on example of the drainage basin of river Vereshchytsia as clearly defined the terrestrial-waterу spatio-functional geosystem are analysed. Also the role of phyto- and zooplankton in the improving of the forage base fisheries is analysed. The relationships and the interdependences of abiotic and biotic components of the environment and the impact of the anthropogenic factors on them are considered. Key words: biotic resources, drainage basin, river basin approach, rational use, reproduction, protection of biota.

Intergroup Threat and Outgroup Attitudes

2013 ◽  
Vol 44 (5) ◽  
pp. 311-319 ◽  
Author(s):  
Marco Brambilla ◽  
David A. Butz
Keyword(s):  
Gay Men ◽  
Social Group ◽  
Welfare Recipients ◽  
Intergroup Attitudes ◽  
Social Policies ◽  
Intergroup Threat ◽  
Economic Threat ◽  
The Impact ◽  
General Climate

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.

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