Distribution of fluvial sediment yields in hyper-arid areas, exemplified by Nahal Nehushtan, Israel 

2021 ◽  
Author(s):  
Rachel Armoza-Zvuloni ◽  
Yanai Shlomi ◽  
Itay Abadi ◽  
Rachamim Shem-Tov ◽  
Jonathan B. Laronne
Keyword(s):  
Sediment Yield ◽  
Flash Flood ◽  
Flood Frequency ◽  
Drainage Area ◽  
Stratigraphic Correlation ◽  
Rain Event ◽  
Arid Environments ◽  
Arid Areas ◽  
Fluvial Sediment ◽  
Sediment Yields

<p>Floods rarely occur in hyper-arid deserts and little is known about the magnitude and frequency of sediment delivery from their basins, despite their importance to changes to the landscape as well as to infrastructures and engineering activities. Sediment yield from the Nahal Nehushtan watershed (15.7 km<sup>2</sup>) located in the Timna Valley in southern Israel, was determined by assessing stratigraphic sections in its 60-year reservoir deposits. Stratigraphic correlation between event couplets allowed quantification of sediment yields representing 13 former flash-flood events. Based on the sediment volume in the reservoir, the 24.6 t km<sup>-2</sup> y<sup>-1</sup> average sediment yield is the lowest among other studied warm deserts. Among the event layers, five are voluminously small and seven are medium-sized. The thickest layer, deposited by a flash flood caused by a single short rain event, contributed 29% of the total sediment yield. This demonstrates the overarching effect of medium magnitude events on the rate of sediment production in a hyper-arid setting. Based on event reservoir sedimentation from watersheds located in several hyper-arid areas in the Middle East and North America, sediment load increases with drainage area as expected; however, sediment yield does not decrease with drainage area, as was shown for arid environments. Overall, mean annual sediment yield is very low and increases with flood frequency, with considerable variation generated by local characteristics. Our quantitative results together with previous studies of hyper-arid areas, provide complementary evidence of fluvial sediment transport - the main landscape designer in fluvial desert landscapes.</p>

scholarly journals Prioritization of Sub-Watersheds to Sediment Yield and Evaluation of Best Management Practices in Highland Ethiopia, Finchaa Catchment

Land ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 650
Author(s):  
Wakjira Takala Dibaba ◽  
Tamene Adugna Demissie ◽  
Konrad Miegel
Keyword(s):  
Soil Erosion ◽  
Best Management Practices ◽  
Sediment Yield ◽  
Soil Loss ◽  
Crop Production ◽  
Management Practices ◽  
Assessment Tool ◽  
Swat Model ◽  
Sediment Yields ◽  
Soil And Water

Excessive soil loss and sediment yield in the highlands of Ethiopia are the primary factors that accelerate the decline of land productivity, water resources, operation and function of existing water infrastructure, as well as soil and water management practices. This study was conducted at Finchaa catchment in the Upper Blue Nile basin of Ethiopia to estimate the rate of soil erosion and sediment loss and prioritize the most sensitive sub-watersheds using the Soil and Water Assessment Tool (SWAT) model. The SWAT model was calibrated and validated using the observed streamflow and sediment data. The average annual sediment yield (SY) in Finchaa catchment for the period 1990–2015 was 36.47 ton ha−1 yr−1 with the annual yield varying from negligible to about 107.2 ton ha−1 yr−1. Five sub-basins which account for about 24.83% of the area were predicted to suffer severely from soil erosion risks, with SY in excess of 50 ton ha−1 yr−1. Only 15.05% of the area within the tolerable rate of loss (below 11 ton ha−1yr−1) was considered as the least prioritized areas for maintenance of crop production. Despite the reasonable reduction of sediment yields by the management scenarios, the reduction by contour farming, slope terracing, zero free grazing and reforestation were still above the tolerable soil loss. Vegetative contour strips and soil bund were significant in reducing SY below the tolerable soil loss, which is equivalent to 63.9% and 64.8% reduction, respectively. In general, effective and sustainable soil erosion management requires not only prioritizations of the erosion hotspots but also prioritizations of the most effective management practices. We believe that the results provided new and updated insights that enable a proactive approach to preserve the soil and reduce land degradation risks that could allow resource regeneration.

scholarly journals Volumetric Quantification of Flash Flood Using Microwave Data on a Watershed Scale in Arid Environments, Saudi Arabia

2021 ◽  
Vol 13 (8) ◽  
pp. 4115
Author(s):  
Jaka Budiman ◽  
Jarbou Bahrawi ◽  
Asep Hidayatulloh ◽  
Mansour Almazroui ◽  
Mohamed Elhag
Keyword(s):  
Saudi Arabia ◽  
Flash Flood ◽  
Remote Sensing Data ◽  
Surface Elevation ◽  
Flood Mapping ◽  
Depth Information ◽  
Arid Environments ◽  
Volume Calculation ◽  
Flood Depth ◽  
Flood Volume

Actual flood mapping and quantification in an area provide valuable information for the stakeholder to prevent future losses. This study presents the actual flash flood quantification in Al-Lith Watershed, Saudi Arabia. The study is divided into two steps: first is actual flood mapping using remote sensing data, and the second is the flood volume calculation. Two Sentinel-1 images are processed to map the actual flood, i.e., image from 25 May 2018 (dry condition), and 24 November 2018 (peak flood condition). SNAP software is used for the flood mapping step. During SNAP processing, selecting the backscatter data representing the actual flood in an arid region is challenging. The dB range value from 7.23–14.22 is believed to represent the flood. In GIS software, the flood map result is converted into polygon to define the flood boundary. The flood boundary that is overlaid with Digital Elevation Map (DEM) is filled with the same elevation value. The Focal Statistics neighborhood method with three iterations is used to generate the flood surface elevation inside the flood boundary. The raster contains depth information is derived by subtraction of the flood surface elevation with DEM. Several steps are carried out to minimize the overcalculation outside the flood boundary. The flood volume can be derived by the multiplication of flood depth points with each cell size area. The flash flood volume in Al-Lith Watershed on 24 November 2018 is 155,507,439 m3. Validity checks are performed by comparing it with other studies, and the result shows that the number is reliable.

Runoff and sediment yield from snowmelt and rainfall as influenced by forage type and grazing intensity

1998 ◽  
Vol 78 (4) ◽  
pp. 699-706 ◽  
Author(s):  
S. I. Gill ◽  
M. A. Naeth ◽  
D. S. Chanasyk ◽  
V. S. Baron
Keyword(s):  
Sediment Yield ◽  
Environmental Sustainability ◽  
Grazing Intensity ◽  
Annual Runoff ◽  
Rainfall Simulation ◽  
Sediment Yields ◽  
Natural Rainfall ◽  
Grazing Intensities ◽  
Grazing Systems ◽  
Runoff And Sediment Yield

Currently, there is interest in Western Canada in extending the grazing season using perennial and annual forages. Of greatest concern is the environmental sustainability of these grazing systems, with emphasis on their ability to withstand erosion. A study to examine the runoff and sediment yields of annual and perennial forages in central Alberta was initiated in 1994. Runoff and sediment yield were quantified under snowmelt and rainfall events for two seasons. Rainfall simulation was used to further examine runoff under growing season conditions. Four forage treatments (two annuals: triticale and a barley/triticale mixture and two perennials: smooth bromegrass and meadow bromegrass) and three grazing intensities (light, medium and heavy) were studied, each replicated four times. Total annual runoff was dominated by snowmelt. Generally runoff volumes, sediment yields, sediment ratios and runoff coefficients were all low. Bare ground increased with increasing grazing intensity and was significantly greater in annuals than perennials for all grazing intensities. Litter biomass decreased with increasing grazing intensity and was generally similar in all species for both years at heavy and medium grazing intensities. Results from the rainfall simulation corroborated those under natural rainfall conditions and generally indicated the sustainability of these grazing systems at this site. Key words: Forages, soil erosion, sustainability, rainfall simulation

Using convection-permitting climate models and a high-resolution distributed hydrological model to assess future changes in Alpine flash floods.

2021 ◽  
Author(s):  
Marjanne Zander ◽  
Pety Viguurs ◽  
Frederiek Sperna Weiland ◽  
Albrecht Weerts
Keyword(s):  
High Resolution ◽  
Natural Hazards ◽  
Climate Models ◽  
Flash Flood ◽  
Regional Climate ◽  
Flash Floods ◽  
Flood Frequency ◽  
Climate Dynamics ◽  
Future Climate ◽  
European Climate

<p>Flash Floods are damaging natural hazards which often occur in the European Alps. Precipitation patterns and intensity may change in a future climate affecting their occurrence and magnitude. For impact studies, flash floods can be difficult to simulate due the complex orography and limited extent & duration of the heavy rainfall events which trigger them. The new generation convection-permitting regional climate models improve the intensity and frequency of heavy precipitation (Ban et al., 2021).</p><p>Therefore, this study combines such simulations with high-resolution distributed hydrological modelling to assess changes in flash flood frequency and occurrence over the Alpine terrain. We use the state-of-the-art Unified Model (Berthou et al., 2018) to drive a high-resolution distributed hydrological wflow_sbm model (e.g. Imhoff et al., 2020) covering most of the Alpine mountain range on an hourly resolution. Simulations of the future climate RCP 8.5 for the end-of-century (2096-2105) and current climate (1998-2007) are compared.</p><p>First, the wflow_sbm model was validated by comparing ERA5 driven simulation with streamflow observations (across Rhone, Rhine, Po, Adige and Danube). Second, the wflow_sbm simulation driven by UM simulation of the current climate was compared to a dataset of historical flood occurrences (Paprotny et al., 2018, Earth Syst. Sci. Data) to validate if the model can accurately simulate the location of the flash floods and to determine a suitable threshold for flash flooding. Finally, the future run was used to asses changes in flash flood frequency and occurrence. Results show an increase in flash flood frequency for the Upper Rhine and Adige catchments. For the Rhone the increase was less pronounced. The locations where the flash floods occur did not change much.</p><p>This research is embedded in the EU H2020 project EUCP (EUropean Climate Prediction system) (https://www.eucp-project.eu/), which aims to support climate adaptation and mitigation decisions for the coming decades by developing a regional climate prediction and projection system based on high-resolution climate models for Europe.</p><p> </p><p>N. Ban, E. Brisson, C. Caillaud, E. Coppola, E. Pichelli, S. Sobolowski, …, M.J. Zander (2021): “The first multi-model ensemble of regional climate simulations at the kilometer-scale resolution, Part I: Evaluation of precipitation”, manuscript accepted for publication in Climate Dynamics.</p><p>S. Berthou, E.J. Kendon, S. C. Chan, N. Ban, D. Leutwyler, C. Schär, and G. Fosser, 2018, “Pan-european climate at convection-permitting scale: a model intercomparison study.” Climate Dynamics, pages 1–25, DOI: 10.1007/s00382-018-4114-6</p><p>Imhoff, R.O., W. van Verseveld, B. van Osnabrugge, A.H. Weerts, 2020. “Scaling point-scale pedotransfer functions parameter estimates for seamless large-domain high-resolution distributed hydrological modelling: An example for the Rhine river.” Water Resources Research, 56. Doi: 10.1029/2019WR026807</p><p>Paprotny, D., Morales Napoles, O., & Jonkman, S. N., 2018. "HANZE: a pan-European database of exposure to natural hazards and damaging historical floods since 1870". Earth System Science Data, 10, 565–581, https://doi.org/10.5194/essd-10-565-2018</p>

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 Effect of natural rainfall on the migration characteristics of runoff and sediment on purple soil sloping cropland during different planting stages

2021 ◽  
Author(s):  
Yi Wang ◽  
Jiupai Ni ◽  
Chengsheng Ni ◽  
Sheng Wang ◽  
Deti Xie
Keyword(s):  
Sediment Yield ◽  
Soil Loss ◽  
Heavy Rain ◽  
Sediment Concentration ◽  
Purple Soil ◽  
Torrential Rain ◽  
Sediment Yields ◽  
Natural Rainfall ◽  
Sediment Loss ◽  
Rain Events

Abstract Due to the difficulty in monitoring subsurface runoff and sediment migration, their loss loads are still not clear and need further study. This study monitored water and soil loss occurring within experimental field plots for two calendar years under natural rainfall events. The sediment loss load was quantified by considering the corresponding water flow flux and its sediment concentration. The results showed that 60.04% of the runoff and 2.83% of the sediment were lost underground. The annual underground sediment loss reached up to 54.6 kg*ha−1*yr−1. A total of 69.68% of the runoff yield and 67.25% of the sediment yield were produced during the corn planting stage (CPS: March–July). Heavy rain and torrential rain events produced 94.45%, 65.46% of the annual runoff and 94.45%, 76.21% of the sediment yields during the corn-planting stage and summer fallow period (SFP: August–September). The rain frequency, rainfall, and rainfall duration of each planting stage significantly affected the resulting runoff and sediment yield. Measures aimed at the prevention and control of water-soil loss from purple soil sloping land should heavily focus on torrential rain and heavy rain events during the CPS and SFP. This paper aims to provide a practical reference for quantifying the water and soil loss from purple soil sloping cropland.

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 Livestock redistribute runoff and sediments in semi-arid rangeland areas

Solid Earth ◽  
2015 ◽  
Vol 6 (2) ◽  
pp. 433-443 ◽  
Author(s):  
P. Sarah ◽  
M. Zonana
Keyword(s):  
Sediment Yield ◽  
Overland Flow ◽  
Arid Areas ◽  
Mosaic Pattern ◽  
Two Phase ◽  
Surface Patches ◽  
Sediment Deposits ◽  
Three Phase ◽  
Almost All ◽  
Semi Arid

Abstract. Semi-arid areas where grazing is the main land use exhibit a "three-phase-mosaic" pattern of dominant surface patches: shrubs, trampling routes, and intershrub areas. This pattern differs from the "two-phase mosaic" seen in grazing-free semi-arid areas. The patches might create a positive feedback process in which enhanced infiltration beneath shrubs minimizes overland flow from under their canopies, thereby strengthening the sink–source mechanism by which overland flow generated between shrubs rapidly infiltrates into the soil beneath them, where it deposits soil particles, litter, nutrients and organic matter, thereby enhancing infiltration by changing the local microtopography, and improving soil properties. To analyze sink–source relationships among the patches in grazed areas in rangelands of the semi-arid northern Negev region of Israel, we constructed small runoff plots, 0.25–1.0 m2 in area, of five types: shrub (Sarcopoterium spinosum), intershrub, route, route–shrub combination, and intershrub–shrub combination. The shrubs always occupied the downslope part of the plot. Overland flow and sediment deposits were measured in all plots during 2007/8 and 2008/9. The combined plots yielded much less overland flow and sediments than intershrub, routes and shrub ones, indicating that the shrubs absorbed almost all the yields of the upper part of their plots. The shrubs generated less runoff and sediments than routes and intershrubs; runoff flows from the routes and intershrubs were similar; sediment yield was highest in the intershrubs. Thus, runoff yield exhibited a two-phase mosaic pattern, and sediment yield, i.e., soil erosion, a three-phase mosaic pattern.

scholarly journals Sediment Load and Suspended Sediment Concentration Prediction

2013 ◽  
Vol 1 (No. 1) ◽  
pp. 23-31 ◽  
Author(s):  
Bečvář Martin
Keyword(s):  
Suspended Sediment ◽  
Sediment Yield ◽  
Suspended Sediment Concentration ◽  
Sediment Load ◽  
Sediment Concentration ◽  
River Basins ◽  
River Systems ◽  
Sediment Yields ◽  
Suspended Sediment Concentrations ◽  
Annual Sediment

Sediment is a natural component of riverine environments and its presence in river systems is essential. However, in many ways and many places river systems and the landscape have been strongly affected by human activities which have destroyed naturally balanced sediment supply and sediment transport within catchments. As a consequence a number of severe environmental problems and failures have been identified, in particular the link between sediments and chemicals is crucial and has become a subject of major scientific interest. Sediment load and sediment concentration are therefore highly important variables that may play a key role in environment quality assessment and help to evaluate the extent of potential adverse impacts. This paper introduces a methodology to predict sediment loads and suspended sediment concentrations (SSC) in large European river basins. The methodology was developed within an MSc research study that was conducted in order to improve sediment modelling in the GREAT-ER point source pollution river modelling package. Currently GREAT-ER uses suspended sediment concentration of 15 mg/l for all rivers in Europe which is an obvious oversimplification. The basic principle of the methodology to predict sediment concentration is to estimate annual sediment load at the point of interest and the amount of water that transports it. The amount of transported material is then redistributed in that corresponding water volume (using the flow characteristic) which determines sediment concentrations. Across the continent, 44 river basins belonging to major European rivers were investigated. Suspended sediment concentration data were collected from various European basins in order to obtain observed sediment yields. These were then compared against the traditional empiric sediment yield estimators. Three good approaches for sediment yield prediction were introduced based on the comparison. The three approaches were applied to predict annual sediment yields which were consequently translated into suspended sediment concentrations. SSC were predicted at 47 locations widely distributed around Europe. The verification of the methodology was carried out using data from the Czech Republic. Observed SSC were compared against the predicted ones which validated the methodology for SSC prediction.

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