scholarly journals Contrasting watershed-scale trends in runoff and sediment yield complicate rangeland water resources planning

2016 ◽  
Author(s):  
M. D. Berg ◽  
F. Marcantonio ◽  
M. A. Allison ◽  
J. McAlister ◽  
B. P. Wilcox ◽  
...  
Keyword(s):  
Sediment Yield ◽  
Land Surface ◽  
Sediment Cores ◽  
Watershed Scale ◽  
Landscape Changes ◽  
Sediment Yields ◽  
Dynamic Landscape ◽  
Cesium 137 ◽  
Lead 210 ◽  
Runoff And Sediment Yield

Abstract. Rangelands cover a large portion of the earth’s land surface and are undergoing dramatic landscape changes. At the same time, these ecosystems face increasing expectations to meet growing water supply needs. To address major gaps in our understanding of rangeland hydrologic function, we investigated historical watershed-scale runoff and sediment yield in a dynamic landscape in central Texas, USA. We quantified the relationship between precipitation and runoff and analyzed reservoir sediment cores dated using Cesium-137 and Lead-210 radioisotopes. Local rainfall and streamflow showed no directional trend over a period of 85 years, resulting in a rainfall-runoff ratio that has been resilient to watershed changes. Reservoir sedimentation rates generally were higher before 1963, but have been much lower and very stable since that time. Our findings suggest that (1) rangeland water yields may be stable over long periods despite dramatic landscape changes while (2) these same landscape changes influence sediment yields that impact downstream reservoir storage. Relying on rangelands to meet water needs demands an understanding of how these dynamic landscapes function and a quantification of the physical processes at work.

scholarly journals Contrasting watershed-scale trends in runoff and sediment yield complicate rangeland water resources planning

2016 ◽  
Vol 20 (6) ◽  
pp. 2295-2307 ◽  
Author(s):  
Matthew D. Berg ◽  
Franco Marcantonio ◽  
Mead A. Allison ◽  
Jason McAlister ◽  
Bradford P. Wilcox ◽  
...  
Keyword(s):  
Sediment Yield ◽  
Land Surface ◽  
Sediment Cores ◽  
Watershed Scale ◽  
Landscape Changes ◽  
Sediment Yields ◽  
Dynamic Landscape ◽  
Cesium 137 ◽  
Lead 210 ◽  
Runoff And Sediment Yield

Abstract. Rangelands cover a large portion of the earth's land surface and are undergoing dramatic landscape changes. At the same time, these ecosystems face increasing expectations to meet growing water supply needs. To address major gaps in our understanding of rangeland hydrologic function, we investigated historical watershed-scale runoff and sediment yield in a dynamic landscape in central Texas, USA. We quantified the relationship between precipitation and runoff and analyzed reservoir sediment cores dated using cesium-137 and lead-210 radioisotopes. Local rainfall and streamflow showed no directional trend over a period of 85 years, resulting in a rainfall–runoff ratio that has been resilient to watershed changes. Reservoir sedimentation rates generally were higher before 1963, but have been much lower and very stable since that time. Our findings suggest that (1) rangeland water yields may be stable over long periods despite dramatic landscape changes while (2) these same landscape changes influence sediment yields that impact downstream reservoir storage. Relying on rangelands to meet water needs demands an understanding of how these dynamic landscapes function and a quantification of the physical processes at work.

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

Effect of Shrub Planting on Runoff and Sediment under Simulated Rainfall

2012 ◽  
Vol 212-213 ◽  
pp. 141-144
Author(s):  
Pei Qing Xiao ◽  
Wen Yi Yao ◽  
Chang Gao Wang
Keyword(s):  
Shear Stress ◽  
Sediment Yield ◽  
Simulated Rainfall ◽  
Slope Gradient ◽  
Flow Shear ◽  
Sediment Yields ◽  
Hydraulic Mechanism ◽  
Flow Shear Stress ◽  
Sediment Reduction ◽  
Runoff And Sediment Yield

Effect of shrub on runoff and sediment yield and its hydraulic mechanism of shrub were studied under rainfall intensities of 45, 87 and 127mm/h with 20°slope gradient using simulated rainfall experiment. the results showed that average runoff rates ranged from 39.7 to 126.0 L/min for bare plots and 0.77 to 4.83 L/min for shrub plots, and the runoff rates from shrub plots were much less than from bare plots. Average sediment yields varied from 3636.7 to 9436.3 g/min for bare plots and from 28.0 to 421.6 g/min for shrub plots. The critical flow shear stress of 1.65 N/m2 on shrub slope and 0.861 N/m2 on bare slope were got under experiment condition. The sediment yield increased with the increase of flow shear stress. The experiment results are meaningful for quantifying runoff and sediment reduction and deepening soil erosion mechanical process also.

Methods of Estimating Runoff and Soil Loss in Plots under Different Plant Densities of Amaranthus

2009 ◽  
Vol 62-64 ◽  
pp. 247-257
Author(s):  
C.S. Okoli
Keyword(s):  
Sediment Yield ◽  
Block Design ◽  
Sediment Yields ◽  
Randomized Block Design ◽  
Run Off ◽  
Engineering Department ◽  
Plant Densities ◽  
Rainfall Runoff Model ◽  
Level Of Significance ◽  
Runoff And Sediment Yield

This paper reports of study that was conducted to evaluate runoff rates and sediment yield as affected by different plant densities of amaranthus at the experimental farm of Agricultural Engineering Department, Federal University of Technology, Akure, Ondo State, Nigeria. The experimentally based study is aimed at determining the runoff and sediment yield relationship as affected by different plant densities of amaranthus at the experimental farm. Treatment were based on four plant densities A (97 plant/m2) B (42 plant/m2) C (125 plant/m2) D (69 plant/m2), runoff depths and sediment yields were measured during the months of August to November 2003. A complete randomized block design was used to evaluate treatment methods on the basis of sediment yield and run off depth. A rainfall-Runoff model was established to enable future occurrence to be predicted. The water balance equation was used to compute the evapotransipiration (ET) for each plot. There were significant differences in sediment yields and run off depths among the treatments at 5% level of significance treatment. A (97 plant/m2) and C (125 plant/m2) were found to have the least amount of runoff and sediment yield, while treatment B (42 plant/m2) and D(69 plants/m2) had the highest amount of runoff and sediment yield. The result confirms the proposition that increased plant densities had a significant effect in reducing runoff and sediment for agricultural lands.

Evaluation of EPIC's snowmelt and water erosion submodels using data from the Peace River region of Alberta

1997 ◽  
Vol 77 (1) ◽  
pp. 41-50 ◽  
Author(s):  
H. Puurveen ◽  
R. C. Izaurralde ◽  
D. S. Chanasyk ◽  
J. R. Williams ◽  
R. F. Grant
Keyword(s):  
Sediment Yield ◽  
Water Erosion ◽  
Weather Data ◽  
Canadian Prairie ◽  
Sediment Yields ◽  
Runoff Volume ◽  
River Region ◽  
Daily Weather Data ◽  
Using Data ◽  
Runoff And Sediment Yield

Water erosion due to snowmelt is a major form of erosion in boreal regions of the Canadian Prairie. Evaluation of erosion models is an essential step before recommending their use in local or regional assessments of erosion rates and control methods. Using inputs from a runoff study conducted at La Glace, Alberta (55°25'N, 119°10'W) from 1984 to 1986, we evaluated the Erosion-Productivity Impact Calculator (EPIC) for its ability to simulate runoff and sediment yield from snowmelt events. The model was initialized with soil profile data acquired at the study site and complemented with data from standard soil databases (Albright series; loam, Dark Gray Chernozem). Daily weather data were acquired from the nearest climatological station (annual precipitation = 475 mm). Management data were as reported and included combinations of conventional and reduced tillage, annual and perennial, and fallow cropping. Mean runoff volume measured in 1985 was 57 mm while in 1986 it was 76 mm. EPIC over-predicted runoff volume by 25% in 1985 but under-predicted it by 7% in 1986. The period in which snowmelt occurred (mid-March – beginning of April) was predicted correctly. Under the conditions of this study, with many cropping inputs obtained from different sources, the model was unable to reproduce the reported management effects on runoff and sediment yield. EPIC simulated springmelt soil temperature trends at 9-cm depth, although the predicted temperatures in 1985 were generally underestimated. Our results suggest that the EPIC model calculates adequate values of runoff volumes and sediment yields during snowmelt. Key words: Runoff, sediment yield, soil erosion, crop rotations

scholarly journals Storm-wise sediment yield prediction using hillslope erosion model in semi-arid abundant lands

2013 ◽  
Vol 8 (No. 1) ◽  
pp. 42-48 ◽  
Author(s):  
S. Fazli ◽  
H. Noor
Keyword(s):  
Soil Erosion ◽  
Sediment Yield ◽  
Land Surface ◽  
Soil Conservation ◽  
Soil Erodibility ◽  
Storm Events ◽  
Erosion Model ◽  
Sediment Yields ◽  
Slope Steepness ◽  
Erosion Models

Evaluation of soil erosion by existing models is needed as an important tool for managerial purposes in designation of proper water and soil conservation techniques. The present study aimed to assess the applicability of hillslope erosion model (HEM) as one of the newest erosion models for prediction of storm-wise sediment yield in Khosbijan rangeland with 20% slope steepness by using soil erosion standard plots. In order to run the model, runoff depth, land surface cover, soil texture, slope steepness and length were determined for 16 storm events. The results showed that the uncalibrated HEM did not simulate the observed sediment yields properly. Calibration of soil erodibility parameter and developing regression between observed and estimated data indicated that the model was capable of predicting sediment yield in plots by applying soil erodibility parameter of 0.15 with determination coefficient of 0.64 and estimate error of 40%. 

Landscape Patches Influencing Runoff and Sediment Yield and Flow Hydrodynamics in The Loess Plateau, China

2021 ◽  
Author(s):  
Ruoxiu Sun ◽  
Jianjun Zhang ◽  
Li Ma
Keyword(s):  
Loess Plateau ◽  
Sediment Yield ◽  
The Loess Plateau ◽  
Stream Power ◽  
Patch Type ◽  
Vegetation Patch ◽  
Sediment Yields ◽  
Bare Land ◽  
Vegetation Patches ◽  
Runoff And Sediment Yield

<p>The Loess Plateau is located in arid and semi-arid region, and the fragmentation of vegetation patches is large. However, the combination of vegetation patches to the runoff and sediment yield on the slope is not clear yet. To evaluate the influence of vegetation patch type and number on runoff, sediment and hydrodynamic parameters, this study established field runoff plots with different landscape patch types, including bare land, S-road patches, strip patches, grid patches and random patches, as well as different quantities patches of 5, 10, 15 and 20. The results showed that the runoff yields of the four vegetation patch types decreased by 16.1%–48.7% (p<0.05) compared with that of bare land, whereas sediment yields decreased by 42.1%–86.5% (p<0.05). Also, the resistance coefficients of the poorly connected patch patterns, including strip patches, grid patches and random patches, ranged between 0.2–1.17 times higher than that of the well-connected S-road patch pattern, and the stream power decreased by 33.3%–50.7% (p<0.05). Under a uniform distribution of vegetation patches, the runoff rate and sediment yield decreased significantly with an increased number of patches. Although the increase in the number of vegetation patches also resulted in a decrease inflow shear stress and stream power to different degrees, the differences between the combinations with similar patch numbers were not significant. Besides, the sensitivity of soil to erosion decreased with an increasing number of the patch in the vegetation landscape, whereas the sensitivities of patch combinations with poor connectivity were lower than those with good connectivity. From this perspective, the optimization of vegetation in the Loess Plateau region requires sufficient consideration to reducing the connectivity of vegetation patches and increasing the density of patches.</p>

scholarly journals Assessment of Climate Change and Associated Vegetation Cover Change on Watershed-Scale Runoff and Sediment Yield

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1373 ◽  
Author(s):  
Shanghong Zhang ◽  
Zehao Li ◽  
Xiaonan Lin ◽  
Cheng Zhang
Keyword(s):  
Climate Change ◽  
Sediment Yield ◽  
Vegetation Cover ◽  
General Circulation ◽  
Climate Change Scenarios ◽  
Watershed Scale ◽  
Emission Scenarios ◽  
Base Period ◽  
Average Annual Runoff ◽  
Runoff And Sediment Yield

Climate change has an important impact on water balance and material circulation in watersheds. Quantifying the influence of climate and climate-driven vegetation cover changes on watershed-scale runoff and sediment yield will help to deepen our understanding of the environmental effects of climate change. Taking the Zhenjiangguan Watershed in Sichuan Province, China as a case study, three downscaled general circulation models with two emission scenarios were used to generate possible climatic conditions for three future periods of P1 (2020–2039), P2 (2050–2069) and P3 (2080–2099). Differences in scenarios were compared with the base period 1980–1999. Then, a Normalized Difference Vegetation Index climate factor regression model was established to analyze changes to vegetation cover under the climate change scenarios. Finally, a Soil and Water Assessment Tool model was built to simulate the response of runoff and sediment yield in the three future periods under two different scenarios: only changes in climate and synergistic changes in climate and vegetation cover. The temperature and precipitation projections showed a significant increasing trend compared to the baseline condition for both emission scenarios. Climate change is expected to increase the average annual runoff by 15%–38% compared with the base period, and the average annual sediment yield will increase by 4%–32%. The response of runoff and sediment yield varies in different periods, scenarios, and sub-watersheds. Climate-driven vegetation cover changes have an impact on runoff and sediment yield in the watershed, resulting in a difference of 5.8%–12.9% to the total changes. To some extent, the changes in vegetation cover will inhibit the hydrological impact of climate changes. The study helps to clarify the effects of climate and vegetation cover factors on hydrological variations in watersheds and provides further support for understanding future hydrological scenarios and implementing effective protection and use of water and soil resources.

Simulation of sub-basin sediment yields and river runoffs into Davao Gulf, Philippines

2020 ◽  
Author(s):  
Adonis Gallentes ◽  
Peter Jeffrey Maloles ◽  
Cesar Villanoy
Keyword(s):  
Land Use ◽  
Sediment Yield ◽  
Land Surface ◽  
River Discharge ◽  
Marine Protected Area ◽  
Marine Ecosystem ◽  
The Philippines ◽  
Marine Biodiversity ◽  
Surface Erosion ◽  
Sediment Yields

<p>The Philippines is a country within the Coral Triangle which is known to be the center of the most biologically diverse marine ecosystem in the world. Despite being a crucial area for marine biodiversity, discharge measurements of many rivers in the country are either sparse or non-existent. Such data are important in assessing aspects such as sedimentation which is highly related to the health of the reef community.</p><p>Here, we applied SWAT hydrological model in order to simulate the sediment yield of sub-basins and river discharge surrounding Davao Gulf, one of the country’s richest zones in terms of fish production. Monthly-averaged results of the model from 2001 to 2018 indicate that the relative maxima of sediment yield coincide with precipitation maxima, and that consecutive rainfall events which start around midyear results to higher erodibility and thus, higher peaks in sediment yield during the second half of each year until the early part of the following year. Dependence of sediment yield on slope class/angle and land use was also observed, identifying the northwestern catchments as critical sources of land surface erosion. Good agreement was obtained between simulations of river discharge and the sparse observed streamflow values during model validation (Davao River: NSE=0.61, R<sup>2</sup>=0.61, PBIAS = 2.87, r= 0.78; Hijo River: NSE=0.62, R<sup>2</sup>=0.90, PBIAS = -2.1630, r= 0.95).</p><p>Overall, this modeling study helped fill in the temporal gaps of observed streamflow data from river gauges, and provided estimates of the historical streamflow pattern of those rivers with no river gauges. Outputs of this study can also be used as science-based reference in crafting laws and ordinances for proper land use and Marine Protected Area (MPA) management plans, with emphasized consideration of the likely effects of climate change such as the latitudinal shift of typhoon tracks, increasing temperature, and more pronounced precipitation events which have already been observed in the area during the past two decades. </p>

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