scholarly journals Runoff and sediment yield modeling in a medium-size mediterranean watershed

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Ossama M.M. Abdelwahab ◽  
Tiziana Bisantino ◽  
Fabio Milillo ◽  
Francesco Gentile
Keyword(s):  
Sediment Yield ◽  
Soil Conservation ◽  
Management Practices ◽  
Southern Italy ◽  
Medium Size ◽  
Validation Process ◽  
Yield Data ◽  
Event Scale ◽  
Prediction Capability ◽  
Runoff And Sediment Yield

The AnnAGNPS model was used to estimate runoff, peak discharge and sediment yield at the event scale in the Carapelle watershed, a Mediterranean medium-size watershed (506 km2) located in Apulia, Southern Italy. The model was calibrated and validated using five years of runoff and sediment yield data measured at a monitoring station located at Ordona – Ponte dei Sauri Bridge. A total of 36 events was used to estimate the output of the model during the period 2007-2011, in comparison to the corresponding observations at the watershed outlet. The model performed well in predicting runoff, as was testified by the high values of the coefficients of efficiency and determination during the validation process. The peak flows predictions were satisfactory especially for the high flow events; the prediction capability of sediment yield was good, even if a slight over-estimation was observed. Finally, the model was used to evaluate the effectiveness of different Management practices (MPs) on the watershed (converting wheat to forest, using vegetated streams, crop rotation corn/soybean, no tillage). While the maximum reduction in sediment yield was achieved converting wheat to forest, the best compromises between soil conservation and agriculture resulted to be crop rotations.

Effects of vegetation as an ecosystem service on the changes in runoff and sediment yield in a Mediterranean semi-arid basin

2021 ◽  
Author(s):  
María Rosario Vidal-Abarca Gutiérrez ◽  
Alberto Martínez-Salvador ◽  
Carmelo Conesa-García ◽  
María Luisa Suárez-Alonso ◽  
Francisco Alonso-Sarria ◽  
...  
Keyword(s):  
Sediment Yield ◽  
Ecosystem Service ◽  
Vegetation Cover ◽  
Pressure Sensors ◽  
Erosion Control ◽  
Water Levels ◽  
Event Scale ◽  
Dynamic Component ◽  
Sediment Loads ◽  
Runoff And Sediment Yield

<p>Semiarid basins contribute significantly to sediment loads, as they are often characterized by torrential flows, source areas with high sediment-producing rates, great availability of erodible material subjected to intense weathering processes, and poor vegetation cover. Vegetation, despite its scarce presence, is a dynamic component of this environment, which provides a range of important ecosystem services such as biodiversity, flood retention, nutrient sink, erosion control and groundwater recharge. This study examines the vegetation responses to the magnitude of peak flows and its contribution to the changes in runoff and sediment yield during the period 1997-2020 in a catchment Mediterranean semiarid basin: The Rambla de la Azohía (southeastern Spain).Vegetation type, density, preferred location and degree of permanence in each sub-basin were analyzed in order to determine their degree of influence on surface runoff and erosion control. Changes in riparian vegetation cover was quantified at large scale for the analysis period (1997-2020), using remotely sensed spatial information, such as satellite images and aerial photographs separated by two years on average (at scales from 1:15000 to 1:30000, and resolution between 0.22 and 0.50 m/pixel). A geo-spatial erosion prediction model was applied to estimate the runoff and sediment load generated at the event scale, taking into account the variability of the vegetation cover in each sub-basin. The simulated outputs of this model were previously calibrated with water levels measured by pressure sensors and suspended sediment records.The results showed both a poor response of vegetation (low incidence in the runoff coefficient) in steep metamorphic watersheds, capable of supplying large sediment loads, and functioned as an efficient ecosystem service (stabilization of slopes and decrease in peak flow) in less steep sub-basins with slopes in the shadow, composed of limestone formations and alluvial fans. This suggests important spatial differences in the vegetation impact, according to other environmental conditions intrinsic to each sub-basin, but also a low overall influence on the temporal variability of sediment fluxes at the event scale. This research was funded by FEDER/Spanish Ministry of Science, Innovation and Universities—State Research Agency (AEI)/Projects CGL2017-84625-C2-1-R and CGL2017-84625-C2-2-R; State Program for Research, Development and Innovation Focused on the Challenges of Society.</p>

scholarly journals Event-based runoff and sediment yield dynamics and controls in the sub-humid headwaters of the Blue Nile, Ethiopia

2021 ◽  
Author(s):  
Habtamu Assaye Deffersha ◽  
Jan Nyssen ◽  
Jean Poesen ◽  
Hanibal Lemma ◽  
Derege Meshesha ◽  
...  
Keyword(s):  
Land Use ◽  
Land Management ◽  
Sediment Yield ◽  
Management Practices ◽  
Sediment Concentration ◽  
Rock Fragment ◽  
Grazing Land ◽  
The Mean ◽  
The Impact ◽  
Runoff And Sediment Yield

Land degradation due to soil erosion presents a challenge for sustainable development. We investigated the impact of land use type and land management practices on runoff and sediment yield dynamics in the northwestern highlands of Ethiopia. The study area included 14 zero-order catchments with a surface area ranging from 324 m2 to 1715 m2. V-notch weirs produced from plastic jars were introduced as measuring alternatives that met local constraints. Runoff depth at the weir was registered at 5-min intervals during two rainy seasons in 2018 and 2019. Rainfall was measured using tipping-bucket rain gauges. Runoff samples were collected in 1-L bottles and suspended sediment concentration (SSC) was determined. The mean event runoff coefficient ranged from 3% for forests to 56% for badlands. Similarly, the mean annual sediment yield (SY) was lowest for forests (0.8 Mg ha-1 yr-1) and highest for badlands (43.4 Mg ha-1 yr-1), with significant differences among land use types (14.8 Mg ha-1 yr-1 in cropland, 5.7 Mg ha-1 yr-1 in grazing land, and 2.9 Mg ha-1 yr-1 in plantations). Soil organic matter (SOM) reduced runoff and SY, necessitating the consideration of agronomic and land management practices that enhance SOM. Annual SY decreased exponentially with the rock fragment cover (RFC). In fields where RFC was less than 20%, collecting rock fragments for installing stone bunds resulted in a net increase in SY. Rehabilitating badlands and enhancing SOM content in croplands can substantially reduce catchment SY and, hence considerably contribute to the sustainability of this type of environment.

scholarly journals Modelling of runoff and sediment yield using ANN, LS-SVR, REPTree and M5 models

2017 ◽  
Vol 48 (6) ◽  
pp. 1489-1507 ◽  
Author(s):  
Birendra Bharti ◽  
Ashish Pandey ◽  
S. K. Tripathi ◽  
Dheeraj Kumar
Keyword(s):  
Sediment Yield ◽  
Sunshine Duration ◽  
Least Square ◽  
Coefficient Of Determination ◽  
Support Vector ◽  
Hydrological Process ◽  
M5 Model Tree ◽  
Yield Data ◽  
Input Variables ◽  
Runoff And Sediment Yield

Abstract In this study, the performance evaluation of five machine learning models, namely, ANNLM, ANNSCG, least square-support vector regression (LS-SVR), reduced error pruning tree (REPTree) and M5, was carried out for predicting runoff and sediment in the Pokhariya watershed, India using hydro-meteorological variables as input. The input variables were selected using the trial-and-error procedure which represents the hydrological process in the watershed. The seven input variables to all the models comprised a combination of rainfall, average temperature, relative humidity, pan evaporation, sunshine duration, solar radiation and wind speed. The monthly runoff and sediment yield data were used to calibrate and validate all models for the years 2000 to 2008. Evaluation of models' performances were carried out using four statistical indices, i.e., Nash–Sutcliffe coefficient (NSE), coefficient of determination (R2), percent bias (PBIAS) and RMSE-observations standard deviation ratio (RSR). Comparative analysis showed that the ANNLM model marginally outperformed the LS-SVR model and all the other models investigated during calibration and validation for runoff modelling whereas the LS-SVR model surpassed the artificial neural networks (ANN) model and other models for sediment yield modelling. Moreover, M5 model tree is better in simulating sediment yield and runoff than its near counterpart, the REPTree model, and marginally inferior when compared to LS-SVR and ANN models.

scholarly journals Effectiveness of alternative management scenarios on the sediment load in a Mediterranean agricultural watershed

2014 ◽  
Vol 45 (3) ◽  
pp. 125 ◽  
Author(s):  
Ossama M. M. Abdelwahab ◽  
Ronald L. Bingner ◽  
Fabio Milillo ◽  
Francesco Gentile
Keyword(s):  
Soil Erosion ◽  
Management Practices ◽  
Sediment Load ◽  
Source Model ◽  
Agricultural Watershed ◽  
Medium Size ◽  
Management Scenarios ◽  
Forage Crop ◽  
Alternative Management ◽  
Prediction Capability

The Annualised Agricultural Non-point Source model was used to evaluate the effectiveness of different management practices to control the soil erosion and sediment load in the Carapelle watershed, a Mediterranean medium-size watershed (506 km<sup>2</sup>) located in Apulia, Southern Italy. The model was previously calibrated and validated using five years of runoff and sediment load data measured at a monitoring station located at Ordona - Ponte dei Sauri Bridge. A total of 36 events were used to estimate the performance of the model during the period 2007-2011. The model performed well in predicting runoff, as the high values of the coefficients of efficiency and determination during the validation process showed. The peak flows predictions were satisfactory especially for the high flow events; the prediction capability of sediment load was good, even if a slight over-estimation was observed. Simulations of alternative management practices show that converting the most eroding cropland cells (13.5% of the catchment area) to no tillage would reduce soil erosion by 30%, while converting them to grass or forest would reduce soil erosion by 36.5% in both cases. A crop rotation of wheat and a forage crop can also provide an effective way for soil erosion control as it reduces erosion by 69%. Those results can provide a good comparative analysis for conservation planners to choose the best scenarios to be adopted in the watershed to achieve goals in terms of soil conservation and water quality.

Impacts of climate and land use changes on the erosion processes in a Mediterranean agricultural catchment (Northern Morocco)

2021 ◽  
Author(s):  
Hamza Briak ◽  
Rachid Moussadek ◽  
Khadija Aboumaria ◽  
Fassil Kebede ◽  
Rachid Mrabet
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Best Management Practices ◽  
Sediment Yield ◽  
Soil Conservation ◽  
Management Practices ◽  
Agricultural Land ◽  
Swat Model ◽  
Baseline Scenario ◽  
Erosion Processes

&lt;p&gt;Recent studies on vulnerability to climate and land use change show a trend towards increased aridity accelerating soil erosion which is the primary factor to be considered by decision makers in the environmental field. Furthermore, to reduce the soil erosion intensity, it is required to clarify the sources zones of sediment yield where soil conservation works have to focus on. The model selected for this work is the Soil and Water Assessment Tool (SWAT) which is one of many models widely used to assess soil erosion risk and simulate conservation measures efficiency. In fact, the objective of this work is to evaluate the effects of different agricultural Best Management Practices (BMPs) on sediments using SWAT model in the Kalaya river basin located in the North of Morocco in order to recommend the most appropriate one. The model was calibrated and validated using observed data of flow and sediment concentration; the performance of the model was evaluated using statistical methods and the total soil erosion rate was estimated by this model in the study area. However, we concentrated on the representation of three interesting and most usable practices by the SWAT model: contouring, strip-cropping and terracing. The general parameters of the model have been modified to reflect the implementation of four different BMPs. The modification of these parameters was based on previous research and modeling efforts conducted in watersheds. Resulting sediment yield were compared with the result of simulation of the baseline scenario (existing conditions). In fact, effective measures to reduce sediment losses at the watershed level are organized according to their effectiveness, and these are terracing (28% reduction and the value is 15t/ha/y) followed by strip-cropping (9% reduction and the value is 5t/ha/y). On the other hand, measurements performed by the contouring are inappropriate for the study area because they have contributed to increasing the soil erosion (more than 31% of losses and the value is 17t/ha/y more than existing conditions). The mean annual values of sediment yields obtained for scenarios with and without BMPs were compared to assess the effectiveness of BMPs. Among all other practices, terracing was the most effective BMPs for reducing sediments which is perfectly recommended in the Mediterranean regions in general to avoid the risk of damage during intense rainfall. These results indicates that the use of terracing on agricultural land can potentially make improvements marked the control and limitation of soil erosion, and it also affords useful information for involved stakeholders in water and soil conservation activities for targeted management.&lt;/p&gt;

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.

Sign in / Sign up

Export Citation Format

Share Document