scholarly journals Measuring land losses caused by water erosion using the SWAT model in the Ourika watershed in the High Atlas of Morocco

2021 ◽  
Vol 234 ◽  
pp. 00083
Author(s):  
Meysara Elmalki ◽  
Fouad Mounir ◽  
Abdellah Ichen ◽  
Taoufiq Qaini ◽  
Thami Khai ◽  
...  

In Morocco, the phenomena of water erosion cause significant economic losses mainly linked to the silting up of dams, the degradation of equipment and socio-economic infrastructures, the loss of soil productivity and the insecurity of the population. The SWAT (Soil and Water Assessment Tool) model was used to estimate the quantities of sediments generated by the various erosive processes at the level of the Ourika watershed. The SWAT modeling, which is done with daily time steps, used as basic data; a Digital Elevation Model GDEM-ASTER (Global Digital Elevation-Advanced Space borne Thermal Emission and Reflection Radiometer) with 30 m of resolution, a land cover map developed from the Landsat 8 OLI (Operational Land Imager) satellite image of 2017 with 30 m of resolution and a soil map published by FAO (Harmonized World Soil Database). Also, daily meteorological data from the Tensift Water Basin Agency over a period from 1992 to 2001 were used. The results obtained showed that soil losses due to water erosion in the Ourika watershed reached an average of 9.18 t.ha-1.year-1. The model was calibrated and validated using the SWAT-CUP (SWAT Calibration and Uncertainty Procedures) software SUFI-2 (Sequential Uncertainty Fitting) and after several simulations and iterations a determination coefficient R2 of 0.76 was obtained.

2019 ◽  
Vol 69 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Mohammad Nazari-Sharabian ◽  
Masoud Taheriyoun ◽  
Moses Karakouzian

Abstract This study investigates the impact of different digital elevation model (DEM) resolutions on the topological attributes and simulated runoff, as well as the sensitivity of runoff parameters in the Mahabad Dam watershed in Iran. The watershed and streamlines were delineated in ArcGIS, and the hydrologic analyses were performed using the Soil and Water Assessment Tool (SWAT). The sensitivity analysis on runoff parameters was performed, using the Sequential Uncertainties FItting Ver. 2 algorithm, in the SWAT Calibration and Uncertainty Procedures (SWAT-CUP) program. The results indicated that the sensitivity of runoff parameters, watershed surface area, and elevations changed under different DEM resolutions. As the distribution of slopes changed using different DEMs, surface parameters were most affected. Furthermore, higher amounts of runoff were generated when DEMs with finer resolutions were implemented. In comparison with the observed value of 8 m3/s at the watershed outlet, the 12.5 m DEM showed more realistic results (6.77 m3/s). Comparatively, the 12.5 m DEM generated 0.74% and 2.73% more runoff compared with the 30 and 90 m DEMs, respectively. The findings of this study indicate that in order to reduce computation time, researchers may use DEMs with coarser resolutions at the expense of minor decreases in accuracy.


2018 ◽  
Vol 162 ◽  
pp. 03008 ◽  
Author(s):  
Imzahim Abdulkareem Alwan ◽  
Ibtisam Karim ◽  
Mahmood Mohamed

Sediment production is the amount of sediment in the unit area that is transported through the basin by water transfer over a specified period of time. The main aim of present study is to predict sediment yield of Wadi, Al-Naft watershed with 8820 Km2area, that is located in the North-East of Diyala Governorate in Iraq, using Soil-Water Assessment Tool, (SWAT) and to predict the impact of land management and the input data including the land use, soil type, and soil texture maps which are obtained from Landsat-8 satellite image. Digital Elevation Model,(DEM) with resolution (14 14) meter is used to delineate the watershed with the aid of model. Three Land-sat images were used to cover the study area which were mosaic processed and the study area masked- up from the mosaic, image. The area of study has been registries by Arc-GIS 10.2 and digitized the soil hydrologic group through assistant of Soil Plant Assistant Water Model, (SPAW) which was progressed by USDA, Agricultural, Research Service, using the data of soil textural and organic matter from Food and Agriculture Organization (FAO), the available water content, saturated hydraulic conductivity, and bulk density. The results of average, sediment depth and the maximum upland sediment for simulation period (2010-2020) were predicted to be (1.7 mm), and (12.57 Mg/ha), respectively.


2020 ◽  
Vol 12 (4) ◽  
pp. 643 ◽  
Author(s):  
Michaela Rättich ◽  
Sandro Martinis ◽  
Marc Wieland

Flood duration is a crucial parameter for disaster impact assessment as it can directly influence the degree of economic losses and damage to structures. It also provides an indication of the spatio-temporal persistence and the evolution of inundation events. Thus, it helps gain a better understanding of hydrological conditions and surface water availability and provides valuable insights for land-use planning. The objective of this work is to develop an automatic procedure to estimate flood duration and the uncertainty associated with the use of multi-temporal flood extent masks upon which the procedure is based. To ensure sufficiently high observation frequencies, data from multiple satellites, namely Sentinel-1, Sentinel-2, Landsat-8 and TerraSAR-X, are analyzed. Satellite image processing and analysis is carried out in near real-time with an integrated system of dedicated processing chains for the delineation of flood extents from the range of aforementioned sensors. The skill of the proposed method to support satellite-based emergency mapping activities is demonstrated on two cases, namely the 2019 flood in Sofala, Mozambique and the 2017 flood in Bihar, India.


Author(s):  
Abdata Galata

Modelling the hydrological characteristics of watershed is a method of understanding behavior and simulating the water balance components of watershed for planning and development of integrated water resources management. The soil and water assessment tool (SWAT) physically based hydrological modelling was used for modelling hydrologic characteristics of the Hangar watershed. The data used for this study were digital elevation model (DEM), land use land cover data, soil map, climatological and hydrological data. The model calibrated and validated using measured streamflow data of 13 years (1990-2002) and 9 years (2003-2011) respectively including warm-up period. The SWAT model performs well for both calibration (R2 = 0.87, NSE = 0.82 and PBIAS = +1.4) and validation (R2 = 0.89, NSE = 0.88 and PBIAS = +1.2). The sensitivity analysis, which was carried out using 18 SWAT parameters, identified the 13 most sensitive parameters controlling the output variable and with which goodness-of-fit was reached. The analysis results indicated that the watershed receives around, 9.6%, 59.9%, and 30.5% precipitation during dry, wet and short rainy seasons respectively. The received precipitation was lost by 9.6 %, 40.5%, and 41.3% in the form of evapotranspiration for each seasons correspondingly. The surface runoff contribution to the Watershed were 3.8%, and 79.2% during dry and wet seasons respectively, whereas, it contributes by 17.0% during short rainy seasons.


2020 ◽  
Vol 4 (2) ◽  
pp. 90-95
Author(s):  
Ibrahim Sufiyan ◽  
Magaji J.I ◽  
A.T. Ogah

Risks and hazards are two important issues currently threatening humanity and the environment. Flood has claimed many lives and destroyed properties in Malaysia and Africa and Nigeria. It is global catastrophe. The application of geospatial science is, therefore, very important advantages that it offers solutions to flood. This stud uses of Advanced Space-borne Thermal Emission and Reflection Radiometer Digital Elevation Model (ASTER-DEM), and the Soil Water Assessment Tool (SWAT) in visualizing floods disaster risk. The whole catchment area of Terengganu has been delineated. The 25 sub-basins have been identified and the flood risk zones have been modeled. The complete watersheds are characterized by different sub-basins and Hydrologic Respond Units (HRUs) which can be viewed in 3D environment.


2018 ◽  
Vol 10 (10) ◽  
pp. 1629 ◽  
Author(s):  
Ryu Sugimoto ◽  
Toru Kouyama ◽  
Atsunori Kanemura ◽  
Soushi Kato ◽  
Nevrez Imamoglu ◽  
...  

Accurate attitude information from a satellite image sensor is essential for accurate map projection and reducing computational cost for post-processing of image registration, which enhance image usability, such as change detection. We propose a robust attitude-determination method for pushbroom sensors onboard spacecraft by matching land features in well registered base-map images and in observed images, which extends the current method that derives satellite attitude using an image taken with 2-D image sensors. Unlike 2-D image sensors, a pushbroom sensor observes the ground by changing its position and attitude according to the trajectory of a satellite. To address pushbroom-sensor observation, the proposed method can trace the temporal variation in the sensor attitude by combining the robust matching technique for a 2-D image sensor and a non-linear least squares approach, which can express gradual time evolution of the sensor attitude. Experimental results using images taken from a visible and near infrared pushbroom sensor of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) onboard Terra as test image and Landsat-8/OLI images as a base map show that the proposed method can determine satellite attitude with an accuracy of 0.003° (corresponding to the 2-pixel scale of ASTER) in roll and pitch angles even for a scene in which there are many cloud patches, whereas the determination accuracy remains 0.05° in the yaw angle that does not affect accuracy of image registration compared with the other two axes. In addition to the achieved attitude accuracy that was better than that using star trackers (0.01°) regarding roll and pitch angles, the proposed method does not require any attitude information from onboard sensors. Therefore, the proposed method may contribute to validating and calibrating attitude sensors in space, at the same time better accuracy will contribute to reducing computational cost in post-processing for image registration.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Waranyu Buakhao ◽  
Anongrit Kangrang

A digital elevation model (DEM) is an important spatial input for automatic extraction of topographic parameters for the soil and water assessment tool (SWAT). The objective of this study was to investigate the impact of DEM resolution (from 5 to 90 m) on the delineation process of a SWAT model with two types of watershed characteristics (flat area and mountain area) and three sizes of watershed area (about 20,000, 200,000, and 1,500,000 hectares). The results showed that the total lengths of the streamline, main channel slope, watershed area, and area slope were significantly different when using the DEM datasets to delineate. Delineation using the SRTM DEM (90 m), ASTER DEM (30 m), and LDD DEM (5 m) for all watershed characteristics showed that the watershed sizes and shapes obtained were only slightly different, whereas the area slopes obtained were significantly different. The total lengths of the generated streams increased when the resolution of the DEM used was higher. The stream slopes obtained using the small area sizes were insignificant, whereas the slopes obtained using the large area sizes were significantly different. This suggests that water resource model users should use the ASTER DEM as opposed to a finer resolution DEM for model input to save time for the model calibration and validation.


Author(s):  
Farinaz Gholami ◽  
Alireza Nemati ◽  
Yue Li ◽  
Yang Hong ◽  
Junlong Zhang

The Digital Elevation Model (DEM) of a watershed is one of the most important inputs in most hydrological analyses and plays a key role in the accurate prediction of various hydrological processes. Comprehensive knowledge of the impact of different DEM sources on the performance of a model is essential before utilizing the model. In this study, we evaluated the influence of TOPO1:25000, ASTER, and SRTM DEMs, as input, on the performance of the Soil and Water Assessment Tool (SWAT) model for the prediction of surface runoff. We also investigated the effect of the resolution of the studied DEM sources on the accuracy of the SWAT model in the estimation of runoff. The second objective of this study was to identify the most influential and the least impactful input parameters on the performance of the SWAT model. We studied the Zarrineh River watershed in Iran as a case study to compare the effect of the aforementioned DEM types and DEM resolution on the output of the SWAT model. The outcomes of the study demonstrated that influential parameters on predicted runoff as well as a few watershed parameters, such as reach lengths, reach slopes, number of sub-basins, and the number of hydrologic response units (HRU), differs noticeably when the DEM source and resolution changes. It was also observed that simulated results over-predict the runoff during low precipitation periods and under-predict the runoff during high precipitation months, and the accuracy of the simulated results decreases by reducing the DEM resolution. The results showed that the SWAT model had the best performance when the TOPO1:25000 DEM was used as the input source. Low-resolution DEMs are available to a wider range of researchers. The outcomes of the current study can be employed to estimate the impact of low-resolution input data on the simulated result as well as substantially reduce the computation time by decreasing the input DEMresolution with only a minor reduction of accuracy.


2019 ◽  
Vol 4 (4) ◽  
pp. 444-457 ◽  
Author(s):  
Adisu Befekadu Kebede

This study aimed to model the flow of streams and identify the sub-basins responsible for the high flow in the Didessa watershed, southwest Ethiopia, considering the regional soils types. Soil and Water Assessment Tool (SWAT) model was used to simulate stream flow and quantify surface runoff. The input data used were Digital Elevation Model (DEM), land use/land cover map, soil map and metrological data. The data were obtained from Ministry of Water, Irrigation and Electricity and National Meteorology Agency of Ethiopia. Simulation of SWAT was used to identify the most vulnerable sub-basins to the hydrological process. The model was calibrated and validated using the stream flow data. The simulated stream flow was calibrated by the SWAT-CUP2012 calibration sub-model of SWAT-CUP SUFI2. Sensitivity analysis showed that curve numbers (CN2), ALPHA-BNK and CH-K2 are the most sensitive top three parameters. The R2 and Nash-Sutcliffe Efficiency (NSE) values were used to examine the model performance. The results indicate 0.84 and 0.80 for R2 and 0.65 and 0.54 for NSE during calibration and validation, respectively. The average annual surface runoff in the delineated catchment was 774.13 mm. Changes in precipitation explained 89% of the variation in surface runoff, as more than 89% of precipitation from the catchment converted to surface runoff. The most three annual surface runoffs contributing were the 11, 23 and 5 sub-basins. INFLUÊNCIA DO TIPO DE SOLO NO FLUXO DE CÓRREGOS PARA A BACIA SUPERIOR DO RIO DIDESSA, SUDOESTE DA ETIÓPIA UTILIZANDO O MODELO SWATResumoEste estudo teve como objetivo modelar o fluxo de córregos e identificar as sub-bacias responsáveis pelo alto fluxo na bacia hidrográfica do Rio Didessa, sudoeste da Etiópia, considerando os tipos de solos regionais. O modelo SWAT (Solo and Water Assessment Tool) foi utilizado para simular o fluxo da corrente e quantificar o escoamento superficial. Os dados de entrada utilizados foram o Modelo Digital de Elevação (DEM), mapa de uso / cobertura do solo, mapa do solo e dados metrológicos. Os dados foram obtidos no Ministério da Água, Irrigação e Eletricidade e Agência Nacional de Meteorologia da Etiópia. A simulação do SWAT foi utilizada para identificar as sub-bacias mais vulneráveis ao processo hidrológico. O modelo foi calibrado e validado usando os dados de fluxo dos córregos. O fluxo de corrente simulado foi calibrado pelo submodelo de calibração SWAT-CUP2012, do SWAT-CUP SUFI2. A análise de sensibilidade mostrou que os números da curva (CN2), ALPHA-BNK e CH-K2 são os três principais parâmetros mais sensíveis. Os valores de R2 e Nash-Sutcliffe Efficiency (NSE) foram usados para examinar o desempenho do modelo. Os resultados indicam 0,84 e 0,80 para R2 e 0,65 e 0,54 para NSE durante a calibração e validação, respectivamente. O escoamento superficial médio anual na bacia hidrográfica foi de 774,13 mm. Mudanças na precipitação explicaram 89% da variação no escoamento superficial, pois mais de 89% da precipitação da bacia foi convertida em escoamento superficial. As sub-bacias 11, 23 e 5 foram as que mais contribuíram para os fluxos superficiais anuais da Bacia do Rio Didessa. Palavras-chave: Tipo de solo. Análise sensitiva. Fluxo de córregos. Swat-Cup. Bacia Superior do Rio.


Author(s):  
A Labbaci ◽  
S Marghadi ◽  
S Laaribya ◽  
S Moukrim

Water erosion causes significant economic losses linked mainly to the silting up of dams and losses in soil productivity, these consequences will increase if soil and water conservation actions associated with development actions are not undertaken. The present work aims to evaluate the water erosion in the basin of the Beni Boufrah located in the Northern part of Morocco. The hierarchy of this basin in plot according to the degrees and the tendencies of the erosion was made using the qualitative PAP/CAR approach (Programme d’Actions Prioritaires/Centre d’Activités Regionales) which is based on the integration of the factors influencing the water erosion, such as the slope, lithology and/or pedology, vegetation cover and land use. This work was conducted in three stages, the first one being predictive based on the analysis of the natural factors influencing water erosion and the processing of databases of developed maps. The second so-called descriptive stage is based on the mapping of different forms and processes of soil loss that occur in the study area. The last step, it allows the integration and the combination of the results of the two previous steps. Its purpose is to provide a precise cartographic product that reflects the reality of the state of soil degradation and the future evolution of erosion. The consolidated erosion map shows that more than half of the basin area (53%) is affected by medium-level erosion, 13% is affected by high erosion level, and 15 % is affected by low-level water erosion. Low-intensity erosion occurs along the river in areas where the slope and lithology favour runoff. The trend map is the final result of the integration phase, it describes erosion trends in the different parts of the basin and is, therefore, a tool to guide decisions on land use planning and tillage methods to limit the risk of water erosion in the basin. Keywords: Oued Beni Boufrah, water erosion, PAP/CAR, erosive states, erosion trend.


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