scholarly journals Avaliação de Impactos de Mudanças no Uso e Manejo do Solo Sobre as Vazões da Bacia Hidrográfica do Ribeirão José Pereira, Utilizando o Modelo Swat.

2021 ◽  
Vol 14 (2) ◽  
pp. 619
Author(s):  
Filipe Otávio Passos ◽  
Benedito Cláudio Da Silva ◽  
Fernando Das Graças Braga da Silva

Diversos processos naturais podem causar mudanças nos fluxos hidrológicos dentro de bacias hidrográficas, sendo estas ainda mais afetadas devido a ações antrópicas que mudem as suas características físicas, principalmente, o tipo e o uso do solo. Neste contexto, este trabalho apresenta uma calibração de um modelo de transformação chuva x vazão e posterior simulação para a estimativa das vazões na bacia hidrográfica do ribeirão José Pereira, em Itajubá, sul de Minas Gerais, utilizando o modelo distribuído Soil and Water Assessment Tool (Swat). Foram gerados cinco cenários de uso e ocupação do solo, que foram idealizados a partir de características observadas na bacia ou de tendências futuras de ocupação, a saber, o cenário do estado atual, de manejo do solo, de recuperação das áreas de preservação permanente (APPs) de margens de rios, de substituição total por floresta e de crescimento urbano. Os resultados indicam que o modelo Swat pode ser utilizado na simulação das componentes hidrológicas de bacias hidrográficas de pequeno porte, e ainda que o manejo agrícola e o reflorestamento da bacia são mais eficientes na diminuição do escoamento superficial do que a recuperação das APPs, chegando a uma diminuição de aproximadamente 40% nas vazões máximas simuladas. Impact Assessment of Changes in Land Use and Management on the Losses of the Water Source of the José Pereira Stream, Using the SWAT Model A B S T R A C TSeveral natural processes can cause changes in hydrological flows within hydrographic basins, which are even more affected due to anthropic actions that change their physical characteristics, mainly, the type and use of the soil. In this context, this work carries out an analysis of the impact on the flows of a small-scale hydrographic basin (River José Pereira) due to changes in land use and occupation, using the distributed model Soil and Water Assessment Tool (SWAT). Five land use and occupation scenarios were generated, which were designed based on characteristics observed in the basin or future occupation trends, namely, the current state scenario, soil management, recovery of permanent preservation areas (APPs) of river banks, total replacement by forest and urban growth. The results indicate that the SWAT model can be used in the simulation of the hydrological components of small hydrographic basins, and that agricultural management and reforestation of the basin are more efficient in reducing runoff than the recovery of APPs, reaching a decrease of approximately 40% in the maximum simulated flows.Keywords: hydrological modeling, rainfall, SWAT, land use and occupation.

2013 ◽  
Vol 7 (3) ◽  
pp. 252-257

The subject of this article is the estimation of quantitative (hydrological) and qualitative parameters in the catchment of Ronnea (1800 Km2, located in south western Sweden) through the application of the Soil and Water Assessment Tool (SWAT). SWAT is a river basin model that was developed for the U.S.D.A. Agricultural Research Service, by the Blackland Research Center in Texas. The SWAT model is a widely known tool that has been used in several cases world-wide. It has the ability to predict the impact of land management practices on water, sediment and agricultural chemical yield in large complex watersheds. The present work investigates certain capabilities of the SWAT model which have not identified up to now. More in specific, the main targets of the work carried out are the following: • Identification of the existing hydrological and qualitative conditions • Preparation - Processing of data required to be used as input data of the model • Hydrological calibration - validation of the model, in 7 subbasins of the Catchment of Ronnea • Estimation and evaluation of the simulated qualitative parameters of the model All available data were offered by the relevant Institutes of Sweden, in the framework of the European program EUROHARP. The existing conditions in the catchment of Ronnea, are described in detail including topography, land uses, soil types, pollution sources, agricultural management practices, precipitation, temperature, wind speed, humidity, solar radiation as well as observed discharges and Nitrogen and Phosphorus substances concentrations. Most of the above data were used as input data for the application of SWAT model. Adequate methods were also used to complete missing values in time series and estimate additional parameters (such as soil parameters) required by the model. Hydrological calibration and validation took place for each outlet of the 7 subbasins of Ronnea catchment in an annual, monthly and daily step. The calibration was achieved by estimating parameters related to ground water movement and evaluating convergence between simulated and observed discharges by using mainly the Nash & Sutcliffe coefficient (NTD). Through the sensitivity analysis, main parameters of the hydrological simulation, were detected. According to the outputs of the SWAT model, the water balance of Ronnea catchment was also estimated. Hydrological calibration and validation is generally considered sufficient in an annual and monthly step. Hydrological calibration – validation in daily step, generally does not lead to high values of the NTD indicator. However, when compared to results obtained by the use of SWAT in Greece, a relatively high value of NTD is achieved in one subbasin. Finally, a comparison between the simulated and observed concentrations of total Phosphorus and Nitrogen was carried out.


2020 ◽  
Vol 13 (2) ◽  
pp. 576
Author(s):  
Letícia Lopes Martins ◽  
Wander Araújo Martins ◽  
Jener Fernando Leite De Moraes ◽  
Mário José Pedro Júnior ◽  
Isabella Clerici De Maria

A dificuldade na gestão de recursos hídricos aliada à dinâmica do uso e ocupação do solo em bacias hidrográficas agrícolas são fatores relevantes para a conservação da água e solo. A gestão de bacias hidrográficas, bem como o monitoramento de cenários de expansão agrícola e mudança no uso do solo, podem se beneficiar de ferramentas de modelagem hidrossedimentológica, como o SWAT (Soil and Water Assessment Tool). Entretanto, para que os resultados obtidos sejam confiáveis, os modelos precisam ser calibrados. Objetivou-se, neste trabalho, calibrar e validar o modelo SWAT, para a variável vazão, tendo como base a bacia hidrográfica do Ribeirão do Pinhal, Limeira -São Paulo, que se caracteriza pela expansão da cana-de-açúcar sobre áreas citrícolas. Dados de vazão de um posto fluviométrico localizado no exutório da bacia foram utilizados para a calibração e validação, a partir de séries temporais diferentes.  Utilizou-se o software QSWAT para a simulação hidrológica e o SWAT-CUP para a calibração e validação do modelo. O modelo foi calibrado e validado resultando nos seguintes índices estatísticos NSE=0,64; PBIAS=15,2 e RSR=0,60 para calibração e NSE=0,68 PBIAS=-2,8 e RSR=0,56 para a validação. O ajuste de parâmetros do SWAT (USLE_P, USLE_C, CN2) e do calendário de operações da cana-de-açúcar em acordo com a situação real da bacia foi necessário para a calibração do modelo. Os resultados indicam que o modelo SWAT subestima as vazões extremas, no entanto, dentro de faixa aceitável. O SWAT, após a calibração, pode ser utilizado na gestão de recursos hídricos na bacia do Ribeirão do Pinhal.Hydrological calibration of the SWAT model in a watershed characterized by the expansion of sugarcane cultivationA B S T R A C TThe difficulty in water resources management combined with the dynamics of land use and occupation in agricultural watersheds are relevant factors for water and soil conservation. River basin management, as well as monitoring scenarios of agricultural expansion and land-use change, can benefit from hydrossedimentological modeling tools such as the SWAT (Soil and Water Assessment Tool). However, for the results to be reliable, the models must be calibrated. The objective of this study was to calibrate and validate the SWAT model for the flow variable, based on the Ribeirão do Pinhal watershed, Limeira-São Paulo, which is characterized by the expansion of sugarcane over citrus areas. Flow data from a fluviometric station located in the basin's outfall were used for calibration and validation from different time series. QSWAT software was used for hydrological simulation and SWAT-CUP for model calibration and validation. The model was calibrated and validated resulting in the following statistical indices NSE = 0.64; PBIAS = 15.2 and RSR = 0.60 for calibration and NSE = 0.68 PBIAS = -2.8 and RSR = 0.56 for validation. Adjustment of SWAT parameters (USLE_P, USLE_C, and CN2) and the sugarcane operation schedule according to the actual basin situation was necessary for model calibration. The results indicate that the SWAT model underestimates the extreme flow rates, however, within an acceptable range. After calibration, the SWAT can be used to manage water resources in the Ribeirão do Pinhal basin.Keywords: Hydrologic simulation; land use; flow rate.


Author(s):  
Timketa Adula Duguma

Abstract: In this study the semi-distributed model SWAT (Soil and Water Assessment Tool), were applied to evaluate stream flow of Didessa sub basin, which is one of the major sub basins in Abay river basin of Ethiopia. The study evaluated the quality of observed meteorological and hydrological data, established SWAT hydrological model, identified the most sensitive parameters, evaluated the best distribution for flow and developed peak flow for major tributary in the sub basin. The result indicated that the SWAT model developed for the sub basin evaluated at multi hydro-gauging stations and its performance certain with the statistical measures, coefficient about determination (R2) and also Nash coefficient (NS) with values ranging 0.62 to 0.8 and 0.6 to 0.8 respectively at daily time scale. The values of R2 and NS increases at monthly time scale and found ranging 0.75 to 0.92 and 0.71 to 0.91 respectively. Sensitivity analysis is performed to identify parameters those were most sensitive for the sub basin. CN2, GWQMN, CH_K, ALPHA_BNK and LAT_TIME are the most sensitive parameters in the sub basin. Finally, the peak flow for 2-10000 returns periods were determined after the best probability distribution is identified in EasyFit computer program.


2020 ◽  
Vol 14 (2) ◽  
pp. 154-161
Author(s):  
Diah Ainunisa ◽  
◽  
Gusfan Halik ◽  
Wiwik Yunarni Widiarti ◽  
◽  
...  

Population growth is one of the causes of land-use change that can increase runoff. Tanggul watershed is one of the watersheds which often overflows during the rainy season. This study purpose to analyze the effect of land-use changes on runoff in Tanggul watershed using SWAT (Soil and Water Assessment Tool) model. To make sure the performance of SWAT model calibration and classified by the value of NSE and R2. The result of calibration included in a good category and validation included in a very good category. This study was modeling forest land-use change in 2004-2017 to determine the effect of land-use change on runoff. The result in this model of forest land-use change can increase runoff.


2020 ◽  
Author(s):  
Jihui Fan ◽  
Majid Galoie ◽  
Artemis Motamedi ◽  
Jing Huang

Abstract The main objective of this paper is to evaluate the impact of land cover resolution, in comparison with the digital elevation model (DEM) resolution, on hydrological modeling outputs. Three different basins in the various resolutions of DEM (12.5, 25, 50, 100, 500 and 1,000 m) and land-use maps (250, 1,000 and 2,500 m) were collected in this study, and the hydrological modeling process was performed using the Soil and Water Assessment Tool (SWAT) model. The soil type resolution was 1,000 m for all basins, and the runoff modeling was done based on the Soil Conservation Service Curve Number (SCS-CN) method. The final model outputs showed that the DEM cell size variations affect significantly the topographical characteristics of a catchment such as area, mean slope, river network and time to concentration which alter the flood modeling outputs especially in hilly watersheds (mean slope more than 15%) up to 15% for a DEM cell size of 1,000 m in comparison to 12.5 m. Also, the resolution and spatial distribution of land cover maps which directly specify SCS-CN values, can change the output simulated runoff results up to 49% for a land cover cell size of 2,500 m in comparison to 250 m. These results indicated that the quality of the land cover map is more important than the quality of DEM in hydrological modeling. Also, the results showed that for an identical land-use cell size, the differences between model outputs using DEM cell sizes less than 100 m were not very significant. Furthermore, in all models by increasing the DEM cell size, the simulated runoff depth was decreased.


2019 ◽  
Vol 12 (5) ◽  
pp. 1746
Author(s):  
Rafael Adriano de Castro Adriano de Castro ◽  
Elias Machado

O modelo Soil and Water Assessment Tool (SWAT) é amplamente utilizado para predizer o impacto das alterações no uso e no manejo do solo, entre outros, é extremamente sensível à qualidade dos dados de entrada.  Assim, antes da simulação é necessário que se realize uma análise de sensibilidade de tal forma que se possa dar ênfase maior à aquisição e refinamento de determinados dados, diminuir as incertezas e aumentar a confiança nos resultados gerados. Os resultados simulados na bacia do Rio das Pedras – Guarapuava, foram realizadas a análise de sensibilidade e a calibração do modelo SWAT. Após a calibração do modelo os resultados do Índice de Nash & Sutcliffe alterado (COE), do percentual de tendência (PBIAS), e o coeficiente de determinação (R²) foram, respectivamente, 0,69, -0,5 e 0,7, indicando bom ajuste entre a vazão média mensal da bacia Rio das Pedras simulada pelo modelo SWAT em relação aos dados observados.  Sensitivity analysis of hydrological parameters in the Rio das Pedras basin - Guarapuava-PR A B S T R A C TThe SWAT model is widely used to predict the impact of changes in land use and management, among others, is extremely sensitive to the quality of input data. Thus, prior to the simulation, it is necessary to perform a sensitivity analysis in such a way that greater emphasis can be placed on the acquisition and refinement of certain data, decrease uncertainties and increase confidence in the results generated. The simulated results in the Rio das Pedras - Guarapuava basin, were performed the sensitivity analysis and calibration of the SWAT model. After the calibration of the model, the results of the modified Nash & Sutcliffe Index (COE), percentage of trend (PBIAS), and coefficient of determination (R²) were, respectively, 0.69, -0.5 and 0.7, Indicating a good fit between the average monthly flow of the Rio das Pedras basin simulated by the SWAT model in relation to the observed data. 


Author(s):  
N. Hari ◽  
A. Mani ◽  
H. V. Hema Kumar ◽  
V. Srinivasa Rao ◽  
L. Edukondalu

The present study was conducted to investigate the impact of land use cover change on water resources availability in Gundlakamma Subbasin. The Gundlakamma subbasin is predominantly agricultural based and Gundlakamma is a seasonal river. Hence, a study has been conducted to simulate the availability of water resources in the subbasin using SWAT (Soil and Water Assessment Tool) model. The database was generated like DEM, soil map and land use/cover using the secondary data and field survey. The SWAT model was calibrated three years (2010-2012) and validated with four years (2013-2016) with the observed discharges from reservoir outflow. The values of NSE and R2 was found as 0.79 and 0.87 during calibration, 0.65 and 0.72, respectively during validation. The modelled values showed reasonably good agreement with the observed values of reservoir outflow, both during calibration and validation periods. The reservoir outflow in the subbasin was quantified under the change land use conditions.


2021 ◽  
Author(s):  
Firas Alsilibe ◽  
Katalin Bene

Abstract In watershed modeling research, it is practical to subdivide a watershed into smaller units or sub-watersheds for modeling purposes. The ability of a model to simulate the watershed system depends on how well watershed processes are represented by the model and how well the watershed system is described by model input. This study is conducted to evaluate the impact of watershed subdivision and different weather input datasets on streamflow simulations using the soil and water assessment tool model. For this purpose, Cuhai-Bakonyér watershed was chosen as a study area. Two climate databases and four subdivision variations levels were evaluated. The model streamflow predictions slightly effected by subdivision impact. The climate datasets showed significant differences in streamflow predictions.


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