A Review of SWAT Model Application in Africa

The soil and water assessment tool (SWAT) is a well-known hydrological modeling tool that has been applied in various hydrologic and environmental simulations. A total of 206 studies over a 15-year period (2005–2019) were identified from various peer-reviewed scientific journals listed on the SWAT website database, which is supported by the Centre for Agricultural and Rural Development (CARD). These studies were categorized into five areas, namely applications considering: water resources and streamflow, erosion and sedimentation, land-use management and agricultural-related contexts, climate-change contexts, and model parameterization and dataset inputs. Water resources studies were applied to understand hydrological processes and responses in various river basins. Land-use and agriculture-related context studies mainly analyzed impacts and mitigation measures on the environment and provided insights into better environmental management. Erosion and sedimentation studies using the SWAT model were done to quantify sediment yield and evaluate soil conservation measures. Climate-change context studies mainly demonstrated streamflow sensitivity to weather changes. The model parameterization studies highlighted parameter selection in streamflow analysis, model improvements, and basin scale calibrations. Dataset inputs mainly compared simulations with rain-gauge and global rainfall data sources. The challenges and advantages of the SWAT model’s applications, which range from data availability and prediction uncertainties to the model’s capability in various applications, are highlighted. Discussions on considerations for future simulations such as data sharing, and potential for better future analysis are also highlighted. Increased efforts in local data availability and a multidimensional approach in future simulations are recommended.

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Quantitative Attribution of Runoff Attenuation to Climate Change and Human Activity in Typical Mountainous Areas: An Enlightenment to Water Resource Sustainable Utilization and Management in North China

Sustainability ◽

10.3390/su122410395 ◽

2020 ◽

Vol 12 (24) ◽

pp. 10395

Author(s):

Yufei Jiao ◽

Jia Liu ◽

Chuanzhe Li ◽

Wei Wang ◽

Fuliang Yu ◽

...

Keyword(s):

Climate Change ◽

Land Use ◽

Water Resources ◽

Water Resource ◽

Human Activities ◽

North China ◽

Assessment Tool ◽

Swat Model ◽

Data Series ◽

Sustainable Utilization

The influence of climate change and human activities on hydrological elements has increased along with increasing dependence on water resources. Therefore, quantitative attribution of hydrological elements has received wide attention. In this study, the double mass curve (DMC) is used to assess the abrupt change point of the hydrological data series, based on which the periods with/without large-scale human activities causing runoff attenuation are separated. The land use transition matrix is then employed to analyze the land use types at different historical stages, and the sensitivities of the runoff attenuation to different land use/cover change (LUCC) categories are quantified. A soil and water assessment tool (SWAT) model that considers the underlying surface is constructed with six designed scenarios of different climate and LUCC conditions. Taking three typical mountainous basins in North China as the study area, the quantitative contributions of climate change and human activities to the water resources are identified. The results of the study have brought enlightenment to the water resource sustainable utilization and management in North China, and the methodologies can be transferred to runoff attribution analysis in water shortage areas.

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Analyzing the impacts of climate and land use changes on the water quality in the 3S river basin

Science and Technology Development Journal - Natural Sciences ◽

10.32508/stdjns.v2i2.745 ◽

2019 ◽

Vol 2 (2) ◽

pp. 125-131

Author(s):

Loi Thi Pham ◽

Khoi Nguyen Dao

Keyword(s):

Climate Change ◽

Water Quality ◽

Land Use ◽

Water Resources ◽

Land Use Change ◽

River Basin ◽

Water Resource Management ◽

Hydrological Modeling ◽

Swat Model ◽

The Impact

Assessing water resources under the influence of environmental change have gained attentions of scientists. The objective of this study was to analyze the impacts of land use change and climate change on water resources in terms quantity and quality in the 3S basin in the period 1981–2008 by using hydrological modeling (SWAT model). The results showed that streamflow and water quality (TSS, T-N, and T-P) tend to increase under individual and combined effects of climate change and land use change. In addition, the impact of land use change on the flow was smaller than the climate change impact. However, water balance components and water quality were equally affected by two factors of climate change and land use change. In general, the results of this study could serve as a reference for water resource management and planning in the river basin.

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Evaluating and Predicting the Effects of Land Use Changes on Hydrology in Wami River Basin, Tanzania

Hydrology ◽

10.3390/hydrology7010017 ◽

2020 ◽

Vol 7 (1) ◽

pp. 17 ◽

Cited By ~ 2

Author(s):

Sekela Twisa ◽

Shija Kazumba ◽

Mathew Kurian ◽

Manfred F. Buchroithner

Keyword(s):

Land Use ◽

Water Resources ◽

Assessment Tool ◽

Swat Model ◽

Land Use Changes ◽

Management Strategies ◽

River System ◽

Least Squares Regression ◽

Natural Forests ◽

The Impact

Understanding the variation in the hydrological response of a basin associated with land use changes is essential for developing management strategies for water resources. The impact of hydrological changes caused by expected land use changes may be severe for the Wami river system, given its role as a crucial area for water, providing food and livelihoods. The objective of this study is to examine the influence of land use changes on various elements of the hydrological processes of the basin. Hybrid classification, which includes unsupervised and supervised classification techniques, is used to process the images (2000 and 2016), while CA–Markov chain analysis is used to forecast and simulate the 2032 land use state. In the current study, a combined approach—including a Soil and Water Assessment Tool (SWAT) model and Partial Least Squares Regression (PLSR)—is used to explore the influences of individual land use classes on fluctuations in the hydrological components. From the study, it is evident that land use has changed across the basin since 2000 (which is expected to continue in 2032), as well as that the hydrological effects caused by land use changes were observed. It has been found that the major land use changes that affected hydrology components in the basin were expansion of cultivation land, built-up area and grassland, and decline in natural forests and woodland during the study period. These findings provide baseline information for decision-makers and stakeholders concerning land and water resources for better planning and management decisions in the basin resources’ use.

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Predicting hydrologic responses to climate changes in highly glacierized and mountainous region Upper Indus Basin

Royal Society Open Science ◽

10.1098/rsos.191957 ◽

2020 ◽

Vol 7 (8) ◽

pp. 191957 ◽

Cited By ~ 2

Author(s):

Muhammad Izhar Shah ◽

Asif Khan ◽

Tahir Ali Akbar ◽

Quazi K. Hassan ◽

Asim Jahangir Khan ◽

...

Keyword(s):

Climate Change ◽

Water Resources ◽

Climate Model ◽

Assessment Tool ◽

Model Simulation ◽

Global Climate ◽

Meteorological Data ◽

Swat Model ◽

Indus Basin ◽

Upper Indus Basin

The Upper Indus Basin (UIB) is a major source of supplying water to different areas because of snow and glaciers melt and is also enduring the regional impacts of global climate change. The expected changes in temperature, precipitation and snowmelt could be reasons for further escalation of the problem. Therefore, estimation of hydrological processes is critical for UIB. The objectives of this paper were to estimate the impacts of climate change on water resources and future projection for surface water under different climatic scenarios using soil and water assessment tool (SWAT). The methodology includes: (i) development of SWAT model using land cover, soil and meteorological data; (ii) calibration of the model using daily flow data from 1978 to 1993; (iii) model validation for the time 1994–2003; (iv) bias correction of regional climate model (RCM), and (v) utilization of bias-corrected RCM for future assessment under representative concentration pathways RCP4.5 and RCP8.5 for mid (2041–2070) and late century (2071–2100). The results of the study revealed a strong correlation between simulated and observed flow with R 2 and Nash–Sutcliff efficiency (NSE) equal to 0.85 each for daily flow. For validation, R 2 and NSE were found to be 0.84 and 0.80, respectively. Compared to baseline period (1976–2005), the result of RCM showed an increase in temperature ranging from 2.36°C to 3.50°C and 2.92°C to 5.23°C for RCP4.5 and RCP8.5 respectively, till the end of the twenty-first century. Likewise, the increase in annual average precipitation is 2.4% to 2.5% and 6.0% to 4.6% (mid to late century) under RCP4.5 and RCP8.5, respectively. The model simulation results for RCP4.5 showed increase in flow by 19.24% and 16.78% for mid and late century, respectively. For RCP8.5, the increase in flow is 20.13% and 15.86% during mid and late century, respectively. The model was more sensitive towards available moisture and snowmelt parameters. Thus, SWAT model could be used as effective tool for climate change valuation and for sustainable management of water resources in future.

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Assessing Impacts of Climate Variability and Reforestation Activities on Water Resources in the Headwaters of the Segura River Basin (SE Spain)

Sustainability ◽

10.3390/su10093277 ◽

2018 ◽

Vol 10 (9) ◽

pp. 3277 ◽

Cited By ~ 9

Author(s):

Javier Senent-Aparicio ◽

Sitian Liu ◽

Julio Pérez-Sánchez ◽

Adrián López-Ballesteros ◽

Patricia Jimeno-Sáez

Keyword(s):

Climate Change ◽

Land Use ◽

Water Resources ◽

River Basin ◽

Assessment Tool ◽

Forest Area ◽

Se Spain ◽

Monthly Streamflow ◽

Agricultural Areas ◽

Water Assessment

Climate change and the land-use and land-cover changes (LULC) resulting from anthropic activity are important factors in the degradation of an ecosystem and in the availability of a basin’s water resources. To know how these activities affect the quantity of the water resources of basins, such as the Segura River Basin, is of vital importance. In this work, the Soil and Water Assessment Tool (SWAT) was used for the study of the abovementioned impacts. The model was validated by obtaining a Nash–Sutcliffe efficiency (NSE) of 0.88 and a percent bias (PBIAS) of 17.23%, indicating that SWAT accurately replicated monthly streamflow. Next, land-use maps for the years of 1956 and 2007 were used to establish a series of scenarios that allowed us to evaluate the effects of these activities on both joint and individual water resources. A reforestation plan applied in the basin during the 1970s caused that the forest area had almost doubled, whereas the agricultural areas and shrubland had been reduced by one-third. These modifications, together with the effect of climate change, have led to a decrease of 26.3% in the quantity of generated water resources, not only due to climate change but also due to the increase in forest area.

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Calibração hidrológica do modelo SWAT em bacia hidrográfica caracterizada pela expansão do cultivo da cana-de-açúcar

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v13.2.p576-594 ◽

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

Keyword(s):

Land Use ◽

Water Resources ◽

Model Calibration ◽

Assessment Tool ◽

Swat Model ◽

Sao Paulo ◽

São Paulo ◽

Calibration And Validation ◽

Water Assessment ◽

Soil And Water

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.

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Improved SWAT vegetation growth module for tropical ecosystem

10.5194/hess-2017-104 ◽

2017 ◽

Cited By ~ 2

Author(s):

Tadesse Alemayehu ◽

Ann van Griensven ◽

Willy Bauwens

Keyword(s):

Climate Change ◽

Land Use ◽

Soil Moisture ◽

Management Practices ◽

Assessment Tool ◽

Swat Model ◽

Evergreen Forest ◽

Tropical Ecosystem ◽

Area Index ◽

Vegetation Growth

Abstract. The Soil and Water Assessment Tool (SWAT) is a globally applied river basin eco-hydrological simulator in a wide spectrum of studies, ranging from land use change and climate change impacts studies to research for the development of best water management practices. However, SWAT has limitations in simulating the seasonal growth cycles for trees and perennial vegetation in tropics, where the major plant growth controlling factor is the rainfall (via soil moisture) rather than temperature. Our goal is to improve the vegetation growth module of the SWAT model for simulating the vegetation parameters such as the leaf area index (LAI) for tropics. Therefore, we present a modified SWAT version for the tropics (SWAT-T) that uses of a simple but robust soil moisture index (SMI) – a quotient of the rainfall (P) and reference evapotranspiration (PET) – to initiate a new growing season after a defined dry season. Our results for the Mara Basin (Kenya/Tanzania) show that the SWAT-T simulated LAI corresponds well with the Moderate Resolution Imaging Spectroradiometer (MODIS) LAI for evergreen forest, savanna grassland and shrubs, indicating that the SMI is a reliable proxy to dynamically initiate a new growing cycle. The water balance components (evapotranspiration and flow) simulated by the SWAT-T exhibit a good agreement with remote sensing-based evapotranspiration (RS-ET) and observed flow. The SWAT-T simulator with the proposed improved vegetation growth module for tropical ecosystem could be a robust tool for several applications including land use and climate change impact studies.

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Impact of Climate Change on the Hydrology of the Upper Awash River Basin, Ethiopia

Hydrology ◽

10.3390/hydrology9010003 ◽

2021 ◽

Vol 9 (1) ◽

pp. 3

Author(s):

Nega Chalie Emiru ◽

John Walker Recha ◽

Julian R. Thompson ◽

Abrham Belay ◽

Ermias Aynekulu ◽

...

Keyword(s):

Climate Change ◽

Assessment Tool ◽

Addis Ababa ◽

Swat Model ◽

Hydrological Drought ◽

Global Climate Models ◽

Mitigation Measures ◽

Maximum Temperature ◽

Mean Annual Precipitation ◽

Trend Test

This study investigated the impacts of climate change on the hydrology of the Upper Awash Basin, Ethiopia. A soil and water assessment tool (SWAT) model was calibrated and validated against observed streamflow using SWAT CUP. The Mann–Kendall trend test (MK) was used to assess climate trends. Meteorological drought (SPEI) and hydrological drought (SDI) were also investigated. Based on the ensemble mean of five global climate models (GCMs), projected increases in mean annual maximum temperature over the period 2015–2100 (compared with a 1983–2014 baseline) range from 1.16 to 1.73 °C, while increases in minimum temperature range between 0.79 and 2.53 °C. Increases in mean annual precipitation range from 1.8% at Addis Ababa to 45.5% over the Hombole area. High streamflow (Q5) declines at all stations except Ginchi. Low flows (Q90) also decline with Q90 equaling 0 m3s−1 (i.e., 100% reduction) at some gauging stations (Akaki and Hombole) for individual GCMs. The SPEI confirmed a significant drought trend in the past, while the frequency and severity of drought will increase in the future. The basin experienced conditions that varied from modest dry periods to a very severe hydrological drought between 1986 and 2005. The projected SDI ranges from modestly dry to modestly wet conditions. Climate change in the basin would enhance seasonal variations in hydrological conditions. Both precipitation and streamflow will decline in the wet seasons and increase in the dry seasons. These changes are likely to have an impact on agricultural activities and other human demands for water resources throughout the basin and will require the implementation of appropriate mitigation measures.

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Hydrologic Responses to Land Use Change in the Loess Plateau: Case Study in the Upper Fenhe River Watershed

Advances in Meteorology ◽

10.1155/2015/676030 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 4

Author(s):

Zhixiang Lu ◽

Songbing Zou ◽

Zuodong Qin ◽

Yonggang Yang ◽

Honglang Xiao ◽

...

Keyword(s):

Remote Sensing ◽

Land Use ◽

Loess Plateau ◽

Hydrological Modeling ◽

Swat Model ◽

Water Yield ◽

The Loess Plateau ◽

River Watershed ◽

Lulc Changes ◽

Basin Scale

We applied an integrated approach to investigate the impacts of land use and land cover (LULC) changes on hydrology at different scales in the Loess Plateau of China. Hydrological modeling was conducted for the LULC maps from remote sensing images at two times in the Upper Fenhe River watershed using the SWAT model. The main LULC changes in this watershed from 1995 to 2010 were the transformation of farmland into forests, grassland, and built-up land. The simulation results showed that forested land contributed more than any other LULC class to water yield, but built-up land had most impact due to small initial loss and infiltration. At basin scale, a comparison of the simulated hydrological components of two LULC maps showed that there were slight increases in average annual potential evapotranspiration, actual evapotranspiration, and water yield, but soil water decreased, between the two intervals. In subbasins, obvious LULC changes did not have clear impacts on hydrology, and the impacts may be affected by precipitation conditions. By linking a hydrological model to remote sensing image analysis, our approach of quantifying the impacts of LULC changes on hydrology at different scales provide quantitative information for stakeholders in making decisions for land and water resource management.

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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.

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v14.2.p619-633 ◽

2021 ◽

Vol 14 (2) ◽

pp. 619

Author(s):

Filipe Otávio Passos ◽

Benedito Cláudio Da Silva ◽

Fernando Das Graças Braga da Silva

Keyword(s):

Land Use ◽

Hydrological Modeling ◽

Assessment Tool ◽

Swat Model ◽

Water Source ◽

Distributed Model ◽

Small Scale ◽

The Impact ◽

Water Assessment ◽

Soil And Water

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.

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