scholarly journals Modelling Transport of Nitrogen Compounds in Geita Wetland along Mtakuja River

2018 ◽  
Vol 37 (2) ◽  
pp. 89-106
Author(s):  
Ezrael J. Massawe ◽  
Richard Kimwaga ◽  
Fredrick Mwanuzi
Keyword(s):  
Land Use ◽  
Management Practices ◽  
Assessment Tool ◽  
Swat Model ◽  
Nitrogen Loading ◽  
Model Parameters ◽  
Nitrogen Compounds ◽  
Land Use And Management ◽  
The Impact ◽  
Monitoring Stations

The impacts of excessive nitrogen loading to streams in a watershed occur in the receiving waters such as rivers at the outlet of the watershed. To quantify the impacts of land use and management practices on the nitrogen loading at the watershed outlet, simulation models are needed that can both predict the nitrogen loading at the edge of individual fields and predict the fate of nitrogen as it moves through the river network to the watershed outlet. This paper presents the results of a model analysis for describing the processes governing transformations and transport of nitrogen compounds (NO3-N and NH4-N) through Mtakuja River in the Geita wetland. The model was made in Soil and Water Assessment Tool (SWAT), a watershed model developed to assess the impact of land management practices on water, sediment and agricultural chemical yields with varying soils, land use and management conditions. Two monitoring stations namely MTSP1 and MTSP2 were established along Mtakuja River. A set of SWAT model inputs representative of the water conditions was collected from the established monitoring stations. The model was calibrated and validated for the prediction of flow and nitrogen compounds (NO3-N and NH4-N) transport, against a set of measured mean monthly monitoring data. Sensitive model parameters were adjusted within their feasible ranges during calibration to minimize model prediction errors. At the gauging station MTSP2, the calibration results showed that the model predicted mean monthly flow within 18% of the measured mean monthly flow with the r2 coefficient and Nash-Sutcliffe (NSE) were 0.84 and 0.82, respectively. At the water quality monitoring station MTSP2, the calibration results showed the model predicted nitrogen compounds (NO3-N and NH4-N) loadings within 21% and 23% of their respective measured mean monthly loadings. The mean monthly comparisons of r 2 values for nitrogen compounds ranged from 0.77 to 0.81 while the Nash-Sutcliffe Efficiency (NSE) values were between 0.72 and 0.73. The model results and field measurements demonstrated that about 70% of the annual nitrogen compounds loadings which would otherwise reach Lake Victoria are retained in the wetland. The Mtakuja river model can therefore be used for prediction of nitrogen compounds (NO3-N and NH4-N) transformation processes in the Geita wetland.

LUU CHECKER: A Web-based Tool to Incorporate Emerging LUs in the SWAT Model

2019 ◽  
Vol 35 (5) ◽  
pp. 723-731 ◽  
Author(s):  
Gurdeep Singh ◽  
Dharmendra Saraswat ◽  
Naresh Pai ◽  
Benjamin Hancock
Keyword(s):  
Land Use ◽  
Management Practices ◽  
Assessment Tool ◽  
Urban Forest ◽  
Swat Model ◽  
Land Use Changes ◽  
Web Based ◽  
Large Size ◽  
Hydrologic Response Unit ◽  
User Friendly

Abstract. Standard practice of setting up Soil and Water Assessment Tool (SWAT) involves use of a single land use (LU) layer under the assumption that no change takes place in LU condition irrespective of the length of simulation period. This assumption leads to erroneous conclusions about efficacy of management practices in those watersheds where land use changes (LUCs) (e.g. agriculture to urban, forest to agriculture etc.) occur during the simulation period. To overcome this limitation, we have developed a user-friendly, web-based tool named LUU Checker that helps create a composite LU layer by integrating multiple years of LU layers available in watersheds of interest. The results show that the use of composite LU layer for hydrologic response unit (HRU) delineation in 2474-km2 L’Anguile River Watershed in Arkansas was able to capture changed LU at subbasin level by using LU data available in the year 1999 and 2006, respectively. The web-based tool is applicable for large size watersheds and is accessible to multiple users from anywhere in the world. Keywords: Land use, Web-based tool, SWAT, LUU Checker.

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

Hydrology ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 17 ◽  
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.

scholarly journals Application of the SWAT (Soil and Water Assessment Tool) model in the Ronnea catchment of Sweden

2013 ◽  
Vol 7 (3) ◽  
pp. 252-257
Keyword(s):  
Input Data ◽  
Management Practices ◽  
Assessment Tool ◽  
Swat Model ◽  
Soil Parameters ◽  
Daily Step ◽  
Calibration And Validation ◽  
The Impact ◽  
Water Assessment ◽  
Soil And Water

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.

scholarly journals Assessing the Impact of Best Management Practices in a Highly Anthropogenic and Ungauged Watershed Using the SWAT Model: A Case Study in the El Beal Watershed (Southeast Spain)

Agronomy ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 576 ◽  
Author(s):  
Adrián López-Ballesteros ◽  
Javier Senent-Aparicio ◽  
Raghavan Srinivasan ◽  
Julio Pérez-Sánchez
Keyword(s):  
Coastal Lagoon ◽  
Best Management Practices ◽  
Management Practices ◽  
Assessment Tool ◽  
Swat Model ◽  
Fertilizer Application ◽  
Coefficient Of Determination ◽  
Check Dam ◽  
Best Management ◽  
The Impact

Best management practices (BMPs) provide a feasible solution for non-point source pollution problems. High sediment and nutrient yields without retention control result in environmental deterioration of surrounding areas. In the present study, the soil and water assessment tool (SWAT) model was developed for El Beal watershed, an anthropogenic and ungauged basin located in the southeast of Spain that drains into a coastal lagoon of high environmental value. The effectiveness of five BMPs (contour planting, filter strips, reforestation, fertilizer application and check dam restoration) was quantified, both individually and in combination, to test their impact on sediment and nutrient reduction. For calibration and validation processes, actual evapotranspiration (AET) data obtained from a remote sensing dataset called Global Land Evaporation Amsterdam Model (GLEAM) were used. The SWAT model achieved good performance in the calibration period, with statistical values of 0.78 for Kling–Gupta efficiency (KGE), 0.81 for coefficient of determination (R2), 0.58 for Nash–Sutcliffe efficiency (NSE) and 3.9% for percent bias (PBIAS), as well as in the validation period (KGE = 0.67, R2 = 0.83, NS = 0.53 and PBIAS = −25.3%). The results show that check dam restoration is the most effective BMP with a reduction of 90% in sediment yield (S), 15% in total nitrogen (TN) and 22% in total phosphorus (TP) at the watershed scale, followed by reforestation (S = 27%, TN = 16% and TP = 20%). All effectiveness values improved when BMPs were assessed in combination. The outcome of this study could provide guidance for decision makers in developing possible solutions for environmental problems in a coastal lagoon.

scholarly journals Improved SWAT vegetation growth module for tropical ecosystem

2017 ◽  
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.

scholarly journals Assessment of MC&MCMC uncertainty analysis frameworks on SWAT model by focusing on future runoff prediction in a mountainous watershed via CMIP5 models

2019 ◽  
Vol 11 (4) ◽  
pp. 1811-1828
Author(s):  
Armin Ahmadi ◽  
Amirhosein Aghakhani Afshar ◽  
Vahid Nourani ◽  
Mohsen Pourreza-Bilondi ◽  
A. A. Besalatpour
Keyword(s):  
General Circulation ◽  
Assessment Tool ◽  
Swat Model ◽  
General Circulation Models ◽  
Cmip5 Models ◽  
Historical Period ◽  
Model Parameters ◽  
Runoff Simulation ◽  
Rcp Scenarios ◽  
The Impact

Abstract The river situation in a dry or semi-dry area is extremely affected by climate change and precipitation patterns. In this study, the impact of climate alteration on runoff in Kashafrood River Basin (KRB) in Iran was investigated using the Soil and Water Assessment Tool (SWAT) in historical and three future period times. The runoff was studied by MIROC-ESM and GFDL-ESM2G models as the outputs of general circulation models (GCMs) in the Coupled Model Intercomparison Project Phase 5 (CMIP5) by two representative concentration pathway (RCP) scenarios (RCP2.6 and RCP8.5). The DiffeRential Evolution Adaptive Metropolis (DREAM-ZS) was used to calibrate the hydrological model parameters in different sub-basins. Using DREAM-ZS algorithm, realistic values were obtained for the parameters related to runoff simulation in the SWAT model. In this area, results show that runoff in GFDL-ESM2G in both RCPs (2.6 and 8.5) in comparing future periods with the historical period is increased about 232–383% and in MIROC-ESM tends to increase around 87–292%. Furthermore, GFDL-ESM2G compared to MIROC-ESM in RCP2.6 (RCP8.5) in near, intermediate, and far future periods shows that the value of runoff increases 59.6% (23.0%), 100.2% (35.1%), and 42.5% (65.3%), respectively.

Canadian agricultural land-use and land management data for Kyoto reporting

2006 ◽  
Vol 86 (3) ◽  
pp. 431-439 ◽  
Author(s):  
T. Huffman ◽  
R. Ogston ◽  
T. Fisette ◽  
B. Daneshfar ◽  
P-Y. Gasser, L. White ◽  
...  
Keyword(s):  
Land Use ◽  
Land Management ◽  
Management Practices ◽  
Agricultural Land ◽  
Spatial Scales ◽  
Satellite Image ◽  
Data Sources ◽  
Land Use And Management ◽  
National Analysis ◽  
The Impact

The land use and management data requirements for assessing, monitoring and reporting on the impact of agricultural production practices on the environment, especially in a country as large as Canada, are considerable. In view of the fact that environmental assessments are a relatively new phenomenon, data collection activities targeted toward these needs are not widespread. As a result, we find it necessary to acquire and integrate a variety of data sources with differing time lines, spatial scales and sampling frameworks. This paper uses our current activities with respect to Kyoto reporting as a focus to present and discuss the types of data required and the spatial analysis and integration procedures being developed to provide them. The essential data for this activity include the area of crop and land use types, land use changes since 1990, farm and land management practices and biomass production. The spatial framework selected for national analysis is the Soil Landscapes of Canada, and the primary existing data sources are the Census of Agriculture, sample-derived yield estimates and satellite-based land cover products. These are supplemented with detailed, multi-season, multi-year satellite image interpretations conducted at an ecologically and statistically stratified sample of sites across the country. The use of these data in preparing an account of greenhouse gas sources and sinks identified a number of gaps and problems, and a brief outline of future work designed to improve the data inputs is presented. Key words: Kyoto reporting, data integration, land use and management, greenhouse gases, carbon sequestration

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
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.

scholarly journals Assessment of land-use change on streamflow using GIS, remote sensing and a physically-based model, SWAT

2014 ◽  
Vol 364 ◽  
pp. 38-43 ◽  
Author(s):  
J. Y. G. Dos Santos ◽  
R. M. Da Silva ◽  
J. G. Carvalho Neto ◽  
S. M. G. L. Montenegro ◽  
C. A. G. Santos ◽  
...  
Keyword(s):  
Land Use ◽  
Assessment Tool ◽  
Swat Model ◽  
Land Use Changes ◽  
Northeastern Brazil ◽  
Monthly Basis ◽  
Model Response ◽  
Compensation Factor ◽  
Physically Based ◽  
The Impact

Abstract. This study aims to assess the impact of the land-use changes between the periods 1967−1974 and 1997−2008 on the streamflow of Tapacurá catchment (northeastern Brazil) using the Soil and Water Assessment Tool (SWAT) model. The results show that the most sensitive parameters were the baseflow, Manning factor, time of concentration and soil evaporation compensation factor, which affect the catchment hydrology. The model calibration and validation were performed on a monthly basis, and the streamflow simulation showed a good level of accuracy for both periods. The obtained R2 and Nash-Sutcliffe Efficiency values for each period were respectively 0.82 and 0.81 for 1967−1974, and 0.93 and 0.92 for the period 1997−2008. The evaluation of the SWAT model response to the land cover has shown that the mean monthly flow, during the rainy seasons for 1967−1974, decreased when compared to 1997−2008.

scholarly journals SWAT model calibration of a grid-based setup

2012 ◽  
Vol 32 ◽  
pp. 55-61 ◽  
Author(s):  
H. Rathjens ◽  
N. Oppelt
Keyword(s):  
Ground Water ◽  
Catchment Area ◽  
Management Practices ◽  
Spatial Information ◽  
Assessment Tool ◽  
Swat Model ◽  
Computation Time ◽  
Model Parameters ◽  
River Elbe ◽  
Grid Based

Abstract. The eco-hydrological model SWAT (Soil and Water Assessment Tool) is a useful tool to simulate the effects of catchment processes and water management practices on the water cycle. For each catchment some model parameters (e.g. ground water delay time, ground water level) remain constant and therefore are used as constant values; other parameters such as soil types or land use are spatially variable and thus have to be spatially discretized. SWAT setup interfaces process input data to fit the data format requirements and to discretize the spatial characteristics of the catchment area. The primarily used configuration is the sub-watershed discretization scheme. This spatial setup method, however, results in a loss of spatial information which can be problematic for SWAT applications that require a spatially detailed description of the catchment area. At present no SWAT interface is available which provides the management of input and output data based on grid cells. To fill this gap, the authors developed a grid-based model interface. To perform hydrological studies, the SWAT user first calibrates the model to fit to the environmental and hydrological conditions of the catchment. Compared to the sub-watershed approach, the grid-based setup significantly increases model computation time and hence aggravates calibration according to established calibration guidelines. This paper describes how a conventional set of sub-watershed SWAT parameters can be used to calibrate the corresponding grid-based model. The procedure was evaluated in a sub-catchment of the River Elbe (Northern Germany). The simulation of daily discharge resulted in Nash-Sutcliffe efficiencies ranging from 0.76 to 0.78 and from 0.61 to 0.65 for the calibration and validation period respectively; thus model performance is satisfactory. The sub-watershed and grid configuration simulate comparable discharges at the catchment outlet (R2 = 0.99). Nevertheless, the major advantage of the grid-based set-up is an enhanced spatial description of landscape units inducing a more realistic spatial distribution of model output parameters.

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