Comparative study of two watershed scale models to calculate diffuse phosphorus pollution

2006 ◽  
Vol 53 (2) ◽  
pp. 281-288 ◽  
Author(s):  
A. Kovacs
Keyword(s):  
Swat Model ◽  
Inorganic Phosphorus ◽  
Empirical Method ◽  
Scenario Development ◽  
Phosphorus Pollution ◽  
Support Tool ◽  
Scale Models ◽  
Physically Based ◽  
River Loads ◽  
Phosphorus Emission

The aim of this study was to compare and assess models having different principles to calculate diffuse phosphorus emissions on a selected watershed. The empirical MONERIS model and the physically based SWAT model were evaluated for comparative purposes. The approaches were applied for a sub-basin of the Hungarian Zala River watershed for five years. The calculated river loads were checked by the measured values at the catchment outlet. Due to the dissimilar results of water balance and erosion calculations, a highly different phosphorus emission was computed. It was also concluded that in the case of transport-limited watersheds, the SWAT model calculates phosphorus river loads slightly inaccurately, since it does not include the description of fate of inorganic phosphorus interacting with sediment during the channel transport. When these processes are taken into account, modeling results fit better the measured loads. The MONERIS model calculates acceptable river load by assuming very intensive in-stream retention. Additionally, the empirical method can be useful for long-term investigations as a decisions support tool for preliminary design. However, for detailed emission assessment and scenario development the physically based approach seems to be more appropriate.

scholarly journals A New Physically-Based Spatially-Distributed Groundwater Flow Module for SWAT+

Hydrology ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 75
Author(s):  
Ryan T. Bailey ◽  
Katrin Bieger ◽  
Jeffrey G. Arnold ◽  
David D. Bosch
Keyword(s):  
Water Balance ◽  
Groundwater Flow ◽  
Land Surface ◽  
Assessment Tool ◽  
Swat Model ◽  
Watershed Model ◽  
Groundwater Head ◽  
Physically Based ◽  
Spatially Distributed ◽  
Modeling Code

Watershed models are used worldwide to assist with water and nutrient management under conditions of changing climate, land use, and population. Of these models, the Soil and Water Assessment Tool (SWAT) and SWAT+ are the most widely used, although their performance in groundwater-driven watersheds can sometimes be poor due to a simplistic representation of groundwater processes. The purpose of this paper is to introduce a new physically-based spatially-distributed groundwater flow module called gwflow for the SWAT+ watershed model. The module is embedded in the SWAT+ modeling code and is intended to replace the current SWAT+ aquifer module. The model accounts for recharge from SWAT+ Hydrologic Response Units (HRUs), lateral flow within the aquifer, Evapotranspiration (ET) from shallow groundwater, groundwater pumping, groundwater–surface water interactions through the streambed, and saturation excess flow. Groundwater head and groundwater storage are solved throughout the watershed domain using a water balance equation for each grid cell. The modified SWAT+ modeling code is applied to the Little River Experimental Watershed (LREW) (327 km2) in southern Georgia, USA for demonstration purposes. Using the gwflow module for the LREW increased run-time by 20% compared to the original SWAT+ modeling code. Results from an uncalibrated model are compared against streamflow discharge and groundwater head time series. Although further calibration is required if the LREW model is to be used for scenario analysis, results highlight the capabilities of the new SWAT+ code to simulate both land surface and subsurface hydrological processes and represent the watershed-wide water balance. Using the modified SWAT+ model can provide physically realistic groundwater flow gradients, fluxes, and interactions with streams for modeling studies that assess water supply and conservation practices. This paper also serves as a tutorial on modeling groundwater flow for general watershed modelers.

Chemical-Mechanical Planarization of Low-k Polymers for Advanced IC Structures

2002 ◽  
Vol 124 (4) ◽  
pp. 362-366 ◽  
Author(s):  
Christopher L. Borst ◽  
Dipto G. Thakurta ◽  
William N. Gill ◽  
Ronald J. Gutmann
Keyword(s):  
Dielectric Constant ◽  
Surface Chemistry ◽  
Chemical Mechanical Planarization ◽  
Low Dielectric Constant ◽  
Chemical Company ◽  
Low Dielectric ◽  
Scale Models ◽  
Physically Based ◽  
Thickness Measurements ◽  
Low K

Successful integration of copper and low dielectric constant (low-k) materials is dependent on robust chemical-mechanical planarization (CMP) during damascene patterning. This process includes the direct removal of copper and interaction of the copper slurry with the underlying dielectric. Experiments were designed and performed to examine the CMP of two low-k polymers from Dow Chemical Company, bis-benzocyclobutene (BCB*, k=2.65) and “silicon-application low-k material” (SiLK* resin, k=2.65) with both acidic slurries suitable for copper damascene patterning and a KH phthalate-based model slurry developed for SiLK. Blanket polymer films were polished in order to determine the interactions that occur when copper and liner materials are removed by the damascene CMP process. Removal rates were obtained from material thickness measurements, post-CMP surface topography from AFM scans, and post-CMP surface chemistry from XPS measurements. Physically based wafer-scale models are presented which are compatible with the experimental results.

scholarly journals Spatio-temporal analysis of sediment yield with a physically based model for a data-scarce headwater in Konya Closed Basin, Turkey

2021 ◽  
Author(s):  
Cihangir Koycegiz ◽  
Meral Buyukyildiz ◽  
Serife Yurdagul Kumcu
Keyword(s):  
Sediment Yield ◽  
Assessment Tool ◽  
Swat Model ◽  
Temporal Analysis ◽  
Mathematical Methods ◽  
Closed Basin ◽  
Physically Based ◽  
Spatio Temporal ◽  
Sediment Data ◽  
Semi Empirical

Abstract There are many empirical, semi-empirical and mathematical methods that have been developed to estimate sediment yield by researchers. In the last decades, the advancement in computer technologies has increased the use of mathematical models as they can solve the system more rapidly and accurately. The Soil and Water Assessment Tool (SWAT) is one of the physically based hydrological models that is preferred to compute sediment yield. In this study, spatial and temporal analysis of sediment yield in the Çarşamba Stream located at the Konya Closed Basin has been investigated using the SWAT model. Streamflow and sediment data collected during the 2003–2015 time period have been used in the analysis. Consequently, the SWAT presented satisfactory results compared with R2 = 0.68, Nash–Sutcliffe Efficiency (NSE) = 0.68 in calibration and R2 = 0.76, NSE = 0.66 in validation. According to the model results, spatial asymmetry in terms of sediment yield was determined in the sub-basins of the study area.

scholarly journals Modeling the Hydrological Characteristics of Hangar Watershed, Ethiopia

2020 ◽  
Author(s):  
Abdata Galata
Keyword(s):  
Goodness Of Fit ◽  
Assessment Tool ◽  
Swat Model ◽  
Integrated Water Resources Management ◽  
Water Balance Components ◽  
Warm Up ◽  
Hydrological Characteristics ◽  
Digital Elevation ◽  
Physically Based ◽  
Elevation Model

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.

scholarly journals Flow Simulation and Storage Assessment in an Ungauged Irrigation Tank Cascade System Using the SWAT Model

2021 ◽  
Vol 13 (23) ◽  
pp. 13158
Author(s):  
Koppuravuri Ramabrahmam ◽  
Venkata Reddy Keesara ◽  
Raghavan Srinivasan ◽  
Deva Pratap ◽  
Venkataramana Sridhar
Keyword(s):  
State Government ◽  
Arid Regions ◽  
Assessment Tool ◽  
Swat Model ◽  
Flow Simulation ◽  
Hydrological Processes ◽  
Cascade System ◽  
Physically Based ◽  
Irrigation Tank ◽  
Semi Arid

In the semi-arid regions of South Asia, tank systems are the major source of irrigation. In India, the Telangana state government has initiated the Mission Kakatiya program to rejuvenate irrigation tank systems. Understanding the hydrological processes that supply water to these systems is critical to the success of these types of programs in India. The current study attempted to comprehend the hydrological processes and flow routing in the Salivagu watershed tank cascade system in Telangana. There are a lot of ungauged tank cascade systems in this region. Soil Water Assessment Tool (SWAT), a physically-based model, was used to simulate flow patterns in the Salivagu watershed with and without tank systems. The geospatially extracted area and volume were used for this study provided by WBIS-Bhuvan-NRSC. Additionally, the Katakshapur Tank Cascade System (KTCS) was chosen to analyze the water availability in each tank using the water balance approach. The Salivagu watershed flow simulation without tanks overestimated streamflow. The volume difference in flow between with and without tank was 606 Mm3, 615.9 Mm3, and 1011 Mm3 in 2017, 2018, and 2019, respectively. The SWAT simulated volumes of the Ramchandrapur and Dharmaraopalle tanks in KTCS were merely satisfied because the tank size was less than 0.7 km2 and the storage capacity was up to 1 Mm3. Due to tank sizes more than 0.8 km2 and capacities greater than 2 Mm3, the Mallampalli and Katakshapur tank simulation findings were in good agreement with WBIS-Bhuvan-NRSC. This research advances our understanding of the hydrological processes in ungauged cascading tank systems in tropical semi-arid regions.

scholarly journals Analysis of hydrological processes with semi-distributed model

2021 ◽  
Author(s):  
Rahmatullah Sediqi ◽  
Mustafa Tombul
Keyword(s):  
Sensitivity Analysis ◽  
Assessment Tool ◽  
Swat Model ◽  
Hydrological Processes ◽  
Distributed Model ◽  
Model Sensitivity ◽  
Discharge Data ◽  
Calibration And Validation ◽  
Physically Based ◽  
Calibration Program

The Soil and Water Assessment Tool (SWAT), a semi-distributed physically-based hydrological model, is broadly used for simulating streamflow and analyzing hydrological processes in the basin. The SWAT model was applied to analyze the hydrological processes in Göksu Himmetli, Zamanti-Ergenuşağı, Göksun Poskoflu ve Hurman-Gözler Üstü sub-basins in the upper region of Seyhan and Ceyhan watersheds located in the south of Turkey. Model sensitivity analysis, calibration, and validation were performed using SWAT-CUP automatic calibration program and SUFI-2 algorithm. According to the model sensitivity analysis results, the most sensitive parameters in these basins have been seen as CN2, ALPHA_BNK, CH_K2, and GW_DELAY. In this study, 11 years (1994-2004) meteorological and eight years (1997-2004) observed flow data were used, three years for the model warm-up period, five years (1997-2001) for calibration, and three years (2002-2004) for validation. The model statistical performance was evaluated using the Nash Sutcliffe Efficiency (NSE) as the objective function. As the result of the model calibration and validation, the NSE value in the considered four sub-basins varied between 0,70 - 0,90. The results obtained in the study showed a relatively high correlation between the observed and simulated discharge data.

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.

A novel toolkit to streamline Land Use Land Cover change assessment in the SWAT+ model to enhance flood management and infrastructure decisions

2021 ◽  
Author(s):  
Alex Rigby ◽  
Sopan Patil ◽  
Panagiotis Ritsos
Keyword(s):  
Land Use ◽  
Decision Support ◽  
Swat Model ◽  
Decision Support Tool ◽  
Flood Management ◽  
Land Use Land Cover ◽  
End User ◽  
Support Tool ◽  
Lulc Changes ◽  
Hydrological Impacts

<p>Land Use Land Cover (LULC) change is widely recognised as one of the most important factors impacting river basin hydrology.  It is therefore imperative that the hydrological impacts of various LULC changes are considered for effective flood management strategies and future infrastructure decisions within a catchment.  The Soil and Water assessment Tool (SWAT) has been used extensively to assess the hydrological impacts of LULC change.  Areas with assumed homogeneous hydrologic properties, based on their LULC, soil type and slope, make up the basic computational units of SWAT known as the Hydrologic Response Units (HRUs).  LULC changes in a catchment are typically modelled by SWAT through alterations to the input files that define the properties of these HRUs.  However, to our knowledge at least, the process of making such changes to the SWAT input files is often cumbersome and non-intuitive.  This affects the useability of SWAT as a decision support tool amongst a wider pool of applied users (e.g., engineering teams in environmental regulatory agencies and local authorities).  In this study, we seek to address this issue by developing a user-friendly toolkit that will: (1) allow the end user to specify, through a Graphical User Interface (GUI), various types of LULC changes at multiple locations within their study catchment, (2) run the SWAT+ model (the latest version of SWAT) with the specified LULC changes, and (3) enable interactive visualisation of the different SWAT+ output variables to quantify the hydrological impacts of these scenarios.  Importantly, our toolkit does not require the end user to have any operational knowledge of the SWAT+ model to use it as a decision support tool.  Our toolkit will be trialled at 15 catchments in Gwynedd county, Wales, which has experienced multiple occurrences of high flood events, and consequent economic damage, in the recent past.  We anticipate this toolkit to be a valuable addition to the decision-making processes of Gwynedd County Council for the planning and development of future flood alleviation schemes as well as other infrastructure projects.</p>

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