Revisiting SWAT as a Saturation-Excess Runoff Model

The Soil Water Assessment Tool (SWAT) is employed throughout the world to simulate watershed processes. A limitation of this model is that locations of saturation excess overland flow in hilly and mountainous regions with an impermeable layer at shallow depth cannot be simulated realistically. The objective of this research is to overcome this limitation with minor changes in the original SWAT code. The new approach is called SWAT-with-impervious-layers (SWAT-wil). Adaptations consisted of redefining the hillslope length, restricting downward percolation from the root zone, and redefining hydrologic response units (HRUs) such that they are associated with the landscape position. Finally, input parameters were chosen such that overland flow from variable saturated areas (VSAs) corresponds to the variable source interpretation of the Soil Conservation Service (SCS) curve number runoff equation. We tested the model for the Town Brook watershed in the Catskill Mountains. The results showed that the discharge calculated with SWAT-wil agreed with observed outflow and results simulated with the original SWAT and SWAT-hillslope (SWAT-HS) models that had a surface aquifer that transferred water between groups of HRUs. The locations of the periodically saturated runoff areas were predicted by SWAT-wil at the right locations. Current users can utilize the SWAT-wil approach for catchments where VSA hydrology predominates.

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Hydrology modelling in Taleghan mountainous watershed using SWAT

Journal of Water and Land Development ◽

10.2478/jwld-2014-0003 ◽

2014 ◽

Vol 20 (1) ◽

pp. 11-18 ◽

Cited By ~ 13

Author(s):

Hamzeh Noor ◽

Mahdi Vafakhah ◽

Masoud Taheriyoun ◽

Mahnoosh Moghadasi

Keyword(s):

Water Resource Management ◽

Assessment Tool ◽

Model Performance ◽

Curve Number ◽

Coefficient Of Determination ◽

Snow Hydrology ◽

Mountainous Regions ◽

Daily Streamflow ◽

Mountainous Watershed ◽

Mountainous Watersheds

Abstract Mountainous regions in Iran are important sources of surface water supply and groundwater recharge. Therefore, accurate simulation of hydrologic processes in mountains at large scales is important for water resource management and for watershed management planning. Snow hydrology is the more important hydrologic process in mountainous watersheds. Therefore, streamflow simulation in mountainous watersheds is often challenging because of irregular topography and complex hydrological processes. In this study, the Soil and Water Assessment Tool (SWAT) was used to model daily runoff in the Taleghan mountainous watershed (800.5 km2) in west of Tehran, Iran. Most of the precipitation in the study area takes place as snow, therefore, modeling daily streamflow in this river is very complex and with large uncertainty. Model calibration was performed with Particle Swarm Optimization. The main input data for simulation of SWAT including Digital Elevation Model (DEM), land use, soil type and soil properties, and hydro-climatological data, were appropriately collected. Model performance was evaluated both visually and statistically where a good relation between observed and simulated discharge was found. The results showed that the coefficient of determination R2 and the Nash- Sutcliffe coefficient NS values were 0.80 and 0.78, respectively. The calibrated model was most sensitive to snowmelt parameters and CN2 (Curve Number). Results indicated that SWAT can provide reasonable predictions daily streamflow from Taleghan watersheds.

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Managing Landscape Irrigation to Avoid Soil and Nutrient Losses

EDIS ◽

10.32473/edis-ss586-2013 ◽

2013 ◽

Vol 2013 (11) ◽

Author(s):

George Hochmuth ◽

Laurie Trenholm ◽

Don Rainey ◽

Esen Momol ◽

Claire Lewis ◽

...

Keyword(s):

Natural Environment ◽

Management Practices ◽

Root Zone ◽

Irrigation Management ◽

Critical Factor ◽

Nutrient Losses ◽

County Agents ◽

The Right ◽

Soil And Water

Proper irrigation management is critical to conserve and protect water resources and to properly manage nutrients in the home landscape. How lawns and landscapes are irrigated directly impacts the natural environment, so landscape maintenance professionals and homeowners must adopt environmentally-friendly approaches to irrigation management. After selecting the right plant for the right place, water is the next critical factor to establish and maintain a healthy lawn and landscape. Fertilization is another important component of lawn and landscape maintenance, and irrigation must be applied correctly, especially following fertilization, to minimize potential nutrient losses. This publication supplements other UF/IFAS Extension publications that also include information on the role of soil and the root zone in irrigation management. This publication is designed to help UF/IFAS Extension county agents prepare materials to directly address nutrient losses from lawns and landscapes caused by inadequate irrigation management practices. This 6-page fact sheet was written by George Hochmuth, Laurie Trenholm, Don Rainey, Esen Momol, Claire Lewis, and Brian Niemann, and published by the UF Department of Soil and Water Science, October 2013. http://edis.ifas.ufl.edu/ss586

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Comparison of performance of tile drainage routines in SWAT 2009 and 2012 in an extensively tile-drained watershed in the Midwest

Hydrology and Earth System Sciences ◽

10.5194/hess-22-89-2018 ◽

2018 ◽

Vol 22 (1) ◽

pp. 89-110 ◽

Cited By ~ 22

Author(s):

Tian Guo ◽

Margaret Gitau ◽

Venkatesh Merwade ◽

Jeffrey Arnold ◽

Raghavan Srinivasan ◽

...

Keyword(s):

Calculation Method ◽

Assessment Tool ◽

Curve Number ◽

Surface Flow ◽

Tile Drainage ◽

Random Pattern ◽

Field Site ◽

Nitrate N ◽

Simulated Surface ◽

Tile Flow

Abstract. Subsurface tile drainage systems are widely used in agricultural watersheds in the Midwestern US and enable the Midwest area to become highly productive agricultural lands, but can also create environmental problems, for example nitrate-N contamination associated with drainage waters. The Soil and Water Assessment Tool (SWAT) has been used to model watersheds with tile drainage. SWAT2012 revisions 615 and 645 provide new tile drainage routines. However, few studies have used these revisions to study tile drainage impacts at both field and watershed scales. Moreover, SWAT2012 revision 645 improved the soil moisture based curve number calculation method, which has not been fully tested. This study used long-term (1991–2003) field site and river station data from the Little Vermilion River (LVR) watershed to evaluate performance of tile drainage routines in SWAT2009 revision 528 (the old routine) and SWAT2012 revisions 615 and 645 (the new routine). Both the old and new routines provided reasonable but unsatisfactory (NSE  <  0.5) uncalibrated flow and nitrate loss results for a mildly sloped watershed with low runoff. The calibrated monthly tile flow, surface flow, nitrate-N in tile and surface flow, sediment and annual corn and soybean yield results from SWAT with the old and new tile drainage routines were compared with observed values. Generally, the new routine provided acceptable simulated tile flow (NSE  =  0.48–0.65) and nitrate in tile flow (NSE  =  0.48–0.68) for field sites with random pattern tile and constant tile spacing, while the old routine simulated tile flow and nitrate in tile flow results for the field site with constant tile spacing were unacceptable (NSE  =  0.00–0.32 and −0.29–0.06, respectively). The new modified curve number calculation method in revision 645 (NSE  =  0.50–0.81) better simulated surface runoff than revision 615 (NSE  =  −0.11–0.49). The calibration provided reasonable parameter sets for the old and new routines in the LVR watershed, and the validation results showed that the new routine has the potential to accurately simulate hydrologic processes in mildly sloped watersheds.

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Comparison of performance of tile drainage routines in SWAT 2009 and 2012 in an extensively tile-drained watershed in the Midwest

10.5194/hess-2017-52 ◽

2017 ◽

Author(s):

Tian Guo ◽

Margaret Gitau ◽

Venkatesh Merwade ◽

Jeffrey Arnold ◽

Raghavan Srinivasan ◽

...

Keyword(s):

Calculation Method ◽

Assessment Tool ◽

Curve Number ◽

Surface Flow ◽

Tile Drainage ◽

Random Pattern ◽

Field Site ◽

Drainage Systems ◽

Nitrate N ◽

Tile Flow

Abstract. Subsurface tile drainage systems are widely used in agricultural watersheds in the Midwestern U.S. Tile drainage systems enable the Midwest area to become highly productive agricultural lands, but can also create environmental problems, for example nitrate-N contamination associated with drainage waters. The Soil and Water Assessment Tool (SWAT) has been used to model watersheds with tile drainage. SWAT2012 revisions 615 and 645 provide new tile drainage routines. However, few studies have used these revisions to study tile drainage impacts at both field and watershed scales. Moreover, SWAT2012 revision 645 improved the soil moisture based curve number calculation method, which has not been fully tested. This study used long-term (1991–2003) field site and river station data from the Little Vermilion River (LVR) watershed to evaluate performance of tile drainage routines in SWAT2009 revision 528 (the old routine) and SWAT2012 revisions 615 and 645 (the new routine). Both routines provided reasonable but unsatisfactory uncalibrated flow and nitrate loss results. Calibrated monthly tile flow, surface flow, nitrate-N in tile and surface flow, sediment and annual corn and soybean yield results from SWAT with the old and new tile drainage routines were compared with observed values. Generally, the new routine provided acceptable simulated tile flow (NSE = 0.50–0.68) and nitrate in tile flow (NSE = 0.50–0.77) for both field sites with random pattern tile and constant tile spacing, while the old routine simulated tile flow and nitrate in tile flow results for the field site with constant tile spacing were unacceptable (NSE = −0.77– −0.20 and −0.99–0.21 respectively). The new modified curve number calculation method in revision 645 (NSE = 0.56–0.82) better simulated surface runoff than revision 615 (NSE = −5.95 ~ 0.5). Calibration provided reasonable parameter sets for the old and new routines in LVR watershed, and the validation results showed that the new routine has the potential to accurately simulate hydrologic processes in mildly-sloped watersheds.

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Picking the Right Tool for the Job: A Reliability Study of 4 Assessment Tools for Central Venous Catheter Insertion

Journal of Graduate Medical Education ◽

10.4300/jgme-d-19-00107.1 ◽

2019 ◽

Vol 11 (4) ◽

pp. 422-429

Author(s):

Jason A. Lord ◽

Danny J. Zuege ◽

Maria Palacios Mackay ◽

Amanda Roze des Ordons ◽

Jocelyn Lockyer

Keyword(s):

Intensive Care ◽

Central Venous Catheter ◽

Rating Scales ◽

Assessment Tool ◽

Generalizability Theory ◽

Venous Catheter ◽

Assessment Tools ◽

Global Rating ◽

Central Venous ◽

The Right

ABSTRACT Background Determining procedural competence requires psychometrically sound assessment tools. A variety of instruments are available to determine procedural performance for central venous catheter (CVC) insertion, but it is not clear which ones should be used in the context of competency-based medical education. Objective We compared several commonly used instruments to determine which should be preferentially used to assess competence in CVC insertion. Methods Junior residents completing their first intensive care unit rotation between July 31, 2006, and March 9, 2007, were video-recorded performing CVC insertion on task trainer mannequins. Between June 1, 2016, and September 30, 2016, 3 experienced raters judged procedural competence on the historical video recordings of resident performance using 4 separate tools, including an itemized checklist, Objective Structured Assessment of Technical Skills (OSATS), a critical error assessment tool, and the Ottawa Surgical Competency Operating Room Evaluation (O-SCORE). Generalizability theory (G-theory) was used to compare the performance characteristics among the tools. A decision study predicted the optimal testing environment using the tools. Results At the time of the original recording, 127 residents rotated through intensive care units at the University of Calgary, Alberta, Canada. Seventy-seven of them (61%) met inclusion criteria, and 55 of those residents (71%) agreed to participate. Results from the generalizability study (G-study) demonstrated that scores from O-SCORE and OSATS were the most dependable. Dependability could be maintained for O-SCORE and OSATS with 2 raters. Conclusions Our results suggest that global rating scales, such as the OSATS or the O-SCORE tools, should be preferentially utilized for assessment of competence in CVC insertion.

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Improved Curve Number Estimation in SWAT by Reflecting the Effect of Rainfall Intensity on Runoff Generation

Water ◽

10.3390/w11010163 ◽

2019 ◽

Vol 11 (1) ◽

pp. 163 ◽

Cited By ~ 7

Author(s):

Dejian Zhang ◽

Qiaoyin Lin ◽

Xingwei Chen ◽

Tian Chai

Keyword(s):

Rainfall Intensity ◽

Assessment Tool ◽

Flow Simulation ◽

Daily Rainfall ◽

Curve Number ◽

Base Flow ◽

Data Sets ◽

Rainfall Runoff ◽

Runoff Generation ◽

The Relationship

Determining the amount of rainfall that will eventually become runoff and its pathway is a crucial process in hydrological modelling. We proposed a method to better estimate curve number by adding an additional component (AC) to better account for the effects of daily rainfall intensity on rainfall-runoff generation. This AC is determined by a regression equation developed from the relationship between the AC series derived from fine-tuned calibration processes and observed rainfall series. When incorporated into the Soil and Water Assessment Tool and tested in the Anxi Watershed, it is found, overall, the modified SWAT (SWAT-ICN) outperformed the original SWAT (SWAT-CN) in terms of stream flow, base flow, and annual extreme flow simulation. These models were further evaluated with the data sets of two adjacent watersheds. Similar results were achieved, indicating the ability of the proposed method to better estimate curve number.

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Performance of HEC-HMS and SWAT to simulate streamflow in the sub-humid tropical Hemavathi catchment

Journal of Water and Climate Change ◽

10.2166/wcc.2021.072 ◽

2021 ◽

Author(s):

N. C. Sanjay Shekar ◽

D. C. Vinay

Keyword(s):

Model Calibration ◽

Assessment Tool ◽

Swat Model ◽

Model Performance ◽

Curve Number ◽

Coefficient Of Determination ◽

Hydrological Models ◽

Daily Streamflow ◽

Compensation Factor ◽

Elevation Model

Abstract The present study was conducted to examine the accuracy and applicability of the hydrological models Soil and Water Assessment Tool (SWAT) and Hydrologic Engineering Center (HEC)- Hydrologic Modeling System (HMS) to simulate streamflows. Models combined with the ArcGIS interface have been used for hydrological study in the humid tropical Hemavathi catchment (5,427 square kilometer). The critical focus of the streamflow analysis was to determine the efficiency of the models when the models were calibrated and optimized using observed flows in the simulation of streamflows. Daily weather gauge stations data were used as inputs for the models from 2014–2020 period. Other data inputs required to run the models included land use/land cover (LU/LC) classes resulting from remote sensing satellite imagery, soil map and digital elevation model (DEM). For evaluating the model performance and calibration, daily stream discharge from the catchment outlet data were used. For the SWAT model calibration, available water holding capacity by soil (SOL_AWC), curve number (CN) and soil evaporation compensation factor (ESCO) are identified as the sensitive parameters. Initial abstraction (Ia) and lag time (Tlag) are the significant parameters identified for the HEC-HMS model calibration. The models were subsequently adjusted by autocalibration for 2014–2017 to minimize the variations in simulated and observed streamflow values at the catchment outlet (Akkihebbal). The hydrological models were validated for the 2018–2020 period by using the calibrated models. For evaluating the simulating daily streamflows during calibration and validation phases, performances of the models were conducted by using the Nash-Sutcliffe model efficiency (NSE) and coefficient of determination (R2). The SWAT model yielded high R2 and NSE values of 0.85 and 0.82 for daily streamflow comparisons for the catchment outlet at the validation time, suggesting that the SWAT model showed relatively good results than the HEC-HMS model. Also, under modified LU/LC and ungauged streamflow conditions, the calibrated models can be later used to simulate streamflows for future predictions. Overall, the SWAT model seems to have done well in streamflow analysis capably for hydrological studies.

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Saturation excess overland flow accelerates the spread of a generalist soil-borne pathogen

10.31223/osf.io/j45u6 ◽

2020 ◽

Author(s):

Jean Wilkening ◽

Enrique Cardillo ◽

Enrique Abad ◽

Sally Thompson

Keyword(s):

Overland Flow ◽

Saturation Excess

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Modelling the Event-Based Hydrological Response of Mediterranean Forests to Prescribed Fire and Soil Mulching with Fern Using the Curve Number, Horton and USLE-Family (Universal Soil Loss Equation) Models

Land ◽

10.3390/land10111166 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1166

Author(s):

Bruno Gianmarco Carra ◽

Giuseppe Bombino ◽

Manuel Esteban Lucas-Borja ◽

Pietro Denisi ◽

Pedro Antonio Plaza-Álvarez ◽

...

Keyword(s):

Prescribed Fire ◽

Soil Loss ◽

Overland Flow ◽

Curve Number ◽

Soil Conditions ◽

Mediterranean Forests ◽

Hydrological Response ◽

Infiltration Excess ◽

Runoff And Soil Loss ◽

Scs Cn

The SCS-CN, Horton, and USLE-family models are widely used to predict and control runoff and erosion in forest ecosystems. However, in the literature there is no evidence of their use in Mediterranean forests subjected to prescribed fire and soil mulching. To fill this gap, this study evaluates the prediction capability for runoff and soil loss of the SCS-CN, Horton, MUSLE, and USLE-M models in three forests (pine, chestnut, and oak) in Southern Italy. The investigation was carried out at plot and event scales throughout one year, after a prescribed fire and post-fire soil mulching with fern. The SCS-CN and USLE-M models were accurate in predicting runoff volume and soil loss, respectively. In contrast, poor predictions of the modelled hydrological variables were provided by the models in unburned plots, and by the Horton and MUSLE models for all soil conditions. This inaccuracy may have been due to the fact that the runoff and erosion generation mechanisms were saturation-excess and rainsplash, while the Horton and MUSLE models better simulate infiltration-excess and overland flow processes, respectively. For the SCS-CN and USLE-M models, calibration was needed to obtain accurate predictions of surface runoff and soil loss; furthermore, different CNs and C factors must be input throughout the year to simulate the variability of the hydrological response of soil after fire. After calibration, two sets of CNs and C-factor values were suggested for applications of the SCS-CN and USLE-M models, after prescribed fire and fern mulching in Mediterranean forests. Once validated in a wider range of environmental contexts, these models may support land managers in controlling the hydrology of Mediterranean forests that are prone to wildfire risks.

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Assessing the long-term hydrologic response to wildfires in mountainous regions

10.5194/hess-2017-604 ◽

2017 ◽

Cited By ~ 1

Author(s):

Aaron Havel ◽

Ali Tasdighi ◽

Mazdak Arabi

Keyword(s):

Assessment Tool ◽

Spatial Scales ◽

Swat Model ◽

Hydrologic Response ◽

Mountainous Regions ◽

Total Runoff ◽

Streamflow Statistics ◽

Flow Duration Curves ◽

Hydrologic Responses

Abstract. This study aims to understand the long-term hydrologic responses to wildfires in mountainous regions at various spatial scales. The Soil and Water Assessment Tool (SWAT) was used to evaluate hydrologic response of the upper Cache la Poudre watershed in Colorado to the 2012 High Park and Hewlett wildfire events. A baseline SWAT model was established to simulate the hydrology of the study area between the years 2000 and 2014. The effects of wildfires on land cover were accounted for in the model using the SWAT land use update module. The wildfire effects on curve numbers were determined comparing the probability distribution of curve numbers after calibrating the model for pre and post wildfire conditions. Daily calibration and testing of the model produced very good results. No-wildfire and wildfire scenarios were created and compared to quantify changes in average annual total runoff volume, water budgets, and full streamflow statistics at different spatial scales. At the watershed scale, wildfire conditions showed little impact on the hydrologic responses. However, a runoff increase up to 75 percent was observed between the scenarios in sub-watersheds with high burn intensity. Generally, higher surface runoff and decreased subsurface flow were observed under post-wildfire conditions. Flow-duration curves developed for burned sub-basins using full streamflow statistics showed that less frequent streamflows become greater in magnitude. A strong (R2 > 0.8) and significant (p

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