The importance of parameterization when simulating the hydrologic response of vegetative land-use change

Abstract. Computer models of hydrologic systems are frequently used to investigate the hydrologic response of land-use change. If the modeling results are used to inform resource-management decisions, then providing robust estimates of uncertainty in the simulated response is an important consideration. Here we examine the importance of parameterization, a necessarily subjective process, on uncertainty estimates of the simulated hydrologic response of land-use change. Specifically, we apply the soil water assessment tool (SWAT) model to a 1.4 km2 watershed in south Texas to investigate the simulated hydrologic response of brush management (the mechanical removal of woody plants), a discrete land-use change. The watershed was previously instrumented before and after brush-management activities were undertaken and estimates of precipitation, streamflow, and evapotranspiration (ET) are available; these data were used to condition and verify the model. The role of parameterization in brush-management simulation was evaluated by constructing two models, one with 12 adjustable parameters (reduced parameterization) and one with 1,305 adjustable parameters (full parameterization). Both models were subjected to global sensitivity analysis, Monte Carlo and generalized likelihood uncertainty estimation (GLUE) conditioning to identify important model inputs and to estimate uncertainty in several quantities of interest related to brush management. Many realizations from both parameterizations were identified as behavorial in that they reproduce daily streamflow acceptably well according to Nash-Sutcliffe, percent bias and coefficient of determination. However, the total volumetric ET difference resulting from simulated brush management remains highly uncertain after conditioning to daily streamflow, indicating that streamflow data alone are not sufficient to inform the model inputs that most influence the simulated outcomes of brush management. Additionally, the reduced-parameterization model grossly underestimates uncertainty in the total volumetric ET difference compared to the full-parameterization model; total volumetric ET difference is a primary metric for evaluating the outcomes of brush management. The failure of the reduced-parameterization model to provide robust uncertainty estimates demonstrates the importance of parameterization when attempting to quantify uncertainty in land-use change simulations.

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The importance of parameterization when simulating the hydrologic response of vegetative land-cover change

Hydrology and Earth System Sciences ◽

10.5194/hess-21-3975-2017 ◽

2017 ◽

Vol 21 (8) ◽

pp. 3975-3989 ◽

Cited By ~ 5

Author(s):

Jeremy White ◽

Victoria Stengel ◽

Samuel Rendon ◽

John Banta

Keyword(s):

Land Cover ◽

Land Cover Change ◽

Swat Model ◽

Coefficient Of Determination ◽

Efficiency Coefficient ◽

Hydrologic Response ◽

Mechanical Removal ◽

Uncertainty Estimates ◽

Brush Management ◽

Parameterization Model

Abstract. Computer models of hydrologic systems are frequently used to investigate the hydrologic response of land-cover change. If the modeling results are used to inform resource-management decisions, then providing robust estimates of uncertainty in the simulated response is an important consideration. Here we examine the importance of parameterization, a necessarily subjective process, on uncertainty estimates of the simulated hydrologic response of land-cover change. Specifically, we applied the soil water assessment tool (SWAT) model to a 1.4 km2 watershed in southern Texas to investigate the simulated hydrologic response of brush management (the mechanical removal of woody plants), a discrete land-cover change. The watershed was instrumented before and after brush-management activities were undertaken, and estimates of precipitation, streamflow, and evapotranspiration (ET) are available; these data were used to condition and verify the model. The role of parameterization in brush-management simulation was evaluated by constructing two models, one with 12 adjustable parameters (reduced parameterization) and one with 1305 adjustable parameters (full parameterization). Both models were subjected to global sensitivity analysis as well as Monte Carlo and generalized likelihood uncertainty estimation (GLUE) conditioning to identify important model inputs and to estimate uncertainty in several quantities of interest related to brush management. Many realizations from both parameterizations were identified as behavioral in that they reproduce daily mean streamflow acceptably well according to Nash–Sutcliffe model efficiency coefficient, percent bias, and coefficient of determination. However, the total volumetric ET difference resulting from simulated brush management remains highly uncertain after conditioning to daily mean streamflow, indicating that streamflow data alone are not sufficient to inform the model inputs that influence the simulated outcomes of brush management the most. Additionally, the reduced-parameterization model grossly underestimates uncertainty in the total volumetric ET difference compared to the full-parameterization model; total volumetric ET difference is a primary metric for evaluating the outcomes of brush management. The failure of the reduced-parameterization model to provide robust uncertainty estimates demonstrates the importance of parameterization when attempting to quantify uncertainty in land-cover change simulations.

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Evaluation of integrated impacts of climate and land use change on the river flow regime in Wamkurumadzi River, Shire Basin in Malawi

Journal of Water and Climate Change ◽

10.2166/wcc.2020.138 ◽

2020 ◽

Author(s):

Lusungu Nkhoma ◽

Cosmo Ngongondo ◽

Zuze Dulanya ◽

Maurice Monjerezi

Keyword(s):

Land Use ◽

Land Use Change ◽

Flow Regime ◽

River Discharge ◽

River Flow ◽

Assessment Tool ◽

Swat Model ◽

Temporal Trends ◽

Coefficient Of Determination ◽

Historical Period

Abstract Climate and land use change (CC and LUC hereafter) are interlinked factors that can lead to river flow regime changes, as well as affecting hydrological extremes such as floods and drought. There is now considerable evidence of CC and LUC in many catchments in Malawi but without corresponding evaluations of their impacts on river flow regimes. Therefore, this study assessed how both factors affect the flow regime of Wamkurumadzi River, a key tributary of the major Shire River in southern Malawi. Land use and hydroclimatic data for the basin were first analyzed for spatial–temporal trends in the historical period between the years 1984 and 2015. The Soil and Water Assessment Tool (SWAT) model was then applied with different LUC and CC scenarios in order to assess their sole and combined impacts on the river flow regime. The model was calibrated and validated using the split sample method from the year 1984 to 1999 and from the year 2000 to 2015. Model performance was acceptable according to the selected evaluation criteria, with the Nash–Sutcliffe (NSE) coefficient of 0.78 and coefficient of determination (R2) of 0.96 during calibration and NSE of 0.93 and R2 of 0.98 during validation. Results of the integrated impacts of LUC and CC suggest a slight increase in river discharge of 0.05 m3/s for the period between the 1980s and 2000s. During the 1980s–1990s, both CC through rainfall decreased and LUC resulted in decreases in the mean river discharges by 1.58 and 0.37 m3/s, respectively. The study also found that CC through increased rainfall in the 1990s–2000s decades saw an overall increase of 1.39 m3/s in mean river discharge, while LUC shows the increase of mean river discharge by 0.25 m3/s. However, the study observed that reforestation efforts in the basin were greatly responsible for the alteration of the river flow regime in the later period.

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Comparative Analysis of Bioenergy Crop Impacts on Water Quality Using Static and Dynamic Land Use Change Modeling Approach

Water ◽

10.3390/w12020410 ◽

2020 ◽

Vol 12 (2) ◽

pp. 410 ◽

Cited By ~ 1

Author(s):

Eeshan Kumar ◽

Dharmendra Saraswat ◽

Gurdeep Singh

Keyword(s):

Water Quality ◽

Land Use ◽

Land Use Change ◽

Assessment Tool ◽

Swat Model ◽

State Agency ◽

Bioenergy Crops ◽

Marginal Land ◽

Cache River ◽

Land Area

Researchers and federal and state agency officials have long been interested in evaluating location-specific impact of bioenergy energy crops on water quality for developing policy interventions. This modeling study examines long-term impact of giant miscanthus and switchgrass on water quality in the Cache River Watershed (CRW) in Arkansas, United States. The bioenergy crops were simulated on marginal lands using two variants of a Soil and Watershed Assessment Tool (SWAT) model. The first SWAT variant was developed using a static (single) land-use layer (regular-SWAT) and for the second, a dynamic land-use change feature was used with multiple land use layers (location-SWAT). Results indicated that the regular-SWAT predicted larger losses for sediment, total phosphorus and total nitrogen when compared to location-SWAT at the watershed outlet. The lower predicted losses from location-SWAT were attributed to its ability to vary marginal land area between 3% and 11% during the 20-year modeling period as opposed to the regular-SWAT that used a fixed percentage of marginal land area (8%) throughout the same period. Overall, this study demonstrates that environmental impacts of bioenergy crops were better assessed using the dynamic land-use representation approach, which would eliminate any unintended prediction bias in the model due to the use of a single land use layer.

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The Impacts of Different Land Use Patterns on Water Volume in the Xixian Watershed, China

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.737.728 ◽

2015 ◽

Vol 737 ◽

pp. 728-731 ◽

Cited By ~ 1

Author(s):

Yuan Yuan Han ◽

Tao Cai

Keyword(s):

Land Use ◽

Time Series ◽

Land Use Change ◽

River Basin ◽

Water Conservation ◽

Swat Model ◽

Water Volume ◽

Huaihe River Basin ◽

Huaihe River ◽

Soil And Water

In this study, Soil and Water Assessment Tool (SWAT) model was used to simulate land-use change effects on water quantity in the upper Huaihe river basin above the Xixian hydrological controlling station with a catchment area of 10,190 km2 by the use of three-phase (1980s、1990s、2000s) land-use maps, soil type map (1:200000), 1980 to 2008 daily time series of rainfall from the upper Huaihe river basin. On the basis of the simulated time series of daily runoff, land-use change effects on spatio-temporal change patterns of runoff coefficients and runoff modules were investigated. The results revealed that under the same condition of soil texture and terrain slope the advantage for runoff generation and the sensitivity of rainfall-runoff relationship to rainfall descended by farmland, paddy field, woodland.The outputs could provide important references for soil and water conservation and river health protection in the upper stream of Huaihe river.

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Hydrologic response to future land use change in the Upper Mississippi River Basin by the end of 21st century

Hydrological Processes ◽

10.1002/hyp.11282 ◽

2017 ◽

Vol 31 (21) ◽

pp. 3645-3661 ◽

Cited By ~ 17

Author(s):

Adnan Rajib ◽

Venkatesh Merwade

Keyword(s):

Land Use ◽

Land Use Change ◽

River Basin ◽

21St Century ◽

Mississippi River ◽

Mississippi River Basin ◽

Hydrologic Response ◽

Upper Mississippi River ◽

Upper Mississippi River Basin

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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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Dynamic Land Use Change Prediction and Analysis of Its Impacts on Streamflow for Dabus Watershed, Upper Blue Nile Basin

10.20944/preprints202104.0393.v1 ◽

2021 ◽

Author(s):

Neseredin Bashawal Mangel ◽

Fitsum Berhe

Keyword(s):

Land Use ◽

Land Use Change ◽

Swat Model ◽

Model Performance ◽

Test Analysis ◽

Blue Nile Basin ◽

The Future ◽

Kappa Value ◽

Change Prediction ◽

Basin System

Based on the recorded watershed characteristics, the future conditions on the basin system can be predicted using a different method. In this study, dynamic land-use change and its impacts on the streamflow for the Dabus watershed were predicted using ANN-CA based method. The model performance for accurate prediction of the future land-use change on the Dabus River watershed has been checked by validation of the simulated value with the actual value, hence the overall kappa value (k) = 0.83 for the simulated 2016-LULC validated with actual 2016-LULC. Then, 2026-LULC was predicted based on the 2004 and 2009-LULC. The streamflow for the case of 2004 and 2009-LULC has been simulated using the SWAT model. The value of NSE = 0.87 and 0.90 was attained during validation of simulated streamflow for 2004 and 2009-LULC data cases, respectively. The agreement of simulated value of streamflow with the observed data is indicated as R2 = 0.91 and 0.96 for 2004-LULC and 2009-LULC. The effects of the dynamic land-use change on streamflow for the predicted land use(2026-LULC) catchment were evaluated by T-test analysis. Hence, T-stat =0.04 and -0.002 in the case of simulated streamflow used 2004-LULC and 2009-LULC, respectively compared with simulated value using 2026-LULC.

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Hydrologic modeling of a Himalayan mountain basin by using the SWAT mode

10.5194/hess-2017-100 ◽

2017 ◽

Cited By ~ 3

Author(s):

Sharad K. Jain ◽

Sanjay K. Jain ◽

Neha Jain ◽

Chong-Yu Xu

Keyword(s):

Assessment Tool ◽

Swat Model ◽

Large Population ◽

Water Yield ◽

Model Parameters ◽

Hydrologic Response ◽

Water Balance Components ◽

Daily Streamflow ◽

Hydropower Potential ◽

Himalayan Mountain

Abstract. A large population depends on runoff from Himalayan rivers which have high hydropower potential; floods in these rivers are also frequent. Current understanding of hydrologic response mechanism of these rivers and impact of climate change is inadequate due to limited studies. This paper presents results of modeling to understand the hydrologic response and compute the water balance components of a Himalayan river basin in India viz. Ganga up to Devprayag. Soil and Water Assessment Tool (SWAT) model was applied for simulation of the snow/rainfed catchment. SWAT was calibrated with daily streamflow data for 1992–98 and validated with data for 1999–2005. Manual calibration was carried out to determine model parameters and quantify uncertainty. Results indicate good simulation of streamflow; main contribution to water yield is from lateral and ground water flow. Water yield and ET for the catchments varies between 43–46 % and 57–58 % of precipitation, respectively. The contribution of snowmelt to lateral runoff for Ganga River ranged between 13–20 %. More attention is needed to strengthen spatial and temporal hydrometeorological database for the study basins for improved modeling.

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