TY - JOUR
T1 - Simulating internal watershed processes using multiple SWAT models
AU - Apostel, Anna
AU - Kalcic, Margaret
AU - Dagnew, Awoke
AU - Evenson, Grey
AU - Kast, Jeffrey
AU - King, Kevin
AU - Martin, Jay
AU - Muenich, Rebecca Logsdon
AU - Scavia, Donald
N1 - Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/3/10
Y1 - 2021/3/10
N2 - The need for effective water quality models to help guide management and policy, and extend monitoring information, is at the forefront of recent discussions related to watershed management. These models are often calibrated and validated at the basin outlet, which ensures that models are capable of evaluating basin scale hydrology and water quality. However, there is a need to understand where these models succeed or fail with respect to internal process representation, as these watershed-scale models are used to inform management practices and mitigation strategies upstream. We evaluated an ensemble of models—each calibrated to in-stream observations at the basin outlet—against discharge and nutrient observations at the farm field scale to determine the extent to which these models capture field-scale dynamics. While all models performed well at the watershed outlet, upstream performance varied. Models tended to over-predict discharge through surface runoff and subsurface drainage, while under-predicting phosphorus loading through subsurface drainage and nitrogen loading through surface runoff. Our study suggests that while models may be applied to predict impacts of management at the basin scale, care should be taken in applying the models to evaluate field-scale management and processes in the absence of data that can be incorporated at that scale, even with the use of multiple models.
AB - The need for effective water quality models to help guide management and policy, and extend monitoring information, is at the forefront of recent discussions related to watershed management. These models are often calibrated and validated at the basin outlet, which ensures that models are capable of evaluating basin scale hydrology and water quality. However, there is a need to understand where these models succeed or fail with respect to internal process representation, as these watershed-scale models are used to inform management practices and mitigation strategies upstream. We evaluated an ensemble of models—each calibrated to in-stream observations at the basin outlet—against discharge and nutrient observations at the farm field scale to determine the extent to which these models capture field-scale dynamics. While all models performed well at the watershed outlet, upstream performance varied. Models tended to over-predict discharge through surface runoff and subsurface drainage, while under-predicting phosphorus loading through subsurface drainage and nitrogen loading through surface runoff. Our study suggests that while models may be applied to predict impacts of management at the basin scale, care should be taken in applying the models to evaluate field-scale management and processes in the absence of data that can be incorporated at that scale, even with the use of multiple models.
KW - Calibration/validation
KW - Ensemble modeling
KW - Field scale
KW - Nutrient loading
KW - Soil and Water Assessment Tool (SWAT)
KW - Subsurface drainage
UR - http://www.scopus.com/inward/record.url?scp=85098928761&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85098928761&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2020.143920
DO - 10.1016/j.scitotenv.2020.143920
M3 - Article
C2 - 33339624
AN - SCOPUS:85098928761
SN - 0048-9697
VL - 759
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 143920
ER -