Two-Way Calibration-Validation of SWAT Model for a Small Prairie Watershed with Short Observed Record

Abstract

The Soil Water Assessment Tool (SWAT) model was calibrated for a small watershed with extensive irrigation, low runoff, and a short (2004)(2005)(2006)(2007) period of record in the semi-arid region of the Canadian prairies. The watershed is located on a segment of a river. The net flow between the upstream (inlet) and downstream (outlet) locations of the reach comprises only a fraction of the streamflow at the outlet. This type of watershed is rarely investigated and generally different from the ''pear shaped'' single outlet watersheds presented in SWAT literature. The objectives of this study were to determine if SWAT could be calibrated and validated on this unique watershed using one-and two-way calibration-validation methods, and to determine the effect of a variable climatic record on calibrated and validated parameters. To study the effect of a variable climatic record on the calibrated parameters for this watershed a two-way calibration verification scheme that involved two scenarios was used. Scenario 1 involved calibration using 2004 (average precipitation) and 2005 (above average precipitation) and validation on 2006 and 2007 (both below average precipitation). For scenario 2, the calibration and validation periods were reversed. A third scenario utilized the period of 2004Á2006 for calibration and reserved the 2007 data for validation. The objective criteria used to evaluate model performance included decomposition of the Root Mean Square Error (RMSE) into systematic and unsystematic error, the Nash-Sutcliffe efficiency coefficient (EF) and the coefficient of determination (R 2 ) as model best fit objective functions. The calibration results were satisfactory for scenarios 1 and 3. The calibration of scenario 2 and the validation results for all three scenarios were unsatisfactory. The objective criteria calculated separately for each year in the calibration records showed the calibration results were satisfactory for 2005 only, which is the only wet year in the observed record with above average precipitation. Thus, calibrated parameters were mainly influenced by the 2005 wet season. Therefore, SWAT model calibration on a mixed record of wet and dry conditions will reflect the hydrological processes dominant during wet conditions rather than those observed during dry ones.

Assessing the Importance of Potholes in the Canadian Prairie Region under Future Climate Change Scenarios

“…For model calibration, key parameters that govern hydrologic processes of the study watershed were selected based on available literature [34,35,57,58,[60][61][62][91][92][93]. A total of 27 parameters were considered in the calibration process.…”

Predicting water quality trends resulting from forest cover change in an agriculturally dominated river basin in Eastern Ontario, Canada

“…Secondly, the calculated loadings of water, sediment, and nutrients from the HRUs are routed through the stream network where SWAT tracks mass flow and estimates chemical transformations in the stream and the streambed (Neitsch et al 2011). The SWAT model has been used successfully for many different Canadian modeling applications (e.g., Liu et al 2007;Rahbeh et al 2011;Frey et al 2013;Golmohammadi et al 2014;Zhang et al 2020).…”

Uso do modelo SWAT para avaliação do impacto de conservação em microbacia nos Andes Equatoriano na geração de serviço ecossistêmico hidrológico.

“…A composição de Areia, Silte e Argila no solo, o fator de erodibilidade (K_USLE), o albedo e a definição de grupo hidrológico foram extraídos de publicações referentes a experimentos de campo em bacias equatorianas localizadas no Páramo (Crespo et al, 2006;Crespo et al, 2011;Garcia, 2018 (Stehr et al, 2010;Rahbeh et al, 2011;Gómez et al, 2013;Omani et al, 2017). São eles:…”

“…Fonte: Stehr et al, 2010;Rahbeh et al, 2011;Gómez et al, 2013;Omani et al, 2017 Parcela O período de 01 de janeiro de 2015 a 31 de outubro de 2016 foi utilizado para calibração e o de 01 de janeiro de 2014 a 31 de dezembro de 2014 foi utilizado para validação, ambos com passo diário. Esses foram os períodos que apresentaram melhores valores para calibração e validação.…”

“…Os parâmetros descritos na Tabela 4 foram calibrados pelo método de calibração automática SUFI-2, e para cada um deles foi proposto um intervalo inicial de valores conforme indicado por publicações em bacias nos Andes equatoriano (Stehr et al, 2010;Rahbeh et al, 2011;Gómez et al, 2013;Omani et al, 2017 Considerando os diferentes resultados encontrados na literatura sobre os impactos no regime hidrológico e nas dinâmicas de vazões médias, máximas e mínimas, é imprescindível que se vá além de generalizações e se considere as características estruturais e ecológicas da cobertura de terra e do local para que se obtenha resultados consistentes que possam guiar as tomadas de decisão em relação a implementação de diferentes usos da terra, conforme os benefícios que se pretende alcançar.…”