SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Model calibration for flow rate and total phosphorous export simulations in the watersheds of the rivers Conrado and Pinheiro, Pato Branco (PR) 
Authors:Baltokoski, V., M.H.F. Tavares, R.E. Machado and M.P. de Oliveira 
Journal:Revista Brasileira de Ciência do Solo 
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URL (non-DOI journals): 
Broad Application Category:hydrologic & pollutant 
Primary Application Category:calibration, sensitivity, and/or uncertainty analysis 
Secondary Application Category:nutrient cycling and transport 
Watershed Description:24.1 km^2 Conrado River and 28.68 km^2 Pinheiro River, in southern Brazil 
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Validation Summary: 
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Abstract:Hydrological models developed to predict the impacts of non-point source pollution and land use and occupation on water quality have been extremely useful in the study of agricultural systems. For this purpose, the objective of this study was to evaluate the sensitivity of the model SWAT 2005 (Soil and Water Assessment Tool) to simulate the flow rate and total phosphorous flow mass. The research was conducted in two contiguous watersheds of the Conrado and Pinheiro rivers, affluents to the Pato Branco river, in Pato Branco and Mariopolis counties, state of Paraná. Climatological data of the period 1979-2006 and observation data of flow rate and total phosphorous export of the years 2004 and 2005 from two weather stations (in the lower part of the main water course of the Conrado and Pinheiro rivers) were used. The model requires input data in spatial format of land use and soil data, associated to a digital elevation model (DEM). The AvSWAT_X interface was used with ArcView 3.3® and its extension Spatial Analyst 2.0®, for data input and manipulation. Monthly and yearly averages of flow rate and total phosphorous export were compared to the observed values. The Nash-Sutcliffe Coefficient (COE) was used to evaluate the modeling efficiency. The modeling was improved by including the sensitivity analysis, autocalibration tool and manual adjustment, showing that, with regular sampling frequency, the SWAT 2005 model simulated the flow rate and total phosphorous export satisfactorily. In the case of irregular sampling frequency and limited dataset, however, autocalibration and sensitivity analysis were not efficient to simulate the flow rate and total phosphorous export results. Besides, different sensitivity levels were observed for the two stations, reflecting inequalities of the Hydrologic Response Units. The simulated monthly distribution of phosphorous export showed the heterogeneity of P application over the course of the year. 
Keywords:geotechnologies, hydrologic modeling, nonpoint source pollution, water quality, phosphorous transport