Title |
Study on Improvement of Calibration/Validation of SWAT for Spatio-Temporal Analysis of Land Uses and Rainfall Patterns |
Authors |
이지원 ( Ji Won Lee ) ; 금동혁 ( Dong Hyuk Kum ) ; 김범철 ( Bom Chul Kim ) ; 김영석 ( Young Sug Kim ) ; 정교철 ( Gyo Cheol Jeong ) ; 김기성 ( Ki Sung Kim ) ; 최중대 ( Joong Dae Choi ) ; 임경재 ( Kyoung Jae Lim ) |
Keywords |
Calibration; Mandae; Sediment; Spatio-temporal; SWAT model; Validation |
Abstract |
The purpose of this study was to evaluate effects of spatio-temporal changes in land uses and rainfall magnitude using the Soil and Water Assessment Tool (SWAT). Prior of application of the model to real-world problem, the model should be calibrated and validated properly. In most modeling approaches, the validation process is done assuming no significant changes occurring at the study watershed between calibration and validation periods, which is not proper assumption for agricultural watersheds. If simulated results obtained with calibrated parameters match observed data with higher accuracy for validation period, this does not always mean the simulated result represents rainfall-runoff, pollutant generation and transport mechanism for validation period because temporal and spatial variables and rainfall magnitude are often not the same. In this study SWAT was applied to Mandae study watershed in Korea to evaluate effects of spatio-temporal changes in landuses using 2009 and 2010 crop data for each field at the watershed. The Nash-Sutcliffe model efficiency (NSE) values for calibration and validation with either 2009 or 2010 was evaluated and the NSE value for calibration with 2009 and calibration with 2010 were compared. It was found that if there is substantial change in land use and rainfall, model calibration period should be determined to reflect those changes. Through these approaches, inherent limitation of the SWAT, which does not consider changes in land uses over the simulation period, was investigated. Also, Effects of changes in rainfall magnitude during calibration process were analyzed. |