HYDROLOGIC EVALUATION OF THE SOIL AND WATER ASSESSMENT TOOL FOR A LARGE TILE-DRAINED WATERSHED IN IOWA

作者：C. H. Green, Mark D. Tomer, M. Di Luzio, Jeffery G. Arnold · 发表于：Transactions of the ASABE · 年份：2006 · DOI：10.13031/2013.20415 · 被引用次数：196 · 研究领域：Hydrology and Watershed Management Studies、Soil and Water Nutrient Dynamics、Soil erosion and sediment transport

The presence of subsurface tile drainage systems can facilitate nutrient and pesticide transport, therebycontributing to environmental pollution. The Soil and Water Assessment Tool (SWAT) water quality model is designed to assessnonpoint and point source pollution and was recently modified for tile drainage. Over 25% of the nations cropland requiredimproved drainage. In this study, the models ability to validate the tile drainage component is evaluated with nine years ofhydrologic monitoring data collected from the South Fork watershed in Iowa, since about 80% of this watershed is tiledrained. This watershed is a Conservation Effects Assessment Program benchmark watershed and typifies one of the moreintensively managed agricultural areas in the Midwest. Comparison of measured and predicted values demonstrated thatinclusion of the tile drainage system is imperative for obtaining a realistic watershed water balance. Twocalibration/validation scenarios tested if the results differed in how the data set was divided. The optimum scenario resultsfor the simulated monthly and daily flows had Nash-Sutcliffe efficiency (ENS) values during the calibration/validation(1995-1998/1999-2004) periods of 0.9/0.7 and 0.5/0.4, respectively. The second scenario results for the simulated monthlyand daily flows had ENS values during the calibration/validation (1995-2000/2001-2004) periods of 0.8/0.5 and 0.7/0.2,respectively. The optimum scenario reflects the distribution of peak rainfall events re...