| Title: | Evaluation of the Hooghoudt and Kirkham tile drain equations in the Soil and Water Assessment Tool to simulate tile flow and nitrate-nitrogen |
| Authors: | Moriasi, D.N., P.H. Gowda, J.G. Arnold, D.J. Mulla, S. Ale, J.L. Steiner and M.D. Tomer |
| Year: | 2013 |
| Journal: | Journal of Environmental Quality |
| Volume (Issue): | 42(6) |
| Pages: | 1699-1710 |
| Article ID: | |
| DOI: | 10.2134/jeq2013.01.0018 |
| URL (non-DOI journals): | |
| Model: | SWAT (modified) & SWAT |
| Broad Application Category: | hydrologic and pollutant |
| Primary Application Category: | tile drainage effects and/or processes |
| Secondary Application Category: | nitrogen cycling/loss and transport |
| Watershed Description: | Three 13.5 by 15.0 m plots, located near the City of Waseca (and managed by the University of Minnesota) in southern Minnesota, U.S. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | Subsurface tile drains in agricultural systems of the midwestern United States are a major contributor of nitrate-N (NO3–N) loadings to hypoxic conditions in the Gulf of Mexico. Hydrologic and water quality models, such as the Soil and Water Assessment Tool, are widely used to simulate tile drainage systems. The Hooghoudt and Kirkham tile drain equations in the Soil and Water Assessment Tool have not been rigorously tested for predicting tile flow and the corresponding NO3–N losses. In this study, long-term (1983–1996) monitoring plot data from southern Minnesota were
used to evaluate the SWAT version 2009 revision 531 (hereafter referred to as SWAT) model for accurately estimating subsurface tile drain flows and associated NO3–N losses. A retention parameter adjustment factor was incorporated to account for the effects of tile drainage and slope changes on the computation of surface runoff using the curve number method (hereafter referred to as Revised SWAT). The SWAT and Revised SWAT models were calibrated and validated for tile flow and associated NO3–N losses. Results indicated that, on average, Revised SWAT predicted monthly tile flow and associated NO3–N losses better than SWAT by 48 and 28%, respectively. For the calibration period, the Revised SWAT
model simulated tile flow and NO3–N losses within 4 and 1% of the observed data, respectively. For the validation period, it simulated tile flow and NO3–N losses within 8 and 2%, respectively, of the observed values. Therefore, the Revised SWAT model is expected to provide more accurate simulation of the effectiveness of tile drainage and NO3–N management practices. |
| Language: | English |
| Keywords: | |