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ARS Home » Research » Publications at this Location » Publication #163528
Title: EVALUATION OF GLEAMS AND RZWQM UNDER DIFFERENT SOIL MOISTURE CONDITIONS

Author
item CHINKUYU, ADION - VISITING SCIENTIST
item MEIXNER, THOMAS - UNIV. OF CA
item Gish, Timothy
item Daughtry, Craig

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 3/7/2004
Publication Date: 5/1/2004
Citation: Chinkuyu, A.J., Meixner, T., Gish, T.J., Daughtry, C.S. 2004. Evaluation of GLEAMS and RZWQM under different soil moisture conditions [abstract]. 2004 BARC poster Day.

Interpretive Summary:

Technical Abstract: The Groundwater Loading Effects of Agricultural Management Systems (GLEAMS) model and the Root Zone Water Quality Model (RZWQM) were used to predict daily nitrate-nitrogen (NO3-N), orthophosphorus (PO4-P), atrazine (2-chloro-4-ethylamino-6-isopropylamino -1,3,5-triazine), and metolachlor {2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)-acetamide} concentrations and losses in surface runoff from two agricultural fields: one with and one without seepage zones. The results of the study show that GLEAMS and RZWQM using default input parameters were not capable of predicting NO3-N and PO4-P concentration and loss in surface runoff from the fields with and without seepage zones. GLEAMS and RZWQM using default input parameters predicted atrazine concentration well, but poorly predicted metolachlor loss in surface runoff from both fields. Based on the different model evaluation techniques used in this study, both calibrated GLEAMS and RZWQM performed relatively well in predicting NO3-N, PO4-P, atrazine, and metolachlor concentration and loss in surface runoff from fields with and without seepage zones. However, RZWQM performed relatively better than GLEAMS in predicting surface runoff, while GLEAMS performed better than RZWQM in predicting nutrient and pesticide losses in surface runoff. Additionally, since neither model perfectly simulated nutrient and pesticide losses from the field with seepage zones, their ability in water quality modeling for such fields will be compromised and further model development is justified.