Modeling subsurface drainage flow of a tile-drained small watershed using DRAINMOD
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The watershed-scale simulation model DRAINMOD was used to model the hydrology of a tile-drained Indiana agricultural watershed. The goal of the research is to study whether local measured soil data can be replaced by published SSURGO soil survey data, and the Indiana Drainage Guideline can replace actual system design data in simulating the hydrology of the watershed. Field-scale DRAINMOD model output was compared to gauged field data, and then applied to the watershed-scale using a GIS-integrated DRAINMOD for simulating the hydrology of tile drained watersheds. A sensitivity analysis was performed to determine the parameters that would most affect drainage flow at the watershed scale. The parameters that were determined to be the most effective in changing the model output were drain depth, drain spacing, and saturated hydraulic conductivity. Simulations show that DRAINMOD was able to simulate the hydrology of the gauged watershed with reasonable accuracy when tile drainage system design was based on the Indiana Drainage Guidelines (IDG). The use of published soil hydraulic properties, guidelines for drainage system design and the understanding of parameters that are most effective in changing drainage flow enables the user to predict drainage flow at the watershed scale with a limited set of available input data. © 2005 American Society of Agricultural Engineers.
author list (cited authors)
Sammons, R. J., Mohtar, R. H., & Northcott, W. J.