Simulating unsaturated flow and transport in a macroporous soil to tile drains subject to an entrance head: model development and preliminary evaluation

• Published in: Journal of hydrology (Amsterdam) Vol. 254; no. 1; pp. 67 - 81
• Main Authors: Kohler, A., Abbaspour, K.C., Fritsch, M., van Genuchten, M.Th, Schulin, R.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 10.12.2001; Elsevier Science
• Subjects: agricultural soils; drainage; Earth sciences; Earth, ocean, space; Entrance head; Exact sciences and technology; Hydrogeology; Hydrology. Hydrogeology; landfills; macropore flow; Macroporous soil; Modeling; porous media; prediction; Preferential flow and transport; simulation models; soil profiles; solutes; Tile drain; unsaturated flow; Unsaturated soil; Macroporous soil; Entrance head; Unsaturated soil; Modeling; Tile drain; Preferential flow and transport; solutes; porosity; simulation; mathematical models; ground water; Agricultural soil; unsaturated zone; hydraulics; landfills; soil profiles; discharge; prediction; solution transport; drainage; soils; boundary conditions
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/S0022-1694(01)00499-1

Accurate prediction of water flow and chemical transport in agricultural soil profiles requires the use of a simulation model that considers the most important physical, hydrological and chemical processes. Two important flow-related processes in tile-drained field systems are macropore flow and water discharge from the tile drains. To better account for these two processes, we extended an existing two-dimensional model (SWMS_2D) by adding a macropore flow component as well as a Hooghoudt type boundary condition that considers the presence of an entrance head at the tile drain. The macropore component is necessary to account for water and solutes short-circuiting the soil matrix, while the drainage entrance head is needed to account for the contraction of streamlines around the drains, a feature that causes delayed discharge. The applicability of the new model to a landfill problem was examined. The simulation results, which included water flow and solute transport, compared well with other models.