TUFLOW Message 2044
ERROR 2044 - 2D HX cell ZC level is below 1D bed level.
WARNING 2044 - 2D HX cell ZC level is below 1D bed level.
WARNING 2044 - ZC level of ",a," at 2D HX cell is below interpolated node bed level of
The ground level of the 2D cell (ZC level) is below the 1D bed level. 2D cells selected by 1D/2D (HX) interface lines must be at or above the bed level of the 1D channel. This error usually occurs when the 1D/2D interface line (HX line) passes through a depression that is lower than the bed levels of the 1D cross-sections.
The linking method when using 2D HX boundaries is described here: Tutorial Module 11, 1D/2D Links
For a HX type connection, the water level from the 1D is transferred out to the 2D cells. If the 2D cells are below the 1D bed level, when the 1D model is dry the water level is set to the invert of the channel. If this water level (invert) is transferred from the 1D to the 2D, this would result in a flooded 2D cell. This could potentially allow water to be "created" in the model.
This error has been known to occur in situations when an Estry node is linked to an ISIS node, that is also linked to 2D HX cells for TUFLOW builds prior to 2012-05-AE. In these cases, the 1d_to_2d check layer showed the HX cells were incorrectly linking to Estry and ISIS rather than solely to ISIS.
The 2D cell elevation controls when water can "spill" from the 1D to the 2D. Thick breaklines should be used to ensure that this elevation is correctly set in the 2D. This is documented in the tutorial model for 1D/2D linking here: Tutorial Module 11, 2D breaklines.
ISIS-TUFLOW models linked via the ISIS-TUFLOW-PIPE link should be simulated with build 2012-05-AE or later where the problem with incorrect linking of nodes has been resolved.