iMOD User Manual version 4.4 (html)

12.24OLF Overland flow package

The overland flow package defines the elevation (L) above which outflow of groundwater will occur when exceeded by the groundwater head. The package simulates the effect of outflow of water across the land surface. The water is discharged out of the model and does not return to the groundwater. The OLF elevation may be determined at a few centimetres above ground elevation to represent shallow ponding caused by small obstructions against outflow. The flow rate of the OLF package is calculated assuming a fixed resistance against outflow of 1 day. The OLF package is not available in MODFLOW, however, the OLF-concept can also be applied by using the conventional DRN package, see Section 12.19. The modeller might prefer to use the OLF package because 1) the assigned resistance value is cell size independent and 2) in the model output the resulting volumetric budget are kept seperate from e.g. the DRN volumetric budgets.