Nodal flux reduction by pressure head boundary condition modifier
This post describes how to use the flux nodal boundary condition modifier: nodal flux reduction by pressure head. This modifier is used when the flux rate is set higher than the available water, which can cause numerical instability and model crashes.
Zero Order Source with Partitioning
This post introduces the new zero-order source with partitioning command, added to HGS in revision 2291 (August 2021 update). This command enables more realistic modeling of gaseous species production in the unsaturated zone (USZ), considering the partitioning between the aqueous and gas phases based on solubility and water saturation.
Simple Drain and Makeup Water Boundary Conditions
This post describes how to use two boundary conditions that maintain a target head in the event that head would exceed (simple drain) or undershoot (makeup water) a specified value. Conceptually we can think of these boundary conditions as one-way boundary conditions where water can only enter (makeup water) or exit (simple drain) the system and are active only when the target value is reached. We find these two boundary conditions very useful when trying to represent water management scenarios.