This post outlines the improved HydroGeoSphere restart functionality, designed to simplify resuming a model run after unexpected termination. Previously, restarting required modifying multiple input files, rerunning grok.exe, and manually appending outputs. Now, with the automatic generation of parallelindx.dat, restart_file_info.dat, and prefixo.restart, the process is much more efficient.

This post introduces a detailed tutorial on integrating PEST (Parameter ESTimation) with HydroGeoSphere (HGS) for automated parameter estimation. The tutorial walks through the structure of PEST input files and guides you on how to incorporate them into your HGS models. It's designed to help you run parameter estimation using PEST, though it doesn't cover advanced PEST modes like Tikhonov regularization or predictive analysis. The tutorial is based on the Abdul verification problem and includes all necessary input files.

This post covers a useful workflow for renaming large groups of sequentially titled files, such as HydroGeoSphere’s binary PHGS output files. This process is particularly helpful when working with HSPLOT, which requires input files to be numbered sequentially starting from 1 (e.g., 0001, 0002, 0003, …n).

This post introduces a simple method to clean up model folders without manually deleting individual files. While HydroGeoSphere typically overwrites results, there are cases where returning a model folder to its initial state is necessary—whether due to incorrect parameters, changes in output times, or preparing files for sharing.

This post highlights the time varying maximum timesteps command, which helps optimize simulation runtimes while maintaining high temporal resolution during periods of rapid model input changes. The time varying maximum timesteps command allows you to adjust timestep sizes dynamically using a simple time-value table. A sample problem demonstrating this feature, based on the "Abdul" verification model, is available for download. This version refines timesteps during key boundary condition changes, leading to approximately 100 additional timesteps and improved solution refinement.

This post describes how to use the minimum layer thickness and minimum layer thickness with fixed top elevation commands to enforce nodal elevation rules when building your model mesh or grid. These commands help prevent pinchouts, which occur when nodes in upper layers have lower elevations than those in layers beneath them—a common issue when working with large surface data files in complex geological systems.

This post describes how to use the zones from arcview for chosen elements command to define property zones using shapefile (.shp) data. This method is particularly useful for projects involving spatially distributed properties in both the porous media and surface domains.

This week, we're highlighting a newly added command: compute post simulation average. This command was designed to simplify coupling PEST (Parameter Estimation) with HydroGeoSphere (HGS) by extracting average values of simulated quantities over a specified time interval and storing them in a file that PEST can easily read.

This post highlights three grok utility commands that are useful for building and debugging your grok file. These commands are particularly beneficial when you want to skip over certain sections of the code that aren’t necessary for execution during a specific run.