Aquaveo & Water Resources Engineering News

Some of the more interesting accomplishments from the May 2012 sprint:

• Fixed over 19 bugs
• Overhauled the MODFLOW ccf file reader to be more generic
• Much progress on the MODFLOW SUB package
• Updated MODFLOW 2005 executable with the latest changes from USGS
• Mostly finished phase 1 of PEST Null Space Monte Carlo support
• Began adapting MODFLOW LGR to GMS format
• Finished several raster features including interpolation and conversion to/from other object types
• Added more "Open containing folder" commands where they were needed
• Made it so we just link to CAD files instead of saving them with the project
• Added duplication of MODFLOW array data in the Project Explorer
• Removed the interface for flow observations with the SFR package since MODFLOW doesn't support this
• Added commands to Expand / Collapse most items in the Project Explorer
• Split the MODFLOW conceptual model tutorial into two separate tutorials
• Finished the MODFLOW MNW2 package tutorial for non-vertical wells and pump capacity
• Added more bitmaps in the menus and made the old ones look better

Beginning with version 8.2, GMS can now generate velocity vectors using information from the MODFLOW cell-to-cell flow (ccf) file. Several pieces of information are required to compute groundwater flow velocity from a MODFLOW model. First, the amount of flow in the I, J, and K directions for a given cell is read from the CCF file. If a particular cell contains a boundary condition that is withdrawing water (such as a well) then the flow in the I, J, and K directions is decreased based on the amount of flow leaving the cell through the boundary condition. Next, the saturated area is calculated in the I, J, and K directions. For the I and J directions it is necessary to use the top and bottom elevations that are specified in MODFLOW's discretization package. If the particular cell is part of an unconfined aquifer then it is also necessary to get the computed head for the cell as the computed head is most likely below the top elevation of the cell. The final piece of information necessary for the calculation is porosity. Although porosity is not part of the MODFLOW inputs, using GMS you can specify porosity on a per cell basis. Once the flows, areas, and porosity are assembled the groundwater flow velocity is computed using the following equations:

Velocity.I = Flow.I / (SaturatedArea.I * porosity)
Velocity.J = Flow.J / (SaturatedArea.J * porosity)
Veloctiy.K = Flow.K / (Area.K * porosity)

To create a velocity vector data set from a MODFLOW CCF file in GMS you simply right click on the CCF data in the GMS Project Explorer and select the CCF -> Velocity Vectors command.

Conversion from CCF to Velocity Vectors

Once you have a vector data set you can adjust the display of the vectors by going to the Display Options dialog for the 3D grid and turning on the Vectors check box. If you select the Options button next to the Vectors check box you have further control over the display of the vectors.

Velocity Vector Plot in GMS

Some of the more interesting accomplishments from the March 2012 sprint:

• Posted GMS 8.3 beta
• Added two new videos to our YouTube channel on regional to local model conversion and contour options
• Fixed over 10 bugs
• Added a machine to help with nightly testing
• Added a few new testimonials
• Started on the PHT3D interface design
• Moved SFR outputs related to ISTCB2 to a separate CCF file so they don't get included in the flow budget.
• Fixed the Check For Updates command to warn if the maintenance has expired to avoid downloading an update that can't be used.
• PEST Null space Monte Carlo progress
• Came up with a fix for broken images when converting the wiki to OpenOffice
• Designed Global Mapper dynamic images
• Finished adding support for the MODFLOW Gage package
• Added a new Measure tool
• Added new Locate Selections and Zoom To Selections commands
• Simplified the MT3D Sink & Source Mixing Package dialog
• Enhanced the model checker and added tests for MT3D SSM, RCT and ADV packages.
• Held a training course in Mexico City
• Made several improvements to the Model Calibration tutorial
• Started splitting the Conceptual Model Approach tutorial into two
• Made exported shapefiles include a projection (.prj) file whenever the projection is not local

In GMS 8.2 we added the ability to export a 3D grid to a shapefile. All layers of the grid are exported, along with the active data set and the grid cell activity (IBOUND) and data set activity (dry cells) if they exist. Here is the list of the attributes that get exported:

• cell ID
• cell I
• cell J
• cell K
• grid cell activity
• active scalar data set values
• active data set activity (if it exists)

A simple definition query using the grid cell activity and K fields can be created in ArcMap to see one layer of the grid at a time. For example, the following figure shows the head solution on the third layer of the grid from the lake package tutorial as a shapefile in ArcMap.