Groundwater Modeling

Aquifer Modeling Assignment

Groundwater Modeling 4:GW-3 TipsGroundwater Hydraulics

Daene C. McKinney

1Setup Part (a)Create the working directoryC:\temp\P20a_workDownload the GW-3.zip file (from class webage)Un-Zip the GW-3.zip file to get the file P20a.gwvPlace the file P20a.gwv in the directory C:\temp\P20a_workOpen the model P20a (just double click on the P20a.gwv file)Run the model P20a P20a.GWVWhen you open the P20a.GWV file, you should see :

P20a.GWVWhen you run the P20a.GWV file you should get a solution that looks like:

Setup Part (b)Create a new working directory named P20b_workC:\temp\P20b_workKeep a separate working directory for each part, so you can back up if you make a mistakeCopy the file P20a.gwv to the directory C:\temp\P20b_workChange the name of the file to P20b.gwv Open the model P20b (just double click on the P20b.gwv file)Setup Part (b) Cont.Select MODELS PATHS TO MODELSSet working directory to:C:\temp\P20b_Work

Part b Impermeable CapCreate the Impermeable Cap:Select: Props RechargeSelect: Props Property Values Matrix Editor

Impermeable CapChange the Recharge values for appropriate rows and cells from 6.34e-008 to 0.00e+00 in the cells representing the Impermeable Cap

Note the zerosRecharge for Impermeable CapYou should end up with a Recharge distribution that looks like this:

Transient Model SetupConvert the model to a transient model with 1 stress period

Stress period TypesSet: Stress Period Type to 1 (for transient)

Set up the Stress periodsStress period length = 972,000,000 seconds (= 30.82 years)20 time steps Time step multiplier of 1.5

Specific YieldSet specific yield = 0.28

Initial Heads for Part (b)Select: Model MODFLOW Package OptionsSelect: Initial Heads tabSelect: Initial Head Location: Read Heads Directly from Binary Head Save FileSelect: BrowseSelect: P20a_Assign.hds fileNoteResult Last time step Part (b)Results for the last time step should look like this.

Next Time Step Ctrl+Shift+NPrevious Time Step Ctrl+Shift+PSetup Part (x) x= c, d, e, f, gCreate a new working directory C:\temp\P20x_workMake a copy of the file P20x-1.gwv (x-1 = previous version)Place the file P20x-1.gwv in the directory C:\temp\P20x_workRename the copy P20x.gwvCopy the file P20a_Assign.hds to the directory P20x_workSelect: Initial Head Location: Read Heads Directly from Binary Head Save FileSelect: P20a_Assign.hds file

Part (c) Slurry WallWhats a slurry wall?Slurry walls are non-structural barriers (Cutoff Walls, Slurry Trenches) that are constructed underground to impede groundwater flow. (www.slurrywall.com)

Part (d) Drain BCIn the table, the elevation is the stage and the last column is the "conductanceFll in the "Drain" BC form as:Stage: Elevation from tableWidth: 1Length: 1Thickness: 1Hydraulic Conductivity: 10This gives a "Conductance" = 10 ft2/sec

cruxper.comPart (x)What solution does your team recommend?Feel free to suggest solutions that are modifications of those suggested here or have not been discussed in the assignment or these slides.