Thanks,

Imri Oz

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I have a problem regarding flooding and wetting which makes it difficult to calibrate the model. It is representing a coastal area with thin clay layers and sandy till which we assumed to be 1 m each. The two bottom layers represent rock with the upper one being fractured and thus have a higher hydraulic conductivity. The surfaces are imported from ArcMap and ranges between 30 and 0 m. constant head and no-flow was assumed.The main problem I found is that the groundwater table is almost completely flat in contrast to the terrain.

Any ideas of packages, solvers or any tips in general, of how we can tackle the issue. We are thankful for any answers that could help us!

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Can anyone please tell me that **how velocity is calculated from flow data in GMS**(not through GUI).

Though I had already referred to the following the link:

https://www.aquaveo.com/blog/2012/05/15/velocity-vectors

,the velocity calculated by me is not matching the velocity obtained through GMS.

I had applied the following for the calculation of velocity:

** V = Q/(saturated_area*porosity);**

where,

Q is the **flow through a cell face**, obtained from ccf file,

Saturated area = (**head-bottom_elevation**)*cell_width {for unconfined aquifer}

and head is obtained through .hed file.

Thanks in advance. Have a great day!

]]>Cell elevation (based on surface elevation raster) is 14.18 m, bottom is 12.0. The mapped drain elevation is 11.3. WTH? I've deleted and recreated and mapped MODFLOW 3 times, no change.

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I have encountered an error in mapping solids to Modflow layer.

I have got an error which is mentioned in the attached figure.

I will be thankful to you if you can clear my doubt.

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I have a problem when i run Simulation and it stops in middle of running

__FAILURE TO MEET SOLVER CONVERGENCE CRITERIA
BUDGET PERCENT DISCREPANCY IS -141.2903
STOPPING SIMULATION__

__can anyone help me with this issue?__

__Thanks__

I have a issue with defining inflow rate to related cells. I have the total volume of inflow for each month (i want make a time series general head), but i dont know how i should define the head of the 2 points of inflow line & amount of conductivity correctly. (for example the volume of inflow is 110 MCM & the length of inflow line is 97 KM and Average elevation of area is 1900 m)

If anyone can help me it would be great.

]]>I have a problem with understanding the exact working system of number of time steps & multiplier when you want set a setting.

for example whats different of the time you have 3 time steps and 4 multiplier instead of 1 time step and 1 multiplier?

]]>I am currently trying to build a model in MODFLOW-USG similiar to a model in MODFLOW-NWT. My NWT model is fast and robust.

I have tried to build a similar model of the same area in USG in different ways, ending with the same problem. The model will not converge if any cells is dry. I discovered this by adjusting the recharge parameter. My USG model converged when the recharge was extremely high and no cells were dry.

I tried to "convert model to MODFLOW-USG simulation" in GMS to check if the model would converge when there was no difference in grid structure. I get the same result. I need to increase the recharge to have no dry cells and a model that does not crashes.

Can anyone tell me if the SMS solver in MODFLOW-USG can be set up in the same way as the NWT solver to handle dry cells, and how?

Martin

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I have a project file which is related to 10 years ago and it was made with gms 3.5 (modflow 4.2) but when i try to open it it will fail to translate the modflow correctly

So is there anyway that i can translate it correctly and run that model to check the results...

Thanks for reading

Regards

]]>Hi All,

I have a model in Visual Modflow Classic and trying to run WinPEST using concentration values in the objective function.

When I used head values as the objective function to estimate parameters with PEST, it ran fine. But when I use only concentration values, I keep getting an error:

"Cannot open model output file "projectname.001.COB."

I am running everything as an administrator and cannot even find a .COB file on my computer.

I've uninstalled and reinstalled the program, tried different versions of the models, and even changed the number of concentration observations to reduce complexity. I can't get PEST to run.

Anyone ever see this error or have recommendations on what to do?

Thanks so much!

]]>Is it possible to import a 2D (x-z plane) K field for a vertical slice of a heterogeneous aquifer? Or my only option is to paste layer-by-layer values in the LPF package?

Thank You

Saubhagya

]]>I have a question regarding the "Activate cells in coverage(s)" function. I am a master thesis student and working on a model of a local aquifer, currently supplying drinking water at a rate of 2000 m3/d. The aquifer is an esker (containing glaciofluvial soils) that lies in a small valley and has a natural outlet in the sea. I am using a specified flow boundary condition to simulate the runoff entering the esker from the surrounding outcropping bedrock. However, when only the cells in the active coverages are active some of the cells that actually have a boundary condition assigned to them are inactivated (see picture). Is there a way to correct this?

Thanks!

Edit: The problem was that I had ticked the box "Use to define model boundary (active area)" on several coverages. Using only the sources and sinks coverage to define the model boundary solved the issue!

]]>The forward transient run for 33 year was successfully done. According Project TOR I should use PEST for the model re-calibration. I defined 595 Pilot points and ran MODFLOW. Nothing is going on in the window, just the timer is working and it is signed that "Running MF2PEST - read m2p file and MODFLOW inputs and prepares PEST pst file". After waiting for 9 hours (without changes in the window) I aborted the run. During these hours the CPU worked, but in the MODFLOW folder I did not find any pst file.

Any suggestions, please! Has anyone encountered this problem?

Thanks!

]]>I am working with a MODFLOW model that focuses around a coastal aquifer system. My model extends past the coastline into the ocean to simulate submarine groundwater discharge and coastal springs. I am trying to analyze the amount of water flowing out of the aquifer along the coastline, but my values are inconsistent. I set the subaerial aquifer as one zone and the ocean floor as another zone. Then I went into the Flow Budget to see the flow from Zone 1 to 2. However, when I select the arc of the coastline, the "COMPUTED FLOW" value at the bottom strip displays a completely different value. Is there a reason why the values are so different? Do they represent different flows?

Thank you,

Brytne

]]>I am trying to numerically evaluate the discharge in an unconfined coastal aquifer with a constant head as the inland boundary. After performing SEAWAT simulation, the flow rate value in the flow-budget for any cross-section close to the inland boundary reflects only the flow below the sea-level. I also confirmed this by plotting velocity-vector plot, in which there were no velocities plotted in the region above the sea-level and below the water table. I have attached the picture for clarity. Is there a way I can get the total value of the freshwater discharge in the aquifer? I believe, a simple single-density flow model would also have a similar issue with the flow-budget in the unconfined case.

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I am running a transient model for riverbed aquifer using a one layer model with varying bottom elevation. Some of the cells are tagged dry but still the head is computed and shown for these cells. IS there a way how I can make the head not to be computed for the drycells? This is not a problem for heads but vor flow budget, heads below the drycells accounts for the variation of the storage and perturbates the real budget.

Thanks

]]>I'm having some difficulties with my current model and would love som help/feedback. I'm currently doing a SS model of a mountain terrain. The model is constructed with 10x10 m cells and 1 layer where the topography is from a 1x1m DEM and the bedrock (bottom of cells) are interpolated from borehole data. The thickness of the cells are around 10 - 25 m, and the model domain is relatively steep. Boundary conditions are a river (river packaged) and specified flux (calculated through water balance). Water flows to the river.

So the problem i'm facing is dry cells. The steep topography and the relatively thin thickness of the aquifer leads to dry cells. However, this is actually not completely wrong as our field measurements show that during some periodes some of our wells are dry. However, MODFLOW don't like this, so I'm having problem constructing my model..

So does anyone have som experience with these kinds of problems, and could spare some time helping me out? Or maybe recommend me som literature/studies?

Thanks!

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