I have attached below images of the conceptual for flat and sloping scenario for reference. Any assistance would be greatly appreciated.

Many thanks,

Matthew

]]>I am trying to calibrate a MODFLOW model using PEST. My model has multiple layers (12). However, I do not know how to parameterize the model. Aquaveo tutorials explain it as specifying hydraulic conductivity and recharge values are negative values in different areas. However, I am not able to do this because my model is developed in such a way that these Hydro-geological properties are specified as a properties of materials and these materials are assigned to different areas in each layer. Would you please help me to parameterize my model?

Thank you,

Lalith

]]>I am running a two layer elevated aquifer in modflow with the hydraulic conductivity of the lower level reduced to a negligible value to explore the impact of elevation on the water table. The problem I am having is that water is leaking into the lower aquifer. Does anyone know of an alternative way to replicate this scenario in Modflow? Thanks

]]>I have recently started using the UZF package to simulated groudwater flow in a regional model. I firstly developed a steady state model using spatially distributed recharge from a surface model. I was using the «recharge» and the «EVT» package. With this configuration i was able to obtain a water budget with % error < 0.001%. When i replaced the recharge and EVT packages by the UZF, the water budget output file shows a line with a component called «HORT+DUNN» which i suspect to be the surface runoff flow. This component is not well describe in the USGS MODFLOW documentation. The problem is that this volume of water is only present in the «IN» part. In then creates a poor water balance ~1% to 5% error. If i remove it from the balance, the % error is good (> 0.01%).

Any idea of how to deal with this water budget component?

Regards

]]>

I have created MODFLOW model for a region near the coastline and It ran successfully in both steady and transient state. Currently there is no sink or source terms to make the model simple. Once the model achieve a stable solution, they will be added later. Then, I tried to run it in with SEAWAT and model shows the error that Memory is not enough.

I tried both Parallel, 64Bit options as well as both of them in combination but did not get any luck. The way that I ran the SEAWAT model is as follows. I assume that I did it correct but** please let me know if you have any alternative ways**.

1. Run MODFLOW in steady state.

2. Change the model and output to transient state.

3. Assign steady state heads in step 1 above as the initial heads for the run.

4. Map MODFLOW to the grid.

5. Map MT3DMS to the grid.

6. Run SEAWAT.

My model grid has 512 x 646 x 12 cells (12 layers). Number of total and active cells are 3,969,024 and 1,416,464 respectively .

Since I did not have any success in running the model in GMS, I decided to run the SEAWAT model in text based USGS format. I exported the MODFLOW model from GMS to the regular text based USGS format. However, I do not see such a format change for either MT3DMS and SEAWAT option in GMS.

1. I assume that either MT3DMS or SEAWAT does not require such a conversion. **Please correct me if I am incorrect. **

2. Also, I think that the SEAWAT name file in the SEAWAT folder that GMS produces (.swn file) may not be the correct one ** to run SEAWAT in USGS format **because the type, format, number of files and the content in the files are different. Please see the files and sizes of GMS and USGS formats of MODFLOW in the screen shots below.

I am planning to use the USGS version of SEAWAT executable and/source code to run the model since Aquaveo executable might have been customized to its data file types and may not match the requirements. **Please let me know if you have any suggestion on this.**

I very much appreciate all your thoughts, suggestions and help to resolve this issue.

Best regards,

Lalith

]]>

I have trouble modeling a square site with different BC.

at one side I have river (I put constant head as BC) and no problem in that for modeling.

now,

1) at one side I have rock (no flow coming in or out from site at this side) and

2) at other side of square area I have no BC (I mean the water can flow out of area etc)

what is the difference in modeling number 1 and 2? how to difine them in my model? my model currently have active cells in coverage so I think it means all sides I have rock, right?

Thank you,

Zara

]]>I have a MODFLOW project that I am creating with GMS for a class at UCLA, and I need to convert it to be read into the MODELMUSE software so I can submit my assignment and the TA can grade it. Does anyone know how to convert a GMS MODFLOW into MODELMUSE MODFLOW?

Steve Turnbull

cell 808-295-4998

]]>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

]]>

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!

]]>

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.

]]>

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!

]]>Thanks,

Imri Oz

]]>]]>

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.

]]>

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 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

]]>