I have inherited a MODFLOW-model, with a complex stream network defined with the SFR2 package. The model checker reports that many of the stream segments have the error "ELEVUP or ELEVDN is below a cell bottom elevation...". The original MODFLOW model uses MODFLOW 2000, which reported the error, but would run regardless. However, when the version is changed to MODFLOW 2005, the model terminates with error due to "reach altitude error" (as written in the .out file). It is important that the model can run with MODFLOW 2005.

Is there a way I can force MODFLOW 2005 to run the model despite the reach altitude errors, (like MODFLOW 2000 apparently can), or do I need to change the stream elevations?

Any insight would be greatly appreciated.

]]>I have a question regarding boundary condition set up. I am working on a regional model of an large aquifer field which is used for drinking water purposes. Hydrologic and hydrogeologic conditions are at this stage of the research verry clear. We are dealing with open aquifer field where boundary condition is representing inflow to the aquifer from surrounding sedimentary formations.

We have calculated the infow using National groundwater recharge model and at this stage we have data of infow (Q [m^3/s]) for every cell of the boundary condition. Is it possible to calculate the needed hydraulic head in order to simulate the boundary conditions as constant head?

]]>I have a question on the LPF package.

Why is the specific storage and speficific yield buttons unavailable when a steady state model is selected? With visual modfolw that I have been using until recently one can assign specific storage and speficific yield values to either a steady stae model or transient model. However, GMS would not allow me to do that with a steady state model. Is there another way of assigning these values when a steady state model is selcted?

Regards,

Brenda

]]>I want to use evapotranspiration data sets in my MODFLOW setup. I am having actual evapotranspiration (AET) datasets. But, I am not sure of using directly these AET datasets as a input in my model.

As per my understanding, MODFLOW needs only evapotranspiration through root zones. But, If I use AET, it includes evaporation from soil, water and transpiration from vegetation. I think I should not use this AET. Maybe I am wrong also. If I should not use AET, what evapotranspiration value I should use in my model. I request you to kindly help me in understanding this concept in a better way. It will be a great help. Thanks in advance.

]]>The purpose is infiltration to prevent consolidation of clays (but that's just for info).

....and found the answer myelf. :-P

]]>Would you please helps me how to find the surface water routing process( SWR1)activated when using Modflow 2005 with UZF package. I'm trying to model runon/runoff interacted with unsaturated flow profile In tiny grid. Please find the SWR documents

https://pubs.er.usgs.gov/publication/tm6A40

Thank you

Adel

]]>If using CHD package, can't input them for each layers.

How can I input ?

]]>
However, when i was trying to run the stochastic model, which took the recharge rate of the study area as the parameter with different probabilities. I defined the key value of the recharge rate, and run it stochastically, everything went well. I got the results of these realizations. Then i was trying to do the risk analysis, in order to generate the probabilistic capture zone distribution. However, it showed that"**MODPATH had errors, cannot read error files**", that I can not get the results of the probabilistic capture zone distribution.

Do you have any idea that what's the problem with it? As it's the essential part of my graduate project, it's really important that I should fix the errors ASAP. Your kind help and assistance would be greatly appreciated.

]]>I'm having a problem related with assigning specified flow boundary conditions to my UGrid / Modflow-USG model. The error appears when I do the '' Map to MODFLOW'' option while converting my conceptual model to UGrid numerical model. I have read the helping document saying that If you want to use ''Specified flow boundary condition'' the UGrid must be a stacked grid. A stacked grid is one in which there is no vertical discritization of layers and the horizontal discritization of all layers is the same. (i.e. the Index of Vertical Sub-Discretization (IVSD) in the UnStructured Grid Discretization (DISU) package could be set to -1) (See the Figure attached).

Firstly, I did not understand what this means and how to find the IVSD in the DISU package and set it to -1 to be able to use specified flow boundary condition. In my model there are 2 groundwater divide boundaries which must be zero flow and 2 formation boundaries where the aquifer feeds from neighboring formations with a specified flow value. If I ll have to change my specified flow bound. cond. with something else or If there is a way to use them, could you please help me to find the solution?

Thank You!

]]>Anyone have an Idea how to convert a modflow2000 model to modflow 2005. I simply tried to use the modflow global options and change the version from 2000 to 2005, and saved the project with a new name. But when I ran the Modflow I got this error message: FIRST ENTRY IN NAME File MUST BE "LIST" . MODFLOW terminated with error!.

Thanks

]]>

As I am new to the MODFLOW package, what is the simplest process for turning TINs (some do not cover the entire extent of the model) into a 3D block to model groundwater flow via particle tracking.

I have attempted fill between tins and horizons, however, nearly all solids appear as below, mishapen and not extruding between the TINs as expected.

]]>

My data, however, is a blanket of worked seams and lacking any tunnel or shaft data (the hope was to use CLN utilising this network data). I am hoping someone may have some experience with battling similar issues? The data is all vector data used in ArcMap and I've noticed that some files will transfer into MODFLOW easily (such as DTMs), yet others like TINS do not.

During the initial process, I have a few questions I hope someone with more experience may be able to answer.

1) How to site the workings at their respective heights using Arcmap shape files and TINs. (MODFLOW doesn't seem to like TINS but does recognise them). The shape files are divided by 20-50 meter barriers of solid seam (walls of major blocks), would this kind of shape file transfer when placed into MODFLOW easily distinguish between Open channel flow for the known workings, and a general value for the aquitard wall materials.

2) Once the workings are in place at their respective depths, is there a way within GMS to allow all surrounding lithologies to be generalised (i say this as the local geology is cyclotherms and is made more complex by the inclusion of coal mineworkings). I've included the 3D geology image below, exhibiting the space between the coloured seam workings.

3) Would the easiest way to produce connecting shafts between the various seams be by using wells?

Thanks in advance,

M

]]>I am trying to generate velocity vectors in a density dependent model. The GMS is displaying error, pic of which is attached below. I have been generating velocity vectors and never faced any such problem. I am not able to work out solution to this problem. Any help would be appreciated.

Thank You

]]>

Thanks in advance

M

]]>Thanks in advance for the responses.

]]>we are trying to create a simple steady state and transient simulation of an area with a lake present. we have interpolated the lake bathymetry to a tin, however the model always ends in an error. without the lake boundary condition the simulation runs fine. are there specific instructions how to set up the lake bathymetry? should we use elevations above sea level or relative? thanks

]]>From the barrier fact sheet:

-hydraulic conductivity equivalent: 1E-10 m/s

-thickenss : 0.01 m

The thickness is in the direction of the flow as described in http://www.xmswiki.com/wiki/GMS:HFB_Package.

I get HC = K/T = 1E-8 m/s/m

How Modlfow (LFP) use HC in resolving the flow equations without the barrier thickness?

Why not set HC to the hydraulic conductivity equivalent value?

Thank you

daniele

]]>- What could the reason be for the non-convergence of the MODFLOW 2005 forward run?
- What is the reason for differing results between the MODFLOW 2005 parameter estimation and forward run (head and dry cells)?

I'll be appreciative for any thoughts.

]]>

I have never used modflow-usg before.

I am wondering if MT3DMS is compatible with the Modflow-USG "Ugrid" flow model and the CLN well package?

In other words, if I create a flow model using the UGrid in Modflow-USG and wells using the CLN package, would I be able to simulate solute transport using MT3DMS in GMS?

I look forward to hearing from you.

Cheers

Mahmoud

]]>