I am not a constant user of GMS so I am often re-learning data processing techniques. I am looking for help with a procedure to accomplish the following objective.

I have a 10 layer, steady state flow model of a coastal plain. The top layer predominantly represents a confining clay layer (material 1 in brown) with several small discontinuous regions where the underlying aquifer is exposed (material 2 in green) and some inactive regions (in red). Regions where the underlying aquifer are exposed have specified values for recharge (using polygon feature objects derived from shapefile). Other BC's are defined on the top layer: (CHD for ocean - in cyan; rivers in blue; drains appearing only in material 2 - not shown).

I would like to specify a constant head in layer 1 equal to (TOP-1m) for every cell where clay is present but not interfere with other BCs subject to the following constraints:

If (TOP -1) > BOT,

Constant head = TOP - 1

Else

Constant head = BOT + (TOP - BOT) * 0.1

Any help on a process for accomplishing this task would be greatly appreciated.

Thanks

Ted

]]>have anyone used GMS and SEAWAT-2000 together. Any suggestion on the best way to simulate seawater intrusion in a costal aquifer using GMS (version 6).

Have a nice day,

Marco.

]]>i'm working in an unconfined aquifer (convertible layers) and saline intrusion. i think that this is a problem of boundary conditions, in particular in the top of the aquifer and in the bottom, but i m not sure. if you have suggestions it d be really helpful for me

thanks

Ilaria

]]>

is it possibile to individualize the flow vectors (the arrows) in the domain of GMS ?(in attached an example to show what i mean..)

Thanks

]]>Is there a way to obtain a time series of the variation of constituent concentration at a selected grid cell in MT3DMS?

Thank you,

Lalith

]]>I have model developed in USG with the stream package setup (not the river or stream routing packages). I am having problems with the steady state model runs not presenting the simulated stream flow results back to the arcs in the coverage file.

Setup, In layer one we have various streams arcs built into the model from the conceptual model methods as per usual. We have several known observation flow gaging station results whose data I have input as arcs and arc groups in the conceptual coverage file. Observed flow checked and observed flow rate entered plus the observed flow interval. These were assigned into the model through, map to modflow, as per normal methods. I have gone in the Modflow-USG observation file and generated the flow observations in the Generate PEST observation data. No problems with well using this method. I can see the entered data in the "FlowObservation" and "FlowSample" dialogs. I run the model and we do not receive the results of the **simulated **flows back in the coverages file. the simulated flow is zero at my specified observation flow targets. This is looking at the conceptual coverage stream file attributes. I know this is wrong because I can go into the model output file and check the stream nodes adjacent to the observed flow targets and I have results.

I would like to fix this problem or get some feed back from others, because I would like to try and run this in PEST to calibrate conductance and other parameters etc... But if the simulated results are not reading I don't believe this will work in PEST.

With in regular modflow tutorials I have no problem setting this up and getting simulated results back in the conceptual coverage stream file.

Cheers,

]]>Do anyone know the cause of the error message: Index is out of range . This happens usually when i convert my conceptual model to MODFLOW. My model is relatively big one. it consists of 5 layers with about 55000 active cells. The maximum number of stress period, which I can define is 27. If I try to increase the Stress periods number I get this error message. is there a limitation for the Stress periods number depending on the number of active cells or the complexity of conceptual model.

Thanks

]]>I am trying to use pilot points calibration as the tutorial https://www.youtube.com/watch?v=kaFgRRPsifo to groundwater model calibration in my case study.

Unfortunately, I got an error like the attached file. Does anyone have the experience to solve this issue? please help me.

Thank you very much,

An,

]]>

Greetings everyone,

I am somewhat new to GMS and have made my way through a number of the tutorials, but I am struggling with setting up a SEAWAT model. I want to create a 2D cross section of a coastal aquifer with the elevation of the top of the model decreasing from left to right, reaching 0 meters at the shoreline (MSL). I have a measured elevation profile (in .txt format) of the study area (X and Z). My question is how to set up a 2D cross sectional domain in the X and Z direction (Y would be 1 meter into the page). Is there a way to define the model domain in cross-sectional view using the conceptual approach, and import the X and Z data to define the top of the model? I suspect the scatter point tools will be used (Interpolate to->MODFLOW Layers) , but it seems not possible to define the model boundaries and boundary conditions in cross sectional view.

Thank you!

]]>I will be trying to develop cross sections and a solids model from 100 - 200 boreholes. I wanted to see how robust the auto process was in GMS. So I used the data from the TPROG tutorial with the Stratigraphy Modeling-Horizons and Solids tutorial. When I got to the Horizons -> Solids step I got the following error. I double checked that I completed all the steps a couple of times but always got the same result. Any bright ideas out there?

TIA

Ted

]]>I’m trying to run a transient model for ten years from 2006 to 2016.The flow budget in the aquifer is negative, Checking the information such as hydrodynamic coefficient shows that the hydrogeological condition changed after 2010 becuse of drawdown. Now I want to define the K (hydraulic coefficient) and Sy(specific yield) for two period separately. How can I define that in GMS?

Any suggestion will be appreciated....

Best Regards

Mina

]]>Any suggestions on a strategy for mapping the heads and the BCs to the local model are much appreciated.

Ted

]]>This is more a fundamental GW question than modeling. Does MODFLOW steady state modeling use the Specific storage (S) in its groundwater flow calculations?

I have an inherited steady state MODFLOW GW model where Specific storage (S) is left as 0 but model works. In the model, the hydraulic conductivity, longitudinal dispersivity, and porosity values are specified. Just trying to understand if the simulation results are correct.

Your responses and suggestions are very much specified.

Thank you,

Lalith

]]>I tried to create a Modflow model from Solid layers using Aquaveo GMS 10.4 but I got an error like the attached figure.

Do you have the experience to solve this error? Please help me!

Thank you very much,

Yours sincerely,

T.An,

]]>1. We definitely need to be able to look at a cross-section of the dam and show head contours on the cross-section. With a regular grid, this is straight forward as long as your cross-section is along a row or column. I don't see any cross-section cutter in the USG model. With an unstructured mesh, we are used to using the control key to select a line of elements to isolate. I do not see that that hotkey is available with an unstructured grid, but it looks like we can select and isolate a group of cells and get a similar effect - either draw a box or select with a polygon. Is that our best bet?

2. Once we have the model solution, we compute a factor of safety against uplift at all the surface nodes in the FEM model - basically we need the gradient for upward flow. We have an external code that will automatically do this for an unstructured mesh by comparing heads and elevations at nodes located at the same x,y location. If we use a regular structured gridded MODFLOW, the computation is pretty trivial using the MODFLOW arrays for the centroid elevations and computed heads and the data calculator. I am not finding the same options in the unstructured grid. I realize that the grid is not required to have layers and that the computational points are not necessarily at exactly the same x,y locations, but it seems that the only way to build the unstructured grid in GMS is with layers, so if you're using the GMS interface, it's likely a layered USG. At this point, I'm thinking writing an external code or maybe an excel macro may be my only option here and I can probably steal code from the routine we use on unstructured meshes. Is there anything I'm missing in the GMS interface that could help me here?

Thanks for your advice.

]]>I am trying to model a support of excavation (SOE) with diaphragm walls along the perimeter of the site and install wells for dewatering within the site. We would like to see the drawdown curves inside and outside the site. Can anyone please give me a direction on this? We don't have a toe cut-off.

Thanks

]]>I am trying to use GMS to model a dewatering system within in excavation which has cut-off walls on all the sides. I am very new to this software.

Can anyone direct me to the right track here?

Thanks a lot!

]]>I tried to construct a Modflow model from solid data using hydrogeological boreholes data.

Unfortunately, I got an error like the attached figure. Could anyone have any solutions please help me.

Thank you very much,

Sakura,

]]>

I'm currently using the Conceptual Model Approach to assign General Head Values to my Modflow-Model. I have two main aquifers, separated by a confining unit and I want to assign different head values for each. Since my grid expands over about 500 cells in vertical direction every aquifer extends over several grid layers, but height is not consistent over the whole domain.

Is there any approach like assigning head values to materials?

Thank you a lot, Jonathan

]]>I am trying to perform Monte-Carlo simulation in a vertical slice of the aquifer (x-z plane). I want to generate around 100 realizations of the spatially-correlated hydraulic-conductivity random field in 2D (x-z plane). Then I want to solve flow and transport for each realization and analyze the ensemble of results. I explored options in GMS and this is what I found out (correct me if I am wrong):

1) Stochastic Modeling Option: It is not possible to generate 2D field (spatially varying K values) using this option.

2) Interpolation using 2D Scatter Point Tool: This only allows to generate conditional realizations (kriging). I couldn't see a way to generate unconditional realizations. Also, this tool works only in plane view, hence random field can be generated only in the x-y plane. I want to generate fields in x-z plane.

Hence, it seems my only option is to generate K fields outside of GMS, importing K fields and solving cases one by one. Please, let me know if there is any other efficient way to perform this.

Thank You

Saubhagya

]]>When I want to map my conceptual model on UGrid (Unstructured Grid) , it works till 6% and then it shows the following error:

**"Boost. Geometry overlay invalid input exception"**

I stuck in this step and I need your precious help. Any points would be highly appreciated.

Many thanks in advance for your time and help.

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