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.

]]>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.

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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

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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 SEAWAT problem with MODFLOW/MT3DMS. Flow model works fine but MT3DMS prompts error message requiring to use sink/source term. I have no wells in the problem and the only BC are constant concentrations at both sides of the boundary. Why I need to specify sink/source terms?

In this case do I need to specify negative values of ICBUND array at constant concentration cells?

Thanks for help

Speedy

]]>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

]]>

It might be very basic question but I am struggling with it. Is there a feature in GMS to display streamlines after MODFLOW simulation?

Thank You

Saubhagya

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I am currently doing a project regarding in-situ chemical oxidation of BTEX using persulfate solution, and trying to use RT3D to represent the process.

As reading the literature the reaction should be a pseudo 1st-order kinetic reaction model, but the only relevant option I found in the reaction package is the inst. aerobic degradation of BTEX which only offers oxygen as the electron acceptor. In this case, could someone familiar with the persulfate or other similar oxidation mechanisms tell how to construct the RT3D model? convert the persulfate concentration to an equivalent oxygen concentration? or should I try more options other than MODFLOW?

Regards

Dylan

]]>
I have come up with some errors when running the tute model of **TUTE: MODFLOW – Generating Data from Solids **that** **indicate “changing heads are below the bottom of cell xxx". It is so weird that a tute brings up a problem like this. Having read a thread in the forum suggesting to remove the BC of constant heads from the sources sinks coverage, I found many cells dry out with red triangular flags after a modflow run. I knew it was different from what is instructed in the tute sheet, but it seems plausible for me that without those BC these cells could dry out.

A further question is, i was constructing a more complex multi-layer solids model and tried to convert to modflow. My BCs are constant heads set on the arc of the coverage boundary, kind of surrounding my small catchment of interest, and they are definitely all below the bottom of my first, second and part of the third layer, so how to define the default layer range? (i.e. from 1 to 1, 3 to 12 as I have 12 layers in total, or 1 to 12?). PS: in this coverage I define wells, specific head, layer range for source sink and layer range for areal properties, and tick used for BC option.

The first trial I have set was 1 to 12 (dont know if appropriate), converted map to modflow, and could see the blue dots assigned from layer1 to 12 of my conceptual model. All of them indicate the some heads I define in the coverage. (Really? Does it have to be a 58 m head in the even very bottom of my rock layer of 30 m elevation?). As expected, the model warned that lots of heads were below cells' bottom. When removing all of them in sources sinks and running the model in steady state, I found it never converge. A feeling was that I did it wrong when defining BCs.

This is where I got confused. Could anyone kindly help? I am using GMS Version 10.0

Thanks for any help

Rgds

Dylan

]]>I currently have a two-layer transient model which I am trying to calibrate with PEST. So far, I am only attempting to use hydraulic conductivity in PEST. I have two separate HK polygons for the top layer and one HK polygon for the bottom layer. The parameter estimator is able to initialize all three parameters but when I actually run PEST nothing ever happens or is processed. The only thing that changes is the time running. I'm not sure what I am missing that would prevent PEST from actually running. Does anyone have any suggestions as to what I may be missing?

]]>I am using GMS 7.0 for MODFLOW simulation with a system having

While the model checker was operated, it showed two errors namely “changing head boundary is below the bottom elevation of cell” and “starting head is lower than the bottom elevation of cell” which were fixed with “Fix layer errors” button by selecting the average method. Then the model was run under steady state condition and the contours were generated. After this, the model is responding no more. When I am trying to view the head contours, or view the water table in side view or view the flow budget, **a message less error (a yellow triangle with exclamation mark within and “OK” sign at its bottom)** is coming every time in the window and it lies there despite my several attempts of closing it which leads to the forceful shutdown of the system. please some body help me sorting it out.

Attaching the snapshot.

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1. Can someone please explain further why we choose the **Standard finite difference method** for both the **Sequential anaerobic degradation and BTEX degradation with multiple electron acceptors****, MMOC for the Rate-limited sorption reaction, MOC for both Instantaneous aerobic degradation** and **Double-Monod model, 3rd order TVD (ULTIMATE) **for all MT3D tutorial cases, etc.

If there were relevant recommended reading resources, that would be greater.

2. In the Rate-limited sorption reaction tute, what is the meaning of changing *Max. number of cells any particle will be allowed to move per transport step *to 2 in the **Particle** dialog of the **Advection** package?

3. How to save multiple solutions as a .rts file like what it supposed to import in the Rate-limited sorption reaction tute. Because each time I ran the model it would overwrite the existing solution with a new solution of both Aqueous and Soil given a certain mass transfer coefficient. How to come up with a solution with different runs (i.e. different mass transfer coef in one solution file?

Thanks,

Dylan

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1. What happen to the right part of zone 3 with a constant recharge rate when importing csv file automatically matching zone name? The other zones are assigned correctly except for this part of zone 3.

2. In the tutorial it states the stress periods should match three changing point of recharge rate, i.e. 1/1/1986, 1/3/1986, 1/7/1986 (actually it is four including 1/10/1986). What is the purpose to set 1/5/1986, 1/6/1986 and 1/9/1986 etc. since no change takes place at these time? In addition, this should assume all the recharge polygons have the same changing points of rate over the space, so what if we have different change in time of these zones, say 1/3/1986 for zone 2 and 1/4/1986 for zone 3 etc. How to set stress periods for this scenario?

]]>

The steady state model demonstrates 30 feet of drawdown, which is much more in line with what I expected.

I returned to the transient model and have adjusted the storage values orders of magnitude up and down and do not get any change in my final heads at 100 years; at least not more than a few feet.

I have tried different solver packages to see if that would adjust my heads and that didn't seem to work either.

I have tried to run the model out to 1000 years instead of 100 and this doesn't seem to have a affect on the final heads.

Is there another property or function I am missing? Any other troubleshooting suggestions?

Any thoughts would be appreciated!!

]]>

I have a MODFLOW 2000 model, which runs fine. I created MT3DMS model, which also runs fine. The problem is SEAWAT does not converge despite no error appears when I check simulation!. The message appears in mf2kerr.p00 file reads:

MATRIX IS SEVERELY NON-DIAGONALLY DOMINANT. CHECK INPUT FILES

Any suggestion?

Thanks

]]>

]]>

The OUT file states "model stopping due to reach altitude error." Upon further examination of the OUT file, there are warnings for each stream segment that "upstream elevation is equal to or lower than downstream elevation" and the streambed properties listed in the file indeed streambed elevations all set to zero.

Looking at the SFR2 package through GMS shows all stream segments ELEVUP and ELEVDN set at zero for stress period one. For all other stress periods, there is data provided for ELEVUP, but ELEVDN remains universally set at zero. I can copy the ELEVUP data from a later stress period and apply this to stress period one, but without ELEVDN data, the altitude errors still occur, terminating MODFLOW. It appears that when importing the file, GMS does not pick up the streambed elevation data.

Any help will be much appreciated.

]]>

Thanks,

Brianne

]]>- STEP 1

The simplified model is a 10x10 m grid, with only two Boundary Conditions: from CHD 1.0 m (left side) to CHD 2.0 m (right side).

As I've the **HK for an equivalent Slurry Wall** (width 1 m), I insert 3 polygon features:

1) HK representing the Slurry wall (width = 1 m): HK = 0.0041 m/day

2) HK representing the Slurry wall's holes, filled with gravel (width = 1 m): HK = 864 m/day

3) HK representing the aquifer: HK = 1.2 m/day

I check the Flow Budget for all the model (run 1):** 30.6 m3/day.**

The head value in the cells just before the HK is 1.45 m.

- STEP 2

Now I need to set an HK equivalent rapresenting the Slurry wall with holes.

I use the parallel approach (Figure_3, in the xy plane): HK eq = (HK sw x Lenght sw + HK holes x Lenght holes) / (Lenght sw + Lenght holes) = 43 m/day

I replace the Slurry wall with holes polygon with a new polygon with HK equivalent (43 m/day).

I check the Flow Budget for all the model: **41 m3/day**. Why is not the same value obtained from run 1?

The head value in the cells just before the HK is 1.23 m, less than 1.45 (run 1).

- STEP 3

I change the HK equivalent for the Slurry wall: 0.38 m3/day.

The Flow Budget for all the model: **30.8 m3/day. **

The head value in the cells just before the HK is 1.44 m.

Why the HK equivalent are so different (100 times smaller)?

What's wrong in my exercise?

Thank you

Daniele

Figure 1: HK representing the Slurry wall (width = 1 m): HK = 0.0041 m/day

Figure 2: HK representing the Slurry wall's holes, filled with gravel (width = 1 m): HK = 864 m/day

Figure 3: Formula for calculate the Effective conductivity parallel to layers