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Sean Czarniecki

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Sean Czarniecki last won the day on August 4 2009

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About Sean Czarniecki

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  1. problem horizon to solids

    It could be that some shallower boreholes are throwing things off for you if they don't go down deep enough to define your layering. I know that in the past I have made polygons in my cross sections which extend downward from a shallow borehole to help fix this issue. I can't say it will work for your situation - you may just have to either put in a dummy borehole or remove the shallow one.
  2. Model Checker with SFR2 Package

    I second the suggestion, although the MODFLOW output file tells you this immediately. The model crashes and the elevation errors are listed right at the end of the output file.
  3. MODFLOW-USG & CLN cells staying wet

  4. SFR Package - Arc interpolation control

    Thanks again - I spoke with my GIS guy yesterday and it seems that getting the segment starting and ending elevations wouldn't be that difficult. I'll just have to figure out how best to get them into GMS. Did you do it via cut and paste into the dialog box for the segments, or through a MODFLOW input file? Right now, GMS looks to a binary file for the array. I think I was recently successful in getting an input file to ignore the binary file, but in another case, I was not successful (I don't recall the details on which package it was), so just curious as to which way you went.
  5. SFR Package - Arc interpolation control

    Thanks, Bruce. I totally agree that the SFR2 package is better than drains or rivers when you are actually trying to get the correct water balance in a watershed. That's why we're using it. The issue is that the region is mountainous, so using one segment for a 30,000 m long stretch of stream/river doesn't put the streambed at the right elevation for much of that length. I like your thought of using GIS, but like you said, it would be pretty high-level work.....I may have to go that route though if I don't figure out a better way to do this in GMS. Do we know if there is an upper bound to the number of SFR2 segments allowed? Without accounting for elevation changes, I will have around 100 segments in the drainage basin. If I wanted to be precise in accuracy, I could easily get to 1000 segments (I wouldn't likely if I did it manually, but if I went the GIS route, I would shoot for high accuracy).
  6. SFR Package - Arc interpolation control

    Okay - I see what you are saying. While there is no actual interpolation which applies a stream bottom elevation to a cell, there is an "internal" SFR2 interpolation which sets the stream bottom in the cell for use during calculations (as evidenced by errors which show up in the output file when a stream bottom elevation is below the bottom of a cell...and by the calculated depth of water in a reach [cell] in the istcb2 file). I might still consider putting this in the GMS development feature request if I have time in the near future. Based on what you are saying, I would want Z elevations from the arc's nodes and/or vertices used to generate segment elevations, as that is the item which is painful to put into the dialog boxes (you can easily put in similar hydraulic properties for all of the arcs, but the elevations are all individual entries). I'll think about what might work best.....there may not be a big push to get that done. This is the first model I've worked on with a large number of streams. I'm sure that most modelers don't go this route too often. Thanks again!
  7. SFR Package - Arc interpolation control

    This may end up under the GMS development request forum, but I'll first see if I'm missing something. I'm using the SFR package for the first time. I've taken one of my stream segment arcs and input the upstream and downstream elevations. When I map to MODFLOW, it would appear that there is limited control over the interpolation. This is in a mountainous region, so the terrain does not necessarily stay at a steady gradient. This causes my stream to often be at a higher elevation than reality. From what I can tell, my only option is to break up the segment into many smaller segments. This is quite painful. I had considered if I could do anything manually in the input files, but the SFR package information goes into a binary file. Rather than breaking up the segment, wouldn't it be easier to change the interpolation to work with the vertices and allow the user to just change the vertex elevation? Maybe it does this already, but I don't see it discussed anywhere....and since all my vertices are at a Z elevation of 0 (and the interpolation isn't affected by that), I'm thinking that they are ignored. Any thoughts on making this process easier than breaking up my segments into many smaller segments? I might seriously need to make segments go from one cell to the next in many locations. Thanks!
  8. MODFLOW-USG & CLN cells staying wet

    Thanks - I read that, but it wasn't as clear as I would have liked it to be, as other versions of MODFLOW have convertible cells, but once they get dry, they stay dry. The text in the manual doesn't make it clear (to me) that it applies to more than just the CLN cells (and neighboring GWF cells). I guess it does! Thanks again for the response!
  9. MODFLOW-USG & CLN cells staying wet

    I've been given a MODFLOW-USG model (including use of the CLN package) whereby the upper layer is Convertible Upstream. The model won't converge if the layer is just set at Convertible. Fine. While I'm fairly new to USG (still reviewing the calculations/equations at this point), I can accept that the model needs that layer to be Convertible Upstream. My real issue is that cells in that layer which would normally be "dry" (head below the bottom of the cell), stay active and report back the head (and use in contouring) which is below the bottom of the cell. If the layer were confined, I could understand it, but I'm guessing that there is something that I don't know about "Convertible Upstream" which is keeping these cells active, even though they should be dry. Anyone have insight into this? I don't really see it as a problem (the model results seem correct and water just passes through the cell to get to the lower layer), but rather something I'm curious about, as I'm not used to seeing "dry" cells stay active before except when modeling the layer as confined. Thanks!
  10. Potential Bug in CLN Well pkg?

    I had a transient model set up where each of my well flows were going to be the same for each stress period, so I checked the "Use previous" box in the CLN Well Package dialog. When I got my model results, the first stress period had the correct total flow in the output file, but all the other stress periods only showed the flow from the first well. I tested things further by unchecking the "Use previous" box for other stress periods. The correct total flow was shown for those stress periods. I am now running with all stress periods not having the "Use previous" box checked. Just an FYI. This is GMS 10.2.5 build date of May 17, 2017.
  11. Importing MODFLOW-USG files

    I have a model that was created in Vistas which I'm attempting to convert over to GMS. Note that the original model did not include nested grids, so the node number should be the cell number. Anyways, I have the grid set up and was able to get the recharge in. However, the source/sink files (drn, riv, str, etc.) use nodes. I attempted to drop the information into the MODFLOW files, but I get the error that it wants to look to the HDF5 file for the data. How can I get around that? I put in a test drain, saved the file (the data apparently went to the h5 file)....but when I tried to comment out the reference to the h5 file and attempted to add/read in a couple more drains in the MODFLOW file, the model still pulled in the data from the h5 file. I thought that was a bit odd. Anyways, I have all of these node-based points which I should be able to read in, but can't figure out the best way to do it. Any thoughts?
  12. MODFLOW-USG: Recharge Mapping

    Just as a follow up based on your concern, the "thin upper layer" can be as thick as you want it to be to avoid that issue you mention. You can design your layers to meet your needs. Could take a little time, but shouldn't be too bad. Try sketching it out on paper first to visualize how to do it. First the way it currently looks, then with new layer divisions and material properties. Just a little imagination and it will work.....
  13. MODFLOW-USG: Recharge Mapping

    Can you make the extension of the thin Layer 1 basically the same material/properties as Layer 2 such that you don't have to inactivate it. For example, make your outcrop Layer 2 one foot thinner, and extend Layer 1 in that area (one foot thick)....then make all properties the same as Layer 2 (need to make sure that your vertical properties work such that flow doesn't get held up at the boundary between layers). Just a thought.
  14. Particles from a selected well

    Well, unless things have changed (I haven't done this in a while), it doesn't matter if your well is screened in the middle of a layer/cell. For MODFLOW, the well is assumed to be across the entire cell. However, you can release particles in the middle of the cell to better simulate things....although it won't be that accurate inside the cell. So you can release particles in the cells in the two layers by selecting those two cells and manually placing particles at certain locations in the cell. I don't know if you can do much more than that.
  15. Particles from a selected well

    Select the cell(s) with the well(s) and you will be able to generate particles and tell it the tracking direction.