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About julian.weir

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  1. Yes, it is the observations that I cam comparing. There are differences between the NWT and the USG solutions, but not huge, depending on how the unsaturated cells are treated. There looks to be a consistent bug with how GMS interpolates head to the observation location. I have also received a message from someone else who has experienced the same problem when the observation elevation is specified by either 'Z location' or by 'Use well screen'. And as you have found, setting the option to 'By layer number' does not have this problem. In my case I have hundreds of observations, so it will
  2. Thanks for that idea. I have trialled using GMS 10.4 (with MODFLOW-USG 1.5, 2019), GMS 10.3 (with MODFLOW-USG 1.4, 2017) and GMS 10.2 (with MODFLOW-USG 1.3, 2015), and all gave about the same solution, and all had the same large differences between MODFLOW head values and corresponding observations reported by GMS. So, it still looks to be a GMS bug. I'll see what the support team can find.
  3. Hi all. I have recently set up a MODFLOW-USG model, one that was previously constructed as a MODFLOW-NWT model (and worked very well). I have found that the values of heads in some cells calculated by GMS are vastly different to the heads in the cells calculated by MODFLOW. Has anybody found this before? It may have to do with interpolating between unsaturated and saturated cells. I’m not sure if it is a GMS bug or my operating error. I have contacted GMS support and they are looking into it, but they are extremely slow at responding. Any tips would be appreciated. Thanks.
  4. I had the same problem, and the helpful guys at USGS helped me solve it. I was able to replicate the NWT solution by setting all layer types to 'Convertible Upstream' (in the LPF Package options) and using the '(1) Newton with Delta-Bar-Delta' nonlinear solution method (under the SMS solver options). When theses are selected, it reverts to the equivalent of MODFLOW-NWT, and I understand that the cell wetting options are not used. Hope that helps.
  5. Thanks Alan, that's helpful to know.
  6. Hi all, I am attempting to run a MT3DMS simulation (and eventually SEAWAT, too) with MODFLOW-NWT, and MT3DMS reports this error: Error Reading Flow-Transport Link File Possibly Caused by: 1. Incompatible Styles of Unformatted Files Used by MODFLOW and MT3DMS; 2. Unformatted Flow-Transport Link File Saved by Verison 1 of LinkMT3D Package Which Is No Longer Supported by MT3DMS. Has anyone come across this before and has a suggestion on how to fix? It may be related to a GMS bug (I am using version 10.3.5, 64-bit) as I have tried an older model that successfully
  7. I have had a similar error return when mapping coverages to MODFLOW. I'm waiting for technical support to reply, but it is an error that takes a while to reproduce due to the large model.
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