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GMS User

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Everything posted by GMS User

  1. Is there a way to extract XY data for LPF package - Hydraulic conductivity? I know I can export XY data from Top and Bottom elevation of a MODFLOW Model, but I can only get Hydraulic conductivity with cell I,J,K reference not XY.
  2. I want to simulate a Sheet Pile with permeable holes through the whole acquifer. 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
  3. Dear Shayan, I follow these steps: 1) import Boreholes data and manually set HUG materials values, 2) create cross-section and set horizons value (manually or by auto-assign horizons), 3) create a TIN, 4) convert Horizons to Solids (Boreholes > Convert Horizons > Solids) The post is dated 2011. I cannot remember what kind of error I got and how I solve it. By the way I start building a simplified version of the model following the tutorials found in http://www.aquaveo.com/software/gms-learning-tutorials. It's easy to solve errors in a simple model. Afterwards I build a more complex one. Regards, daniele
  4. As I can't insert any thickness in the HFB coverage, the HC 1E-8 seems to me too permeable for a sheet pile. Isn't it? Do you suggest me to set the HC to 1E-8 m/s ? Thank you daniele
  5. I've read the HFB pacakge description found in http://www.xmswiki.com/wiki/GMS:HFB_Package but I'm still not understand which is the correct valure for HC. 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
  6. I've been confused by 2D and 3D Grid. I'm now able to insert the Barrier. That's ok. Thank you.
  7. Dear Sean, thank you. 1) I create a 3D Grid (I'm more familiar with standard 3D grid than UGrid, as I can use the Observation wells) with 2 layers. I Map the DTM elevation Grid Data to 3DGrid, use the Calculator to subtract the depth of the Barrier and I get a new 3D Data. How can I convert the new 3D Data in Modflow layers? If I select Modlfow > Global Option > Top elevation > 3D Data set to Grid, I set the same elevations to all the cells for both Layer 1 and Layer 2. What's wrong? 2) I substrat the depth of the Barrier in Golden software Surfer. I've two grids: the Top elevation and the Bottom elevation of Layer 1. I check the New Grid and it's ok. I load both Grid files in GMS and try to Map to Modflow Layers. When I start the Model Checker, it shows errors (Starting head is below top elevation). It's sound strange as I flag the "Starting heads equal grid top elevation". I look at the Top/Bottom elevation of some cells and I discover that Top elevation and Bottom elevation are inverted. I not able to set the correct Top/Bottom elevation to Layers! Any suggestion? I've just upgrade to version 10.1.
  8. I've a Local Model of a site that include a slope from 300 to 350 m asl. A cross-section is attached to the post. I set up a Modflow Ugrid model with only 1 layer. Now I'm asked to insert a Barrier, so I need a new layer because Barriers don't reach the bottom of the aquifer. Is it correct to insert a new layer with constant top elevation (320 m abs) and set inactive the cells where the top elevation is less than 320? The Coverage for the Boundary condition (CHD at elevation 300 m asl, see attached cross section) is to be set to Autoassign BC including lower cells? How can I set the same boundary condition if it starts at an elevation of 325 m asl and ends at 300 m asl? Thank you aquaveo-h1.pdf
  9. I've create a multi layer Modflow model (3 layers) converted from a Solid Model (LPF, material ID). The idraulic properties are assigned by means of material ID, one for each layer. a. HK_a for layer 1 b. HK_b, for layer 2 c. HK_c, for layer 3 Now I need the to include a new building with foundations below the ground elevation and above layer 2. The building foundation has a different HK_d << HK_a, HK_b, HK_c. I create a new coverage with material properties and layer range. I assign the new HK to the polygon representing the buiding. I try Map to Modflow but when I query the Modflow cells the HK value is not changed. How can I assign it to cells inside the polygon representing the buiding area? My workround is to select intersecting cells by polyon and manual assign the material ID. Thank you Daniele
  10. I've create a multi layer Modflow model (2 layers). I've a coverage (coverage 1) defining the domain. The coverage is divided in two polygons ( polygon A e B ) for setting the HK: a. HK_a, for polygon A, layer 1 to 2 b. HK_b, for a polygon B, only layer 1 c. HK_c, for the same polygon B, only layer 2 I duplicate coverage 1, coverage 1.1 e coverate 1.2. I make these assignments: -coverage 1.1 to layer 1 -coverage 1.1 to layer 2. Is it correct or there is a different approach? Thank you Daniele
  11. Thank you for your replay. I'm still using GMS 9.2.7. I will upgrade as soon as possible. I will try with "convert to 3D Mesh".
  12. I export drawdown and head values from Modflow simulation. I can get the drawdowns and head values from i,j,k triplets. As I use a variable grid size (grid refinement) is there a way to export the grid size for each i,j,k? I need to plot a cross section for drawdown and head values vs distance from a well. Thjank you Daniele
  13. I set up a new color ramp for contouring. I want to show drawdown values: blue for positive values, red for negative values and white to zero value. Is it possible to assign no color to the zero values so that I can see the raster map under the contouring layer? My workaround was to save GMS project to image file, open it in Quantum GIS and set the transparent color to white. Thank you Daniele
  14. I try a comparison between user's AppData\Roaming\Aquaveo, LLC\GMS 9.2 9.2.7\install\403D165\c:\Program Files\GMS 9.2\with TotalCmd Synchronize tools. They looks the same, except from GMS _9.2-64.msi which is only in the user profile folder. It's a little been confusing. Fore sure it's safer to keep a dup file, but is it really necessary wasting 1 GB? Thank you Daniele
  15. I' m trying to free some hard disk space. I've discovered an "AppData\Roaming\Aquaveo, LLC" folder in the user profile with more than 900 MB of data. Is it safe to remove the folder? Thank you Daniele
  16. I have noticed that different selections brings different grid cross sections. When I select the Modflow simulation item in the Project Manager before using the slice, the result is a cross section reflecting the IBOUND model value. When I select the grid item the cross section reflects the grid elevation. Is it correct? Where I can find help on this cross-section topic? Is it possible to resize the grid size without rebuild the whole Modflow simulation process? I'm interested in the z elevation. The grid elevation is set to 50 m asl while the top elevation and both the starting/computed heads are less than 5 m asl. Is it possible to limit the grid z elevation in the cross section display? Is it possible to set the material to be displayed or not? Thank you.
  17. The HC is set to 2.2 E-03 or 4.3 E-05 not to 0. How can I check the flow budget to see if the sheet pile (HC) is impermeable? In the table (picture previous post) I checked the total flow from the Flow Budget and compare it to the value without the barrier. Any difference greater than zero means to me there is a flow across the barrier. Is it correct?
  18. I checked the Flow Budget. In the attached picture I updated the simple model head chart (previous post). I shifted the barrier position by 20 m (now the barrier divides the domain by 40% - 60%). Both the "Total flow" from "all cells" and "cells across the barrier" Flow budget are the same. Total flow computed without the barrier (steady state simulation) is: 26389, the same as computed by Darcy. Total flow computed with the barrier decreases as the HC increases (see table in picture). Did you refer to that value when you suggest me to take a look at the Flow Budget? Is the barrier impermeable when the total flow (cells across the barrier) is 0? Thank you for your support.
  19. The figures is doubtless clear, but I don't understand correctly the barrier hydraulic characteristic. I attached a picture (cross section) of the simulated heads from a simple model and a chart of the head profile in different scenarios: #1. the head is computed without any barrier (color: gray)#2. the head is computed with a barrier. HC is set to 4.3 10-5 m d-1 (color: red). The HC value is obtained from technical data of the sheet pile which is set to be impermeable. #3. the is head computed with a barrier. HC is set to 2.2 10-3 m d-1 (color: green). The HC value is obtained dividing the K (4.3 10-5 m d-1) by the sheet pile thickness (2 cm).While #2 shows the impermeable behavior of the sheet pile (head is 500 m in the cell adjacent the barrier and 500 m is the right boundary condition), #3 shows a flow across the barrier. The flow cause a drop in head values (7 m, from 500 to 493 m) and seems to me not impermeable.
  20. I build a very simple model to test the hydraulic characteristic value of a barrier. The grid is 100x100 m, 10x10x1 cells. Specified head (left) = 450 m. Specified head (right) = 500 m. Horizontal K = 1 m d-1. I compared the head computed in two different scenarios: 1. inserting a barrier across the whole domain (10 cells, 100m , direction north-south)(coverage length 95 m). 2. modifing the property of the cells where the barrier is located (10 cells, 100 m). To get comparable head levels I set the HK = 0.1 (m d-1) and the barrier hydraulic characteristic to 0.0105 (m d-1 m-1). The hydraulic characteristic is obtained dividing HK (0.1) by the length of the coverage barrier (95) and multipling for the cell width (10). Is it correct?
  21. I'm not sure to understand correctly the barrier hydraulic characteristic. I've read from the previous post "in the current HFB Package, the hydraulic characteristic is always the barrier hydraulic conductivity divided by the width of the barrier,...". What is the "width of the barrier"? Is it the length of the barrier coverage? In my 100x100 grid model (10 m cell size), the sheet pile is 95 m length and the hydraulic characteristic is 5.00E-10 m s-1. The barrier coverage hydraulic characteristic is to be set to 5.00E-10/95 m s-1 m-1? Thank you.
  22. Thank you for your suggestions. I was thinking to a simple tool : blank cells (Surfer) or clip grid (Rockworks) inside/outside a polygon. The polygon could be the coverage used to define the active cells for Modflow,
  23. You understood my question. The desired effect is the one obtained by running "Interpolate -> MODFLOW Layers", but I would like not to use the command as it will affect the starting heads. I would like to compare Modflow computed heads with the ones obtained by grid interpolation. Thanks
  24. I imported a Ascii grid files created with Surfer and then I interpolated it to the 3d grid I build for Modflow. Surfer grid and GMS 3d grid have different cell size, dimensions and active cells. Everything worked fine. I was wandering if it will be possible to interpolate the Surfer grid only to the Active cells of the 3d grid used for Modflow, in order to get an overlapping countouring level. Thank you Daniele
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