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# GMS User

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1. ## GMS - How to export Hydraulic conductivity to XY points

It 's so easy. Thank you.
2. ## GMS - How to export Hydraulic conductivity to XY points

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.
3. ## Differences between computed and calculated HK equivalent

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
4. ## Modflow - model checker err

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
5. ## Hydraulic characteristic in Horizontal Flow Barrier (HFB)

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
6. ## Hydraulic characteristic in Horizontal Flow Barrier (HFB)

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
7. ## Modflow multi layer conceptual model: slope

I've been confused by 2D and 3D Grid. I'm now able to insert the Barrier. That's ok. Thank you.
8. ## Modflow multi layer conceptual model: slope

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.
9. ## Modflow multi layer conceptual model: slope

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
10. ## MODFLOW multi layer: how to change layer properties by polygon coverage

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
11. ## Coverage layers assignment in Map to MODFLOW

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
12. ## Variable grid size: how to export cells size (width and lenght)?

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".
13. ## Variable grid size: how to export cells size (width and lenght)?

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
14. ## Contouring color ramp: no color or transparent color fill?

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
15. ## GMS 9.2 User Profile folder size

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
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