What is it?
MODFLOW is the modular hydrologic model developed by the USGS and widely considered an international standard for simulating and predicting groundwater conditions and groundwater/surface-water interactions. IGW-NET provides the user with this tool to run and visualize existing MODFLOW groundwater models. Models are loaded and displayed using the python module FloPy developed by the USGS.How to use it?
1) Start by uploading a zipfile containing MODFLOW model input files
- Model namefile should have extension ".nam"
- Model projections can be defined by including a .prj file in the model zipfile.
- Model displays (MF2000 and MF2005) can be projected or rotated after loading the model, or by placing the following line in the second line of the namefile
"#xll:x0; yll:y0; rotation:rotation; units:prj units; lenuni:model unit flag"
(where x0,y0 are the coordinates of the lower left corner of the grid;
rotation is the counter-clockwise rotation of the grid(in degrees);
prj units are the units for the grid [must be "feet" or "meters"];
model unit flag units flag from the discretization package)
2) View model stress periods layers and Boundary Conditions packages
Visualization supported for packages
- CHD, DRN, RIV, WEL, LAK,
- GHB, BAS6(IBOUND,CHD), RCH, EVT
3) Run Model
Select display and draw options while model is running
check option to "Save all heads and budgets" to modify Output Control (OC) package to save heads and cell-by-cell budgets for each timestep.
4) View Results
View model results
View model water budgets
Plot model cross sections
Plot model hydrograph (for transient models)
Plot model results vs calibration data
5) Download Results
Select and download MODFLOW model results
Model exports as well as files with extensions 'out','obs','csv','bin','txt','list', and 'lst'
Model Network Tools
After Models are loaded they can also be shared or saved along with associated images and files via the Model Network 'Publish Model'. MODFLOW models that the user has already published to the Model Network can be deleted, edited, or loaded by clicking the 'View/Edit Your Published Models'Tool Logfile
Internal errors from the tool may be checked by inspecting the tool log file. This can be found on the side bar:Analysis Tools > Analysis > View Run-time Msg > Select Msg File 'ZipMF Run-time Log File'
Supported Models
IGW-NET support is provided for the following:MODFLOW Versions
- MODFLOW-6 (if a simulation contains more than one model, only the first model is visualized)
- MODFLOW-2005
- MODFLOW-NWT
- MODFLOW-2000
MODFLOW Packages
- All packages supported by FloPy 3.3.1
- Visualization supported for packages
CHD, DRN, RIV, WEL, LAK,
GHB, BAS6(IBOUND,CHD), RCH, EVT
Unsupported Models
At this time IGW-NET does not provide complete support for the following:- MODFLOW-USG Models
- True unstructured grids
- Plotting for unsimulated layers
Guidence for model preparation
For best results using this tool check that:- All input files specified in the namefile (.nam) are present in the uploaded zipfile. Unless using the "Save all heads and budgets" feature:
- Head and cell-by-cell fluxes are saved for at least 1 model timestep (specified with 'save head' and 'save budget' in the output control, 'OC', file)
- MODFLOW 6 simulations specify to 'save flows' and 'save specific discharge' in the node property flow, 'NPF', file.