💧 IGW-NET · Quick Tutorial 1 of 31

Tutorial 1: 2D Steady Flow Modeling

Build a steady-state 2D groundwater flow model: set up boundary conditions, hydraulic conductivity, recharge, and wells, then solve and visualize head and flow.

IGW-NET Tutorial 1 Prereq: MAGNET4WATER account 4 sections

This tutorial covers

  1. Model with Data Center Inputs
  2. Model with Effective Value Inputs
  3. Using the MODFLOW Solver
  4. What's Next

1Model with Data Center Inputs

IGW-NET interface showing model domain selection on a georeferenced map with Data Center toolbar
IGW-NET interface — zoom to your area of interest and draw the model domain

Step 1 — Draw the Model Domain

Zoom to the area of interest on the map. Click the Draw Domain button Draw Domain tool and delineate your regional model domain.

Step 2 — Assign Parameters from the Data Center

Click Server Data button Assign button to assign default parameters from the Server for the model domain. The Data Center provides spatially-explicit recharge, hydraulic conductivity, aquifer bottom elevation, and other properties — pre-processed and ready to use.

Step 3 — Submit for Simulation

Submit the job for simulation. The IGW solver runs in real time — you'll see results streaming as the equations solve.

Step 4 — Visualize Flow Patterns

View flow patterns in plan view and cross-section view. Click Cross-section button the X-section tool to draw a new cross-section anywhere across your domain. Heads, flow vectors, and water table are displayed simultaneously.

Step 5 — Save or Publish

Click Publish button Save button Save options to publish the model to the Observatory or save it for future use.

Complete 2D steady-state model with plan view showing head contours, flow vectors, and cross-section below showing water table and aquifer layers
Figure A1–A3: Complete model results — plan view with head contours and flow vectors (top), cross-section showing water table profile and aquifer geometry (bottom)
Data Center parameter assignment showing spatially variable recharge and conductivity fields
Data Center parameters — spatially variable inputs assigned automatically from the Global Base Model

2Model with Effective Value Inputs

IGW-NET effective value input dialog showing single K, recharge, and aquifer bottom values
Effective value mode — single representative values for sites without detailed Data Center coverage

Step 1 — Draw the Model Domain

Click Draw Domain button to delineate the regional model domain, same as Part A.

Step 2 — Assign Effective Values

Click Assign button Effective values button to assign input parameters as single, effective values. Use representative values for hydraulic conductivity, recharge, and aquifer geometry when detailed spatial data is not yet available.

Step 3 — Submit for Simulation

Submit the job for simulation.

Step 4 — Visualize and Inspect

View flow patterns in plan and cross-section view. Click Cross-section button Additional tools to examine model inputs and results at any node location.

Step 5 — Save or Publish

Click Save button Save options to publish or save the model for future use.

Effective value model results showing head distribution and flow vectors in plan view
Figure B1–B2: Effective value model setup and parameter assignment
Effective value model results with cross-section and node inspection showing head, conductivity, and flux values
Figure B3: Model results with node inspection — click anywhere to see computed head, conductivity, and flux values

3Using the MODFLOW Solver

IGW-NET offers two solver engines: the default IGW engine (real-time streaming visualization) and the MODFLOW engine (USGS standard, regulatory-accepted). Same conceptual model, same grid — different solver. Switch with a few clicks.

Step 1 — Set Up the Model

Follow Steps 1–2 from Part A or Part B to select an area and assign input parameters for either type of 2D flow model.

Step 2 — Choose the MODFLOW Solver

Click Solver selection button MODFLOW option Assign button to switch to the MODFLOW solver. Then click Additional settings Confirm to confirm settings.

Step 3 — Submit for Simulation

Submit the job for simulation. MODFLOW solves the same equations using the USGS-standard numerical scheme.

Step 4 — Visualize Results

View flow patterns in plan or cross-section view using Visualization button the same visualization tools as Parts A and B.

Step 5 — Save or Publish

Save Save Save button or publish Publish the model.

MODFLOW solver results showing head distribution and flow vectors, comparable to IGW solver results
Figure C1: MODFLOW solver results — same model, same domain, USGS-standard solver. Compare with IGW results from Parts A and B.

4What's Next

Now that you've built your first model, continue the learning path:

Tutorial 2: Nested Models — insert a high-resolution model inside your regional model
Tutorial 3: Particle Tracking — trace flow paths and delineate wellhead protection areas
Tutorial 4: Water Balance — analyze where water comes from and where it goes