Each applet in the list has three buttons next to its name:
— opens the model in a small popup window.
↗ — opens the model in a new browser tab.
↓ — downloads a standalone HTML file so you can run the model offline.
Once a model is open, look inside it for UI Tutorial and Solution Tutorial buttons — the UI tutorial walks you through the controls, and the solution tutorial covers the underlying theory and equations.
For a quick overview of every model with direct tutorial links, click the Applet Guide button on the home page.
Applet Guide
Short descriptions and tutorial links for each interactive model
Spherical Diffusion — Radial Diffusion into a Sphere
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Simulates radial diffusion of a solute into (or out of) a sphere using the Crank (1975) analytical solution. Plots concentration profiles C(r,t) at up to five snapshot times showing the diffusion front moving inward, and the fractional approach to equilibrium f(t) = Mt/M∞ showing how quickly the sphere reaches steady state. Governed by the radial diffusion equation with a constant surface concentration boundary condition.
Simulates 1D advective-dispersive transport of a reactive solute with equilibrium sorption (linear, Freundlich, or Langmuir isotherms) and first-order decay. Plots concentration vs. distance or vs. time. Based on the analytical solution of van Genuchten & Alves (1982).
Extends 1D transport to a two-site kinetic sorption model where sorption is split between fast-equilibrium and slow-kinetic sites. Includes separate first-order decay rates for liquid, kinetic-sorbed, and equilibrium-sorbed phases. Solver based on CXTFIT-1 (Toride et al., 1993).
Models a chain of up to four coupled solutes (S1 → S2 → S3 → S4) undergoing 1D transport with equilibrium linear sorption and first-order sequential decay. Each species has its own retardation factor and decay rate. Useful for studying contaminant daughter-product chains (e.g., chlorinated solvents).
2D Equilibrium Sorption with 1st Order Decay [Cleary-Ungs / Domenico]
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Computes a 2D steady-state contaminant plume from a continuous source in a uniform flow field using the Domenico (1987) or Cleary-Ungs analytical solution. Displays concentration contours in plan view (x-y) with optional horizontal and vertical cross-section profiles. Includes linear sorption and first-order decay.
3D Equilibrium Sorption with 1st Order Decay [Domenico]
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Extends the Domenico model to three dimensions (x, y, z) with a finite-height source zone. Displays concentration contours in plan view (x-y) and vertical cross-section (x-z). The additional z-dimension lets you evaluate vertical plume spreading and the role of source thickness on downgradient concentrations.
2D Steady Flow in Homogeneous Aquifers — Particle Tracking
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Computes 2D steady-state groundwater flow in a uniform aquifer with any combination of injection/extraction wells and a regional background gradient. Place particles by clicking the domain and track their paths forward in time. Includes head contour visualization, capture-zone analysis via boundary particles, and preset demo scenarios (doublets, single wells, regional flow).
Generation of Log Normal Spatially Correlated Random Fields
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Generates 2D spatially correlated log-normal random fields of hydraulic conductivity using the Fgen92 spectral simulation method (Robin & Schmidt, University of Waterloo, 1992). Specify grid dimensions, grid spacing, mean and variance of ln K, correlation lengths, and spectrum type (Gaussian or Exponential). Visualize the field with a color map, extract horizontal and vertical cross-sections, plot empirical vs. theoretical auto-covariance, and download the full log K field as a CSV.
Solves 2D steady-state groundwater flow using the finite element method on a rectangular domain with user-defined heterogeneous hydraulic conductivity zones. Computes the velocity field and tracks an ensemble of particles to visualize dispersion caused by aquifer heterogeneity. You can animate particle clouds and export spatial variance statistics to study macro-dispersion.
Non-Leaky (Theis) and Leaky (Hantush-Jacob) Aquifer Pumping Test
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This application implements the graphical curve-fitting method for pumping test analysis to estimate aquifer hydraulic parameters. The user can upload field data and manually adjust theoretical type curves to fit the data. The user should download the executable java application to run locally.
A numerical groundwater flow (MODFLOW) model runs remotely as a web application. The model simulates a 2D unconfined aquifer connected to a river. Users can interact with the model through a web browser to add pumping wells and make other changes. The user can study the impact of pumping on water table elevation and river discharge.
Developed by
A. J. Valocchi
(valocchi@illinois.edu), C. J. Werth (werth@utexas.edu),
J. J. Decker, G. Hammond, P. Zhou, M. Hafiz, M. G. Chen,
Devansh Agarwal (da30@illinois.edu)
Supported by Provost's Initiative on Teaching Advancement
(University of Illinois Educational Technologies Board),
Department of Civil and Environmental Engineering, National Science Foundation
