Tool T03 · Contamination Plume
Click to drop a contaminant.
Each click releases 400 tracer particles at a point. Groundwater flows (blue arrows), and the contaminant moves with it — spreading through dispersion as it goes. Press play to watch it migrate.
0 sources · 0.0 yr elapsed
Click anywhere on the canvas to drop a contaminant
40 ft/yr
Memphis Sand: ~20–60 ft/yr
0°
0° = flow to the right (east→west)
10 ft
Spreading along flow direction
2 ft
Spreading perpendicular to flow
The math
Each particle moves as advection + random walk. At each step: position += velocity·dt + N(0, √(2·α·v·dt)). The population of particles approximates a Gaussian plume — the solution to the advection-dispersion equation with an instantaneous point source.
Dispersivity (α) is a scale-dependent property. Field studies show α grows roughly with the distance traveled — which is why plume predictions become less precise as they extend.
Data:USGS Groundwater Notes·Fetter (1999)·CAESER