Rainfall and recharge
Compare clay-rich, sandy and gravel aquifers. Explore how infiltration, land cover and seasonal plant water use affect the amount of rain reaching groundwater.
Dig Earth Studio / Interactive Earth Science
Dig Earth Studio LabGroundwater
Lab.
A free interactive groundwater simulation for students and teachers. Explore an aquifer below the surface, change rainfall and pumping, watch the water table rise or fall, and investigate groundwater exchange with a river or lake over one simulated year.
Interactive model · Version 1.5 · Classroom-friendly
02 / See below the surface
A window into the aquifer
Winter · January · Year 1
Rain 105 mm · Evapotranspiration 8 mm
On a small screen, swipe the timeline to see all 12 months.
Winter: lower plant water use generally favours recharge. Run a year to unlock monthly results.
Water table
Sandy aquifer
Clay layer
Flow direction (can reverse)
On a small screen, swipe the cross-section sideways to explore.
Stored water equivalent
Water reaching the aquifer
Groundwater entering river / month
Water-equivalent storage · variable level
Sufficient groundwater
03 / Read the results
Water storage through time
Stored groundwaterLake storageAdjust conditions and press Play.
Monthly groundwater budget · Before January
Recharge entering aquiferNot started
Groundwater pumpedNot started
To river or lake (+), from river or lake (−)Not started
Regional groundwater drainageNot started
Change in groundwater storageNot started
Lake overflow leaving systemNot started
Run the experiment to see the water inputs and outputs for each month. These are conceptual equivalent water depths.
04 / Think like a hydrogeologist
What's happening?
Can an aquifer recover when pumping slows down?
Run the simulation and compare recharge with the water being pumped out and discharged to the river.
Investigation: Run January through December, then select different months on the timeline. Compare the highest and lowest water storage, recharge, and whether the river or lake is gaining or losing water. Press Replay to watch the same results again.
Classroom challenge · Water manager
Not started
Can your town survive a drought without draining its groundwater?
Your mission: A town depends on an underground aquifer for its water. Rainfall is unusually low this year. You are the water manager. Choose how much water to pump each month so the town gets enough water, but the aquifer never becomes dangerously depleted in this model.
The dilemma: pump too little and the town does not get enough water. Pump too much and groundwater storage becomes too low. Can you find a balance?
Goal 1 · Supply the town
60 mm or more
Total groundwater actually pumped over the entire 12-month year
Goal 2 · Protect the aquifer
80 mm or more
Groundwater storage remaining at the end of every month, including the lowest month
These are illustrative classroom targets, not real-world water-management limits. All attempts start at 150 mm groundwater storage so results are comparable. The mm values represent an equivalent water depth over the model area, not the physical depth of a well.
1 · Accept the mission
2 · Set your pumping rate
3 · Predict, then press Play
4 · Inspect your year-end results
Rainfall will be fixed at a drought average of 15 mm per month. You control only the pumping rate. After 12 months, the lab checks whether both goals were achieved.
Challenge results
Total water supplied to town 0 mm
Lowest groundwater storage 0 mm
Reflect: if the town repeated this pumping strategy for several years, would its groundwater supply remain secure? Compare the end of the year with the starting storage.
Your task is to find a rate that meets the water-supply goal and keeps groundwater above the safety level in every month.
Free groundwater activity · For students and teachers
Explore how groundwater moves through an aquifer
Groundwater is water stored in the pores and fractures of soil and rock. The water table marks the upper surface of the saturated zone in an unconfined aquifer. In this interactive aquifer simulator, students can see how that level responds to rainfall, recharge, groundwater pumping and nearby surface water.
Wells and the water table
Change groundwater extraction and starting storage. Watch pumping draw down the water table and investigate why groundwater may recover when demand decreases.
Rivers, lakes and groundwater
Switch between a river and a lake to see how water can move in either direction. Compare gaining and losing surface-water conditions and inspect the monthly budget.
How to use this groundwater experiment in class
- Make a prediction. Choose one variable, such as rainfall, pumping, aquifer material or starting water storage, and predict how the water table will change.
- Run a full year. Select Normal or Slow and press Play. The model stops automatically after December.
- Inspect the evidence. Select individual months to compare recharge, pumping, river or lake exchange and changes in stored groundwater.
- Compare fairly. Reset and change one factor at a time. Keep the starting groundwater level the same between runs.
- Try the drought challenge. Find a pumping rate that meets a town's water-supply target without dropping below the model's groundwater reserve.
Frequently asked questions
- Is this groundwater simulation free?
- Yes. Groundwater Lab runs in a web browser without a purchase or account.
- What is the difference between aquifer storage and water-table depth?
- The slider and chart use millimetres of water-equivalent storage, not a measured depth below ground. The cross-section illustrates how the water table may respond; it is not to scale.
- Is this a model of a real aquifer?
- No. This is a simplified teaching model, not a site-specific groundwater prediction. Its purpose is to explore relationships and practise interpreting a water budget.
- Can groundwater flow into a river or out of it?
- Both are possible. In the model, the direction of groundwater–surface-water exchange depends on the relative water levels in the aquifer and the river or lake.
Related experiment: Try Flood Resilience Lab to investigate how infiltration and land cover influence runoff and flood peaks, or explore all free Earth science labs.
About this model: A conceptual teaching model of a connected unconfined aquifer and either a river or lake. The sign of surface-water exchange comes from a simplified hydraulic-head difference: groundwater can discharge into surface water, or surface water can infiltrate toward groundwater. Positive exchange means surface water gains groundwater; negative exchange means surface water supplies groundwater. Each month's displayed exchange and directional arrows reflect that month's recorded model exchange. The river is assigned a maintained stage and supply from upstream, while the lake has a separate monthly budget for direct rain, approximate open-water evaporation, surface inflow, outlet flow and groundwater exchange. The lake displays the net exchange, not simultaneous inflow and outflow through different shores. Lake storage is shown as an equivalent water depth, not a measured lake depth. Surplus groundwater at the 300 mm storage cap is counted as regional drainage leaving through a separate aquifer outlet, while surplus lake water at 240 mm is counted as spillway overflow instead of being discarded. Water levels, streamlines, head gradients and permeability are qualitative schematic approximations. Disconnected streambeds, full three-dimensional flows, travel times and real site conditions are not simulated. The starting water table follows the selected groundwater storage and can strongly influence the first simulated year; keep the starting level consistent when comparing experiments. The seasons represent an illustrative Northern Hemisphere temperate cycle, not observed weather; all diagrams are not to scale.