Non-point source pollution
1. Put the aquarium stones in the plastic container. Slope the stones to form a lake at one end of the model.
2. Add a layer of sand over the stones. (Sand is used instead of soil to maintain water clarity.) Pat down the sand to minimise erosion.
3. Sprinkle a few spoonfuls of coloured sugar or jelly crystals onto the sand to represent the substance being applied to the land, for example, lawn fertiliser.
4. Hold the cup over the model. Pour some water into the cup to simulate rain. Move the cup around so it rains over the entire model. Refill the cup as needed and continue to rain on the model until a small lake forms.
5. Look at what happens as the rain comes in contact with the coloured sugar. It dissolves the substance and takes it down through the soil into the aquifer. If the rain is heavy enough, some of the sugar runs off into the surface water. Either way, the contaminant ends up in the ground and surface water.
Point sources of pollution
6. Set up the aquifer model using stones and sand. The sand layer at the top of the model needs to be fairly thick.
7. Make a small hole and add some coloured sugar. Cover the sugar with sand to represent an old landfill.
8. Hold the cup over the model. Pour some water into the cup to simulate rain. Move the cup around so that it rains over the entire model. Refill the cup as needed and continue to rain on the model until a small lake forms.
9. Nothing may appear to happen at first. It takes time for the water to dissolve the contaminants in the landfill, but eventually the aquifer and the lake will turn the colour of the sugar. New landfill sites are built to reduce groundwater pollution. Their design includes a confining layer to prevent polluted water from escaping. The water is often collected and pumped to a wastewater treatment plant.