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>> In this third, and final installment, we will be looking at recharge
and surface water interaction using a physical model.
For this demonstration we will pour blue dye into the model, which represents precipitation
as it drips onto the land surface.
Once the blue water infiltrates the land surface
and enters the aquifer, it is considered recharge.
Watch carefully where the blue water goes.
On the right, you can see the dye soaking through the surface
and flowing deep into the ground.
It also moves horizontally with the flow of water.
Same in this area.
The blue dye can be seen moving deeper and to the left where the head is lower.
Let's rewatch this at a faster speed so that you can see the dye move more quickly.
Notice how the recharge shows up in the confined and carce [assumed spelling] aquifers as well.
If there is any contamination spread over the land surface such as from fertilizers
or pesticides the precipitation would pick it up and follow the same path
as the blue dye into our aquifers.
This is called non-point source pollution.
For point source pollution, contaminants are concentrated in a smaller area
such as a septic tank, underground storage tank, or an oil spill.
Let's see where the dye goes if these tanks have a leak.
Not only does the contamination flow ground water flow, it can easily discharge
into nearby lakes and rivers too.
For both point source and non-point source pollution, some dye remains in the ground just
like actual contaminants leaving behind a residue.
Cleaning up this residue can be costly and, in most cases, it can never be completely cleaned.
Be on the lookout for potential pollution and do your best to prevent groundwater contamination.
Thanks for joining me.
The next time you're out scoping the Texas heat in a cool spring,
think about how that water got to you.
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