|
Understanding Run-off
Water runoff occurs when water, snow melt or irrigation runs over land and seeps into the ground
or flows to local body of water. In the process of water runoff, water picks up pollutants,
nutrients, and sediments and carries them to the river, lakes, oceans and ground waters.
Understanding water runoff is essential to understanding a healthy environment as well as
water pollution.
Procedure
1. Potting Soil
- Get a sieve set from your teacher.
- Fill the top sieve with 2.5 inches of potting soil.
- Put 5 drops of food coloring on top of the soil and another 5 drops in water.
- Obtain 250 ml of water using a graduated cylinder or beaker and pour the water to the spray bottle.
- Spray all the water evenly on top of the potting soil. Make sure that the nozzle is spraying
and not jet streaming.
- Allow the water to filter for 2 minutes.
- Measure the amount of water collected in the bottom of the sieve.
- Write your observations on the data table below.
| Potting Soil |
Putting water using a
spray bottle |
Dumping water using a
beaker |
| How much water (in milliliters) was recovered in the bottom of the sieve? |
|
|
| What is the color of the water collected in the bottom sieve? |
|
|
- Clean the sieve before doing the next experiment.
- Follow steps 1a-1c with a new sample of potting soil.
- Instead of using the spray bottle, dump all the 250 ml of water directly on top of the potting soil.
- Then follow steps 1e-1h.
2. Gravel
- Replace potting soil in Part 1 with gravel. Then follow steps 1a-1l.
| Gravel |
Putting water using a
spray bottle |
Dumping water using a
beaker |
| How much water (in milliliters) was recovered in the bottom of the sieve? |
|
|
| What is the color of the water collected in the bottom sieve? |
|
|
3. Tiles or brick
- Replace gravel in Part 2 with tiles or brick. Then follow steps 1a-1l.
| Tiles or brick |
Putting water using a
spray bottle |
Dumping water using a
beaker |
| How much water (in milliliters) was recovered in the bottom of the sieve? |
|
|
| What is the color of the water collected in the bottom sieve? |
|
|
Analysis Questions
1. How much water is absorbed by the following materials?
| Materials |
How much water is absorbed after spraying the water? |
How much water is absorbed after dumping the water? |
| Potting Soil |
|
|
| Gravel |
|
|
| Tiles or Brick |
|
|
2. Which material can absorb the most and which one absorbs the least?
| 3. |
Does the amount of water recovered depend on how the water was introduced?
(Pouring vs. sprinkling)? Explain. |
| 4. |
How do different types of ground cover (soil, gravel, and tiles) affect the
color of the recovered water?. |
| 5. |
What do you think is the purpose of adding food coloring to the samples or what is it representing? |
| 6. |
Do you have any other observations? |
Assessment Question
1. Explain how impervious surfaces can potentially increase water pollution runoff.
Alternative Activity
"Salt Marsh in a Pan" pdf doc (developed by the NJ Marine Sciences Consortium) - Students create a model of a salt marsh to discover the impact of pollution and human activities on water-based habitats including bays and the ocean. Model may also be used to demonstrate salt marsh functions, non-point source pollution and watershed concepts.
|
