OBSERVATION / PROBLEM STATEMENT: Many of man's activities can negatively impact the

environment. One such activity is deforestation. While this may be necessary for housing and
agriculture, it can cause effects as soil erosion and make water conservation difficult.

HYPOTHESIS: Deforestation decreases the amount of vegetation cover, which will increase the amount
of soil erosion and water runoff because the vegetation helps to stabilize the soil with its root systems
and absorbs water; thereby reducing the speed and volume of water runoff.

AIM: To simulate the effects of deforestation and soil erosion on water conservation.

APPARATUS AND MATERIALS: Three large bottles (at minimum 2 liters in volume), Soil, Grass or Plant
cover (dead leaves), Watering can, Wooden blocks, Three small bottles, Water, Ruler, Scale, Stopwatch,
Scissors, String

PROCEDURE:
1. Bisect the three large bottles by making a horizontal cut about 1 cm above the neck of the bottle.
2. Fill the halved bottles with soil until you cannot add any more or else the mouth of the bottle is
obstructed.
3. Have 1 bottle fill with only soil, another covered in moderate amount of plant coverage over the
surface to simulate forest cover and have the last one covered with above average plant cover. Make
sure the plants have roots that hold the soil.
4. Position the bottles on a slight slope using wooden blocks.
5. Halve the three water bottles from side to side, 5 cm above the base.
6. Pierce a small hole on both sides of the three bottles, enough so in diameter that a string can be
knotted around both sides.
7. Hang the small bottles around the necks of the larger bottles so that any water exiting the mouth can
easily fall into the smaller bottles.
8. Simulate rainfall by pouring a measured amount of water (e.g. 500 ml) either by using a watering can
or puncturing holes in a water bottle.
9. Observe the movement of soil and water runoff from each of the large bottle as it fills the smaller
bottles.
10. After a minute of water application, measure the amount of soil that has eroded from each bottle (by
visually inspecting the water clarity or using a scale to compare the weights of the soil collected).
11. Record the data obtained
12. Repeat the experiment 2 more times as to ensure consistent results.

VARIABLES:
Manipulated – The amount of vegetation cover between the three large bottles.
Responding – The amount of displaced soil or sediments that is carried over into the smaller bottles.
Control – The amount of water applied on the larger bottles.

EXPERIMENTAL CONTROL:
The control in this experiment would be the half bottle of soil that is neither fully deforested nor fully
covered with plant, but instead contains light coverage that is to simulate a standard condition. This
control helps determine the baseline rate of soil erosion and water runoff under normal conditions
without significant deforestation or dense plant cover. By comparing results from the deforested bottle,
the forested bottle, and the control bottle, we can more accurately observe the differences in the
amount of soil erosion and water runoff that can be attributed to the presence or absence of dense
vegetation, rather than other factors like soil type or slope angle.

EXPECTED RESULTS:
The expected results from the experiment simulating the effects of deforestation and soil erosion, and
how it makes water conservation difficult are as observed and noted. Firstly, the forested bottle will have
minimal soil erosion, the highest water retention for water conservation, and clear runoff whereas the
deforested area will show significant soil erosion, the lowest water retention for water conservation, and
a very murky runoff due to soil particles being washed away. The bottle with light vegetation coverage
will have some amount of soil erosion though neither as much as the deforested bottle or as little as the
forested bottle, the water retention will also lay in between the two extremes and water runoff will only
be slightly murky.

EXPLANATION OF EXPECTATIONS:
The roots of the plants help bind the soil particles, reducing the likelihood of them being washed away
during rainfall. Additionally, the leaves and stems of the plants slow down the movement of water,
allowing it to infiltrate the soil rather than running off. Without it the soil becomes loose, and more
vulnerable to erosion. When water is in this scenario applied, it washes away the loose soil easily,
leading to a noticeable amount of it being displaced. This is the reason why the expected results of the
experiment have the bottles with plant coverage will experience much less soil erosion and water runoff
compared to the bottle without plant coverage. Of course, the greater the density of vegetation, the
more magnified the effects are.

TREATMENT OF RESULTS:

PRECAUTIONS
1. Avoid overwatering and apply a reasonable amount of water to avoid flooding the experiment
and causing excessive runoff in all the bottles.
2. Ensure the station/stand is sufficiently stable enough to perform the experiment.

ASSUMPTIONS
1. The soil composition is uniform; same type and composition.
2. Environmental factors such as temperature and wind remain constant throughout the
experiment.

SOURCES OF ERROR
1. Uneven water distribution of the set-up which will lead to inaccurate soil displacement.
2. Human error in either taking measurements for the experiment or the viewing of water clarity as
it differs between people.

LIMITATIONS
1. A simplified vegetation representation compared to real forests and ecosystems.
2. A uniform soil type, unlike real natural environments with varying soil types (e.g. clay, silt, peat,
etc.).
3. A lack of environmental factors like temperature, wind speed, etc.
(Liable to additions and removals when I am in school)