ABEN 3412 (Laboratory)
Irrigation and Drainage Engineering
LABORATORY EXERCISE 3 – DETERMINATION OF SOIL POROSITY AND PERMEABILITY
I. INTRODUCTION:
Determination of porosity and permeability of soil is essential for understanding its water-
holding capacity and how easily water can flow through it. Porosity can be calculated by
measuring the volume of void spaces in the soil compared to the total volume, while
permeability describes how easily water can flow through those spaces underground.
Understanding both porosity and permeability is crucial for assessing water movement in
the ground and it is typically determined through laboratory tests that measure the rate at
which water can flow through the soil under certain conditions. And also, by determining the
porosity and permeability of soil, one can better understand its water storage and
transmission capabilities, which are important factors in various engineering and
environmental applications.
In this laboratory exercise, students are divided into six (6) groups and are distributed to
different areas within Central Luzon State University and determine the porosity and
permeability of different soil types in each designated area.
II. OBJECTIVE:
At the end of the exercise, the student must be able to determine soil porosity and
permeability.
III. MATERIALS & EQUIPMENT
● 2 paper cups (1 with a hole and 1 without a hole in the bottom)
● Graduated cylinder
● Jar or beaker or container
● Soil samples (taken from the area assigned to each group)
● Marker/pen
● Spoon/scraper
● Stopwatch or other timing device
IV. PROCEDURE
A. Determining Soil Porosity
1. Pour 100 mL of water into the cup and mark the 100 mL point. Record the total volume
(100 mL) of water on the data sheet. Remove the water.
2. Fill the cup with the soil sample up to the 100 mL mark in the cup.
3. Using the graduated cylinder, slowly and carefully pour water into the cup until the water
reaches the top of the sample. Record the volume of remaining water in the graduated
cylinder on the data sheet.
4. Subtract the volume remaining from the total volume. This is the amount of water added
to the sample. The volume of water added to the soil sample is the pore space.
5. To determine the porosity of the sample, divide the pore space volume by the total
volume and multiply the result by 100.
ABEN 3412 (Laboratory)
Irrigation and Drainage Engineering
6. Porosity or % pore space = (pore space / total volume) x 100.
B. Determining Soil Permeability
1. Hold the empty cup with a hole over a jar or an empty cup/container. Carefully pour the
sample into the cup with the hole (the hole will allow the water to drain into the jar).
2. Pour 100 mL of water into the cup with the sample. Record the time from pouring until
the water starts to drain (in seconds) out of the soil sample (through the hole).
C. Repeat Parts A and B for other soil samples (soil types)
V. RESULTS AND DISCUSSION:
DOCUMENTATION:
A. (Determining Soil Porosity)
SMALL SHOVEL 2 CUPS WITH THE LABEL OF SOIL SAMPLES FROM THE AREA
(SPOON) SOIL POROSITY (without hole) AND WE ASSIGNED (UCHS)
POROSITY (with hole)
GRADUATED
WATER
CYLINDER
MATERIALS NEEDED FOR THIS EXPERIMENT
ABEN 3412 (Laboratory)
Irrigation and Drainage Engineering
Slowly pour the water into the graduated cylinder until it reaches a 100 ml
Carefully pour the 100 ml water into the cup and mark the 100 ml point using a marker,
then remove the water and make a small hole in the cup using a sharp object
Pour the soil sample into the cup gradually, continue adding soil until the soil
reaches the 100 mL mark on the cup
Slowly pour the water from the graduated cylinder into the cup containing the soil sample, continue
pouring the water carefully until the water level reaches the top of the soil sample and once the water
level stabilizes at the top of the soil sample, stop pouring water
RECORD THE DATA OF REMAINING WATER IN THE GRADUATED CYLINDER ON THE DATA SHEET
ABEN 3412 (Laboratory)
Irrigation and Drainage Engineering
B. (Determining Soil Permeability)
handle the cup with care to avoid spillage and ensure that the water drains into
the 2nd cup or jar and pour 100 mL of water into the cup containing the soil sample
WRITE DOWN THE AMOUNT OF TIME FROM WHEN THE WATER BEGAN TO POUR UNTIL
THE WATER BEGAN TO DRAIN FROM THE SOIL SAMPLE THROUGH THE HOLE.
SOIL TYPE: CLAY
TOTAL VOLUME: 100 ml
VOLUME REMAINING IN CYLINDER: 59 ml
PORE SPACES: (100 ml - 59 ml) = 41 ml
POROSITY (%pore space): (41 ml / 100 ml) (100) = 41 %
PERMEABILITY (time from pouring to draining of water in seconds): 64 seconds
The laboratory exercise involves studying soil porosity and permeability using specific
materials and equipment. By filling the cup with soil sample up to the 100 mL mark and measuring
the water added to the sample, you can determine the soil porosity. Additionally, by pouring water
into the cup with a hole and timing how long it takes for the water to drain out, you can assess
soil permeability. These experiments help in understanding the characteristics of the soil and its
ability to retain and transmit water.
This laboratory exercise was conducted on February 7, 2024, and soil samples were taken
at UCHS, CLSU and identified the soil type as clay soil. Understanding the soil composition can
be crucial for various purposes especially in agriculture, clay soil is highly porous, it has very low
permeability, making it difficult for water to flow through and causing water to become trapped
within it. The experiment demonstrated a slow and steady drainage of water from the soil through
the hole, taking over 64 seconds for the water to fully seep into the hole.
The results of the determination of soil porosity and permeability can provide valuable
insights into the water-holding capacity and flow characteristics of the soil sample. By recording
the time, it takes for water to start draining through the soil sample, we can calculate the
ABEN 3412 (Laboratory)
Irrigation and Drainage Engineering
permeability of the soil. Additionally, by measuring the volume of void spaces in the soil compared
to the total volume, we can determine the porosity of the soil.
VI. CONCLUSION/RECOMMENDATION:
In conclusion, this laboratory exercise focused on determining soil porosity and soil
permeability using methods such as the Pycnometer Method for porosity estimation, it is a widely
used for laboratory technique to measure the volume of pores inside a soil sample. The idea
behind this technique is to measure the amount of water that is displaced by using a soil sample
to move water out of a container with a specified capacity. and the Falling Head Permeameter
Method and The Constant Head Method for soil permeability measurement which can measure
the rate of water flow through a soil sample. We also observed how factors including Soil Texture
and Soil Structure affects the measurement of the soil porosity and soil permeability. On the other
hand, during the conduct of this exercise, it is recommended to use transparent and the same
sizes of cups to allow smooth and easy conduct of the exercise and ensure the consistency of
results. Lastly, to ensure the reliability of the measurement, it is recommended to perform multiple
measurements.
VII. REFERENCES:
Department of Energy, E. and C. A. (2019, May 6). Understanding porosity and
permeability - Resources Victoria. Earth Resources.
https://resources.vic.gov.au/projects/victorian-gas-program/onshore-
conventional-gas/porosity-permeability
Table 1. Soil porosity and permeability
Group Soil Total Volume Pore Porosity Permeability (time from
Type Volume Remaining Space (% pore pouring to
(mL) in (mL) space) draining of water in
Cylinder seconds)
(mL)
ABEN 3412 (Laboratory)
Irrigation and Drainage Engineering
1 Clayey 100 72 28 28 51.75
Silt
2 100 53 47 47 4.16
3 CLAY 100 52 48 48 23.89
4 100
5 CLAY 100 59 41 41 64
6 100
