Porosity and permeability

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Porosityand permeability

Permeabilityand porosity are the prime properties that facilitate in determiningthe capacity of a sediment or rock substance to transmit and storewater. The two properties are usually intrinsically different.in ourexperiment we determined porosity which is characterized by thevolume of the available open sizes or the available pores that arethere between the solid mineral components which have made up theunconsolidated sediment or the rock( Fitts, C. R. (2013). This isexpressed as a percentage.


Whenprecipitation is contacted with a mixture of sand and gravel it haslow permeability than when there is no sand.


Theexperiment used the following materials for it to be successful.Water was used there were approximate two cups of sand with600ml.gravel was 600ml, this was the gravel of what would go in thefish tank. A stop watch was necessary and a calculator 2 cup capacitywas necessary for measuring the cup with ml calibrations foodcoloring was optional not a must. This is because it is much easierfor the water to be viewed in the cup and the sediments since thewater is brightly colored. There were also 3 plastic cups for puttingthe sediments, cups which on does not mind putting the sediments.They were three of the same size. A camera was necessary in order totake the digital images of the lab set up.


400mlof sand was measured and filed in one of the plastic cups.400ml ofgravel was filled in the second plastic cup. The remaining 200ml cupof sand and 200 ml of the cup gravel. They were mixed together andput in the third cup that was present. All the different three cupswere used to stand for different types of aquifers .

Thecup with gravel was taken and a known volume of distilled water .wehad to figure out the exact amount of water to be used when pouringinto the cup. Before starting the experiment (pouring water into thecups) there was great need to make two measurements. The stop watchwas used in order to the time taken in seconds to know the time takenfrom the moment of pouring water into the cups to the time taken forthe water to reach the bottom of 3the cylinder, when it reaches thestop watch was stopped in order to note down the time taken. Thewater was poured slowly and the stop watch started. The water waspoured slowly until it reached the surface of the sediments. Thesediments had to be dried to start over again. The time elapsed wasrecorded in a table. The flow velocity was calculated the water thathad been added to the sediments was determined. The porosity was alsocalculated.


Aquifer type


Sediment size

Starting volume of water(ml)

Ending volume of water(ml)

Volume of pore space (ml)

Porosity(%) pore space /total volume *100

Gravel only

1 cup

2 cups



Gravel and sand

1 cup

2 cups



Sand only

1 cup

2 cups



Aquifer Type

Flow Velocity

Sediments size

Height of sediments


Elapsed time


Flow velocity


Gravel only




Sand and gravel




Sand only


2 sec



Thepurpose of the experiment was to identify the best type of soil formaking an aquifer. The sizes of the soil particles greatly affectedthe porosity and flow velocity (Drever, J. I. 2005). Sand has biggerparticles which created larger spaces allowing great flow velocityand thus low porosity. The experiment had errors when taking readingson time with the stop watch since it was faulty.


Theexperiment was a great success as we were able to achieve ourobjectives in the determination of flow velocity and porosity.


Drever,J. I. (2005). Surfaceand ground water, weathering, and soils.Amsterdam: Elsevier.

Fitts,C. R. (2013). Groundwaterscience.Oxford: Academic Press.