Geology

How to Calculate and Solve for Storativity of a unconfined aquifer | Aquifer Characteristics

Last Updated on April 6, 2024

The image above represents storativity of an unconfined aquifer. To calculate the storativity of an unconfined aquifer, three essential parameters are needed, and these parameters are Specific Yield (Sy), Aquifer Thickness (b) and Specific Storage (Ss).

The formula for calculating storativity of an unconfined aquifer:

S = Sy + bSs

Where:

S = Storativity of an Unconfined Aquifer
Sy = Specific Yield
b = Aquifer Thickness
Ss = Specific Storage

Let’s solve an example;
Find the storativity of an unconfined aquifer when the specific storage is 9, the aquifer thickness is 11 and the specific storage is 21.

This implies that;

Sy = Specific Yield = 9
b = Aquifer Thickness = 11
Ss = Specific Storage = 21

S = Sy + bSs
That is, S = 9 + (11)(21)
S = 9 + 231
S = 240

Therefore, the storativity of an unconfined aquifer is 240.

Read more: How to Calculate and Solve for Steady Flow in a unconfined aquifer | Flow lines

Calculating the Specific Yield when the Storativity of an Unconfined Aquifer, the Aquifer Thickness and the Specific Storage are Given

Sy = S – bSs

Where:

Sy = Specific Yield
S = Storativity of an Unconfined Aquifer
b = Aquifer Thickness
Ss = Specific Storage

Let’s solve an example;
Find the specific yield when the storativity of an unconfined aquifer is 42, the aquifer thickness is 10 and the specific storage is 3.

This implies that;

S = Storativity of an Unconfined Aquifer = 42
b = Aquifer Thickness = 10
Ss = Specific Storage = 3

Sy = S – bSs
That means, Sy = 42 – (10)(3)
Sy = 42 – 30
Sy = 12

Therefore. the specific yield is 12.

Read more: How to Calculate and Solve for Storativity of a Confined Aquifer | Aquifer Characteristics

Calculating the Aquifer Thickness when the Storativity of an Unconfined Aquifer, Specific Yield and the Specific Storage are Given

b = S – Sy / Ss

Where;

b = Aquifer Thickness
S = Storativity of an Unconfined Aquifer
Sy = Specific Yield
Ss = Specific Storage

Let’s solve an example;
Find the aquifer thickness when the storativity of an unconfined aquifer is 35, the specific yield is 14 and the specific storage is 7.

This implies that;

S = Storativity of an Unconfined Aquifer = 35
Sy = Specific Yield = 14
Ss = Specific Storage = 7

b = S – Sy / Ss
So, b = 35 – 14 / 7
b = 21 / 7
b = 3

Therefore, the aquifer thickness is 3.

Calculate the Specific Storage when the Storativity of an Unconfined Aquifer, Specific Yield, and the Specific Storage are Given

Ss = S – Sy / b

Where;

Ss = Specific Storage
S = Storativity of an Unconfined Aquifer
Sy = Specific Yield
b = Aquifer Thickness

Let’s solve an example;
Find the Specific storage when the storativity of an unconfined aquifer is 44, the specific yield is 20, and the aquifer thickness is 4.

This implies that;

S = Storativity of an Unconfined Aquifer = 44
Sy = Specific Yield = 20
b = Aquifer Thickness = 4

Ss = S – Sy / b
Then, Ss = 44 – 20 / 4
Ss = 24 / 4
Ss = 6

Therefore, the specific storage is 6.

How to Calculate Storativity of an Unconfined Aquifer Using Nickzom Calculator

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the storativity of an unconfined aquifer.

To get the answer and workings of the storativity of an unconfined aquifer using the Nickzom Calculator – The Calculator Encyclopedia. First, you need to obtain the app.

You can get this app via any of these means:

Web – https://www.nickzom.org/calculator-plus

To get access to the professional version via web, you need to register and subscribe for NGN 2,000 per annum to have utter access to all functionalities.
You can also try the demo version via https://www.nickzom.org/calculator

Android (Paid) – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator
Android (Free) – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator
Apple (Paid) – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8
Once, you have obtained the calculator encyclopedia app, proceed to the Calculator Map, then click on Geology under Add-on.

Now, Click on Aquifer Characteristics under Geology

Now, Click on Storativity of an Unconfined Aquifer under Aquifer Characteristics

How to Calculate and Solve for Storativity of a unconfined aquifer | Aquifer Characteristics

The screenshot below displays the page or activity to enter your values, to get the answer for the storativity of an unconfined aquifer according to the respective parameters which are the Specific Yield (Sy), Aquifer Thickness (b) and Specific Storage (Ss).

Now, enter the values appropriately and accordingly for the parameters as required by the Specific Yield (Sy) is 9, Aquifer Thickness (b) is 11 and Specific Storage (Ss) is 21.

How to Calculate and Solve for Storativity of a unconfined aquifer | Aquifer Characteristics

Finally, Click on Calculate

How to Calculate and Solve for Storativity of a unconfined aquifer | Aquifer Characteristics

As you can see from the screenshot above, Nickzom Calculator– The Calculator Encyclopedia solves for the storativity of an unconfined aquifer and presents the formula, workings and steps too.

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