How to Calculate and Solve for Peak Flow | Irrigation Water Requirement

October 2, 2020April 21, 2024 Loveth Idoko

Last Updated on April 21, 2024

The image above represents peak flow. To calculate peak flow, three essential parameters are needed and these parameters are Run off Co-efficient (C), Rain fall intensity (i) and Catchment Area (A).

The formula for calculating peak flow:

Q = CiA

Where:

Q = Peak Flow
C = Run off Co-efficient
i = Rain fall intensity
A = Catchment Area

Let’s solve an example;
Find the peak flow when the run off co-efficient is 12, the rain fall intensity is 16 and the catchment area is 18.

This implies that;

C = Run off Co-efficient = 12
i = Rain fall intensity = 16
A = Catchment Area = 18

That is, Q = CiA
Q = (12)(16)(18)
Q = 3456

Therefore, the peak flow is 3456.

Calculating the Run off Co-efficient when the Peak Flow, the Rain fall intensity and the Catchment Area are Given

C = ^Q / _iA

Where;

C = Run off Co-efficient
Q = Peak Flow
i = Rain fall intensity
A = Catchment Area

Let’s solve an example;
Find the run off co-efficient when the peak flow is 60, the rain fall intensity is 4 and the catchment area is 3.

This implies that;

Q = Peak Flow = 60
i = Rain fall intensity = 4
A = Catchment Area = 3

C = ^Q / _iA
Then, C = ⁶⁰ / _{4 x 3}
C = ⁶⁰ / ₁₂
C = 5

Therefore, the run off co-efficient is 5.

Calculating the Rain fall Intensity when the Peak Flow, the Run off Co-efficient and the Catchment Area are Given

i = ^Q / _CA

Where;

i = Rain fall intensity
Q = Peak Flow
C = Run off Co-efficient
A = Catchment Area

Let’s solve an example;
Find the rain fall intensity when the peak flow is 70, the run off co-efficient is 2 and the catchment area is 5.

This implies that;

Q = Peak Flow = 70
C = Run off Co-efficient = 2
A = Catchment Area = 5

i = ^Q / _CA
That is, i = ⁷⁰ / _{2 x 5}
i = ⁷⁰ / ₁₀
i = 7

Therefore, the rain fall intensity is 7.

Calculating the Catchment Area when the Peak Flow, the Run off Co-efficient and the Rain fall Intensity are Given

A = ^Q / _Ci

Where;

A = Catchment Area
Q = Peak Flow
C = Run off Co-efficient
i = Rain fall intensity

Let’s solve an example;
Find the catchment area when the peak flow is 90, the run off co-efficient is 10 and the rain fall intensity is 3.

This implies that;

Q = Peak Flow = 90
C = Run off Co-efficient = 10
i = Rain fall intensity = 3

A = ^Q / _Ci
So, A = ⁹⁰ / _{10 x 3}
A = ⁹⁰ / ₃₀
A = 3

Therefore, the catchment area is 3.

How to Calculate Peak Flow With Nickzom Calculator

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the peak flow.

To get the answer and workings of the peak flow 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 Agricultural under Engineering.

Now, Click on Irrigation Water Requirement under Agricultural

Now, Click on Peak Flow under Irrigation Water Requirement

The screenshot below displays the page or activity to enter your values, to get the answer for the peak flow according to the respective parameters which is the Run off Co-efficient (C), Rain fall intensity (i) and Catchment Area (A).

Now, enter the values appropriately and accordingly for the parameters as required by the Run off Co-efficient (C) is 12, Rain fall intensity (i) is 16 and Catchment Area (A) is 18.

Finally, Click on Calculate

As you can see from the screenshot above, Nickzom Calculator– The Calculator Encyclopedia solves for the peak flow and presents the formula, workings and steps too.