The image above represents unit hydrograph.

To compute for unit hydrograph, two essential parameters are needed and these parameters are **Direct run off (DRO) **and **Effective depth (ED).**

The formula for calculating unit hydrograph:

UHG = ^{DRO} / _{ED}

Where:

UHG = Unit Hydrograph

DRO = Direct Run Off

ED = Effective Depth

Let’s solve an example;

Find the unit hydrograph when the direct run off is 11 and the effective depth is 13.

This implies that:

DRO = Direct Run Off = 11

ED = Effective Depth = 13

UHG = ^{DRO} / _{ED}

UHG = ^{11} / _{13}

UHG = 0.846

Therefore, the **unit hydrograph **is **0.846.**

**Calculating the ****Direct Run Off when the Unit Hydrograph and the Effective Depth is Given.**

DRO = UHG x ED

Where;

DRO = Direct Run Off

UHG = Unit Hydrograph

ED = Effective Depth

Let’s solve an example;

Find the direct run off when the unit hydrograph is 21 and the effective depth is 10.

This implies that;

UHG = Unit Hydrograph = 21

ED = Effective Depth = 10

DRO = UHG x ED

DRO = 21 x 10

DRO = 210

Therefore, the **direct run off **is **210.**

**Calculating the Effective Depth when the Unit Hydrograph and the Direct Run Off is Given.**

ED = ^{DRO} / _{UHG}

Where;

ED = Effective Depth

DRO = Direct Run Off

UHG = Unit Hydrograph

Let’s solve an example;

Find the Effective Depth when the Direct Run Off is 250 and the unit hydrograph is 50.

This implies that;

DRO = Direct Run Off = 250

UHG = Unit Hydrograph = 50

ED = ^{DRO} / _{UHG}

ED = ^{250} / _{50}

ED = 5

Therefore, the **effective depth **is **5.**

Nickzom Calculator – **The Calculator Encyclopedia** is capable of calculating the unit hydrograph.

To get the answer and workings of the unit hydrograph 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 **Hydrology II **under **Agricultural**

Now, Click on **Unit Hydrograph **under **Hydrology II**

The screenshot below displays the page or activity to enter your values, to get the answer for the unit hydrograph according to the respective parameters which is the **Direct run off (DRO) **and **Effective depth (ED).**

Now, enter the values appropriately and accordingly for the parameters as required by the **Direct run off (DRO) **is **11 **and **Effective depth (ED)** is **13**.

Finally, Click on Calculate

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