Phi Index given Total Runoff Depth Calculator

✖Total Storm Precipitation is the annual precipitation of the current year.ⓘ Total Storm Precipitation [P]			+10% -10%
✖Total Direct Runoff is the runoff entering stream channels promptly after rainfall or snowmelt.ⓘ Total Direct Runoff [R_d]			+10% -10%
✖Duration of Rainfall Excess is the total time in which the rainfall intensity the greater than the average rate of infiltration (in hours).ⓘ Duration of Rainfall Excess [t_e]			+10% -10%

✖Φ-Index of a catchment is the constant infiltration capacity that would yield the actual total runoff for a given rainfall amount.ⓘ Phi Index given Total Runoff Depth [φ]

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Phi Index given Total Runoff Depth Solution

STEP 0: Pre-Calculation Summary

Formula Used

Φ-Index = (Total Storm Precipitation-Total Direct Runoff)/Duration of Rainfall Excess
φ = (P-R_d)/t_e
This formula uses 4 Variables

Variables Used

Φ-Index - Φ-Index of a catchment is the constant infiltration capacity that would yield the actual total runoff for a given rainfall amount.
Total Storm Precipitation - (Measured in Centimeter) - Total Storm Precipitation is the annual precipitation of the current year.
Total Direct Runoff - (Measured in Centimeter) - Total Direct Runoff is the runoff entering stream channels promptly after rainfall or snowmelt.
Duration of Rainfall Excess - (Measured in Hour) - Duration of Rainfall Excess is the total time in which the rainfall intensity the greater than the average rate of infiltration (in hours).

STEP 1: Convert Input(s) to Base Unit

Total Storm Precipitation: 118 Centimeter --> 118 Centimeter No Conversion Required
Total Direct Runoff: 117.88 Centimeter --> 117.88 Centimeter No Conversion Required
Duration of Rainfall Excess: 4 Hour --> 4 Hour No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

φ = (P-R_d)/t_e --> (118-117.88)/4

Evaluating ... ...

φ = 0.0300000000000011

STEP 3: Convert Result to Output's Unit

0.0300000000000011 --> No Conversion Required

FINAL ANSWER

0.0300000000000011 ≈ 0.03 <-- Φ-Index

(Calculation completed in 00.004 seconds)

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Coorg Institute of Technology (CIT), Coorg

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< Φ Index Calculators

Total Direct Runoff Depth

LaTeX Go Total Direct Runoff = Total Storm Precipitation-(Φ-Index*Duration of Rainfall Excess)

Pulses of Time Interval from Rainfall Hyetograph

LaTeX Go Pulses of Time Interval = Duration/Time Interval

Duration of Rainfall from Rainfall Hyetograph

LaTeX Go Duration = Pulses of Time Interval*Time Interval

Time Interval of Rainfall Hyetograph

LaTeX Go Time Interval = Duration/Pulses of Time Interval

Phi Index given Total Runoff Depth Formula

LaTeX Go

Φ-Index = (Total Storm Precipitation-Total Direct Runoff)/Duration of Rainfall Excess
φ = (P-R_d)/t_e

What is Runoff?

Runoff is the flow of water occurring on the ground surface when excess rainwater, storm water, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil.

What is φ-Index?

The φ-Index of a catchment is defined as the constant infiltration capacity that would yield the actual total runoff for a given rainfall amount. In principle, the magnitude of the φ index is bounded between the catchment's maximum and minimum average infiltration capacities during a rainfall event.

How to Calculate Phi Index given Total Runoff Depth?

Phi Index given Total Runoff Depth calculator uses Φ-Index = (Total Storm Precipitation-Total Direct Runoff)/Duration of Rainfall Excess to calculate the Φ-Index, The Phi Index given Total Runoff Depth formula is defined as the constant infiltration capacity that would yield the actual total runoff for a given rainfall amount. Φ-Index is denoted by φ symbol.

How to calculate Phi Index given Total Runoff Depth using this online calculator? To use this online calculator for Phi Index given Total Runoff Depth, enter Total Storm Precipitation (P), Total Direct Runoff (R_d) & Duration of Rainfall Excess (t_e) and hit the calculate button. Here is how the Phi Index given Total Runoff Depth calculation can be explained with given input values -> 0.03 = (1.18-1.1788)/14400.

FAQ

What is Phi Index given Total Runoff Depth?

The Phi Index given Total Runoff Depth formula is defined as the constant infiltration capacity that would yield the actual total runoff for a given rainfall amount and is represented as φ = (P-R_d)/t_e or Φ-Index = (Total Storm Precipitation-Total Direct Runoff)/Duration of Rainfall Excess. Total Storm Precipitation is the annual precipitation of the current year, Total Direct Runoff is the runoff entering stream channels promptly after rainfall or snowmelt & Duration of Rainfall Excess is the total time in which the rainfall intensity the greater than the average rate of infiltration (in hours).

How to calculate Phi Index given Total Runoff Depth?

The Phi Index given Total Runoff Depth formula is defined as the constant infiltration capacity that would yield the actual total runoff for a given rainfall amount is calculated using Φ-Index = (Total Storm Precipitation-Total Direct Runoff)/Duration of Rainfall Excess. To calculate Phi Index given Total Runoff Depth, you need Total Storm Precipitation (P), Total Direct Runoff (R_d) & Duration of Rainfall Excess (t_e). With our tool, you need to enter the respective value for Total Storm Precipitation, Total Direct Runoff & Duration of Rainfall Excess and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

How many ways are there to calculate Φ-Index?

In this formula, Φ-Index uses Total Storm Precipitation, Total Direct Runoff & Duration of Rainfall Excess. We can use 1 other way(s) to calculate the same, which is/are as follows -

Φ-Index = (Intensity of Rainfall-Runoff in Cm from 24h Rainfall)/24

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