What are the methods for estimating the runoff?

How to Estimate Runoff from Rainfall: Top 3 Methods

Rational Method: In this method, the peak rate of runoff is given by the equation-
The Curve Number Method: This method, also known as the Hydrologic Soil Cover Complex Number method, is based on the recharge capacity of the watershed.
Soil Conservation Service Method:

How do you calculate runoff discharge?

The Rational Formula is expressed as Q = CiA where: Q =Peak rate of runoff in cubic feet per second C =Runoff coefficient, an empirical coefficient representing a relationship between rainfall and runoff.

What are the most common runoff estimation method?

The most common method of calculating the amount of rainfall converted to runoff is the SCS Curve Number (CN) Method, originally presented in the National Engineering Handbook, Section 4 (NEH-4).

What is runoff measurement?

The measurement of runoff, in the field, is generally carried out using current meters and calibrated or rated channel cross sections, flumes or standardized weirs, together with water level readings, often by automatic recorders, to give a continuous height record which can be correlated to flow.

How do you calculate discharge from rainfall data?

Find out the peak storm discharge by the Rational Method assuming that the rainfall in 5 hours is 20 cm. What will be the peak discharge if the catchment area is of clayey soil lightly covered or of steep but wooded rock? Q = 0.028 PfIcA = 0.028 x 0.10 x 0.60 x 2.98 x 80,000 = 400 cum/sec.

What is NRCS method?

The NRCS-CN method is widely applied in the estimation of precipitation runoff. It primarily relies on soil mapping and land use data as input parameters, although land use data is not frequently updated. This corrected the runoff values and improved the estimation of runoff in the watershed.

What is Khosla formula?

1) Khosla’s formula: developed for time period of the month. Khosla’s relationship for runoff estimation is given by. Rm = Pm – Lm.

What is Inglis formula?

@ : Home > Civil Engineering > Irrigation Engineering. Inglis formula is used for estimating flood discharge for. [A]. the catchments of former Bombay Presidency.

What is CN method?

The SCS-CN method predicts runoff from an expression for a rainfall-runoff curve that varies according to a single parameter called the curve number (CN). The dimensionless CN parameter describes the antecedent potential water retention of a watershed [Hawkins, 2014].

How do you find CN?

The weighted CN is calculated by taking the sum of each CN value multiplied by its fraction of the total subcatchment area. The sum is (usually) rounded to the nearest whole number, as described below. The rounded result is used for all calculations and reports.