How is rainfall depth calculated?

Measure the diameter of the bucket at the bottom in the same way. Calculate the average of the two diameters. Divide by two to find the average radius. Find the average volume of rain = Depth x radius x radius x 3.14.

How do you convert rainfall depth to intensity?

In order to have the average rainfall intensity in m/s corresponding to that interval of time, you have to divide the rainfall depth for the number of seconds in the time interval or for mm/s you multiply for 1000/21600. If you want the intensity in m/h you divide for 6 hours.

How do you find the maximum depth of rainfall?

The first thing that you have to do is to convert the table of annual maximum (statistical) values of rainfall depth into Intensity Values (mm/hr) just divide the total depth (precipitation) by the rainfall duration (i.e. for 1971 during 1 hr you have a rainfall max.

How many mm is heavy rain?

Heavy rain: Greater than 4 mm per hour, but less than 8 mm per hour. Very heavy rain: Greater than 8 mm per hour. Slight shower: Less than 2 mm per hour. Moderate shower: Greater than 2 mm, but less than 10 mm per hour.

How many Litres is 1mm of rain?

With a rainfall of 1 mm, every square metre receives 1 litre of rain water. A rainfall of 1 mm supplies 0.001 m3, or 1 litre of water to each square metre of the field. Thus 1 ha receives 10 000 litres.

How rainfall is measured in cm?

It is expressed as cm per hour or mm per hour. Rainfall is measured by means of rain gauges. The shank of the funnel is put in a receiving bottle capable of taking 10 cm of rainfall. The rainfall collected in the bottle is measured with the help of a graduated measuring cylinder furnished with each rain gauge.

How do you calculate rainfall intensity of rainfall data?

Formula Of Rainfall Intensity The intensity of rainfall (p) in mm/hr is given by the following general formula: p = 254a / (t+b) mm/hr Where, t = Duration of storm in minutes, a and b are constants. a = 30 and b = 10 when t is 5 to 20 minutes. a = 40 and b = 20 when t is 20 to 100 minutes.

What is intensity of rainfall?

Rainfall intensity is defined as the ratio of the total amount of rain (rainfall depth) falling during a given period to the duration of the period It is expressed in depth units per unit time, usually as mm per hour (mm/h).

Which is method of finding rainfall?

1) Arithmetic Mean – This technique calculates areal precipitation using the arithmetic mean of all the point or areal measurements considered in the analysis. 2) Isohyetal Analysis – This is a graphical technique which involves drawing estimated lines of equal rainfall over an area based on point measurements.

What is rainfall in hydrology?

Introduction. Rainfall is the amount of precipitation, in the form of rain (water from clouds), that descends onto the surface of Earth, whether it is on land or water. Atmospheric turbulence and convection carries the moisture, or water vapor, upward into air masses where they form clouds.

What is meant by 1 cm rainfall?

1 cm of rainfall means that a volume of water equal to 10 L has fallen over an area of 1 m²; ergo, the basic conversation for rainfall depth (say mm) to volume is: 1 mm of rainfall depth equates to 1 L of rainwater per m².

How to find the average depth of rainfall over a catchment?

For any time duration, the average depth of rainfall falling over a catchment can be found by the following three methods: 1. The Arithmetic Mean Method 2. The Thiessen Polygon Method 3. The Isohyetal Method. 1. The Arithmetic Mean Method:

How do you measure rainfall?

The most common rainfall measurement is the total rainfall depth during a given period, expressed in millimeters (mm). For instance, we might want to know how many millimeters of rain fell over the course of 1 h, 1 day, 1 month, or 1 year. You can easily get a rough measurement of rainfall depth at home.

How do you find the point of equal depth of precipitation?

The points of equal depth of precipitation can be computed by the method of estimation from the rainfall values of rain- gauging stations. In Fig. 2.8 dotted lines show iso-hyetes and the outer most firm line is basin boundary.

How accurate is the rainfall depth on the device?

The rainfall depth (in mm) quickly increased between 13:00 and 14:00, meaning that it rained a lot during that period. During a period of light rain, this device is not very precise. For example, between 05:15 and 13:00, all you can tell is that 0.2 mm of rain fell (one tip of a bucket), but you do not know exactly when that rain fell.