Hyetograph

The plot between rainfall intensity and time is called a hyetograph. It is a graphical representation of the rainfall intensity over a specific period. The hyetograph is an essential tool in hydrology, used to analyze and design drainage systems, reservoirs, and flood control structures.

Components of Hyetograph

The hyetograph is made up of two components: the rainfall distribution and the time axis.

Rainfall Distribution

The rainfall distribution represents the intensity of the rainfall at different points in time. The distribution of rainfall is usually measured in millimeters per hour or inches per hour. The rainfall distribution can be represented using different types of curves, such as a triangular shape, a trapezoidal shape, or a bell-shaped curve.

Time Axis

The time axis represents the time interval during which the rainfall occurred. The time axis is usually represented in hours or minutes. The time interval can be divided into equal time intervals, such as 15 minutes, 30 minutes, or 1 hour.

Types of Hyetograph

There are two types of hyetograph:

1. Point Hyetograph - A point hyetograph represents the rainfall intensity at a single point in time. It is used to determine the maximum rainfall intensity and the time duration of the rainfall event.

2. Spatial Hyetograph - A spatial hyetograph represents the rainfall intensity at different points in time and space. It is used to determine the runoff volume and peak flow rate in a watershed.

Conclusion

In conclusion, the hyetograph is a graphical representation of the rainfall intensity over a specific period. It is essential for analyzing and designing drainage systems, reservoirs, and flood control structures. The hyetograph is made up of two components: the rainfall distribution and the time axis. There are two types of hyetograph: point hyetograph and spatial hyetograph.

Hdrograph is graph between discharge and time where heytrogrph graph between time and rainfall intensity , it's area give depth while hdrograph area gives volume