# How to Calculate Discharge?

If length is measured in feet and time in seconds, discharge has units of feet3/sec or cubic feet per second (cfs). Depth times width gives the cross-sectional area. The shape of the channel is important because of the reduction in velocity due to friction along the channel margins.

## How to Calculate Discharge?

Calculating the discharge of a river or stream is an important part of assessing the health of a watershed and understanding the hydrology of an area. Discharge is the volume of water flowing through a given cross section of a river or stream over a certain period of time and is usually expressed in cubic meters per second (m3/s). Knowing the discharge of a river or stream is essential to determining the size of the watershed, the flow rate, and the amount and type of sediment carried by the water.

The most common method for calculating a river’s or stream’s discharge is the use of a stage-discharge or stage-storage graph. This graph is a graphical representation of the relationship between the water level, or stage, of a river or stream and the discharge. To calculate the discharge, the water level or stage is measured and then the corresponding discharge is read off the graph.

In addition to the stage-discharge graph, there are several other methods for calculating a river or stream’s discharge. One is to use a weir, which is a structure placed in the river or stream that controls the flow of water. The weir is designed to measure the flow of water over a given period