"Gauge height" (also referred to as "stream stage", "stage of the [body of water]", or simply "stage") is the level of the water surface above an established zero datum at a given location.[2] The zero level can be arbitrary, but it is usually close to the bottom of the stream or river or at the average level of standing bodies of water. Stage was traditionally measured visually using a staff gauge, which is a fixed ruler marked in 1/100 and 1/10 foot intervals,[3] however electronic sensors that transmit real-time information to the Internet are now used for many of these kinds of measurements.[4] The flood stage measurements are given as a height above or below the zero level. Levels below zero are reported as a negative value.