Streams are a natural resource that can influence economic growth and the development of communities. They supply water for many uses, provide habitat for aquatic plants and animals, and sup-port recreational activities such as boat-ing and fishing. The amount of water (flow) in a stream — either too little or too much — can seriously affect these uses and human life. By using a method called stream gaging , information about the flow in a stream and the fluctuations in that flow can be obtained.
n its simplest form, stream gaging may consist of measuring any number of the following stream characteristics: stage (or depth), cross-sectional area, velocity, and (or) flow (or discharge). When the depth and velocity are measured at several points across the stream channel so that the flow (or discharge ) is calculated, a streamflow measurement (or discharge measurement ) is made.
By making streamflow measurements at the same site on a stream over a wide range of stages, a relation between stage and discharge can be developed. This relation can be used to provide information on the magnitude and fluctuations of flow on a stream. If long-term or continuous information is needed on a specific site, a stream-gaging station can be established. A stream-gaging station is a site where stage is monitored and recorded and streamflow measurements are made to provide a stage-discharge relation.
Ever since the first documented streamflow measurement was made in Ohio — on the Sandusky River — stream-gaging information has been used to minimize the effects of floods and droughts, determine locations for water intakes and wastewater-treatment plants, and provide data for many other uses. Today, stream gaging is a routine activity in managing the State’s water resources.