Stage (hydrology)

{{Short description|Water level in a river above a reference height}}

{{distinguish-redirect|River stage|Riverstage}}

{{more sources|date=November 2024}}

In hydrology, stage is the water level in a river or stream with respect to a chosen reference height.{{cite web |title=What does the term "stream stage" mean? |url=https://www.usgs.gov/faqs/what-does-term-stream-stage-mean#:~:text=%22Stage%22%20is%20the%20water%20level,20%20feet%2C%20sometimes%20very%20quickly. |website=usgs.gov |publisher=United States Geological Survey |access-date=8 November 2024}}{{cite encyclopedia |last1=Schumm |first1=Stanley A. |last2=Dury |first2=George Harry |last3=F.Ritter |first3=Dale |last4=K.Lustig |first4=Lawrence |title=River - Streamflow and sediment yield |date=2 November 2024 |encyclopedia=Encyclopedia Britannica |url=https://www.britannica.com/science/river/Streamflow-and-sediment-yield#ref399599 |access-date=8 November 2024}} It is commonly measured in units of feet. Stage is important because direct measurements of river discharge are very difficult while water surface elevation measurements are comparatively easy. In order to convert stage into discharge, a rating curve is needed. Hydrologists can use a combination of tracer studies, observations of high water marks, numerical modeling, and/or satellite or aerial photography.