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Water Science Pictures
Water measurements: Downloading stream gage heights to a USGS database

The U.S. Geological Survey has thousands of these stream-gaging systems installed nationwide. It is still the most common way to measure the heights (and, indirectly, the amount of water flowing at any given time) of streams. The technology is changing. More modern systems, like the one shown here, detect the heights of streams and transmit that information through satellites to a USGS office.

In the past, the most common type of stream gage worked by recording stream height on a moving paper roll. Nowadays, gage heights are stored electronically in the instrument in the metal box. The box sits on top of a big, vertical pipe that goes down into the creek. A continuous record of the height of the river is stored in the instrument, and when a technician visits this site, he/she connects their laptop computer to the logger's memory and downloads the data.

Some of these gage houses have a satellite-transmission system that can upload data right to the USGS office -- essentially a real-time system.