Collecting measurements can be risky as technicians lean precariously over bridges or hang from small cable cars suspended above swollen streams. When a flood threatens, field technicians are the critical link in getting accurate information to flood forecasters so that they can estimate the timing and size of the flood. The stage is measured continuously at a stream-gaging station located on the river. More than half of the Nation's gaging stations are equipped with satellite radios that transmit river stage data every 4 hours to the USGS, the National Weather Service, and other agencies. Extremely high water triggers instantaneous emergency transmissions.
River discharge is more difficult to measure than river stage.
To determine discharge, hydrologists, scientists who study the Earth's water systems, need to know how much water the stream's channel can carry. The capacity of the stream channel can change, so streams must be measured often, especially during high flow periods when the channel is most apt to change. During periods of high flow, field crews must go to stream-gaging stations to measure the river discharge. Although Boults and other hydrologic technicians spend a great deal of time in the field, they probably spend more time in their offices compiling and summarizing data, which are interpreted by hydrologists. A college degree is not required to become a hydrologic technician, although many technicians have at least a 2-year technical degree.