How to interpret gage height and streamflow values
- Gage height (also known as stage) is the height of the water
in the stream above a reference point. Gage height refers to the elevation
of the water surface in the specific pool at the streamgaging station,
not along the entire stream. Gage height also does not refer to the
depth of the stream. Measurements of gage height are continually recorded
by equipment inside a gagehouse on the streambank.
- Streamflow (also known as discharge) is the volume of
water flowing past a given point in the stream in a given period of
time. Streamflow is reported as cubic feet per second (ft3/s).
Streamflow values are better indicators than gage height of conditions
along the whole river. Measurements of streamflow are made about every
six weeks by USGS personnel; they wade into the stream to make the measurement
or do so from a boat, bridge, or cableway over the stream.
- For each streamgaging station, a relation between gage height and
streamflow is determined by simultaneous measurements of gage height
and streamflow over the natural range of flows (from very low flows
to floods). This relation provides the real-time streamflow data
from that station. All real-time data are provisional
and subject to revision.
|
