How to Read a USGS River Gauge
A river gauge page can look technical at first, but most of the useful information comes down to a few measurements: flow, stage, trend and context.
1. Start with streamflow
Streamflow tells you how much water is moving past the gauge and is usually reported in cubic feet per second, or CFS. Higher CFS means more water is moving, but what counts as high depends on the river.
2. Check gauge height
Gauge height shows the water-surface level at that station. It is valuable for seeing whether the river is rising or falling and for comparing the current level with NOAA action or flood stages where those thresholds exist.
3. Look at the trend
A current number is more useful when you know where it is headed. A 24-hour rise or fall shows whether conditions are changing. Get Water Data only labels a 24-hour trend when there is enough recent data to make that comparison.
4. Add historical context
A river can be rising and still be below normal, or falling while still running much higher than normal. Comparing current flow with the historical median for the date adds the seasonal context that a raw CFS number lacks.
5. Use flood thresholds carefully
Where NOAA flood-stage data is available, compare the current stage with action and flood stages. These thresholds are station-specific and should not be transferred to another gauge.
Keep learning
These guides summarize public technical information in plain English. Measurements and official thresholds should always be checked at their original source when making safety or flood decisions.