Learn the data before using it
Water condition guides
Plain-language explanations with official references, review dates, and the limitations that keep a number in context.
A beginner’s guide to lake, river, reservoir, and tidal data
A practical starting point for choosing the right station, parameter, source, and time context.
Gage height versus streamflow
Why river height and discharge answer different questions, and why one cannot be substituted for the other.
How current water-quality data really is
The crucial difference between continuous sensors, discrete samples, and official advisories.
How lake elevation datums work
The reference surfaces behind lake and reservoir elevation numbers—and why raw values may not compare.
How to read a USGS hydrograph
A practical guide to timestamps, parameters, provisional values, and the shape of a water-data time series.
How to set useful water-level and flow alerts
Choose a parameter, threshold, cadence, and reset buffer without turning sensor noise into notification noise.
How to understand rising and falling river levels
What a trend describes, what can cause it, and what it cannot tell you about hazards.
What “provisional” water data means
Why official real-time readings can be revised and how to use their approval status responsibly.
What water temperature can—and cannot—tell you
How to interpret a station temperature without treating it as a whole-lake or safety measurement.