1. Get the data. In the Salt Portal, open the station’s Measurement Group and press Export group summary. That export gives one row per gauging with its 2σ uncertainty and letter grade — which is what the fitting here relies on. Don’t use the per‑measurement export: it repeats each gauging once per probe channel, so every one gets counted two or three times. An Aquarius field‑measurement export works too.
2. Drop it on this page. Nothing is uploaded; the file is read in your browser. If the station name doesn’t match this page, you’ll get a red warning — heed it, or every number below will be wrong.
3. Check the rating. Type the equation from the Rating Curve table, or press Fit to measurements. Add a segment if the site has a break point.
4. Judge it. Points are coloured by how far off the rating they sit: green within ±7%, amber to 15%, red to 25%, black beyond. Hover any point for its detail. Tap one and press Exclude from fit if it’s a bad gauging.
5. Save it. Save site file downloads a copy with the site, the equation and the measurements built in. Put that in the SDR Field Check folder — it then works offline, which is the point in the field.

In the field: enter the staff gauge reading and your measured discharge under Field check. It tells you what the rating expects, the percent difference, and the shift that would put the measurement on the curve. Anything past 25% is a failed check — re‑measure, photograph the control, and flag it.

Chart: scroll to zoom, right‑drag to pan, drag a box to zoom in, double‑click to reset.