The Scorecard gives an overall view of the water quality from the chemical, bacterial, and ecological test samples together with the environmental context where this is available.
Scroll through the card to see the elements used to rate the general health of the water and the river environment.

The first page of the scorecard gives the overall summary view and the second and third pages expand to giver more information and details where they are available

The scorecard and the rankings used are a draft and may change as we understand better the overall picture of the river and factors influencing its health.

Each spoke on the wheel is scored by the share of samples from the last 12 months that pass a simple test based on the notes we use on the colourimetric cards and in the field guide. For the water chemistry and bacteria spokes, the test is a threshold: phosphate at or under 0.05 mg/L (as phosphorus), nitrate at or under 2 mg/L (as nitrogen), total dissolved solids (TDS) from conductivity at or under 400 µS/cm, and E. coli at or under 1,000 colony-forming units (CFU) per 100 ml, the England bathing water figure.
Clarity scores from the the share of visual checks rated “clear”, and pollution scores the share of surveys with no foam, scum, oily sheen, litter or odour.
The invertebrates (INV) spoke uses Riverfly results, scoring the share of samples at or above each site’s trigger level.
Readings where the Water Rangers QA process flagged “Issue detected” are left out - often caused by people entering a value of "0" rather than leaving the entry blank ... Zero means something!
Where samples use different test kits for the same thing chemical, readings are converted to a common unit first, so they can be scored together.

A spoke needs at least 12 samples in the period (6 for RiverFly) to be scored. With fewer, it shows grey as “not enough data” rather than risk a misleading grade. Each spoke’s percentage gives its colour on the wheel: A (Excellent) from 80%, B (Good) from 60%, C (Fair) from 40%, D (Poor) from 20%, and F (Very poor) below that. The overall grade in the centre is the average of the scored spokes only, so grey spokes don’t pull it down.