Insights
What the data Hydrionis holds is actually showing, worked out rather than asserted. Each of these is one question, answered from the governed record, with the chart, the method, the sources and the limits on the same page.
Findings
How long the chalk remembers the rain →
One of the longest continuously read groundwater records anywhere sits in a chalk valley in the South Downs. Set its water level beside England’s rainfall and the aquifer’s memory becomes visible: the level answers the rain, but not in the month the rain fell.
How fast different aquifers answer the rain →
The same test run against every English borehole with a long enough record. Response times differ by months between sites, which is why a national drought statement says little about any particular supply.
How well a snowpack predicts the year its river had →
The same test run in every American basin holding both a snow pillow and a stream gauge. In most of them the winter snowpack explains the river’s year well. In a handful it runs backwards, and those are the informative ones.
The comparisons Hydrionis will not draw →
Six relationships are declared as scientifically legitimate. Most of them cannot currently be built from the data held, and this is the list of which, and exactly why.
Deeper work
Insights answer one question from current data. Longer analyses, with their own methodology and release notes, are in Research. The datasets behind both are in the dataset catalogue.