(It might not even be your fault either)
I wrote this so that I'd have some idea about the river levels of the Cam, upon which I live. Partly so that I'd know if I could safely cycle under the bridge at Mitcham's Corner.
I did ask the EA if I could access their API but they said, "No". So I investigated alternatives and found that while they publish river levels online they don't do so in an easily scrapable way.
Then I found YQL and it's ability to query sites with added XPATH goodness. So I wrote a couple of PHP classes to get the data I needed and sling it into MySQL where I could extract it and chart it historically.
I make no claims to the validity of this data. If you sink, drown or get attacked by ducks it's simply not my fault. I wanted the data, if you're happy to not hold me responsible for anything then please look at the data I collected for myself. If you're likely to think something is my fault then don't look!
You've been warned!