#danirambles

I knew Venice is—famously even—a bunch of islands in a lagoon. I knew a lagoon is a salt water environment. I've known all this for several decades at this point. In fact, I know a lot more about Venice than this because it is a city in which a lot of my various interests tend to pass through at some point. In all this time I don't think I ever stopped to question where the drinking water came from. So immediately I had to read the whole blog post in fascination because it's actually so simple in how it works and so smart and I'm like over here cheering on the homies who worked out a great and simple solution thousands of years ago, and thanking them because it helps me now!

This illustration comes from the previously linked blog post. Basically what they'd do is dig these wells that don't collect groundwater (which is again, salty. Do not drink the salt water, kids.) No, these wells are actually rain collection cisterns! Like many people across history and cultures without reliable access to safe ground water, capturing water from the air became essential. So the Venetians would do this by digging these craters and sealing the bottom with clay to keep good rainwater in and bad lagoon water out (an issue they constantly battled and I imagine still do). Next they filled the crater with levels of different sands until they hit street level, but Crucially! The well cistern in the center is set at the highest point and the ground slopes towards the corner grates. Last they'd build the brick cisterns underneath the drains and well, and finish tiling. I imagine the rest of the courtyard would also have additional engineering to support this too.

Then when it rained, the water would get corralled to the grates where it filled the attached cistern and slowly leech into the sand, filter through the sand towards the well cistern, and finally get to the well cistern scrubbed of a lot of nasties and good enough to drink!