We got some rain last night, about 3mm or so, with more on the way over the next few days. So I’m finding myself thinking about rainwater collection. I’ve already got a plan to install an array of butts behind the shed this autumn which should be able to save a kilolitre or so and Fi’s OK’ed the budget to buy them (since I’m not earning these days) since it’ll help keep the rabbits' lawn fresh.

What’s a little more interesting is considering how the geodesic dome could function as a rainwater collection system when it’s not in use as a shaded seating area. Here’s a picture of the dome, taken in 2000 when it first went up.

You can see there’s two large horizontal planes with three rows of connectors, and then the crown. The bottom line of connectors sits on the stands and raises it up. The middle line of connectors is what I’m interested in.

If you were to suspend a circular disk from this middle line its area would be about 12m². According to the research I did (and please tell me if I’m wrong) volume of water in l = area of collection in m² x rainfall in mm. So last night’s 3mm, if I’d been able to collect it from within the dome, would have come to 36 litres. Which is not insubstantial.

The easiest way to collect it would be to get a 4m diameter circle of canvas (or parachute!), punch eyelets around the circumference and hang it from the dome connectors, then cut a hole in the middle so the water runs into a container. Job done! The downside is we then have many litres of water in a container in the middle of the dome. If the container is large enough to be worth it it’ll be too large move. So maybe a gutter to run it outside the dome.

Anyway, those are niggles that can be solved later. The main thing is, do we want to sacrifice the dome in this way. Plenty to ponder.

Practical Engineering: Are beavers actually good at dams?

This video ticks so many boxes for me. 1) It’s about damn engineering, which is interesting as a 20th century phenomena for its awesome scale and unforseen side-effects. The science is really interesting and the cultural metaphors are delicious. Next there’s beavers, who have been a hot topic recently for their employment in rewilding efforts, damning streams to create wetlands which prevent run-off and erosion, something we’re about to see a lot of once this drought turns into floods. And then there’s how beavers actually build damns and how that compares to how humans do, which is really really fascinating. I can highly recommend this to all you nerds. (I also really wanted this to be a collaboration with Ze Frank on the beaver sections…)

• Carole Cadwalladr: A Digital Lynching — Someone who has been on the receiving end of a right-wing pile-on reflects on Jason Arday’s death and offers advice on how to help the inevitable next victim.
• Pre-Raphaelite Sisterhood — ‌On Furiosa and Hylas and the Nymphs — I’m working on my new website with imports of old posts and found myself revisiting my review of Furiosa, specifically the bit where one of the post-apocalypse guys was painting a pre-raph mural. I wondered if anyone knowledgable had written about it and had a search. Bingo.
• Mastodon 5.0: Laying the foundation — The web interface for Mastodon has always been embarrassing and this looks like a massive improvement. I might even stop using an app…