Monday 12 June 2023


We don't run a weather station Chez Blob, although gathering & tricking about with scads of data might be a good fit for obsessive me. We are blessed with data from 30km to the north by sharing a county with Alan O'Reilly at CarlowWeather. It's not quite the same weather because Mt Leinster rises between us, but O'Reilly keeps meticulous records, makes them available, and they are usually good enough

We collect rain-water because the plastic of the polytunnel is, like, waterproof and there's a feast of salad underneath. The N and S edges of the plastic bottom out into gutters [neatly levelled by Kamil and Rene last Summer] and rain is diverted thence to a pair of herring barrels at the SE and NW corners and a 1 tonne IBC inside the NE corner. The N side of the tunnel is about 500mm higher than the S and this allows us to quietly siphon water from "on high" to plants and buckets that little bit lower. Like everyone else in the count[r]y we had a good spill of rain on Mon 15th May which recharged all our containers . . . then nothing: for days, then weeks. It was like 2018 all over again when I wrote about 22 days without rain and nationwide hose-pipe bans.

After a week without rain we had distributed all our reserves and had to start pumping water from our bore-hole to service the lettuce and peas. After two weeks, the grass on the thin soil of the front yard was turning beige and umber. Dau.II announced that now would be a good time to clean out all our water containers and that involved disconnecting our two 1-tonne IBCs and going at the inside with a yard-brush. I could get inside the herring barrels [R] to give them a robust scrub and a touch of bleach. After an afternoon of heaving and rolling, everything was sparkling and sweet-smelling . . . and ready for more rain. 

I wasn't until Sat 10 June that we got any! After the droughty weeks it seemed like a lot and we took off all our clothes and danced to give thanks to the Great God Pluvium. On Sunday morning, The Beloved asked How much rain did we get yesterday? To which I replied If you wait a bit, I've just plumbed the depths of the herring barrels and need to do the calcs. The total catchment of the tunnel is 17m x 9m = 150 sq.m. or 1,500,000 Volume of an cylinder = π.r^2.depth

NW barrel: ⌀ 40cm was 35cm full = caught vol 43lt = 43,000 cc ; area served 375,000
 so rainfall 1.1mm
SE barrel ⌀ 50cm was 30cm full = caught vol 58lt = 58,000 cc ; area served 750,000
so rainfall 0.8mm

That seems scarcely credible and it's at variance with what O'Reilly recorded 30km North. But I had checked Met Eireann's rainfall radar at about lunchtime and it showed that we were between two belts of feeble rain moving SE to NW. I also checked out two wheelbarrows which had been left out through the 24 hours - they had but a few tablespoons of water in their downhill corners. So my best guess is that we had 1mm of rain on Saturday after getting nary a drip for 25 days.

“The rain it raineth on the just
And also on the unjust fella;
But chiefly on the just, because
The unjust hath the just’s umbrella.”[prev]

No comments:

Post a Comment