By Andy Williams.
Bucket is wise. Bucket can tell us things. Bucket can be a surprisingly illuminating diagnostic tool. Hang on and I’ll tell you all about it.
I dug this hole back in March, so I could use the soil as a mound for the hazel tree we planted on it. We have many such holes around the croft that were dug at the same time, and they’ve been surprisingly interesting. We knew the ground here gets saturated very quickly when it rains very soon after buying it. As soon as we started planting we learned that we had roughly 18 inches of good topsoil over clay subsoil. Since we intend to dig ponds eventually this was excellent news, but it affects the hydrology of the site. At least one of us walks the fence line every day, checking the trees, so it’s easy to keep an eye on these holes. Immediately after rain they have up to four inches of water in them, draining to an inch or so within three days, and being no more than moist within four to five days. I put this down to a combination of water being infiltrated into the ground and the drying effect of the wind. Soon after we planted the trees I found the bucket jammed between some rushes. I shoved it into the hole so it wouldn’t blow away, intending to pick it up later, and promptly forgot about it until every time I passed the tree.
It added another dimension to water table observation. I’d read about using a bucket to monitor rainfall in a book I read years ago, but the author hadn’t thought of sticking it in a hole to get two sets of data. I really wish I could claim credit for it properly.
Typically, you stick a bucket somewhere it won’t blow away and watch it over a year. It’s as simple as that. If it always has water in it you have a wet climate. If it often dries completely you have a dry climate. All pretty obvious so far yes? Where it’s useful is in determining unusually dry spells, when pasture may need extra water to stay alive. Unlike proper rain gauges the bucket factors in moisture lost to the wind. It won’t however factor in moisture lost to ground infiltration, but my hole does (seriously, stop sniggering). Rain in Caithness is regular but not very often too heavy. In terms of inches of precipitation it’s similar to Kent, apparently. Windier though. The bucket has so far not gone beyond half full, but hasn’t gone lower than four inches deep either. The sun and wind evaporate the moisture fairly consistently, so will be having a similar effect on the pasture. Our soil isn’t waterlogged, it’s intermittently wet because moisture is slow to percolate through the clay subsoil. And that can be fixed easily through sensitive earthwork construction. It’s a game changer for our understanding of this site. And that, I think you’ll agree, isn’t a bad result from a forgotten bucket.