Rainwater harvesting... our first crop failure!

Late October 2019

One thing you can rely on with the English weather is that it will generally be wet at some point. What you can’t rely on is when, and in what quantity. So when embarking on a program of planting trees, shrubs and climbing plants, it’s a good idea to have a reliable water supply ready.

Consequently, as we have no building roofs from which to channel run-off water, we decided to construct a rainwater collection device.

The idea we came up with was a gazebo, with the roof inverted to form a funnel, the nadir* of which would point into the top of a 210L water barrel. The top of the barrel would be open, with a fine mesh strapped over it to filter out larger particles, leaves and suchlike.

(*Technically, the opposite of an apex…)

I had worked out that under the 3m x 3m roof I could arrange up to 15 water butts, allowing room to move among them, so collecting up to about 3100 litres (that’s about 690 gallons in old money) of free water, on tap(s).

I drilled through the corner junction pieces so that the gazebo roof could be assembled upside down on its legs, taped the pole joints so that they didn’t inadvertently come apart, then we assembled the rig, and waited. . .

Sure enough, as we had been experiencing quite a lot of rain recently, it rained again that night, and on my way home from work the following day, I eagerly headed to Stackmoor to check on the success, or otherwise, of our creation.

… I was, sadly, disappointed...

Well, partially anyway. The funnel worked! There was a fairly large accumulation of water still in the funnel as the drainage holes were not large enough to allow a steady flow (more a mean dribble) into the barrel. So, once I had opened these a little bit wider the water began to flow more freely. I attached a clear hose to the tap and looped it over the frame above, to act as a level meter, opened the tap and... Nothing!

Um… After some investigation . . . it turns out the tap had been left open all night . . . accounting for the damp patch I was kneeling in… *SMH*

Having now corrected this oversight, I closed the tap and left site.

The following evening, on my way home from work, I again visited Stackmoor to check on progress. This time I was rewarded with at least 30L of water in the barrel. Yay! There was still a pool in the gazebo funnel, so I added a few more drainage holes, straightened the structure (which had developed a bit of a lean) and with higher hopes, left Stackmoor.

. . . The next evening, I approached the site with some trepidation. The previous night and day there had been a particularly heavy downpour, and high winds gusting up to 80mph (according to the BBC forecasts). The funnel was a wreck! The barrel had accumulated maybe another 5-10L of water and was still standing (is still standing), but the funnel contraption was a complete write-off.

Undaunted, I reported the – not too surprising – events to my co-constructor, but instead of becoming despondent at the loss, we immediately set about planning the Mk2 collector.

As at writing (mid-November), we are waiting for the poles we ordered to be re-stocked so that we can erect a more permanent, and resilient, framework. Please do look out for an update in the not too distant future.