Rainfall collecting - experimentation.

Today I woke up just in time to see dark clouds gathering on the horizon for an incipient thunderstorm. Rain was imminent in about fifteen to twenty minutes, considering it was already drizzling, and although this usually means it's the kind of day where I can stay in bed while I can help it, today I had a small experiment to perform.

For science. And survival. And science, of course.

For this experiment, I required a small frame which I'd put together over the last couple of days. Nothing fancy, just three comparatively short lengths of bamboo lashed together in a U-shape and a sheet of plastic about a couple of square meters in area. Next came two plastic stools as support.

Added to this were three identical five-liter buckets I temporarily purloined from my mother's laundry supplies, and armed with these, I headed downstairs where there was a reasonably open area.



Bucket one was situated in an open field.

Bucket two was situated at the foot of one of the apartment blocks where the rainfall would be funneled off the roof and run down the wall in a cascade.

Bucket three was situated in the same open field, this time with the framed funneling device. a paperweight was added near the open end to create a dip and makeshift spout so water that fell onto the sheet would pour into the collecting bucket.

Reason why I picked bamboo is because it's lightweight, cheap, commonplace and strong. I'm not kidding - a common way to hang laundry here is to fix one end of a 2-3 meter long bamboo pole to a wall/holder, affix your laundry onto it, and hang it out the window. Decades of Singaporean housewives haven't worried about it snapping, so you don't need to. Hong Kongers even use it in scaffolding instead of steel.

Of course, if you don't have bamboo, some metal or god forbid, plastic poles will do, so long as they're strong enough.

Plastic sheeting is also relatively common, and while there are health concerns, I can't really think of an equally commonplace substitute off the top of my head.

So to recap:

• Three short bamboo poles, connected in a rough U-shape with square lashings. Plenty of twine was used.
• One plastic sheeting about a couple of square meters in total area, affixed to the bamboo with duct tape.
• One paperweight to weigh down the open end and create a nice, neat funnel.
• This frame was set in between two plastic stools as support.

Perhaps if I'd wanted more stability, I could have gone for a four bamboo poles to make a proper frame and poked a hole in the middle as the funnelling spot, instead of leaving one side open for it. Hmm...

In any case, I timed the thunderstorm from the moment the buckets were set out (it lasted forty-one minutes) and tallied the number of times I had to empty each bucket. The results are as follows:

Bucket one: three times, about 1/3 left over.
Bucket two: ten times, about 2/3 left over.
Bucket three: seven times with just a bit in the bottom.

Such a rainstorm can be reasonably expected every two to three days, with slight variance for the dry/wet seasons. Bucket two collected more water than three, since it had most of a rooftop to work with (although there were other leaving funnels from the whole roof), but while there was a greater volume I'd rather not drink traces of paint, rust, moss and whatever the rainfall picks up while running down the side of the building. Given that my daily water intake is about 2-2.5 liters, which is likely to be more with physical exertion, the bucket/makeshift collector should work if I can get somewhere to store the water, and I can easily rig up more of these makeshift collectors in an hour or two.

No, it won't be perfectly clean water, but it's much better than scooping something out of a storm drain and I know the cartridges in my water filter will eventually run out. If I die in a SHTF scenario, it probably won't be from thirst.