Rainbarrels have a fantastic capacity to irrigate and they also have huge potential as a buffer against big downpours flooding the city infrastructrue. But they only act as a buffer if they are not full. Irrigation is better if it is slow and constant and at least semiautomatic.
If we can combine a rain barrel with this type of slow irrigation we can have a far better "system" with a healthier city environment.
Now we can with the TCMTECH dripper irrigation system!
Step 1: How It Works.
If you just poke a hole in the bottom of a barrel, the water will quickly run out at first and then slow right down or the hole will block and it will stop completely. We need something with even and very slow flow. There are several ways to achieve even flow but I am convinced that this method is the simplest and easiest and will prove to be the most reliable. You simply have a float in the water in the barrelm the float is attached to or is a container, there is a little hole in the container and there is a plastic tube leading from the float to an outlet from the barrel This means that the barrel will empty at a constant rate as the float simply drops as the water empties slowly from the barrel. The picture shows a float which is a glass pot lid. The water is leaking through the steam exit hole and the tube goes through the hole that I left when I removed the handle.
Step 2: Proof of Concept Device.
Here are pictures of my first TCMTECH dripper. It is running great!
Step 3: Improvements
Well, a glass lid is not much of a float! It will eventually sink! when it tips a bit near the bottom of the barrel. So it will have to either be something lighter or it will need foam or inserts to keep it floating always. It will need a dome over it to keep out rain and dirt and it will need something as a filter for the inlet water. Also the tube leading away from the float should probably be more than 1/4 inch diameter to prevent airlocks. A L joint attaching to the outlet tube near the bung is probably a good idea too.
Step 4: Multiple Floats in One Barrel? (and Other Strange Stuff).
I think you could easily fit 3 floats in a rain barrel. And they could each be going at different speeds to water different plants or gardens. And in the previous version of dripper irrigation I had a strange refill mechanism for when it rains. maybe it could be modified to let out gushes of water at intervals (after the water exits the barrel). It is a plastic bottle version of the bamboo things that empty when they fill to a certain height in Chinese water features. (except that the water goes too different ways).