Rainwater Harvesting

Fresh water is of critical importance to most plant and animal life on land.

Rain water is the biggest single source of fresh water.

Rainwater harvesting covers the techniques for capturing, filtering and storing rain water, in order to prepare it for use.

Techniques

Two fundamental technologies are required:

A collector is needed, to capture the water. The collector may be a the side of a hill, a roof, solar panels - or a dedicated structure.
A container is usually required to store the water. The container may be a dammed valley, a pond, a well - or a water storage butt.

If clean water is needed, filtration techniques may need to be applied. These need not be very sophisticated - if the water is to be used to feed plants - since plants do their own water filtration.

Sometimes - particularly if the container is low-lying - pumps may be needed to move the water to where it is required.

The storage facility may consist of a series of containers, linked by continuous siphons or overflow pipes:

Water butts linked by a continuous syphon

Water butts linked by overflow pipes

Some systems make an effort to intercept the rain as soon as possible - since once the water reaches the ground it starts getting muddy and polluted.

Sometimes, rainwater harvesting systems are also used to generate hydro-electric power.

Plants

Plants are masters of rainwater harvesting. They allow water to soak into the ground - and then they suck it back out again using a distributed network of fine roots.

Gunnera leaf drainage patterns

Plant funnel

Plant guttering

Plants tend to use most of the water they collect.

We can eat them, eat their fruit - or draw inspiration from their designs.

Dew Harvesting

Please see also our dew harvesting page.