Waterconservation is one of the most important, if not the most important, concerns in a Permaculture design. We talk about harvesting the water and hold it back in the landscape. In many countries around the world water (and especially clean water) is a very limited and valuable resource.
Why is the water not clean?
There are many reasons why the water is not clean. We all know about the wastewater and garbage dumped into the oceans and our rivers. One of the worst ones in newer time (and itīs getting worse in the coming years) is the intensive farming on land there used to be forrest. When the trees are cut down the watertable will rise (because the big pumps called tree doesnt pump anymore), and it will mix with the nutrients (and traces of fungicides, pesticides & herbicides) in the soil. In Denmark (the origin of this homepage) quite a few bores have been closed on that account. In other countries the rise of the watertable bring up salts leaving a salt desert behind, and turning the rivers into high saline waterways.
How can trees clean water?
The trees "drink" alot of water. They use the nutrients keept in the water, and they return water into the air by transpiration. More than 50% of moisture returned to air comes from trees. This helps create clouds, which leads to rainfall. The trees also help creating the rain by condensation by cooling hot air down in the shade of a canopy.
The lack of trees will make the global weather more extreme by making the dryest places more dry, and the wetter places even wetter.
But water cause erosion!
It is true that water cause erosion, but it is in most cases where man have disturbed the natural environment in fx. cutting down trees. With no roots to hold the soil back it is an easy task for the water to "eat" the land.
©opyright PermAgro - PRIDK, 2001