It seems strange to a lot of people that an Island as small as Tenerife, should have, what seems like a never ending flow of water, after all it doesn't rain very often.
'THE PINE FORESTS' that is the answer to the question.
The pine trees collect the water from the dew at night, the clouds that at times cover the mountains, the rain fall when it comes and the water from the melting snows during the winter months.
All this water passes into the ground via the roots of the pine trees, where it sits in natural underground reservoirs.
It was the Arab's, experts in transforming dry land into arable land, who introduced irrigation into Spain, the Spanish conquistadors passed on the knowledge to the Canary Islands , adapting to the conditions and materials of the Islands.
Villages grew around the natural springs, as villages grew the water had to be carried further afield for domestic and agricultural use. This was achieved by the way of concrete and stone channels, directing the flow of water to the desired location.
As the population of the Islands grew, so the necessity for more water grew. So the search for more began.
The underwater reservoirs are found by boring deep into the ground, when the water reserve is found the boring stops and horizontal excavations begin to reach the water supply, these excavations are known as galleries.
The water naturally flows to the exterior for domestic and cultivation use, sometimes depending on the location, the water has to be pumped.
Although it would seem that there is an abundant supply of water, great care is and needs to be taken in the amount of water that is used.
The pine forests are essential to the Island and have to be watched constantly to avoid any kind of fire accidental or malicious damage.