The source of the island’s water actually lies far below the surface in a series of vast natural water reservoirs. It might not rain often on Tenerife but, when it does, it tends to rain heavily and this water drains through the porous rock collecting in large underground pools.
The island’s numerous pine forests play an essential role in water production on the island collecting dew by night and water from the clouds that frequently envelope the mountains – plus snow-melt from Teide in the winter months. This water runs through the roots of the pine trees, collecting far underground.
The Arabs first introduced irrigation to Spain. They were experts in transforming dry land into arable farmland. When the Spanish conquistadors came to the Canaries, they passed on this valuable knowledge and villages began to grow around the natural springs. However, as the population increased, so did the need for water over larger areas for domestic and agricultural use. Consequently, a series of concrete and stone channels were built to transport water further afield.
As demand began to exceed supply, locals were forced to search for more abundant supplies. By boring into the ground, they discovered vast reservoirs, hidden below the surface. Once a site was discovered, they would dig horizontally to the source to release the water. These horizontal tunnels are called Galleries and provide most of the water requirements on Tenerife. In most cases, the water runs freely however sometimes it needs to be pumped.
Island authorities constantly monitor the water supplies on Tenerife and great care is taken to maintain the sources – including, in particular, the pine forests.
If you look closely – particularly in mountainous areas – you will see the network of pipes which run around the island. For example, a pipeline runs round Los Gigantes from Masca, feeding Los Gigantes town with its supply. A similar pipeline runs above Costa Adeje, clearly visible on the hillside.