AtacamaWhere rain never falls, and water comes from the sky

by Fred Foster

http://ngm.nationalgeographic.com/ngm/0308/feature3/map.html

The Atacama Desert is the driest area on Earth.

Located in northern Chile, some areas have not had rain in 400 years.

Photo: NASA World Wind

The anticyclone of the Pacific brings cold, dry air north from Antarctica...

Which makes for a

very dry, very cold

desert.

Public domain

The Rain Shadow Effect

Trade winds from the south Atlantic gather against the Andes mountains, and deposit precipitation in the Amazon rain forests.

www.extremescience.com

Rain Shadow

http://eco-antropologia.blogspot.com/2009/12/omo-se-cazaba-el-guanaco-en-tiempos.html

Chilean Costal Range

http://www.kalipedia.com/kalipediamedia/geografia/media/200806/05/geochile/20080605klpgeogch_27_Ies_SCO.jpg

Fog clouds

A dense, drizzling fog on the Pacific coast of South America, in Ecuador, Peru, and Chile. The garúa may last a long time during the six winter months. It is associated with the cooling of ocean air over the cold waters of the Peru Current. The term “garúa climate” is used to designate the climate of deserts located on the coasts of continents that are washed by cold ocean currents.

http://encyclopedia2.thefreedictionary.com/garúa

Camanchaca / Garúa

http://www.ciencia.cl/CienciaAlDia/volumen2/numero2/articulos/rroman/caman.jpg

Marine fog, camanchaca, forms against the coast range

http://www.tenorural.com/wp-content/uploads/2009/05/captanieblas.jpg Ilustración: Álvaro Valiño

http://www.paxgaia.ca/pictures/spider_web_with_dew_drops03.jpg

The principle of fog harvesting

http://www.tenorural.com/wp-content/uploads/2009/05/captanieblas.jpg Ilustración: Álvaro Valiño

http://tectonicablog.com/wp-content/uploads/2009/11/090422123615_sp_atrapanieblas_gal1_526x3-455x341.jpg

In 1992, a fog harvesting project onEl Tofo mountain produced 15,000 liters (~4000 gallons) of potable water per day for the village of Chungungo.

http://tectonicablog.com/wp-content/uploads/2009/11/por-cruz_fr-4-cc-440x330.jpg

Detail of the collection trough

Originally the fog harvesters were to provide water for a reforestation project.

This expanded to become the municipal water supply for Chungungo. An unintended consequence was the population of the village swelled from 300 to 900 (200%) and the collectors could not maintain a reliable supply of water.

Eventually a pipeline was installed to bring water from theLos Choros river, 20 km away, at a cost of US$1 Million.

Too much of a good thing?

http://www.idrc.ca/en/ev-30617-201-1-DO_TOPIC.html

Slide 2: Photo: NASA World Wind

Slide 3: http://ngm.nationalgeographic.com/ngm/0308/feature3/map.html

Slide 4: US Army Cartography Service (public domain)

Slide 5: www.extremescience.com

Slide 6: Ahrens, C. Donald. Meteorology Today. Belmont, CA: Brooks/Cole, 2009

Slide 7: http://eco-antropologia.blogspot.com/2009/12/omo-se-cazaba-el-guanaco-en-tiempos.html

Slide 8: http://encyclopedia2.thefreedictionary.com/garúa

Slide 9: http://www.ciencia.cl/CienciaAlDia/volumen2/numero2/articulos/rroman/caman.jpg

Slide 10: http://www.tenorural.com/wp-content/uploads/2009/05/captanieblas.jpg

Slide 11: http://www.kalipedia.com/kalipediamedia/geografia/media/200806/05/geochile/20080605klpgeogch_27_Ies_SCO.jpg

Slide 12: http://www.paxgaia.ca/pictures/spider_web_with_dew_drops03.jpg

Slide 13: http://www.tenorural.com/wp-content/uploads/2009/05/captanieblas.jpg

Slide 14: http://tectonicablog.com/wp-content/uploads/2009/11/090422123615_sp_atrapanieblas_gal1_526x3-455x341.jpg

Slide 15: http://tectonicablog.com/wp-content/uploads/2009/11/por-cruz_fr-4-cc-440x330.jpg

Slide 16: http://www.idrc.ca/en/ev-30617-201-1-DO_TOPIC.html

Works cited and sources