Water

Abstract

Water scarcity is without a doubt on of the greatest threats to the human species and has all the potential to destabilise world peace. Falling water tables are a new phenomenon. Up until the development of steam and electric motors, deep groudwater could not be exploited. Now, hoever, deep drilling and powerul pumps are able to probe many kilometres down into the earth for aquifers. Unfortunately, once dry, they remain dry, as seasonal rain does not penetrate deeply egough to replenish them. Water tables have been falling in many countries, most nobaly in China, India and the USA, which together produce nearly half the world's grain. Already many countries have pumped much of their underground aquifers dry. Clean water is becoming increasingly scarce: green buildings aim therefore to develop systems that minimise consumption and pollution of this resource. Careful design is used to develop rainwater harvesting, plumbing and ecological sanitation systems that enable buildings to be self reliant for their water needs and avoid polluting water. This reduces the requirements for large-scale water and sanitation infrastructure that consumes energy and can be highly wasteful.