There is no shortage of water on earth. But very little of it is actually usable. More than 97 percent of the earth’s water is seawater, two percent is locked in icecaps and glaciers, and a large proportion of the remaining one percent lies too far underground to be exploited.
The proportion of usable water to the earth’s entire supply is equivalent to half a teaspoon out of 100 litres.
Agriculture consumes the largest share of all the water taken from rivers, lakes and aquifers, estimated 65 percent of the global water use.
Industries take the second biggest consumer of global water bodies.
Households, schools, businesses and other municipal activities account for less than a tenth of the earth’s water consumption.
According to the United Nations World Water Development Report (WWDR4), released on March 2012 at the 6th World Water Forum in Marseille, Asia and Pacific region is experiencing intensive use of water resources and affecting the region’s capacity to meet its water needs due to rapid urbanization, economic growth, industrialization and extensive agricultural development.
Even relatively water-rich countries of the region, such as Malaysia, Indonesia, Bhutan and Papua New Guinea, now face water supply and quality constraints in their major cities as a result of population growth, growing water consumption, environmental deprivation, damaging agricultural activities, poor management of water catchment areas, industrialization, and groundwater overuse.
Extreme weather conditions also endanger the access to water and sanitation.
Droughts are unavoidable, provoke natural disasters, reduce yields of agricultural crops, and affect human cultural patterns.
Droughts reduce drinking water availability and floods and storms can damage basic water infrastructure and spread disease.
Recently many regions around Malaysia experienced the adverse effects of a long, hot weather and because of the drought some local authorities imposed stringent water restrictions and encouraged householders to implement water conservation measures to lower the demand for reticulated water.
A new development in rainwater harvesting is very important to make sure that there is no water shortage in the future.
Rainwater harvesting system has been implemented in many countries such as USA, Japan, China, India, Germany and Australia to support the increasing water demand.
The integration between rainwater harvesting system and existing conventional water supply systems will help to meet the demand and contribute in the sustainability of the water supply.
Some Advantages of Rainwater Harvesting Include:
1. Rainwater harvesting can co-exist with and provide a good supplement to other water sources and utility systems
2. Rainwater harvesting provides a water supply buffer for use in times of emergency or breakdown of the public water supply systems
3. Rainwater harvesting can reduce storm drainage load and flooding in city streets
4. Rainwater harvesting technologies are flexible and can be built to meet almost any requirements