Designing Rainwater Harvesting Systems

Book Preface

Rain water harvesting and conservation aims at optimum utilization of the natural
resource that is Rain Water, which is the first form of water that we know in the hydrological cycle and hence is a primary source of water for us. The Rivers, Lakes, and Ground Water are the secondary sources of water. In present times, in absence of Rain Water harvesting and conservation, we depend entirely on such secondary sources of water. In the process it is forgotten that rain is the ultimate source that feeds to these secondary sources. The value of this important primary source of water must not be lost. Rain water harvesting and conservation means to understand the value of rain and to make optimum use of Rain Water at the place where it falls.

Water is the only commodity on Earth for which there is no economic substitute. Seventy-five percent of the Earth’s surface is covered in water, yet only 2.5 percent of it is suitable for human consumption. Of that 2.5 percent, most is locked in polar ice caps or hidden beyond the reach of commercial technologies.2 All life forms on the planet depend on water to survive. Simply stated, water is the basis for all life on Earth. The more technologically advanced humans become, the more water is consumed on a per capita basis. Electricity use within a typical home requires 250 gallons (almost 1,000 L) of water per day per person; the manufacturing processes of computer chips, televisions, and cell phones require water, and the production of a half-gallon (roughly 2L) bottle of soda can take over 1.3 gallons (5 L) of pure water.3
Even the production of food requires tremendous (0.5 kg) of chicken and 1 pound (0.5 kg) of beef requires over 1,600 gallons (6,000 L) of water!4 Historically, an abundance of water, as well as water scarcity, has affected both the growth and decline of every civilization. History teaches that finite water resources need to be managed with the utmost care.