Catchwater

A catchwater device is a large-scale man-made device for catching surface runoff from hills and the sky from precipitation by channeling it to reservoirs for commercial and domestic use later. Freshwater is a scarce natural resource due to pollution, droughts, and overpopulation. Catchwater is a sustainable mechanism to increase freshwater in areas facing droughts or polluted waterways.

Catchwater drains may take the form of concrete canals, such as in Hong Kong, where there are many. Alternatively, they may take the form of a large concrete sheet, smothering a hill, and preventing rainfall from entering the rock strata, with a smaller channeling system for transport of the water to the storage tank - this latter system is in operation in Gibraltar. In Hong Kong there is approximately 120 km of concrete channels, used as gutters built along hillsides in order to direct freshwater runoff into reservoirs for local water consumption. These catchwaters can overflow and cause dangerous hazards erosive streams and blockages if they are overflowed.

An earthship drain is water that is collected from impervious surfaces that are channeled into cisterns. A cistern is a well located underground. The water within these underground wells is heated by the sun. The water that is stored is used in domestic ways for washing dishes and bathing. Once water is used it is cycled and filtered in a module to be reused again

Rainwater tanks, also known as rain barrels in North America, are used to collect runoff coming from precipitation to prevent contamination from entering waterways. The only use of water from rain barrels is used for commercial use such as gardening and agriculture. Rain barrels are large containers that are connected to buildings through a gutter system which catches runoff from roofs. Many households use rain barrels as a substitute for a to reduce the amount of water they waste for recreational activities.

A Rain garden is a depression in the ground covered by vegetation that helps filter and restore freshwater back into the water cycle. Rain gardens are used to decrease the speed of water by capturing the water, so it does not become surface runoff through infiltrating the soil.

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