07-09-2016, 03:13 PM
1453610527-rainwaterharvesting.pptx (Size: 2.61 MB / Downloads: 7)
What is Rainwater Harvesting?
Rainwater harvesting is a technology used to collect, convey and store rain water for later use from relatively clean surfaces such as a roof, land surface or rock catchment.
Why Rain Water Harvesting ?
To get clean drinking water
Free source
Saves high quality drinking water sources
Reduces the potable water consumption
Where Rainwater Harvesting is to be used?
In dry zone areas
Coastal belt where ground water is saline, ( tsunami effected areas)
Hilly areas where ground water table is low
Where it is not possible to extract ground water or have no other water sources
Criteria for Selection of Water Harvesting Technologies
Type and size of catchment area
Local rainfall data and weather patterns
Length of the drought period
Alternative water sources
cost of the rainwater harvesting system.
Various ways of harvesting water
Capturing run-off from rooftops
Capturing run-off from local catchments
Capturing seasonal flood water from local streams
Conserving water through watershed management
Roof top harvesting systems
Although rainwater can be harvested from many surfaces, rooftop harvesting systems are most commonly used as the quality of harvested rainwater is usually clean following proper installation and maintenance. The effective roof area and the material used in constructing the roof largely influence the efficiency of collection and the water quality.
. Collection or Catchment Area
A collection or catchment system is generally a simple structure such as roofs and/or gutters that direct rainwater into the storage facility
Roofs are ideal as catchment areas as they easily collect large volumes of rainwater.
The amount and quality of rainwater collected from a catchment area depends upon the rain intensity, roof surface area, type of roofing material and the surrounding environment
Roofing materials that are well suited include slates, clay tiles and concrete tiles.
Roofs should be constructed of chemically inert materials such as wood, plastic, aluminium, or fiberglass.