Benefits of Rainwater Harvesting for society and the environment
Rainwater harvesting is a versatile and effective strategy that offers a wide range of benefits for individuals, communities, industries, and the environment. It plays a crucial role in sustainable water management and resilience building..
⦁ Rainwater is a relatively clean and free source of water, at the point
where it is needed
⦁ It promotes self-sufficiency and conserves water
⦁ It uses a simple technology which makes it easy to maintain
⦁ Provides safe water for human consumption after proper treatment
with low running costs
⦁ Can supplement other sources of water supply
⦁ Reduces flood flows & dependency on groundwater
⦁ Improves the quality of groundwater through dilution when recharged
⦁ Reduces soil erosion as the surface runoff is reduced
⦁ The structures required for RWH are simple, economical and
eco-friendly.
⦁ RWH system can also be set up with the already existing infrastructure
⦁ Yields high-quality water - pure, soft, with low minerals, free of organic
matter & Chemicals
⦁ In coastal areas, where the water is saline, RWH is the panacea
⦁ Saving energy to lift groundwater (One-meter rise in water level
saves 0.40-kilowatt hour of electricity)
“"Rain to the Rescue: Harvest, Reuse, Renew."”
raise awareness about the importance of rainwater harvesting and encourage people to take action to conserve this precious resource.
Rain Water Harvesting is Most Suitable When
⦁ Groundwater is scarce
⦁ Groundwater is contaminated
⦁ The terrain is rugged or mountainous,
⦁ Seismic & flooding events are common,
⦁ The aquifer is at risk of saltwater intrusion,
⦁ Electricity & water prices are rising
⦁ Water is too hard or mineral-laden
Rain Water Harvesting Filtration Process
Filters are made of sponge and a mixture of sand, gravel, and charcoal. After
first flushing and filtration water is led into underground sumps (which are
very common in Bangalore) or to a new storage tank. The overflow from this
tank is taken to an open well to recharge the aquifer. The geological formations
are predominantly granite and granitic gneiss, with joints and fractures in
abundance due to the intense chemical weathering of rocks. The depth of weathering
varies from 0.2 m to 20 m. This geological set-up offers an immense scope for
the recharging of ground aquifers. The undulating terrain with gentle slopes draining
into lakes offers an ideal situation for water harvesting. In the urban area of
Bangalore, water bodies cover about 5 percent of land.
The potential of RWH water availability through Rooftop
Parameter Measure
Total Annual average rainfall 970mm
Total no of rainy days 60 Rainy days
Peak hour intensity of rain in Bangalore 60mm/hr