Water Crisis - About 71% of the earth's surface is covered with water, but 97% of this is seawater, 2% is
locked in polar ice caps and glaciers and 1% of water is available as freshwater. We need to conserve every drop of water.
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The Purpose - Rainwater and Groundwater Management
Rainwater harvesting is the accumulation and deposition of rainwater
for reuse before it reaches the aquifer.
Uses include water for garden, livestock and irrigation.
Rainwater harvesting provides an independent water supply during
regional water restrictions. It provides water when there is a drought,
and reduces demand on wells which may enable ground water levels to
In Pune , rainwater harvesting is compulsory for any new society to be
The structures required for harvesting the rainwater are simple,
economical and eco-friendly.
Rainwater Harvesting Systems
Roof-Top RainWater Harvesting System
Rain-Saucer, which looks like an upside
down umbrella, collects rain straight
from the sky.This decreases the
potential for contamination
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• Quality of collected rainwater is better than that of surface water. Contamination is possible by airborne
dust, bird feces, and other debris, so some treatment is necessary, depending on how the water will be
Pre-chlorination - for algae control and arresting any biological growth.
Sedimentation - for solids separation, that is, removal of suspended solids trapped in the water.
Filtration - removing particles from water, Desalination - Process of removing salt from the water.
Disinfection - for killing bacteria.
• Some rain water harvesting agencies in India:
NationalWater Harvesters Network (NWHN).
Centre for Environmental Science, Delhi.
Central GroundWater Authority, Nagpur.
Groundwater Survey & Development Agency,Thane & Pune.
5 Rainwater and Groundwater Management
Groundwater is the water located beneath the earth's surface
in soil pore spaces and in the fractures of rock formations.
Groundwater is naturally replenished by surface water
from precipitation, streams, and rivers when this recharge reaches the
Groundwater is often cheaper, more convenient and less vulnerable to
pollution than surface water.Therefore, it is commonly used for public
water supplies like drinking and cooking.
The study of the distribution and movement of groundwater
is groundwater hydrology.
Rain is the main source of ground water.
Groundwater quality comprises the physical, chemical and biological
qualities of ground water.
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• Recharge area – Rain, Drizzle, Snow
melting, surface water rivers and lakes.
• DischargeAres – Industrial waste and
• The Cycle of GroundWater is often due
to the earth’s gravity.
• Water often finds space from rocks to
travel and accumulate at a specific
location forming aquifer.
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CENTRAL GROUNDWATER AUTHORITY
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In India, Central Ground Water Board (CGWB), a subordinate office of the Ministry of Water Resources, is
the Apex Agency entrusted wIth the responsibilities of providing scientific inputs for management,
exploration, monitoring, assessment, and regulation of ground water resources of the country.
The CGWA is regulating withdrawal of ground water by industries/ projects in 839 Over-exploited and
226 Critical Assessment Units. List of these critical areas has been circulated to the State Pollution
Control Boards and Ministry of Environment & Forests which refer the new industries/ projects to CGWA
for obtaining permission.
Construction of new ground water structures is prohibited in the notified areas. Permission of drilling
tube wells is being granted only to the Govt. agencies responsible for drinking water supply.
Ground water Management – Artificial Recharge
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Artificial recharge is the process by which the ground water is augmented at a rate much higher
than those under natural condition of replenishment.
The basic requirement for recharging
ground water is Source water
Induced Recharge - Rainwater
The rain water in urban area can be
conserved through RoofTop RainWater
HarvestingTechniques for artificial
recharge to ground water.This
technique requires connecting the
outlet/drop pipe from roof of the
building to divert the rainwater to either
Water Saving and Management
Do’s & Don’ts
Use a glass to rinse after brushing of teeth. It needs only half a litre of
water. Keeping the washbasin tap open while brushing teeth wastes at
least four litres of water.
Bathing needs only 20litres of water. Shower bath needs at least
80litres and tub bath 110litres of water.
Washing clothes require 40litres of water; keeping the tap running
during washing consumes 250litres of water.
Water plants with rinse water from the washing machine.
Sprinkling water on the ground needs 10litres of water but hosepipe
watering consumes 50litres of water.
Use a bucket to wash the car, not a hose.
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Therefore, the housing complexes should have proper rain water
harvesting system and draw groundwater for non-drinking
purposes. Even if water from bore-wells is used for toilet flushing
(50lpcd) and cleaning (10lpcd), the load on the piped water
supply will come down to 50%.
This means that the same piped water supply will be sufficient
for double the alarming population growth.
Rainwater and Groundwater
Mahesh M Karane
Bombay Community PublicTrust
Central GroundWater Board
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