Making Ganga basin cities
water sensitive: imperative
and opportunity in our climate
risked world
Sunita Narain
CSE
Rivers and hydrological challenges
Today it does not rain; it pours
Cities drown; flooding common
We know that extreme rain events are
linked to climate change
We will get more in fewer number of rainy
days
Add to hydrological challenges – will
mean less water in longer lean water
season
20201000 extreme rain events in first 12 days of August
2021July has already seen floods; extreme rain –600-800% more than average; all the year’s rain in matter of hours and days
Rising heat will add to Ganga’s water stress
Rising heat means
Dry moisture in soils – increase the need for irrigation;
add to land degradation and dust formation
Increased evaporation rate – water will depleted faster
that is stored in surface water structures
Drive up the use of water – from drinking to irrigation to
fighting fires in forests and building
Water management will be crucially important in the
age of climate change
Ganga hydrological challenge
Cities take water and return sewage
This adds to water pollution; but also
degrades the water that is available
Water stress on rivers increases
Now with climate change; extreme rain
and heat; the hydrological stress on
rivers will increase
India will not follow transition of rich world –
people move to cities; economies move to service-
industry; water moves with it
Agenda for Ganga cities
Use flood/rain water as sponges in the city;
recharge groundwater
Multiple benefits
A. Mitigate flooding and damage to properties;
health risks
B. Improve local water availability for use –
reduce demand on surface/river water
C. Use lakes/ponds for tertiary water treatment –
discharge treated effluents for recharge and
reuse
Learn from traditions…
In 1997 we published Dying
Wisdom:
Rich learning of our
traditions.
Enormous diversity,
technological sophistication.
Each region had its own
system to hold, capture
rain. Zings, ahars, johads,
tankas, phad…..
Agenda: land for water security
Hold rain where it falls
Value land for water
Provide legal protection for city lakes,
catchment and drainage systems
Rejuvenate sponges of cities for water
security and for Ganga to flow
Losing lakes
Ahmedabad:
built over its water
Case in high court to protect
lakes
Fought by builders
Do not want catchment
protected
Do not want area around
lake demarcated
1925 1994
Wet land Built up
Green cover
Mumbai > flood cushions built up; Entire city went
under water
Groundwater: critical for city’s water security
Water supply does not reach all, only few.
No alternative but to move to groundwater
Millions depend on private wells, tanker mafia, bottled water
Water supply shortfalls show up in the groundwater table of the city
We must plan for local water supply; mitigate floods; cut costs of supply; reduce water stress in rivers
Where
pipeline does
not reach
People
depend on
groundwater
Falling
groundwater
levels tell us
about
inequity
Improving local water
security will also control
pollution
Sewage management in
city needs funds
But cost of energy high;
water losses high in
bringing water long
distances
Local water can improve
accounts of water
utilities
Allow for more
investment in sewage
management
Traditional knowledge for Ganga’s future
• Plan and build distributed sources of water; cut length of pipeline for water supply
• Plan and build distributed sewage treatment; cut length of pipeline for wastewater treatment
• Harvest the raindrop
• Reuse the treated wastewater: waste to water
Partnership/collaboration for change
We will work with Namani Gange to take
forward this agenda
Learn, share and build practice on:
How to harvest the raindrop; at homes; in
parks; in city lakes and ponds
How to improve lake protection; rejuvenate
and treat wastewater and do groundwater
accounting
How to build local sewage treatment for reuse
Our common objective: Water sensitive and
waste wise cities for Ganga
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