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

Double-whammyFlood at the time of droughtRivers will be in spate and then with less water

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

शहरी उत्तर प्रदेश के मल मूत्र प्रबंधन

का मूल्ांकन

शहरी उत्तर प्रदेश का ऐस ऐफ डी

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…..

Catch water where it falls

Trans-Himalayan Region

Zings (Ladakh)

Every region; its own water wisdom

Integrated surface

and groundwater

systems of hill forts

of Jodhpur

Thar Desert

Khadins (Western Rajasthan)

Thar Desert

Indo-Gangetic

Plains

Ahar-Pyne system (Bihar)

Cascade tanks of South India –

engineering marvels

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

Hyderabad:

Built airport on

catchment of Himayat

Sagar

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