Water Woes of Mumbai

P.K. Charankar

Consulting EngineerRetired Deputy Municipal Commissioner

(Special Engineering)

Municipal Corporation of Greater Mumbai

2

Existing Water Supply Sources

Sr. No.

Name of the Source Year of Completion

Qty of Water Supply (MLD)

Total Qty of Water Supply

(MLD)(Cumulative)

1 Vihar Lake 1860 110 110

2 Tulsi Lake 1879 18 128

3 Tansa Lake 1892 to 1925 485 613

4 Modak sagar & Upper

Vaitarna

1957 1142 1755

6 Bhatsa (3 SCHEMES

TOGETHER)

1974 to 2007 1700 3455

Middle Vaitrna 2014 455 3910

Inclusive of 120MLD En-Route Supply

3

Water Supply: 3900 Mld

Major Water Treatment Plants:

Bhandup: Rated capacity 1910 Mld, working at 2100 Mld + 990 Newly added in 2014

Panjarapur: Rated capacity 1365 Mld, working at 1365 Mld

Vehar + Tulsi : Rated capacity 90 Mld

Master Balancing Reservoirs : 2 (Yewai & Bhandup)

Service Reservoirs : 26

Length of water mains : 4000 Kms

No. of Distribution Zones : 109

No. of Leak-detection Zones : 615

No. of daily operated valves : 800

Mumbai Water Supply Scenario

4

Sources of Water Supply For Mumbai

MIDDLE

VAITARNA

GARGAI

UPPER

VAITARNA

LOWER

VAITARNA

PINJAL

BHATSATANSA

Bhatsa release

Pise Pumping

1315 Mld to City

2435 Mld to City

670 Mld

2315 Mld

430 Mld

1765 Mld

VaiternaTansa

2020 Mld

Overview of Water Supply to

Mumbai

En route

120 Mld

Other sources

120 Mld

Raw water

Treated water

Net Flow to City: 3750 Mld

6

Length of water mains : 4000 KmsNo. of Distribution Zones : 109No. of Leak-detection Zones : 615No. of daily operated valves : 800Population : 13.3 millions

Mumbai Water Supply Scenario

Reservoirs

Distribution Mains

Service Mains

Consumer Connections

Source

Demand Supply Scenario

2001 2011 2021

12.2 m

14.4m16.7m

Source: Dr. Chitale Committee Report

2902

3033

4392

3798

38134243

Demand in Mld

Supply in Mld

Present Supply 3900 Mld

Simple Arithmetic

Total Supply = 3900 Mld

Estimated UFW = 30%

Net Available = 2730 Mld

Estimated Population = 20 Millions

Net availability/person = 136 litres/head/day

It is less than international standards but

Mumbai is not a water stressed area

Broad Conclusion

Sufficient Water but

unequal distribution

leads to water

scarcity in this City

10

Challenges of Mumbai’s Water Supply

Issues pertaining to Quantity of Water• Growing demand and problem of inequitable distribution owing to sub-

optimal pressure regulation.

Issues pertaining to Quality of Water• Contamination due to aging network and intermittent supply, peaking

during monsoon

Issues pertaining to hours of supply• Intermittent supply. Average duration of supply: 2-4 hrs.

Issues pertaining to “unaccounted for water”• Physical as well as revenue losses amounting to 20-25%

Issues pertaining to Cost of Operations and tariff

structure• Need to cover growing operational costs and generate surplus for

investments in water supply infrastructure through efficiency

enhancement measures and timely and periodic revision of user

charges

11

Action Plan For Improvement in

Water Sector

Source Augmentation

Better Supply-side

Management

Better Demand-side

Management

12

Action Plan For Water Sector

Source Augmentation

13

Long Term Plan For Source Augmentation

In the year 1993, the Govt. of Maharashtra appointed an expert committee under the

chairmanship of Dr M A Chitale (Ex-Secretary, Irrigation Dept) for advice on the long term

planning for augmentation of water supply to Mumbai. The committee recommended

development of following sources in phases

The GoM has accepted the Dr. Chitale Committee recommendations and has

approved allotment of these sources. The MCGM has therefore taken up the Middle

Vaitarna Project as an immediate additional source of water supply. The same was

completed in 2012. It is expected that the supply will be available from October

2014.

Simultaneously feasibility of Gargai and Pinjal Projects is currently being studied

Sr. Source Basin Yield

No. [MLD]

1 Middle Vaitarna Vaitarna 455

2 Gargai Vaitarna 455

3 Pinjal Vaitarna 865

4 Kalu Ulhas 590

IV MUMBAI (MIDDLE VAITERNA) WATER

SUPPLY PROJECT

Completed in 2012

Tunnel for Conveyance completed in 2014

Water Availability 455 Mld

Challenges in Source Augmentation

All new sources are situated in

Environmentally sensitive areas. For

Example: Gargai is located in Wildlife

Sanctuary

Forest land will have to deforested.

Land acquisition of revenue land is costly.

Rehabilitation of Project Affected People is a

great challenge for executing agency

Towards Better Supply-side

Management

Challenges on Supply Side

Management

Leakages in transmission and distribution

network

Contamination

Unequitable distribution

Reduction in NRW -Physical leakage

-Thefts

- Incorrect metering

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Supply Side initiatives: Distribution

NetworkComprehensive Water Supply Distribution Improvement Programme

1. Division of the entire city into various District Metering Areas (DMAs)

2. Hydraulic study of DMAs, each comprising about 1000 connections.

3.100% Consumer metering, Bulk metering and District Metering set-up.

4. Water balance and estimation of NRW/UFW in each DMA

• Leakage detection, Repairs / Rehabilitation / Replacement plan

• Water balance of each DMA

• Install pressure regulating devices for equitable distribution

• Digital mapping of the utility on GIS compatible base maps.

• Hydraulic modeling of the entire network.

• Introduce / upgrade ‘SCADA’, the distribution management tool.

Approach

Universal Metering Policy Matter. It has been

accepted in principle and is

being implemented

Telescopic Tariff Structure

for Water Consumption

Policy Matter. It has been

implemented for certain

categories

Water Distribution Network

Up gradation

Hiring Consultancy Services and

Implementation of

Suggestions under their

supervision:

A Result Oriented Consultancy

Agreement

Reduction in UFW/NRW

& 24 X 7 Water Supply

Updating of water network maps with

universal reference points.

Present Status: Some part of the network has

been digitalized. Newly laid pipelines have

not been integrated in the digitalised version.

OBJECTIVE 1

OBJECTIVE 2

Estimation and Reduction of UFW for the entire city network.

I-Phase –

a) Providing Bulk Measuring Meters on various zones.

b) Estimation of UFW under intermittent water supply conditions by actual measurement of flows .

c) Reduction in UFW upto target level of 10% under existing conditions of intermittent water supply by implementing the suggestions

II-Phase –

Reduction in UFW up to target level as per minimum night flow on 24 hour basis.

Zone-wise hydraulic analysis of primary,

secondary and tertiary water supply

network.

Water balance in each zone

OBJECTIVE 3

24 x 7 Water Supply for entire city

(with available water supply which could be of

the order of 3500 Mld for a population of about

15 millions and NRW limited to 15-18%, it is

expected that the situation is conducive for 24

X 7 water supply.

The terrain, variation in population density are

the challenges in supplying water on 24 X 7)

OBJECTIVE 4

Replacement of Old Water Mains by

Underground Tunnels

Towards Better Supply-side

Management

Condition of Some of the Old

Pipelines

PRESENT STATUS

There are 11 outlets of Malbar Hill Reservoir varying in diameter from 450 mm to 1200 mm, passing through Chaupati Beach & further along the Netaji Subhashchandra Bose Road. Most of these mains are nearly 50 years old.

The rehabilitation of these outlets lines is very difficult because of social and physical cost impacts. Therefore, 8 out of 11 outlets are replaced by tunnel

TUNNEL FROM MAROSHI TO

RUPAREL COLLEGE

TBM CUTTER HEAD-FRONT VIEW

RCC LINED TUNNEL

Towards Better Demand-side

New housing projects with 135 lpcd

Recycling of Grey water

Telescopic water tariff to encourage the people to conserve water

Equitable Water Distribution

Technological Challenges

Replacement & rehabilitation of old water mains in confined space

Reliable and robust water leak detection equipments/systems

Reliable and robust water meters

Management consultancy in reduction in NRW in such a complex situation

Utility mapping for old pipelines

Quality Aspects

1. Protection of Water Sources

2. Treatment Facilities and adequacy

3. Possibility of Contamination of water

supply through water distribution

network.

General Characteristics of Raw Water

Turbidity: From lake sources-Max 20 NTU

From river source- Max. 50 NTU

pH 6.8 to 7.5

SS Max. 20 mg/lit

TDS Max 75 mg/lit

No hardness

No presence of any toxic material

Protection of Water Sources: Modak

Sagar

Bhatsa Abstraction

River Abstraction at Pise

Quality Assurance at Treatment

Plants

1. The entire water supply is treated at two major water

treatment plants: Bhandup and Panjarapur

2. The treatment consists of conventional treatment

units such as pre chlorination, Settling, filtration, post

chlorination. This treatment is adequate as all the

sources are away from inhabitation and well

protected.

3. There are full scale laboratories with trained staff and

state of art laboratory equipment

4. for quality control of water

5. The quality is fully ensured (as per IS as well as WHO

Standards) while the water leaves treatment plants.

Challenges in Protection of Water

mains in some parts of City

Protection of Distribution System

Water Woes Summary

Intermittent Water Supply: Leading to ingress of water from

outside into water mains during non supply hours.

Sufficient water but unequal distribution leading to wrong

impression about availability.

Complicated procedure for new water connections

Low pressures in distribution system

Old pipelines which are heavily corroded

Hidden population: Census 2011 data shows declining

population of Mumbai- Creating problems for planning.

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