Water Supply in Dhaka

Mega City: A Strategic View

Professor M. Habibur Rahman, Ph D

Pro -Vice Chancellor

Bangladesh University of Engineering and Technology (BUET), Dhaka

M. Saiful Islam & Abdullah Al-Muyeed. Ph D

Department of Civil Engineering

Ahsanullah University of Science and Technology

Introduction Dhaka mega city is densely populated with more than

16.4 million in an area about 300 sq. km

The recent water supply requirement of 2100 MLD

The projected demand will be more than 4000 MLD in

the year 2020

The increasing trend of population growth will create

pressure on the existing water distribution system.

The Dhaka Water Supply and Sewerage Authority

(DWASA) cannot provide the recent requirement of

water

A combined water supply system comprising

accounted and unaccounted for water in mega city

Dhaka considering loss diminishing analysis, public

acceptance and awareness and alternate source of

water is the main focus.

The idea is to not only looking for alternative sources

but also to ensure effective and sustainable use of

the current sources that is best suited to meet city

water demand.

DWASA has total 4375348 Water Connection up to

December 2010

System loss in different year of DWASA

01020304050607080

1979 1990-

1991

1991-

1992

1992-

1993

1993-

1994

1995-

1996

2000 2003 2004-

05

2005-

2006

2006-

2007

2007-

2008

2008-

2009

Year

Sy

stem

lo

ss %

• AWWA Standards for Water System Audits

– 1991 “Unaccounted for Water”

– 2000 IWA/AWWA Water Balance • Provides consistent terminology

• Water Use Accounting nothing left “unaccounted for”

• Meaningful Assessment of Revenue and Non-Revenue Water

• System focus

Water Use Accounting

System

Input

Volume

(corrected

for known

errors)

Authorized

Consumption

Billed

Authorized

Consumption

Billed Metered Consumption

(including water exported) Revenue

Water

Billed Unmetered Consumption

Unbilled

Authorized

Consumption

Unbilled Metered Consumption

Non-

Revenue

Water

(NRW)

Unbilled Unmetered Consumption

Water Losses

Apparent

Losses

Unauthorized Consumption

Customer Metering Inaccuracies

Data Handling Errors

Real Losses

Leakage on Transmission and

Distribution Mains

Leakage and Overflows at Utility's

Storage Tanks

Leakage on Service Connections up

to point of Customer metering

AWWA Water Loss Accounting

Water Losses Non Revenue Water

Apparent Losses

• Meter Inaccuracies

• Data Handling Errors

• Unauthorized Consumption

Real Losses

• Leaks in Distribution

• Overflows at Storage Tank

Water

Treatment

Plant

Ground

water

Surface

Water

Authorized

Consumption Billed/Revenue Water

Billed Unmetered

• Estimates

• Flat rates

Billed Metered

• By Sector

• SF Residential

• MF Residential

• Commercial

• Institutional

Water

Treatment

Plant

Ground

water

Surface

Water

Authorized

Consumption Unbilled/Non Revenue Water

Unbilled Metered

• City Parks/Pools

• City Buildings

Unbilled Unmetered

• Fire Fighting

• Street Cleaning

• Line Flushing

Water

Treatment

Plant

Ground

water

Surface

Water

Water Demand Projections 2010 2015 2020 2025

Population in DWASA area 10,290,000 12,320,00

0

14,610,00

0 17,190,000

Served by DWASA (90%) 9,270,000 11,090,00

0

13,150,00

0 15,470,000

Slum population (15%) 1,540,000 1,850,000 2,190,000 2,580,000

Served by DWASA excl slum 7,730,000 9,240,000 10,960,00

0 12,890,000

Water Demand

- Residential l/c/d 140 130 120 110

- Slum l/c/d 35 40 45 50

-

Commercial/i

ndustrial

% 12% 15% 17% 20%

Total Ml/d 1,290 1,480 1,680 1,880

Unaccounted

for water % 35% 25% 25% 25%

Total water

demand Ml/d 1,980 1,970 2,240 2,510

Water Demand Projections (continued)

Water availability

Ground Water Ml/d 1,250 1,175 1,175 1,175

Saidabad SWTP I Ml/d 225 225 225 225 225

Saidabad SWTP II Ml/d 225 225 225 225 225

SWTP III (Khilkhet) Ml/d 500 500 500 500

SWTP IV (Padma) Ml/d 500 500

Total 1,700 2,125 2,125 2,625

Deficit/Surplus (280) 155 (115) 115

Source: Water Supply and Sanitation Sector Programme Support (WSSPS) Phase II funded by

Ministry of Foreign Affairs, Denmark

Analysis/results and implications for

policy and/or research

DWASA need to minimize loss to meet the demand

of water by existing systems

The UFW that is termed as system losses of DWASA

was as high as 75% in 1979.

The system losses were narrowed down to about

41.5% in 2008-2009.

Total UFW of DWASA

Illegal Connection

45%

Physical loss

55%

Key Point-1

Strategic training of DWASA management is

required to minimize UAW, which is in many

developed countries is less than 10%, to mitigate

this issue.

Key Point-2

The alternate future water source is the surface water

But the major source of surface water like rivers and

lakes are in danger because of urbanization of the

huge population.

The possible options are Meghna and Padma rivers,

which are far from the city.

At least 150 MLD of water can be added to water

treatment plant of DWASA

The Government of Bangladesh planned to

implement a surface water treatment plant at Pagla

bringing water from Padma

Key Point-3

DWASA is also working on improving water supply

performance and creating new source through various

projects.

Dhaka Integrated Environment and Water Resources

Management Project,

Dhaka Water Supply and Sanitation Project,

Dhaka water Supply Development Project,

Emergency Water Supply System Expansion and

Rehabilitation Project,

Saidabad Water Treatment Plant (Phase-2) are the

major ones.

Key Point-3(Continued)

These projects are expected to increase water supply

by improving efficiency and creating alternating

sources.

However coordination of all this projects must be

emphasized and ensured.

The average rainfall in Dhaka city is around 2000 mm

per year.

Key Point-4

It is possible to store at least 30 MLD of water

by constructing storage tank on the roofs of the

buildings, which are readily available in Dhaka

city.

The people of the city must be encouraged to

store rainwater and to use this water especially as

a palatable purpose.

Key Point-5

There are also some industries, commercial places

where water is used only for cooling or washing

purposes or may be used in boilers that require

specific treatment for the purpose not all treatment as

performed by DWASA.

So it will be handy to have a secondary supply line in

industrial zones where preliminary treatment of water

will be done and in some cases specific treatment if

necessary.

The cost of this new network can be recovered from

the respected industries.

Key Point-5(Continued)

Using water efficient fixture.

Raising public awareness to minimize per capita water

demand.

Use of recovered water bathroom, wash basin for

flushing purposes, etc.

Considering only 5% recovery the total consumption

of 180 lpcd per person (future Dhaka Population 15

million) and, it is possible to add more than 100 MLD

to the distribution network.