Town/City:

Dhaka

State/Province:

n/a

Country:

Bangladesh

Latitude/Longitude:

23N 90E

Information supplied by

M Kamrul Hasan

ucfbmkh@ucl.ac.uk

Hydrogeology Group
Dept. of Geological Sciences
University of London
Gower St, London WC1E 6BT

0171 388 7614

Dated Mon Jul 29 14:48:15 1996

Information Topics:

City Description:

Dhaka is the capital city of Bangladesh. The area of the city is 250 square km and has a population of 9.0 million. The city has a history of 300 years and over this time the city has expanded from 1.5 sq.km to the present size. The city is located along the north bank of the river Buriganga and present trend of growth is from north to south. Dhaka is situatd on the southern tip of the Madhupur Tract, a Pleistocene terrace. The population density of the city is very high.

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Climate:

Like other parts of the country the climate of the Dhaka city is characterised by tropical monsoon climate. The city experiences three distinct season:the winter (Nov-Feb), dry with temperature 10-20 deg C; the pre monsoon (March- May), few rain with temperature reaching up to 40 deg C and the monsoon (June-Oct), very wet with temp. in the range of 30 deg C. The long term mean annual rainfall for Dhaka is over 2000 mm, about 80-90 % of this falls during monsoon

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Basic Hydrogeology:

The Dupi Tila sands is the main aquifer which comprises of a thin zone of fine sands at the top followed by a thick, relatively uniform medium sand aquifer. The aquifer varies in thickness from 100 to 120 m. The base of this aquifer is a grey clay, at about 120 to 150 m. Madhupur clay overlies the Dupi Tila sands and the thickness of the clay unit is 10 to 20 m. The aquifer was confined to leaky confined at the begining. On continuous dewatering, the piezometric level has fallen for about 30 m and the aquifer has become unconfined. The quality of the water in the northern part of the city is very good. There is some pollution in the industrial area and also to recharge by polluted river water. The actual salinity is well within the range of Bangladesh standard. Natural recharge- mainly from two different sources; direct infiltration and deep percolation of rainwater. Leakage from water mains in the range of 25-35% comes as a urban recharge. Abstraction by water wells is the main discharge. There is also base flow to rivers.

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Water Use:

The municipal water supply is mainly derived from groundwater storage(90%). The surface water contribution is only 10%. Dhaka Water and Sewarge Authority (WASA) abstracted 160 million cubic meter for domestic water supply and private wells (114200 m3/d) for domestic and industrial uses. Irrigation use is very small.

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Groundwater Issues:

Due to over expoitation the water level is declining at the rate of 0.75 m per year. The cost of tubewell sinking is increasing gradually. There is a possibility of induced recharge from the surrounding rivers which are polluted by industrial effluent. The water quality is deteriorating gradually. There is also a possibility of subsidence. Mining fear!

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Groundwater Problems:

The present supply of water is meeting only 50 % demand. There are a number of pollution problems from industrial effluent, landfill, intrusion of river water etc. The abandonment of wells are common occurrence due to water level decline at a higher rate. The hydrologic cycle particularly the flow pattern has already been reversed.

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Solutions:

Dhaka WASA tries to overcome the water shortage problem by installing more and more wells. Declining water level problem is overcome by resinking water wells. Present management is very poor and WASA is running without Hydrogeologist. There is no proper monitoring programmme- only water level is recording from time to time. No quality monitoring at all. WASA has undertaken a programme for surface water treatment few years ago, but yet to be implemented.

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References and Other Author(s):

Dr.W G Burgess, Dept. of Geological Sciences, Univesity College London,  
Gower Street, London WC1E 6BT 

Dr. K M Ahmed, Dept. of Geology, University of Dhaka, Dhaka-1000, Bangladesh. 


Mr. Peter Ravenscroft, Mott MacDonal Ltd. 122 Gulshan Avenue, Dhaka-1212,  
Bangladesh.
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Contacts:

M Kamrul Hasan
Hydrogeology Group
Dept. of Geological Sciences
University College London
Gower Street
London WC1E 6BT

Phone: +44 171 387 7050 (ext.2828)
Fax Number: +44 171 388 7614
Email Address: ucfbmkh@ucl.ac.uk Back to Topics

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