1. Workshop on
ACTION RESEARCH ON GROUNDWATER BUFFERING IN BANGLADESH
24 February, 2011
Prospects of Artificial Recharge for Augmentation of the Upper Dupi Tila Aquifer in Dhaka City, Bangladesh
Sarmin Sultana
Department of Geology, University of Dhaka

2. Presentation Outline What is AR & what are the techniques
Why AR in Dhaka city
What is the source of water for AR
Objectives of this study
Results and discussion
Conclusions
On going research

3. The Megacity Dhaka Needs no introduction
Water Demand and Supply

4. Uniqueness of Dhaka in terms of GW problem
Why AR in Dhaka city
Uniqueness of Dhaka in terms of GW problem
GW Dependant City
No imported water
Big Gap between supply and Demand
Heavy GW abstraction and well deepening
Rate of water table decline 3.5 m/y
Aquifer dewatering
No GW management !

5. Water Table Elevation Contour
Cone of depression
1970
1980
1995
2007
GW hydrograph of Upper Dupi Tila
demonstrates a steady down ward slope.
Water Table Elevation Contour
for dry season as on 2008

6. Is going Deep a sustainable Solution?

7. Rainfall in Dhaka GW hydrographs and
Mirpur (GT )
Dhaka station (R009}
GW hydrographs and
corresponding 7-day rainfall are plotted for 1977 and 1993.

8. Objectives
To estimate the current open space available for natural recharge to take place;
To delineate potential zones for implementing site-specific artificial-recharge techniques using GIS analysis; and
To assess suitability and applicability of Artificial Recharge in Dhaka.

9. Natural Recharge Area Map
Bar Diagram of Recharge Area Classes
Area in %

10. Infiltration Test at the pond of Institute of Fine Arts
Status of the pond immediate after rain
Status of the pond after 3 days
from raining

11. Rules for selecting prospective zones of artificial recharge
Potential Zones
Rules for selecting prospective
zones of artificial recharge

12. Volume of Rainwater Available in Dhaka city (Sources: BBS)
City area
(sq. km)
Avg. annual
rainfall
(m)
Total volume
(M L)
No of total concrete
house available for
rain water collection
Each roof
area (sq, m)
Total roof
area (sq.
km)
Yearly total
volume of
rainwater
(ML)
Daily Total Volume
Of Rainwater (MLD)
370 2
740,000
6,78,000*
110
74.58
149160
408.65
If 30 % of this water can be collected, then more than 100 MLD water will be available to recharge the aquifer artificially.
Number of abandoned wells of DWASA.
R 1
R 2
R 3 R4 R5
Total
175 47 21 15 6
264
Production well
Production well
Other Options
Dredging and re-excavation of khals
Avoid construction along faults
River dredging and Bank filtration
Systematic Clay Mining
Abandoned well

13. Site Specific Artificial Recharge Technique Map
Rules for selecting sites of
definite artificial recharge methods
No of
Locations
Clay
thickness
(m)
Method 6
10 – 15
Trench pit
40 – 50
Injection well 2
3 – 7
Dug well 3
5 – 15
Lateral trench with vertical shaft 1
0 – 10
Spreading Technique
20 – 25
Retention pond with well
25 – 35
En-echelon Dam
15 -30
Check dam
Dhaka has high potential for Artificial Recharge

14. ACTION RESEARCH ON GROUNDWATER BUFFERING IN BANGLADESH
Workshop on
ACTION RESEARCH ON GROUNDWATER BUFFERING IN BANGLADESH
24 February, 2011
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